Work vehicle

Abstract

This work vehicle includes: a plurality of work devices; a first storage part 11 capable of storing hydraulic oil; a second storage part 12 capable of storing hydraulic oil; and a hydraulic pump for supplying hydraulic oil to the work devices. The second storage part 12 is provided at a position higher than the upper end part of the first storage part 11. A connection oil passage 16 connected across the first storage part 11 and the second storage part 12 and capable of passing hydraulic oil is provided.

Description

Work vehicle

[0001] The present invention relates to a configuration for supplying hydraulic oil to a work device installed in a work vehicle.

[0002] For example, Japanese Patent Application Laid-Open Publication No. 2022-101186 discloses a sugarcane harvester, which is an example of a work vehicle. In this publication, the vehicle is equipped with multiple work devices such as a reaping unit and a transport device, and is configured so that hydraulic oil in a reservoir is drawn into a hydraulic pump and supplied from the hydraulic pump to the work devices, thereby operating the work devices.

[0003] Japanese Patent Application Publication No. 2022-101186

[0004] In a configuration in which hydraulic oil from a reservoir is drawn into a hydraulic pump and supplied from the hydraulic pump to a working device, the occurrence of cavitation is a concern. When the hydraulic pump draws hydraulic oil from the reservoir, the pressure of the hydraulic oil temporarily drops. It is thought that this causes air bubbles to form in the hydraulic oil, and cavitation occurs when the air bubbles burst as the hydraulic pump increases the pressure of the hydraulic oil. The present invention aims to suppress the occurrence of cavitation in a work vehicle in which hydraulic oil from a reservoir is drawn into a hydraulic pump and supplied from the hydraulic pump to a working device.

[0005] The work vehicle of the present invention is provided with a plurality of working devices, a first reservoir capable of storing hydraulic oil, a second reservoir capable of storing hydraulic oil, and a hydraulic pump that supplies hydraulic oil to the working devices, and the second reservoir is provided at a position higher than the upper end of the first reservoir, and is provided with a connecting oil passage that connects the first reservoir and the second reservoir and allows hydraulic oil to communicate.

[0006] According to the present invention, a first reservoir and a second reservoir are provided, the second reservoir being located higher than the first reservoir, and a connecting oil passage connecting the first reservoir and the second reservoir. The second reservoir is located higher than the first reservoir. Therefore, when hydraulic oil is filled into the first reservoir and the second reservoir until the hydraulic oil level is located in the second reservoir, the pressure of the hydraulic oil in the first reservoir increases. In this state, when the hydraulic oil in the first reservoir is drawn into the hydraulic pump, the pressure of the hydraulic oil in the first reservoir is already increased. Therefore, even if the pressure of the hydraulic oil temporarily decreases due to suction by the hydraulic pump, the pressure of the hydraulic oil is unlikely to decrease to a pressure at which bubbles are generated. Since the pressure of the hydraulic oil is unlikely to decrease to a pressure at which bubbles are generated, the generation of bubbles is suppressed, and the occurrence of cavitation is suppressed. This improves the durability of the hydraulic pump that draws hydraulic oil from the first reservoir.

[0007] In the present invention, it is preferable that the connecting oil passage connects an upper portion of the first reservoir portion to a lower portion of the second reservoir portion.

[0008] According to the present invention, the connecting oil passage connects the upper part of the first storage portion and the lower part of the second storage portion. This prevents the connecting oil passage from being longer than necessary, thereby simplifying the structure. By connecting the connecting oil passage to the lower part of the second storage portion, hydraulic oil from the second storage portion can easily enter the connecting oil passage, thereby reducing hydraulic oil remaining in the second storage portion. This reduces contaminants remaining in the second storage portion. As a result, when hydraulic oil from the second storage portion is sucked into the hydraulic pump, less contaminants flow into the hydraulic pump, thereby improving the durability of the hydraulic pump that sucks hydraulic oil from the second storage portion.

[0009] In the present invention, it is preferable that the second storage section has a wall member that divides the interior of the second storage section into an upper region and a lower region, and a communication passage that connects the upper region and the lower region, and that the connecting oil passage is connected to the lower region.

[0010] According to the present invention, the interior of the second reservoir is divided into an upper region and a lower region by a wall member. Therefore, even if contaminants move from the upper region of the second reservoir through the connecting passage to the lower region, the contaminants are less likely to move from the lower region of the second reservoir to the upper region through the connecting passage. By connecting the connecting oil passage to the lower region of the second reservoir, contaminants are more likely to enter the connecting oil passage. This configuration is advantageous in that it reduces the amount of contaminants remaining in the second reservoir and improves the durability of the hydraulic pump that draws hydraulic oil from the second reservoir.

[0011] In the present invention, it is preferable that the communicating passage is provided near one of two sets of wall portions that face each other in the second storage section, and the portion of the connecting oil passage that is connected to the lower region is provided near the other of the two sets of wall portions that face each other in the second storage section.

[0012] According to the present invention, the connecting oil passage and the communication passage are provided near one wall portion and the other wall portion of the second reservoir, spaced apart from each other. Therefore, even if contaminants move from the upper region of the second reservoir through the communication passage to the lower region and move near the connecting oil passage, the contaminants are less likely to move from the lower region of the second reservoir through the communication passage to the upper region. This configuration is advantageous in that it reduces the amount of contaminants remaining in the second reservoir and improves the durability of the hydraulic pump that draws hydraulic oil from the second reservoir.

[0013] In the present invention, it is preferable that the second reservoir be provided with an oil supply section that can replenish hydraulic oil.

[0014] As described above, since the second reservoir is located higher than the first reservoir, the pressure of the hydraulic oil in the first reservoir is increased. In other words, the pressure of the hydraulic oil in the second reservoir is lower than the pressure of the hydraulic oil in the first reservoir. According to the present invention, the second reservoir is provided with an oil supply unit that can replenish the hydraulic oil. Therefore, when the hydraulic oil is replenished from the oil supply unit to the second reservoir, the pressure of the hydraulic oil in the second reservoir does not become a resistance, and the hydraulic oil is smoothly replenished from the oil supply unit to the second reservoir.

[0015] In the present invention, it is preferable that a first oil supply passage be provided to supply the hydraulic oil in the first reservoir to some of the plurality of working devices, and a second oil supply passage be provided to supply the hydraulic oil in the second reservoir to some of the plurality of working devices.

[0016] According to the present invention, in a work vehicle which often has multiple working devices provided in various sections, the first and second storage sections are provided at a distance from each other. The hydraulic oil from the first storage section is supplied via a first oil supply passage to a working device which, due to its positional relationship with the first storage section, is preferably supplied with hydraulic oil from the first storage section. The hydraulic oil from the second storage section is supplied via a second oil supply passage to a working device which, due to its positional relationship with the second storage section, is preferably supplied with hydraulic oil from the second storage section. This allows a work vehicle which often has multiple working devices provided in various sections to be configured so that hydraulic oil is efficiently supplied to the working devices in each section, thereby simplifying the hydraulic oil supply system to the working devices.

[0017] In the present invention, it is preferable that the second storage section has a wall member that divides the interior of the second storage section into an upper region and a lower region, and a communication passage that connects the upper region and the lower region, and that the second supply oil passage is connected to the upper region.

[0018] According to the present invention, the interior of the second reservoir is divided into an upper region and a lower region by a wall member. Therefore, when contaminants move from the upper region of the second reservoir through the connecting passage to the lower region, the contaminants are less likely to move from the lower region of the second reservoir through the connecting passage to the upper region. By connecting the second oil supply line to the upper region of the second reservoir, when hydraulic oil from the upper region of the second reservoir is drawn into the hydraulic pump, the amount of contaminants flowing into the hydraulic pump is reduced. This improves the durability of the hydraulic pump that draws hydraulic oil from the upper region of the second reservoir.

[0019] In the present invention, it is preferable that a first return oil passage be provided for returning hydraulic oil from some of the plurality of working devices to the first reservoir, and a second return oil passage be provided for returning hydraulic oil from some of the plurality of working devices to the second reservoir.

[0020] According to the present invention, in a work vehicle that often has multiple working devices provided in various sections, a first reservoir and a second reservoir are provided separately. Due to their positional relationship with the first reservoir, hydraulic oil from a working device that is preferably returned to the first reservoir is returned to the first reservoir via a first return oil passage. Due to their positional relationship with the second reservoir, hydraulic oil from a working device that is preferably returned to the second reservoir is returned to the second reservoir via a second return oil passage.

[0021] This allows the hydraulic oil from each working device in a work vehicle, which often has multiple working devices installed in different parts, to be efficiently returned, thereby simplifying the return system for the hydraulic oil of the working devices.

[0022] In the present invention, it is preferable that the system is provided with a first supply oil passage that supplies the hydraulic oil in the first reservoir to some of the working devices among the plurality of working devices, a second supply oil passage that supplies the hydraulic oil in the second reservoir to some of the working devices among the plurality of working devices, a first return oil passage that returns the hydraulic oil coming out of some of the working devices among the plurality of working devices to the first reservoir, and a second return oil passage that returns the hydraulic oil coming out of some of the working devices among the plurality of working devices to the second reservoir, and that the system includes the working device to which the hydraulic oil is supplied from the first supply oil passage and which outputs the hydraulic oil to the first return oil passage, and the working device to which the hydraulic oil is supplied from the second supply oil passage and which outputs the hydraulic oil to the second return oil passage.

[0023] According to the present invention, in a work vehicle which often has multiple working devices provided in various sections, a first reservoir and a second reservoir are provided separately. The hydraulic oil in the first reservoir is supplied via a first supply oil passage to a working device which, due to its positional relationship with the first reservoir, is preferably supplied with hydraulic oil from the first reservoir. The hydraulic oil in the second reservoir is supplied via a second supply oil passage to a working device which, due to its positional relationship with the second reservoir, is preferably supplied with hydraulic oil from the second reservoir. Due to its positional relationship with the first reservoir, hydraulic oil flowing out of a working device which, due to its positional relationship with the first reservoir, is preferably returned to the first reservoir via a first return oil passage. Due to its positional relationship with the second reservoir, hydraulic oil flowing out of a working device which, due to its positional relationship with the second reservoir, is preferably returned to the second reservoir via a second return oil passage. For a working device which, due to its positional relationship with the first reservoir, is preferably supplied with hydraulic oil from the first reservoir, it may be preferable for hydraulic oil flowing out of the working device to be returned to the first reservoir. According to the present invention, hydraulic oil from the first reservoir is supplied to the aforementioned working device via the first supply oil passage, and hydraulic oil discharged from the working device is returned to the first reservoir via the first return oil passage. For working devices that are preferably supplied with hydraulic oil from the second reservoir due to their positional relationship with the second reservoir, it may be preferable for hydraulic oil discharged from the working device to be returned to the second reservoir. According to the present invention, hydraulic oil from the second reservoir is supplied to the aforementioned working device via the second supply oil passage, and hydraulic oil discharged from the working device is returned to the second reservoir via the second return oil passage. This allows a work vehicle that often has multiple working devices installed in various locations to be configured so that hydraulic oil is efficiently supplied to the working devices in each location, and so that hydraulic oil discharged from the working devices in each location can be efficiently returned. This simplifies the hydraulic oil supply and return systems for the working devices.

[0024] In the present invention, it is preferable that the first storage section has a partition member that divides the interior of the first storage section into a first region and a second region, and a strainer through which hydraulic oil from the second region can pass and enter the first region, and that the first supply oil passage is connected to the first region, and the connecting oil passage and the first return oil passage are connected to the second region.

[0025] According to the present invention, the interior of the first reservoir is divided into a first region and a second region by a partition member, and the first region and the second region are connected by a strainer. Hydraulic oil and contaminants from the second reservoir enter the second region of the first reservoir through a connecting oil passage. Hydraulic oil and contaminants for the working device enter the second region of the first reservoir through a first return oil passage. Hydraulic oil from the second region of the first reservoir enters the first region through the strainer and is supplied from the first region to the working device through the first supply oil passage. This configuration prevents contaminants from entering the first supply oil passage, so when hydraulic oil from the first reservoir is drawn into the hydraulic pump, less contaminants flow into the hydraulic pump. This configuration is advantageous in terms of improving the durability of the hydraulic pump that draws hydraulic oil from the first reservoir. According to the present invention, when multiple first oil supply passages are provided, the first region of the first storage portion is configured to have an appropriate volume, so that the multiple first oil supply passages can be easily connected to the first region of the first storage portion. According to the present invention, hydraulic oil that enters the first region from the second region of the first storage portion through the strainer is distributed to the multiple first oil supply passages in the first region of the first storage portion. This allows for a small number of strainers to accommodate the multiple first oil supply passages, and eliminates the need to provide a strainer for each of the multiple first oil supply passages. This simplifies the structure of the first storage portion, as the multiple first oil supply passages can be easily connected to the first region of the first storage portion and the multiple first oil supply passages can be accommodated with a small number of strainers.

[0026] In the present invention, it is preferable that the first area is provided at the upper part of the interior of the first storage section, and the strainer is connected to the lower part of the first area and extends downward from the lower part of the first area.

[0027] According to the present invention, the first region of the first storage section and the strainer are compactly accommodated side by side in the vertical direction inside the first storage section, which is advantageous in terms of simplifying the structure of the first storage section.

[0028] In the present invention, it is preferable that the first region is provided in one of the left-right directions or one of the front-to-rear directions at the upper part of the interior of the first storage section, and that the connecting oil passage is connected to a portion of the second region adjacent to the first region.

[0029] According to the present invention, the connecting oil passage and the first region of the first storage section are compactly accommodated side by side along the left-right or front-to-back direction inside the first storage section, which is advantageous in terms of simplifying the structure of the first storage section.

[0030] In the present invention, it is preferable that the working device is supplied with hydraulic oil from the first supply oil passage and outputs the hydraulic oil to the second return oil passage.

[0031] In a work vehicle, due to the positional relationship between the first and second reservoirs, in a work device where it is preferable to supply hydraulic oil from the first reservoir, it may be preferable to return hydraulic oil from the work device to the second reservoir. According to the present invention, hydraulic oil from the first reservoir is supplied to the work device as described above via the first supply oil passage, and hydraulic oil from the work device is returned to the second reservoir via the second return oil passage. This is advantageous in terms of simplifying the hydraulic oil supply system and return system of the work device.

[0032] In the present invention, it is preferable that the working device is supplied with hydraulic oil from the second supply oil passage and outputs hydraulic oil to the first return oil passage.

[0033] In a work vehicle, due to the positional relationship between the first and second storage portions, in a work device where it is preferable to supply hydraulic oil from the second storage portion, it may be preferable to return hydraulic oil from the work device to the first storage portion. According to the present invention, hydraulic oil from the second storage portion is supplied to the work device as described above via the second supply oil passage, and hydraulic oil from the work device is returned to the first storage portion via the first return oil passage. This is advantageous in terms of simplifying the hydraulic oil supply system and return system of the work device.

[0034] In the present invention, it is preferable that the second storage section has a wall member that divides the interior of the second storage section into an upper region and a lower region, a communication passage that connects the upper region and the lower region, and includes the second return oil passage that is connected to the lower region.

[0035] According to the present invention, the interior of the second reservoir is divided into an upper region and a lower region by a wall member. Therefore, even if contaminants move from the upper region of the second reservoir through the connecting passage to the lower region, the contaminants are less likely to move from the lower region of the second reservoir to the upper region through the connecting passage. When hydraulic oil from the working device is returned to the second reservoir via the second return oil passage, the inclusion of the second return oil passage connected to the lower region of the second reservoir reduces the likelihood of contaminants generated in the working device entering the upper region of the second reservoir. As a result, when hydraulic oil from the upper region of the second reservoir is drawn into the hydraulic pump, less contaminants flow into the hydraulic pump, thereby improving the durability of the hydraulic pump that draws hydraulic oil from the upper region of the second reservoir.

[0036] In the present invention, it is preferable that upper and lower pipe members are provided that connect the upper part of the second storage section and the lower part, passing through the upper part, and that the second return oil passage connected to the lower part is connected to the upper and lower pipe members.

[0037] Depending on the positional relationship between the second reservoir and the second return oil passage, it may be difficult to directly connect the second return oil passage to the lower region of the second reservoir. According to the present invention, the upper and lower pipe members penetrate the upper region of the second reservoir and connect the upper and lower regions of the second reservoir. By connecting the second return oil passage to the upper and lower pipe members, when it is difficult to directly connect the second return oil passage to the lower region of the second reservoir, the second return oil passage is smoothly connected to the lower region of the second reservoir via the upper and lower pipe members. This allows for a configuration in which hydraulic oil from the working devices is efficiently returned to the lower region of the second reservoir in a work vehicle that often has multiple working devices installed in various parts, which is advantageous in terms of simplifying the return system for hydraulic oil of the working devices.

[0038] In the present invention, it is preferable that the communicating passage is provided near one of two sets of wall portions facing each other in the second storage section, a horizontal pipe member is provided extending from one of the two sets of wall portions facing each other in the second storage section across the communicating passage to the lower region, and the second return oil passage connected to the lower region is connected to the horizontal pipe member.

[0039] Depending on the positional relationship between the second reservoir and the second return oil passage, it may be difficult to directly connect the second return oil passage to the lower region of the second reservoir. According to the present invention, the horizontal pipe member extends from the wall portion of the second reservoir on the side of the connecting passage, across the connecting passage, to the lower region of the second reservoir. By connecting the second return oil passage to the horizontal pipe member, when it is difficult to directly connect the second return oil passage to the lower region of the second reservoir, the second return oil passage is smoothly connected to the lower region of the second reservoir via the horizontal pipe member. This allows for a configuration in which hydraulic oil from the working devices is efficiently returned to the lower region of the second reservoir in a work vehicle that often has multiple working devices installed in various locations, which is advantageous in terms of simplifying the return system for hydraulic oil for the working devices. According to the present invention, the horizontal pipe member crosses the connecting passage of the second reservoir. Therefore, when contaminants move from the upper region of the second reservoir through the communicating passage to the lower region as described above, the horizontal pipe member further prevents the contaminants from moving from the lower region of the second reservoir through the communicating passage to the upper region. As a result, when hydraulic oil in the upper region of the second reservoir is drawn into the hydraulic pump, less contaminants flow into the hydraulic pump, which is advantageous in terms of improving the durability of the hydraulic pump that draws hydraulic oil from the upper region of the second reservoir.

[0040] In the present invention, the second storage section preferably has a wall member that divides the interior of the second storage section into an upper region and a lower region, a communication passage that connects the upper region and the lower region, includes the second return oil passage that is connected to the upper region, and is provided with a filter that allows the hydraulic oil in the second return oil passage that is connected to the upper region to pass through and be returned to the upper region.

[0041] According to the present invention, the interior of the second reservoir is divided into an upper region and a lower region by a wall member. Therefore, even if contaminants move from the upper region of the second reservoir to the lower region through the connecting passage, the contaminants are less likely to move from the lower region of the second reservoir to the upper region through the connecting passage. According to the present invention, when a second return oil passage is provided to return hydraulic oil from the working device to the second reservoir, the second return oil passage is included, which is connected to the upper region of the second tank. The hydraulic oil in this second return oil passage is returned to the upper region of the second reservoir through a filter. This allows the filter to reduce contaminants from entering the upper region of the second reservoir. Therefore, when hydraulic oil from the second reservoir is drawn into the hydraulic pump, less contaminants flow into the hydraulic pump, improving the durability of the hydraulic pump that draws hydraulic oil from the second reservoir.

[0042] In the present invention, it is preferable that the working device includes a hydrostatic continuously variable transmission that drives the traveling device.

[0043] According to the present invention, a configuration suitable for a work vehicle having a hydrostatic continuously variable transmission that drives a traveling device as a work device can be obtained.

[0044] In the present invention, it is preferable that the working device includes a conveying device that conveys and discharges the processed material to the outside.

[0045] According to the present invention, a configuration suitable for a work vehicle having a transport device as a work device for transporting and discharging materials to the outside can be obtained.

[0046] It is a left side view of the sugarcane harvester. It is a schematic diagram showing the whole of the hydraulic circuit. It is a longitudinal front view of the first tank and the second tank. It is a longitudinal left side view of the first tank and the second tank.

[0047] Figures 1 to 4 show a sugarcane harvester, which is an example of a work vehicle, and in Figures 1 to 4, F indicates the forward direction, B indicates the backward direction, U indicates the upward direction, D indicates the downward direction, R indicates the right direction, and L indicates the left direction.

[0048] (Overall structure of the sugarcane harvester) As shown in Figure 1, the cutting unit 3 (corresponding to the working device) and the first conveying device 4 (corresponding to the working device) are connected to form the machine body 13, and the first conveying device 4 extends diagonally upward and rearward from the rear of the cutting unit 3.

[0049] Right and left front wheels 1 are attached to the right and left parts of the reaping unit 3. An upper cutting device 7 (corresponding to a working device) is provided on the top of the reaping unit 3 and is arranged so as to be located above and in front of the reaping unit 3. Right and left rear wheels 2 (corresponding to a traveling device) are provided on the lower part of the rear part of the first conveying device 4, and the front wheels 1 and rear wheels 2 support the machine body 13.

[0050] A sorting device 5 (corresponding to a working device) is provided at the rear of the first conveying device 4 along the vertical direction, and a second conveying device 6 (corresponding to a conveying device) (corresponding to a working device) extends diagonally upward from the bottom of the sorting device 5. A driving unit 9 is provided at the top of the reaping unit 3, and an engine 10 is provided at the top of the front part of the first conveying device 4.

[0051] (Operating state of sugarcane harvester) As shown in Figure 1, as the machine body 13 moves forward, the upper leaves of the crops in the field are cut by the upper cutting device 7, and the crops in the field are introduced into the cutting unit 3. The crops introduced into the cutting unit 3 are leaned forward, the bases of the plants are cut, and the crops are supplied from the bases to the first conveying device 4. The crops supplied to the first conveying device 4 are transported diagonally upward and rearward along the first conveying device 4, cut to a predetermined length at the rear end of the first conveying device 4, and supplied to the top of the sorting device 5.

[0052] The crops supplied to the top of the sorting device 5 fall into the front part of the second conveying device 6. A sorting fan 5a (see FIG. 2) is provided at the top of the sorting device 5, and sorting air from the sorting fan 5a is generated in an upward direction inside the sorting device 5. Inside the sorting device 5, the crops fall into the front part of the second conveying device 6 below, and impurities are separated from the crops by the sorting air and discharged from the top of the sorting device 5.

[0053] The crops that have fallen onto the front of the second conveying device 6 are transported diagonally upward by the second conveying device 6. A transport vehicle (not shown) accompanies the sugarcane harvester, and the crops are dumped from the rear of the second conveying device 6 onto the bed of the transport vehicle.

[0054] (Outline of Hydraulic System in Sugarcane Harvester) As shown in FIG. 2, hydraulic pumps 23, 24, 25, 26, 27, 28, and 29 driven by the engine 10 (see FIG. 1) are provided.

[0055] A steering device 17 (corresponding to a working device) is provided to steer the front wheels 1. When a control handle (not shown) provided on the driving section 9 is operated, the front wheels 1 are steered by the steering device 17.

[0056] The vehicle 13 is provided with a hydrostatic continuously variable transmission 8 (corresponding to a working device), and the hydrostatic continuously variable transmission 8 drives the rear wheels 2 (see FIG. 1 ), causing the vehicle body 13 to move forward and backward. The hydrostatic continuously variable transmission 8 has a hydraulic pump 8a, a hydraulic motor 8b, and a charge pump 8c (corresponding to a hydraulic pump), and the hydraulic pump 8a and charge pump 8c of the hydrostatic continuously variable transmission 8 are driven by an engine 10 (see FIG. 1 ).

[0057] There are provided hydraulic cylinders (not shown) for raising and lowering the second conveying device 6 and changing its direction, hydraulic cylinders (not shown) for raising and lowering the front wheels 1, and hydraulic cylinders (not shown) for raising and lowering the upper cutting device 7, and these hydraulic cylinders are provided with control valve units 18 (corresponding to working devices) for supplying and discharging hydraulic oil.

[0058] 1 and 2, a radiator 30 and three oil coolers 20, 21, and 22 are provided in the upper rear portion of the first transfer device 4. A blower fan 19 (corresponding to a working device) that supplies cooling air to the radiator 30 and the oil coolers 20, 21, and 22 is provided in the upper rear portion of the first transfer device 4.

[0059] The harvesting unit 3, first conveying device 4, sorting device 5 (sorting fan 5a), second conveying device 6, upper cutting device 7, hydrostatic continuously variable transmission 8, steering device 17, control valve unit 18, blower fan 19, etc. are configured to be hydraulically operated by hydraulic oil supplied from the first tank 11 (corresponding to the first storage section) and the second tank 12 (corresponding to the second storage section) described below by hydraulic pumps 23 to 29 and the charge pump 8c of the hydrostatic continuously variable transmission 8.

[0060] (Configuration of first tank 11) As shown in Figure 1, the first tank 11 is provided on the left side of the front part of the first conveying device 4 (rear part of the cutting unit 3), between the left front wheel 1 and the left rear wheel 2, and hydraulic oil is stored in the first tank 11.

[0061] 3 and 4, the first tank 11 is configured in a box shape having a ceiling 11a, a right wall 11b, a left wall 11c, a front wall 11d, a rear wall 11e, and a bottom 11f. Inside the first tank 11, a flat partition member 11g is attached across the ceiling 11a, the left wall 11c, and the rear wall 11e, and a first region 11h and a second region 11j are provided, separated by the partition member 11g.

[0062] The first region 11h is provided in the upper left portion of the interior of the first tank 11. Two strainers 14 are attached to the lower portion of the partition member 11g side by side in the front-to-rear direction and extend from the lower portion of the partition member 11g downward toward the bottom portion 11f.

[0063] 1, the second tank 12 is provided on the left side of the rear (upper) part of the first conveying device 4, and hydraulic oil is stored in the second tank 12. The second tank 12 is configured to have a smaller volume than the first tank 11. The second tank 12 is provided at a position higher than the ceiling part 11a of the first tank 11, and is provided behind the first tank 11.

[0064] As shown in Figures 3 and 4, the second tank 12 is configured in a box shape having a ceiling portion 12a, a right wall portion 12b (corresponding to a wall portion), a left wall portion 12c (corresponding to a wall portion), a front wall portion 12d, a rear wall portion 12e, and a bottom portion 12f.

[0065] Inside the second tank 12, a wall member 12g is attached across the left wall portion 12c, the front wall portion 12d, and the rear wall portion 12e, providing an upper region 12h and a lower region 12j separated by the wall member 12g. A communication passage 12k is provided between the right wall portion 12b and the right end of the wall member 12g, and the upper region 12h and the lower region 12j communicate with each other via the communication passage 12k.

[0066] A filter 15 is disposed in an upper region 12h of the second tank 12 and attached to the ceiling portion 12a of the second tank 12. An oil supply portion 12m of the second tank 12 is provided on the upper left portion of the rear wall portion 12e, and hydraulic oil is supplied from the oil supply portion 12m of the second tank 12 to the upper region 12h.

[0067] The upper and lower pipe members 31 are attached across the ceiling portion 12a and wall member 12g of the second tank 12 and through the upper region 12h of the second tank 12, and the lower portions of the upper and lower pipe members 31 are connected to the lower region 12j of the second tank 12.

[0068] The horizontal pipe member 32 is attached to the right wall portion 12b of the second tank 12, passes through the communication passage 12k from the right wall portion 12b of the second tank 12, and enters the inside of the lower region 12j. An end of the horizontal pipe member 32 is located near the center of the left and right of the lower region 12j of the second tank 12.

[0069] (Configuration of Connection Oil Passage 16) As shown in Figs. 3 and 4, the connection oil passage 16, through which hydraulic oil can be communicated, connects the first tank 11 and the second tank 12.

[0070] An upper portion 16a of the connecting oil passage 16 is attached to the left portion of the bottom portion 12f of the second tank 12, and is connected to the vicinity of the left wall portion 12c of the lower region 12j of the second tank 12. A lower portion 16b of the connecting oil passage 16 is attached to the right portion of the upper portion of the rear wall portion 11e of the first tank 11, and is connected to the second region 11j of the first tank 11. The lower portion 16b of the connecting oil passage 16 is connected to a portion of the upper portion of the second region 11j of the first tank 11 that is adjacent to the first region 11h, and the first region 11h of the first tank 11 and the lower portion 16b of the connecting oil passage 16 are arranged side by side in the left-right direction.

[0071] The hydraulic oil in the upper region 12h of the second tank 12 passes from the upper region 12h of the second tank 12 through the communication passage 12k and the lower region 12j to enter the connecting oil passage 16, and can then pass through the connecting oil passage 16 to enter the second region 11j of the first tank 11. Under normal conditions, hydraulic oil is poured into the second tank 12 until the liquid level of the hydraulic oil is located near the ceiling portion 12a of the second tank 12, and the first tank 11 is full of hydraulic oil.

[0072] (Configuration of the hydraulic circuit of the cutting unit 3) As shown in Figures 2, 3, and 4, the oil passage 33 (corresponding to the first supply oil passage) is connected to the ceiling portion 11a of the first tank 11 and connected to the first region 11h, and is connected from the first tank 11 to the hydraulic pump 23, and from the hydraulic pump 23 to the cutting unit 3.

[0073] An oil passage 43 (corresponding to the second return oil passage) is connected to the cutting section 3, from the cutting section 3 to the oil cooler 20, from the oil cooler 20 to the filter 15 of the second tank 12, and to the upper region 12h of the second tank 12.

[0074] The hydraulic oil in the second area 11j of the first tank 11 passes through the strainer 14 into the first area 11h of the first tank 11, is sucked into the hydraulic pump 23 through the oil passage 33, and the hydraulic oil in the hydraulic pump 23 is supplied to the cutting unit 3 through the oil passage 33, causing the cutting unit 3 to operate.

[0075] The hydraulic oil that operates the cutting unit 3 leaves the cutting unit 3 and is supplied to the oil cooler 20 through the oil passage 43, and then returns from the oil cooler 20 through the oil passage 43 and the filter 15 to the upper region 12h of the second tank 12.

[0076] (Configuration of hydraulic circuit of first conveying device 4) As shown in Figures 2, 3, and 4, an oil passage 34 (corresponding to a first supply oil passage) is connected to the ceiling portion 11a of the first tank 11 and connected to the first region 11h, and is connected from the first tank 11 to the hydraulic pump 24, and from the hydraulic pump 24 to the first conveying device 4.

[0077] An oil passage 44 (corresponding to the second return oil passage) is connected to the first conveying device 4, from the first conveying device 4 to the oil cooler 21, from the oil cooler 21 to the filter 15 of the second tank 12, and to the upper region 12h of the second tank 12.

[0078] An oil passage 50 (corresponding to the second return oil passage) is connected to the first conveying device 4, and is connected from the first conveying device 4 to the horizontal pipe member 32 of the second tank 12, and is connected to the lower region 12j of the second tank 12.

[0079] The hydraulic oil in the second region 11j of the first tank 11 passes through the strainer 14 into the first region 11h of the first tank 11, is sucked into the hydraulic pump 24 through the oil passage 34, and the hydraulic oil in the hydraulic pump 24 is supplied to the first conveying device 4 through the oil passage 34, causing the first conveying device 4 to operate.

[0080] The hydraulic oil that has operated the first conveying device 4 leaves the first conveying device 4 and is supplied to the oil cooler 21 through the oil passage 44, and returns from the oil cooler 21 to the upper region 12h of the second tank 12 through the oil passage 44 and the filter 15. Hydraulic oil that leaks during operation of the first conveying device 4 passes through the oil passage 50 and returns to the lower region 12j of the second tank 12 from the horizontal pipe member 32.

[0081] (Configuration of the hydraulic circuit of the sorting device 5) As shown in Figures 2, 3, and 4, the oil passage 35 (corresponding to the first supply oil passage) is connected to the ceiling portion 11a of the first tank 11 and connected to the first region 11h, and is connected from the first tank 11 to the hydraulic pump 25, and from the hydraulic pump 25 to the sorting device 5 (sorting fan 5a).

[0082] An oil passage 45 (corresponding to the second return oil passage) is connected to the sorting device 5 (sorting fan 5a), from the sorting device 5 (sorting fan 5a) to the oil cooler 22, from the oil cooler 22 to the filter 15 of the second tank 12, and to the upper region 12h of the second tank 12.

[0083] The hydraulic oil in the second area 11j of the first tank 11 passes through the strainer 14 and enters the first area 11h of the first tank 11, and is sucked into the hydraulic pump 25 through the oil passage 35. The hydraulic oil in the hydraulic pump 25 is supplied to the sorting device 5 through the oil passage 35, and the sorting fan 5a of the sorting device 5 operates.

[0084] The hydraulic oil that operates the sorting fan 5a of the sorting device 5 leaves the sorting device 5 and is supplied to the oil cooler 22 through the oil passage 45, and then returns from the oil cooler 22 through the oil passage 45 and the filter 15 to the upper region 12h of the second tank 12.

[0085] (Configuration of hydraulic circuits of upper cutting device 7 and steering device 17) As shown in Figures 2, 3, and 4, an oil passage 37 (corresponding to a first supply oil passage) is connected to the ceiling portion 11a of the first tank 11 and connected to the first region 11h, is connected from the first tank 11 to the hydraulic pump 27, is connected from the hydraulic pump 27 to the steering device 17, and is connected from the steering device 17 to the upper cutting device 7.

[0086] An oil passage 47 (corresponding to the first return oil passage) is connected to the upper cutting device 7 and the steering device 17, and the two oil passages 47 merge and connect to the upper part of the right wall portion 11b of the first tank 11, and are connected to the second region 11j of the first tank 11.

[0087] The hydraulic oil in the second area 11j of the first tank 11 passes through the strainer 14 into the first area 11h of the first tank 11, is sucked into the hydraulic pump 27 through the oil passage 37, and the hydraulic oil in the hydraulic pump 27 is supplied to the upper cutting device 7 and the steering device 17 through the oil passage 37, thereby operating the upper cutting device 7 and the steering device 17.

[0088] The hydraulic oil that has operated the upper cutting device 7 and the steering device 17 leaves the upper cutting device 7 and the steering device 17 and passes through the oil passage 47 to return to the second region 11 j of the first tank 11 .

[0089] (Configuration of hydraulic circuit of blower fan 19) As shown in Figures 2, 3, and 4, an oil passage 39 (corresponding to a first supply oil passage) is connected to the ceiling portion 11a of the first tank 11 and connected to the first region 11h, and is connected from the first tank 11 to the hydraulic pump 29, and from the hydraulic pump 29 to the blower fan 19.

[0090] An oil passage 49 (corresponding to the second return oil passage) is connected to the blower fan 19, and from the blower fan 19 to the upper and lower pipe members 31 of the second tank 12, and is connected to the lower region 12j of the second tank 12.

[0091] The hydraulic oil in the second region 11j of the first tank 11 passes through the strainer 14 and enters the first region 11h of the first tank 11, and is sucked into the hydraulic pump 29 through the oil passage 39. The hydraulic oil in the hydraulic pump 29 is supplied to the blower fan 19 through the oil passage 39, thereby operating the blower fan 19. The hydraulic oil that has operated the blower fan 19 leaves the blower fan 19 and returns to the lower region 12j of the second tank 12 through the oil passage 49 and the upper and lower pipe members 31 of the second tank 12.

[0092] (Configuration of the hydraulic circuit of the second conveying device 6) As shown in Figures 2, 3, and 4, an oil passage 36 (corresponding to the second supply oil passage) is connected to the front wall portion 12d of the second tank 12 and connected to the upper region 12h, and is connected from the second tank 12 to the hydraulic pump 26, and from the hydraulic pump 26 to the second conveying device 6.

[0093] An oil passage 46 (corresponding to the second return oil passage) is connected to the second conveying device 6, and from the second conveying device 6 to the upper and lower pipe members 31 of the second tank 12, and is connected to the lower region 12j of the second tank 12.

[0094] The hydraulic oil in the upper region 12h of the second tank 12 is sucked into the hydraulic pump 26 through the oil passage 36, and the hydraulic oil in the hydraulic pump 26 is supplied to the second conveying device 6 through the oil passage 36, thereby operating the second conveying device 6. The hydraulic oil that has operated the second conveying device 6 leaves the second conveying device 6 and returns to the lower region 12j of the second tank 12 through the oil passage 46 and the upper and lower pipe members 31 of the second tank 12.

[0095] (Configuration of hydraulic circuit of control valve unit 18) As shown in Figures 2, 3, and 4, an oil passage 38 (corresponding to a second supply oil passage) is connected to the front wall portion 12d of the second tank 12 and then to the upper region 12h, and is connected from the second tank 12 to the hydraulic pump 28, and from the hydraulic pump 28 to the control valve unit 18.

[0096] An oil passage 48 (corresponding to the first return oil passage) is connected to the control valve unit 18, and is connected from the control valve unit 18 to the upper part of the rear wall portion 11e of the first tank 11, and is connected to the second region 11j of the first tank 11.

[0097] The hydraulic oil in the upper region 12h of the second tank 12 is sucked into the hydraulic pump 28 through the oil passage 38, and the hydraulic oil in the hydraulic pump 28 is supplied to the control valve unit 18 through the oil passage 38, thereby operating the control valve unit 18. The hydraulic oil that has operated the control valve unit 18 leaves the control valve unit 18 and returns to the second region 11j of the first tank 11 through the oil passage 48.

[0098] (Configuration of Hydraulic Circuit of Hydrostatic Continuously Variable Transmission 8) As shown in FIGS. 2, 3, and 4, an oil passage 40 (corresponding to a second oil supply passage) is connected to the front wall portion 12d of the second tank 12 and then to the upper region 12h, and is connected from the second tank 12 to the charge pump 8c of the hydrostatic continuously variable transmission 8.

[0099] An oil passage 51 (corresponding to the second return oil passage) is connected to the hydraulic pump 8a of the hydrostatic continuously variable transmission 8, and is connected from the hydraulic pump 8a of the hydrostatic continuously variable transmission 8 to the front wall portion 12d of the second tank 12, and is connected to the lower region 12j of the second tank 12.

[0100] An oil passage 52 (corresponding to the second return oil passage) is connected to the hydraulic motor 8b of the hydrostatic continuously variable transmission 8, and is connected from the hydraulic motor 8b of the hydrostatic continuously variable transmission 8 to the rear wall portion 12e of the second tank 12, and is connected to the lower region 12j of the second tank 12.

[0101] The hydraulic oil in the upper region 12h of the second tank 12 passes through the oil passage 40 and is sucked into the charge pump 8c of the hydrostatic continuously variable transmission 8, and is supplied from the charge pump 8c of the hydrostatic continuously variable transmission 8 to the hydraulic pump 8a and hydraulic motor 8b of the hydrostatic continuously variable transmission 8.

[0102] When the hydrostatic continuously variable transmission 8 is in operation, hydraulic oil leaking from the hydraulic pump 8 a and hydraulic motor 8 b of the hydrostatic continuously variable transmission 8 passes through the oil passages 51 and 52 and returns to the lower region 12 j of the second tank 12 .

[0103] (First Alternative Embodiment of the Invention) A plurality of second tanks 12, such as two or three, may be provided. In this configuration, the connecting oil passage 16 may be configured to extend from each of the plurality of second tanks 12 and connect to the first tank 11. When a plurality of second tanks 12 are provided, the second tanks 12 do not all have to be provided at the same height, and the heights of the plurality of second tanks 12 may be configured to be different from one another.

[0104] (Second Alternative Embodiment of the Invention) A plurality of first tanks 11, such as two or three, may be provided. In this configuration, oil passages (not shown) may be connected across adjacent first tanks 11, so that all of the first tanks 11 communicate with each other. When a plurality of first tanks 11 are provided, the first tanks 11 do not all have to be provided at the same height, and the heights of the plurality of first tanks 11 may be configured to be different from each other.

[0105] (Third Alternative Embodiment of the Invention) A plurality of connecting oil passages 16 may be configured to extend from one second tank 12 and connect to one first tank 11. A plurality of connecting oil passages 16 may be configured to extend from one second tank 12 and connect to each of a plurality of first tanks 11.

[0106] (Fourth Alternative Embodiment of the Invention) Inside the second tank 12, a wall member 12g may be attached across the right wall portion 12b, the front wall portion 12d, and the rear wall portion 12e, and a communication passage 12k may be provided between the left wall portion 12c and the left end of the wall member 12g. In this configuration, the horizontal pipe member 32 may be configured to pass from the left wall portion 12c of the second tank 12 through the communication passage 12k and enter the inside of the lower region 12j.

[0107] (Fifth Alternative Embodiment of the Invention) A plurality of communication passages 12k may be provided inside the second tank 12. According to this configuration, one of the plurality of communication passages 12k may be provided in the center of the wall member 12g.

[0108] (Sixth alternative embodiment of the invention) When the first region 11h of the first tank 11 is provided in the upper left part of the interior of the first tank 11, the lower part 16b of the connecting oil passage 16 may be attached to the right part of the ceiling part 11a of the first tank 11, or to the upper part of the right wall part 11b of the first tank 11, or to the upper part of the right part of the front wall part 11d of the first tank 11.

[0109] (Seventh Alternative Embodiment of the Invention) The first region 11h of the first tank 11 may be provided along the front-to-rear direction in the right part of the upper part of the interior of the first tank 11. According to this configuration, the lower part 16b of the connecting oil passage 16 may be attached to the left part of the ceiling part 11a of the first tank 11, to the upper part of the left wall part 11c of the first tank 11, or to the upper part of the left part of the front wall part 11d of the first tank 11.

[0110] Eighth Alternative Embodiment of the Invention The first region 11h of the first tank 11 may be provided along the left-right direction in the rear portion of the upper part of the interior of the first tank 11. According to this configuration, the lower part 16b of the connecting oil passage 16 may be attached to the front part of the ceiling part 11a of the first tank 11, to the front part of the upper part of the right wall part 11b of the first tank 11, or to the front part of the upper part of the left wall part 11c of the first tank 11.

[0111] (Ninth Alternative Embodiment of the Invention) The first region 11h of the first tank 11 may be provided along the left-right direction in the front part of the upper part of the interior of the first tank 11. According to this configuration, the lower part 16b of the connecting oil passage 16 may be attached to the rear part of the ceiling part 11a of the first tank 11, or may be attached to the rear part of the upper part of the right wall part 11b of the first tank 11, or may be attached to the rear part of the upper part of the left wall part 11c of the first tank 11.

[0112] (Tenth alternative embodiment of the invention) The sugarcane harvester is equipped with a cutting section 3, a first conveying device 4, a sorting device 5 (sorting fan 5a), a second conveying device 6, an upper cutting device 7, a hydrostatic continuously variable transmission 8, a steering device 17, a control valve unit 18, a blower fan 19, etc. as working devices.

[0113] In this case, which working device is to be connected to the first supply oil passage and the first return oil passage can be set and changed arbitrarily, and the working device to which the first supply oil passage and the first return oil passage are connected may be abolished.

[0114] Which working device is to be connected to the second supply oil passage and the second return oil passage can be set and changed arbitrarily, and the working device to which the second supply oil passage and the second return oil passage are connected may be eliminated.

[0115] Which working device is to be connected to the first supply oil passage and the second return oil passage can be set and changed arbitrarily, and the working device to which the first supply oil passage and the second return oil passage are connected may be eliminated.

[0116] Which working device is to be connected to the second supply oil passage and the first return oil passage can be set and changed arbitrarily, and the working device to which the second supply oil passage and the first return oil passage are connected may be eliminated.

[0117] (Correspondence to claims) -1 A plurality of working devices (a reaping unit 3, a first conveying device 4, a sorting device 5 (sorting fan 5a), a second conveying device 6, an upper cutting device 7, a hydrostatic continuously variable transmission 8, a steering device 17, a control valve unit 18, and a blower fan 19) are provided.

[0118] The hydraulic system includes a first reservoir (first tank 11) capable of storing hydraulic oil, and a second reservoir (second tank 12) capable of storing hydraulic oil. Hydraulic pumps 23, 24, 25, 26, 27, 28, and 29 (charge pump 8c) are provided to supply hydraulic oil to the working device.

[0119] The second storage section (second tank 12) is provided at a position higher than the upper end of the first storage section (first tank 11). A connecting oil passage 16 is provided that connects the first storage section (first tank 11) and the second storage section (second tank 12) and allows hydraulic oil to communicate between them. The connecting oil passage 16 connects the upper part of the first storage section (first tank 11) and the lower part of the second storage section (second tank 12).

[0120] (Correspondence to claims) - 2 A first supply oil passage (oil passages 33, 34, 35, 37, 39) is provided to supply hydraulic oil from the first storage section (first tank 11) to some of the multiple work devices (the cutting section 3, the first conveying device 4, the sorting device 5 (sorting fan 5a), the upper cutting device 7, the steering device 17, and the blower fan 19).

[0121] A second oil supply passage (oil passages 36, 38, 40) is provided to supply hydraulic oil from the second reservoir (second tank 12) to some of the multiple working devices (second conveying device 6, hydrostatic continuously variable transmission device 8, control valve unit 18).

[0122] A first return oil passage (oil passages 47, 48) is provided to return hydraulic oil coming out of some of the multiple work devices (upper cutting device 7, steering device 17, control valve unit 18) to the first reservoir (first tank 11).

[0123] A second return oil passage (oil passages 43, 44, 45, 46, 49, 50, 51, 52) is provided to return hydraulic oil coming out of some of the multiple working devices (the cutting unit 3, the first conveying device 4, the sorting device 5 (sorting fan 5a), the second conveying device 6, the hydrostatic continuously variable transmission 8, the blower fan 19) to the second storage unit (second tank 12).

[0124] (Correspondence to claims) -3 The system includes working devices (upper cutting device 7, steering device 17) that receive hydraulic oil from a first supply oil passage (oil passage 37) and send the hydraulic oil to a first return oil passage (oil passage 47). The system includes working devices (second conveying device 6, hydrostatic continuously variable transmission 8) that receive hydraulic oil from a second supply oil passage (oil passages 36, 40) and send the hydraulic oil to a second return oil passage (oil passages 46, 51, 52).

[0125] The system includes working devices (reaper 3, first conveying device 4, sorting device 5 (sorting fan 5a), blower fan 19) that receive hydraulic oil from a first supply oil passage (oil passages 33, 34, 35, 39) and discharge the hydraulic oil to a second return oil passage (oil passages 43, 44, 45, 49). The system also includes a working device (control valve unit 18) that receives hydraulic oil from a second supply oil passage (oil passage 38) and discharges the hydraulic oil to a first return oil passage (oil passage 48).

[0126] The work device includes a hydrostatic continuously variable transmission 8 that drives the traveling device (rear wheels 2). The work device also includes a conveying device (second conveying device 6) that conveys and discharges the processed material (crops) to the outside.

[0127] (Correspondence to Claims)-4 The first reservoir (first tank 11) has a partition member 11g that separates the interior of the first reservoir (first tank 11) into a first region 11h and a second region 11j, and a strainer 14 through which hydraulic oil from the second region 11j can pass and enter the first region 11h. A first supply oil passage (oil passages 33, 34, 35, 37, 39) is connected to the first region 11h. A connecting oil passage 16 and a first return oil passage (oil passages 47, 48) are connected to the second region 11j.

[0128] The first region 11h is provided in the upper part of the interior of the first storage section (first tank 11). The strainer 14 is connected to the lower part of the first region 11h and extends downward from the lower part of the first region 11h.

[0129] The first region 11h is provided on one side in the left-right direction or one side in the front-rear direction in the upper part of the interior of the first storage portion (first tank 11). The connecting oil passage 16 is connected to a portion of the second region 11j adjacent to the first region 11h.

[0130] (Correspondence to Claims)-5 The second reservoir (second tank 12) has a wall member 12g that separates the interior of the second reservoir (second tank 12) into an upper region 12h and a lower region 12j, and a communication passage 12k that connects the upper region 12h and the lower region 12j. A connecting oil passage 16 is connected to the lower region 12j.

[0131] The communication passage 12k is provided near one wall (right wall 12b) of two pairs of opposing walls (right wall 12b, left wall 12c) in the second storage section (second tank 12). The portion of the connecting oil passage 16 connected to the lower region 12j is provided near the other wall (left wall 12c) of two pairs of opposing walls (right wall 12b, left wall 12c) in the second storage section (second tank 12). The second storage section (second tank 12) is provided with an oil supply section 12m that can replenish hydraulic oil.

[0132] Second supply oil passages (oil passages 36, 38, 40) are connected to the upper region 12h. Second return oil passages (oil passages 46, 49, 50, 51, 52) are included which are connected to the lower region 12j.

[0133] An upper and lower pipe member 31 is provided between the upper and lower regions 12j of the second reservoir (second tank 12) and penetrates the upper region 12h to connect them. A second return oil passage (oil passages 46, 49) connected to the lower region 12j is connected to the upper and lower pipe member 31.

[0134] The second reservoir (second tank 12) includes a horizontal pipe member 32 extending from one of two opposing wall sections (right wall section 12b and left wall section 12c) (right wall section 12b) to a lower region 12j across the communication passage 12k. A second return oil passage (oil passage 50) connected to the lower region 12j is connected to the horizontal pipe member 32.

[0135] The upper region 12h includes second return oil passages (oil passages 43, 44, 45) connected to the upper region 12h. A filter 15 is provided to allow the hydraulic oil in the second return oil passages (oil passages 43, 44, 45) connected to the upper region 12h to pass and be returned to the upper region 12h.

[0136] The configurations disclosed in the above-described embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with the configurations disclosed in other embodiments, unless a contradiction occurs. Furthermore, the embodiments disclosed in this specification are merely examples, and the present invention is not limited to these, and can be modified as appropriate within the scope of the purpose of the present invention.

[0137] The present invention can be applied not only to sugarcane harvesters, but also to other agricultural work vehicles such as head-feeding combines and conventional combines, and construction work vehicles such as backhoes and front loaders, and can also be applied to work vehicles equipped with crawler-type traveling devices (not shown) instead of the rear wheels 2.

[0138] DESCRIPTION OF SYMBOLS 2 Rear wheel (traveling device) 3 Reaping unit (working device) 4 First conveying device (working device) 5 Sorting device (working device) 6 Second conveying device (working device) (conveying device) 8 Hydrostatic continuously variable transmission (working device) 8c Charge pump (hydraulic pump) 11 First tank (first storage section) 11g Partition member 11h First region 11j Second region 12 Second tank (second storage section) 12b Right wall section (wall section) 12c Left wall section (wall section) 12g Wall member 12h Upper region 12j Lower region 12k Communication passage 12m Oil supply section 14 Strainer 15 Filter 16 Connecting oil passage 17 Steering device (working device) 18 Control valve unit (working device) 19 Blower fan (working device) 23 Hydraulic pump 24 Hydraulic pump 25 Hydraulic pump 26 Hydraulic pump 27 Hydraulic pump 28 Hydraulic pump 29 Hydraulic pump 31 Upper and lower pipe member 32 Horizontal pipe member 33 Oil passage (first supply oil passage) 34 Oil passage (first supply oil passage) 35 Oil passage (first supply oil passage) 36 Oil passage (second supply oil passage) 37 Oil passage (first supply oil passage) 38 Oil passage (second supply oil passage) 39 Oil passage (first supply oil passage) 40 Oil passage (second supply oil passage) 43 Oil passage (second return oil passage) 44 Oil passage (second return oil passage) 45 Oil passage (second return oil passage) 46 Oil passage (second return oil passage) 47 Oil passage (first return oil passage) 48 Oil passage (first return oil passage) 49 Oil passage (second return oil passage) 50 Oil passage (second return oil passage) 51 Oil passage (second return oil passage) 52 Oil passage (second return oil passage)

Claims

1. A work vehicle equipped with a plurality of working devices, a first reservoir capable of storing hydraulic oil, a second reservoir capable of storing hydraulic oil, and a hydraulic pump that supplies hydraulic oil to the working devices, wherein the second reservoir is located at a higher position than the upper end of the first reservoir, and a connecting oil passage that connects the first reservoir and the second reservoir and allows hydraulic oil to communicate.

2. A work vehicle as described in claim 1, wherein the connecting oil passage connects the upper part of the first storage section and the lower part of the second storage section.

3. A work vehicle as described in claim 2, wherein the second storage section has a wall member that divides the interior of the second storage section into an upper area and a lower area, and a communication passage that connects the upper area and the lower area, and the connecting oil passage is connected to the lower area.

4. A work vehicle as described in claim 3, wherein the communication passage is provided near one of two sets of wall portions that face each other in the second storage section, and the portion of the connecting oil passage that is connected to the lower region is provided near the other of the two sets of wall portions that face each other in the second storage section.

5. A work vehicle as set forth in any one of claims 1 to 4, wherein the second reservoir is provided with an oil supply section capable of replenishing hydraulic oil.

6. A work vehicle as described in any one of claims 1 to 5, provided with a first oil supply passage that supplies hydraulic oil from the first reservoir to some of the plurality of work devices, and a second oil supply passage that supplies hydraulic oil from the second reservoir to some of the plurality of work devices.

7. A work vehicle as described in claim 6, wherein the second storage section has a wall member that divides the interior of the second storage section into an upper area and a lower area, and a communication passage that connects the upper area and the lower area, and the second supply oil passage is connected to the upper area.

8. A work vehicle as described in any one of claims 1 to 7, provided with: a first return oil passage that returns hydraulic oil from some of the plurality of work devices to the first reservoir; and a second return oil passage that returns hydraulic oil from some of the plurality of work devices to the second reservoir.

9. A work vehicle as claimed in any one of claims 1 to 8, comprising: a first supply oil passage that supplies hydraulic oil in the first reservoir to some of the working devices among the plurality of working devices; a second supply oil passage that supplies hydraulic oil in the second reservoir to some of the working devices among the plurality of working devices; a first return oil passage that returns hydraulic oil from some of the working devices among the plurality of working devices to the first reservoir; and a second return oil passage that returns hydraulic oil from some of the working devices among the plurality of working devices to the second reservoir, wherein the working devices include the working devices to which hydraulic oil is supplied from the first supply oil passage and which discharge the hydraulic oil into the first return oil passage, and the working devices to which hydraulic oil is supplied from the second supply oil passage and which discharge the hydraulic oil into the second return oil passage.

10. A work vehicle as described in claim 9, wherein the first storage section has a partition member that separates the interior of the first storage section into a first area and a second area, and a strainer through which hydraulic oil from the second area can pass and enter the first area, the first supply oil passage is connected to the first area, and the connecting oil passage and the first return oil passage are connected to the second area.

11. A work vehicle as described in claim 10, wherein the first area is provided at the upper part of the interior of the first storage section, and the strainer is connected to the lower part of the first area and extends downward from the lower part of the first area.

12. A work vehicle as described in claim 10 or 11, wherein the first area is provided at one side in the left-right direction or one side in the front-to-rear direction at the top of the interior of the first storage section, and the connecting oil passage is connected to a portion of the second area adjacent to the first area.

13. A work vehicle as set forth in any one of claims 9 to 12, including a work device that receives hydraulic oil from the first supply oil passage and outputs the hydraulic oil to the second return oil passage.

14. A work vehicle as set forth in any one of claims 9 to 13, including a work device that receives hydraulic oil from the second supply oil passage and outputs hydraulic oil to the first return oil passage.

15. A work vehicle as described in any one of claims 8 to 14, wherein the second storage section has a wall member that separates the interior of the second storage section into an upper area and a lower area, a communication passage that connects the upper area and the lower area, and includes the second return oil passage that is connected to the lower area.

16. A work vehicle as described in claim 15, wherein upper and lower pipe members are provided between the upper part of the second storage section and the lower part, passing through the upper part, and the second return oil passage connected to the lower part is connected to the upper and lower pipe members.

17. A work vehicle as described in claim 15 or 16, wherein the communicating passage is provided near one of two sets of wall portions that face each other in the second storage section, a horizontal pipe member is provided that extends from one of the two sets of wall portions that face each other in the second storage section across the communicating passage to the lower region, and the second return oil passage connected to the lower region is connected to the horizontal pipe member.

18. A work vehicle as described in any one of claims 8 to 17, wherein the second storage section has a wall member that separates the interior of the second storage section into an upper region and a lower region, and a communication passage that connects the upper region and the lower region, and includes the second return oil passage that is connected to the upper region, and is provided with a filter that allows the hydraulic oil in the second return oil passage that is connected to the upper region to pass through and be returned to the upper region.

19. A work vehicle according to any one of claims 1 to 18, wherein a hydrostatic continuously variable transmission that drives the traveling device is included in the work device.

20. A work vehicle as set forth in any one of claims 1 to 19, wherein the work device includes a transport device for transporting and discharging the material to be processed to the outside.

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