JP6537437B2 - Work vehicle - Google Patents

Description

  The present invention relates to a work vehicle provided with a drive unit located at the front or rear of a vehicle body frame, a swingable opening / closing bonnet covering the drive unit, and an assist unit for assisting the opening operation of the hood.

  As the work vehicle as described above, for example, a U-shaped lower cover whose plane shape is opened rearward and a fixed support frame erected at the front of the vehicle body frame swing in the vertical direction around the front fulcrum A left and right center portion of a fulcrum fitting having a movably supported engine bonnet and a gas spring for assisting opening operation of the engine bonnet, the gas spring being attached to the inner surface of the front end portion of the engine bonnet; There is a tractor etc. constructed over the stay extended from the center part on either side (for example, refer to patent documents 1).

JP, 2006-290121, A (paragraph number 0017-0020, FIGS. 1-3, FIG. 5)

  In the above configuration, since the engine bonnet can be opened and closed around the fulcrum at the front of the vehicle body, for example, the motive power part relatively frequently performs maintenance on the front and rear center side of the vehicle body away from the fulcrum of the vehicle front When the maintenance target device such as a radiator or an air cleaner that needs to be performed is deployed, the upper part of the maintenance target device can be largely opened by the opening operation of the engine bonnet. As a result, maintenance of the maintenance target device is facilitated. Further, by providing the gas spring, the upward operation of the engine bonnet can be facilitated.

  However, since it is not possible to open both left and right side portions of the motive power part by the opening operation of the engine bonnet, there is room for improvement in further facilitating maintenance of the motive power part. In addition, since the gas spring is located at the left and right central portions of the work vehicle, the upper part of the motive power part and the upper part of the engine bonnet in the closed position or the front part of the motive power part and the front of the engine bonnet in the closed position In the meantime, it is necessary to secure a space for housing the gas spring while avoiding contact between the gas spring and the driving part. Therefore, there is a possibility that the vehicle body may be enlarged, such as the amount of bulging upward on the front side of the engine bonnet may increase, or the amount of bulging forward of the engine bonnet may increase.

  In other words, it is desirable to improve the maintainability of the driving unit in which the maintenance target device is disposed on the front-rear center side of the vehicle body without increasing the size of the vehicle body.

As means for solving the above problems, a work vehicle according to the present invention is:
The motor drive unit includes a drive unit positioned at the front or rear of the vehicle body frame, a swingable opening / closing bonnet covering the drive unit, and an assist unit assisting the opening operation of the hood.
The bonnet is located at one of the front and rear end portions of the vehicle body frame and covers the front and rear end portions of the drive unit, the left and right side covers covering the lateral side of the drive unit, and covers the upper portion of the drive unit. An integral type in which the upper cover and the upper cover are integrally connected, and swings open and closed with a left-right oriented support shaft located at one end of the front and rear of the vehicle body frame;
The vehicle body frame includes a first linkage portion at which the assist unit is linked at a lateral end of the vehicle body frame.
The bonnet is provided with a second link portion in which the assist unit is linked at a lateral end portion of a lower end portion of the bonnet located closer to the end cover than the first link portion.
The assist unit includes a telescopic mechanism which is extended and biased, and is constructed across the first link portion and the second link portion on the lateral outside of the driving portion .
The assist unit includes a guide member positioned on a portion closer to the end cover than the first link portion in the vehicle body frame, and a link member extending from the guide member to the second link portion.
The linking member includes a fifth linking portion at a portion closer to the guide member than a fourth linking portion linked to the second linking portion,
The extension and contraction mechanism is bridged between the first link portion and the fifth link portion .

  According to this means, since the bonnet is an integral type in which the end cover, the left and right side covers, and the upper cover are integrally connected, the shape retention property of the bonnet can be enhanced. Then, at the open position of the bonnet, the upper part and the left and right lateral parts of the driving part can be largely opened, which facilitates maintenance of the driving part. In particular, if the maintenance target device such as a radiator or an air cleaner that requires relatively frequent maintenance is disposed on the front and rear center side of the vehicle body in the driving unit, for example, the upper portion and the left and right sides of the maintenance target device The side can be opened more widely, and maintenance of the maintenance target device can be further facilitated.

  In addition, the worker can easily open and close the heavy bonnet in which the end cover, the left and right side covers, and the upper cover integrally open and close by the action of the assist unit.

  Then, by positioning the assist unit laterally outside the drive unit, it is necessary to secure a space for housing the assist unit between the upper or front end of the drive unit and the upper end of the bonnet at the closed position. As a result, it is possible to avoid the upsizing of the vehicle body caused by securing of the storage space between them.

  In addition, the position of the assist unit in the state in which the bonnet is positioned at the open position can be positioned at a low position close to the lower end of the bonnet. This makes it less likely that the assist unit will interfere with the maintenance of the drive unit with the bonnet positioned at the open position.

As a result, the maintainability of the drive unit can be improved without increasing the size of the vehicle body, and in particular, the maintainability of the drive unit disposed on the front-rear center side of the vehicle body is improved. It can be done.
Furthermore, in the assist unit, in the closed position of the bonnet, the expansion and contraction mechanism contracts, and the contraction causes the third link portion of the link member to reach the end on the first link portion side in the guide portion, thereby the extension mechanism and The link member is in a state of being close to the vehicle body frame in the front-rear orientation.
Then, when the opening operation of the bonnet is performed in the assist unit, the extension mechanism is extended, and the extension member swings the link member in the rising direction with the third link portion as a fulcrum by the extension. Push the link upwards. Thereby, the assist unit can assist the opening operation of the hood.
Thereafter, the extension unit of the assist unit stops the extension of the extension mechanism, and the link member swings and stops in a predetermined inclined posture, thereby fixing and holding the bonnet in a predetermined open position.
At this time, the linking member is inclined at a relatively large angle on the front and rear end sides of the vehicle body frame, and the extension mechanism is tilted at a smaller angle than the linking member on the front and rear center side of the vehicle body than the linking member. It will be in the state. As a result, for example, the inclination angle of the expansion and contraction mechanism when the bonnet is located at the open position is smaller than when the expansion and contraction mechanism is bridged over the first link portion and the second link portion. The position is lowered. Therefore, in the maintenance of the motive power unit in which the bonnet is positioned at the open position, the inconvenience that the assist unit interferes is further less likely to occur.

As one of the means to solve the problem more suitably,
The guide member may have Bei Ete a guide portion for guiding the third linkage portion located on one end of the linkage member in the longitudinal direction.

According to this means, in the assist unit, in the closed position of the bonnet, the expansion and contraction mechanism contracts, and the contraction causes the third link portion of the link member to reach the end portion on the first link portion side of the guide portion, thereby expanding and contracting. The mechanism and the linking member approach the vehicle body frame in the front-rear orientation.
Then, in the assist unit, when the bonnet opening operation is performed, the extension mechanism expands, and the extension causes the third link portion of the link member to move along the guide portion toward the end cover, and the link member The second link portion of the bonnet is pushed upward by swinging in the rising direction with the third link portion as a fulcrum. Thereby, the assist unit can assist the opening operation of the hood.
Thereafter, in the assist unit, the third link portion reaches the end on the end cover side of the guide portion, and the extension of the extension mechanism is stopped, and the link member swings and stops in a predetermined inclined posture, thereby specifying the bonnet. Hold fixed in open position of.
At this time, the linking member is inclined at a relatively large angle on the front and rear end sides of the vehicle body frame, and the extension mechanism is tilted at a smaller angle than the linking member on the front and rear center side of the vehicle body than the linking member. It will be in the state. As a result, for example, the inclination angle of the expansion and contraction mechanism when the bonnet is located at the open position is smaller than when the expansion and contraction mechanism is bridged over the first link portion and the second link portion. The position is lowered. Therefore, in the maintenance of the motive power unit in which the bonnet is positioned at the open position, the inconvenience that the assist unit interferes is further less likely to occur.
Moreover, a small thing can be employ | adopted as an expansion-contraction mechanism, and the cost which an expansion-contraction mechanism requires can be reduced.
As a result, it is possible to improve the maintainability of the drive unit while reducing the cost required for the expansion and contraction mechanism.

It is a left side view of a tractor. It is a top view of a tractor. It is a perspective view of the principal part which shows composition, such as a front guard and bonnet. It is a left view of an important section showing the state where the 2nd guard member of a front guard is located in a guard position, and a bonnet is located in a closed position. It is a left side view of the principal part which shows the state where the 2nd guard member of a front guard is located in a retreat position, and the bonnet is located in an open position. It is an exploded perspective view of an important section showing composition, such as an assistant unit. It is a disassembled perspective view of the principal part which shows the attachment structure of a headlight. It is a perspective view of the principal part which shows the composition about fixed holding of a bonnet, etc. It is a longitudinal cross-sectional back view of the principal part which shows the state before fixation holding of the bonnet by a lock mechanism. It is a longitudinal cross-sectional back view of the principal part which shows the fixed holding state of the bonnet by a locking mechanism, and a fixed release state. It is a disassembled perspective view of the principal part which shows the structure of a locking mechanism. It is a vertical rear view of the principal part which shows the state before fixation holding of the bonnet by the lock mechanism of another form. It is a longitudinal cross-sectional back view of the principal part which shows the fixation holding state and the fixation cancellation | release state of the bonnet by the locking mechanism of another form.

  Hereinafter, as an example of a mode for carrying out the present invention, an embodiment in which the present invention is applied to a tractor which is an example of a work vehicle will be described based on the drawings.

In addition, the direction which the arrow of the code | symbol F described in FIG. 1 points is the front side of a tractor, and the direction which the arrow of the code | symbol U points is the upper side of a tractor.
Further, the direction indicated by the arrow F in FIG. 2 is the front side of the tractor, and the direction indicated by the arrow L is the left side of the tractor.

  As shown in FIGS. 1 and 2, the tractor illustrated in the present embodiment includes a vehicle body frame 1 forming a framework of a vehicle body, a driving unit 2 disposed on the front side of the vehicle body frame 1, and a rear portion of the vehicle body frame 1. The transmission unit 3 connected, the boarding type driving unit 4 located at the upper rear of the vehicle body frame 1, the left and right front wheels 5 steerable and driven by the power from the driving unit 2, and the driving from the driving unit 2 Connected to the rear end of the vehicle body frame 1 and the front guard 8 made of steel plate located just in front of the bonnet 7 to protect the bonnet 7 And a mower 10 disposed on the lower abdomen between the left and right front wheels 5 and the left and right rear wheels 6, and the like.

  As shown in FIGS. 3 to 6, the vehicle body frame 1 has left and right side members 11 made of steel plates long in the front and back, front end members 12 made of steel plates across the front ends of the side members 11 left and right, and front and rear centers of the side members 11 left and right A center pillar 13 connected to the side, and left and right brackets 14 for bonnet connection connected to front ends of the left and right side members 11 are provided.

  As shown in FIG. 1, FIG. 4, FIG. 5 and FIG. 8, the prime mover 2 is positioned right in front of the water-cooled engine 15 and engine 15 supported anti-vibration at the front of the vehicle body frame 1. A muffler 16, a cooling fan 17 located immediately after the engine 15, a radiator 18 located immediately after the cooling fan 17, an air cleaner 19 located above the engine 15, and the like are provided.

  As shown in FIG. 1, FIG. 2, FIG. 4, FIG. 5, and FIG. 8, the upper side of the rear end of the drive unit 2 is covered by the upper panel 20, and the lower side of the rear end is covered by the under panel 21. There is. The under panel 21 is provided with an opening 21A for suction and a dustproof screen 21B covering the opening 21A.

  The driving unit 4 includes a steering wheel 22 for steering the front wheel, a display panel 23 for displaying an engine rotational speed and the like, a driver's seat 24 positioned above the transmission unit 3, and the like.

As shown in FIGS. 1 to 6, the bonnet 7 includes a front cover 25 which is an end cover that covers the front end of the drive unit 2, left and right side covers 26 made of sheet metal covering the lateral side of the drive unit 2, and a drive. The upper cover 27 made of sheet metal covering the upper part of the part 2 and the like are integrally connected, and open and close pivoting with the left and right first support shaft 28 located at the front end of the vehicle body frame 1 as a fulcrum .
Thereby, the shape retention property of the bonnet 7 can be improved. In addition, the bonnet 7 is of a post-opening type that largely releases the rear side of the driving portion 2 at the open position. As a result, maintenance of the radiator 18 and the like located on the rear side of the drive unit 2 is facilitated.

  As shown in FIGS. 1 and 3, the front cover 25 has a U-shaped first member 25 </ b> A in a plan view forming the lower end portion thereof, and an upper side of the front cover 25 functioning as an exhaust portion for discharging the cooling air , And the like. A dustproof screen is employed for the second member 25B. The left and right side covers 26 each include a dustproof screen 26A that functions as an exhaust unit for discharging the cooling air.

As shown in FIGS. 1 to 7, the bonnet 7 is provided with a bonnet frame 29 made of steel plate forming a framework of the bonnet 7, a headlight 30 having right and left light portions 30A and a frame portion 30B, and the like. .
The upper cover 27 is welded to the upper part 29A of the bonnet frame 29. The upper edges 26B of the side covers 26 are welded to the left and right lower edges 27A of the upper cover 27.
The bonnet frame 29 includes left and right first connecting portions 29B at the lower end portion of the front end portion. The left and right first connecting portions 29B are connected to the left and right brackets 14 of the vehicle body frame 1 via the left and right bolts 28 and the like that function as the left and right first support shafts 28.
The bonnet frame 29 is provided with a second connecting portion 29C at the left and right center portions of the front end portion thereof. The front cover 25 is connected to the lower side of the second connecting portion 29C, and the headlight 30 is connected to the upper end portion of the second connecting portion 29C. The left and right ends of the front cover 25 are connected to the front ends of the left and right side covers 26. The left and right end portions of the headlight 30 are connected to the left and right front end portions of the upper cover 27.
As a result, the bonnet 7 is integrally formed with the front cover 25, the left and right side covers 26, the upper cover 27, the bonnet frame 29 and the headlight 30, and is laterally positioned at the lower end portion of the front end of the bonnet 7. It is configured to swing open and close with the first support shaft 28 as a fulcrum.

As shown in FIG. 7, the headlight 30 is provided with a female screw portion 30 </ b> C coupled to the second connecting portion 29 </ b> C of the bonnet frame 29 at the left and right center portions of the frame portion 30 </ b> B. The bonnet frame 29 has a single through hole 29D for bolt insertion at the upper end of the second connecting portion 29C.
The headlight 30 is provided with connecting portions 30D connected to the left and right end portions of the upper cover 27 at the left and right end portions of the frame portion 30B. The left and right connecting portions 30D have upper and lower recesses 30E for bolt insertion which are recessed forward from their rear ends. The upper cover 27 is provided with two female screw portions 27B aligned vertically at the front end portions of the left and right end portions thereof.
Thus, the headlight 30 can be easily assembled to the upper cover 27 and the bonnet frame 29 with the five bolts 31.

As shown in FIG. 6, the left and right bolts 28 functioning as the first support shaft 28 have a large diameter portion 28A that is inserted through the through hole 29E of the first connection portion 29B on the bonnet side, and the bracket of the vehicle body frame 1 A stepped bolt including a small diameter male screw portion 28B to be inserted into the fourteen through holes 14A, and the like is employed.
Thereby, the clearance gap which arises between the volt | bolt 28 on either side and the 1st connection part 29B on either side can be made small. As a result, it is possible to suppress the occurrence of the problem that the front end of the bonnet 7 rattles in the radial direction of the bolt 28.

The ring shaped cushion rubbers 32 are externally fitted to the large diameter portions 28A of the left and right bolts 28. Each cushion rubber 32 is sandwiched between the flange portion 28C of the bolt 28 and the first connecting portion 29B on the bonnet side in a state where the vehicle body frame 1 and the bonnet 7 are connected by the left and right bolts 28 or the like.
As a result, it is possible to prevent the occurrence of the problem that the front end portion of the bonnet 7 rattles in the radial direction and the lateral direction of the bolt 28. Further, when the worker performs the opening and closing operation of the hood 7, the worker can be given a suitable sense of resistance, and as a result, the feeling of operation when opening and closing the hood 7 is improved.

As shown in FIGS. 4, 5 and 8 to 11, the bonnet 7 is fixed and held in the closed position by the lock mechanism 33. The lock mechanism 33 includes a rod 34 bent in an L shape, a hook member 35 that swings in the left-right direction, and a tension spring 36 that biases the hook member 35 back to the lock position.
The rod 34 is fixed to the left and right central portion of the upper portion of the rear end of the bonnet 7 in a state of having the hook portion 34A oriented in the front and rear direction. The hook member 35 is attached to the left and right central portions of the support member 38 fixed to the upper portion of the center pillar 13 by a front-to-back bolt 37 or the like serving as a rocking fulcrum. The hook member 35 is provided at the upper part thereof with a link portion 35A that enables a swing operation to the unlocked position by the hook portion 34A. The tension spring 36 is bridged from the right end of the support member 38 to the hook member 35.
The center pillar 13 has a recessed portion 13B at the upper left and right central portion thereof for permitting insertion and removal of the hooking portion 34A accompanying the swing operation of the bonnet 7. The upper panel 20 has a recessed portion 20A at the upper left and right central portion thereof for allowing passage of the hook portion 34A accompanying the swing operation of the bonnet 7.
The hook member 35 retracts toward the unlocking position against the action of the tension spring 36 by the hooking portion 34A coming into contact with the linking portion 35A in conjunction with the pivoting operation of the bonnet 7 to the closing position. Swing. The hook member 35 returns to the lock position by the action of the tension spring 36 in conjunction with the hook portion 34A moving downward of the link portion 35A with the arrival of the bonnet 7 at the closed position. Catch on hook portion 34A. Thereby, the lock mechanism 33 can fix and hold the bonnet 7 in the closed position.

As shown in FIGS. 1, 2, 4, 5 and 8 to 11, the lock mechanism 33 enables a swing operation of the hook member 35 against the action of the tension spring 36 to the unlocked position. An operating rod 39 is provided. The operation rod 39 is supported slidably in the left-right direction by a support portion 13A provided on the upper left portion of the center pillar 13. The right end 39A of the operation rod 39 is connected to the hook member 35, and the left end 39B protrudes upward from the opening 20B at the left end of the upper panel 20 and functions as an operation unit 39B for unlocking. A grip 40 made of resin is externally fitted to the operation portion 39B.
As described above, when the unlocking operation portion 39B is positioned at the left end portion of the upper panel 20, the operator positions the operation of the operation portion 39B from the operation portion 4 at the left and right center portions of the upper panel 20. This can be done quickly without being impeded by the steering wheel 22. As a result, the fixed holding of the bonnet 7 in the closed position by the lock mechanism 33 can be easily released by the operation of the operation unit 39B from the operation unit 4.

The bonnet 7 includes left and right compression springs 41 received and supported by the center pillar 13 via the upper panel 20. The left and right compression springs 41 push up the bonnet 7 upward from the closed position as the fixed holding of the bonnet 7 in the closed position by the lock mechanism 33 is released, and unlocking slightly above the closed position Hold in place. The left and right compression springs 41 allow the displacement of the bonnet 7 to the closed position by the downward swing operation of the bonnet 7 against the action.
Thus, the bonnet 7 is again moved by the lock mechanism 33 as the hook member 35 returns to the lock position after the release operation due to the bonnet 7 being in the closed position even after the release operation of the lock mechanism 33. It is possible to prevent the occurrence of the inconvenience of being fixed and held in the closed position. In addition, in the state where the bonnet 7 is fixed and held in the closed position, it is possible to prevent the occurrence of the inconvenience that the rear end portion of the bonnet 7 rattles.

  The configuration of the lock mechanism 33 can be variously changed, and a representative example thereof will be described below.

As shown in FIGS. 12 and 13, the lock mechanism 33 includes a rod 42 having a hook portion 42A directed in the front-rear direction, and a first swinging member 43 pivoted in the vertical direction with the bifurcated receiving portion 43A, A second swinging member 44 having a hook portion 44A and swinging in the left-right direction, a first tension spring 45 biasing the first swinging member 43 back to the upper unlocking position, and a second swinging member The second tension spring 46 is provided to bias the return 44 to the lock position.
The rod 42 is fixed to the upper left and right central portion of the rear end of the bonnet 7. The first swinging member 43 is attached to the left and right center side of the upper portion of the center pillar 13 by a front-to-back first bolt 47 or the like, which serves as a swing fulcrum. The first swinging member 43 is set in a swinging posture such that the receiving portion 43A is in the upper side open posture in the upper lock release position, and the receiving portion 43A is in the left side open posture in the lower lock position. The second rocking member 44 is attached to the left and right center side of the upper portion of the center pillar 13 by means of a second bolt 48 or the like directed forward and backward, which is a rocking support point. The second rocking member 44 includes, in the hook portion 44A, an interlocking portion 44B that enables a rocking operation to the left unlocking position by the first rocking member 43. The first tension spring 45 is bridged from the center pillar 13 to the first swinging member 43. The second tension spring 46 is bridged from the center pillar 13 to the second swinging member 44.
The first rocking member 43 is locked downward against the action of the first tension spring 45 by the receiving portion 43A receiving the hook portion 42A in conjunction with the rocking operation of the bonnet 7 to the closing position. Swing towards position. At this time, the receiving portion 43A guides the hook portion 42A to the lower lock position while changing the attitude from the upper open attitude at the lock release position to the left open attitude at the lock position. The second swinging member 44 resists the action of the second tension spring 46 by the receiving portion 43A coming into contact with the linking portion 44B in conjunction with the downward swinging movement of the first swinging member 43 to the lock position. Swing back to the left unlocking position. The second rocking member 44 moves to the right by the action of the second tension spring 46 in conjunction with the movement of the receiving portion 43A below the link portion 44B with the arrival of the bonnet 7 in the closed position. The hook portion 44A is hooked on the receiving portion 43A in the left open posture along with the return. Thus, the hooking portion 42A can be held at the lock position together with the first swinging member 43, and the bonnet 7 can be fixed and held at the closed position.

The lock mechanism 33 includes an operating rod 49 that enables the second swinging member 44 to swing to the unlocked position against the action of the second tension spring 46. The operation rod 49 is supported slidably in the left-right direction by a support portion 13A provided on the upper left portion of the center pillar 13. The right end 49A of the operation rod 49 is connected to the second swing member 44, and the left end 49B protrudes upward from the opening 20B at the left end of the upper panel 20 and functions as an operation unit 49B for unlocking. A grip 40 made of resin is externally fitted to the operation portion 49B.
As described above, when the unlocking operation unit 49B is positioned at the left end of the upper panel 20, the operator positions the operation of the operation unit 49B from the operation unit 4 at the left and right center of the upper panel 20. This can be done quickly without being impeded by the steering wheel 22. As a result, the fixed holding of the bonnet 7 at the closed position by the lock mechanism 33 can be easily released by the operation of the operation unit 49B from the operation unit 4.

As shown in FIGS. 1 and 3 to 6, the tractor includes an assist unit 50 that assists the opening operation of the hood 7. The assist unit 50 includes an expansion and contraction mechanism 51 that is biased to be extended, and the expansion operation of the expansion and contraction mechanism 51 assists the opening operation of the bonnet 7. The expansion and contraction mechanism 51 employs a gas spring 51 which is biased by an internal compressed gas. The vehicle body frame 1 is provided with a first link portion 1A to which the assist unit 50 is linked, at the left side member 11 of the left and right side members 11 located at the lateral end portion of the vehicle body frame 1. The bonnet 7 is provided with a second link 7A to which the assist unit 50 is linked at the left side end of the front lower end of the hood 7 located closer to the front cover than the first link 1A. The assist unit 50 is bridged over the first link portion 1A and the second link portion 7A on the left lateral outside of the driving portion 2.
Thereby, the shape retention property of the bonnet 7 can be improved. Then, at the open position of the bonnet 7, the upper part and the left and right lateral sides of the motive power unit 2 can be largely opened, and maintenance of the motive power unit 2 can be facilitated. In particular, maintenance of the radiator 18, the air cleaner 19 and the like located on the rear side of the drive unit 2 on the front-rear central side of the vehicle body in the drive unit 2 is facilitated.
In addition, the worker can easily open and close the heavy bonnet 7 in which the front cover 25, the left and right side covers 26, the upper cover 27 and the like are integrally opened and closed by the action of the assist unit 50.
And, by the assist unit 50 being located on the left lateral outside of the drive unit 2, a space for housing the assist unit 50 between the upper portion or the front portion of the drive unit 2 and the upper portion or the front portion of the bonnet 7 in the closed position. Because it is not necessary to secure the size of the vehicle body caused by securing the storage space among them can be avoided.
In addition, the position of the assist unit 50 in the state in which the bonnet 7 is positioned at the open position can be positioned at a low position near the front lower end portions of the left side member 11 and the bonnet 7. As a result, at the time of maintenance of the motive power unit 2 in which the bonnet 7 is positioned at the open position, it is less likely that the assist unit 50 interferes with the problem.
As a result, it is possible to improve the maintainability with respect to the drive unit 2, in particular, the maintainability with respect to the radiator 18 and the air cleaner 19 disposed at the rear of the drive unit 2, without increasing the size of the vehicle body.

The assist unit 50 includes a guide member 52 positioned on the front cover side of the vehicle body frame 1 on the front cover side of the first link portion 1A, a link member 53 extending from the guide member 52 to the second link portion 7A, and the like. . The guide member 52 includes a guide portion 52A for guiding the third link portion 53A located on one end side of the link member 53 in the front-rear direction. The linking member 53 includes a fifth linking portion 53C at a rear side portion closer to the guide member than the fourth linking portion 53B linked to the second linking portion 7A. The gas spring 51 is bridged over the first link portion 1A and the fifth link portion 53C.
As a result, in the assist unit 50, the gas spring 51 contracts at the closed position of the bonnet 7, and the contraction causes the third link portion 53A of the link member 53 to reach the rear end of the guide portion 52A. The link member 53 approaches the left side member 11 in the front-rear orientation along the left side member 11.
Then, in the assist unit 50, when the opening operation of the bonnet 7 is performed, the gas spring 51 extends, and the extension causes the third link portion 53A of the link member 53 to move forward along the guide portion 52A. The link member 53 swings in the rising direction with the third link portion 53A as a fulcrum, thereby pushing up the second link portion 7A of the bonnet 7 forward and upward. Thereby, the assist unit 50 can assist the opening operation of the hood 7.
Thereafter, in the assist unit 50, the third link portion 53A reaches the front end of the guide portion 52A, and the extension of the gas spring 51 is stopped, and the link member 53 swings and stops in a predetermined forward upward inclination posture. 7 is held fixed in a predetermined open position.
At this time, the linking member 53 is inclined upward at a relatively large angle at the front end of the vehicle body frame 1, and the gas spring 51 is inclined at a smaller angle than the linking member 53 on the rear side of the linking member 53. It will be in the state of being inclined upwards. Thus, for example, the front rising angle of the gas spring 51 when the bonnet 7 is located at the open position is smaller than when the gas spring 51 is installed across the first link portion 1A and the second link portion 7A. As a result, the position of the gas spring 51 becomes closer to the left side member 11. As a result, at the time of maintenance of the motive power unit 2 in which the hood 7 is positioned at the open position, the inconvenience of the assist unit 50 being in the way becomes less likely to occur.
Moreover, a small-sized gas spring 51 can be adopted, and the cost required for the gas spring 51 can be reduced.
As a result, it is possible to improve the maintainability of the driving unit 2 while reducing the cost required for the gas spring 51.

  In order to simplify the configuration of the assist unit 50, a rod is adopted as the linking member 53, and a long long hole is adopted in the guide portion 52A before and after one end of the rod is inserted.

  As shown in FIG. 6, the first link portion 1A has a first through hole 1B and a second through hole 1C at predetermined intervals in the front-rear direction as attachment holes for the assist unit. The front first through hole 1B is used as a mounting hole for the gas spring 51 when the specification of the tractor is a standard specification without a front loader (not shown). The rear second through hole 1C is used as a mounting hole for the gas spring 51 when the specification of the tractor is a loader specification equipped with a front loader (not shown). When the gas spring 51 is attached to the first link portion 1A using the first through hole 1B on the front side, the degree of opening of the bonnet 7 at the open position becomes large, and maintenance of the motive power portion 2 becomes easy to perform. When the gas spring 51 is attached to the first link portion 1A using the rear second through hole 1C, the degree of opening of the bonnet 7 at the open position becomes smaller, and the bonnet 7 comes into contact with the front loader It can be avoided.

As shown in FIG. 6, this tractor is provided with a guide mechanism 54 that guides the opening and closing operation of the bonnet 7. The guide mechanism 54 includes a guide member 55 and a linking member 56 which have the same configuration as the guide member 52 and the linking member 53 of the assist unit 50. The guide members 55 are disposed at symmetrical positions with the guide members 52 of the assist unit 50 in the vehicle body frame 1. The vehicle body frame 1 is provided with a guide member 55 on the right side member 11 of the left and right side members 11 located at the side end of the vehicle body frame 1. The bonnet 7 is provided with a sixth linking part 7 </ b> B in which the guide mechanism 54 is linked in a symmetrical position with the second linking part 7 </ b> A in the bonnet 7.
The guide member 55 includes a guide portion 55A for guiding the seventh link portion 56A located on one end side of the link member 56 in the front-rear direction. The linking member 56 includes an eighth linking portion 56B linked to the sixth linking portion 7B.
As a result, when the bonnet 7 is opened and closed, the left and right side portions of the bonnet 7 are guided open and closed by the assist unit 50 and the guide mechanism 54 in a well-balanced manner.

  In order to simplify the configuration of the guide mechanism 54, a rod is adopted as the linking member 56, and a long elongated hole before and after the end of the rod is inserted is adopted as the guide portion 55A.

As shown in FIGS. 1 to 5, the front guard 8 is positioned between the left and right first guard members 61 and the left and right first guard members 61 whose lower end portions 61A are fixedly connected to the vehicle body frame 1. A guard member 62 is provided. The left and right first guard members 61 have a left-right interval wider than the left-right width of the bonnet 7 to allow the bonnet 7 to enter between the left and right first guard members 61. The second guard member 62 is horizontally oriented at the front end of the vehicle body frame 1 between the guard position immediately before the bonnet 7 in the closed position and the retracted position allowing the bonnet 7 to swing to the open position. It swings back and forth with the second support shaft 63 as a fulcrum. The left and right first guard members 61 are located forward of the front end 62A of the second guard member 62, the front end 61B of which is located at the guard position.
Thus, when the operator performs maintenance on the prime mover 2 and the like covered with the hood 7, first, the second guard member 62 is swung from the guard position to the retracted position, and then the hood 7 is opened. By doing this, the hood 7 can be swung in the opening direction largely without being limited by the front guard 8. As a result, the periphery of the driving unit 2 covered by the bonnet 7 can be largely released, and maintenance of the driving unit 2 can be easily performed.
When the operator travels the tractor, the bonnet 7 is closed and the second guard member 62 is located at the guard position. Therefore, when the front guard 8 collides with another object, it is usually fixed to the vehicle body frame 1 The front end portions 61B of the connected first and second support members 61 having high support strength collide with other objects. As a result, it is possible to effectively prevent the occurrence of the inconvenience that the front guard 8 that has collided with another object contacts the bonnet 7.
Also, when the front guard 8 collides with another object, another object may get in between the left and right first guard members 61. In such a case, the second guard member 62 collides with the other object. And protect the bonnet 7.
As a result, protection of the hood 7 by the front guard 8 can be reliably performed without impairing the maintainability of the driving unit 2 and the like covered with the hood 7.

The front guard 8 is provided with a connecting member 64 having a horizontal width extending to the lower end portions of the left and right first guard members 61 and connecting the lower end portions of the left and right first guard members 61. The connecting member 64 is joined to the front surface of the front end member 12 forming the front end surface of the vehicle body frame 1.
As a result, the strength and shape retention of the lower end portion 61A of the left and right first guard members 61 can be enhanced. Further, the collision load when the front guard 8 collides with another object can be dispersed to the front end face of the vehicle body frame 1, and to the connection point between the lower end portion 61 A of the left and right first guard members 61 and the vehicle body frame 1. Stress concentration can be prevented.
As a result, it is possible to more reliably protect the bonnet 7 by the left and right first guard members 61 while improving the durability of the front guard 8.

As shown in FIGS. 2 and 3, the front guard 8 includes a connecting mechanism 65 that connects the second guard member 62 at the guard position to the first guard member 61 on the right side.
Thereby, the support strength in the guard position of the 2nd guard member 62 can be raised. As a result, when the front guard 8 collides with another object, if the other object gets in between the left and right first guard members 61, the second guard member 62 whose support strength is enhanced collides with the other object. Do.
As a result, it is possible to effectively prevent the occurrence of the inconvenience of the second guard member 62 coming into contact with the bonnet 7 due to backward movement or deformation due to a collision with another object. Protection of the bonnet 7 by the second guard member 62 Can be done more reliably.

The connection mechanism 65 urges the left and right connection pins 66 supported to the right of the free end of the second guard member 62 so as to be able to move in and out in the left and right directions. A spring 67 is provided. A through hole (not shown) for allowing insertion of the connection pin 66 is formed on the upper side of the right first guard member 61.
In the connection mechanism 65, when the second guard member 62 is located at the guard position, the right end portion of the connection pin 66 projects outward to the right of the second guard member 62 by the action of the compression spring 67, thereby the first guard member The second guard member 62 at the guard position is connected to the first guard member 61 on the right side by being inserted into the through hole 61.
In the connection mechanism 65, when the second guard member 62 is positioned at the guard position, the connection pin 66 is retracted to the left against the action of the compression spring 67, and the right end of the connection pin 66 is the first guard The connection between the second guard member 62 at the guard position and the first guard member 61 on the right side is released by being extracted from the through hole of the member 61.
That is, the connection mechanism 65 can be easily connected to the connection state in which the second guard member 62 in the guard position is connected to the first guard member 61 on the right side by the operation of the connection pin 66 and the release state in which the connection is released. It can be switched.

[Another embodiment]
The present invention is not limited to the configuration exemplified in the above embodiment, and will exemplify a representative alternative embodiment of the present invention.

[1] The work vehicle may be configured to include the motive power unit 2 and the bonnet 7 at the rear of the vehicle body frame 1.

[2] The work vehicle may not have the front guard 8.

[3] The configuration of the driving unit 2 can be variously changed. For example, the driving unit 2 may be configured to include an air-cooled engine 15 or may be configured to include an exhaust treatment device having a DPF (diesel particulate collection filter). The driving unit 2 may be a hybrid specification including an engine 15 and an electric motor.

[4] The connection configuration of the end cover 25, the left and right side covers 26, and the upper cover 27 in the bonnet 7 can be variously changed. For example, in the bonnet 7, the left and right side covers 26 and the upper cover 27 may be connected by bolt connection. Further, in the bonnet 7, the end cover 25 may be connected by welding to the left and right side covers 26 and the upper cover 27.

[5] The assist unit 50 may be disposed on the right lateral outside of the drive unit 2, or may be disposed on the left and right lateral outsides of the drive unit 2.

[6] The assist unit 50 may be configured such that the extension mechanism 51 is bridged over the first link portion 1A of the vehicle body frame 1 and the second link portion 7A of the bonnet 7.

[7] The first link portion 1A of the vehicle body frame 1 may have a single through hole 1B as a mounting hole for the assist unit, and three or more through holes may be separated by a predetermined distance in the front-rear direction. You may have it open.

[8] When the first link portion 1A of the vehicle body frame 1 has a single through hole 1B as a mounting hole for the assist unit, the second linking portion 7A of the bonnet 7 has a plurality of mounting holes for the assist unit The through holes may be provided at predetermined intervals.

[9] The expansion and contraction mechanism 51 may be, for example, a coil spring type in which a piston rod is fitted in a cylinder tube so as to be able to slide out, and the piston rod is biased by a coil spring in the cylinder tube.

[10] The guide member 52 may have, for example, a long groove in the front and back direction as the guide portion 52A.

[11] The link member 53 may be, for example, a steel strip provided with the third link portion 53A, the fourth link portion 53B, and the fifth link portion 53C.

[12] The linking member 53 includes, for example, a fourth linking portion 53B linked to the second linking portion 7A of the bonnet 7 at one end of the linking member 53, and the telescopic mechanism 51 at the other end of the linking member 53. May be configured to include a fifth linking portion 53C linked with the third linking portion 53A guided by the guide member 52 between the fourth linking portion 53B and the fifth linking portion 53C.

  The present invention comprises, for example, a tractor including a motive power unit positioned at the front or rear of a vehicle body frame, a swingable opening / closing bonnet covering the motive power unit, and an assist unit assisting the opening operation of the bonnet. The present invention can be applied to working vehicles such as mid-mount mowers, front moers, and front loaders.

Reference Signs List 1 vehicle body frame 1A first link portion 2 prime mover 7 bonnet 7A second link portion 25 end cover 26 side cover 27 upper cover 28 support shaft 50 assist unit 51 extension mechanism 52 guide member 52A guide portion 53 link member 53A third link portion 53B 4th linkage part 53C 5th linkage part

Claims (2)

The motor drive unit includes a drive unit positioned at the front or rear of the vehicle body frame, a swingable opening / closing bonnet covering the drive unit, and an assist unit assisting the opening operation of the hood.
The bonnet is located at one of the front and rear end portions of the vehicle body frame and covers the front and rear end portions of the drive unit, the left and right side covers covering the lateral side of the drive unit, and covers the upper portion of the drive unit. An integral type in which the upper cover and the upper cover are integrally connected, and swings open and closed with a left-right oriented support shaft located at one end of the front and rear of the vehicle body frame;
The vehicle body frame includes a first linkage portion at which the assist unit is linked at a lateral end of the vehicle body frame.
The bonnet is provided with a second link portion in which the assist unit is linked at a lateral end portion of a lower end portion of the bonnet located closer to the end cover than the first link portion.
The assist unit includes a telescopic mechanism which is extended and biased, and is constructed across the first link portion and the second link portion on the lateral outside of the driving portion .
The assist unit includes a guide member positioned on a portion closer to the end cover than the first link portion in the vehicle body frame, and a link member extending from the guide member to the second link portion.
The linking member includes a fifth linking portion at a portion closer to the guide member than a fourth linking portion linked to the second linking portion,
The extension and contraction mechanism is a working vehicle that is bridged between the first link portion and the fifth link portion . The guide member, the working vehicle according to the guide portion for guiding the third linkage portion located on one end of the linkage member in the longitudinal direction in claim 1 are Bei Ete.

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