JP7083277B2 - Work vehicle - Google Patents

Description

The present invention relates to a work vehicle such as a tractor.

Based on the operation of the hydrostatic continuously variable transmission (HST) that shifts the running power steplessly and the tranion shaft connected to the tranion shaft of the hydrostatic continuously variable transmission via the link mechanism. A work vehicle including a continuously variable transmission operation lever capable of continuously changing the traveling speed is known (see, for example, Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 10-35310 Japanese Patent No. 4826285

The link mechanism that connects the stepless speed change operation lever and the trunnion shaft of the hydrostatic continuously variable transmission device is usually arranged on the side surface of the mission case as shown in Patent Document 1, but depending on the model, the mission case Many members are arranged on the side surface of the link mechanism, and it may be difficult to secure an arrangement space for the link mechanism. In particular, when the mission case is also used in a work vehicle having a stepless speed change specification using a hydrostatic continuously variable transmission device and a work vehicle having a stepped speed change specification using a gear speed change mechanism, it becomes difficult to arrange the link mechanism. There was a problem.

The present invention has been created for the purpose of solving these problems in view of the above circumstances, and the invention of claim 1 is described above via a hydrostatic stepless speed changer and a link mechanism. A stepless speed change operation lever connected to the tranny shaft of the hydrostatic stepless speed change device, a first lever shaft which is a lever shaft of the uninterrupted speed change operation lever, and a second lever shaft which is a lever shaft of another operation lever. A work vehicle including a first lever shaft and a mission case for supporting the second lever shaft, wherein the link mechanism is rotatably supported by an intermediate portion of the second lever shaft. The base end portion of the second lever shaft including the link member is supported by the mission case, and the tip end portion of the second lever shaft is supported by the holding member fixed to the mission case side. It is a feature.
The invention according to claim 2 is the work vehicle according to claim 1, wherein the holding member has a holding portion for holding the tip end portion of the second lever shaft and the mission branching from the holding portion. It is characterized in that a plurality of fixing portions fixed to the case side are integrally provided.
The invention according to claim 3 is the work vehicle according to claim 2, wherein the fixed portion is also used as a regulating portion for regulating the rotation range of the intermediate link member.

According to the invention of claim 1, the link mechanism connecting the hydrostatic continuously variable transmission and the continuously variable transmission operating lever can rotate at the intermediate portion of the second lever shaft which is the lever shaft of the other operating lever. Since the intermediate link member supported by the lever is included, the hydrostatic continuously variable transmission and the continuously variable transmission operating lever can be connected via the second lever shaft, and the arrangement of the link mechanism becomes easy. Further, since the base end portion of the second lever shaft is supported by the mission case and the tip end portion of the second lever shaft is supported by the holding member fixed to the mission case side, the load acting from the link mechanism can be used. It is possible to prevent the second lever shaft from falling or loosening.
Further, according to the invention of claim 2, the holding member integrally includes a holding portion for holding the tip end portion of the second lever shaft and a plurality of fixing portions branched from the holding portion and fixed to the mission case side. As a result, the number of parts can be reduced and the cost can be reduced.
Further, according to the third aspect of the present invention, since the fixed portion is also used as the regulating portion that regulates the rotation range of the intermediate link member, the number of parts can be reduced and the cost can be reduced.

It is a left side view of the tractor which concerns on one Embodiment of this invention. It is a perspective view of the left side part of a mission case seen from the diagonally front left. It is a front sectional view of a main part of a mission case. It is a perspective view which looked at the link mechanism of a main shift lever diagonally from the front left. It is a perspective view which looked at the link mechanism of a main shift lever diagonally to the right rear. It is a main part perspective view which shows the mounting state of a holding member. It is the main part perspective view which showed the holding member by a virtual line. It is a main part perspective view which shows the mounting state (the levers and links are omitted) of a holding member. It is a perspective view of a holding member. (A) is a plan view of the holding member, (b) is a front view of the holding member, and (c) is a left side view of the holding member.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIGS. 1 to 3, 1 is a traveling machine of a tractor T, and the traveling machine 1 is attached to an engine mounting portion 2 on which an engine (not shown) is mounted and a front portion of a mission case 3. A hydrostatic continuously variable transmission 4 that shifts engine power steplessly, and a gear transmission 5 that is built in the mission case 3 and gradually shifts the power output from the hydrostatic continuously variable transmission 4. A front wheel 6 and a rear wheel 7 that are rotationally driven by the traveling power output from the gear transmission 5, a working machine connecting portion 8 that can connect various working machines (not shown), and a control unit 9 on which the operator rides. , Equipped with.

In the present embodiment, the hydrostatic continuously variable transmission 4 functions as a main transmission mechanism, and the gear transmission 5 functions at least as an auxiliary transmission mechanism and a low-speed transmission mechanism. As a result, the continuously variable transmission operation range of the main transmission mechanism is gradually switched based on the stepwise shift operation of the auxiliary transmission mechanism and the low speed transmission mechanism.

As shown in FIGS. 2 and 3, various speed change operation mechanisms are arranged around the left side surface portion of the mission case 3, and specifically, at least, a hydrostatic stepless speed change is provided via the link mechanism 10. The main speed change lever 11 (stepless speed change operation lever) connected to the tranion shaft (not shown) of the device 4, the lever shafts 12 and 13 (first lever shaft) of the main speed change lever 11, and the low speed speed change mechanism. A low-speed work lever 14 (another shift operation lever) for shifting gears and a lever shaft 15 (second lever shaft) of the low-speed work lever 14 are arranged.

As shown in FIG. 3, the base end side of the lever shaft 15 is rotatably supported by the side wall portion of the mission case 3, and the tip end side extends from the left side surface portion of the mission case 3 to the left outer side. The above-mentioned low-speed work lever 14 is integrally rotatably attached to the intermediate portion on the tip end side of the lever shaft 15, and the lever shaft 15 rotates according to the vertical operation of the low-speed work lever 14. A shifter 16 is integrally rotatably attached to the base end of the lever shaft 15 located inside the mission case 3, and when the lever shaft 15 rotates in response to the operation of the low-speed work lever 14, low-speed shifting is performed. The speed change gear (not shown) of the mechanism moves in the front-rear direction, and the speed change operation of the low-speed speed change mechanism is performed.

As shown in FIGS. 4 and 5, the main shift lever 11 can be operated in the left-right direction with the lever shaft 12 as the fulcrum and the operation in the front-rear direction with the lever shaft 13 as the fulcrum. The hydrostatic continuously variable transmission 4 is operated for shifting based on the operation of 11 in the front-rear direction.

The link mechanism 10 can rotate integrally with the lever-side link arm 17 that rotates around the lever shaft 13 as a fulcrum in response to the operation of the main speed change lever 11 in the front-rear direction and the trunnion shaft of the hydrostatic stepless speed change device 4. An intermediate link arm 19 (intermediate link member) rotatably supported between the trunnion side link arm 18 to be connected and the tip end side intermediate portion (tip side of the low speed work lever 14) of the lever shaft 15 of the low speed work lever 14. A first link rod 20 that connects the lever-side link arm 17 and the first arm portion 19a of the intermediate link arm 19, and a second arm portion 19b that connects the trunnion-side link arm 18 and the intermediate link arm 19. A two-link rod 21 is provided.

When the main shift lever 11 is operated in the front-rear direction, the hydrostatic continuously variable transmission 4 via the lever-side link arm 17, the first link rod 20, the intermediate link arm 19, the second link rod 21, and the trunnion-side link arm 18. The trunnion shaft rotates, and the engine power is continuously changed.

According to such a link mechanism 10, since the intermediate link arm 19 rotatably supported by the lever shaft 15 of the low-speed work lever 14 is included, the hydrostatic continuously variable transmission is performed via the lever shaft 15 of the low-speed work lever 14. The device 4 and the main speed change lever 11 can be connected to each other, and the link mechanism 10 can be easily arranged around the left side surface portion of the mission case 3 in which many members are arranged.

By the way, when the intermediate link arm 19 of the link mechanism 10 is supported by the lever shaft 15 of the low speed work lever 14, the operating load of the main shift lever 11 acts on the lever shaft 15 of the low speed work lever 14. The lever shaft 15 of the low-speed work lever 14 is rotatably supported by the side wall of the mission case 3 at the base end side, but is cantilevered at the tip end side, so that the load acting from the link mechanism 10 is applied. The lever shaft 15 of the low-speed work lever 14 may fall or play.

In order to solve such a problem, the tractor T according to the embodiment of the present invention is provided with a holding member 22 that supports the tip end portion of the lever shaft 15. As shown in FIGS. 6 to 10, the holding member 22 of the present embodiment has a holding portion 22a that holds the tip end portion of the lever shaft 15, and a plurality of holding portions 22a that are branched from the holding portion 22a and fixed to the mission case 3 side. The fixing portions 22b and 22c are integrally provided. According to such a holding member 22, since a metal plate material can be used and manufactured by punching or bending by a press, the number of parts can be reduced and the cost can be reduced.

Specifically, the holding portion 22a has a fitting hole 22d that fits into the tip of the lever shaft 15, and the fitting hole 22d rotatably supports the tip of the lever shaft 15. It regulates the fall and backlash of the lever shaft 15.

The fixing portions 22b and 22c are bent and formed at the extending portions 22e and 22f extending from the holding portion 22a to the mission case 3 side and the tip portions of the extending portions 22e and 22f, and are formed on the transmission case 3 side via the bolt B. 22g, 22h, and a fixed piece to be fastened to the above. Further, of the fixing portions 22b and 22c, the extending portion 22e of one of the fixing portions 22b is also used as a member for restricting the rotation range of the intermediate link arm 19 (first arm portion 19a). That is, when the first arm portion 19a of the intermediate link arm 19 tries to rotate backward beyond a predetermined rotation range, the first arm portion 19a comes into contact with the extending portion 22e of the fixing portion 22b, and the first arm portion 19a abuts on the extending portion 22e. The above rotation is restricted.

According to the present embodiment configured as described above, the hydrostatic stepless speed changer 4 and the main speed change lever 11 connected to the tranny shaft of the hydrostatic stepless speed changer 4 via the link mechanism 10 A tractor T including a lever shaft 13 of a main shift lever 11, a lever shaft 15 of a low-speed work lever 14, and a mission case 3 that supports the lever shaft 13 and the lever shaft 15, and the link mechanism 10 is a lever shaft. Since the intermediate link arm 19 rotatably supported by the intermediate portion of 15 is included, it is possible to connect the hydrostatic stepless speed change device 4 and the main speed change lever 11 via the lever shaft 15 of the low speed work lever 14. Therefore, the arrangement of the link mechanism 10 becomes easy.

Further, since the base end portion of the lever shaft 15 is supported by the mission case 3, and the tip end portion of the lever shaft 15 is supported by the holding member 22 fixed to the mission case 3 side, it acts from the link mechanism 10. It is possible to prevent the lever shaft 15 from falling or rattling due to a load.

Further, since the holding member 22 integrally includes a holding portion 22a that holds the tip end portion of the lever shaft 15, and a plurality of fixing portions 22b and 22c that branch from the holding portion 22a and are fixed to the transmission case 3 side. , The number of parts can be reduced and the cost can be reduced.

Further, since the fixing portion 22b is also used as a member for regulating the rotation range of the intermediate link arm 19, the number of parts can be further reduced and the cost can be further reduced.

The present invention is not limited to the above embodiment, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. For example, in the above embodiment, the intermediate link arm 19 (intermediate link member) of the link mechanism 10 is rotatably supported by the lever shaft 15 of the low speed work lever 14, but the levers of the operation levers other than the low speed work lever 14 are supported. The intermediate link arm 19 may be rotatably supported by a shaft. For example, an intermediate link arm using the lever shaft of a 2WD / 4WD switching operation lever (operation lever for switching between a two-wheel drive state and a four-wheel drive state) arranged in the vicinity of the lever shaft 15 of the low-speed work lever 14. 19 may be rotatably supported, and the tip of the lever shaft of the 2WD / 4WD switching operation lever may be supported by the holding member 22.

T tractor 1 Traveling machine 3 Mission case 4 Hydrostatic continuously variable transmission 5 Gear transmission 10 Link mechanism 11 Main speed change lever 13 Lever shaft 14 Low speed work lever 15 Lever shaft 19 Intermediate link arm 22 Holding member 22a Holding part 22b Fixed part 22c Fixed part

Claims (3)

With hydrostatic continuously variable transmission,
A continuously variable transmission operating lever connected to the trunnion shaft of the hydrostatic continuously variable transmission via a link mechanism,
The first lever shaft, which is the lever shaft of the unauthorized speed change operation lever,
The second lever shaft, which is the lever shaft of the other operating lever,
A work vehicle including the first lever shaft and a mission case for supporting the second lever shaft.
The link mechanism includes an intermediate link member rotatably supported by an intermediate portion of the second lever shaft.
The base end portion of the second lever shaft is supported by the mission case.
A work vehicle characterized in that the tip end portion of the second lever shaft is supported by a holding member fixed to the mission case side. The holding member is
A holding portion that holds the tip of the second lever shaft, and a holding portion.
The work vehicle according to claim 1, further comprising a plurality of fixing portions that are branched from the holding portion and fixed to the mission case side. The work vehicle according to claim 2, wherein the fixing portion is also used as a regulating portion that regulates the rotation range of the intermediate link member.

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