JP3587697B2 - Hydraulic cylinder protection structure - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a protection device for a hydraulic cylinder mainly mounted on a working device such as a construction machine or a working vehicle.
[0002]
[Prior art]
FIG. 13 is a side view showing a hydraulic excavator (backhoe) provided with a conventional protection device for a boom cylinder 10 described in Japanese Utility Model Publication No. 4-37977. FIG. 14 is an enlarged detailed view of the conventional boom cylinder 10 shown in FIG. According to the boom cylinder protection device shown in FIGS. 13 and 14, the boom 9a having the arm 9b and the bucket 13 attached to the distal end is attached to the body 1 so as to be vertically swingable. The boom cylinder 10 for driving the boom 9a is provided such that the cylinder cylinder 10a is below the boom 9a and the piston rod 10b is connected to the boom 9a. A protective cover 14 is attached to the vicinity of the distal end of the piston rod 10b via a bolt 15, and is slidably connected to a plate-like support member 16 welded to a front collecting portion of the cylinder cylinder 10a. ing.
[0003]
[Problems to be solved by the invention]
In the protection device of one embodiment of the prior art shown in FIGS. 13 and 14, the protection cover 14 for protecting the piston rod 10b is formed by a single long plate, so that when the boom cylinder 10 is reduced in size, The piston rod 10b is covered on the cylinder cylinder 10a by the expansion and contraction stroke (a range in the drawing).
[0004]
In the case of a hydraulic shovel, a suspended load operation may be performed by a working device. In some cases, a holding function valve is attached to a boom cylinder to prevent the boom from lowering in a suspended load state. The holding function valve is preferably directly connected to the oil chamber on the head side of the cylinder. Therefore, it is desired that the holding function valve be directly mounted on the outer circumference of the cylinder cylinder of the boom cylinder. It is necessary to avoid contact of the holding function valve, and the mounting position of the holding function valve is considerably restricted. This also applies to the wiring and arrangement of the hydraulic piping and piping parts for the boom cylinder, regardless of the holding function valve.
[0005]
The present invention provides a hydraulic cylinder which can protect the piston rod of the hydraulic cylinder and can be efficiently configured without restricting the mounting, routing, and arrangement of hydraulic equipment, hydraulic piping, piping parts, etc. around the cylinder cylinder. A protection device is provided.
[0006]
[Means for Solving the Problems]
A first protection member fixed at one end near the tip of a piston rod of the hydraulic cylinder, and a slider fixed slidably to a slider fixed near the rod-side tip of the cylinder cylinder of the hydraulic cylinder; And a second protection member slidably connected to the hydraulic cylinder in the axial direction thereof, wherein the maximum length of the first protection member and the second protection member is added when the piston rod is fully extended. When the piston rod is minimized, the first protection member and the second protection member are housed in each other, so that the entire length is on the outer periphery of the hydraulic cylinder on the cylinder cylinder base side. It is shortened so as not to interfere with the devices to be arranged.
[0007]
According to this, when the hydraulic cylinder is extended, the first protection member and the second protection member can be a protection member having a length close to the sum of the respective lengths, and the piston rod can be protected. When the hydraulic cylinder is reduced, the first protection member and the second protection member can be in a state of being overlapped, so that the protection member has a length substantially equal to the length of the first protection member or the second protection member. Thus, the hydraulic equipment, hydraulic piping, piping components, and the like can be laid out with a margin on the outer periphery of the cylinder of the hydraulic cylinder.
[0008]
Furthermore, the first protection member has a rail portion in the axial direction of the hydraulic cylinder, and the second protection member is slidably fitted to the rail portion of the first protection member. The second protection member has a rail portion in the axial direction of the hydraulic cylinder, and the slider is slidably fitted to the rail portion of the second protection member, so that the second protection member is the first protection member. And the slider is slid and guided by the rail portion of the second protection member, so that a smooth extension or contraction operation can be performed.
[0009]
Still further, first escape preventing means for preventing the second protection member from slipping out of the rail portion of the first protection member in the sliding direction, and a second escape prevention means for preventing the slider from slipping out of the rail portion of the second member. 2 means for preventing slipping out.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side view of a hydraulic excavator 4 having a boom cylinder 3 provided with a rod protection device 2 according to an embodiment of the present invention. In the figure, 6 is a lower traveling body of the excavator 4, 7 is an upper revolving body, 19 is a working device for side excavation mounted on the upper revolving structure 7, 20 is a lower boom of a working device 19 for side excavation, 21 Is an offset boom, 22 is an upper boom, 23 is an arm, 24 is a bucket, 25 is an arm cylinder, 26 is a bucket cylinder, and 27 is an offset cylinder.
[0011]
FIG. 2 is an enlarged view showing the boom cylinder 3 and the protection device 2 for the piston rod of the hydraulic cylinder in the extended state in FIG. In the figure, 28 is a cylinder cylinder of the boom cylinder 3, 29 is a rod (specifically, a piston rod), and 30 is fixedly attached to an outer peripheral portion on the base side of the cylinder cylinder 28, and the bottom-side oil chamber ( (Not shown), an oil-tightness holding function valve (holding valve) for holding oil-tightly, 31 is a pressure oil supply / discharge conduit leading to a rod-side oil chamber (not shown) of the boom cylinder 3, 32 is a rod 29. An outer rail cover 35 serving as a first protection member fixedly attached to a tip end portion (to which the mounting seat boss 33 is welded) by tightening a bolt 34 is provided inside the outer rail cover 32 so as to be freely inserted and stored. An inner rail cover 36 serving as a second protection member is fixedly attached to an outer peripheral portion of the cylinder cylinder 28 on the rod side by tightening a band 37, and is attached to the inner rail. 5 a support guide for supporting members, 38 is a slider supporting member 36. FIG. 3 is a diagram showing a state in which the boom cylinder 3 in FIG. 2 has been contracted. In the figure, reference numeral 39 denotes a hook part which constitutes first escape prevention means fixed to the outer peripheral surface of the outer rail cover 32 facing the boom cylinder 3, and reference numeral 40 denotes a hook part of the outer rail cover 32 when the boom cylinder 3 extends. The hook portion 41 of the inner rail cover 35 which constitutes the first slip-out preventing means provided so as to be hooked and abuttable on 39, and the inner rail cover 35 is attached to the outer rail cover at a point in time when the boom cylinder 3 is expanding and contracting. 32 is a stopper that constitutes a second escape prevention unit that prevents the inside of the inside 32 from entering. FIG. 4 is a view as viewed from A in FIG. 3, but for clarity, a part of the boom cylinder 3 and a part of the hydraulic piping are shown by phantom lines.
[0012]
FIG. 5 is a view showing a cross section of the rod protection device 2 in FIG. FIG. 6 is a diagram viewed from CC in FIG. FIG. 7 is a front view of the outer rail cover 32 in FIG. In the drawing, reference numeral 42 denotes a bolt hole for inserting the bolt 34, and 43 (a portion indicated by hatching) denotes a synthetic resin film (for example, a nylon film) coated on the inner peripheral surface and the outer peripheral surface of the open end of the outer rail cover 32. is there. FIG. 8 is a diagram viewed from D in FIG. FIG. 9 is a side view as viewed from E in FIG. FIG. 10 is a front view of the inner rail cover 35 in FIG. In the figure, reference numeral 44 denotes a mounting hole for fixing the stopper 41. FIG. 11 is a view as viewed from F in FIG. FIG. 12 is a side view as viewed from G in FIG.
[0013]
Next, the configuration and operation of the rod protection device 2 of the present embodiment will be described with reference to FIGS. In the present embodiment, for example, the rod 29 of the boom cylinder 3 among the hydraulic cylinders (3, 25, 26, 27) mounted on the side excavating work device 19 mounted on the upper swing body 7 of the hydraulic excavator 4 As a protective cover, a divided (divided into two) outer rail cover 32 and an inner rail cover 35 are formed, and the inner rail cover 35 can be inserted and stored inside the outer rail cover 32 in a longitudinal direction, When the boom cylinder 3 is extended, the two rail covers 32 and 35 are connected to each other to be in an extended state. When the boom cylinder 3 is contracted, the inner rail cover 35 is stored in the outer rail cover 32. I made it.
[0014]
According to this, when the boom cylinder 3 is extended, the two rail covers 32 and 35 are in an extended state in a connected state, and cover one outer peripheral surface of the rod 29 portion of the boom cylinder 3. For example, it is possible to prevent the debris (not shown) excavated and held in the upper bucket 24 shown in FIG. 1 from falling and damaging the rod 29 of the boom cylinder 3. When the boom cylinder 3 is contracted, the two short rail covers 32 and 35 are housed in each other (when the rail covers 32 and 35 are in the housed state as shown in FIG. S, but the dimension S is a short dimension that is about 1/2 of the total length L 'of the cylinder cylinder 28), so that the cylinder rail 28 does not interfere with the two rail covers 32 and 35, Necessary equipment, for example, an oil-tightness functioning valve (holding valve) can be arranged around the base side of the cylinder 28.
[0015]
Further, hook portions 39 and 40 which can be hooked and contacted with each other when the boom cylinder 3 is extended are fixed to the outer rail cover 32 and the inner rail cover 35, respectively. Thereby, when the boom cylinder 3 is extended, the hook portion 39 of the outer rail cover 32 with respect to the hook portion 40 of the inner rail cover 35 from the middle extension time of the boom cylinder 3 to the maximum extension, Since the outer rail cover 32 and the inner rail cover 35 are connected to each other, they are extended as shown in FIG. When the boom cylinder 3 is contracted, the hooking contact between the hooks 39 and 40 is released, and the rod of the outer rail cover 32 is reduced from the intermediate contraction of the boom cylinder 3 to the minimum contraction. Since the outer rail cover 32 and the inner rail cover 35 are pulled back at the front end mounting portion (refer to the mounting seat boss 33 in FIG. 5), the length of the outer rail cover 32 and the inner rail cover 35 is short (the length having the dimension S shown in FIG. 3). ) Can be stored.
[0016]
Further, the inner rail cover 35 is guided by a slider 38 of a support member 36 fixedly attached to the outer peripheral portion of the cylinder tube 28 on the rod side, and the hook portion 40 of the inner rail cover 35 is The hook portion 39 of the outer rail cover 32 is located on a side closer to the rod 29 than the member 36, and the hook portion 39 of the outer rail cover 32 does not interfere with the support member when the boom cylinder 3 expands and contracts (the boom of the outer rail cover 32). (Left and right sides of the outer peripheral surface facing the cylinder 3).
[0017]
Thus, when the boom cylinder 3 expands and contracts, the outer rail cover 32 moves integrally with the rod 29 of the boom cylinder 3, and the inner rail cover 35 is supported and guided by the guide support 38. You. Further, since the hook portion 40 of the inner rail cover 35 is located on the side closer to the rod 29 than the guide plate 36, the hook portion 40 of the outer rail cover 32 in which the inner rail cover 35 relatively moves out is operated. It is possible to prevent a problem that the opening end (opening end indicated by reference character C in FIG. 6) comes off to the outside. Even if the hook portion 39 of the outer rail cover 32 is provided near the opening end, the hook portion 39 of the inner rail cover 35 does not interfere with the guide plate 36 when the boom cylinder 3 expands and contracts. Can be hooked and contacted.
[0018]
Further, as shown in FIG. 7, a synthetic resin coating 4 (for example, nylon coating) for preventing generation of abnormal noise and suppressing sliding abrasion is provided on at least the inner peripheral surface of the open end (portion indicated by reference character C) of the outer rail cover 32. ) Was applied. Thereby, it is possible to prevent rattling and sliding noise from being generated between the outer rail cover 35 and the inner rail cover 35 fitted inside the outer rail cover 32, Wear due to sliding resistance with the rail cover 32 can be suppressed. Further, when the coating of the synthetic resin film 43 is performed on the inner peripheral surface and the outer peripheral surface of the opening end, the film strength and the coating processability can be improved.
[0019]
【The invention's effect】
According to the protection device for a hydraulic cylinder of the present invention, when the hydraulic cylinder is extended, the first protection member and the second protection member can be a protection member having a length close to the sum of the respective lengths. Can be protected. When the hydraulic cylinder is reduced, the first protection member and the second protection member can be in a state of being overlapped, so that the protection member has a length substantially equal to the length of the first protection member or the second protection member. Thus, the hydraulic equipment, hydraulic piping, piping components, and the like can be laid out with a margin on the outer periphery of the cylinder of the hydraulic cylinder, and productivity or maintenance can be improved.
[Brief description of the drawings]
FIG. 1 is a partially cutaway side view of a hydraulic excavator having a boom cylinder provided with a rod protection device according to an embodiment of the present invention.
FIG. 2 is an enlarged view showing the boom cylinder in an extended state in FIG. 1;
FIG. 3 is a diagram showing a state in which a boom cylinder in FIG. 2 has been contracted.
FIG. 4 is a view as viewed from A in FIG. 3;
5 is a view showing a cross section of the rod protection device shown in FIG.
FIG. 6 is a diagram viewed from CC in FIG. 5;
FIG. 7 is a front view of the outer rail cover in FIG. 6;
FIG. 8 is a view as viewed from D in FIG. 7;
FIG. 9 is a side view as viewed from E in FIG. 7;
FIG. 10 is a front view of the inner rail cover in FIG. 4;
FIG. 11 is a diagram viewed from F in FIG. 10;
FIG. 12 is a side view as viewed from G in FIG. 10;
FIG. 13 is a side view showing a backhoe provided with a protection structure according to one embodiment of a conventional boom cylinder.
FIG. 14 is an enlarged detail view of the prior art boom cylinder of FIG.
[Explanation of symbols]
2 Protective device for rod 3, 10 Boom cylinder (boom cylinder)
4 Hydraulic excavator 9a Boom 9b, 23 Arm 19 Working device for side excavation 20 Lower boom 21 Offset boom 28 Cylinder cylinder 29 Rod (piston rod)
30 oil-tight holding function valve 32 outer rail cover (first holding member)
33 Mounting seat boss 35 Inner rail cover (second protection member)
36 Supporting member 38 Slide 39,40 Hook 43 Synthetic resin coating

Claims (3)

A first protection member having one end fixed near the tip of the piston rod of the hydraulic cylinder;
Wherein while being slidably connected to the slider fixed to the vicinity of the rod-side tip of the cylinder tube of the hydraulic cylinder, the Ru is slidably connected in the axial direction of the hydraulic cylinder relative to the first protective member 2 possess a protective member,
At the maximum extension of the piston rod, the first protection member and the second protection member have a combined length to protect the piston rod,
When the piston rod is minimized, the first protection member and the second protection member are housed in each other, so that the entire length does not interfere with devices arranged on the outer periphery of the hydraulic cylinder on the cylinder cylinder base side. A protection device for a hydraulic cylinder, characterized in that it is shortened as described above . The first protection member has a rail portion in the axial direction of the hydraulic cylinder, the second protection member is slidably fitted to the rail portion of the first protection member, and further includes the second protection member. 2. The hydraulic cylinder protection device according to claim 1, wherein the slider has a rail portion in the axial direction of the hydraulic cylinder, and the slider is slidably fitted into the rail portion of the second protection member. 3. A first exit prevention means for preventing the exit from the rail portion of the first member in the sliding direction of the second protective member, the second escape prevention to prevent the escape of the slider from the rail portion of the second protective member 3. The protection device for a hydraulic cylinder according to claim 2, further comprising means.

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