JPH06264467A - Working machine support device for bulldozer - Google Patents

Abstract

PURPOSE:To suppress the generation of vibration of a car body during a work and during running by forming the dynamic vibration absorber of a vehicle body such that an accumulator is connected to the head port of the shift cylinder of each of a bulldozer working machine and a ripper working machine. CONSTITUTION:Solenoid switching valves 17 and 18 are respectively arranged to circuits 13', 14' and 15', 16' branched from circuits 13, 14, 15, and 16 through which working oil is fed to lift cylinders 4 and 5. A check valve 19 and an orifice 20 are arranged in parallel in a position situated downstream therefrom and one on the downstream side is coupled to accumulators 6 and 7. When two vehicle bodies 1 are run and a bulldozer working machine 2 and a ripper working machine 3 are both not worked, the switching valves 17 and 18 are switched to an ON-position by means of electric signals 22 and 23 from a controller 21. The working machines 2 and 3 are both vertically excited owing to vibration from a road and head ports 4a and 5a connected to the accumulators 6 and 7 are caused to perform spring operation, and the orifice 20 is caused to perform damping operation by effecting resistance against the passage of oil during expansion and contraction of the cylinders 4 and 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction machine support device for a construction vehicle, in which the construction machine device acts as a vibration absorber to suppress vehicle body vibrations during traveling and at work, and more particularly to a bulldozer. The work machine support device of the.

[0002]

2. Description of the Related Art For example, in a bulldozer as shown in FIG. 11, a dozer working machine 2 is mounted on a front part of a vehicle body 1 via a track frame 1a, and a ripper working machine 3 is mounted on a rear part thereof. Is installed. The hydraulic pump 9 driven by the engine 8 introduces the oil from the hydraulic oil tank 10 into the control valve 11 for the dozer working machine and the control valve 12 for the ripper working machine, and these respective valves 11, 1
Oil is supplied to the blower drift cylinder 4 and the ripper lift cylinder 5 from 2, respectively, and they are operated to rotate the working machines 2 and 3 with pins 31 and 32 as fulcrums.

Therefore, FIG. 1 is a schematic diagram showing the above configuration.
As shown in 2. Here, M is the mass of the entire vehicle, K is the spring constant of the entire vehicle, F is the impact force when the entire conventional vehicle collides with the ground at a certain speed, c1 is the damping coefficient of the entire vehicle spring system, x1 is the entire vehicle. Vertical vibration displacement, u: Vertical displacement of vibration applied to the vehicle body due to unevenness of the ground. As can be seen from heretofore, nothing is provided between the working machines 2 and 3 and the vehicle body 1 as a vehicle body vibration suppressing mechanism during running or working.

[0004]

However, Bulld-
In this case, since the impact load during work is large, the vibration becomes large and the durability is inferior, so in order to secure durability, it is necessary to strengthen each part such as the suspension and inevitably the weight. Has the drawback of becoming heavy and costly.

In view of the above, the present invention provides a working machine support device for a bulldozer, which allows the working machine to act as a dynamic vibration absorber and suppresses vibration of the vehicle body during working and traveling, and has the prior art. The purpose is to eliminate the drawbacks.

[0006]

In order to achieve the above object, the first aspect of the present invention is to provide a dozer working machine at the front of the vehicle body.
In a work machine support device of a bulldozer equipped with a ripper work machine at the rear part, an accumulator is connected to each lift port of the dresser work machine and each head port of the lifter work machine. And a dynamic vibration reducer of the vehicle body is configured,
In the above, the accu
The spring constant of the mullet and the damping coefficient of the orifice on the upstream side of the accumulator are selected so as to minimize the vibration transmissibility to the vehicle body.

[0007]

According to the above construction, in claim 1, the vibration of the working machine is absorbed by the accumulator, and in claim 2, the spring constant of the accumulator and the upstream side of the accumulator. By selecting a predetermined value for the damping coefficient of the orifice, the vibration transmissibility to the vehicle body can be minimized.

[0008]

1 is a hydraulic circuit diagram including a side surface of a bulldozer showing an embodiment of a working machine supporting device for a bulldozer according to claim 1 of the present invention, and FIG. 2 is a hydraulic circuit diagram of the bulldozer of FIG. FIG. 3 is a running posture diagram, FIG. 3 is a state diagram of the bulldozer shown in FIG. 1 during a dozing work, FIG. 4 is a state diagram of the bulldozer shown in FIG. 1 during a ripping work, and FIG. 5 is a model diagram of the configuration of the present invention. FIG. 6 is a graph showing the vibration waveform image of the present invention and the conventional one, FIG. 7 is a graph showing the relationship between the frequency ratio and the vibration transmissibility of the present invention, and FIG. 8 is the rock riding state of the bulldozer of FIG. FIGS. 9 and 9 show the rock climbing / falling state of the bulldozer shown in FIG. 1. (a) is on the verge of falling, (b) is during falling, and FIG. 10 shows the relationship between the soft mount weight ratio of the present invention and the buffer ratio. It is a graph shown.

According to claim 1 of the present invention, as shown in FIG. 1 (the same parts as in FIG. 11 have the same reference numerals as in FIG. 11), a dozer working machine 2 is provided at the front of the vehicle body 1 and a ripper working machine is provided at the rear. In a work machine supporting device for a bulldozer, each of which is provided with a lift cylinder 3, a lift cylinder 4 of the dresser work machine 2 and head heads 4a and 5a of a lift cylinder 5 of the ripper work machine 3 are respectively accumulators. A dynamic vibration absorber of the vehicle body 1 is configured by connecting 6, 7 and claim 2 is an accumulator for supporting the working machines 2, 3 to the vehicle body 1 in claim 1.
The spring constant k of the actuators 6 and 7 and the damping coefficient c2 of the orifice on the upstream side of the accumulator are selected so as to minimize the vibration transmissibility T to the vehicle body 1.

To operate the dozer working machine 2 and the ripper working machine 3, there is a hydraulic pump 9 driven by an engine 8 and the oil sucked from a hydraulic oil tank 10 is drained.
The control valve 11 for the working machine and the control valve 12 for the ripper working machine are led to the respective valves 11, 1.
In operation 2, any of the circuits 13 and 14 supplied to the respective lift cylinders 4 and 5 and 15, 16
However, in the present invention, the circuits 13 and 1 are used.
4, 15 and 16 to circuits 13 ', 14' and 1 respectively
5'and 16 'are respectively branched to branch circuits 13' and 14 ', and 15' and 16 'to turn ON and OF, respectively.
Electromagnetic switching valves (or hydraulic pilot type) 17 and 18 having the F2 position are provided, a check valve 19 and an orifice 20 are arranged in parallel downstream of each of them, and one of the downstreams thereof is connected to the accumulator 6 , 7 and the other is made to flow to the tanks 10, 10. In the figure, reference numeral 21 designates a controller, and a signal i input to the controller 21 is detected by the traveling ON-OFF, whether or not dozing work is being performed, whether or not ripping work is being performed, and the like. . 22 and 23 are electric signals emitted from the controller 21.

Next, the operation will be described. First, when the working machines 2 and 3 are traveling while being separated from the ground as shown in FIG. 2, the dozer working machine 2 and the ripper working machine 3 are not working together. Therefore, the electromagnetic switching valves 17 and 18 are switched to the ON position by the electric signals 22 and 23 from the controller 21. In this state, both the dozer work machine 2 and the ripper work machine 3 are vertically vibrated against vibrations from the road surface, but the head ports 4a, 5a of the cylinders 4, 5 are accumulated. -Because they are respectively connected to the switches 6 and 7, they act as springs. Further, each orifice 20 has a damping action by showing resistance to the passage of oil when the cylinders 4 and 5 expand and contract. Also,
Figure 3 shows the dozing work.
Since the working machine 2 is used, the electromagnetic switching valve 17 does not operate and only 18 is switched to the ON position, but the effects are the same as described above. Similarly, FIG. 4 shows the time of ripping work. At this time, since the ripper working machine 3 is used, the electromagnetic switching valve 18 does not operate, and only 17 is switched to the ON position, and the mass of the dynamic vibration reducer is changed. Next, it acts as a vibration suppressor as described above. This applies to the vibration analysis handled in the two-degree-of-freedom system schematically shown in FIG.
Vehicle vibration displacement x determined by the conventional 1-DOF system shown in 2
A small x1 can be obtained by appropriately setting k and c2 with respect to 1. Here, the explanation of the symbols other than those shown in FIG. 12 is shown below. x2: Vertical displacement of the entire working machine (average value of the dozer working machine and ripper working machine) F1: Impact force when the entire vehicle of the present invention collides with the ground at a certain speed m1: M-m2 = vehicle body Mass m2: Total mass of working machine (dozer working machine + ripper working machine) c2: Attenuation coefficient of orifice in front of accumulator umax: Maximum vertical displacement of vibration applied to vehicle body due to unevenness of ground k: Accumulator spring constant

Next, the operating principle of the dynamic vibration absorber will be described with reference to the vibration model of the two-degree-of-freedom system shown in FIG. 5 while comparing it with the conventional vibration model shown in FIG. In FIG. 12, the equation of motion relating to the forced vibration in which the vibration model moves on the uneven ground that is periodically displaced, Mx1 ″ + c1 (x
1'-u ') + K (x1 -u) = 0 is set and the solution is obtained. X1 = a1 cos {ωt-φ1)}, u = a0
cos ωt. Where a1 is the amplitude of x1 and a0 is u
, Ω is the circular frequency, and φ1 is the phase. Also, a1
= A0 √ {K2 + (c1 ω) 2} / √ {(K-Mω) 2
+ (C1 ω) 2}, tan δ = c1 ω / (k-Mω2
), Tan .alpha. =-C1 .omega. / K.

On the other hand, when the vibration model of the two-degree-of-freedom system according to the present invention shown in FIG. 5 moves on an uneven ground surface which is periodically displaced, the vibration model shown in FIGS. (C)
It will be as shown in. That is, as shown in FIG. 6A, the vertical displacement due to the forced vibration due to the unevenness of the ground is u = a.
0 cos ωt, the vehicle body 1 for the forced vibration
The vertical displacement x1 of x1 is x1 = a as shown in FIG. 6 (b).
It is represented by 1 cos (ωt-φ1), and the vertical displacement x2 of the working machines 2 and 3 is x2 = a1 co as shown in FIG. 6 (c).
It is represented by s (ωt-φ2). Where φ 2 −φ 1 = π,
Alternatively, by designing to be a value close to this, the signs of x1 and x2 are opposite to each other, so the vertical displacement of the vehicle body 1 in consideration of the vertical displacement: x2 of the working machines 2 and 3: x1 ' X1 'as shown in FIG. 6 (b).
= A1'cos (.omega.t-.phi.1), and it can be seen that the amplitude of the vehicle body 1 due to vibration is reduced from a1 to a1 ', as compared with the conventional technique which does not consider the vertical displacement of the working machines 2,3.

Further, the vibration transmissibility T to the vehicle body 1 (driver's cab) by the dynamic vibration absorber constructed by supporting the dozer and ripper working machines 2 and 3 shown in FIG. 1 on the vehicle body 1 is generally. It is expressed as follows. Vibration transmissibility T = x1 / umax = √ [{(α2-p2) 2
+ (2ζαp) 2} / [{(α2-p2) (1-p2)
-Α2 p2 μ} 2 + (2ζαp) 2 (1-p2-p2
μ) 2}] where the symbols in the above equation are as follows. α: Natural frequency ratio (= ω2 / ω1) ω1: Natural frequency of main system (vehicle body) ω2: Natural frequency of secondary system (dynamic vibration absorber by working machine) p: Frequency ratio (= ω2 / ω1) ): Ω: Vibration frequency from the vehicle body μ: Mass ratio (= m2 / m1) ζ: Damping ratio [= c2 / {2√ (m2 / k)}] In the equation showing the vibration transmissibility T, α (= Ω2 / ω1
) Is represented by ω 2 = √ (k / m 2), so α = √ (k
/ M2) / ω1. Since m2 is a constant determined by the shape and strength of the working machine, α = f (k) for a certain ω1. Further, μ (= m2 / m1) is a constant determined by the mass of the working machine and the vehicle body, and ζ [= c
2 / {2√ (m2 / k)}] is the same as the above, = f (c2,
k). Therefore, assuming that the working machine is supported on the vehicle body 1 by an accumulator having a spring constant of k, T = f (k) after all when the damping coefficient c2 of the orifice 20 is substantially constant. . Therefore, in claim 2, the spring constant of the accumulator that minimizes the vibration transmissibility T: k
Then, as shown in FIG. 7, the vibration transmissibility T can be lowered and the riding comfort can be improved.

Further, as shown in FIG. 8, assuming that the impact load applied to the undercarriage at the time of climbing over the rock when climbing on the rock and falling is F, the respective working machines 2, 3 are accumulators 6, 7. Kinetic energy equivalent to the weight of work machines 2 and 3
Is absorbed, and the shock load F1 has a buffering effect that it becomes small. The amount is determined by the weight ratio of the working machines 2 and 3 to the vehicle body 1 and the spring constant, but when calculated by the bulldozer according to the present invention, it is about 87% when the conventional one is 100%. It can be seen that the impact load is reduced to%. As a result, it is possible to improve the durability of each part of the vehicle body including the suspension and improve the ride comfort of the operator.

[0016]

As described above, according to claim 1 of the present invention, there is provided a working apparatus supporting device for a bulldozer, comprising a dozer working machine at a front portion of a vehicle body and a ripper working machine at a rear portion thereof. A lift cylinder of the dresser working machine, and an accumulator is connected to each head port of the lift cylinder of the ripper working machine to form a dynamic vibration reducer of the vehicle body.
According to a second aspect of the present invention, the spring constant of the accumulator supporting each of the working machines in the vehicle body and the damping coefficient of the orifice on the upstream side of the accumulator are the vibration transmission to the vehicle body. Since the selection is made to minimize the ratio, the durability of each part such as the undercarriage device is improved by reducing the load on the undercarriage, or the cost is reduced by reducing the weight and the dynamic vibration absorption function Since the vehicle body vibration (swing) due to the vibration can be suppressed, the ride comfort of the operator can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory view of a hydraulic circuit including a side surface of a bulldozer, showing an embodiment of a working machine support device for a bulldozer according to claim 1 of the present invention.

FIG. 2 is an explanatory diagram showing a traveling posture of the bulldozer shown in FIG.

FIG. 3 is an explanatory view of the bulldozer shown in FIG. 1 during a dosing operation.

4 is an explanatory view of a state of the bulldozer shown in FIG. 1 during a ripping operation.

FIG. 5 is an explanatory diagram of a model of the configuration of the present invention.

FIG. 6 is an explanatory diagram with a graph showing a vibration waveform image of the present invention and a conventional one.

FIG. 7 is an explanatory diagram with a graph showing the relationship between the frequency ratio and the vibration transmissibility of the present invention.

FIG. 8 is an explanatory diagram showing a rock climbing state of the bulldozer shown in FIG. 1;

9A and 9B show a state in which the bulldozer of FIG. 1 falls over a rock, in which FIG. 9A is a drawing on the verge of falling and FIG.

FIG. 10 is an explanatory diagram with a graph showing the relationship between the soft mount weight ratio and the buffer rate of the present invention.

FIG. 11 is an explanatory view of a hydraulic circuit including a side surface of a bulldozer, showing an embodiment of a conventional work implement supporting device for a bulldozer.

FIG. 12 is an explanatory diagram of a model having a conventional configuration.

[Explanation of symbols]

 1 vehicle body 2 dozer working machine 3 ripper working machine 4,5 lift cylinders 4a, 5a head port 6,7 accumulator k spring constant c2 damping coefficient T vibration transmissibility

Claims (2)

[Claims] 1. A working machine support device for a bulldozer, comprising a dozer working machine at a front portion of a vehicle body and a ripper working machine at a rear portion thereof, and a lift cylinder of the dozer working machine,
A work machine support device for a bulldozer, characterized in that an accumulator is connected to each head port of a lift cylinder of the ripper work machine to form a dynamic vibration absorber of the vehicle body. 2. The spring constant of an accumulator that supports each of the working machines on the vehicle body and the damping coefficient of the orifice on the upstream side of the accumulator have a minimum vibration transmissibility to the vehicle body. The working machine support device for the bulldozer according to claim 1, wherein the working machine support device is selected as follows.