JP2006307498A - Work vehicle and skid steering loader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a work vehicle enabling the easy maintenance of an engine 5 at the rear of a vehicle body. <P>SOLUTION: A skid steering loader 1 as the work vehicle comprises a lift arm 11 having a bucket 7 fitted to the tip thereof, a front link 22, a rear link 21, and a lift cylinder 23. Each of the front link 22, the rear link 21, and the lift cylinder 23 is connected, at its one end, to the lift arm 11 and connected, at its other end, to a frame 2 on the vehicle side. The height h of the connected position (position of a pin 31) of the rear link 21 to the frame 2 is set near half the height the height ha of the vehicle body. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a work vehicle that includes a work tool and a lift arm that can be raised and lowered, and that can raise and lower the work tool with a substantially vertical trajectory, and preferably relates to a configuration of a skid steer loader.

A skid steer loader is disclosed in, for example, Patent Document 1, and the skid steer loader in Patent Document 1 raises a bucket (corresponding to a work tool) at the tip of a boom (corresponding to a lift arm) substantially vertically. To get. The boom is connected to the main frame of the vehicle via a front control link, a rear boom support link, and a cylinder. Patent Documents 2 and 3 also disclose a skid steer loader or work vehicle having a similar basic configuration.
US Pat. No. 6,474,933 (FIG. 2, ABSTRACT, etc., main boom section 24A, bucket 40, control link 50, boom support link 28, cylinder 56, main frame 4) US Pat. No. 6,616,398 (Fig. 1) US Pat. No. 5,609,464 (FIG. 2)

  However, in the configuration of Patent Document 1, (A) the connection position of the boom support link to the main frame (the position indicated by reference numeral 32) is high, and thus a robust structure capable of supporting the weight of the boom, cargo handling object, etc. Must be formed vertically up to a considerable height on the vehicle body side, and a boom support link must be connected thereto. Therefore, it is difficult to secure a large opening for accessing the engine compartment (engine compartment 15) disposed at the rear of the vehicle from above, which makes engine maintenance work difficult.

  Further, in the configuration of Patent Document 1 described above, (B) when the boom is raised, the control link in the standing posture blocks the view of the side of the seat (FIG. 2 of Patent Document 1 or the like). See FIG. 3. On the other hand, when (C) the boom is lowered, this time, the boom itself obstructs the obliquely rear view with a wide area (see FIG. 1 of Patent Document 1). Accordingly, the field of view of the operator is narrowed, and there is room for improvement in terms of workability.

  In addition, also in the structure of the said patent documents 2 and 3, the subject of said (A) and (C) can be pointed out similarly.

  In general, work vehicles (especially skid steer loaders) are often used for work on narrow roads and the like, and there is a strong demand for compactness of the entire vehicle. On the other hand, from the viewpoint of operator comfort, there is also a request to secure a large space for the vehicle seat as much as possible, and a configuration capable of solving two contradictory requests is desired.

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  ◆ According to an aspect of the present invention, a work vehicle configured as follows is provided. A lift arm to which a work tool is attached at the tip, and a front link, a rear link, and a lift cylinder, each having one end connected to the lift arm and the other end connected to a vehicle-side frame. The height of the connection position of the rear link with respect to the frame is in the vicinity of a height of ½ of the vehicle body height.

  As a result, a strong structural member for supporting the weight of the lift arm, transport object, etc. via the rear link can be configured so as not to extend to a very high position. The maintenance workability of the engine or the like can be improved. Moreover, since the connection position of the rear link to the frame is low, it is easy to reduce the connection position of the rear link to the lift arm. Accordingly, a wide field of view of the operator obliquely behind can be secured in the lowered state of the lift arm.

  In the work vehicle described above, it is preferable that the rear link has a shape in which the upper side bends toward the front side of the vehicle with the vicinity of the connection portion with respect to the lift arm as a boundary.

  As a result, the rear link and the members attached thereto have a layout that does not obstruct the opening above the engine, and the maintenance workability of the engine or the like through the opening can be further improved.

  In the work vehicle, the position where the front link is connected to the frame is located between the front axle and the rear axle of the vehicle, and the position between the front axle and the rear axle is divided into two equal parts. It is preferable that it is located on the rear side.

  Thereby, even if the lift arm is raised and the front link is in a standing posture, the front link is unlikely to block the operator's side field of view, so that workability can be improved.

  In the work vehicle, the lift arm, the front link, the rear link, and the lift cylinder are arranged so as to overlap at least partially in plan view with respect to the front wheel and the rear wheel of the vehicle. Is preferred.

  This makes it possible to rationally arrange the front and rear wheels, the lift arm and its lifting structure in a compact space, so that the vehicle can be compact in the width direction that is easy to work even on narrow roads, etc. An operator's living space can be secured widely in the width direction.

  In the work vehicle described above, an engine is provided on the rear side of the work vehicle, a hinge is provided at a front end of a cover that covers the upper side of the engine, and the rear end of the cover is rotatable by the hinge. It is preferable.

  As a result, the cover can be opened and operated with a large rotation stroke, so that maintenance work for the engine and the like can be easily performed.

  In the work vehicle, the cover preferably includes at least a ceiling portion that covers an upper surface side of the storage space of the engine and a side wall portion that at least partially covers a side surface side of the storage space.

  As a result, when the cover is rotated and opened, the side surface of the engine storage space is particularly greatly exposed, so that access to the engine, particularly access from the side, is facilitated, and maintenance work for the engine and the like can be further performed. Easy to do.

  The above configuration can be applied to, for example, a skid steer loader.

  That is, the present invention is particularly suitable for a skid steer loader that is provided with a lift arm and is often used in a narrow road, and that requires good visibility of the operator.

  Next, embodiments of the invention will be described. FIG. 1 is an overall side view of a skid steer loader according to an embodiment of the present invention, FIG. 2 is a perspective view of the skid steer loader as seen from above, and FIG. FIG. 4 is a side view showing the second half of the cargo handling raising operation.

  1 and 2, a skid steer loader 1 as a work vehicle suspends a front wheel 3 and a rear wheel 4 on a frame-like frame 2, and a front wheel 3 and a rear wheel by an engine 5 provided in the frame 2. 4 can be driven. A cabin 6 that houses an operator's driver's seat is fixed at the front of the frame 2, and a counterweight (not shown) and the engine 5 are installed at the rear thereof.

  The skid steer loader 1 is provided with an opening 24 that opens the upper side and the upper side portion of the engine 5, and a cover 25 is installed to cover the opening 24. The front end of the cover 25 is pivotally supported on the vehicle body side by a hinge 26. In this configuration, when the rear end of the cover 25 is rotated upward and opened as shown by a chain line in FIG. 1, the engine 5 and its peripheral devices are moved upward and laterally through the opening 24 for maintenance work and the like. It is possible to access from.

  Particularly in the present embodiment, the cover 25 includes a rear wall 41 that covers the rear side of the storage space from the end of the ceiling 39 that covers the upper side of the engine 5 (the upper surface side of the storage space of the engine 5), and The side wall 40 that covers the side surface of the storage space is configured to extend downward. In other words, the cover 25 has a shape that covers part of the rear surface side and the side surface side of the storage space of the engine 5. Therefore, when the cover 25 is rotated upward, not only the upper surface side of the engine chamber but also the rear surface side upper part and the side surface side upper part are largely opened. As a result, access to the rear and side surfaces of the engine 5 is facilitated, and maintenance workability is greatly improved.

  The skid steer loader 1 includes a lift arm 11 that can be moved up and down. A bucket (working tool) 7 is rotatably provided at the tip of the lift arm 11 via a pin 38. In the present embodiment, as shown in FIG. 2, the lift arms 11 are provided in a pair of left and right sides with the cabin 6 interposed therebetween, and are configured as so-called double-arm type lift arms.

  The left and right lift arms 11 are arranged at positions immediately above the left and right wheels 3 and 4 (positions overlapping the left and right wheels 3 and 4 in the vehicle width direction). In the lowered state of the lift arm 11 shown in FIG. 1 and FIG. 2, the lift arm 11 extends slightly obliquely downward in the space immediately above the wheels 3, 4, and its tip almost follows the periphery of the front wheel 3. Is curved downward.

  A bucket cylinder (not shown) for rotating the bucket 7 is attached to the tip end side of the lift arm 11. The lift arm 11 can be raised and lowered by the configuration of the lifting device 10 described below. 1 and 2 show a state where the lift arm 11 is lowered to the lower limit position.

  The lower end of the rear link 21 is rotatably connected to the rear end portion of the frame 2 of the skid steer loader 1 via a pin 31. As shown in FIG. 2, the rear links 21 are arranged in a pair of left and right, their lower ends are pivoted to the left and right side surfaces of the frame 2, and the upper ends are connected to each other by a cross member 32. As shown in FIG. 1, the height h of the position of the pin 31 (that is, the connecting position of the rear link 21 to the frame 2) is slightly higher than ½ of the vehicle body height ha of the skid steer loader 1. Although it is small, it is about half the height of the vehicle body height ha.

  In the lowered state shown in FIG. 1 and FIG. 2, the rear link 21 is standing substantially vertically upward. The rear link 21 is an upper portion with a height portion as a boundary. Is bent in a direction approaching the vehicle front side, and has a shape in which the tip extends toward the front upper side. And the most proximal end part of the said lift arm 11 is connected with the bent part by the pin 33 so that rotation is possible.

  Further, the front ends of the front links 22 arranged in a pair of left and right are connected to the frame 2 through pins 34 so as to be rotatable. The pin 34 is disposed at a slightly lower height than the connecting pin 31 at the lower end portion of the rear link 21 and is located at the front and rear central portion of the frame 2. Speaking of the relationship between the front and rear axles 3a and 4a, the pin 34 is disposed at a position between the front axle 3a and the rear axle 4a. The pin 34 is connected to the front axle 3a and the rear axle 4a. It is located behind the intermediate position P. In other words, the pin 34 is located behind the bisection point P of the line segment connecting the front axle 3a and the rear axle 4a and ahead of the rear axle 4a. On the other hand, the rear end of the front link 22 is rotatably connected to the downward projecting portion 11 a in the vicinity of the base end portion of the lift arm 11 via a pin 35.

  In addition, the cylinder 2 side end of the lift cylinder 23 is rotatably connected to the rear end portion of the frame 2 and substantially the lowermost portion directly below the pin 31 via a pin 36. ing. On the other hand, the end of the lift cylinder 23 on the movable rod side is connected to the base end side portion of the lift arm 11 via a pin 37 so as to be rotatable.

  As shown in FIG. 2, the lift arm 11, the lift cylinder 23, the front link 22, the rear link 21, etc. are provided as a pair on the left and right sides of the vehicle body. The lift arm 11, the front link 22, the rear link 21, and the lift cylinder 23 are all arranged so as to overlap with the wheels (front and rear wheels 3 and 4) in the vehicle width direction.

  The lift cylinder 23 is a fluid pressure cylinder, specifically, a hydraulic cylinder, and is connected to a hydraulic supply means (not shown) (for example, an oil pump connected to the engine 5) via a control valve (not shown) such as an electromagnetic valve. Connected. This control valve is controlled to open and close by a control means (not shown), for example, a microcomputer type controller. In the present embodiment, the lifting device 10 of the lift arm 11 is configured to include at least a lift cylinder 23, a front link 22, and a rear link 21.

  Hereinafter, the operation at the time of lifting the cargo handling by the lifting device 10 will be described. 1 and 2 with the lift arm 11 lowered, the lift cylinder 23 is sufficiently retracted, the front link 22 is directed substantially horizontally toward the vehicle rear side as seen from the pin 34, and the rear link 21 is When viewed from the pin 31, it is slightly upward rearward.

  In this state, when an operator who sits on the driver's seat of the cabin 6 operates unillustrated cargo handling operation means (for example, a lever, a pedal, etc.), pressure oil is supplied to the lift cylinder 23 to expand, and the front link 22 is raised. The lift arm 11 is raised with the rotation in the direction.

  In the initial stage of the ascent (FIG. 3), the rear link 21 rotates around the pin 31 so as to fall backward as the lift arm 11 is raised. Therefore, the lift arm 11 moves the base side rearward, so that the bucket 7 at the tip is pulled rearward of the vehicle. As a result, the locus of the tip of the lift arm 11 in the first half when the cargo is lifted is a substantially linear locus although it slightly swells forward. The tip of the lift arm 11 has the maximum reach in the middle of the rise.

  After the lift cylinder 23 is further extended and the height of the tip of the lift arm 11 reaches about the intermediate height (about the height of the pin 33), the rear link 21 is centered on the pin 31 as shown in FIG. On the contrary, it rotates so as to fall forward. Therefore, since the base side of the lift arm 11 moves forward and upward, the lift arm 11 and the bucket 7 at the tip end thereof are lifted while being pushed forward slightly.

  Eventually, the lift arm 11 reaches the upper limit position shown by the solid line in FIG. At the upper limit position, the tip of the lift arm 11 achieves a large reach amount, although it is slightly shorter than the maximum reach in the above-described rising intermediate period. Further, at the upper limit position, the front link 22 is inclined slightly rearward from the vertical, and the height of the pin 35 at the upper end is slightly higher than the pin 33 connecting the lift arm 11 and the rear link 21. It has become.

  As described above, in the skid steer loader 1 of the present embodiment, the tip end of the lift arm 11 is pulled backward in the initial stage of cargo handling rise, and is pushed forward in the latter half stage. As a result, the trajectory of the tip end portion (pin 38) of the lift arm 11 to which the bucket 7 is attached draws a gentle curve close to a vertical straight line as indicated by a symbol T in FIG. The trajectory T rises while moving slightly forward from the lower limit position, then rises while moving backward by the aforementioned retracting action, and finally rises while moving forward by the aforementioned pushing action, It becomes an S-shaped curve. In addition, what is necessary is just to reverse the operation | movement at the time of cargo handling raising about the operation | movement at the time of cargo handling falling.

  With such a configuration, it is possible to increase the reach amount at the lifted position of the lift arm 11 and improve the handling efficiency as compared with the case where the lifting / lowering is performed by drawing a simple arc trajectory. The maximum load can be increased.

  As described above, in the skid steer loader 1 according to this embodiment, the height h of the connecting position of the rear link 21 with respect to the frame 2 (the position of the pin 31) is approximately ½ of the vehicle body height ha. It is comprised so that it may become. Accordingly, on the vehicle body side, a strong structural member for supporting the pin 31 can be structured so as not to extend to a very high position, so the opening 24 that opens the upper part of the engine room can be secured in a wide area, Maintenance workability of the engine 5 and its peripheral devices can be improved. Further, since the connection position of the rear link 21 to the frame 2 (position of the pin 31) is low, it is easy to reduce the connection position (pin 33) of the rear link 21 to the lift arm 11. Therefore, in the lift arm descending state shown in FIG. 1 and the like, a wide field of view behind the operator can be secured.

  Further, the rear link 21 is configured in such a shape that an upper portion is bent toward the front side of the vehicle with a vicinity of a connection portion (portion where the pin 33 is provided) to the lift arm 11 as a boundary. Therefore, a layout is realized in which the rear link 21 (or the cross member 32 connecting the pair of rear links 21) does not obstruct the opening 24, and the maintenance workability of the engine 5 and the like through the opening 24 is further improved. Can be improved.

  In the present embodiment, the connecting position of the front link 22 to the frame 2 (the position of the pin 34) is located between the front axle 3a and the rear axle 4a of the vehicle, and the front axle 3a and the rear axle 4a It is located behind the intermediate position (point P). Therefore, even if the lift arm 11 is raised as shown in FIG. 4 and the front link 22 is in a standing posture, the front link 22 does not interfere with the side view of the operator, so that workability can be improved.

  Further, in the skid steer loader 1 of the present embodiment, as shown in FIG. 2, the four members of the lift arm 11, the front link 22, the rear link 21, and the lift cylinder 23 are connected to the front wheel 3 and the rear wheel of the vehicle. 4 are arranged so as to overlap in a plan view. Therefore, for example, compared to the configuration shown in FIG. 6 of US Pat. No. 6,796,762, the front and rear wheels 3 and 4 and the lift arm 11 can be reasonably arranged inside a compact width, so that work can be performed even in narrow spaces. It is possible to make the vehicle body compact in the width direction that is easy to do, and at the same time, it is possible to secure a wide space (especially in the width direction) for the cabin 6 located between the lift arms 11 and the like.

  Further, in this embodiment, the engine 5 is provided on the rear side of the vehicle, and a hinge 26 is provided at the front end of the cover 25 that covers the upper side of the engine 5, and the rear end of the cover 25 is rotated by the hinge 26. It is supposed to be movable. Therefore, as shown in FIG. 1, a large rotation stroke of the cover 25 can be secured, so that maintenance work for the engine 5 and the like can be easily performed.

  In the present embodiment, the cover 25 includes a ceiling portion 39 that covers the upper surface side of the storage space (engine room) of the engine 5 and a side wall portion 40 that covers at least a part of the side surface of the storage space. ing. Therefore, when the cover 25 is rotated upward, the engine chamber is exposed not only on the upper surface side but also on the side surface side upper portion. In addition, as described above, the connection position of the rear link 21 with respect to the frame 2 is a low position in the vicinity of half the height of the vehicle body, so the lower end of the side wall portion 40 is positioned in the vicinity of the connection position. If this is done, it is possible to ensure a large exposed side surface area of the engine compartment when the cover 25 is opened. As a result, access to the side surface of the engine 5 becomes extremely easy, and the maintenance workability is remarkably improved.

  Although the preferred embodiment of the present invention has been described above, the above embodiment can be modified as follows, for example.

  (1) The work tool is not limited to the illustrated bucket 7, and for example, a fork or the like can be employed. The work tool may be detachably attached to the tip of the lift arm 11.

  (2) The lift arm 11, the front link 22, the rear link 21, and the lift cylinder 23 are arranged so as to overlap all of the front and rear wheels 3, 4. May be arranged.

  (3) The trajectory T at the tip of the lift arm 11 illustrated in FIG. 4 can be changed as appropriate according to circumstances such as the use of the work vehicle. In addition, it is said that the orientation and the arrangement position of the front link 22, the rear link 21, and the lift cylinder 23 shown in the above embodiment can be appropriately changed according to the locus of the tip of the lift arm 11 to be realized, the lift amount, and the like. Not too long. For example, by appropriately changing the layout of the front link 22, the rear link 21, etc., not only the substantially S-shaped trajectory illustrated in FIG. 4 but also a substantially C-shaped trajectory, for example, A curved trajectory can also be realized.

  (4) In the above embodiment, the tip of the lift arm 11 is configured to reach the maximum reach in the intermediate period of ascending. For example, the maximum reach is in the vicinity of the upper limit position (a position slightly below the upper limit position). Thus, the trajectory T may be changed as described above, and by doing so, the workability of the cargo handling work can be improved.

  (5) The method of connecting the front link 22, the rear link 21, and the lift cylinder 23 to the frame 2 and the lift arm 11 is not limited to the connection using pins. Further, the lift arm 11, the two links 21 and 22, and the lift arm 11 are not limited to a pair of left and right sides of the vehicle, and two or more pairs may be provided, for example.

  (6) The present invention is suitable for application to the skid steer loader 1 that is often used in narrow roads, but is not limited thereto, and the present invention is applied to all work vehicles including lift arms that can be lifted and lowered. It is possible to apply.

1 is an overall side view of a skid steer loader according to an embodiment of the present invention. The perspective view similarly seen from the upper side. The side view which shows the mode of the first half of the load raising operation | movement of a skid steer loader. The side view which shows the mode of the second half of cargo handling raising operation.

Explanation of symbols

1 Skid steer loader (work vehicle)
2 Frame 3 Front wheel 3a Front axle 4 Rear wheel 4a Rear axle 5 Engine 6 Cabin 7 Bucket (Working tool)
DESCRIPTION OF SYMBOLS 10 Lift arm lifting device 11 Lift arm 21 Rear link 22 Front link 23 Lift cylinder 24 Opening for engine maintenance 25 Cover 26 Hinge

Claims (7)

A lift arm with a work tool attached to the tip;
A front link, a rear link, and a lift cylinder each having one end connected to the lift arm and the other end connected to a vehicle-side frame;
A work vehicle, wherein a height of a connection position of the rear link with respect to the frame is in the vicinity of a half of a vehicle body height.   2. The work vehicle according to claim 1, wherein the rear link is configured in such a shape that an upper side bends toward the front side of the vehicle with a boundary near a connection portion with respect to the lift arm as a boundary.   The work vehicle according to claim 1 or 2, wherein a connection position of the front link to the frame is located between a front axle and a rear axle of the vehicle, and the front axle and the rear axle A work vehicle characterized in that the work vehicle is located on a rear side of a position that bisects the space between the two.   4. The work vehicle according to claim 1, wherein four members of the lift arm, the front link, the rear link, and the lift cylinder are connected to a front wheel and a rear wheel of the vehicle. A work vehicle arranged to overlap at least partially in a vehicle width direction.   The engine is provided on a rear side of the work vehicle, and a hinge is provided at a front end of a cover that covers an upper portion of the engine, and the rear end of the cover is rotatable by the hinge. The work vehicle according to any one of claims 1 to 4.   The work vehicle according to claim 5, wherein the cover includes at least a ceiling portion that covers an upper surface side of the storage space of the engine and a side wall portion that covers at least a part of a side surface side of the storage space.   The skid steer loader as a work vehicle as described in any one of Claim 1- Claim 6.

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