JP7061592B2 - Work machine - Google Patents

Description

The present invention relates to a work machine provided with an articulated work device including a boom and an arm, and more particularly to a work machine provided with a protective cover for an arm cylinder for driving the arm.

For cargo handling work such as loading an object onto a truck, a work machine configured by attaching an attachment having a gripping mechanism such as a grapple to a hydraulic excavator may be used (see Patent Document 1 and the like).

Japanese Unexamined Patent Publication No. 2012-127051

In hydraulic excavators used for excavation work, an arm cylinder is generally installed on the upper surface (back side surface) of the boom, and the work device is configured to operate in the arm cloud when the arm cylinder is extended. This is to make the cylinder extension operation with a strong output correspond to the arm cloud operation that is often used during excavation. However, in a work machine that requires a force to lift an object grasped by an attachment, that is, an arm dump operation, it is desirable to associate the cylinder extension operation with the arm dump operation. For that purpose, it is necessary to install a bracket connecting the base of the arm cylinder on the lower surface (ventral side surface) of the boom.

In this case, when cargo handling work is performed on a long object, for example, the long object may interfere with the arm cylinder when the attachment is turned, so it is desirable to protect the arm cylinder with a cylinder cover. However, if a long object frequently interferes with the cylinder cover or collides strongly, there is a concern that the cylinder cover itself may fall off. If an attempt is made to strengthen the fixed structure of the cylinder cover in order to prevent this falling off, the structure of the cylinder cover becomes complicated, the weight of the cylinder cover increases, and the cost increases.

An object of the present invention is to provide a work machine having a simple and lightweight structure for a cylinder cover that protects an arm cylinder and that can effectively prevent the cylinder cover from falling off.

In order to achieve the above object, the present invention includes a work machine main body, a work device attached to the work machine main body, and a boom in which the work device is rotatably connected to the work machine main body. It is configured to include an arm rotatably connected to the boom, an attachment attached to the arm, a boom cylinder for driving the boom, and an arm cylinder for driving the arm, and the arm cylinder is the boom. In the work machine arranged on the lower side, a first bracket provided on the lower surface of the boom, a second bracket provided on the lower surface of the boom, and a plurality of brackets surrounding the arm cylinder with respect to the first bracket. A cylinder cover attached with a bolt, a pin that penetrates the cylinder cover and the second bracket to the left and right, and an inner diameter of a pin hole of the second bracket and the cylinder cover through which the pin passes, and an outer diameter of the pin. Provided is a working machine characterized in that a gap is interposed between the two.

According to the present invention, the cylinder cover that protects the arm cylinder has a simple and lightweight structure, and the cylinder cover can be effectively prevented from falling off.

Side view showing the whole structure of the work machine which concerns on 1st Embodiment of this invention. Side view of the work equipment (front work machine) provided in the work machine shown in FIG. FIG. 2 is an enlarged view showing the arm cylinder and its peripheral portion in the work apparatus shown in FIG. The figure showing the part shown in FIG. 3 with the cylinder cover removed. Sectional view taken along the line VV in FIG. Enlarged view of the VI part in FIG. Phase diagram of the cylinder cover when the bolt is broken The figure which shows the state of the temporary support of an arm cylinder A diagram showing how a long object interferes with the cylinder cover. Sectional drawing of the cylinder cover provided in the work machine which concerns on 2nd Embodiment of this invention. Sectional drawing of the cylinder cover provided in the work machine which concerns on 3rd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment)
-Working machine-
FIG. 1 is a side view of the work machine according to the first embodiment of the present invention, and FIG. 2 is a side view of a work device (front work machine) provided in the work machine shown in FIG. In FIG. 2, equipment (driver's cab, etc.) other than the work equipment mounted on the swivel frame (described later) and the cylinder cover (described later) are not shown. Hereinafter, the direction (direction in FIG. 1) facing the operator sitting in the driver's seat is defined as the front of the swivel body 12. The work machine shown in FIG. 1 uses a hydraulic excavator as a base machine, and includes a work machine main body 10 and a work device 20 attached to the work machine main body 10. The work machine main body 10 includes a traveling body 11 and a swivel body 12.

The traveling body 11 forms the base structure of the work machine, and is a crawler type traveling body provided with left and right tracks 13. The left and right tracks 13 are driven by the left and right traveling drive devices 14, respectively. The traveling drive device 14 includes a hydraulic motor and a speed reducer. The swivel body 12 is provided on the traveling body 11 via a swivel wheel 15, and the swivel body 12 is provided with respect to the traveling body 11 about a shaft extending vertically by driving the swivel wheel 15 with a swivel motor (not shown). Turn. The swivel motor is a hydraulic motor, but in addition to the case where an electric motor is used, a hydraulic motor and an electric motor may be used in combination. In the present embodiment, a work machine provided with the traveling body 11 as the base structure is exemplified, but there is also a work machine having a post fixed to the ground as the base structure in a harbor or the like. There are also work machines whose base structure is a wheel-type traveling body. The present invention is also applicable to such work machines.

The swivel body 12 includes a swivel frame 16, a driver's cab 17, a machine room 18, a counterweight 19, and the like. The swivel frame 16 is a base frame of the swivel body 12 and supports each device mounted on the swivel body 12. The driver's cab 17 is located on one side (left side in this example) in the left-right direction in the front portion of the swivel frame 16. In the driver's cab 17, a driver's seat (not shown) on which the operator sits, an operating device operated by the operator, and the like are arranged. The machine room 18 is arranged behind the driver's cab 17 in the swivel frame 16. Although not particularly shown, the machine chamber 18 houses a prime mover which is an engine (internal engine), a hydraulic pump driven by the prime mover, a control valve for controlling hydraulic oil for driving a hydraulic actuator, heat exchangers, and the like. Has been done. An electric motor may be used as the prime mover. Further, tanks are arranged on the opposite side of the cab 17 with the working device 20 in the front portion of the swivel frame 16 interposed therebetween. The tanks include a fuel tank, a hydraulic oil tank and the like. The counterweight 19 is a weight that balances with the working device 20, and is supported by the rear end of the swivel frame 16.

-Working equipment-
The working device 20 is an articulated working machine, and includes a working arm 21 and an attachment 22. The working arm 21 includes a boom 23, an arm 24, a boom cylinder 25, an arm cylinder 26, and an attachment cylinder 27. In the present embodiment, the boom cylinder 25, the arm cylinder 26, and the attachment cylinder 27 are all arranged on the lower side of the working device 20 (for example, the lower side of the boom 23 and the arm 24 extended forward). The boom cylinder 25, the arm cylinder 26, and the attachment cylinder 27 are all hydraulic cylinders.

The boom 23 is rotatably connected to the front portion of the base frame (swivel frame 16) of the swivel body 12 via a foot pin P1 extending to the left and right. The lower surface of the boom 23 of the present embodiment (the ventral side surface facing downward when extended forward) is formed of a flat surface without bending or bending. The arm 24 is rotatably connected to the tip of the boom 23 via a pin P2 extending to the left and right.

The boom cylinder 25 has a base end connected to the work machine main body 10 (swivel frame 16 of the swivel body 12) via a pin P11 extending to the left and right, and is connected to the lower surface of the boom 23 via the pin P12 extending to the left and right. On the other hand, the tip is connected. The base end of the arm cylinder 26 is connected to the lower surface of the boom 23 via a pin P13 extending to the left and right, and the tip is connected to the lower surface of the arm 24 via a pin P14 extending to the left and right. The base end of the attachment cylinder 27 is connected to the lower surface of the arm 24 via a pin P15 extending to the left and right, and the tip is connected to the base end of the link 28 via a pin P16 extending to the left and right. An intermediate portion of the link 28 is connected to the tip of the arm 24 via a pin P3 extending to the left and right.

The attachment 22 is a grapple in this example, and is configured to include a gripping mechanism and a swivel mechanism for swiveling the gripping mechanism, and is suspended from the tip of the link 28 via a pin P17. In FIG. 1, a state in which a long object W (for example, wood) is gripped by an attachment 22 and lifted is illustrated in FIG. In addition, another work tool such as a bucket can be used for the attachment 22, and the grapple can be removed together with the link 28 and replaced with another work tool.

As described above, the boom cylinder 25, the arm cylinder 26, and the attachment cylinder 27 are arranged below the working device 20. Therefore, all of these cylinders drive the driven member (boom 23, arm 24, and attachment 22) in the direction of lifting the attachment 22 by the extension operation. That is, each cylinder is configured to exert a stronger driving force in the work of lifting an object gripped by a grapple.

-Cylinder cover-
FIG. 3 is an enlarged view of the arm cylinder and its peripheral portion, FIG. 4 is a view showing a state in which the cylinder cover is removed for the portion shown in FIG. 3, and FIG. 5 is a cross section taken along line VV in FIG. FIG. 6 is an enlarged view of the VI portion in FIG. In FIG. 5, the arm cylinder 26 is not shown. As shown in these figures, the lower part of the boom 23 is provided with a first bracket 31 (FIG. 4), a second bracket 32 (FIG. 4), a cylinder cover 33, and a pin 34.

The first bracket 31 is a flat bar-shaped member that supports the cylinder cover 33, and is fixed to the left and right of the lower surface 23a of the boom 23 by welding or the like. The left and right first brackets 31 extend back and forth along the lower surface 23a of the boom 23, and are provided with a plurality of (five in this example) bolt holes (screw holes) 31h at intervals in the front and back.

The second bracket 32 is a plate-shaped member having a pin hole 32h through which the pin 34 is passed, and is fixed to the left and right of the lower surface 23a of the boom 23 by welding or the like. The pin hole 32h is a stupid hole having a larger diameter than the bolt hole 31h. In the present embodiment, the first bracket 31 and the second bracket 32 are integrally formed, and the configuration in which the second bracket 32 forms a part of the first bracket 31 is exemplified, but the first bracket 31 and the second bracket are illustrated. 32 may be used as a separate member.

The cylinder cover 33 is a protective cover that protects the arm cylinder 26, and is provided corresponding to the tube 26a of the arm cylinder 26. The cylinder cover 33 includes a bottom cover 33a and left and right side covers 33b, and has a V-shape having a cross section orthogonal to the arm cylinder 26 with an opening facing the lower surface of the boom 23 (FIG. 5). ). A cylinder cover 33 surrounds the outer circumference of the tube 26a of the arm cylinder 26 together with the lower surface 23a of the boom 23.

The bottom cover 33a is a part of the cylinder cover 33 and faces the lower surface 23a of the boom 23 with the arm cylinder 26 interposed therebetween. In the present embodiment, the bottom cover 33a is formed in a gutter shape extending along the lower surface 23a of the boom 23, and has a V-shaped cross section orthogonal to the arm cylinder 26 (FIG. 5). The bottom cover 33a is inclined with respect to the lower surface 23a so as to move away from the lower surface 23a of the boom 23 as it approaches the tip of the boom 23 in order to allow the rotational movement of the arm cylinder 26 with the pin P13 as the fulcrum. (Fig. 3).

The left and right side covers 33b are portions that rise vertically from the left and right ends of the bottom cover 33a, and in the present embodiment, they are formed in a trapezoidal shape in a side view according to the inclination of the bottom cover 33a. The left and right side covers 33b can be formed by bending the left and right sides of the bottom cover 33a to the upper side (back side), but they may be formed of a member different from the bottom cover 33a and attached to the bottom cover 33a by welding or the like. A plurality of (five on one side in this example) through holes (not shown) are provided on the upper portions of the left and right side covers 33b (the portions facing the boom 23) corresponding to the bolt holes 31h of the first bracket 31. There is. The cylinder cover 33 is fixed to the lower surface 23a of the boom 23 by passing bolts 35 through these through holes from the outside in the left-right direction and screwing them into the bolt holes 31h of the first bracket 31. In the state of being fixed by these bolts 35, the upper edge of the cylinder cover 33 (the upper edge of the left and right side covers 33b, that is, the portion facing the lower surface 23a of the boom 23) is parallel to the lower surface 23a of the boom 23. In this state, the gap G1 is configured to be interposed between the upper edge of the cylinder cover 33 and the lower surface 23a of the boom 23 (FIGS. 3 and 6).

The pin 34 penetrates the cylinder cover 33 and the second bracket 32 to the left and right, and passes between the arm cylinder 26 and the lower surface 23a of the boom 23 to the left and right. In the present embodiment, one pin 34 penetrates the left and right side covers 33b and the left and right second brackets 32 of the cylinder cover 33, and retaining 36s are attached to both ends of the pin 34. As shown in FIG. 6, a gap G2 is interposed between the inner diameters of the pin holes 32h and 33h of the second bracket 32 and the cylinder cover 33 through which the pin 34 is passed and the outer diameter of the pin 34. The gap G2 is at least larger than the tolerance between the bolt 35 and the bolt hole 31h. When the cylinder cover 33 is fixed by the bolt 35, the weight of the cylinder cover 33 is not applied to the pin 34, and the pin 34 rattles with respect to the second bracket 32 and the cylinder cover 33.

At this time, the pins 34 are provided at only one place when viewed from the left and right (there is only one pin 34 in this embodiment), and the tip side of the boom 23 in the cylinder cover 33 (the most boom tip in this example). It is located between the two bolt holes 31h on the side). The center of gravity of the cylinder cover 33 is closer to the boom base end side than the pin 34, and in a state where it is not supported by the bolt 35, the cylinder cover 33 rotates with the pin 34 as a fulcrum, and the boom base end side of the cylinder cover 33 is moved. It is configured to be displaced downward (Fig. 7). Further, a shackle X on which a wire Y is hung can be attached to the pin hole 32h of the second bracket 32 (FIG. 8). The pin hole 32h is located near the tip of the tube 26a of the arm cylinder 26. Therefore, when the arm 24 is removed and the tip of the arm cylinder 26 becomes free during disassembly and assembly of the work device 20, the tip of the tube 26a of the arm cylinder 26 is hung on the pin hole 32h with the shackle X or the wire Y. It can be used when suspending and supporting the vicinity.

-effect-
(1) In the present embodiment, since the arm cylinder 26 is arranged under the working device 20, there is an advantage that the object gripped by the attachment 22 can be lifted by the extension operation of the cylinder having a large driving force. On the other hand, when the long object W is gripped and lifted, if the arm cloud operation is performed or the attachment 22 is swiveled, the long object W may interfere with the arm cylinder 26 as shown in FIG. In this regard, the arm cylinder 26 can be protected from collision with the long object W by surrounding the arm cylinder 26 with the cylinder cover 33.

However, when the long object W collides with the cylinder cover 33, an impact load is applied to the bolt 35 fixing the cylinder cover 33, and in the severe case, the bolt 35 may break and the cylinder cover 33 may fall off.

Therefore, in the present embodiment, as described above, between the inner peripheral surface of the pin hole 32h of the second bracket 32 and the pin hole 33h of the cylinder cover 33 and the outer peripheral surface of the pin 34 passed through these pin holes 32h and 33h. A gap G2 is interposed. That is, in a state where the bolt 35 supports the cylinder cover 33 soundly, the cylinder cover 33 and the pin 34 are not restrained from each other, and even if an impact that causes the bolt 35 to break acts on the cylinder cover 33, the pin 34 does not break. As a result, even if the support by the bolt 35 is lost, the pin 34 functions as a mechanical fuse, and the cylinder cover 33 is supported by the second bracket 32 via the pin 34. In the structure in which the arm cylinder 26 is protected by the cylinder cover 33, the cylinder cover 33 can be effectively suppressed from falling off with a simple structure mainly by adding a pin 34 as a mechanical fuse. Further, since only the pin 34 is mainly added, the structure of the cylinder cover 33 can be suppressed from becoming complicated and heavy.

(2) A gap G1 is interposed between the upper edge of the cylinder cover 33 and the lower surface 23a of the boom 23, and the upper edge of the cylinder cover 33 and the boom are in a state where the cylinder cover 33 is soundly supported by the bolt 35. The lower surface 23a of the 23 is substantially parallel to the lower surface 23a. Further, the pin 34 is provided at only one position on the cylinder cover 33 on the boom tip side when viewed from the left and right. As a result, when the support by the bolt 35 is lost, the pin 34 serves as a rotation axis and the cylinder cover 33 rotates. At this time, since the position of the pin 34 is on the boom tip side of the cylinder cover 33, the cylinder cover 33 is displaced to a posture in which the boom base end side is lowered. The positions of the work device 20 and the driver's cab 17 are displaced to the left and right, and the cylinder cover 33 can be visually recognized from the driver's seat 17, but the change in the state of the cylinder cover 33 in which the boom base end side is lowered when viewed from the cab 17 is big. That is, by devising the number and position of the pins 34, it is possible to promptly notify the operator of the cab 17 of the breakage of the bolt 35 by clearly changing the state of the cylinder cover 33.

Further, since the pin hole 32h of the second bracket 32 is located near the tip of the tube 26a of the arm cylinder 26, the tip of the arm cylinder 26 in a state where only the base end is connected at the time of disassembling and assembling the working device 20 or at the time of forwarding. It can be suitably used for temporary support of the cylinder.

(3) Since the first bracket 31 and the second bracket 32 are integrally configured, the support structure of the cylinder cover 33 can be further simplified. Further, even when the first bracket 31 and the second bracket 32 are attached to the lower surface 23a of the boom 23 by welding, the attachment is easy because both brackets are integrated, and the welding line is simple, so that a stable welding bead can be obtained. Can be formed. As a result, high mounting strength of the first bracket 31 and the second bracket 32 can be ensured.

(4) Since the pin 34 passes between the arm cylinder 26 and the boom 23, even if the second bracket 32 or the like is damaged and the pin 34 falls off from the second bracket 32, the pin 34 remains. It can be hooked on the arm cylinder 26 to prevent the cylinder cover 33 from falling off.

(Second Embodiment)
FIG. 10 is a cross-sectional view of a cylinder cover provided in the work machine according to the second embodiment of the present invention, and is a diagram corresponding to FIG. 5 of the first embodiment. The difference between this embodiment and the first embodiment is that the pin, which is a mechanical fuse for preventing the cylinder cover 33 from falling off, is divided into left and right. Specifically, the left and right pins 34L and 34R are used as elements corresponding to the pins 34 in the first embodiment. The configurations of the pins 34L and 34R can be changed as appropriate, but in the present embodiment, short pins having a collar only at one end are used as the pins 34L and 34R.

The left pin 34L is inserted into the left side cover 33b and the second bracket 32 of the cylinder cover 33 from the outside (left side) in the left-right direction, and the retaining 36 is provided at the tip protruding into the inner space of the cylinder cover 33. It is installed. The pin 34R on the right side is inserted into the side cover 33b and the second bracket 32 on the right side from the outside (right side) in the left-right direction, and the retaining 36 is attached to the tip portion protruding into the inner space of the cylinder cover 33. .. There is a sufficient distance between the left and right pins 34L and 34R.

Although two pins 34L and 34R are used in this embodiment, the central axes of the pins 34L and 34R are on the same straight line, and the arrangement is the same as that of the pin 34 of the first embodiment. Further, there is no pin as a mechanical fuse other than the pins 34L and 34R. Therefore, when the support by the bolt 35 is lost, the cylinder cover 33 rotates around the pins 34L and 34R as in the first embodiment.

The present embodiment is the same as the first embodiment with respect to other configurations.

The effects (1)-(3) of the first embodiment can also be obtained by this embodiment. In addition, in the present embodiment, since there is a sufficient distance between the left and right pins 34L and 34R, the arm cylinder 26 can be received between the pins 34L and 34R. Therefore, even if the arm cylinder 26 is designed to approach the lower surface 23a of the boom 23 during the arm dump operation, the pins 34L and 34R do not hinder the movement of the arm cylinder 26, and the degree of freedom in designing the working device 20 is increased. ..

(Third Embodiment)
FIG. 11 is a cross-sectional view of a cylinder cover provided in the work machine according to the third embodiment of the present invention, and is a diagram corresponding to FIG. 5 of the first embodiment. The difference between the present embodiment and the first embodiment is that, as in the second embodiment, the pin, which is a mechanical fuse for preventing the cylinder cover 33 from falling off, is divided into left and right. Specifically, the left and right pins 34l and 34r are used as elements corresponding to the pins 34 in the first embodiment. In this embodiment, bolts with heads are used as pins 34l and 34r.

Similar to the second embodiment, the left pin 34l is inserted into the left side cover 33b and the second bracket 32 from the outside (left side) in the left-right direction, and is pulled out to the tip portion protruding into the inner space of the cylinder cover 33. A double nut 37 is attached as a stopper. The pin 34r on the right side is inserted into the side cover 33b and the second bracket 32 on the right side from the outside (right side) in the left-right direction, and a double nut 37 is attached to the tip portion protruding into the inner space of the cylinder cover 33. .. There is a sufficient distance between the left and right pins 34l and 34r.

Also in this embodiment, the central axes of the pins 34l and 34r are on the same straight line, and the arrangement is the same as that of the pin 34 of the first embodiment. Further, there is no pin as a mechanical fuse other than the pins 34l and 34r. In addition, the distance between the double nut 37 and the head of the pin 34l or 34r is slightly larger than the thickness of the side cover 33b and the second bracket 32. Therefore, when the support by the bolt 35 is lost, the cylinder cover 33 rotates around the pins 34l and 34r as in the first embodiment.

The present embodiment is the same as the first embodiment with respect to other configurations.

The same effect as that of the second embodiment can be obtained by this embodiment as well. In addition, the present embodiment has an advantage that a mechanical fuse can be easily and inexpensively configured by using standard products such as bolts and nuts.

10 ... Working machine body, 20 ... Working equipment, 22 ... Attachment, 23 ... Boom, 23a ... Boom bottom surface, 24 ... Arm, 25 ... Boom cylinder, 26 ... Arm cylinder, 31 ... First bracket, 32 ... Second bracket , 33 ... Cylinder cover, 34, 34l, 34r, 34L, 34R ... Pin, 35 ... Bolt, G1, G2 ... Gap

Claims (5)

A boom having a work machine main body and a work device attached to the work machine main body, and the work device rotatably connected to the work machine main body, an arm rotatably connected to the boom, and the above-mentioned In a work machine in which an attachment attached to an arm, a boom cylinder for driving the boom, and an arm cylinder for driving the arm are included, and the arm cylinder is arranged under the boom.
The first bracket provided on the lower surface of the boom and
The second bracket provided on the lower surface of the boom and
A cylinder cover that surrounds the arm cylinder and is attached to the first bracket with a plurality of bolts.
It is provided with a pin that penetrates the cylinder cover and the second bracket to the left and right.
A work machine characterized in that a gap is interposed between the inner diameter of a pin hole of the second bracket and the cylinder cover through which the pin is passed and the outer diameter of the pin. In the work machine according to claim 1,
The upper edge of the cylinder cover faces the lower surface of the boom with a gap.
The pin is provided in only one place when viewed from the left and right, and is located on the tip end side of the boom in the cylinder cover.
A work machine characterized in that when the support by the plurality of bolts is lost, the boom base end side of the cylinder cover is displaced downward with the pin as a fulcrum. The work machine according to claim 1, wherein the first bracket and the second bracket are integrated. The work machine according to claim 1, wherein the pin passes between the arm cylinder and the boom to the left and right. The work machine according to claim 1, wherein the pin is divided into left and right.

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