JP6803263B2 - Work vehicle - Google Patents

Description

The present invention relates to a work vehicle in which a hydraulic clutch type gear transmission is installed in a transmission case.

Agricultural tractors as work vehicles travel by transmitting the power of the engine to the front and rear wheels via the transmission and differential that are built into the transmission case, and the PTO transmission that is also built into the transmission case. Through, for example, a working machine connected to the rear part of the tractor is driven.

Further, these transmissions built in the transmission case are gear transmissions of a constant mesh type, for example, in a state where the main clutch built in the clutch housing case is disengaged by depressing the clutch pedal. A mechanical gear transmission that manually switches the gears by sliding the shift fork, a hydraulic clutch type gear transmission that changes the meshing state of the gears by selectively joining the hydraulic clutch, and the like are adopted.

In the latter hydraulic clutch type, shifting can be performed (without clutch) without depressing the clutch pedal to disengage the main clutch, and shifting operation can be performed smoothly. However, since this type is provided with a hydraulic clutch, a hydraulic control circuit, etc., it is generally more expensive than the former mechanical type.

Then, it is necessary to prepare two or more types of tractors so that one of a specification that adopts a mechanical gear transmission and a specification that adopts a hydraulic clutch type gear transmission can be selected according to the user's preference. Even if the specifications are different, it is known that if the transmission cases can be used in combination with each other, the cost will be significantly reduced compared to the case where the transmission cases are manufactured separately using a new mold (). See Patent Document 1).

On the other hand, when the above-mentioned hydraulic clutch type gear transmission is configured, it is necessary to supply the hydraulic oil pressure-fed from the hydraulic pump to the hydraulic clutch built in the transmission case via the hydraulic control valve and the oil passage. In this case, if the distance from the hydraulic control valve to the hydraulic clutch is large, an oil passage connecting the two is provided on the outer surface of the transmission case by using an external pipe or a hydraulic hose.

Further, for the purpose of shortening the pipe length of the oil passage and arranging the hydraulic control valves of a plurality of hydraulic clutch type transmissions in an integrated manner, a plurality of hydraulic control valves are provided in a single valve block. The valve block is attached to the outer surface of the side wall of the transmission case in which the hydraulic clutch type transmission is installed, and the hydraulic clutch is made by using a plurality of conduit members or pipes through which the side wall is passed and a hydraulic oil passage of the bearing frame provided in the side wall. It is known to form an oil passage for supplying hydraulic oil (see Patent Document 2).

Further, in the second embodiment of this, the hydraulic clutch provided in the second bearing frame separated from the first bearing frame by a plurality of pipes spanning the first and second bearing frames. It is exemplified that the hydraulic oil is supplied, that is, the oil passage of the hydraulic oil is performed in the transmission case by its internal pipe (pipe).

Japanese Unexamined Patent Publication No. 2001-105911 Japanese Unexamined Patent Publication No. 11-291777

As mentioned above, in a work vehicle in which a hydraulic clutch type gear transmission is installed in the transmission case, it is effective to use the transmission case that mainly employs a mechanical gear transmission, etc. in combination to reduce costs. is there. In addition, when the transmission case is also used, the basic transmission form of the transmission is not changed, for example, only the part related to the gear transmission to be changed to the hydraulic clutch type is changed, and most of the remaining transmissions are followed as they are. For example, a transmission that has already been verified can be used to configure a highly reliable transmission.

Therefore, when trying to change only the gear transmission, which was previously composed of a mechanical type, to a hydraulic clutch type without significantly changing its transmission form, the mechanical gear transmission was switched by sliding the shift fork. The device will be changed to a form in which the hydraulic clutch is engaged and disengaged by supplying and discharging hydraulic oil. That is, the hydraulic oil pumped from the hydraulic pump must be supplied to the hydraulic clutch built in the transmission case via the hydraulic control valve and the oil passage.

Therefore, it is conceivable to use a pipe or a hydraulic hose on the outer surface of the side wall of the transmission case to provide an oil passage for supplying hydraulic oil from the hydraulic control valve to the hydraulic clutch built in the transmission case as in the conventional case. However, on the left and right outside of the transmission case, there are arrangements such as a transmission lever connecting mechanism that operates the shift fork that operates the mechanical gear transmission, piping to other flood control equipment, and electrical harnesses. Therefore, if a new hydraulic pipe or hydraulic hose is provided at such a location, there is a concern about the strength of the pipe and the occurrence of problems due to contact with harnesses.

On the other hand, as described in Prior Art Document 2, when a valve block provided with a hydraulic control valve is attached to the outer surface of the side wall of a transmission case in which a hydraulic clutch type transmission is installed, between the hydraulic control valve and the hydraulic clutch. Although the length of the oil passage can be shortened, the hydraulic pipes and hydraulic hoses from the hydraulic pump to the valve block will still be provided on the outer surface of the side wall of the transmission case, and the fuel tanks will be installed on the left and right outside of the transmission case. If this is provided, there is a downside that maintenance of the flood control valve and the like cannot be performed unless this fuel tank is removed.

Therefore, it is required to surely guide the hydraulic oil to the hydraulic clutch without providing a new pipe, a hydraulic hose, a hydraulic control valve, or the like on the outer surface of the side wall of the transmission case. One hint is that the hydraulic oil hose illustrated in the second embodiment is provided in the transmission case by its internal piping.

However, when the hydraulic oil passage is performed in the transmission case by its internal piping, the oil passage is formed by a plurality of pipes spanning between the first and second bearing frames as in Prior Art Document 2. As a result, a plurality of pipes are required and the number of parts is increased, and a man-hour is required to accurately incorporate the plurality of pipes between the first and second bearing frames, and there is room for improvement in the internal piping structure thereof.

Therefore, in view of the above-mentioned problems, the present invention does not significantly change the transmission form of the transmission in the transmission case when the transmission is changed from the mechanical type to the hydraulic clutch type. Another problem is to provide a reliable work vehicle while reducing the cost by using the internal oil passage to supply the hydraulic oil and lubricating oil pumped from the hydraulic pump to the hydraulic clutch. And.

In order to solve the above problems, the present invention supplies hydraulic oil or lubricating oil pumped from a hydraulic pump to a hydraulic clutch built in a transmission case via a valve block provided with a hydraulic control valve and a plurality of oil passages. In a work vehicle for shifting a gear transmission by the hydraulic clutch, a first support wall of the transmission case, a transmission shaft for supporting the hydraulic clutch, a second support wall for supporting one end of the transmission shaft, and the above. When a plurality of oil supply holes are bored in each of the oil passage shafts erected over the first and second support walls and these oil supply holes are communicated with each other to form a plurality of oil passages, the oil is described. A plurality of oil feeding holes to be bored in the road shaft are composed of horizontal holes in the axial direction and vertical holes that communicate with the horizontal holes from the annular grooves formed near the left and right ends of the outer peripheral surface, and the left and right annular grooves. Is formed approximately the same dimension apart from each end face of the oil passage shaft, so that even if the oil passage shaft is erected on the first and second support walls in the opposite directions, the hydraulic oil is directed toward the hydraulic clutch. It is characterized in that it is configured so that the lubricating oil can be supplied without any trouble .

Further, in the present invention, a mounting hole for a plug larger than the inner diameter of the horizontal hole is provided at the end of the horizontal hole formed in the oil passage shaft, and the plug is mounted in the mounting hole to close the end, and the plug is used. The end that does not close is characterized in that a mounting hole is not provided so that the plug cannot be mounted and the plug is not erroneously mounted.

According to the work vehicle of the present invention, when hydraulic oil or lubricating oil pumped from a hydraulic pump is supplied to a hydraulic clutch built in a transmission case via a valve block having a hydraulic control valve and a plurality of oil passages, the transmission The first support wall of the case, the transmission shaft that supports the hydraulic clutch, the second support wall that supports one end of the transmission shaft, and the oil passage shaft erected over the first and second support walls. A plurality of oil supply holes are formed in each of the oil pump holes, and these oil supply holes are communicated with each other to form a plurality of oil passages.

Therefore, a valve block provided with a hydraulic control valve is provided at a position facing the first support wall of the transmission case, and one end of a transmission shaft provided with a hydraulic clutch is provided on the second support wall away from the first support wall. Even if it is supported, the oil supply hole of the first support wall and the oil supply hole of the second support wall are communicated with each other through the oil supply hole of the oil passage shaft, and the oil pressure is separated from the valve block provided with the hydraulic control valve. It is possible to supply hydraulic oil and lubricating oil to the clutch.

Therefore, it is possible to increase the degree of freedom in the installation location of the hydraulic clutch type gear transmission as well as the installation location of the valve block provided with the hydraulic control valve. Therefore, only the gear transmission that has been mechanically configured until then is transmitted. The form can be changed to a hydraulic clutch type without drastically changing the form, so that the transmission case can be used in combination regardless of the difference in specifications, and the cost can be reduced.

Further, since the oil passages for hydraulic oil and lubricating oil can be provided in the transmission case by the internal oil passages, the hydraulic pressure can be applied without installing new pipes, hydraulic hoses, hydraulic control valves, etc. on the side walls of the transmission case. The hydraulic oil and lubricating oil can be reliably supplied to the clutch.

Further, since the oil passage shaft is provided with a plurality of oil feeding holes to supply hydraulic oil and lubricating oil to the hydraulic clutch, they are bridged between the first and second bearing frames (support walls) as in the conventional case. This oil passage shaft is supported by the first and second parts as a single-part oil passage shaft without the need for multiple pipes for hydraulic oil or lubricating oil, as in the case where an oil passage is composed of multiple pipes. Since it is only necessary to erection over the wall, the number of assembly steps can be reduced and the cost can be reduced.

A plurality of oil feeding holes to be bored in the oil passage shaft are composed of horizontal holes in the axial direction and vertical holes communicating with the horizontal holes from the annular groove formed near the left and right ends of the outer peripheral surface, and the left and right sides thereof. An annular groove is formed at a distance of substantially the same dimension from each end surface of the oil passage shaft, so that even if the oil passage shaft is erected on the first and second support walls in the opposite directions, the oil passage shaft is directed toward the hydraulic clutch. If the hydraulic oil and the lubricating oil can be supplied without any trouble, it is not necessary to consider the direction of the oil passage shaft when erection of the oil passage shaft over the first and second support walls. Assemblability can be improved.

In addition, a plug mounting hole larger than the inner diameter of the horizontal hole is provided at the end of the lateral hole drilled in the oil passage shaft, and the plug is attached to this mounting hole to close the end, and the end not closed by the plug is attached. If the plug is not provided with a hole and the plug cannot be attached to prevent the plug from being erroneously attached, an oil sump is provided at the innermost part of the attachment hole of the oil passage shaft provided on the first and second support walls. The oil sump and the horizontal hole of the oil passage shaft can be communicated with each other and used as one oil passage. In this case, it is possible to easily prevent erroneous mounting of the plug depending on the presence or absence of a plug mounting hole larger than the inner diameter of the horizontal hole provided at the end of the horizontal hole.

It is a side view of a tractor. It is a perspective view seen from the bottom surface side of a tractor. It is a development view of a transmission. It is a development view of the forward / backward switching device. It is a hydraulic circuit diagram. It is sectional drawing which shows the transmission which is built in the clutch housing case. It is a perspective view of the intermediate support plate (second support wall). An intermediate support plate (second support wall) is shown, (a) is a plan view, (b) is a front view, and (c) is a side view. It is sectional drawing which shows the erection state of the oil passage shaft. It is a perspective view of the oil passage shaft. It is a schematic diagram which shows the communication method of the oil feed hole of an oil passage shaft.

Embodiments of the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, the tractor 1 as a work vehicle constitutes a vehicle body (airframe) by integrally connecting an engine 2, a clutch housing case 3, a center case 4, a differential case 5, and the like from the front. Further, on the front side of the vehicle body, a bonnet 8 having a headlight 6 and a grill 7 on the front surface to cover auxiliary equipment such as an engine 2 and a battery, and left and right side covers 9 below the bonnet 8 are provided.

Further, the front axle case 11 is pivotally supported on the front bracket 10 which is fixed to the engine 2 and extends forward. Front axle cases (kingpin case and final case) 12 are attached to the left and right ends of the front axle case 11. Further, the front axle case 12 pivotally supports the front axle 14 to which the front wheels 13 are attached, and the left and right front wheels 13 are steered via the power steering unit A by the steering wheel 15 provided in the steering unit.

On the other hand, a rear axle case (not shown) connected to the left and right of the differential case 5 is provided on the rear side of the vehicle body, and the left and right rear wheels 17 are attached to the rear axle 16 pivotally supported by the rear axle case. Further, a well-known three-point link mechanism including a top link 18 and left and right lower links 19 is provided at the rear portion of the vehicle body.

This three-point link mechanism connects working machines such as a mower and a rotary tiller, and the working machines are the left and right lift arms 21 of the hydraulic housing 20 attached to the upper part of the differential case 5 and the left and right lift arms 21. It goes up and down via a lift rod (not shown) that connects one end to the middle of the tip and the left and right lower links 19. Further, the engine power is transmitted to the work machine from the PTO shaft (power take-out shaft) 22 that is pivotally supported at the rear portion of the differential case 5.

Further, the floor 23 is attached to the vehicle body behind the engine 2 via a vibration isolator. A steering wheel 15 is provided on the steering column near the front of the floor 23, and a meter panel 24 including an instrument panel and a rear panel cover 25 covering the lower side thereof are provided. Further, the driver's seat 26 is provided on the seat lower cover provided at the rear end of the floor 23, and the left and right fenders 27 covering the range from the front to the upper side of the rear wheel 17 are provided on the side of the driver's seat 26.

The rear side of the driver's seat 26 is composed of left and right lower columns (not shown) attached to the rear axle case via a vibration isolator, and an inverted U-shaped roll bar 28 attached to the upper part of the lower columns. Provide a safety frame. 29 is a sub-step that serves as a stepping stone when getting on and off from the floor 23, 30 is a fuel tank provided between the clutch housing case 3 and the sub-step 29 (not shown in FIG. 2), and 31 is the left and right fenders 27. It is an assist grip when getting on and off, which is provided near the upper part of the.

In addition, various operating tools are provided in the control unit around the driver's seat 26. That is, a forward / backward switching lever 32 is provided near the upper left portion of the rear panel cover 25, and an engine control lever 33 is provided on the right steering column. Further, a clutch pedal 34 is provided on the left side of the floor 23 near the front portion, and left and right brake pedals (not shown) are provided on the other side. Further, a side panel (not shown) is provided between the left and right fenders 27 and the driver's seat 26, and a hydraulic control lever for raising and lowering the work equipment, a PTO shift lever, and a main shift lever for changing the vehicle speed are provided on the side panel. Provide an auxiliary shift lever, etc.

Next, the transmission of the tractor 1 will be described. As shown in the development view of FIG. 3, the transmission drives a traveling system transmission device that transmits the power of the engine 2 to the rear axle 16 or the front axle 14 and a working machine. A PTO system transmission device that transmits to the PTO shaft 22 is provided, and these transmission devices are housed in a transmission case T composed of a clutch housing case 3, a center case 4, and a differential case 5 that are integrally connected to the rear portion of the engine 2. To do.

A fly wheel 35 connected to the output shaft of the engine 2 and a dry single plate clutch 36 constituting the main clutch are provided on the front side of the clutch housing case 3, and the dry single plate clutch 36 is a clutch pedal 34. The clutch lever 37 and the release hub 38 connected to the above interrupt and interrupt the power transmission to the first drive shaft 39 of the traveling system which is the outer shaft of the double shaft. The PTO drive shaft 40, which is the inner shaft, transmits the power of the engine 2 as it is via the flywheel 35.

Further, a main transmission 41 composed of a gear transmission that is always meshed with the partition wall (first support wall) 3a of the clutch housing case 3 sandwiched therein, and a forward / backward switching device (hydraulic clutch type). A gear transmission) 42 is provided.

Of these, the main transmission 41 is provided with four gear trains 44a, 45a, 44b, 45b, 44c, 45c, 44d, 45d that are constantly meshed between the first drive shaft 39 and the first select shaft 43, and is driven. Synchromesh sleeves 46a and 46b are provided between the paired gears 45a, 45b, 45c and 45d on the side so as to slide back and forth using a shift fork by artificial operation of the main shift lever, respectively.

Therefore, the main transmission 41 is composed of a mechanical gear transmission that shifts the rotation of the engine 2 to four stages and transmits the power of the engine 2 to the first select shaft 43. The first drive shaft 39 and the first select shaft 43 are pivotally supported by a partition wall 3a and an intermediate support plate (second support wall) 47 via bearings, of which the intermediate support plate 47 is a partition. It is separated from the wall 3a by a predetermined distance from the rear side and attached to the boss portion (not shown) integrally molded with the inner wall of the clutch housing case 3 from the rear side.

Further, as shown in FIGS. 3 and 4, the hydraulic clutch type forward / backward switching device 42 includes a rear portion of the first select shaft 43, a second drive shaft 48 connected to the rear portion of the select shaft 43, and a forward drive gear 49. A reverse drive gear 50 is provided. Further, the back shaft 51 is provided with an idle gear 52 that meshes with the reverse drive gear 50 so as to be idle. Further, a shuttle shaft (transmission shaft) 53 including a forward hydraulic clutch F and a reverse hydraulic clutch R is provided.

An intermediate support plate (second support wall) 47 is provided at the rear end of the first select shaft 43, the rear end portion of the second drive shaft 48 connected to the rear portion of the select shaft 43, and both ends of the shuttle shaft 53. The clutch housing case 3 is pivotally supported on the rear support plate (third support wall) 54, which is attached to the rear end surface of the clutch housing case 3 by a bearing, at a predetermined distance from the intermediate support plate 47. Further, the rear end portion of the back shaft 51 is attached to the rear support plate 54 so as to prevent rotation.

The forward hydraulic clutch F and the reverse hydraulic clutch R are composed of a two-pack type wet multi-plate clutch 55, and the wet multi-plate clutch 55 is a clutch that splines and connects the boss portion 55b to the shuttle shaft 53. A drum 55a is provided, and clutch hubs 55d and 55d are provided in front of and behind the flange portion 55c provided in the center of the clutch drum 55a.

Further, clutch plates 55e and 55f are provided which are respectively engaged with the spline portion provided inside the clutch drum 55a which opens back and forth and the spline portion formed on the clutch hub 55d and are arranged alternately in the axial direction thereof. Further, the front and rear pistons 55g facing the clutch plates 55e and 55f and the return spring 55h of the piston 55g are provided in the clutch drum 55a, respectively.

The front and rear clutch hubs 55d are integrally provided with a forward driven gear 56 and a reverse driven gear 57, and are supported on the shuttle shaft 53 via bearings. Further, the forward driven gear 56 always meshes with the above-mentioned forward drive gear 49, the reverse driven gear 57 meshes with the idle gear 52, and the front and rear clutch hubs 55d and 55d rotate forward and reverse.

Then, when hydraulic oil is supplied to the oil chamber defined between the flange portion 55c of the clutch drum 55a and the piston 55g through the oil hole 55i provided in the boss portion 55b, the clutch plates 55e and 55f are axially pressure-welded. The torque is transmitted between the clutch hub 55d and the clutch drum 55a.

Therefore, when the hydraulic oil is supplied to the forward hydraulic clutch F, the forward rotation is transmitted to the shuttle shaft 53, and when the hydraulic oil is supplied to the reverse hydraulic clutch R, the reverse rotation is transmitted to the shuttle shaft 53, and the forward hydraulic clutch F is also transmitted. When the supply of hydraulic oil to the reverse hydraulic clutch R is cut off, the transmission to the shuttle shaft 53 is cut off, which constitutes the forward / backward switching device 42.

The boss portion 55b of the clutch drum 55a is provided with an oil hole 55j for lubrication. When the lubricating oil is supplied to the oil hole 55j, the lubricating oil lubricates the clutch plates 55e and 55f and then the clutch drum. It is discharged into the transmission case T from its open end through the spline groove of 55a. Further, the shuttle shaft 53 is provided with two oil supply holes 53a and 53b for supplying hydraulic oil to the forward hydraulic clutch F and the reverse hydraulic clutch R, and one oil supply hole 53c for supplying lubricating oil to both clutches. ..

Further, an ultra-low speed transmission 58 composed of a constant meshing gear transmission is provided between the rear support plate 54 of the clutch housing case 3 and the support wall 4a of the center case 4. That is, the ultra-low speed transmission 58 has two gear trains 61a to 61f that are constantly meshed between the third drive shaft 59 that pivotally supports the rear support plate 54 and the support wall 4a via bearings and the second select shaft 60. , 62a, 62b and the gears 61f, 62b provided on the second select shaft 60 are provided with a sleeve 63, whereby the ultra-low speed transmission main transmission 58 makes the rotation transmitted from the shuttle shaft 53 ultra-low speed and standard speed. The speed is changed to the second gear, and the transmission is transmitted to the second select shaft 60.

Further, an auxiliary transmission 65 composed of a constantly meshing gear transmission is provided between the front support plate 64 attached to the front surface of the differential case 5 with bolts and the partition wall 5a of the differential case 5. That is, the auxiliary transmission 65 pivotally supports the front support plate 64 and the partition wall 5a via bearings, and is constantly meshed between the sub-shaft 66 connected to the second select shaft 60 and the pinion shaft 67. A sleeve 70 operated by an auxiliary transmission lever is provided between the two gear trains 68a, 68b, 69a, 69b and the driven side gears 68b, 69b provided on the pinion shaft 67, whereby the auxiliary transmission 65 is the second select. The rotation transmitted from the shaft 60 is changed to two stages, low speed and high speed, and transmitted to the pinion shaft 67.

Then, the pinion shaft 67 operates the differential device 71 of the rear wheels 17 by the bevel gear 67a provided at the rear end, and further, the rear wheels 17 are operated via the left and right brakes and the rear axle 16 provided on the left and right rear axle cases. Drive or brake. Further, the gear 72 provided at the front end of the pinion shaft 67 transmits the engine power to the front wheel double speed device 73 built in the center case 4.

Further, the front wheel double speed device 73 includes a fourth drive shaft 74 that pivotally supports the rear support plate 54 and the front support plate 64 via bearings, a driven gear 75 that meshes with a gear 72 provided on the fourth drive shaft 74, and a drive. The gears 76 and 77, the QT shaft 79 that pivotally supports the lid 78 that closes the opening provided on the bottom surface of the center case 4 via a bearing, and the drive gears 76 and 77 that are rotatably supported by the QT shaft 79 and are always present. It is composed of the driven gears 80 and 81 that mesh with each other and a two-pack type wet multi-plate clutch 82 similar to the hydraulic clutch provided in the forward / backward switching device 42.

When the hydraulic oil is not supplied to both the front and rear hydraulic clutches of the wet multi-plate clutch 82, the QT shaft 79 is not driven and the tractor 1 is in a two-wheel drive state in which only the rear wheels 17 are driven. When hydraulic oil is supplied to the front hydraulic clutch, the QT shaft 79 is driven at a standard speed, and then the 4WD shaft 83 connected to the QT shaft 79, the propeller shaft 84, and the front wheels 12 built in the front axle case 11 A four-wheel drive state is established in which the front wheels 12 are driven at substantially the same peripheral speed as the peripheral speeds of the rear wheels 17 via the differential device, the front axle 14, and the like.

On the other hand, when hydraulic oil is supplied to the hydraulic clutch on the rear side, the QT shaft 79 is driven at double speed, and then the difference between the 4WD shaft 83 connected to the QT shaft 79, the propeller shaft 84, and the front wheels 12 built in the front axle case 11. A double-speed drive state is established in which the front wheels 12 are driven at a peripheral speed that is approximately twice the peripheral speed of the rear wheels 17 via a moving device, a front axle 14, and the like. In the double speed drive state, for example, when the front wheels 12 are steered to a predetermined turning angle or more, the tractor 1 is automatically switched from the four-wheel drive state, whereby the tractor 1 can be turned in a small turn.

The traveling system transmission device installed in the transmission case T has been described above. Next, the PTO system transmission device installed in the transmission case T will be briefly described. That is, the PTO drive shaft 40 to which the power of the engine 2 is transmitted extends from the clutch housing case 3 to the rear part of the differential case 5, but in the center case 4 in the middle, the PTO clutch 85 is used. Dress up.

The PTO clutch 85 is composed of a single wet multi-plate clutch. When the hydraulic oil is supplied, the PTO clutch 85 is engaged, and when the hydraulic oil is not supplied, the PTO clutch 85 is disengaged. Further, a drive shaft 87 and a PTO shaft (power take-off shaft) 22 that are pivotally supported via a bearing between the partition wall 5b on the rear side of the differential case 5 and the lid 86 that closes the opening on the rear surface, and the partition wall. A return PTO shaft 89 that rotatably supports the idle gear 88 is attached between the 5b and the lid 80 so as not to rotate.

Further, four gear trains 90a, 90b, 91a, 91b, 92a, 92b, 91a, 88, 93 that constantly mesh with these shafts, and a pair of gears 90b on the driven side provided on the PTO shaft (power take-off shaft) 22. Sleeves 94 and 95 operated by the PTO shift lever are provided between 93, 91b and 92b, respectively, thereby forming the PTO transmission 96.

Then, the PTO transmission 96 shifts the engine rotation to three forward rotations and one reverse rotation, and transmits power from the rear end of the PTO shaft 22 toward the work equipment. It should be noted that the PTO-based transmission device described above constitutes an independent PTO capable of independently rotating and stopping the PTO shaft 22 by interrupting the PTO clutch 85 by a solenoid valve regardless of the traveling state. ..

Next, the hydraulic circuit of the tractor 1 will be described with reference to FIG. 5. The two hydraulic pumps 97 and 98 that are attached to the engine 2 and driven are oil filters from the differential case 5 of the transmission case T that functions as a hydraulic oil tank. The hydraulic oil is sucked through the hose provided along the right side of the transmission case T via 99. Further, one of the hydraulic pumps 97 can guide the hydraulic oil to the hydraulic take-out block 100 attached to the right side wall near the front of the clutch housing case 3 by piping, and supply the hydraulic oil to the external hydraulic equipment from the hydraulic take-out block 100. To make it.

Further, hydraulic oil is guided from the hydraulic take-out block 100 to the flow divider valve 101 attached to the right side wall of the hydraulic housing 20 by piping, and although not shown below, the front wheel double speed device is connected from this flow divider valve via a 3-position electromagnetic direction switching valve. The wet multi-plate clutch 82 of 73 is operated. Further, the hydraulic oil is guided from the flow divider valve 101 to the priority valve also attached to the right side wall of the hydraulic housing 20 by piping.

Then, the lift cylinder that rotates the lift arm 21 is operated from this priority valve via the electromagnetic control valve, or the lift rod cylinder that is interposed in either the left or right lift rod is connected to the left or right lift rod via the three-position electromagnetic direction switching valve. Activate. Further, the other hydraulic pump 98 guides hydraulic oil to the diversion valve 102 by piping, and the diversion valve 102 is located above the partition wall (first support wall) 3a of the clutch housing case 3. It is attached to the valve block 103 attached to the upper surface of the.

Further, hydraulic oil is guided from one of the flow dividing valves 102 to the hydraulic control valve attached to the valve block 103 via the internal oil passage provided in the valve block 103, and the wet multi-advance switching device 42 is wetted through the hydraulic control valve. The hydraulic oil is supplied to the forward hydraulic clutch F and the reverse hydraulic clutch R composed of the plate clutch 55 from the outlet ports P1 and P2 of the valve block 103. The hydraulic control valve is composed of an electromagnetic proportional pilot pressure reducing valve 104, and two electromagnetic proportional pilot pressure reducing valves 104 are used for the forward hydraulic clutch F and the reverse hydraulic clutch R.

Similarly, the hydraulic oil branched from one of the flow dividing valves 102 is guided to the IND valve assembly 105 attached to the right wall of the center case 4 by piping, and the PTO clutch is passed through the two-position electromagnetic direction switching valve 106 of the IND valve assembly 105. Operate 85. The relief valve 107 of the IND valve assembly 105 supplies the surplus oil to the PTO clutch 85 as lubricating oil.

Further, the hydraulic oil diverted from the other side of the flow dividing valve 102 is guided to the orbit roll type power steering unit A by a hose, the power steering unit A is operated by the steering wheel 15, and the power steering unit A is operated by the hose. The front wheels 13 are steered by operating the double-acting power steering cylinder 108 to be connected.

The return hose 109 of the power steering unit A branches 109a in the middle of the branch, and one of them supplies return oil to the needle bearings supporting the driven side gears 45a to 45d of the main transmission 41, whereby the gear 45a Forcibly lubricate the support part of ~ 45d.

Further, the other side of the return hose 109 of the power steering unit A returns to the valve block 103 once, and the return oil is once returned from the outlet port P3 of the valve block 103 to the forward hydraulic clutch F and the reverse hydraulic clutch of the forward / backward switching device 42. It is supplied to R as a lubricating oil. The surplus oil from the relief valve 110 that compensates for the pressure of the return oil of the power steering unit A as the lubricating oil and the oil discharged from the forward hydraulic clutch F and the reverse hydraulic clutch R are merged into the transmission case T. Discharge.

Next, hydraulic oil and lubricating oil are supplied from the valve block 103 provided with the hydraulic control valve (electromagnetic proportional pilot pressure reducing valve 104), which is a feature of the present invention, to the forward hydraulic clutch F and the reverse hydraulic clutch R of the forward / backward switching device 42. The oil passage will be described. That is, as shown in FIGS. 6 to 9, two outlet ports P1 and P2 for supplying hydraulic oil to the forward hydraulic clutch F and the reverse hydraulic clutch R provided on the lower surface of the valve block 103, and one for supplying lubricating oil. The outlet port P3 is joined to the inlet ports of the three oil feeding holes 111 (111a, 111b, 111c) bored in the partition wall (first support wall) 3a of the clutch housing case 3 in the vertical direction to communicate with each other. Let me.

Further, mounting holes 3b and 47a are provided on the rear surface side of the partition wall (first support wall) 3a of the clutch housing case 3 and the front surface side of the intermediate support plate (second support wall) 47, respectively, and the front and rear mounting holes are provided. The oil passage shaft 112 is inserted into 3b and 47a in the front-rear direction, and the oil passage shaft 112 is erected over the partition wall 3a and the intermediate support plate 47. The mounting holes 3b and 47a are provided in the boss portions protruding from the respective wall surfaces, and the back sides of the mounting holes 3b and 47a are closed by the wall.

As shown in FIG. 10, the oil passage shaft 112 has three lateral holes 112a, 112b, and 112c formed in the axial direction by machining, and two lateral holes 112a, 112b, and 112c formed on the outer peripheral surface near the left end and the right end, respectively. Circumferential grooves 112d, 112e, 112f, 112g, two vertical holes 112h, 112i, 112j, 112k communicating from the annular groove to the horizontal hole, and O-ring mounting grooves 112l, 112m, 112n provided on the left and right sides of the annular groove. , 112o, 112p, 112q are provided three on each side.

Further, the outlet ports of the three oil supply holes 111 bored in the partition wall 3a of the clutch housing case 3 in the vertical direction have the innermost portion 3c (oil reservoir portion) of the mounting hole 3b and the oil passage shaft 112. It opens at a position communicating with the annular grooves 112d and 112e when it is inserted. When inserting the oil passage shaft 112 into the mounting hole 3b, the O-ring 113 is inserted into the O-ring mounting groove, and the oil-tightened portion between the oil reservoir 3c of the mounting hole 3b and the respective annular grooves 112d and 112e is oil-tightened. Further, the outlet ports of the oil supply holes 111a and 111b through which the O-ring 113 passes when the oil passage shaft 112 is inserted are rounded to prevent damage to the O-ring 113.

Further, after inserting the front end side of the oil passage shaft 112 into the mounting hole 3b of the partition wall 3a, the intermediate support is provided from the rear side so that the rear end side of the oil passage shaft 112 fits into the mounting hole 47a of the intermediate support plate 47. Attach the plate 47 to it. Then, in the mounting hole 47a of the intermediate support plate 47 as well as the mounting hole 3b of the partition wall 3a, the position facing the innermost portion 47b (oil reservoir portion) of the mounting hole 47a and the annular groove 112f, 112g of the oil passage shaft 112. Is provided with three oil feeding holes 114 (114a, 114b, 114c) inlet ports.

Therefore, the hydraulic oil and the lubricating oil derived from the three oil feeding holes 111 provided in the partition wall 3a of the clutch housing case 3 are the horizontal holes 112a, 112b, 112c and the vertical holes 112h, 112i, 112j provided in the oil passage shaft 112. , 112k, and are guided to the inlet ports of the three oil feed holes 114 of the intermediate support plate 47 through the three oil feed holes.

The oil passage shaft 112 has left and right annular grooves 112d, 112e, 112f, and 112g formed at substantially the same dimension distance from each end face of the oil passage shaft 112. Therefore, even if the oil passage shaft 112 is installed in the front and rear mounting holes 3b and 47a in the opposite directions, the three oil feeding holes 111 and the intermediate support plate 47 provided in the partition wall 3a of the clutch housing case 3 are fed. The communication relationship with the oil hole 114 is maintained, hydraulic oil and lubricating oil can be supplied to the forward hydraulic clutch F and the reverse hydraulic clutch R without any trouble, and the direction of the oil passage shaft 112 can be adjusted in the assembly process. There is no need to consider it, and the assemblability is improved.

Further, the lateral holes 112a, 112b, 112c provided in the oil passage shaft 112 are provided with mounting holes 112r for plugs larger than the inner diameter of the lateral holes, and the plug 115 is attached to the mounting holes 112r to close the ends. The end that is not closed by the plug 115 is not provided with a mounting hole 112r, which makes it impossible to mount the plug 115. Therefore, it is possible to prevent the plug 115 from being erroneously attached in the assembly process of the oil passage shaft 112.

More specifically, the three oil supply holes 111 provided in the partition wall 3a of the clutch housing case 3, the three oil supply holes 114 of the intermediate support plate 47, and the three lateral holes 112a provided in the oil passage shaft 112 between them. As shown in the schematic diagram of FIG. 11, three methods of communicating with the 112b and 112c can be considered on the premise that the oil passage shaft 112 can be oriented upside down without any problem.

For example, in the case of (a) shown in the embodiment of the present invention, the lubricating oil is set in this order from the front, the hydraulic oil of the forward hydraulic clutch F, and finally the hydraulic oil of the reverse hydraulic clutch R. It is determined whether or not the plug mounting holes 112r are provided in the lateral holes 100a, 100b, and 100c, and whether or not the plug 115 is mounted. Further, when the oil passage shaft 112 is determined in this way, the lubricating oil and the hydraulic oil can be guided in the initially set order even when the direction of the oil passage shaft 112 is reversed in the front-rear direction (a').

Even if the remaining two communication methods are adopted, the lubricating oil and the hydraulic oil can be guided without any trouble even when the direction of the oil passage shaft 112 is reversed in the front-rear direction. Therefore, these Any method may be used to determine whether to provide two plugs 115 on each side at the ends of the lateral holes 112a, 112b, 112c.

Even if the oil passage shaft 112 is provided with three annular grooves and three vertical holes on the left and right, and all the plugs 115 are attached to the ends of the horizontal holes 100a, 100b, and 100c, the lubricating oil and the hydraulic oil can be guided without any problem. However, in this case, the number of annular grooves, vertical holes, and O-ring mounting grooves increases, the processing man-hours increase, and the number of plugs 115 and O-rings 113 used increases, which may increase the cost and is difficult to adopt. It becomes.

Next, the oil passage that leads the hydraulic oil and the lubricating oil to the forward hydraulic clutch F and the reverse hydraulic clutch R from the oil supply hole 114 of the intermediate support plate 47 will be described. As shown in FIG. 7, the rear end of the oil passage shaft 112 is The mounting hole 47a for mounting is formed in the boss portion 47c protruding to the front side of the intermediate support plate 47. Further, the shuttle shaft 53 of the forward / backward switching device 42 is provided with a hydraulic control inheritance portion extending from the shaft support portion on the front end side thereof, and further, an accommodating hole provided inside the boss portion 47c protruding to the front side of the intermediate support plate 47. The hydraulic transfer part is housed in.

Then, a connecting wall portion 47e connecting the boss portion 47c of the intermediate support plate 47 and the other boss portion 47d is provided on the intermediate support plate 47, and three oil feeding holes 114 of the intermediate support plate 47 are provided inside the connecting wall portion 47e. To pierce. Then, the outlet port of the oil supply hole 114 is provided in the accommodation hole accommodating the oil pressure inheritance portion of the shuttle shaft 53, and communicates with the oil supply holes 53a, 53b, 53c of the shuttle shaft 53.

The communication method at that time is the communication method between the three oil feeding holes 111 provided in the partition wall 3a of the clutch housing case 3 and the three lateral holes 112a, 112b, 112c provided in the oil passage shaft 112 described above. Since the same is true, the illustration and description will be omitted. Further, the oil passage for supplying the hydraulic oil and the lubricating oil to the forward hydraulic clutch F and the reverse hydraulic clutch R is completed by the above, and incidental matters in configuring the oil passage will be described below.

That is, the oil passage shaft 112 is provided inside the clutch housing case 3, but the clutch housing case 3 provided with the oil passage shaft 112 is equipped with a main transmission 41, and the oil passage shaft 112 is the main transmission 41 and the like. It is necessary to install it at a position that does not interfere with.

Therefore, in this case, the first drive shaft 39 of the main transmission 41 is closer to the center of the upper part of the clutch housing case 3, the first select shaft 43 is closer to the right side below it, and the sleeves 46a and 46b. Since the rail 117 of the shift fork 116 for operating the above is located on the lower left side, the oil passage shaft 112 is arranged on the left side above the rail 117, which is a relatively empty space, to prevent interference with these transmissions. ..

However, since the shift fork 116 that operates the sleeve 46b on the rear side interferes with the boss portion 47d that protrudes to the front side of the intermediate support plate 47, only this shift fork 116 is changed to a shape that bypasses the lower part of the boss portion 47d. Correspond.

Since the tractor 1 configured as described above changes the forward / backward switching device, which had been mechanically configured until then, to a hydraulic clutch type, the forward / backward switching is performed when the work is frequently performed forward and backward. Only by operating the lever 32, the clutch pedal 34 can be operated without depressing the clutch pedal 34, and the fatigue associated with the work can be reduced and the work can be performed efficiently.

In addition, since only the clutch part of the forward / backward switching device is changed to a hydraulic clutch and the transmission mode is almost the same, it can be used in combination with a conventional transmission and a transmission case, and a significant cost reduction can be achieved. ..

Further, a valve block 103 provided with a control valve for the hydraulic clutches F and R is provided on the upper surface of the clutch housing case 3 having excellent maintainability, and is newly piped to the hydraulic clutches F and R provided at a location away from the valve block 103. By changing from the conventional external piping to the internal piping in order to supply the hydraulic oil, it is possible to construct an inexpensive and reliable oil passage.

In the embodiment described above, the hydraulic clutch for supplying hydraulic oil using the oil passage shaft 112 is the forward hydraulic clutch F and the reverse hydraulic clutch R of the forward / backward switching device. For example, a conventional external pipe is used. The PTO clutch 85 for supplying hydraulic oil or the wet multi-plate clutch 82 of the front wheel double speed device 73 may be used, or when the main / sub transmission device or the PTO transmission device to be mechanical type is a hydraulic clutch type, these It can be used as a piping structure for hydraulic oil for a hydraulic clutch.

Further, the partition wall 3a on which the oil passage shaft 112 is erected and the intermediate support plate 47 may be a wall integrally molded inside the transmission case T or a mounting plate to be retrofitted. However, due to the configuration of the transmission, both of them are used. The wall may be integrally molded, or may be a mounting plate to be retrofitted, and the present invention is not limited to the above embodiment.

1 Tractor (working vehicle)
3a partition wall (first support wall)
42 Forward / backward switching device (gear transmission)
47 Intermediate support plate (second support wall)
53 Shuttle shaft (transmission shaft)
98 hydraulic pump 103 valve block
104 Electromagnetic proportional pilot pressure reducing valve (flood control valve)
112 Oil passage shaft T Transmission case F Forward hydraulic clutch (flood clutch)
R Reverse hydraulic clutch (flood clutch)

Claims (2)

A work vehicle in which hydraulic oil or lubricating oil pumped from a hydraulic pump is supplied to a hydraulic clutch built in a transmission case via a valve block equipped with a hydraulic control valve and a plurality of oil passages, and the gear transmission is changed by this hydraulic clutch. In the transmission case, the first support wall, the transmission shaft that supports the hydraulic clutch, the second support wall that supports one end of the transmission shaft, and the first and second support walls are erected. When a plurality of oil supply holes are formed in each of the oil passage shafts to be formed and the oil supply holes are communicated with each other to form a plurality of oil passages, a plurality of oil supply holes to be formed in the oil passage shaft are provided. , It is composed of a horizontal hole in the axial direction and a vertical hole that communicates with the horizontal hole from the annular groove formed near the left and right ends of the outer peripheral surface, and the left and right annular grooves have substantially the same dimensions from the respective end faces of the oil passage shaft. Even if the oil passage shafts are erected on the first and second support walls in the opposite directions, the hydraulic oil and the lubricating oil can be supplied to the hydraulic clutch without any trouble. a work vehicle, characterized in that constructed. A plug mounting hole larger than the inner diameter of the horizontal hole is provided at the end of the horizontal hole drilled in the oil passage shaft, and the plug is attached to the mounting hole to close the end, and the end not closed by the plug is a mounting hole. The work vehicle according to claim 1, wherein the work vehicle is configured so as to prevent the plug from being erroneously attached by disabling the attachment of the plug without providing the plug .

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