JPH0544385Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a sliding device for reducing sliding resistance during expansion and contraction in a box-shaped telescopic boom used in hydraulic cranes, aerial work vehicles, etc. It is.

[Conventional technology]

In a box-shaped telescopic boom that is constructed by fitting an outer cylinder and an inner cylinder so that they can slide relative to each other, the outer cylinder and the inner cylinder are slidably fitted in order to reduce the sliding resistance (frictional resistance) during expansion and contraction. In the moving part, a slide pad made of a material with a small coefficient of friction such as plastic is provided on one sliding surface (for example, the outer side of the upper surface of the base end of the inner cylinder, which will be explained below using this example), and the frictional resistance of this slide pad is further increased. To reduce this, grease is applied to the sliding surface (top surface) of the slide pad.

However, as the slide pad moves in strong contact with the inside of the upper surface of the outer cylinder when the boom extends and retracts, most of this grease is pushed to both sides of the slide pad and adheres to the outer cylinder side, resulting in its lubricating effect being reduced. It was destined to be lost in a short period of time.

Conventionally, as a countermeasure for this point,
As shown in the publication, a dogleg-shaped scraper is installed in front of the slide pad, and when the boom extends and retracts, this scraper removes the grease that has been pushed away to both sides and adhered to the outer cylinder onto the line of movement of the slide pad. There is a known device designed to collect the materials and collect them on a slide pad.

[The problem that the idea aims to solve]

However, with this configuration, even if the scraper collects the grease on the line of movement of the slide pad, most of this grease is pushed aside again by the slide pad, and only a small amount is collected on the sliding surface of the pad. , it had become less effective.

Furthermore, in order for the slide pad to perform its original function, it is most desirable to install it at the proximal end of the inner cylinder, on the outside of the top surface, where it makes the strongest contact with the outer cylinder, and at the end in the left-right direction where it has a high load-bearing capacity. However, according to the conventional structure, a dogleg-shaped scraper is installed at a position shifted laterally from the pad on both the front and rear sides of the pad, so this scraper restricts the mounting position of the slide pad in both the front, rear, left, and right directions. The slide pad cannot be installed at the optimum position.

SUMMARY OF THE INVENTION Therefore, the present invention provides a sliding device for a telescopic boom that has an excellent grease recovery effect on the slide pad and allows the slide pad to be installed at the optimum position for its original function.

[Means to solve the problem]

In the present invention, a slide pad is provided on the sliding surface of either one of the outer cylinder and the inner cylinder that are relatively slidably fitted together to form a telescopic boom, and that slides into contact with the other sliding surface. At the same time, a grease stopper member made of an elastic body is provided on the side of the sliding surface on which the slide pad is provided in the direction of boom extension and contraction and in the linear direction, and a gap is formed between the slide pad and the other sliding surface. It is provided in a state in which it is in sliding contact with.

[Effect]

With this configuration, the grease stopper performs a damming function against the grease that is pushed aside to the side of the pad by the slide pad when the boom extends and retracts, so it prevents the grease from escaping to the side of the pad while preventing the grease that has been pushed away. can be efficiently collected on the slide pad. Further, since the mounting position of the slide pad is hardly restricted by the grease stopper, it is possible to install the slide pad at the optimum position for its original function.

〔Example〕

An embodiment of the present invention will be described with reference to the drawings.

A basic embodiment of the present invention is shown in FIGS. 1 to 5.

To explain this basic embodiment, a box-shaped telescopic boom B is constituted by an outer cylinder 1 and an inner cylinder 2 that is slidably fitted into the outer cylinder 1.
On both left and right sides of the outer upper surface of the base end of the inner cylinder 2,
A slide pad 3 made of a material with a small coefficient of friction, such as plastic, is provided in sliding contact with the inside of the upper surface of the outer cylinder 1 to reduce sliding resistance when the boom is extended and retracted. Note that since both the left and right sides of the slide pad 3 have the same configuration, only one of them will be illustrated and explained here.

The slide pad 3 is fixed on a pad carrier 4 attached to the inner cylinder 2. The padded carrier 4 has a sliding pad 3 in both length and width.
Greasing members 5, 5 in the form of rectangular sheets made of an elastic material such as rubber are located on both left and right sides of the pad carrier 4, and there is a gap 6 between the pad carrier 4 and the slide pad 3. ,6
It is attached by screws (not shown) in a state in which a is formed.

The grease stopper members 5, 5 are attached to the pad carrier 4 in such a manner that the upper ends are in elastic contact with the inner surface of the outer cylinder, and the front and rear sides protrude to both the front and rear sides of the pad carrier 4, and when the boom is extended or retracted, the grease stop members 5 , 5 restrict the grease from escaping to the side.

The effect of this point will be explained next.

The grease applied to the upper surface of the slide pad 3 adheres to the inner surface of the outer cylinder due to the boom extension and contraction operation after application. At this time, the inner cylinder 2 expands and contracts slightly downward due to its own weight, and the slide pad 3 is strongly pressed against the inner surface of the outer cylinder.
As shown in the figure, the grease G adheres to the inner surface of the outer cylinder while being pushed to both the left and right sides. Therefore, if left as is, most of the grease G will come off the path of movement of the slide pad 3, and the grease will run out in a short period of time.

In this case, in this device, the grease stopping members 5, 5 function as a dam for the grease G that tries to escape to both the left and right sides of the pad due to the grease pushing action of the slide pad 3, and the grease G
The escape of grease is restricted to the inside of the grease stopper members 5, 5. As a result, the displaced grease G
is accumulated in the gaps 6, 6 between the slide pad 3 and the grease stopper members 5, 5.

In this way, the grease G is always accumulated on both sides of the slide pad 3, so (a) the wall of the accumulated grease G acts as a barrier to prevent the grease from moving due to the subsequent displacement action, and the grease escaping from the top surface of the slide pad (b) The accumulated grease G is compressed by vibrations etc. when the boom is extended and retracted, and as shown by the arrow in Figure 5,
By overflowing from the gap 6 and entering (recovering) the upper surface of the pad, the lubricated state of the sliding part can be reliably maintained for a long period of time. Therefore, it is possible to prevent the occurrence of hunting when the boom is extended and retracted due to running out of grease, and the grease replenishment cycle can be extended, which is advantageous in terms of maintenance.

Also, there is a small amount of
Sheet-shaped grease stopper members 5, 5 with a gap 6 in between.
Since the structure is simply provided in parallel, the space required around the pad is much smaller than the conventional structure in which two pairs of dogleg-shaped scrapers are provided on both sides of the pad. Therefore, there are almost no restrictions on the mounting position of the slide pad 3, and the pad 3 is placed in the optimal position to perform its original function, that is, as close to the proximal end of the inner cylinder 2 as possible, and as far as possible in the left-right direction. It becomes possible to install it in the department.

Other Embodiments () In the embodiment shown in Fig. 6, V-shaped notches 3a are provided on both the front and rear sides of the slide pad 3, and the grease stopper 3 prevents grease from escaping to the side when the boom extends and contracts. This notch 3 not only suppresses grease but also actively removes grease.
I am trying to introduce it to a and 3a and store it. With this configuration, the effect of collecting grease on the upper surface of the slide pad will be even higher.

() On the other hand, the embodiment shown in FIG. 7 goes one step further by providing a vertical wall 7 in front of the pad carrier 4 on the outside of the upper surface of the inner cylinder 2, thereby connecting the vertical wall 7, the pad carrier 4, and the slide pad 3. A grease reservoir 8 is formed in between to more actively collect grease from the upper surface of the pad. In addition,
The vertical wall 7 may be formed by extending the front end of the pad carrier 4 as shown, or may be formed by attaching a separate member to the inner cylinder 2. Further, a grease nipple (not shown) for supplying grease to the grease reservoir 8 from the outside may be provided in the outer cylinder 1.

() Slide pad 3 when extending and retracting the boom
Since the pushing away action is also performed on the front surface of the slide pad 3 in the direction of expansion and contraction, it is desirable to provide the grease stopper members 5, 5 so as to protrude from both the front and rear sides of the slide pad 3 as in the above embodiment. Even if you don't want it to stand out,
A sufficient effect can be achieved because the grease stopper members 5, 5 can resist the pushing away action on both sides of the pad.

() Also, the grease stopper members 5, 5 must be provided in such a way that a gap is formed between them and the slide pad 3 for collecting grease.
This gap does not necessarily need to be formed at the time of installation of the members 5, 5, and may be formed by elastic deformation of the grease stopper members 5, 5 when the boom is extended and retracted. In this way, the space that must be secured on both the left and right sides of the pad for the grease stopper members 5, 5 can be made smaller, and the restrictions on the pad mounting position can be further relaxed.

() In the above embodiment, the case where the slide pad is installed on the outer side of the upper surface of the base end of the inner cylinder is explained as an example, but the above example also applies when the slide pad is installed on the outside of the side surface of the base end of the inner cylinder or on the side of the outer cylinder. It can be implemented similarly.

[Effect of idea]

As described above, according to the present invention, in a telescopic boom in which a slide pad is provided on the sliding surface of either one of the outer cylinder and the inner cylinder that are fitted together so as to be relatively slidable, the boom extension and contraction direction of the slide pad is A grease stopper is installed on the side in a direction perpendicular to the pad, which acts as a dam for grease that is pushed aside by the slide pad when the boom extends and retracts. The displaced grease can be efficiently collected on the slide pad while restricting the escape of the grease. In addition, the mounting positions of the slide pad on the front, rear, left, and right sides are hardly restricted by this grease stopper, so it is possible to install the slide pad in the optimal position to fulfill its original sliding resistance reduction function. Become.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing a sliding device according to a basic embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view taken along the line of FIG. 1, FIG. A partially enlarged plan view for explaining the operation of the device,
5 is a sectional view taken along the line of FIG. 4, FIG. 6 is a view corresponding to FIG. 2 showing another embodiment of the present invention, and FIG. 7 is a longitudinal sectional view showing yet another embodiment. B...Telescopic boom, 1...Outer cylinder constituting the telescopic boom, 2...The same cylinder, 3...Slide pad,
4... Pad carrier, 5, 5... Grease stopper member, 6, 6... Space between the same member and slide pad, G... Grease.

Claims (1)

[Scope of utility model registration request] A slide pad that slides into contact with the other sliding surface is provided on the sliding surface of one of the outer cylinder and the inner cylinder that are relatively slidably fitted together to constitute the telescopic boom. A state in which a grease stopper member made of an elastic body is formed on the side of the sliding surface in the direction perpendicular to the direction of boom extension and contraction of the slide pad, and a gap is formed between the slide pad and the other sliding surface. A sliding device for a telescopic boom, characterized in that it is provided with: