JPH0594058U - Work vehicle drive transmission structure - Google Patents

Abstract

(57) [Summary] [Purpose] A low-speed forward rotation power is transmitted to one side gear so that the pair of left and right side gears for the left and right traveling devices mesh with the first transmission gear for straight movement to move the aircraft straight. To stop and hold the second transmission gear in the traveling power transmission structure of the work vehicle configured to interlock with the incoming second transmission gear and drive one of the traveling devices in the forward direction at a low speed to perform a gentle turn. In the case where it is configured such that one traveling device is stopped by one of the traveling devices to make a turning turn,
A switching structure for transmitting low-speed forward rotation power to a transmission gear and stopping and holding the second transmission gear is simply configured. A shift gear 32 for transmitting a low-speed forward rotation power to a second transmission gear 30 and an engagement position with the second transmission gear 30,
The shift fork 39 is configured to be slidable over a distance position away from the second transmission gear 30, and the engagement portion 39a provided on the shift fork 39 is engaged with the second transmission gear 30 at the separation position of the shift gear 32. Then, this is configured to be stopped and held.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a traveling power transmission structure of a work vehicle provided with a pair of left and right traveling devices such as a multi-wheel type with four wheels on each side and 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 traveling devices of a crawler type, and in such a combine, one selected traveling device is driven in reverse to make a super turning turn (or , One traveling device is driven at a lower speed than the other in the forward direction to make a gentle turn) and one traveling device is stopped to make a solid turning state. There is something. An example of such a turning switching structure is disclosed in Japanese Utility Model Laid-Open No. 3-72089. In this structure, when the left and right side gears (6 in FIG. 1 of the publication) are interlocked with the first transmission gear (15 in FIG. 1 of the publication) to which the forward rotation power for straight traveling is transmitted, The forward rotation power of the same speed is transmitted from the side gears to the left and right traveling devices (7 in FIG. 1 of the above-mentioned publication), and the machine body goes straight.

A second transmission gear (13 in FIG. 1 of the above publication) is arranged for the left and right side gears, and a gear (see FIG. 1 of the above publication) is slid by operating a shift gear (5 in FIG. 1 of the above publication). 11), the reverse power from this gear is transmitted to the second transmission gear via the shift gear. As a result, in this state, for example, if the left side gear is operated by sliding to be linked to the second transmission gear, the left traveling device is driven in the reverse direction and can be turned to the left. On the contrary, when the shift gear is engaged with the convex portion (3a in FIG. 1 of the publication) of the inner surface of the transmission case, the shift gear and the second transmission gear are fixed. Thus, in this state, for example, if the left side gear is slid and connected to the second transmission gear in an interlocking manner, the left traveling device is stopped and the vehicle can turn to the left. As described above, the switching operation between the super pivot turning state and the pivot turning state is configured to be performed by the sliding operation of the shift gear (5 in FIG. 1 of the above publication), and the second operation is performed via the shift gear. It depends on whether the reverse power is transmitted to the transmission gear or the shift gear and the second transmission gear are stopped.

[0004]

[Problems to be solved by the device]

 In the structure described above, the shift gear is engaged with the convex portion formed on the inner surface of the mission case to stop the shift gear, thereby setting the pivoting state. In this case, the mission case itself is a large member, and many projections such as bearings of other transmission shafts are formed on the inner surface of the mission case.Therefore, the projections for the shift gear are formed on the inner surface of the mission case. However, there is room for improvement when handling and processing the mission case and forming and processing the protrusions. Further, in the shift gear, as shown in FIG. 1 of the publication, a meshing portion between a gear for super-spinning (11 in FIG. 1 of the publication) and a projection on the inner surface of the mission case is formed. Since two occlusal parts must be formed, there is room for improvement in terms of the shape of the shift gear itself and simplification of processing. The present invention is a shift gear for switching operation between the super turning state (slow turning state) and the turning state, and simplifies, forms and processes the structure of this shift gear stop structure (for turning state). The purpose is to simplify and simplify the shape of the shift gear itself.

[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. That is, the shift gear for transmitting the low-speed forward rotation power or reverse rotation power to the second transmission gear is slidably supported between the engagement position with the second transmission gear and the separated position away from the second transmission gear. The shift fork is provided with a shift fork for slidingly operating the shift gear, and the shift fork is provided with an engagement portion that engages with the second transmission gear at a separated position of the shift gear and stops and holds the second transmission gear.

[0006]

[Action]

 When configured as described above, for example, as shown in FIG. 2, if the shift gear 32 is slid rightward on the paper surface by the shift fork 39 and the shift gear 32 is engaged with the second transmission gear 30, the normal rotation power of low speed or The reverse rotation power is transmitted to the second transmission gear 30. Therefore, for example, if the left side gear 26 is operated to be separated from the first transmission gear 24 and interlocked with the second transmission gear 30, the low speed forward rotation power or reverse rotation power transmitted to the second transmission gear 30 is traveled to the left. Transmitted to the device, the aircraft makes a gentle turn to the left or a super turning turn. Next, when the shift fork 39 is operated to slide the shift gear 32 to the left on the opposite side of the drawing, the shift gear 32 is separated from the second transmission gear 30, and the engagement portion 39a of the shift fork 39 is moved to the second transmission as shown in FIG. The second transmission gear 30 is stopped and held by the shift fork 39 by engaging with the gear 30. As a result, for example, if the left side gear 26 is operated away from the first transmission gear 24 and linked with the second transmission gear 30, the left traveling device is stopped and the aircraft turns leftward. ..

As described above, according to the present invention, the second transmission gear is stopped and held by the engaging portion of the shift fork for sliding the shift gear. Such a shift fork is sufficiently smaller and lighter than the mission case, and when forming and processing the above-mentioned occlusal part on the shift fork, the part that interferes with this work is the shift fork. Almost never. This makes it easier to handle smaller and lighter shift forks than to handle large and heavy mission cases, and to form the aforementioned occlusal portions on the shift forks rather than forming and processing convex parts on the inner surface of the mission case.・ Processing can be done more easily. In the conventional structure of the shift gear, as shown in FIG. 1 of the above publication, it was necessary to provide the shift gear with an engaging portion with the convex portion of the inner surface of the transmission case. However, in the present invention, this engaging portion serves as the shift fork. Since it is provided, it is not necessary to provide this occlusal part in the shift gear.

[0008]

As described above, by providing the shift fork of the shift gear with the engaging structure for stopping and holding the shift gear for turning and the second transmission gear, simplification of this stop structure and simplification of formation and processing are achieved. The structure is advantageous in terms of manufacturing cost. Also, by omitting the occlusal portion for the stop structure also in the shift gear, the shape and processing of the shift gear itself can be simplified, and the structure is more advantageous in terms of manufacturing cost.

[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 1 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 3 of the belt type continuously variable transmission 2 via the. The power from the output shaft 4 of the belt type continuously variable transmission 2 passes through the first gear 5, the second gear 6, the first transmission shaft 7, the third gear 8, the fourth gear 9 and the output pulley 10 and the mowing unit. It is transmitted to (not shown).

A forward gear 11 and a reverse gear 12 are fitted on the first transmission shaft 7 so as to be rotatable relative to each other, and a shift gear 13 is slid between the forward and reverse gears 11 and 12 in a spline structure. It is freely fitted. With this structure, when the shift gear 13 is engaged with the forward gear 11, the power of the first transmission shaft 7 is transmitted to the second transmission shaft 15 from the fifth gear 14 (meshed with the forward gear 11) in the forward state. .. When the shift gear 13 is engaged with the reverse gear 12, the reverse gear 12, the sixth gear pair 16 and the fifth gear 14 (the sixth gear pair 16 are engaged) with the power of the first transmission shaft 7 in the reverse state. It is transmitted to the second transmission shaft 15.

A first high speed gear 17 is externally fitted to the second transmission shaft 15 so as to be relatively rotatable, and a shift gear 18 is externally fitted to be slidable in a spline structure. A low speed gear 20, a medium speed gear 21, and a second high speed gear 22 are fixed to the third transmission shaft 19, and the first and second high speed gears 17 and 22 are meshed with each other. As a result, the shift gear 18 is slid to engage the first high speed gear 17, the medium speed gear 21, and the low speed gear 20 so that the power can be shifted into three stages of high, medium, and low. Is transmitted to the first transmission gear 24.

The right and left side gears 26 are relatively rotatably fitted over the support shaft 25 supporting the first transmission gear 24, and the input gear 28 of the left and right traveling devices 27 is constantly meshed with the left and right side gears 26. ing. As a result, the left and right side gears 26 are engaged with the first transmission gear 24 (corresponding to the interlocking connection position with the first transmission gear 24), so that the forward rotation power for straight traveling is applied to the left and right crawler type traveling devices 27. Communicate to. The spring 29 urges the side gear 26 toward the first transmission gear 24 side.

A pair of second transmission gears 30 are externally fitted to the left and right of the support shaft 25, and a multi-plate friction clutch 31 is provided between the second transmission gear 30 and the side gear 26. On the other hand, a pair of shift gears 32 (corresponding to shift gears, which is a feature of the present invention) are slidably fitted on both ends of the third transmission shaft 19 by a spline structure. The left and right shift gears 32 are located at an engagement position with the second transmission gear 30 as shown in FIG. 2 and at a separated position away from the second transmission gear 30 by sliding leftward from the state shown in FIG. It is configured so that it can be slid into two positions.

As shown in FIGS. 1 and 2, a pair of left and right shift forks 39 that are engaged with the boss portions of the left and right shift gears 32 and slide and operate the boss portions are arranged in the mission case 1. The pair of left and right shift forks 39 is fixed to one operation shaft 42, and has an engaging portion 39a capable of engaging with the second transmission gear 30 on the lower side. A switching lever 41 capable of sliding the operation shaft 42 is provided in the control portion of the machine body, and the switching lever 41 can slide the left and right shift forks 39 and the shift gear 32 in the same direction.

With the above structure, as shown in FIG. 2, when the switching lever 41 is operated to the gentle turning position and the left and right shift gears 32 are slid rightward on the paper surface, the left and right shift gears 32 are moved to the left and right second transmission gears 30. Bite into each of. As a result, the left and right second transmission gears 30 are rotated in the normal rotation state in which the dynamic force of the third transmission shaft 19 is lower than the straight traveling dynamic force transmitted to the first transmission gear 24 via the left and right shift gears 32. Be transmitted to. Therefore, for example, when the left side gear 26 is operated away from the first transmission gear 24 and the friction clutch 31 is pressed in and out by the pressing portion 43 of the left side gear 26 (corresponding to the interlocking connection position with the second transmission gear 30). ), The low-speed forward rotation power of the left second transmission gear 30 is transmitted to the left traveling device 27, and the aircraft slowly turns to the left due to the speed difference between the left and right traveling devices 27.

Next, when the switching lever 41 is operated to the pivotal turning position and the left and right shift forks 39 and the shift gear 32 are slid to the left side of the drawing, the left and right shift gears 32 are separated from the second transmission gear 30, and As shown in FIG. 1, the interlocking portions 39a of the left and right shift forks 39 engage with each of the second transmission gears 30, and the left and right second transmission gears 30 are stopped and held. As a result, for example, when the left side gear 26 is operated to be separated from the first transmission gear 24 and the friction clutch 31 is pressed and entered by the pressing portion 43 of the left side gear 26, the left traveling device 27 is braked and the machine body is left. It turns to the ground.

Next, the sliding operation structure of the left and right side gears 26 will be described. As shown in FIGS. 3 and 2, an operating arm 38 for sliding operation of the left and right side gears 26 and a hydraulic cylinder 33 (corresponding to operating means) for rocking the operating arm 38 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. ing. Then, when the hydraulic cylinder 33 extends until the side gear 26 separates from the first transmission gear 24 and moves to the neutral stop position where the friction clutch 31 is not pressed and operated, hydraulic oil is drained from the hydraulic cylinder 33 to remove the hydraulic cylinder. A drain oil passage 36 for stopping 33 at the neutral stop position is provided, and a variable relief valve 37 is provided in the drain oil passage 36.

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 26 mesh with the first transmission gear 24. If the operating lever 40 is operated to the left first turning position L 1 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 26 moves to the left side of the drawing. Slides away from the first transmission gear 24. 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 26 presses the friction clutch 31, and hydraulic oil escapes from the variable relief valve 37. The left side gear 26 stops at this neutral stop position. This is the state where the transmission to the left traveling device 27 is cut off, and the aircraft gently turns to the left.

When the operation lever 40 is operated to the second left turning position L2, the variable relief valve 37 is closed, the hydraulic cylinder 33 is extended from the neutral stop position, and the left friction clutch 31 is operated. To be done. In this case, as shown in FIG. 2, when the switching lever 41 is operated to the gentle turning position so that the left and right shift gears 32 are engaged with the second transmission gear 30, the left traveling device 27 rotates at a low speed in the forward direction. It can be driven to make a gentle turn. When the operating 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-described state, and the pressing force on the friction clutch 31 is weakened. As a result, the friction clutch 31 slips and the forward rotation speed of the left traveling device 27 can be changed.

On the contrary, if the switching lever 41 is operated to the pivotal turning position to engage the interlocking portions 39a of the left and right shift forks 39 with the second transmission gear 30 and stop and hold them, the operating lever When 40 is operated to the second turning position L2 on the left, the traveling device 27 on the left is restrained and the turning can be carried out. Further, when the operating lever 40 is positioned between the left first and second turning positions L1 and L2, the friction clutch 31 slips and the braking force on the left traveling device 27 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 embodiment of FIG. 2, the shift gear 32 is slid so that the low-speed forward rotation power is transmitted to the second transmission gear 30 (slow rotation state) and the second transmission gear 30 is stopped. Although it is configured to perform switching operation between two states, that is, a holding state (spot turning state), the shift gear 32 is configured to transmit the reverse rotation power instead of the normal rotation power at a low speed. It is possible to switch between two states: a state in which reverse rotation power is transmitted to 30 (a super-spinning state in which one traveling device 27 is driven in reverse) and a state in which the second transmission gear 30 is stopped and held (spinning state). You may comprise. In the embodiment of FIG. 2, the side gear 26 and the first transmission gear 24 have an interlocking structure, and the friction clutch 31 is provided between the side gear 26 and the second transmission gear 30. A friction clutch may be provided between the side gear 26 and the second transmission gear 30, and the side gear 26 and the second transmission gear 30 may have an occlusal structure, or both may have an occlusal structure, or both may have a friction clutch.

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 present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a side view near a shift fork, a shift gear, 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 side gears.

[Explanation of symbols]

 24 1st transmission gear 26 Side gear 27 Traveling device 30 2nd transmission gear 32 Shift gear 33 Operating means 39 Shift fork 39a Interlocking part of shift fork

Claims (1)

[Scope of utility model registration request] 1. A first transmission gear (24) in which forward rotation power for straight traveling is transmitted to each of a pair of left and right side gears (26) which transmits power to a pair of left and right traveling devices (27). ) And a second transmission gear (30) to which low-speed forward rotation power or reverse rotation power is transmitted, and each of the left and right side gears (26) is interlocked with the first transmission gear (24). A traveling power transmission structure for a work vehicle, comprising an operating means (33) independently slidable between a connection position and an interlocking connection position with the second transmission gear (30), comprising a low-speed forward rotation power. Alternatively, the reverse rotation power is applied to the second transmission gear (3
0), and a shift gear (32) for transmission to the second transmission gear (30) is supported so as to be slidable between an engagement position with the second transmission gear (30) and a separated position separated from the second transmission gear (30).
A shift fork (39) for slidingly operating the shift gear (32) is provided, and the shift gear (3) is provided.
A traveling power transmission structure for a work vehicle, wherein the shift fork (39) is provided with an engaging portion (39a) that engages with the second transmission gear (30) at the spaced position of 2) and stops and holds it.