JP2009184612A - Hydraulic power unit of utility vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To alleviate the burden of work at the time of maintenance of a filter included in a hydraulic power unit for a utility vehicle, the filter intervening in the halfway of an oil path from a switching valve to a hydraulic instrument, and inhibiting foreign matters in the oil under pressure from entering the hydraulic instrument. <P>SOLUTION: A sub-block 43 is prepared which forms oil passages 47, 49, 53 therein constituting at least a part of the hydraulic oil path from the switching valve 34 to the hydraulic instrument 22, whereas the sub-block 43 is removably mounted and fixed on a main-block 36 to set the upper surface of the sub-block 43 in close contact with the undersurface of the main-block 36. The oil under pressure within the main-block 36 flows into the oil passage 47 in the sub-block 43 via the filter 35, by allocating the filter in between the main-block 36 and the sub-block 43, or in the vicinity of the surface of the sub-block 43 mated with the surface of the main-block 36. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hydraulic device for a work vehicle.

  The main block is equipped with a switching valve that controls the supply of pressure oil to the hydraulic equipment and prevents foreign matter in the pressure oil from entering the hydraulic equipment along the pressure oil path from the switching valve to the hydraulic equipment. Conventionally, a hydraulic device for a work vehicle shown in Patent Document 1 in which a filter is interposed is known. In addition, there are hydraulic devices for work vehicles shown in FIGS. 10 and 11 as substantially the same configuration as the hydraulic device for work vehicles having the above-described configuration.

In the hydraulic apparatus for a work vehicle shown in FIGS. 10 and 11, an installation space 83 for installing the filter 82 is formed in the main block 81, and the pressure oil from the switching valve 84 flows into the installation space 83. After that, it is configured to pass through the filter 82 in the installation space 83 and be supplied to the hydraulic clutch 86 which is a hydraulic device. The installation space 83 is opened to the outside of the main block 81 by an outlet 83a, and the outlet 83a is closed by a plug 87 to keep a sealed state in the installation space 83. The maintenance of the filter 82 is performed by removing the plug 87 from the outlet 83 a and taking out the filter 82 from the installation space 83.
Japanese Patent No. 3320223

  However, the hydraulic device for a work vehicle shown in FIGS. 10 and 11 inserts the plug 87 into the installation space 83 from the outlet 83a so that the filter 82 is pushed into the back side of the installation space 83 at the tip end side of the plug 87. Since the outlet 83a is blocked, there is a problem that even if the plug 87 is removed from the outlet 83a, there is a problem that it is difficult to remove the filter 82 on the back side of the installation space 83, and the filter 82 is caught on the back side of the installation space 83 In this case, the filter 82 becomes more difficult to take out and a problem remains. This problem is common to the hydraulic devices for work vehicles described in the above-mentioned patent documents.

  In addition to the above problems, in the hydraulic apparatus for a work vehicle in FIG. 10, the filter 82 is fixed to the inner peripheral surface side of the poppet 88 that reciprocates in the axial direction in the installation space 83. Has a problem that foreign matter in the pressure oil adhering to the filter 82 may be finely decomposed and pass through the filter 82 by reciprocating.

On the other hand, in the hydraulic device for a work vehicle in FIG. 11, the plug 87 is formed of a sealing bolt, and the oil passage 87a that forms part of the pressure oil path from the switching valve 84 to the hydraulic equipment and extends coaxially with the sealing bolt is described above. It is formed in the sealing bolt 87, and a poppet 88 is provided in this oil passage 87a. As a result, the overall length (axial length) of the sealing bolt 87 is increased, and the filter 82 is pushed deeper into the installation space 83, so that it is more difficult to remove the filter 82 from the installation space 83. There is a problem of becoming.
The present invention solves the above problems, and in a hydraulic device for a work vehicle that includes a filter that prevents foreign matter in the pressure oil from entering the hydraulic device in the middle of the pressure oil path from the switching valve to the hydraulic device, The object is to reduce the work burden when maintaining the filter.

  In order to solve the above-described problems, the hydraulic device for a work vehicle according to the present invention includes a main block 36 in which a switching valve 34 for controlling the supply of pressure oil to the hydraulic device 22 is provided. In a hydraulic apparatus for a work vehicle in which a filter 35 for preventing foreign matter in the hydraulic oil from entering the hydraulic equipment 22 is interposed in the middle of the hydraulic oil path, the hydraulic path from the switching valve 34 to the hydraulic equipment 22 is changed. A sub-block 43 having at least a part of oil passages 47, 49, 53 is provided, and the sub-block 43 can be attached to and detached from the main block 36 so that the upper surface of the sub-block 43 is in close contact with the lower surface of the main block 36. The filter 35 is disposed between the main block 36 and the sub block 43 or in the vicinity of the mating surface of the sub block 43 with the main block 36. The Rukoto is characterized in that the pressure oil in the main block 36 flows into the oil passage 47,49,53 subblock 43 through the filter 35.

  According to the hydraulic device for a work vehicle of the present invention configured as described above, the filter is disposed between the main block and the sub block or in the vicinity of the mating surface with the main block of the sub block. By removing from the main block, it is possible for the operator to easily access the filter, and there is an effect that the work burden when maintaining the filter is reduced.

  FIG. 1 is a perspective view of a tractor to which the present invention is applied. This tractor mainly includes a traveling machine body 3 having front and rear wheels 1 and 2 and a working machine (not shown) such as a rotary tiller that is connected to the rear of the traveling machine body 3 so as to be movable up and down. The traveling machine body 3 is driven forward and backward by an operator seated in a driver's seat (not shown) in the standing cabin 4 so as to perform tilling work and the like on the field.

  2 is a power transmission system diagram of the tractor, FIG. 3 is a side view of the mission case, and FIG. 4 is a plan view of the mission case. The tractor is configured such that the power of the engine 6 is transmitted to the front and rear wheels 1 and 2 through the transmission 7. The transmission 7 is covered and protected by a transmission case 8. The transmission case 8 includes a front case 8a, an intermediate case 8b behind the front case 8a, and a rear case 8c behind the intermediate case 8b.

  The transmission 7 includes a main clutch 9 that turns on and off the power transmission from the engine 8 to the transmission shaft S1, a main transmission unit 11 that shifts power from the transmission shaft S1 to the transmission shaft S3 in four stages, and a transmission shaft. A forward / reverse switching unit 12 that transmits power from S3 to the transmission shaft S4 by forward rotation or reverse rotation, a sub-transmission unit 13 that shifts power from the transmission shaft S4 to the transmission shaft S5 in two stages, and a transmission shaft S5 And a front wheel transmission portion 14 that transmits the power from the front wheel 1 to the front wheel 1, and the power of the transmission shaft S 5 is transmitted to the left and right rear wheels 2.

  The main transmission unit 11 is always meshed with the four input gears 16a, 16b, 16c, and 16d that rotate integrally with the transmission shaft S1, and the two input gears 16a and 16d that are rotatably supported by the transmission shaft S2 and corresponding to each other. The output gears 17a and 17d, the output gears 17b and 17c that are rotatably engaged with the transmission shaft S3 and always meshed with the corresponding two input gears 16b and 16c, and any of the two output gears 17a and 17d. The switching transmission mechanism 18 that transmits one of the powers to the transmission shaft S2, the switching transmission mechanism 19 that transmits one of the two output gears 17b and 17c to the transmission shaft S3, and the power of the transmission shaft S2. And a transmission mechanism (not shown) that transmits to the transmission shaft S3.

  The switching transmission mechanisms 18, 19, 23, and 24 described above or later have two hydraulic clutches, and by supplying pressure oil to one of the two hydraulic clutches, the power on one side of the two output gears is increased. In addition to being transmitted to the transmission shaft, by supplying pressure oil to the other of the two hydraulic clutches, the power on the other side of the two output gears is transmitted to the transmission shaft. As a result, the power of the two output gears is not transmitted to the transmission shaft.

  Of the two hydraulic clutches 22 and 22 of the switching transmission mechanism 18, one of the two hydraulic clutches 22 and 22 transmits the power of the output gear 17a to the transmission shaft S2 so that the main transmission unit 11 is in the first speed switching state. (Refer to FIG. 5), and the other is the fourth speed switching clutch 22D (refer to FIG. 5) which transmits the power of the output gear 17d to the transmission shaft S2 to bring the main transmission 11 into the fourth speed switching state. One of the two hydraulic clutches 22 and 22 of the switching transmission mechanism 19 transmits the power of the output gear 17b to the transmission shaft S3, and the second speed switching clutch 22B (see FIG. 5), and the other is the third speed switching clutch 22C (see FIG. 5) that transmits the power of the output gear 17c to the transmission shaft S3 to bring the main transmission 11 into the third speed switching state.

  The forward / reverse switching unit 12 includes a switching transmission mechanism 23 having two hydraulic clutches 26, 26, and supplies pressure oil to a forward switching clutch 26A (see FIG. 5) which is one hydraulic clutch 26 of the switching transmission mechanism 23. As a result, power in the normal rotation direction is transmitted to the transmission shaft S4 to drive the machine forward, and pressure oil is supplied to the reverse switching clutch 26B (see FIG. 5), which is the other hydraulic clutch 26, to the transmission shaft S4. The power in the reverse direction is transmitted to drive the aircraft backward.

  The auxiliary transmission unit 13 includes a switching transmission mechanism 24 having two hydraulic clutches 28, 28, and supplies pressure oil to a low-speed switching clutch 28 </ b> A (see FIG. 5) that is one hydraulic clutch 28 of the switching transmission mechanism 24. Thus, the power is transmitted to the transmission shaft S5 at a low speed, and the power is transmitted to the transmission shaft S5 at a high speed by supplying pressure oil to the high-speed switching clutch 28B (see FIG. 5) which is the other hydraulic clutch 28. ing.

  The front wheel transmission unit 14 is configured to turn on / off power transmission from the engine 6 to the front wheel 1.

Next, the configuration of the hydraulic device will be described with reference to FIGS.
FIG. 5 is a hydraulic circuit diagram of a hydraulic apparatus to which the present invention is applied. The lubricating oil in the mission case 8 is also used as hydraulic oil for operating the various hydraulic devices described above. The pressure oil in the mission case 8 is provided on the left side of the engine 6 in front of the mission case 8 via a suction filter 31 and a hydraulic pipe P1 installed on the rear side of the left side of the mission case 8, and is driven by the engine 6. The hydraulic pumps 32 and 33 are supplied, and the two hydraulic pumps 32 and 33 are pumped to various hydraulic devices.

  The pressure oil from the hydraulic pump 32 is supplied with four electromagnetic switching valves 34 (switching valves) for controlling the supply of pressure oil to the four hydraulic clutches 22 (hydraulic equipment) of the main transmission unit 11 via the hydraulic pipe P2. ) Is installed in the main transmission block 36 (main block) in which it is installed. The main transmission block 36 is fixed on the upper surface of the front case 8a.

  The electromagnetic switching valve 34 that controls the supply of pressure oil to the first speed switching clutch 22A becomes the first speed switching valve 34A, and the electromagnetic switching valve 34 that controls the supply of pressure oil to the second speed switching clutch 22B. Becomes the second speed switching valve 34B, the electromagnetic switching valve 34 for controlling the supply of the pressure oil to the third speed switching clutch 22C becomes the third speed switching valve 34C, and the pressure oil to the fourth speed switching clutch 22D The electromagnetic switching valve 34 for controlling the supply becomes the fourth speed switching valve 34D.

  Each of the four electromagnetic switching valves 34 discharges pressure oil from the control target hydraulic clutch 22 into the transmission case 8 in a supply mode for forming a flow path for supplying pressure oil to the control target hydraulic clutch 22. And a discharge mode for forming a flow path. The four electromagnetic switching valves 34 are controlled such that when one of them is in the supply mode, the other three are in the discharge mode, and any one of the powers of the four output gears 17a, 17b, 17c, 17d is transmitted to the transmission shaft S3. It is transmitted to.

  In addition, a filter 35 (line filter) and a poppet 37 are provided in the middle of the pressure oil path between each electromagnetic switching valve 34 and each corresponding hydraulic clutch 22.

  The poppet 37 functions as a one-way throttle valve, and when supplying pressure oil to the corresponding hydraulic clutch 22, slowly supplies the pressure oil to the hydraulic clutch 22 via a throttle passage 37 a described later, and the corresponding hydraulic clutch At the time of discharging the pressure oil from the pressure oil 22, the pressure oil is quickly discharged from the hydraulic clutch 22 via a sub-flow passage 37 b described later. Due to the above-described action of the poppet 37, it is possible to prevent malfunction of other hydraulic equipment due to the rapid supply of pressure oil into the hydraulic clutch 22 and the pressure oil of the hydraulic oil rapidly decreasing.

  The filter 35 is arranged on the upstream side of the poppet 37 in the pressure oil path from the electric switching valve 34 to the hydraulic clutch 22, and foreign matter in the pressure oil supplied from the electric switching valve 34 enters the throttle channel of the poppet 37. Clogging and entry into the hydraulic clutch 22 are prevented.

  The pressure oil in the main transmission block 36 is supplied via a hydraulic pipe P3 to a sub transmission switching valve 38 (electromagnetic switching valve) that controls the supply of pressure oil to the two hydraulic clutches 28 (hydraulic equipment) of the sub transmission 13. ) Is supplied into the installed sub-shift block 39. The auxiliary transmission block 39 is disposed on the right side surface of the intermediate case 8b.

  The sub-transmission switching valve 38 supplies the pressure oil from the hydraulic pipe P3 to the low-speed switching clutch 28A, and forms a flow path for discharging the pressure oil from the high-speed switching clutch 28B into the transmission case 8, and the hydraulic pipe. A high-speed mode is provided that forms a flow path for supplying the pressure oil from P3 to the high-speed switching clutch 28B and discharging the pressure oil from the low-speed switching clutch 28A into the mission case 8.

  The pressure oil in the auxiliary transmission block 39 is moved forward and backward by a forward / reverse switching valve 41 (electromagnetic switching) that controls the supply of pressure oil to the two hydraulic clutches 26 (hydraulic equipment) of the forward / reverse switching section 12 via a hydraulic pipe P4. Is supplied into the forward / reverse block 42 where the valve is installed. The forward / reverse block 42 is fixed to the left side surface of the intermediate case 8b.

  The forward / reverse switching valve 41 includes a forward mode for forming a flow path for supplying the pressure oil from the hydraulic pipe P4 to the forward switching clutch 26A and discharging the pressure oil from the reverse switching clutch 26B into the transmission case 8, and the hydraulic pipe. A reverse mode in which pressure oil from P4 is supplied to the reverse switching clutch 26B and a flow path for discharging the pressure oil from the forward switching clutch 26A into the mission case 8 is formed, and from the forward switching clutch 26A and the reverse switching clutch 26B And a stop mode in which the pressure oil is discharged into the mission case 8.

  The forward / reverse switching valve 41 is mechanically connected to a switching lever that is supported in the driver's seat so as to be able to swing back and forth. The operator operates the switching lever back and forth to move forward and backward. Switch between mode and stop mode.

Next, a pressure oil path from the electromagnetic switching valve to the hydraulic clutch will be described in detail with reference to FIGS.
FIG. 6 is a plan view of main parts of a main block and a sub block showing a pressure oil path from the electromagnetic switching valve to the hydraulic clutch, and FIG. 7 is a main block showing a pressure oil path from the electromagnetic switching valve to the hydraulic clutch. FIG. 8 is a main part front view of the main block and the sub block showing a pressure oil path from the first speed switching valve to the first speed switching clutch. FIG. It is a principal part side view of the main block which shows the pressure oil path | route from a 2nd speed switching valve to a 2nd speed switching clutch.

  The main block 36 is formed in a rectangular parallelepiped shape that is long in the left-right direction. The above-described four electromagnetic switching valves 34 are inserted and supported in the front-rear direction from the rear surface (after the traveling direction) to the inside. The four electromagnetic switching valves 34 are arranged in parallel evenly over the entire left and right direction of the main block 36 and are detachably bolted to the main block 36.

  In the left half of the main block 36, two electromagnetic switching valves 34 are arranged in order of the first speed switching valve 34A and the second speed switching valve 34B from the left side to the right side. Below these two electromagnetic switching valves 34A, 34B are oil passages 47, 49, 53 that constitute part of the pressure oil path from the electromagnetic switching valves 34A, 34B to the corresponding hydraulic clutches 22A, 22B. The formed rectangular parallelepiped left sub-block 43 (sub-block) is provided.

  The sub block 43 is disposed in a space between the lower surface of the rear end of the main block 36 and the upper surface of the front case 8a. Then, the sub block 43 is pressed against the main block 36 so that the upper surface (mating surface) of the sub block 43 is pressed to the lower surface (mating surface) of the main block 36 without a gap by a bolt (not shown). It is detachably attached and fixed.

  On the other hand, in the right half of the main block 36, two electromagnetic switching valves 34 are arranged in the order of the third speed switching valve 34C and the fourth speed switching valve 34D from the left side to the right side. Below the two electromagnetic switching valves 34C and 34D, a right sub-block (sub block) (not shown) having a rectangular parallelepiped shape in which oil passages from the electromagnetic switching valves 34C and 34D to the corresponding hydraulic clutches 22C and 22D are formed. ) Is provided.

  The right half of the main block 36 is configured to be substantially the same as the left half of the main block 36 and the right sub block is configured substantially the same as the left sub block 43. Therefore, the configuration of the left half of the main block 36 and the left sub block 43 will be described below. Only will be described.

  In the supply mode, the pressure oil from the electromagnetic switching valve 34 is supplied to the oil passage 44 in the front-rear direction formed in the lower part of the main block 36 so that the pressure oil in the oil passage 44 is substantially circular in cross section. It flows vertically into the main block side space 46 (installation oil passage, oil passage) that is formed in the vertical direction and is open at the bottom and accessible from the lower surface side of the main block.

  With respect to the main block side space 46, the sub block 43 has a sub block side space 47 (for installation) that extends in the vertical direction so as to be substantially circular in cross section and is open upward and accessible from the upper surface side of the sub block 43. Oil passage, oil passage) is formed. A stepped portion is formed in the open end portion of the sub-block side space 47 so that the diameter gradually decreases, and a tapered portion is formed in the middle portion so as to gradually decrease in the depth direction. The diameter in the range from the stepped portion to the tapered portion is substantially the same as the diameter of the main block side space 46.

  The main block side space 46 and the sub block side space 47 are attached and fixed to the main block 36 to form a single installation space in which the filter 35 and the poppet 37 are installed. Is configured to do.

  The filter 35 includes a cylindrical portion having a diameter larger than that of the main block side space 46, and a net-like portion having a dome-like rise on the main block 36 side so as to close the main block side open end of the cylindrical portion. It is configured. Since this mesh portion has a function of filtering foreign matter in the pressure oil, the pressure oil in the main block 36 is filtered by the filter 35 and supplied (inflow) into the sub-block 43 in the supply mode.

  Then, the tubular portion of the filter 35 is fitted into the stepped portion of the sub-block side space 47 with the O-ring 48 mounted on the tubular upper portion of the filter 35, and the sub-block 43 is attached and fixed to the main block 36. Thus, the filter 35 is pressed by the lower surface of the main block 36 and fitted and fixed in the main block side space 46, and the O-ring 48 is pressed against the stepped portions of the lower surface of the main block and the sub block side space 47, The installation space for the poppet 37 is sealed.

In the example shown in the figure, since the mesh portion of the filter 35 is raised toward the main block 36, the filter 35 is disposed between the blocks 36 and 43 extending from the main block 36 to the sub-block 43. The shape of the net-like portion and the shape of the stepped portion of the sub-block side space 47 may be changed so that 35 is arranged in the vicinity of the mating surface of the main block 36 and the sub-block 43 in the sub-block 43.

  The poppet 37 is a hollow member extending in the axial direction of the sub-block side space 47, and is inserted and supported so as to be movable in the axial direction in the sub-block side space 47 in which the filter 35 is fitted and fixed. In the poppet 37, an end portion (tip portion) far from the open end of the sub-block side space 47 is provided with a throttle channel 37a having a small channel diameter communicating with the inside and outside of the poppet, and the tip of the poppet 37 Sub-channels 37b that allow the inside and outside of the poppet to communicate with each other are formed at four locations on the outer periphery of the part, while the base end portion of the poppet 37 is opened so that the inside and outside communicate.

  In the supply mode, the pressure oil from the electromagnetic switching valve 34 flows into the inside from the base end opening side of the poppet 37 to press the poppet 37 toward the back side of the sub block side space 47, and the outer periphery of the tip end portion of the poppet 37 is the sub block. The abutment is in close contact with the tapered portion of the side space 47, but the sub-path 37b of the poppet 37 is located on the proximal side from the abutting position of the poppet 37 on the tapered portion of the sub-block side space 47. The pressure oil in the poppet 37 is not supplied from the sub-channel 37b to the back side of the sub block side space 47, but flows out from the throttle channel 37a to the back side end of the sub block side space 47.

  On the other hand, in the discharge mode, the pressure oil from the hydraulic clutch 22 presses the poppet 37 toward the open end side of the sub-block side space 43, so that the outer periphery of the tip of the poppet 37 is separated from the tapered portion of the sub-block side space 37. The contact between the two is released, and the pressure oil at the back end of the sub-block side space 47 passes through the throttle channel 37a, the four sub-channels 37b, etc., and reaches the open end side of the sub-block side space 47. Returned to the valve 34 side.

  In the supply mode, the pressure oil on the open end side of the sub-block side space 47 is supplied to a pressure detection oil passage 49 (oil passage) formed in the lower part of the sub-block 43 and extending in the horizontal direction. The pressure detection oil passage 49 communicates with the outside of the sub block 43 through an opening 51 formed on the outer surface of the sub block 43 and opened in the horizontal direction. By providing a pressure detector (not shown) or the like in the opening 51, the pressure in the pressure oil path from the electromagnetic switching valve 34 to the hydraulic clutch 22 can be checked. For this reason, this opening part 51 becomes a pressure detection port of a hydraulic device. The opening 51 is normally closed by a sealing plug 52 and the sealed state in the pressure detection oil passage 49 is maintained.

  The pressure oil in the pressure detection oil passage 49 is generated in the main block 36 by a vertical oil passage 53 formed in a range extending from the sub block 43 to the main block 36 when the bolt of the sub block 43 to the main block 36 is fixed. Then, the oil pressure is supplied to the hydraulic clutch 22 through the oil passage 54 in the main block 36.

  Incidentally, a plurality of oil passages 44, 46, 47, 49, 53, 54 constituting a pressure oil passage from the electromagnetic switching valve 34 to the corresponding hydraulic clutch 22 are provided for each electromagnetic switching valve 34 and communicate with each other. Not.

  The plurality of oil passages 44, 46, 47, 49, 53, and 54 constituting the pressure oil passage from the first speed switching valve 34A to the first speed switching clutch 22A are the first speed switching oil passages 44A and 46A. 47A, 49A, 53A, 54A, and the plurality of oil passages 44, 46, 47, 49, 53, 54 constituting the pressure oil passage from the second speed switching valve 34B to the second speed switching clutch 22B are The second speed switching oil passages 44B, 46B, 47B, 49B, 53B, and 54B are obtained.

It is a perspective view of a tractor to which the present invention is applied. It is a power transmission system diagram of this tractor. It is a side view of a mission case. It is a top view of a mission case. 1 is a hydraulic circuit diagram of a hydraulic apparatus to which the present invention is applied. It is a principal part top view of the main block and subblock which show the pressure oil path | route from an electromagnetic switching valve to a hydraulic clutch. It is a principal part front view of the main block and subblock which show the pressure oil path | route from an electromagnetic switching valve to a hydraulic clutch. It is a principal block side view of a main block and a sub block which shows a pressure oil course from the 1st speed change valve to the 1st speed change clutch. It is a principal part side view of the main block which shows the pressure oil path | route from a 2nd speed switching valve to a 2nd speed switching clutch. It is sectional drawing which shows an example of the hydraulic device of the conventional work vehicle. It is sectional drawing which shows an example of the hydraulic device of the conventional work vehicle.

Explanation of symbols

22 Hydraulic clutch (hydraulic equipment)
34 Electromagnetic switching valve (switching valve)
35 Filter (Line filter)
36 Main transmission block (main block)
43 Sub-block 47 Sub-block side space (Installation oil passage, oil passage)
49 Pressure detection oil passage (oil passage)
53 Oilway

Claims (1)

  A main block (36) provided with a switching valve (34) for controlling the supply of pressure oil to the hydraulic equipment (22) is provided, and in the middle of the pressure oil path from the switching valve (36) to the hydraulic equipment (22). In a hydraulic device for a work vehicle that includes a filter (35) that prevents foreign matter in the pressure oil from entering the hydraulic device (22), the hydraulic pressure from the switching valve (34) to the hydraulic device (22) is increased. A sub-block (43) in which oil passages (47), (49), (53) constituting at least a part of the path are formed is provided, and the upper surface of the sub-block (43) is placed on the lower surface of the main block (36). The sub block (43) is detachably attached and fixed to the main block (36) so as to be in close contact, and the filter (35) is placed between the main block (36) and the sub block (43) or the sub block (43). Maine By disposing in the vicinity of the mating surface with the lock (36), the pressure oil in the main block (36) passes through the filter (35) and the oil passages (47), (49), ( 53) The hydraulic device of the work vehicle that flows into the vehicle.

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