JPH0594059U - Work vehicle drive transmission structure - Google Patents

Abstract

(57) [Abstract] [Purpose] The first transmission gear for straight traveling and the second transmission gear for turning are arranged with respect to the pair of side gears that can be slidably operated on the left and right traveling devices, and the left and right side gears are arranged on the first side. Or, in the traveling power transmission structure of the work vehicle configured to perform the straight traveling and the turning operation by engaging with the second transmission gear, by the sliding operation of the transmission shaft in which the pair of third transmission gears are fixed to the left and right ends, 3rd power from the transmission shaft
In the case where the transmission gear is configured to be switchable between a gentle turning state in which low-speed forward rotation power is transmitted to the second transmission gear as low-speed power and a super-spindle rotation state in which reverse-speed power is transmitted to the second transmission gear, the transmission shaft The ends should not bend due to the transmission reaction force. [Structure] A holding portion 43a that rotatably engages and holds an end portion 24b of the transmission shaft 24 on the sliding direction side in association with a sliding operation to a gently swiveling position, and a sliding operation to a super-satellite swiveling position. , The end 24 on the sliding direction side of the transmission shaft 24
A holding portion 42a that rotatably engages and holds a is provided. As a result, the slide operation side of the transmission shaft 24 is held in both sides.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a traveling power transmission structure of a work vehicle equipped with a pair of left and right traveling devices of a multi-wheel type or a crawler type.

[0002]

[Prior Art]

 As an example of the work vehicle as described above, there is a combine equipped with a pair of left and right crawler type traveling devices. In such a combine, one selected traveling device is driven to rotate at a slower speed than the other to perform a gentle turn. In addition, there is a configuration in which one traveling device is driven in the reverse direction to perform super-spot turning. An example of such a turning structure is disclosed in Japanese Patent Laid-Open No. 4-46871. In this structure, when the left and right side gears (12 in FIG. 2 of the publication) are interlocked with the first transmission gear (7 in FIG. 2 of the publication) to which the forward rotation power for straight traveling is transmitted, the left and right side gears are connected. The forward rotation power of the same speed is transmitted from the vehicle to the left and right traveling devices, and the aircraft moves straight. When the left side gear is slid from this state as shown in FIG. 2 of the publication, the left side gear is linked to the second transmission gear (9 in FIG. 2 of the publication). In this case, if low-speed forward rotation power is transmitted to the second transmission gear, the left traveling device will be driven at a lower speed than the right traveling device, and the aircraft will slowly turn left due to the speed difference between the left and right traveling devices. I will do it. Then, if the reverse rotation power is transmitted to the second transmission gear, the left traveling device is driven in reverse rotation, and the airframe makes a super turning turn to the left.

In the above-mentioned conventional structure, the transmission shaft (24 in FIG. 3 of the above publication) is used for switching operation of transmitting low speed forward rotation power or reverse rotation power to the second transmission gear. It is carried out by the sliding operation of. As shown in FIG. 3 of the publication, when the transmission shaft is slid to the left side of the drawing, the power of the transmission shaft is changed from the left and right third transmission gears (11 in FIG. 3 of the publication) to the gear (the publication). 2), 28) of FIG. 3) and is transmitted to the second transmission gear in the reverse rotation state. On the contrary, when the transmission shaft is slid rightward on the paper surface, the third transmission gears on the left and right of the transmission shaft directly mesh with the second transmission gear, and the power of the transmission shaft moves to the second transmission gear at the low speed forward rotation state. It is transmitted.

[0004]

[Problems to be solved by the device]

 In the above-mentioned structure, since the third transmission gear is provided at both ends of the transmission shaft that is slid, the two supporting portions between the left and right third transmission gears (the sleeve 38 in FIG. 3 of the above publication) are used. The transmission shaft is slidably supported, and the third transmission gears at both ends of the transmission shaft are cantilevered. Therefore, when the power is transmitted from the left and right third transmission gears to the second transmission gear, the end portion of the transmission shaft (the portion supporting the third transmission gear) is caused by the transmission reaction force generated at the meshing portion of the gear teeth. It may bend. In this case, as shown in FIG. 3 of the above-mentioned publication, when the transmission shaft is slid to the left side of the drawing, one that is largely protruding from the supporting portion, such as the end of the transmission shaft on the left side of the drawing. The end of the transmission shaft is easily bent. When the end portion of the transmission shaft bends in this way, a thrust force along the axial direction is generated together with the aforementioned transmission reaction force during transmission. Then, the thrust force may push the transmission shaft in the axial direction little by little, and finally the third transmission gear may be disengaged from the reverse rotation gear or the second transmission gear. According to the present invention, as described above, the operation of the work vehicle configured to perform the switching operation of transmitting the low speed forward rotation power or the reverse rotation power to the second transmission gear by the sliding operation of the transmission shaft is performed. The purpose is to prevent the transmission structure from sliding the transmission shaft by the thrust force and disengaging the third transmission gear from the reverse rotation gear or the second transmission gear.

[0005]

[Means for Solving the Problems]

 A feature of the present invention is that the traveling power transmission structure of the work vehicle as described above is configured as follows. In other words, a transmission shaft having a pair of third transmission gears fixed to both left and right ends is slidably supported at at least two positions between the left and right third transmission gears, and the power from the transmission shaft is transmitted to the pair of third transmission gears. A gentle turning position in which the gear transmits low speed forward rotation power to the pair of second transmission gears, and a field rotation in which power from the transmission shaft is transmitted from the pair of third transmission gears to the pair of second transmission gears as reverse rotation power. A holding portion that is configured to slide the transmission shaft forward and backward over the position, and that rotatably engages and holds the end of the transmission shaft on the sliding direction side when the slide operation is performed to the gently swung position. Also, a holding portion is provided that rotatably engages and holds the end portion of the transmission shaft on the sliding direction side in association with the sliding operation to the pivot position.

[0006]

[Action]

 When configured as described above, it is assumed that, for example, as shown in FIG. 1, the transmission shaft 24 is operated to the leftward turning position in the drawing. In this case, the end portion 24a on the left side of the paper surface of the transmission shaft 24 is held by the holding portion 42a on the left side of the paper surface, and the right end portion 24b of the transmission shaft 24 on the paper surface is separated from the holding portion 43a on the right side of the paper surface. In this state, the power of the transmission shaft 24 is transmitted from the third transmission gear 11 to the second transmission gear 9 in the reverse rotation state. In this case, the left side of the transmission shaft 24, which largely protrudes from the original supporting portion (the portion of the left sleeve 38 in FIG. 1), is supported by the original supporting portion and the holding portion 42a in a double-supported state. As a result, even if a transmission reaction force acts on the third transmission gear 11 on the left side of the paper surface, the left side of the transmission shaft 24 on the paper surface does not bend. On the contrary, it is assumed that the transmission shaft 24 is operated to the right turning position on the right side of the drawing. In this case, the end portion 24b on the right side of the paper surface of the transmission shaft 24 is held by the holding portion 43a on the right side of the paper surface, and the end portion 24a of the transmission shaft 24 on the left side of the paper surface is separated from the holding portion 42a on the left side of the paper surface. In this state, the power of the transmission shaft 24 is transmitted from the third transmission gear 11 to the second transmission gear 9 in a low speed forward rotation state. In this case, the right side of the transmission shaft 24, which largely protrudes from the original supporting portion (the portion of the sleeve 38 on the right side in FIG. 1), is supported by the original supporting portion and the holding portion 43a in a double-supported state. As a result, even if a transmission reaction force acts on the third transmission gear 11 on the right side of the paper surface, the right side of the transmission shaft 24 on the paper surface does not bend.

In contrast to the configuration of the present invention, it may be considered that the left and right ends of the transmission shaft are always held at both ends even when the transmission shaft is slid. However, in this case, the left and right ends of the transmission shaft and the holding part are long along the sliding operation direction so that the left and right ends of the transmission shaft are supported by the holding part over the entire range of the sliding operation of the transmission shaft. It has to be organized into things. On the other hand, in the configuration of the present invention, when the transmission shaft is slid, the end opposite to the sliding direction is not held in the two-sided state by separating the end of the transmission shaft from the holding portion. Therefore, it is not necessary to configure the left and right ends of the transmission shaft and the holding portion to be long along the slide operation direction, and the length may be such that at least the end portion of the transmission shaft on the sliding direction side is held by the holding portion. .. In the case of the present invention, the side opposite to the sliding direction is not a cantilever state but a cantilever state, but as shown in FIG. 1, for example, on the side opposite to the sliding direction (see the right side of the drawing), the transmission is performed. The end portion 24b of the shaft 24 does not project much from the original support portion (the portion of the sleeve 38 on the right in FIG. 1). Therefore, even if the side opposite to the sliding direction is cantilevered, the bending of the transmission shaft is unlikely to occur at this portion.

[0008]

[Effect of the device]

 As described above, by suppressing the deflection of the transmission shaft near the third transmission gear and suppressing the generation of thrust force along the axial direction, it is possible to prevent the transmission shaft from slipping from the gentle turning position and the ground turning position. As a result, it is possible to prevent damages caused by the transmission shaft moving out of the gentle turning position and the ground turning position, and improve the reliability of the traveling transmission structure of the work vehicle. .. When the transmission shaft is slid, at least the side that largely projects from the original support portion is held in a double-supported state so that the end of the transmission shaft does not need to be made longer than necessary, so the overall structure It is also advantageous in terms of downsizing.

[0009]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows the structure inside the mission case 2 of the traveling system of the combine, which is one of the work vehicles. The power from the engine (not shown) is provided with a belt transmission mechanism (not shown) equipped with a tension clutch. It is transmitted to the input pulley 16 of the hydrostatic continuously variable transmission M via. Power from the output shaft 1 of the hydrostatic continuously variable transmission M is transmitted from the first transmission shaft 14 to the reaper (not shown) via the output pulley 15.

Power from the output shaft 1 is transmitted to the second transmission shaft 21 via the first gear 10. A first high speed gear 22 is fitted onto the second transmission shaft 21 so as to be relatively rotatable, and a shift gear 3 is slidably mounted in a spline structure. A low speed gear 25, a medium speed gear 8 and a second high speed gear 23 are attached to the third transmission shaft 24 (corresponding to the transmission shaft which is a feature of the present invention) by a spline structure, and the first and second high speed gears 22 are provided. , 23 are occluded. As a result, by sliding the shift gear 3 to engage with the first high speed gear 22, the medium speed gear 8 and the low speed gear 25, the power can be shifted to three stages of high, medium and low, and this power is transmitted to the medium speed gear 8. It is transmitted to the first transmission gear 7 that engages.

The right and left side gears 12 are relatively rotatably fitted onto the support shaft 6 supporting the first transmission gear 7, and the input gears 18 of the left and right axles 5 are constantly meshed with the left and right side gears 12. There is. As a result, an occlusal first clutch FC is configured between the right or left side gear 12 and the first transmission gear 7, and the convex engagement portion 13 of the side gear 12 is engaged with the first transmission gear 7. Thus, the forward rotation power for straight traveling is transmitted to the left and right crawler type traveling devices 4. The spring 19 biases the side gear 12 toward the first transmission gear 7 side.

A pair of second transmission gears 9 are externally fitted to the left and right of the support shaft 6, and a multi-plate friction type second clutch RC is provided between the second transmission gear 9 and the side gear 12. On the other hand, as shown in FIGS. 1 and 2, the third transmission gears 11 are fixed to both ends of the third transmission shaft 24, and the left and right third bearings between the left and right third transmission gears 11 are used for bearings. A sleeve 38 is fitted inside the pair of bear rings 31, and the third transmission shaft 24 is slidably supported on the left and right sleeves 38 left and right. In this case, since the low speed gear 25 and the medium speed gear 8 are supported by the third transmission shaft 24 in a spline structure and are positioned by the sleeve 26, even if the third transmission shaft 24 is slid, the low speed gear 25 is rotated. The positions of 25 and the medium speed gear 8 do not change, and the power from the second transmission shaft 21 is normally transmitted to the third transmission shaft 24 by the low speed gear 25 and the like.

As shown in FIG. 1, the shift shaft 29 is slidably supported in the left-right direction of the paper in the mission case 2, and the shift fork 30 is fixed to the tip of the shift case 29. The shift fork 30 is engaged in the return groove of the. Then, as shown in FIG. 2, a manipulating type switching lever 32 provided in the control section of the machine body and the shift shaft 29 are mechanically interlocked by a linkage mechanism 41, and by the switching lever 32. Through the shift shaft 29 and the shift fork 30, the third transmission shaft 24 is slid to the left and right in the drawing.

As shown in FIGS. 1 and 2, a pair of side cases 42, 43 are attached to the left and right side surfaces of the mission case 2. The side cases 42 and 43 support the ends of the fourth transmission shaft 39 and the support shaft 6 which will be described later as bearings, and have concave portions at the portions facing the left and right ends 24a and 24b of the third transmission shaft 24. 42a and 43a (corresponding to a holding portion) are provided. A pair of fourth transmission shafts 39 are supported on the left and right of the transmission case 2, the second gear 27 and the third gear 28 are fixed to the fourth transmission shaft 39, and the left and right third gears 28 are the second. The transmission gears 9 are in mesh with each other.

With the structure described above, when the switching lever 32 is operated to the super-spinning turning position and the third transmission shaft 24 is slid to the left side of the drawing, first, the end 24 of the third transmission shaft 24 on the left side of the drawing is moved. a is inserted into and supported by the recess 42a of the side case 42 on the left side of the drawing. Then, next, the left and right third transmission gears 11 mesh with the left and right second gears 27, and the end portion 24b on the right side of the paper of the third transmission shaft 24 comes out from the recess 43a of the side case 43 on the right side of the paper. ..

As a result, the power of the third transmission shaft 24 is transmitted to the left and right second transmission gears 9 in the reverse rotation state via the second gear 27, the fourth transmission shaft 39 and the third gear 28. Therefore, for example, when the left side gear 12 is operated away from the first transmission gear 7 and the second clutch RC is pressed in and out by the pressing portion 17 of the left side gear 12, the reverse rotation power of the left second transmission gear 9 is left. The signal is transmitted to the traveling device 4 of FIG.

On the contrary, when the switching lever 32 is operated to the gentle turning position and the third transmission shaft 24 is slid rightward on the paper surface, first, the end 24b on the right side of the paper surface of the third transmission shaft 24 is moved to the right side on the paper surface. The side case 43 is supported by being inserted into the recess 43a. Then, next, the left and right third transmission gears 11 directly engage with the left and right second transmission gears 9, and the end portion 24a on the left side of the paper of the third transmission shaft 24 comes out from the recess 42a of the side case 42 on the left side of the paper. ..

As a result, the normal rotation power that is lower than the normal rotation power transmitted from the third transmission shaft 24 to the first transmission gear 7 is transmitted from the third transmission shaft 24 to the second transmission gear 9. Therefore, for example, when the left side gear 12 is separated from the first transmission gear 7 and the second clutch RC is pressed and operated by the pressing portion 17 of the left side gear 12, the left traveling device 4 moves at a lower speed than the right traveling device 4. The vehicle is driven to rotate in the normal direction, and the aircraft gently turns to the left due to the speed difference between the left and right traveling devices 4.

Next, the sliding operation structure of the left and right side gears 12 will be described. As shown in FIGS. 3 and 2, an operating arm 20 for sliding operation of the left and right side gears 12 and a hydraulic cylinder 33 (corresponding to operating means) for rocking the operating arm 20 are provided. In this case, the hydraulic cylinder 33 is internally provided with a spring (not shown) for urging the hydraulic cylinder 33 toward the contraction side, and the hydraulic oil from the pump 34 is supplied to the electromagnetically operated control valve 35 for the hydraulic cylinder 33. Has been done. When the side gear 12 is separated from the first transmission gear 7 (the first clutch FC is in the disengaged state) and the hydraulic cylinder 33 extends until it moves to the neutral stop position where the second clutch RC is not pressed and operated, the hydraulic cylinder 33 A drain oil passage 36 is provided for draining hydraulic oil from the tank to stop the hydraulic cylinder 33 at the neutral stop position, and the drain oil passage 36 is provided with a variable relief valve 37.

Next, the operation of the control valve 35 and the variable relief valve 37 will be described. The state shown in FIGS. 3 and 2 is a straight traveling state in which the left and right side gears 12 mesh with the first transmission gear 7. If the operating lever 40 is operated to the left first turning position L1 from this state, for example, only the control valve 35 is switched and operating oil is supplied to the left hydraulic cylinder 33, so that the left side gear 12 moves to the left side of the drawing. Slides away from the first transmission gear 7 (the first clutch FC is in the disengaged state). In this case, since the variable relief valve 37 is fully open, the drain oil passage 36 opens at the neutral stop position before the left side gear 12 presses the second clutch RC, and hydraulic oil escapes from the variable relief valve 37. The left side gear 12 stops at this neutral stop position. This is the state where the transmission to the left traveling device 4 is cut off, and the aircraft gently turns to the left.

When the operating lever 40 is operated to the second left turning position L2, the variable relief valve 37 is throttled, the hydraulic cylinder 33 is extended from the neutral stop position, and the second left clutch RC is completely released. Entered and operated. In this case, as shown in FIG. 2, if the switching lever 32 is operated to the super-spinning position, and the third transmission gears 11 on the left and right of the third transmission shaft 24 are engaged with the second gear 27. , The left traveling device 4 is driven in the reverse direction and super-turning is possible. Further, when the operation lever 40 is operated between the left first turning position L1 and the second turning position L2, the hydraulic oil is drained from the hydraulic cylinder 33 from the above-mentioned state, and the pressing force on the second clutch RC is weakened. Be done. As a result, the second clutch RC slips and the reverse rotation speed of the left traveling device 4 can be changed.

On the contrary, if the switching lever 32 is operated to the gentle turning position and the third transmission gears 11 on the left and right of the third transmission shaft 24 are directly engaged with the second transmission gear 9, the operation lever 40 is moved to the left. When the vehicle is operated to the second turning position L2, the left traveling device 4 is driven to rotate in the forward direction at a low speed, and a gentle turning can be performed. Further, when the operating lever 40 is positioned between the left first and second turning positions L1 and L2, the second clutch RC slips and the low forward rotation speed of the left traveling device 4 can be changed as described above. .. The above operation is similarly performed at the right first turning position R1 and the second turning position R2.

[Other Embodiments] In the above-described embodiments, the side cases 42, 43 are provided with the recesses 42a, 43a, and the end portions 24a, 24b of the third transmission shaft 24 are inserted into the recesses 42a, 43a. However, at the end portions 24a, 24b of the third transmission shaft 24, conical concave portions are formed on the end surfaces thereof, and conical convex portions are provided on the side cases 42, 43. The convex portion may be engaged with the concave portion of the third transmission shaft 24 to support the end portion of the third transmission shaft 24. In the embodiment of FIG. 2, the first clutch FC is an articulating type and the second clutch RC is a rubbing type, but the first clutch FC is a friction type and the second clutch RC is an articulating type. Alternatively, both the first and second clutches FC and RC may be occlusal type, or both the first and second clutches FC and RC may be frictional type.

It should be noted that reference numerals are added to the claims of the utility model for convenience of comparison with the drawings, but the invention is not limited to the configuration of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of the vicinity of a third transmission shaft and a second transmission gear.

FIG. 2 is a schematic diagram showing a transmission structure in a mission case.

FIG. 3 is a hydraulic circuit diagram for sliding operation of left and right side gears.

[Explanation of symbols]

 4 Traveling device 7 1st transmission gear 9 2nd transmission gear 11 3rd transmission gear 12 Side gear 24 Transmission shafts 24a, 24b End of transmission shaft 33 Operation means 42a, 43a Holding part

Claims (1)

[Scope of utility model registration request] 1. A first transmission gear (7) in which forward rotation power for straight traveling is transmitted to each of a pair of left and right side gears (12) which transmits power to each of a pair of left and right traveling devices (4). ) And a pair of left and right second transmission gears (9) to which low-speed forward rotation power or reverse rotation power is transmitted, and each of the left and right side gears (12) is connected to the first transmission gear (7). A traveling power transmission structure for a work vehicle, comprising: operating means (33) independently slidable between an interlocking connection position with and a second interlocking position with the second transmission gear (9). A transmission shaft (24) having a pair of third transmission gears (11) fixed to both ends is slidably supported at least at two positions between the left and right third transmission gears (11), and the transmission shaft (24 ) Power from a pair of third transmission gears (11)
From the pair of second transmission gears (9) as a low speed forward rotation power to the pair of second transmission gears (9) and the pair of third transmission gears (11) as reverse rotation power from the pair of third transmission gears (11). The transmission shaft (24) is configured to be slidable in forward and reverse directions over the solid rotation position to be transmitted to the second transmission gear (9), and the transmission is performed in accordance with the sliding operation to the slow rotation position. A holding portion (43) which rotatably engages and holds the end portion (24b) of the shaft (24) on the sliding direction side.
a) and with the sliding operation to the pivot position, the end (24) of the transmission shaft (24) on the sliding direction side.
A traveling power transmission structure for a work vehicle including a holding portion (42a) for rotatably engaging and holding a).