JP6772759B2 - Telescopic boom type work machine - Google Patents

Description

The present invention relates to a telescopic boom type working machine including a telescopic boom.

Conventionally, there is known a telescopic boom type working machine in which a plurality of tubular booms are arranged so as to form a nested structure, and the inner boom slides with respect to the outer boom to expand and contract (for example, Patent Document). 1). Generally, in a telescopic boom type work machine, a lubricant (for example, grease) is applied to the gap between the booms adjacent to the inside and outside in order to slide the boom smoothly and to suppress the vibration of the boom during expansion and contraction. The slide plate is placed. If the boom vibrates during expansion and contraction, the hook suspended at the tip will shake and collide with the boom, which is extremely dangerous.

Although the above-mentioned method is adopted as a countermeasure against the vibration of the boom during expansion and contraction, it is difficult to permanently prevent the vibration because the sliding state between the booms changes with time. Conventionally, when vibration occurs, it is dealt with by reapplying grease, changing the type of grease, changing the material of the slide plate, adjusting the backlash of the slide plate, or changing the fixing position of the telescopic wire. There is.

Japanese Unexamined Patent Publication No. 2011-84350

However, the vibration of the boom during expansion and contraction is self-excited vibration based on an aperiodic external force, and it is difficult to identify the cause. Therefore, the above-mentioned measures are largely based on the intuition and experience of the maintenance worker, and the vibration of the boom at the time of expansion and contraction may not be improved, and the maintenance work may take a long time.

An object of the present invention is to provide a telescopic boom type working machine that can suppress the vibration of the boom during expansion and contraction and can easily cope with the vibration of the boom over time.

The telescopic boom type working machine according to one aspect of the present invention is
A telescopic boom having a telescopic structure consisting of a plurality of tubular booms including a base boom and a tip boom,
A dynamic vibration absorber having a spring portion and a mass portion and at least one end of the spring portion being fixed to the telescopic boom is provided .
The dynamic vibration absorber is characterized in that it is arranged inside the telescopic boom .
The telescopic boom type working machine according to one aspect of the present invention is
A telescopic boom having a telescopic structure consisting of a plurality of tubular booms including a base boom and a tip boom,
A dynamic vibration absorber having a spring portion and a mass portion and at least one end of the spring portion being fixed to the telescopic boom is provided.
The spring portion is characterized in that it extends along the boom axis direction.
The telescopic boom type working machine according to one aspect of the present invention is
A telescopic boom having a telescopic structure consisting of a plurality of tubular booms including a base boom and a tip boom,
A dynamic vibration absorber having a spring portion and a mass portion and at least one end of the spring portion being fixed to the telescopic boom is provided.
The dynamic vibration absorber is arranged inside the telescopic boom.
The spring portion is characterized in that it extends along the boom axis direction.

According to the present invention, when a vibration having the same frequency as the natural frequency of the dynamic vibration absorber is generated in the expansion / contraction boom, this vibration is absorbed by the dynamic vibration absorber. Therefore, by adjusting the natural frequency of the dynamic vibration absorber, it is possible to suppress specific vibrations that occur during expansion and contraction in the expansion and contraction boom, and it is easy to deal with the case where the boom vibrations occur over time. can do.

It is a figure which shows the state at the time of running of the telescopic boom type working machine which concerns on one Embodiment of this invention. It is a figure which shows the state at the time of working of the telescopic boom type work machine. It is a figure which shows the dynamic vibration absorber which concerns on embodiment. It is a figure which shows the dynamic vibration absorber which concerns on embodiment. It is a figure which shows the arrangement mode of the dynamic vibration absorber which concerns on a modification. It is a figure which shows the arrangement mode of the dynamic vibration absorber which concerns on a modification. It is a figure which shows another example of a dynamic vibration absorber. It is a figure which shows another example of the arrangement mode of a dynamic vibration absorber. It is a figure which shows an example of the case where the dynamic vibration absorber is attached to the aerial work platform.

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

FIG. 1 is a diagram showing a running state of the telescopic boom type working machine 1 according to the embodiment of the present invention. FIG. 2 is a diagram showing a working state of the telescopic boom type working machine 1. The telescopic boom type working machine 1 shown in FIGS. 1 and 2 is a so-called rough terrain crane, and includes an upper swing body 10 and a lower traveling body 20 (hereinafter referred to as “rough terrain crane 1”). The rough terrain crane 1 is a self-propelled crane that uses tires for the traveling portion of the lower traveling body 20, and can perform traveling operations and crane operations from one cab.

The upper swivel body 10 includes a swivel frame 11, a cabin 12 (cab), a telescopic boom 100, an undulating cylinder 13, a jib 14, a hook 15, a bracket 16, a counterweight (not shown), and a hoisting device (winch, not shown). ) Etc. are provided.

The swivel frame 11 is rotatably supported by the lower traveling body 20 via a swivel support (not shown). A cabin 12, a telescopic boom 100, an undulating cylinder 13, a bracket 16, a counterweight (not shown), a hoisting device (winch, not shown), and the like are attached to the swivel frame 11.

The cabin 12 is arranged at the front of the swivel frame 11. The cabin 12 includes an operation unit including operation levers, handles, pedals, switches, etc. for performing traveling operations (for example, steering of the front wheels 22 and rear wheels 23) and crane operations (for example, undulations and expansion / contraction of the expansion / contraction boom 100), and an operation unit. It has a display unit that includes instruments that display various types of information (all are not shown).

The telescopic boom 100 is rotatably attached to the bracket 16 via a support shaft (foot pin, code omitted). In the telescopic boom 100, the side attached to the bracket 16 is referred to as the "base end side", and the opposite side is referred to as the "tip end side". In the present embodiment, the telescopic boom 100 is a six-stage organization, and has a base end boom 101, intermediate booms 102 to 105, and a tip boom 106 in this order from the base end side when extended. A boom head 107 having a sheave (reference numeral omitted) is arranged at the tip of the tip boom 106. Further, a dynamic vibration absorber 110 (see FIGS. 3 and 4) for suppressing the vibration of the telescopic boom 100 is arranged on the tip surface of the boom head 107.

In the telescopic boom 100, the number of intermediate booms is not particularly limited. Further, a work attachment such as a bucket may be attached to the boom head 107. In the following, when the base end boom 101, the intermediate booms 102 to 105, and the tip end boom 106 are not distinguished, they are referred to as “boom 101 to 106”.

The booms 101 to 106 are formed of, for example, a high-strength steel plate. The booms 101 to 106 have a tubular shape with both ends open in the boom axial direction, and are arranged in a nested manner so that the base end boom 101 is on the outermost side and the tip end boom 106 is on the innermost side. The intermediate booms 102 to 105 and the tip boom 106 expand and contract in the longitudinal direction with respect to the base end boom 101 by expanding and contracting the telescopic cylinders (not shown) arranged inside (so-called telescopic structure). The boom length of the telescopic boom 100 is, for example, 9.8 m in the fully retracted state (hereinafter referred to as “basic boom length”) and 44.0 m in the fully extended state (hereinafter referred to as “maximum boom length”).

The undulating cylinder 13 is erected between the swivel frame 11 and the telescopic boom 100. The expansion and contraction of the undulation cylinder 13 causes the expansion and contraction boom 100 to undulate. The undulation angle of the telescopic boom 100 is, for example, 0 ° to 84 °.

The jib 14 is rotatably attached to the tip of the telescopic boom 100 (boom head 107) when the lift is expanded. The jib 14 projects forward of the telescopic boom 100 by rotating forward.

The hook 15 is a hook-shaped hanger, and has a main winding hook and an auxiliary winding hook. The hook 15 is attached to a wire rope 17 hung around a sheave at the tip of the boom head 107 or the tip of the jib 14. The hook 15 moves up and down as the wire rope 17 is wound or unwound by the hoisting device (not shown).

The lower traveling body 20 includes a vehicle body frame 21, front wheels 22, rear wheels 23 (hereinafter referred to as “wheels 22, 23”), front outriggers 24, rear outriggers 25 (hereinafter referred to as “outriggers 24, 25”), and an engine 26. Etc. are provided.

The driving force of the engine 26 is transmitted to the wheels 22 and 23 via a transmission (not shown). The rough terrain crane 1 travels by rotating the wheels 22 and 23 by the driving force of the engine 26. Further, the steering angles (traveling directions) of the wheels 22 and 23 change with the operation of the steering wheel (not shown) provided in the cabin 12.

The outriggers 24 and 25 are housed in the vehicle body frame 21 during traveling. On the other hand, the outriggers 24 and 25 project in the horizontal and vertical directions during work (when the upper swing body 10 is operated), lift the entire vehicle body, and stabilize the posture.

In the rough terrain crane 1, when expanding and contracting (especially when storing), the telescopic boom 100 vibrates mainly in the direction in which the hook 15 is suspended, in other words, in the plane where the telescopic boom 100 is undulated. (Hereinafter referred to as "pitch"). The present inventors have discovered that if the undulation state (undulation angle) of the expansion / contraction boom 100 at the time of expansion / contraction of the boom is the same, vibration starts to occur at substantially the same boom length. Then, by applying a dynamic vibration absorber to suppress this vibration, and further suppressing the vibration that occurs first when the vibration is stored from the fully extended state, the vibration generated in the telescopic boom 100 can be dramatically reduced. After confirming, I came up with the present invention.

3 and 4 are views showing an example of the dynamic vibration absorber 110 attached to the tip end portion (boom head 107) of the telescopic boom 100. FIG. 4A is a front view seen from the tip side, and FIG. 4B is a vertical sectional view along the boom axis.

As shown in FIGS. 3 and 4, the dynamic vibration absorber 110 has a spring portion 111 and a mass portion 112. The dynamic vibration absorber 110 may have a damping system (not shown). The dynamic vibration absorber 110 is a device that vibrates in place of the main system by adding mass (mass portion 112) to the telescopic boom 100, which is the target vibration system (main system), via the spring portion 111. The dynamic vibration absorber 110 absorbs the vibration of the main system by vibrating the mass portion 112 in the opposite phase to the main system.

The dynamic vibration absorber 110 can absorb the vibration when the expansion / contraction boom 100 vibrates at the same frequency as its own natural frequency. In other words, by adjusting the natural frequency of the dynamic vibration absorber 110, it is possible to absorb the vibration having a specific frequency among the vibrations that can occur in the telescopic boom 100.

Here, in the dynamic vibration absorber 110, the natural frequency is adjusted based on the vibration first generated when the telescopic boom 100 is retracted from the fully extended state in a predetermined undulating state (for example, an undulating angle of 70 °). .. That is, the natural frequency of the dynamic vibration absorber 110 is adjusted so as to match the frequency when the telescopic boom 100 starts to vibrate during storage. As a result, it is possible to suppress the vibration having a long boom length and the largest amplitude (the vibration that is most desired to be suppressed among the vibrations that can occur in the telescopic boom 100). Therefore, the hook 15 suspended from the telescopic boom 100 does not sway and collide with the telescopic boom 100, further improving safety.

Here, the predetermined undulating state is an undulating state in which vibration of the boom is likely to occur when the expansion / contraction boom 100 is expanded / contracted, and is substantially determined for each expansion / contraction boom 100. In other words, when the expansion / contraction boom 100 is expanded / contracted in an undulating state other than the predetermined undulating state, vibration is unlikely to occur. For example, in a certain telescopic boom 100, when the undulation angle is 70 ° to 84 °, vibration starts to occur with substantially the same boom length. That is, the predetermined undulating state is represented by the range of the undulating angle and the range of the boom length when the vibration starts to occur. Since the change in the natural frequency of the telescopic boom 100 at this time is slight, the natural frequency of the dynamic vibration absorber 110 should be adjusted based on the natural frequency that the telescopic boom 100 can take when it is in a predetermined undulating state. Therefore, vibration can be sufficiently suppressed by one dynamic vibration absorber 110.

As for the frequency when the telescopic boom 100 starts to vibrate, the boom length at which the telescopic boom 100 actually starts to vibrate by accommodating the telescopic boom 100 from the fully extended state is specified for a plurality of undulating angles, and this boom length is set. It can be calculated using. Alternatively, a vibration sensor may be attached to the telescopic boom 100 to directly measure the frequency at which the telescopic boom 100 begins to vibrate. As described above, the telescopic boom 100 may not vibrate depending on the undulation angle.

In the present embodiment, the spring portion 111 is a leaf spring having a predetermined length (hereinafter referred to as "leaf spring 111"). The mass portion 112 is a weight having a predetermined weight (hereinafter referred to as “weight 112”). One end of the leaf spring 111 is fixed to the tip surface 107a of the boom head 107 by, for example, bolting. A weight 112 is attached to the other end side of the leaf spring 111. That is, the dynamic vibration absorber 110 is a cantilever type dynamic vibration absorber.

As described above, the dynamic vibration absorber 110 is preferably arranged at the boom tip of the telescopic boom 100. Further, the dynamic vibration absorber 110 is preferably arranged so that the leaf spring 111 extends along the boom axis direction. As a result, it is possible to prevent the dynamic vibration absorber 110 from becoming an obstacle when the telescopic boom 100 is stored and traveled.

The material (elastic modulus) and dimensions (length, width, thickness) of the leaf spring 111, and the mass of the weight 112 are the range of vibration frequencies that can occur in the telescopic boom 100, that is, the telescopic boom 100 is fully extended. When the state is changed from the state to the fully retracted state (or a predetermined boom length), the natural frequency of the telescopic boom 100 is appropriately set according to the range that can be taken.

Further, in the dynamic vibration absorber 110, it is preferable that the leaf spring 111 is arranged so that the plate surface faces the vibration damping direction, that is, the pitching direction. Thereby, the pitching generated in the expansion / contraction boom 100 at the time of expansion / contraction can be efficiently absorbed.

Further, in the present embodiment, the leaf spring 111 has an elongated hole 111a along the longitudinal direction on the plate surface. In FIG. 3, three elongated holes 111a appear out of the four elongated holes 111a. The weight 112 is fixed to the leaf spring 111 by inserting the bolt 113 into the insertion hole 112a of the weight 112 and fastening the bolt 113 to the elongated hole 111a of the leaf spring 111. That is, the weight 112 is movable in the length direction of the leaf spring 111. In FIG. 3, the weight 112 is fixed to the elongated hole 111a located at the most advanced end.

As described above, the dynamic vibration absorber 110 preferably has a structure capable of continuously changing the effective length (length functioning as a spring portion) of the leaf spring 111. As a result, the natural frequency of the dynamic vibration absorber 110 can be easily adjusted. Therefore, when the boom length when vibration occurs in the telescopic boom 100 changes over time, that is, the frequency of vibration generated in the telescopic boom 100. Can be easily dealt with when the value changes over time.

In the case of the telescopic boom 100 having a maximum boom length of 44 m (natural frequency 2.5 Hz) and a basic boom length of 9.8 m, for example, the leaf spring 111 is made of HT590 (longitudinal elastic modulus: 203 GPa) and has a length: The effective length of the spring portion 111 is determined by using a dynamic vibration absorber 110 made of SS400 and having a mass of 4.5 to 15 kg as the weight 112, which is 1175 mm, width: 60 mm, and thickness: 6 mm. By adjusting the thickness to 452 to 786 mm, pitching during expansion and contraction can be remarkably suppressed.

[Modification example]
5 and 6 are views showing an arrangement mode of the dynamic vibration absorber 110 according to the modified example. FIG. 6B is a vertical cross-sectional view along the boom axis, and FIG. 6A is a cross-sectional view seen from the direction of the BB arrow in FIG. 6B. Compared with the configuration shown in the embodiment, the extension direction of the spring portion 111 is opposite, and the other configurations are the same.

As shown in FIGS. 5 and 6, the dynamic vibration absorber 110 may be arranged inside the telescopic boom 100. In the telescopic boom 100, the insides of the tip boom 106 and the boom head 107 are usually hollow. In the modified example, the dynamic vibration absorber 110 is arranged using this space. In the telescopic boom 100 of the modified example, the same outer shape as before is secured. As a result, it is possible to reliably prevent the dynamic vibration absorber 110 from becoming an obstacle when the telescopic boom 100 is stored and traveled.

As described above, the rough terrain crane 1 (expandable boom type working machine) according to the embodiment has a telescopic boom 100 having a telescopic structure including a plurality of tubular booms 101 to 106 including a base end boom 101 and a tip end boom 106. And a dynamic vibration absorber 110 having a spring portion 111 and a mass portion 112, and one end of the spring portion 111 being fixed to the telescopic boom 100.

In the rough terrain crane 1, when a vibration having the same frequency as the natural frequency of the dynamic vibration absorber 110 is generated in the telescopic boom, this vibration is absorbed by the dynamic vibration absorber 110. Therefore, by adjusting the natural frequency of the dynamic vibration absorber 110, it is possible to suppress a specific vibration generated during expansion and contraction in the expansion and contraction boom 100. If the vibration of the expansion / contraction boom 100 cannot be suppressed over time, the natural frequency of the dynamic vibration absorber 110 is readjusted (including adjustment of the effective length of the spring portion 111 / replacement of the dynamic vibration absorber 110). Therefore, it can be easily dealt with.

Furthermore, the number of times the lubricant is applied can be reduced, and the man-hours required for conventional vibration countermeasures can be reduced, and the maintenance work time can be significantly shortened. In addition, vibration countermeasures can be realized by a simple and inexpensive device called a dynamic vibration absorber without adding complicated components.

Although the invention made by the present inventor has been specifically described above based on the embodiment, the present invention is not limited to the above embodiment and can be changed without departing from the gist thereof.

For example, the configuration of the dynamic vibration absorber arranged on the telescopic boom is not limited to that described in the embodiment, and may have a spring portion and a mass portion, and one end of the spring portion is fixed to the telescopic boom. Just do it. Specifically, when the dynamic vibration absorber is arranged inside the telescopic boom, as shown in FIG. 7, a plurality of compression coil springs 121 (spring portions) and a spherical mass portion 122 are combined to float the mass portion 122. A dynamic vibration absorber 120 having a structure in which the vibration absorber 120 is held in the state of being moved can be applied. In this case, since the dynamic vibration absorber 120 exerts a vibration damping action against vibrations in all directions, various vibrations generated in the telescopic boom 100 can be suppressed.

Further, for example, in the case of the cantilever type dynamic vibration absorber 110 described in the embodiment, the spring portion 111 extends along the boom axial direction not only on the tip surface of the telescopic boom 100 but also on the peripheral surface of the telescopic boom 100. It may be arranged so as to (see FIG. 8A). In this case, the booms 101 to 106 can be remarkably attached. FIG. 8A shows an example in which the dynamic vibration absorber 110 is arranged on the upper surface of the intermediate boom 105, the lower surface of the intermediate boom 104, and the side surface of the intermediate boom 102.

Further, for example, in the case of the cantilever type dynamic vibration absorber 110 described in the embodiment, the spring portion 111 may be arranged so as to extend in a direction orthogonal to the boom axis direction of the telescopic boom 100 (FIG. 8B). reference).

Further, in the cantilever type dynamic vibration absorber 110, the spring portion 111 may be formed of a rod-shaped elastic body. In this case, since the vibration damping direction of the dynamic vibration absorber 110 is not limited to the pitching direction, the vibration that may occur in the expansion / contraction boom 100 can be suppressed more effectively.

Further, the number and arrangement of the dynamic vibration absorbers 110 arranged on the telescopic boom 100 are not particularly limited. When a plurality of dynamic vibration absorbers 110 are provided, they may be adjusted so that their natural frequencies are different. This makes it possible to suppress a plurality of vibrations having different frequencies.

The present invention can be applied to a telescopic boom type working machine provided with a telescopic boom, such as an all-terrain crane, a truck crane, or an aerial work platform. In particular, in aerial work platforms with a bucket attached to the tip of the telescopic boom, the telescopic boom expands and contracts with the worker on the bucket, so when the telescopic boom vibrates, the bucket also shakes, reducing workability. There is a risk of By applying the present invention to the aerial work platform, the vibration of the telescopic boom is suppressed, so that it is possible to prevent the bucket from shaking and the workability from being lowered.

In this case, as shown in FIG. 9, the worker OP in the bucket 130 moves the slider 114 of the dynamic vibration absorber 110 up and down along the length direction of the spring portion 111 from the bucket 130, and the spring portion 111. It is preferable that the effective length of the spring portion 111 and the natural frequency of the dynamic vibration absorber 110 can be adjusted by changing the position of the fixed end of the spring portion 111. As a result, even if the telescopic boom 100 vibrates, the worker OP in the bucket 130 can quickly converge the vibration by his own action of moving the slider 114, and the work accompanying the vibration of the telescopic boom 100 can be performed. It is possible to avoid a decrease in sex.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and it is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Rough terrain crane (expandable boom type work machine)
10 Upper swing body 20 Lower traveling body 100 Telescopic boom 101 Base end boom 102 to 105 Intermediate boom 106 Tip boom 107 Boom head 110 Dynamic vibration absorber 111 Leaf spring (spring part)
112 Weight (mass part)

Claims (7)

A telescopic boom having a telescopic structure consisting of a plurality of tubular booms including a base boom and a tip boom,
A dynamic vibration absorber having a spring portion and a mass portion and at least one end of the spring portion being fixed to the telescopic boom is provided .
The dynamic vibration absorber is a telescopic boom type working machine characterized in that it is arranged inside the telescopic boom. A telescopic boom having a telescopic structure consisting of a plurality of tubular booms including a base boom and a tip boom,
A dynamic vibration absorber having a spring portion and a mass portion and at least one end of the spring portion being fixed to the telescopic boom is provided.
A telescopic boom type working machine characterized in that the spring portion extends along the boom axial direction. A telescopic boom having a telescopic structure consisting of a plurality of tubular booms including a base boom and a tip boom,
A dynamic vibration absorber having a spring portion and a mass portion and at least one end of the spring portion being fixed to the telescopic boom is provided.
The dynamic vibration absorber is arranged inside the telescopic boom.
A telescopic boom type working machine characterized in that the spring portion extends along the boom axial direction. The telescopic boom type working machine according to claim 2 or 3, wherein the spring portion is a leaf spring, and the leaf surface is arranged so as to face the direction in which the undulating operation of the telescopic boom is performed. Any of claims 1 to 4, wherein the dynamic vibration absorber has a natural frequency adjusted based on the vibration that is first generated when the dynamic vibration absorber is stored from the fully extended state in a predetermined undulating state. The telescopic boom type work machine described in item 1 . The telescopic boom type working machine according to any one of claims 1 to 5, wherein the dynamic vibration absorber is arranged at the tip of the telescopic boom. The mass portion or the fixed end of the spring portion is movable in the length direction of the spring portion.
Any of claims 1 to 6, wherein the effective length of the spring portion is changed by changing the position of the mass portion in the length direction or the position of the fixed end in the length direction. The telescopic boom type working machine described in item 1.

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