JPH08284211A - Work vehicle - Google Patents

Abstract

PURPOSE: To absorb and alleviate a large impact load transmitted across an upper body and a counterweight. CONSTITUTION: A cylindrical return rubber section 30 is internally provided with a cylinder section for a piston rod 38 to shear a viscous material for expansion and contraction. The piston rod 38 and the section 30 are jointed to each other, thereby forming a vibration absorber 26. Then, a counterweight 19 is mounted on an upper body via the absorber 26 for absorbing a large impact load.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to work vehicles such as hydraulic excavators and mobile cranes.

[0002]

2. Description of the Related Art As a work vehicle, an upper vehicle body is rotatably attached to a lower vehicle body provided with a traveling body, and a bucket type excavating work machine is vertically swingably attached to the upper vehicle body. A hydraulic excavator equipped with an engine and the like is known.

In such a hydraulic excavator, a counterweight is attached to the upper vehicle body on the side opposite to the bucket type excavator to keep the vehicle body balance during excavation work, and shock and vibration are generated during excavation work and traveling. When it is transmitted from the upper body to the counterweight, the heavy counterweight starts to vibrate due to inertial force, and the vibration is transmitted to the entire hydraulic excavator via the upper body, which in turn amplifies the vibration of the entire hydraulic excavator. is there.

To this end, for example, Japanese Unexamined Patent Publication No. 6-11698
As shown in Japanese Patent Publication No. 1, a counterweight is attached to the upper vehicle body through a vibration buffer so that the vibration of the counterweight can be reduced at an early stage.

[0005]

SUMMARY OF THE INVENTION The above-mentioned vibration damper is
As shown in FIG. 1, a closed container 1 having a bottomed cylindrical shape and containing a liquid enclosed therein, a rod 3 protruding from the closed container 1 via a vibration-proof rubber 2, and a rod 3 provided on the rod 3. It is composed of a buffer plate 5 forming a liquid immersion throttle passage 4 enclosed in a closed container 1, the rod 3 of which is connected to a counterweight 6, and the closed container 1 is connected to a mounting portion 7 on the upper vehicle body side. .

With such a vibration absorbing body, when the counterweight 6 is vertically displaced relative to the mounting portion 7 on the upper vehicle body side, the cushioning plate 5 is displaced up and down in the closed container 1 so that the liquid Is caused to flow through the throttle passage 4, a damping force is generated, and the vibration of the counterweight 6 is buffered.

However, with the above-described structure, the maximum vertical stroke of the rod 3 relative to the closed container 1 is restricted by the crushing margin of the flange portion 2a of the vibration-proof rubber 2, and the maximum vertical stroke is small and a large buffer energy is required. It is impossible to absorb.

On the other hand, when a hydraulic excavator or the like falls on a large obstacle such as a boulder during work and then falls and lands or falls into a large depression, a large impact load acts. Even if a weight is attached, a large impact load due to the weight of the counterweight cannot be absorbed and relaxed.

Therefore, an object of the present invention is to provide a work vehicle capable of solving the above-mentioned problems.

[0010]

In a work vehicle in which an upper vehicle body 12 is attached to a lower vehicle body 11 equipped with a traveling body 10, and a work machine, a cab 17, an engine 18, and a counterweight 19 are attached to the upper vehicle body 12, The upper vehicle body 12 is provided with a counterweight 19, a cylindrical return rubber portion 30 and a cylinder portion 31 provided inside thereof, which a piston rod 38 expands and contracts while shearing the viscous body 36, and the piston rod 38 of the cylinder portion 31 is provided. The work vehicle is characterized in that it is attached via a vibration damping body 26 to which a cylindrical return rubber portion 30 is connected.

[0011]

[Operation] The impact load of the counterweight 19 is absorbed by the spring force due to the elastic deformation of the tubular return rubber portion 30 and the resistance force received from the viscous body 36 when the piston rod 38 of the cylinder portion 31 slides.

[0012]

[Examples] As shown in FIG. 2, an upper vehicle body 12 is rotatably attached to a lower vehicle body 11 equipped with a traveling body 10,
A boom 13 of a bucket type excavator 16 including a boom 13, an arm 14, a bucket 15 and the like on the upper body 12.
Is mounted so as to be vertically swingable, and a driver's cab 17, an engine 18, and a counterweight 19 are mounted on the upper vehicle body 12, and the engine 18 is surrounded by a cover body 20.

As shown in FIG. 3, the upper vehicle body 12 has a main frame portion 23 in which a pair of left and right vertical frames 21, 21 are connected by a plurality of connecting members 22, and left frame portions mounted on both sides of the main frame portion 23. 2, a boom 13 shown in FIG. 2 is pivotally attached to a pin hole 28 near the front end of the main frame part 23, and the rear end parts of the left and right vertical frames 21 forming the main frame part 23. 2, a counterweight 19 is attached via a vibration damper 26, a bracket 27 fixed to an intermediate portion of the main frame portion 23 is attached with the engine 18 shown in FIG. 2, and a right frame portion 25 is attached with a driver's cab 17 shown in FIG. Is attached.

As shown in FIG. 4, the vibration buffer 26 is
A cylindrical return rubber portion 30 and a cylinder portion 31 are provided.
The tubular return rubber part 30 is a tubular body integrally formed by alternately stacking a plurality of annular return rubbers 32 and a plurality of annular restraining plates 33 and vulcanizing and adhering them.

The lowermost portion of the cylindrical return rubber portion 30 is an annular restraint plate 33, and the annular restraint plate 33 has a fixed plate 34.
The lower metal fitting 35 is in contact with the lower surface of the fixing plate 34, and the outer peripheral edge portion 35a of the lower metal fitting 35 is fixed to the annular restraining plate 33 by caulking, so that the fixing plate 34 and the lower metal fitting 35 form a cylinder. It is attached to the lowermost part of the return rubber part 30 in the shape of a circle.

In the cylinder portion 31, a piston rod 38 is slidably fitted in a cylinder tube 37 in which a viscous body 36 such as high-viscosity silicon rubber is sealed, and a piston 39 is provided on the piston rod 38, and the piston 39 is provided. An annular gap 40 is formed between the inner wall of the cylinder tube 37 and the inner wall of the cylinder tube 37.

The cylinder portion 31 is a cylindrical return rubber portion 3.
0, the bottom portion 37a of the cylinder tube 37 is in contact with the fixing plate 34, and the lower mounting bolt 41 is provided from the inside of the cylinder tube 37 with the bottom portion 37a, the fixing plate 34, and the lower metal fitting 3
5, the piston rod 38 is integrally provided with an upper mounting bolt 42, and the upper mounting bolt 42 projects upward from the through hole 44 of the upper metal fitting 43, 43 is vulcanized and fixed to the upper surface of the uppermost annular return rubber 32 so that the tip end portion of the piston rod 38 and the upper end portion of the tubular return rubber portion 30 are connected to each other so that they both move up and down at the same time. Come to do.

A concave portion 45 having a size facing the rear end of the vertical frame 21 is formed near the lower front surface of the counterweight 19, and an upper mounting bolt 42 is inserted through a mounting plate 46 fixed to the concave portion 45 to form a nut. Tighten 47 and upper bracket 43
Is attached to the recess 45 of the counterweight 19 via the mounting plate 46.
The lower fitting 35 is in contact with the upper surface of the vertical frame 21, and the lower mounting bolt 41 is connected to the upper horizontal piece 21a of the vertical frame 21.
And the nut 48 is tightened to connect the lower metal fitting 35 to the vertical frame 21.

Next, the operation will be described. When the hydraulic excavator travels or excavates, when the rear part of the traveling body 10 is suddenly landed after being lifted, the lower vehicle body 11 and the upper vehicle body 12 also receive a sudden reaction force from the ground, and a large impact load is applied.

At this time, since the counterweight 19 moves downward due to the inertial force, the piston rod 38 and the piston 39 which are integrated with the upper mounting bolt 42 also push down the viscous body 36 and descend, and at the same time, the tubular return rubber portion 30. Also elastically deforms.

The inertial energy (impact load) of the counterweight 19 is absorbed by the resistance force of the viscous body 36 and the spring force due to the elastic deformation of the tubular return rubber portion 30, and an excessive impact force on the upper vehicle body 12 is absorbed. Reduce.

The elastic restoring force of the cylindrical return rubber portion 30 causes the piston rod 38 and the piston 39 to return to their initial positions, and the viscous body also returns to its original state.

In the above embodiment, the engine 18 is mounted on the bracket 27 via a usual rubber mount, but as shown in FIG. 5, the engine 18 may be mounted on the bracket 27 via the vibration buffer 26 described above. .

That is, as shown in FIG. 5, the upper bracket 43 of the vibration damper 26 shown in FIG. 4 is connected to the mounting bracket 50 of the engine 18, and the lower bracket 35 is connected to the bracket 27.

FIG. 6 shows a third embodiment, in which a mounting base 51 is mounted near the rear portion of the main frame portion 23 of the upper vehicle body 12 through a plurality of vibration buffers 26, and the engine 18 is mounted on the mounting base 51. A counterweight 19 is attached.

By doing so, the engine 18 and the counterweight 19 having different weights are simultaneously displaced relative to the upper vehicle body 12 in the vertical direction together with the mounting base 51, so that the impact force can be efficiently absorbed.

[0027]

The impact load transmitted between the upper vehicle body 12 and the counterweight 19 can be absorbed and relaxed. Since the cylinder portion 31 is provided in the tubular return rubber portion 30 to form the vibration damping body 26, the whole does not become long even if the vertical displacement amount is increased. Therefore, the maximum vertical stroke of the vibration damping body 26 is large, A large impact load transmitted between the upper vehicle body 12 and the counterweight 19 can be absorbed and relaxed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a conventional example.

FIG. 2 is a front view of a hydraulic excavator.

FIG. 3 is a perspective view of an upper vehicle body.

FIG. 4 is a cross-sectional view of a counterweight mounting portion of the present invention.

FIG. 5 is a front view showing an engine mounting portion of the present invention.

FIG. 6 is a front view of an engine and counterweight mounting portion showing a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Running body 11 ... Lower body 12 ... Upper body 17 ... Driver's cab 18 ... Engine 19 ... Counterweight 26 ... Vibration buffer 30 ... Cylindrical return rubber part 31 ... Cylinder part 32 ... Annular return rubber 33 ... Annular restraint plate 35 ... Lower metal fitting 36 ... Viscous body 37 ... Cylinder tube 38 ... Piston rod 39 ... Piston 40 ... Gap 43 ... Upper metal fitting 51 ... Mounting base

Claims (4)

[Claims] 1. A working vehicle in which an upper vehicle body 12 is attached to a lower vehicle body 11 having a traveling body 10, and a working machine, a driver's cab 17, an engine 18, and a counterweight 19 are attached to the upper vehicle body 12, wherein the upper vehicle body 12 A counterweight 19, a cylindrical return rubber portion 30, and a piston rod 38 provided therein.
Is equipped with a cylinder portion 31 that expands and contracts while shearing the viscous body 36, and the piston rod 38 of the cylinder portion 31 and the cylindrical return rubber portion 30 are attached via a vibration cushioning body 26 connected thereto. Work vehicle. 2. The work vehicle according to claim 1, wherein the engine 18 is attached to the upper vehicle body 12 via the vibration buffer 26. 3. An upper vehicle body 12 is attached to a lower vehicle body 11 having a traveling body 10, a working machine and a cab 17 are attached to the upper vehicle body 12, and a mounting base 51 is attached to the upper vehicle body 12.
Is provided with a cylindrical return rubber part 30 and a cylinder part 31 provided inside thereof, in which a piston rod 38 expands and contracts while shearing the viscous body 36, and the piston rod 38 is connected to the cylindrical return rubber part 30 to prevent A work vehicle in which the engine 18 and the counterweight 19 are attached to the attachment base 51 via the vibration damper 26. 4. A plurality of annular return rubbers 32 and a plurality of annular restraint plates 33 are alternately stacked and vulcanized and bonded to form a tubular return rubber portion 30, and a lower metal fitting 35 is provided under the return rubber portion 30.
In addition to mounting the upper metal fitting 43 on the upper part, the piston rod 38 is slidably inserted into the cylinder tube 37 enclosing the viscous body 36, and the piston 39 provided on the piston rod 38 and the inner wall of the cylinder tube 37 are An annular gap 40 is formed between the two to form a cylinder portion 31, and the cylinder portion 31 is provided in the cylindrical return rubber portion 30 to connect the piston rod 38 to the upper fitting 42 to form the vibration damping body 26. The work vehicle according to item 1 or 2 or 3.