JP7368282B2 - excavator - Google Patents

Description

The present disclosure relates to excavators.

2. Description of the Related Art Conventionally, a tension adjustment device provided in a frame of a tracked vehicle is known (for example, see Patent Document 1). This tension adjustment device is a device for adjusting the tension of the crawler track, and is configured to be extended by injecting grease into a volume chamber surrounded by a cylinder tube and a piston rod. Further, this tension adjustment device is configured such that grease injected through a supply valve provided on an end surface of the piston rod flows into the volume chamber through a greasing path extending along the central axis of the piston rod. There is.

Japanese Patent Application Publication No. 9-193855

However, in this tension adjustment device, since the supply valve is provided on the end surface of the piston rod, the end surface of the piston rod cannot be brought into contact with the partition wall provided inside the frame. Therefore, in this tension adjustment device, it is necessary to bring the flange provided on the circumferential surface of the piston rod into contact with the partition wall so that the partition wall can receive the force acting on the piston rod. As described above, in this tension adjustment device, the structure of the piston rod is complicated.

Therefore, it is desirable that the end surface of the piston rod constituting the shock absorber capable of adjusting the tension of the crawler track be brought into contact with the partition wall of the frame.

An excavator according to an embodiment of the present invention is an excavator equipped with an undercarriage including a driven wheel and a shock absorber that supports the driven wheel so as to be movable in the front-rear direction, and the shock absorber includes a piston rod and a shock absorber. a cylinder tube, and a greasing port is provided on the outer circumferential surface of the piston rod such that it cannot rotate relative to the piston rod around the central axis of the piston rod . The frame of the lower traveling body is provided with a greasing opening, and the greasing port is arranged to face the opening, and the piston rod A greasing passage connecting the volume chamber and the greasing port is provided inside.

In the above-mentioned excavator, the end surface of the piston rod constituting the shock absorber capable of adjusting the tension of the crawler track can be brought into contact with the partition wall of the frame.

FIG. 1 is a side view of an excavator according to an embodiment of the present invention. It is a perspective view of the frame of an undercarriage body. It is a figure showing an example of composition of a buffer device. It is a figure which shows the movement of a shock absorber. FIG. 3 is a view of a piston rod with a grease nipple attached; It is a side view of a rotation stop block.

Hereinafter, a shovel 100 according to an embodiment of the present invention will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same reference numerals are given to the same components in each drawing, and redundant description will be omitted.

Note that in the following description, the X axis, Y axis, and Z axis are mutually perpendicular axes. The X-axis corresponds to the front-rear axis of the shovel 100, with the front of the shovel 100 corresponding to the positive direction of the X-axis, and the rear of the shovel 100 corresponding to the negative direction of the X-axis. The Y-axis corresponds to the left-right axis of the shovel 100, with the left side of the shovel 100 corresponding to the positive direction of the Y-axis, and the right side of the shovel 100 corresponding to the negative direction of the Y-axis. The Z-axis corresponds to the rotation axis of the shovel 100, the upper side of the shovel 100 corresponds to the positive direction of the Z-axis, and the lower side of the shovel 100 corresponds to the negative direction of the Z-axis. In the example of FIG. 1, the X and Y axes extend horizontally, and the Z axis extends vertically.

First, an outline of the shovel 100 will be explained with reference to FIG. FIG. 1 is a side view of shovel 100.

The excavator 100 includes a crawler-type lower running body 1. An upper rotating body 3 is mounted on the lower traveling body 1 via a rotating mechanism 2. A boom 4 is attached to the upper revolving body 3. An arm 5 is attached to the tip of the boom 4, and a bucket 6 is attached to the tip of the arm 5. The boom 4, arm 5, and bucket 6 constitute a digging attachment that is an example of an attachment. The boom 4 is driven by a boom cylinder 7. The arm 5 is driven by an arm cylinder 8. The bucket 6 is driven by a bucket cylinder 9. A power source such as an engine 11 is mounted on the upper revolving body 3. Further, a cabin 10 is installed in the upper revolving body 3.

The lower traveling body 1 mainly includes a frame 12, a crawler belt 13, a carrier roller 14, a track roller 15, a traveling hydraulic motor 16, a driven wheel 17, and the like.

The frame 12 is a member that forms the skeleton of the lower traveling body 1. A carrier roller 14 , a track roller 15 , a traveling hydraulic motor 16 , and a driven wheel 17 are attached to the frame 12 .

The crawler belt 13 is an endless track (crawler belt) that is rotationally driven by a traveling hydraulic motor 16 . The crawler belt 13 meshes with a drive sprocket (not shown) coupled to a rotating shaft of a traveling hydraulic motor 16 and a driven wheel 17, respectively.

The carrier roller 14 is a driven roller disposed above the frame 12 (+Z side) between the frame 12 and the crawler belt 13. The track roller 15 is a driven roller disposed below the frame 12 (-Z side) between the frame 12 and the crawler belt 13.

The traveling hydraulic motor 16 is attached to the rear end (-X side end) of the frame 12. The lower traveling body 1 is driven by a hydraulic motor 16 for traveling.

The driven wheel 17 is attached to the front end (+X side end) of the frame 12. Therefore, the driven wheel 17 is also called a front idler. The driven wheels 17 are attached to the frame 12 via a shock absorber 50 (see FIG. 2).

The shock absorber 50 is configured so that the tension of the crawler belt 13 can be adjusted. In this embodiment, the shock absorber 50 is arranged between the frame 12 and the crawler belt 13 so that the tension of the crawler belt 13 can be maintained at an appropriate level. The tension state of the crawler belt 13 increases, for example, when a foreign object such as a stone is caught inside the crawler belt 13, that is, between the frame 12 and the crawler belt 13. This is because the circumference of the crawler belt 13 tends to increase. In this case, the excavator 100 can relieve the tension of the crawler belt 13 by moving the driven wheel 17 rearward using the shock absorber 50, and can prevent the tension of the crawler belt 13 from increasing excessively.

Furthermore, when the front end of the lower traveling body 1 comes into contact with an obstacle such as a rock, the shovel 100 can reduce the impact by moving the driven wheels 17 rearward using the shock absorber 50.

FIG. 2 is a perspective view of the frame 12. As shown in FIG. 2, the frame 12 includes a central frame portion 12C connected to the turning mechanism 2, a left frame portion 12L connected to the +Y side of the central frame portion 12C, and a left frame portion 12L connected to the −Y side of the central frame portion 12C. It has a right frame portion 12R to which it is coupled.

Specifically, as shown in FIG. 2, the driven wheels 17 include a left driven wheel 17L and a right driven wheel 17R, and the shock absorber 50 includes a left shock absorber 50L and a right shock absorber 50R. The left driven wheel 17L is attached to the front end of the left frame section 12L via the left shock absorber 50L, and the right driven wheel 17R is attached to the front end of the right frame section 12R via the right shock absorber 50R.

The crawler belt 13 includes a left crawler belt 13L and a right crawler belt 13R, the carrier roller 14 includes a left carrier roller 14L and a right carrier roller 14R, and the track roller 15 includes a left track roller 15L and a right track roller 15R. The traveling hydraulic motor 16 includes a left traveling hydraulic motor 16L and a right traveling hydraulic motor 16R. In addition, in FIG. 1, the right crawler belt 13R, the right carrier roller 14R, the right track roller 15R, and the right travel hydraulic motor 16R are invisible.

With this configuration, when the traveling hydraulic motor 16 rotates counterclockwise in FIG. 1, the crawler belt 13 also rotates counterclockwise, and the shovel 100 moves forward. Conversely, when the traveling hydraulic motor 16 rotates clockwise, the crawler belt 13 also rotates clockwise, and the shovel 100 moves backward.

Next, details of the frame 12 will be explained with reference to FIG. 2. Although the following description relates to the left frame portion 12L, it similarly applies to the right frame portion 12R.

The left frame portion 12L is provided with a front step FST and a rear step RST. The front step FST and the rear step RST are typically used as scaffolding when a worker gets on and off the cabin 10.

Further, the left frame portion 12L is provided with a front pedestal FPD and a rear pedestal RPD for attaching the left carrier roller 14L. A front opening FOP is formed on the outside (+Y side) of the front pedestal FPD, and a rear opening ROP is formed on the outside (+Y side) of the rear pedestal RPD.

The front opening FOP is formed outside the front pedestal FPD to prevent dirt from accumulating on the upper surface of the left frame portion 12L. That is, the front opening FOP is formed so that the earth and sand that is drawn into the rotating left crawler belt 13L and hits the left carrier roller 14L on the front side falls to the ground without staying on the upper surface of the left frame part 12L.

Similarly, the rear opening ROP is formed outside the rear pedestal RPD to prevent dirt from accumulating on the upper surface of the left frame portion 12L. That is, the rear opening ROP is formed so that the earth and sand that is drawn into the rotating left crawler belt 13L and hits the rear left carrier roller 14L falls to the ground without remaining on the upper surface of the left frame portion 12L. There is.

Note that the upper surface of the left frame portion 12L is sloped so that the outside (+Y side) is lower than the inside (-Y side) to prevent dirt from accumulating (see FIG. 3(C)). That is, the left frame portion 12L is configured such that earth and sand on the upper surface of the left frame portion 12L slides to the outside of the left frame portion 12L.

Further, a receiving portion RC configured to receive and support the left shock absorber 50L is provided at the front end portion of the left frame portion 12L.

Specifically, the receiving portion RC is configured to receive and support bearing portions SH attached to both sides of the left driven wheel 17L so as to support the rotation axis of the left driven wheel 17L. Note that the bearing portion SH is also referred to as a hub unit. In the example shown in FIG. 2, the receiving part RC has a guide rail structure that supports the bearing part SH so that the bearing part SH can slide in the X-axis direction.

Next, details of the shock absorber 50 will be described with reference to FIG. 3. FIG. 3 is a diagram showing an example of the configuration of the shock absorber 50. Specifically, FIG. 3(A) is a sectional view of the left shock absorber 50L attached to the front end of the left frame portion 12L. FIG. 3(A) corresponds to a diagram of a cross section in the XZ plane including the dashed-dotted line L1 shown in FIG. 2, viewed from the +Y side. However, in FIG. 3A, for clarity, only the left frame portion 12L and the left shock absorber 50L (excluding the piston rod 51) are shown in cross section, and the left carrier roller 14L, left track roller 15L, and left driven The wheel 17L, the piston rod 51, and the bearing portion SH are not shown in cross section. FIG. 3(B) is a side view of the rear end (-X side end) of the left shock absorber 50L installed inside the left frame portion 12L when viewed from the -Y side. be. FIG. 3(C) is a diagram of a cross section in the YZ plane including the dashed line L2 shown in FIG. 3(A) when viewed from the +X side. Although the following description relates to the left frame portion 12L, it similarly applies to the right frame portion 12R.

The left shock absorber 50L mainly includes a piston rod 51, a cylinder tube 52, a threaded rod 53, a yoke 54, a spring 55, a grooved nut 56, and a spring pin 57. Most of the left shock absorber 50L is housed in a space between the front end wall FEW of the left frame portion 12L and a partition wall PW provided within the left frame portion 12L.

Each of the piston rod 51, cylinder tube 52, and threaded rod 53 is a member for partitioning the volume chamber VC. The volume chamber VC is a chamber in which fluid such as grease is accommodated. The length of the left shock absorber 50L in the longitudinal direction (X-axis direction) is increased by increasing the volume of the volume chamber VC, that is, by increasing the amount of fluid accommodated in the volume chamber VC.

In the example shown in FIG. 3A, the volume chamber VC includes the front end surface of the piston rod 51 (the end surface on the +X side), the inner peripheral surface of the cylinder tube 52, and the rear end surface of the threaded rod 53 (the end surface on the -X side). It is a cylindrical space separated by an end surface.

The piston rod 51 is configured such that its rear end surface (-X side end surface) contacts a partition wall PW provided inside the left frame portion 12L. The piston rod 51 is configured to remain in contact with the partition wall PW even when the volume chamber VC expands due to fluid flowing into the volume chamber VC.

The cylinder tube 52 is configured to be able to slide on the circumferential surface of the piston rod 51 and move forward (in the +X direction) when the volume chamber VC expands due to fluid flowing into the volume chamber VC. There is.

The threaded rod 53 is configured to close an opening on the front side (+X side) of the cylinder tube 52. The threaded rod 53 is configured to be able to move forward (in the +X direction) together with the cylinder tube 52 when the volume chamber VC expands due to fluid flowing into the volume chamber VC.

The yoke 54 is configured to support the left driven wheel 17L so that the left driven wheel 17L can move rearward (in the -X direction). In the example shown in FIG. 3(A), the yoke 54 is fixed to a bearing portion SH that supports the rotation shaft of the left driven wheel 17L.

The spring 55 is configured to generate a repulsive force that pushes the yoke 54 back forward (in the +X direction) when the yoke 54 moves backward (in the -X direction).

The grooved nut 56 is configured to limit forward (+X direction) relative movement of the yoke 54 with respect to the threaded rod 53.

In the example shown in FIG. 3A, the threaded rod 53 is configured to have a male thread on the circumferential surface of the cylindrical front end (+X side end). The cylindrical front end is inserted into a through hole formed in the rear end surface of the yoke 54, and is configured to protrude into a cylindrical space formed inside the yoke 54. A grooved nut 56 is screwed onto the front end projecting into this space.

The spring pin 57 is a member for preventing the grooved nut 56 from rotating with respect to the threaded rod 53. In the example shown in FIG. 3A, the spring pin 57 passes through a groove formed at the tip of the grooved nut 56 and is inserted into a through hole formed at the front end of the threaded rod 53. This through hole is formed to extend in a direction perpendicular to the central axis of the cylindrical front end.

Here, with reference to FIG. 4, the movement of the shock absorber 50 when the driven wheel 17 moves rearward will be described. FIG. 4 is a diagram showing the movement of the shock absorber 50, and corresponds to FIG. 3(A). Specifically, FIG. 4(A) shows the state of the left shock absorber 50L before the left driven wheel 17L moves backward, and FIG. 4(B) shows the state of the left driven wheel 17L after the left driven wheel 17L moves backward by a distance D1. The state of the left shock absorber 50L after the above is shown.

Specifically, before the left driven wheel 17L moves rearward, the grooved nut 56 screwed onto the front end of the threaded rod 53 is inserted into the inside of the yoke 54, as shown in FIG. 4(A). It is in contact with the inner surface of the rear side (−X side) of the yoke 54 in the cylindrical space formed in the cylindrical space. The spring 55 is held between the flange portion 52F of the cylinder tube 52 and the flange portion 54F of the yoke 54 while being slightly compressed in the front-rear direction. The flange portion 52F of the cylinder tube 52 is configured to protrude in the radial direction from the circumferential surface of the rear end portion of the cylinder tube 52. Similarly, the flange portion 54F of the yoke 54 is configured to protrude in the radial direction from the circumferential surface of the rear end portion of the yoke 54.

When the left driven wheel 17L moves rearward, the yoke 54 moves rearward together with the left driven wheel 17L, as shown in FIG. 4(B). On the other hand, the piston rod 51, cylinder tube 52, and threaded rod 53 do not move rearward even if the left driven wheel 17L moves rearward. Therefore, the inner surface of the rear side (−X side) of the yoke 54 moves backward (in the −X direction) away from the grooved nut 56, as shown in FIG. 4(B). Then, the flange portion 54F of the yoke 54 also moves rearward (in the −X direction), as shown in FIG. 4(B). As a result, the spring 55 held between the flange portion 52F of the cylinder tube 52 and the flange portion 54F of the yoke 54 is compressed and stores a repulsive force. This repulsive force causes the yoke 54 to move forward until the inner surface of the rear side (-X side) of the yoke 54 comes into contact with the grooved nut 56 when the force trying to move the left driven wheel 17L backward weakens. Push back and try to return the left driven wheel 17L to its original position.

Next, the grease nipple 51N will be explained with reference to FIGS. 3 and 5. FIG. 5 is a diagram of the piston rod 51 with the grease nipple 51N attached. Specifically, FIG. 5(A) is a perspective view of the piston rod 51, and FIG. 5(B) is a rear view of the piston rod 51.

The grease nipple 51N is an example of a fluid injection mechanism for injecting grease, which is an example of a fluid contained in the volume chamber VC.

In this embodiment, the grease nipple 51N is screwed into the circumferential surface CS of the piston rod 51 so as to extend perpendicularly to the central axis CA of the piston rod 51, as shown in FIG. 5(A).

Further, a retainer 51S is engaged with the grease nipple 51N. The retainer 51S is formed of a substantially L-shaped metal plate, as shown in FIG. 5(B). One end of the retainer 51S is fixed to the circumferential surface CS of the piston rod 51 by a bolt 51B. Note that the bolt 51B is screwed into the circumferential surface CS of the piston rod 51 at an angular position where an angle α is formed between the central axis NA of the grease nipple 51N and the central axis BA of the bolt 51B.

As shown in FIG. 5(A), a U-shaped notch CT is formed at the other end of the retainer 51S. As shown in FIG. 5(B), the retainer 51S is positioned and fixed to the circumferential surface CS of the piston rod 51 so that the constriction CR of the grease nipple 51N and the notch CT engage with each other. The retainer 51S can prevent the grease nipple 51N from popping out in the radial direction due to the high-pressure grease stored in the volume chamber VC when the operator removes the grease nipple 51N.

As shown in FIG. 3(C), the piston rod 51 is formed with a greasing passage 51T that extends parallel to the central axis of the piston rod 51. Therefore, grease injected from a grease gun (not shown) or the like through the grease nipple 51N flows into the volume chamber VC through the grease nipple 51N and the greasing path 51T, expands the volume chamber VC in the +X direction, and causes the left driven wheel to 17L can be pressed against the inner surface of the crawler belt 13.

For example, when an operator who inspects the tension of the crawler belt 13 detects that the amount of slack in the crawler belt 13 exceeds a predetermined value, he/she can correct the amount of slack by additionally injecting grease into the volume chamber VC through the grease nipple 51N. It can be adjusted to below a predetermined value.

Next, with reference to FIG. 3, the support structure SP that supports the left shock absorber 50L inside the left frame portion 12L will be described.

The support structure SP is a member welded to the inner wall of the left frame portion 12L, and is configured to come into contact with the flange portion 52F of the cylinder tube 52 to support the left shock absorber 50L, as shown in FIG. 3(B). has been done.

Specifically, the support structure SP is composed of a pair of metal plates having a substantially L-shaped cross section, as shown in FIG. 3(C). The flange portion 52F of the cylinder tube 52 is configured to be able to slide on the support structure SP when an operator installs the left shock absorber 50L into the left frame portion 12L.

The lower surface of the left frame portion 12L is configured to be open at the center, as shown in FIG. 3(C). This is to prevent the left track roller 15L from coming into contact with the lower surface of the left frame portion 12L.

Further, as shown in FIG. 3(A), the partition wall PW is arranged on the front side (+X side) of the front opening FOP formed directly below the left carrier roller 14L on the front side. With this arrangement, the dirt carried by the left crawler belt 13L and hitting the left carrier roller 14L on the front side does not accumulate on the left shock absorber 50L even if it falls down through the front opening FOP. That is, these earth and sand fall to the ground through the opening formed in the lower surface of the left frame portion 12L, without accumulating on the left shock absorber 50L. Therefore, this arrangement can prevent dirt from accumulating on the left frame portion 12L directly below the left carrier roller 14L on the front side.

Next, the rotation prevention structure RT of the piston rod 51 will be described with reference to FIGS. 3 and 5. The anti-rotation structure RT is mainly composed of the pin 51P and the anti-rotation block BK. The anti-rotation block BK is an example of a rotation restriction part that restricts rotation of the piston rod 51 around the central axis, and the pin 51P is an example of a protrusion (guided part) that engages with the rotation restriction part.

The pin 51P is configured to prevent the piston rod 51 from rotating around the central axis in cooperation with the rotation stopper block BK when the left shock absorber 50L is attached to the left frame portion 12L. ing.

On the other hand, the pin 51P is configured so that when the operator attaches the left shock absorber 50L to the left frame portion 12L, the pin 51P cooperates with the rotation stop block BK to rotate the piston rod 51 around the central axis. has been done. Note that the piston rod 51 is rotated around the central axis CA (see FIG. 5(A)) until the rear end surface ES (see FIG. 5(A)) and the partition wall PW come into contact with each other. It is supported by the inner peripheral surface of the tube 52.

With this configuration, when attaching the left shock absorber 50L to the left frame portion 12L, the operator can insert the grease nipple 51N into the opening 12H (FIGS. 1, 2, and 3C) formed in the left frame portion 12L. ). That is, the piston rod 51 is rotated by the detent structure RT so that the grease nipple 51N is at an angular position (target angular position) extending toward the outside (+Y side), as shown in FIG. 5(B). Specifically, if the deviation from the target angular position of the grease nipple 51N is within a predetermined angular range (-β to +β), the piston rod 51 rotates so that the angular position of the grease nipple 51N becomes the target angular position. It is rotated by the stop structure RT.

The opening 12H is formed so that the operator can use it when injecting grease into the left shock absorber 50L. In this embodiment, the opening 12H is formed at a lower position than the front step FST, as shown in FIG. Further, the opening 12H is formed such that the central axis NA of the grease nipple 51N passes approximately through the center of the opening 12H, as shown in FIG. 3(C). That is, the grease nipple 51N positioned at the target angular position is arranged so that the central axis NA passes approximately through the center of the opening 12H.

Next, with reference to FIG. 6, a configuration example of the detent block BK will be described. FIG. 6 is a side view of the detent block BK when the detent block BK is viewed from the +Y side. Specifically, FIG. 6(A) shows an example of the dimensions of each part of the detent block BK. FIG. 6(B) shows an example of the positional relationship between the detent block BK and the pin 51P when the operator attaches the shock absorber 50 to the frame 12. Note that the following description relates to the left frame portion 12L, but is similarly applied to the right frame portion 12R.

As shown in FIGS. 3(B) and 3(C), the detent block BK is welded to a partition wall PW provided within the left frame portion 12L. Moreover, as shown in FIG. 3(C), the rotation stopper block BK is arranged on the opposite side of the grease nipple 51N with the piston rod 51 in between. When the detent block BK is arranged on the same side as the grease nipple 51N with respect to the piston rod 51, the dimensions and welding position of the detent block BK are limited in order to avoid contact between the grease nipple 51N and the detent block BK. This is to put it away. In this embodiment, since the detent block BK is placed on the opposite side of the grease nipple 51N with the piston rod 51 in between, it is not subject to restrictions regarding dimensions and welding positions, and as shown in FIG. 6(A). The desired height H1 and desired width W4 can be secured. However, the detent block BK may be placed on the same side of the piston rod 51 as the grease nipple 51N.

Moreover, as shown in FIG. 6(A), the detent block BK has a pair of guide portions GD that expand in a substantially V-shape toward the front (+X direction). The pin 51P is configured to mesh with a pair of guide portions GD, as shown in FIG. 3(B).

Specifically, the detent block BK is configured to receive the pin 51P between the pair of guide parts GD when the operator pushes the left shock absorber 50L into the left frame part 12L to attach it. More specifically, in the guide part GD, the operator slides the flange part 52F of the cylinder tube 52 on the support structure SP, and inserts the pin 51P screwed into the circumferential surface CS of the piston rod 51 backward (-X The pin 51P is configured to be received between the pair of guide portions GD when the pin 51P is moved in the direction (direction).

Each of the pair of guide parts GD has a curved part PT1 forming a semicircular outline for holding the pin 51P, and a straight part PT2 having a straight outline extending outward from the curved part PT1.

The straight line portion PT2 includes a pair of first straight line portions SG1 that spread forward from the curved portion PT1, a pair of second straight line portions SG2 that further spread forward from the pair of first straight line portions SG1, and a pair of second straight line portions SG2. It includes a pair of third straight portions SG3 that further widen toward the front.

The curved portion PT1 is centered on the point P1 and has a radius R1 that is slightly larger than the radius of the pin 51P.

An angle γ1 is formed between the pair of first straight portions SG1. An angle γ2 larger than angle γ1 is formed between the pair of second straight portions SG2. An angle γ3 larger than angle γ2 is formed between the pair of third straight portions SG3.

The minimum width between the pair of first straight portions SG1 is twice the radius R1, and the maximum width between the pair of first straight portions SG1 is width W1. Further, the minimum width between the pair of second straight portions SG2 is width W1, and the maximum width between the pair of second straight portions SG2 is width W2. Further, the minimum width between the pair of third straight portions SG3 is width W2, and the maximum width between the pair of third straight portions SG3 is width W3. Note that the maximum width of the detent block BK is the width W4, which is larger than the width W0 of the base of the detent block BK, which is the portion welded to the partition wall PW. Moreover, the width W4, which is the maximum width of the detent block BK, is larger than the height H1 (length in the front-rear direction (X-axis direction)) of the detent block BK.

With the above-described configuration, as shown in FIG. 6(B), the detent block BK utilizes the force of the operator to push the left shock absorber 50L backward (in the -X direction), and locks the pin 51P. A force is generated to move the piston rod 51 in the −Z direction, that is, a force to rotate the piston rod 51 around the central axis. The pin 51P slides on the surface of the straight portion PT2 in the order of the third straight portion SG3, the second straight portion SG2, and the first straight portion SG1, and reaches a position where it engages with the curved portion PT1.

Specifically, the pin 51Pa shown by a broken line represents the position of the pin 51P at a first time point, and the pin 51Pb shown by a broken line represents the position of the pin 51P at a second time point after the first time point, and is shown by a broken line. The pin 51Pc represents the position of the pin 51P at a third time point after the second time point. Further, the pin 51Pd indicated by a solid line represents the position of the pin 51P at the fourth time point after the third time point.

The position represented by the pin 51Pa corresponds to, for example, the angular position of the pin 51P when the deviation of the grease nipple 51N from the target angular position is −β (see FIG. 5(B)).

In this case, the pin 51P contacts the third straight portion SG3 at the first time point. Thereafter, the pin 51P moves toward the center of the guide portion GD while sliding on the surface of the third straight portion SG3. Thereafter, the pin 51P comes into contact with the second linear portion SG2 and moves further toward the center of the guide portion GD while sliding on the surface of the second linear portion SG2. Thereafter, the pin 51P contacts the first straight portion SG1 and moves further toward the center of the guide portion GD while sliding on the surface of the first straight portion SG1. Thereafter, the pin 51P stops at a fourth point in time, which is the point in time when the rear end surface ES of the piston rod 51 contacts the partition wall PW. At this time, the angular position of the grease nipple 51N is at the target angular position as shown in FIG. 3(B).

In the example shown in FIG. 6, the pair of guide parts GD are configured to have the same height, but even if one guide part GD is configured to be higher than the other guide part GD, good.

As described above, the excavator 100 according to the embodiment of the present invention includes the lower traveling body 1 including the driven wheels 17 and the shock absorber 50 that supports the driven wheels 17 so as to be movable in the front and rear directions. The shock absorber 50 has a piston rod 51 and a cylinder tube 52. A grease nipple 51N serving as a greasing port is provided on the circumferential surface CS, which is the outer circumferential surface of the piston rod 51. A greasing passage 51T connecting the volume chamber VC and the grease nipple 51N is provided inside the piston rod 51.

With this configuration, the excavator 100 can bring the rear end surface ES of the piston rod 51, which constitutes the shock absorber 50 that can adjust the tension of the crawler belt 13, into contact with the partition wall PW of the frame 12. Therefore, the excavator 100 can prevent the shape of the piston rod 51 from becoming complicated. Moreover, the shovel 100 can transmit the force acting on the piston rod 51 to the partition wall PW via the rear end surface ES of the piston rod 51, which has a simple shape (cylindrical shape).

The frame 12 of the lower traveling body 1 may be provided with a rotation stopper block BK as a rotation restricting portion that restricts rotation of the piston rod 51 around the central axis. In this case, the circumferential surface CS of the piston rod 51 may be provided with a pin 51P as a protrusion that engages with the detent block BK.

With this configuration, the excavator 100 can adjust the angular position of the grease nipple 51N to a desired angular position when the shock absorber 50 is assembled to the frame 12. For example, the excavator 100 can adjust the angular position of the grease nipple 51N to a desired angular position such that the tip of the grease nipple 51N is located approximately at the center of the greasing opening 12H formed in the frame 12. .

The anti-rotation block BK may have a pair of guide portions GD that expand in a substantially V-shape toward the front (+X direction). In this case, the pin 51P may be configured to mesh with the guide portion GD.

With this configuration, when the shock absorber 50 is assembled to the frame 12, the excavator 100 can adjust the angle of the grease nipple 51N even if there is a deviation between the angular position of the grease nipple 51N and the target angular position. The position can be adjusted to the target angular position. This is because the piston rod 51 can be rotated so that the angular position of the grease nipple 51N becomes the target angular position. Specifically, the piston rod 51 rotates as the shock absorber 50 moves rearward (in the −X direction). This is because the pin 51P comes into contact with the detent block BK. Note that the anti-rotation structure RT configured by the combination of the pin 51P and the anti-rotation block BK desirably allows the angular position of the grease nipple 51N to reach the target angle when the rear end surface ES of the piston rod 51 contacts the partition wall PW. configured to be in position.

The anti-rotation block BK is desirably arranged on the opposite side of the grease nipple 51N with the piston rod 51 in between.

With this configuration, the excavator 100 can prevent the grease nipple 51N from coming into contact with the rotation stopper block BK when the shock absorber 50 is assembled to the frame 12. However, the anti-rotation block BK may be arranged on the same side of the piston rod 51 as the grease nipple 51N.

The rear end surface ES of the piston rod 51 is configured to come into contact with a partition wall PW provided on the frame 12. The partition wall PW is preferably located on the front side (+X side) of the front opening FOP, which is an opening provided under the carrier roller 14.

With this configuration, the excavator 100 can prevent earth and sand from accumulating on the buffer device 50. If the buffer device 50 is located below the front opening FOP, the earth and sand that hits the carrier roller 14 and falls will accumulate on the buffer device 50, but in this configuration, the buffer device 50 is located below the front opening FOP. This is because it is located further forward than the partition wall PW located on the front side (+X side).

A retainer 51S may be provided on the circumferential surface CS of the piston rod 51 to prevent the grease nipple 51N from falling off.

With this configuration, the retainer 51S prevents the grease nipple 51N from flying away from the piston rod 51 due to the high-pressure grease stored in the volume chamber VC when the grease nipple 51N is removed from the piston rod 51. can.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above, and various modifications and substitutions can be made to the embodiments described above without departing from the scope of the present invention. can be added.

For example, in the above embodiment, the rotation prevention structure RT is configured by a combination of the pin 51P and the rotation prevention block BK, but it may be configured by a combination of the grease nipple 51N and the rotation prevention block BK. That is, the detent structure RT may be configured such that the grease nipple 51N engages with the detent block BK instead of the pin 51P. In this case, the grease nipple 51N functions as a protrusion (guided part) that engages with the rotation regulating part.

1...Lower traveling body 2...Swivel mechanism 3...Upper rotating body 4...Boom 5...Arm 6...Bucket 7...Boom cylinder 8...Arm cylinder 9... - Bucket cylinder 10... Cabin 11... Engine 12... Frame 12H... Opening 13... Crawler belt 14... Carrier roller 15... Track roller 16... Hydraulic motor for travel 17 ... Driven wheel 50 ... Shocking device 51 ... Piston rod 51B ... Bolt 51N ... Grease nipple 51P ... Pin 51T ... Greasing path 52 ... Cylinder tube 52F ... Flange part 53... Threaded rod 54... Yoke 54F... Flange part 55... Spring 56... Grooved nut 57... Spring pin 100... Shovel BA... Center shaft BK ...Stopper block CA...Central axis CR...Constriction CS...Circumferential surface CT...Notch ES...Rear end surface FEW...Front end wall FST...Front step FOP ...Front opening FPD...Front pedestal NA...Central axis PW...Partition wall RST...Rear step ROP...Rear opening RPD...Rear pedestal RT...Non-rotation structure SH...Bearing part SP...Support structure VC...Volume chamber

Claims (7)

An excavator equipped with a lower traveling body including a driven wheel and a shock absorber that supports the driven wheel so as to be movable in a longitudinal direction,
The shock absorber includes a piston rod and a cylinder tube,
A greasing port is provided on the outer circumferential surface of the piston rod so that it cannot rotate relative to the piston rod around a central axis of the piston rod ,
having a retainer that prevents the greasing port from falling off;
The frame of the lower traveling body is provided with an opening for greasing,
The greasing port is arranged to face the opening,
A greasing passage connecting the volume chamber and the greasing port is provided inside the piston rod.
shovel. The frame of the lower traveling body is provided with a rotation restriction portion that restricts rotation of the piston rod around a central axis,
A protrusion that engages with the rotation restriction portion is provided on the outer peripheral surface of the piston rod.
The excavator according to claim 1. The rotation regulating portion has a pair of guide portions that widen toward the front,
The protruding portion is configured to engage with the pair of guide portions.
The excavator according to claim 2. The rotation regulating portion is disposed on the opposite side of the greasing port with the piston rod interposed therebetween.
The excavator according to claim 2 or 3. The end surface of the piston rod is configured to contact a partition wall provided in a frame of the undercarriage body,
The partition wall is located in front of an opening provided under the carrier roller.
A shovel according to any one of claims 1 to 4. The outer peripheral surface of the piston rod is provided with the retainer that prevents the greasing port from falling off.
A shovel according to any one of claims 1 to 5. The retainer is fixed to the outer peripheral surface of the piston rod by a bolt screwed into the outer peripheral surface of the piston rod.
A shovel according to any one of claims 1 to 6.

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