JP2807757B2 - Heavy equipment straight running device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heavy-duty straight traveling device, and more particularly, to a traveling device which is operated by operating a working device while various construction machines such as an excavator and a crane are traveling. The present invention relates to a device capable of maintaining straightness.

[0002]

2. Description of the Related Art Generally, mobile construction machines such as excavators and cranes use a traveling actuator (travel motor) and a working equipment actuator (boom cylinder, arm cylinder, etc.) depending on the amount of oil discharged by the same pump. ) Is configured to be activated.

[0003] Fig. 1 shows a hydraulic circuit of a conventional excavator, but a first hydraulic pump P1 and a second hydraulic pump P1 having the same capacity.
A hydraulic pump P2 is provided so as to be driven by a single engine E. A first hydraulic pump P1 is responsible for supplying hydraulic oil to a swing motor SW, a left traveling motor TL, and an arm cylinder ARM.
Numeral 2 is in charge of supplying hydraulic oil to the boom cylinder BM, the right traveling motor TR, optional devices such as OPT, and the bucket cylinder BKT. The member numbers V1, V2 and V3 are the swing motors S, respectively.
W, left running motor TL and arm cylinder ARM
V4, V5, V6 and V7 denote the switching valves of the boom cylinder BM, the right traveling motor TR, the optional device OPT and the bucket cylinder BKT, and the like.

Considering the hydraulic oil supply line, when the above-mentioned switching valves V1, V2, V3, V4, V5, V6, V7 are all neutral, the first hydraulic pump P1 and the second hydraulic pump P2 respectively Tank T immediately for discharged oil
To return to the center bypass passages 101 and 102
Are provided, and switching valves V1, V2, V3, V4, V5,
At the time of operation of V6 and V7, parallel oil passages 103 and 104 for supplying hydraulic oil to the corresponding actuators in parallel are provided. The member numbers Pi correspond to the switching valves V1, V2, V3, V4, V5, V
6, a pilot pump for providing a spool moving pressure to V7, and reference numerals 105a and 105b indicate left and right traveling motor operated valves, respectively.

[0005]

In the conventional equipment configured as described above, when the engine E is started and the left and right traveling motor operation valves 105a and 105b are operated, the discharge from the first hydraulic pump P1 is performed. Is supplied to the left traveling motor TL through the parallel oil passage 103 and the switching valve V2, and the amount of oil discharged from the second hydraulic pump P2 is transmitted through the parallel oil passage 104 and the switching valve V5.
Supplied to At this time, the first and second hydraulic pumps P
1. Since the capacity of the pump 2 is the same, the equipment can run straight.

However, if at least one of the working devices is operated while the above equipment is running straight, for example, the arm cylinder A
When the operation oil is supplied to the RM to operate the arm, the amount of oil discharged from the first hydraulic pump P1 is distributed and supplied to the left traveling motor TL and the arm cylinder ARM through the parallel oil passage 103. . Therefore, since the amount of oil supplied to the left traveling motor TL is reduced as compared with the right traveling motor TR, there is a problem that the equipment cannot be kept straight and is deflected to the left. Further, when the required pressure of the working device operated at the same time as traveling is higher than the traveling required pressure, for example, at the time of work such as arm-out (ARM-OUT), there is a problem that the work equipment is not operated at all.

Therefore, there is an absolute necessity for a straight traveling device for preventing unexpected deflection of the equipment and maintaining the straightness of traveling even when the working device is operated while the equipment is traveling. Was. In the conventional straight traveling device, when the working device is not operated during traveling, the first and second pumps independently take charge of the hydraulic oil supply to the left traveling motor and the right traveling motor, however, when the working device is activated. , One of the first and second pumps simultaneously serves to supply the hydraulic oil to the left traveling motor and the right traveling motor, and the other one pump supplies the hydraulic oil to the operated working device. Was designed to

However, in the above-described conventional straight traveling device, the left and right traveling motors are operated by the oil amount discharged from one pump during operation of the working device during traveling, so that the traveling speed is suddenly reduced. In addition, the above-described operation is performed even when the operated working device is a working device having a very small required pressure, which is considerably inefficient when viewed from the aspect of oil distribution. There was a side.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a heavy equipment straight traveling device capable of preventing unexpected deflection of the equipment and maintaining traveling straightness even when the work device is operated while the equipment is traveling. It is in.

Another object of the present invention is to enable the working device to be operated even when the required pressure of the working device operated at the same time as the traveling is higher than the required traveling pressure. It is an object of the present invention to provide a heavily-equipped straight traveling device capable of preventing deceleration of the vehicle and achieving efficient oil distribution.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a first and second hydraulic pumps having the same capacity, and a left and right traveling driven by the discharge oil amounts of the first and second hydraulic pumps. in the straight traveling apparatus for heavy construction equipment equipped with a motor and a plurality of working device actuators, the first
1 Left side parallel between the hydraulic pump and the left side traveling motor
An oil passage, the second hydraulic pump, and the right traveling motor;
Are provided in the right parallel oil passage between
First by internal pressure selection according to spool movement
Left and right oil passage switching valves having a state and a second state, and
Merging oil passage provided between the left and right oil passage switching valves
Only the left and right traction motors are activated
The left and right oil passage switching valves are in the first state.
The left and right parallel oil passages and the merged oil passage
And each of the first and second hydraulic pumps
The discharge oil amount of the left and right traveling motors respectively
So that the left and right traction motors are
Be operated and at least one of the working devices
When either one is activated, the left side and
The right oil passage switching valve is in the second state, and the left and right oil passage switching valves are in the second state.
And the junction oil passage is connected to each other,
2 After the discharge oil volume of the hydraulic pump is merged,
This is achieved by providing a heavy equipment straight running device supplied to the left and right running motors .

[0012]

FIG. 2 shows an excavator hydraulic circuit to which a straight traveling device according to one embodiment of the present invention is applied. In describing this embodiment, a detailed description of the general configuration of the excavator hydraulic circuit already described in the related art with reference to FIG. 1 will be omitted, and the same components will be denoted by the same reference numerals. Attached.

As shown in FIG. 2, the left and right traveling paths are respectively disposed in the left traveling motor TL side parallel oil path 1a (left side parallel oil path) and the right traveling motor TR side parallel oil path 1b (right side parallel oil path). Straight valves 2a and 2b are provided. The left and right traveling straight travel valves 2 a and 2 b have the same configuration, and are connected to each other by the merged oil passage 3. The left and right switching valves 2a and 2b are in a first state in which the left and right parallel oil passages 1a and 1b and the junction oil passage 3 are shut off from each other by the internal oil passage selection accompanying the spool movement as shown in FIG. There is a second state in which the left and right parallel oil passages 1a and 1b and the junction oil passage 3 communicate with each other.

In the second state, in the left and right oil passage switching valves (2a and 2b), the internal oil passage (5) connecting the hydraulic pump side parallel oil passage and the traveling motor side parallel oil passage to each other is connected.
Orifices (4a and 4b) are provided in 1a and 51b), respectively. Left and right traveling straight valves (2a
And 2b) are initially set to have a first state by pressure setting springs (5a and 5b), respectively.

The pressure receiving part and the back pressure part of the left and right straight valves (2a and 2b) are a pilot line 6 (first pilot line), a pressure receiving part pilot line 6a branched from the pilot line 6, and a back pressure. The left and right traveling straight valves (2a and 2b) are supplied to the first state I by receiving the pilot oil supplied through the pilot line 6b.
And the second state II. On the other hand, a pilot line 6c (second pilot line) branched from one fulcrum of the back pressure part pilot line 6b is connected to each of the switching valves (V1, V2) except for the traveling systems (TL and TR).
3, V4, V6, V7) and other selector valves (SV1,
After passing through (SV3, SV4, SV6, SV7), it is returned to the tank T through the return line.

These selector valves (SV1, SV3,
SV4, SV6, SV7) are provided with the respective switching valves (V1, V3, V
4, V6, V7) and the like are in the neutral state, the pilot line 6c is cut off, and if operated in any direction,
The oil in the back pressure part pilot line 6b is returned to the tank T by communicating with the pilot line 6c. on the other hand,
In the aforementioned pilot line 6, an orifice 7 is provided between a branch point with the pressure receiving part pilot line 6a and a branch point with the back pressure part pilot line 6b.

The operation of the embodiment constructed as described above will be described below.

(1) Actuators (TL, TR, SW, ARM, BM, OPT, B
When KT) and the like are all neutral, the oil discharged from the first hydraulic pump P1 and the second hydraulic pump P2 is immediately returned to the tank T through the center bypass passages 101 and 102 and the like.

(2) If the traveling motor side switching valves (V2, V5) are operated to operate the traveling motors TL, TR, the oil discharged from the first hydraulic pump P1 will flow through the parallel oil passage 103 and the switching valve V2. Through the left traveling motor TL
And the oil discharged from the second hydraulic pump P2 is supplied to the right traveling motor TR through the parallel oil passage 104 and the switching valve V5.
04 and the right and left traveling straight valve 2a
, 2b, etc. have the first state 1, so that the parallel oil passages 103
Is directly connected to the switching valve V2 through the internal oil passage of the left traveling straight valve 2a, and the parallel oil passage 104 is directly connected to the switching valve V5 through the internal oil passage of the right traveling straight valve 2b. Here, the left and right traveling straight valves 2a and 2b are respectively provided with a pressure receiving portion pilot line 6a at a pressure receiving portion and a back pressure portion.
Although the same pressure is acting through the back pressure section pilot line 6b and the back pressure section pilot line 6b, the pressure setting springs 5a and 5b can be provided in the first state I by the elastic force.

(3) While the traveling motors TL and TR are operating, the working equipment actuators SW, ARM,
At least one of BM, OPT, BKT, etc.
If one of them operates, the working device switching valves V1, V3, V4,
Among the V6, V7, etc., the selector valve S of the operated switching valve
1, while the SV3, SV4, SV6, and SV7 are moved, the cutoff pilot line 6c is communicated. Since the pilot line 6c communicates with the back pressure part pilot line 6b, the pilot line 6c
Pressure line pilot line 6 passing through orifice 7
b in the tank T through the pilot line 6c
Is returned to Eventually, the back pressure of the left and right oil passage switching valves 2a and 2b (the pressure in the pilot line 6b) is reduced by the orifice 7 as compared with the pressure of the pressure receiving portion (the pressure in the pilot line 6a). Due to the pressure difference between the pressure receiving portion and the back pressure portion, the left and right traveling straight valves 2a and 2b oppose the elastic forces of the pressure setting springs 5a and 5b and are switched to the second state II, respectively. When the left and right traveling straight valves 2a and 2b have the second state II, the above-mentioned merged oil passage 3 is connected. Accordingly, the oil discharged from the first hydraulic pump P1 and the second hydraulic pump P2 respectively flows through the parallel oil passages 103 and 104 to the left and right traveling straight valves 2a and 2b.
, The left and right sides are made uniform by the merging oil passage 3, and then the left and right traveling motors T are switched through the switching valves V 2 and V 5.
L and TR. The operating oil is also supplied to the operated working device system actuator through the parallel oil passage. For example, if the arm cylinder ARM is operated, the arm cylinder ARM side switching valve V3 from the first hydraulic pump P1 through the parallel oil passage 103 is operated. Oil is supplied to the side.

At this time, according to the prior art, the discharge oil amount of the first hydraulic pump P1 is distributed to the left traveling motor TL and the arm cylinder ARM, so that the total discharge of the left traveling motor TL and the second hydraulic pump P2 is performed. Although the supply of the oil amount is reduced compared to the right traveling motor TR which receives the supply of the oil amount, the equipment is deflected.
According to the present embodiment, the straight traveling valves 2a and 2b and the junction oil passage 3
As a result, the discharge oil amounts of the first hydraulic pump P1 and the second hydraulic pump P2 are merged, so that the overall oil amount (the first and second hydraulic pumps P1 and P2)
(Sum of the amount of oil discharged from hydraulic pump P1 and pump 2)
The remaining oil amount excluding the oil amount supplied to the arm cylinder ARM can be equally distributed to the left traveling motor TL and the right traveling motor TR.

The oil passing through the straight travel valves 2a, 2b is operated because a pressure loss occurs while passing through the orifices 4a, 4b formed in the internal oil passages of the straight travel valves 2a, 2b. Even if the required oil amount of the working device is larger than the required oil amount of the traveling motor, the operation of the working device can sufficiently occur.

According to the present embodiment, even if the working device is operated during traveling, the remaining oil excluding the oil amount required for operating the working device is included in the total amount of oil discharged from the two pumps. After the quantities are merged, they can be supplied after being evenly distributed to the left and right traveling motors, so that the equipment is not deflected to one side and the straight traveling can be maintained.

In addition, since the entire discharge oil amount of the two hydraulic pumps except for the oil amount required for operation of the working device can be supplied to the traveling motor, sudden movement of the equipment due to operation of the working device during traveling is possible. Maximum deceleration is prevented.

Such a function is particularly effective when operating a working device having a very small required oil amount, such as a bucket, while the equipment is running. (In the conventional case, the entire discharge oil amount of one hydraulic pump is supplied to the bucket, and the discharge oil amount of the remaining one hydraulic pump is distributed and supplied to the left and right traveling motors.) Since the amount of oil supplied to the traveling motor is partially limited due to the orifice provided therein, the operation can be performed even in the case of a work requiring a large amount of oil such as an arm-out (ARM-OUT). Sex is guaranteed.

[0026]

As described above, according to the traveling straight traveling device of the present invention, the traveling traveling device can be applied to various traveling heavy equipment such as an excavator and a crane, and the traveling traveling device can be operated even when the working device is operated. Of course, it is possible to maintain the straightness of the vehicle, and of course, the sudden deceleration of the traveling speed caused by the operation of the working device is not caused.
Running and work stability can be improved.

[0027]

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram illustrating a conventional excavator hydraulic circuit.

FIG. 2 is a hydraulic circuit diagram illustrating an excavator hydraulic circuit to which the straight traveling device according to one embodiment of the present invention is applied.

FIG. 3 is a detailed hydraulic circuit diagram of a straight traveling valve in FIG. 2;

[Explanation of symbols]

 1a Left parallel oil passage 1b Right parallel oil passage 2a Left traveling straight valve 2b Right traveling straight valve 3 Merging oil passage 4a, 4b Orifice 5a, 5b Pressure setting spring 51a, 51b Internal oil passage 6 Pilot line 6a Pilot line for receiving pressure section 6b Back Pressure section pilot line 6c Pilot line 7 Orifice P1 First hydraulic pump P2 Second hydraulic pump

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) E02F 9/22 B60K 17/10 F15B 11/17

Claims (4)

(57) [Claims] 1. A heavy equipment comprising first and second hydraulic pumps having the same capacity, left and right traveling motors operated by oil discharge amounts of the first and second hydraulic pumps, and a plurality of working device actuators. The straight traveling device according to claim 1 , wherein the first hydraulic pump and the left traveling motor have a left
Side parallel oil passage, the second hydraulic pump and the right traveling mode.
In the right parallel oil passage between the
Each hydraulic pressure is selected according to each spool movement.
Switching between left and right oil passages having a first state and a second state
Valve, and provided between the left and right oil passage switching valves
Including the confluence oil passage, when only the left and right traveling motors are activated
Means that the left and right oil passage switching valves are in the first state,
The left and right parallel oil passages and the merged oil passage are shut off from each other.
And the respective discharge oils of the first and second hydraulic pumps
Quantity is supplied to the left and right traveling motors respectively
So that the left and right traction motors are activated
And at least one of the working devices
When one of them is activated, the left and right oil passages
The switching valve is in the second state, and the left and right oil passages and the
The merging oil passages are connected to each other to form the first and second hydraulic ports.
After the discharge oil amount of the pump is merged, it is divided equally,
Heavy equipment straight running device supplied to left and right running motors . 2. The initial state of the left and right oil passage switching valves.
So that the left side and the right side are respectively in the first state.
The respective spools of the oil passage switching valve are elastically supported at a predetermined set pressure.
Pressure setting means to be held: branched from the first pilot line and left
And the right side oil passage switching valve
Pressure pilot pilot connected to apply
In and back pressure section pilot line: the plurality of branches branched from the back pressure section pilot line
At least one of the working devices
The pilot oil of the back pressure section pilot line
Raining second pilot line: and the first pilot line and the pressure receiving part and back pressure part pie
It is provided between each branch point etc. with the lot line etc.
By including the orifice, the second pie Rottora
Pilot of the back pressure section pilot line through the in
If oil is not drained, cut off the left and right oil passages
Each of the valve replacements maintains the first state, and the second pyro
The pilot line of the back pressure section through the pilot line
If the lot oil is drained, the pressure receiving part and back pressure
Depending on the pressure difference of the pilot line, the left and right
The side oil passage switching valves are each switched to the second state.
The straight traveling device of heavy equipment according to claim 1, wherein: 3. The second pilot line is connected to each of the work
After passing through all selector valves such as switching valves of the equipment, etc.
And provided to be connected to the drain line,
Selector valves etc. are spool neutral of the corresponding switching valve
When the second pilot line is shut off,
When moving the spool, connect the second pilot line
The straight traveling device for heavy equipment according to claim 2, wherein 4. The oil path disconnection of the left and right sides in the second state.
The parallel oil passage on the hydraulic pump side and the traveling motor in the valve
Side oil passages are connected to each other.
4. The method according to claim 1, further comprising a rifice.
Heavy equipment of the straight traveling device.