JPH09242127A - Hydraulic working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic shovel which enables reduction in fuel cost, lowering engine noise and prolong the service life of an engine. SOLUTION: An arm balance cylinder 9 is placed between a boom 3 raised by a boom cylinder 4 and an arm 5 swung by an arm cylinder 6, a port 9a on the side where the arm 6 of the arm balance cylinder 9 is raised and an accumulator 20 loaded on a swivel platform 2, are made to communicate with each other by a hydraulic pipeline 21. And then, the arm balance cylinder is made to assume responsibility for the dead load of the arm 5 and an excavation bucket 8, an action force at the time of excavation and a part of the weight of sand scooped by the excavation bucket.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of a hydraulic work vehicle, and more particularly to a boom of a hydraulic work vehicle supporting an arm, the weight of the boom, the arm and the work attachment, and the work attachment when working. The present invention belongs to the technical field of hydraulic work vehicles capable of reducing power energy required for work by giving a force that supports a part of the acting force.

[0002]

2. Description of the Related Art For example, a main body of a hydraulic excavator, which is a hydraulic work vehicle, is a crawler-type traveling carriage that supports a swivel so that the swivel is rotatable about a vertical axis. The boom includes a boom that is erected by a mounted boom cylinder, and an arm that is swingably supported by the tip of the boom and that is swingable by an arm cylinder that has one end pivotally attached to the boom. Then, a work attachment operated by an attachment operating cylinder whose one end is pivotally attached to the arm is attached to the tip of the arm.

The work attachment includes, for example, an excavation bucket, a grapple, a fork, a lifting magnet, and a traveling carriage having a tire traveling type. In the main body of the hydraulic excavator having such a configuration, the swivel base is swung, the boom is raised and lowered, the arm is swung, and the work attachment is operated to perform work corresponding to these work attachments. Of course, such a swivel operation of the swivel, a hoisting operation of the boom,
The swinging operation of the arm and the operation of the work attachment are performed individually or in combination.

[0004]

As described above, when operating such a work vehicle to perform work, the swivel base is swung, the boom is raised and lowered, the arm is swung, and the work attachment is operated. However, in addition to the weight of the boom, arm, and work attachment on the boom cylinder, a load during work acts on the work attachment.
At this time, the required power for raising the boom is extremely large, for example, about half of the total power. In that case, there is a problem to be solved that the engine mounted on the swivel must be fully rotated, which results in a large amount of fuel consumption.

Therefore, it is an object of the present invention to reduce the power required to raise the boom by supporting the weight of the boom, arm, work attachment and part of the working force acting on the work attachment during work. It is to provide a hydraulic work vehicle that makes it possible.

[0006]

The present invention has been made in view of the above circumstances, and therefore, in order to solve the above problems, the main means adopted by the hydraulic work vehicle according to claim 1 of the present invention. Is supported on the traveling carriage 1 by a boom cylinder 4 which is erected by a boom cylinder 4 whose one end side is pivotally attached to the traveling carriage 1, and an arm whose one end side is pivotally attached to the boom 3 at the tip of the boom 3. Rocked by the cylinder 6,
In a hydraulic work vehicle in which an arm 5 to which a work attachment 8 is attached is supported at its tip, an arm balance cylinder 9 is interposed between the boom 3 and the arm 5, and the arm 5 of the arm balance cylinder 9 is A balance hydraulic pressure supply device 20 for supplying accumulated hydraulic pressure is connected to the raising port 9a via a hydraulic pipe 21.

The main means adopted by the hydraulic work vehicle according to claim 2 of the present invention is the hydraulic work vehicle according to claim 1, wherein a boom balance cylinder 10 is provided between the traveling carriage 1 and the boom 3. A balance hydraulic pressure supply device 20 for supplying accumulated hydraulic pressure is connected to a port 10a of the boom balance cylinder 10 on the side where the boom 3 is raised via a hydraulic pipe 22.

A main means adopted by the hydraulic work vehicle according to claim 3 of the present invention is the hydraulic work vehicle according to claim 1 or 2, wherein the balance hydraulic pressure supply device is an accumulator 20. And

The main means adopted by the hydraulic work vehicle according to claim 4 of the present invention is the hydraulic work vehicle according to claim 1 or 2, wherein the balance hydraulic pressure supply device is the anti-boom 3 of the traveling carriage 1. It is a counterweight support cylinder 23 that supports a counterweight 24 mounted on the mounting side so as to be able to move up and down.

A main means adopted by the hydraulic work vehicle according to claim 5 of the present invention is the hydraulic work vehicle according to claim 3, wherein a hydraulic oil cooler is provided in the hydraulic pipe 21. To do.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A hydraulic work vehicle according to a first embodiment of the present invention will be described below with reference to FIG. 1 which is a side view of a hydraulic excavator as an example.
Is a crawler type traveling carriage equipped with a swivel base 2 which is swiveled around a vertical axis. One side of the driver's cab 2a of the swivel base 2 of the traveling carriage 1 has one end side on the swivel base 2. The tip ends of the piston rods of the pair of boom cylinders 4 pivotally attached are pivotally attached to the side surfaces, and the boom 3 which is undulated by the expansion and contraction of the piston rods is connected via a horizontal boom foot pin (not shown). An arm pin 3a is fitted in a horizontal pin hole provided at the tip of the boom 3,
The arm 5 is swingably connected by the arm pin 3a.

At one end of the arm 5, the tip of the piston rod of an arm cylinder 6, which is pivotally mounted at the head side via a pin to a bracket provided on the upper surface of the boom 3, is pivotally mounted. The arm 5 is configured to swing with the arm pin 3a as a swing fulcrum by the expansion and contraction of the piston rod. Further, at the tip of the arm 5, an excavation bucket 8 which is a work attachment operated by expansion and contraction of a piston rod of an attachment operating cylinder 7 whose one end is pivotally attached to a bracket provided on the arm 5 is mounted. That is, the configuration described above is a well-known typical hydraulic excavator.

In the first embodiment, a part of the weight of the arm 5 and the excavation bucket 8 and a part of the acting force acting on the excavation bucket 8 are provided under the boom 3 of such a typical hydraulic excavator. A force application means having a configuration described later for applying a raising force to support is added. That is,
The force applying means has the head side pivotally attached to the opposite side of the arm cylinder 6 that swings the arm 5, that is, the lower side.
An arm balance cylinder 9 pivotally attached via a pin to a bracket provided on the opposite side of the attachment operating cylinder 7 whose piston rod side swings the excavation bucket 8.
And an accumulator 20 which is a balance hydraulic pressure supply device mounted on one side surface of the swivel base 2, and a hydraulic pipe 21 which communicates with the port 9a on the side where the arm 3 of the arm balance cylinder 9 is raised from the accumulator 20. ing. The hydraulic pipe 21 is attached along the swivel base 2 and the boom 3, and is composed of a steel pipe and a high-pressure rubber hose. Of course, the high pressure rubber hose may be used alone.

The pressure of the accumulator 20 is adjusted so that the force for raising the arm 5 becomes equal to the sum of the weight of the arm 5 and the weight of the excavation bucket 8. By adjusting the pressure of the accumulator 20 as described above, the arm cylinder 6 shares the difference in the raising force of the arm balance cylinder 9 and the weight of the excavated earth and sand from the sum of the weight of the arm 5 and the weight of the excavation bucket 8. Since the contraction force of the piston rod may be weaker than in the conventional case, it is possible to reduce the fuel consumption of the engine, reduce the engine noise, and extend the engine life.

The operation mode of the hydraulic excavator having the above structure will be described below. The swivel base 2 is swung, the boom 3 is raised and lowered, the arm 5 is swung, and the excavation bucket 8 is operated to excavate earth and sand. The excavated earth and sand and the like are loaded on, for example, a truck. In such a series of operations, in addition to the own weight of the arm 5 and the excavation bucket 8, the excavation force during excavation and the weight of the excavated earth and sand act on the arm cylinder 6. However, in the hydraulic excavator according to the present embodiment, the force imparting means having the above-described configuration is added, so that the arm 3 of the arm balance cylinder 9 is raised from the accumulator 20 of this force imparting means via the hydraulic pipe 21. Hydraulic pressure is transmitted to the port 9a.
Therefore, the arm balance cylinder 9 applies a raising force to the arm 5 in a direction to raise the arm 5.

By adjusting the set pressure of the accumulator 20, the weight of the arm 5 and the excavation bucket 8 and the weight of the excavated earth 8 which is the acting force acting on the excavation bucket 8 during excavation of the earth and sand. It is possible to carry out a part of the above by the arm balance cylinder 9, and perform a predetermined work such as excavation of earth and sand and loading on a truck while reducing the load on the arm cylinder 6.

In such excavation / loading work, the ratio of the operation of swinging the arm 5 in one cycle from the excavation of earth and sand to the end of the loading to the operation of the next excavation is Although it is about 1/4, it is not necessary to fully operate the engine during this 1/4, unlike the conventional case. The ratio of the operation of swinging the arm 5 in one cycle naturally varies depending on the type of work.

When performing such work, as described above, the set pressure of the accumulator 20 is set to an appropriate pressure according to the type of work. Therefore, depending on the degree of the set pressure, when the engine is stopped to suspend the work, the arm 5 may not be in a predetermined folding posture. In such a case, the boom cylinder 4 is operated to bend the arm 5 via the boom 3 and, for example, after the excavation bucket 8 is grounded, the hydraulic oil in the accumulator 20 may be returned to the hydraulic oil tank. .

By the way, in the work that requires frequent operation of the boom 3 and the arm 5, the expansion and contraction of the bladder in the accumulator 20 are frequently repeated, so that the gas in the bladder generates heat and the oil temperature of the pressure oil rises. To do. Therefore, practically, it is preferable to interpose a hydraulic oil cooler (not shown) for cooling the hydraulic oil in the hydraulic pipe 21. Also, although it is somewhat disadvantageous in reducing power, for example, the accumulator 2
The hydraulic oil in 0 may be circulated little by little, and the circulated oil may be cooled by a hydraulic oil cooler provided in the body of the hydraulic excavator.

Therefore, in comparison with the conventional hydraulic excavator,
A small amount of power is required to raise the arm 5, and it is not necessary to inject the engine so much, so that fuel consumption can be significantly reduced, while significantly reducing the noise of the engine and extending the life of the engine. Can be expected.

A hydraulic excavator according to a second embodiment of the present invention will be described with reference to the side view of FIG. However,
The difference between the second embodiment and the first embodiment lies in the mounting position of the arm balance cylinder. Therefore, the same parts are designated by the same reference numerals, and only the different points will be described. That is, as is well understood from the figure, an arm balance cylinder 9 is arranged in parallel with the arm cylinder 6 above the arm cylinder 6 for swinging the arm 5, and the arm 5 of the arm balance cylinder 9 is The piston rod side port 9a on the raising side and the accumulator 20 are made to communicate with each other through a hydraulic pipe 21.

Explaining the mode of operation of the hydraulic excavator having the above structure, the hydraulic oil accumulated in the accumulator 20 flows into the port 9a of the arm balance cylinder 9 through the hydraulic pipe 21 to give a raising force to the arm 5. Therefore, the second embodiment has the same effect as the first embodiment.

A hydraulic excavator according to a third embodiment of the present invention will be described below with reference to FIG. 3 which is a side view thereof.
However, the difference of the third embodiment from the first embodiment is that a boom balance cylinder is added in addition to the arm balance cylinder 9, and therefore the same parts are designated by the same reference numerals, and Explaining only the difference, the head side of the boom balance cylinder 10 is below the boom cylinder 4 that hoists the boom 3, and the swivel base 2 is located below the boom balance cylinder 10.
Pivotally attached to the arm cylinder 6
Is connected via a pin to a bracket provided on the lower side of the opposite side.

The boom balance cylinder 10
Port 10a on the side where the boom 3 is raised, that is, on the head side
A hydraulic pipe 22 communicates with the accumulator 20. The arm balance cylinder 9 may be provided on the upper side of the arm cylinder 6 as in the second embodiment. Further, in this example, there is one accumulator, but two accumulators, one for the arm balance cylinder and one for the boom balance cylinder 10, may be provided.

The operation mode of the hydraulic excavator according to the third embodiment will be described below. The port 9 of the arm balance cylinder 9 from the accumulator 20 through the hydraulic pipe 21.
The hydraulic pressure is transmitted to a, and the hydraulic pressure is also transmitted from the accumulator 20 to the port 10a of the boom balance cylinder 10 via the hydraulic pipe 22. Therefore, the boom balance cylinder 10 also receives part of the weight of the boom 3, the arm 5, the excavation bucket 8 or the weight of the excavated earth and sand, which is the acting force that acts on the excavation bucket 8 when excavating the earth and sand. To be held. Therefore, the boom 3,
Since a small amount of power is required to raise the arm 5, the effects of reducing fuel consumption, reducing noise, and improving the durability of the engine are greater than those of the first or second embodiment.

A hydraulic excavator according to a fourth embodiment of the present invention will be described with reference to FIG. 4 which is a side view showing a partial cross section thereof. However, the difference between the fourth embodiment and the third embodiment is that the balance hydraulic pressure supply device is a counterweight support cylinder 23 described later.

That is, the counterweight supporting cylinder 23 is a counterweight 24 that is vertically guided by vertical and parallel guides (not shown) provided on the side of the swivel base 2 of the traveling carriage 1 opposite to the boom 3 side. It is arranged so as to support the weight, and the other end side of the hydraulic pipe 21 whose one end is connected to the port 9a of the arm balance cylinder 9 is connected to the port 23a on the side for pushing up the counterweight 24. In addition, the other end of the hydraulic pipe 22 having one end connected to the port 10a of the boom balance cylinder 10 is connected.

The counterweight support cylinder 23 can be applied to the first and second embodiments. When applied to the first and second embodiments, it is preferable to use one having a capacity equal to or larger than the capacity of the arm balance cylinder 9. That is, by adopting the counterweight support cylinder 23 having such a capacity, it is possible to apply a constant force to the piston rod of the arm balance cylinder 9 regardless of the stroke of the arm balance cylinder 9 to perform the expansion and contraction operation. .

Explaining the mode of operation of this hydraulic excavator, a pressure corresponding to the weight of the counterweight 24 is generated in the counterweight support cylinder 23, and the pressure oil of this pressure is passed through the hydraulic pipe 21 and the port 9a. The hydraulic piping 2 is supplied to the arm balance cylinder 9.
2, the boom balance cylinder 10 through the port 10a
Is supplied to. Therefore, since the arm balance cylinder 9 exerts a raising force on the arm 5 and the boom balance cylinder 10 exerts a raising force on the boom 3, the fourth embodiment has the same effect as the third embodiment. However, unlike the first, second or third embodiment, the fourth embodiment does not require a gas as a heat source that repeats compression and expansion unlike the accumulator, so that the first and second embodiments are not required. There is no need to provide a hydraulic oil cooler as in 2 or 3.

In the above description, a hydraulic excavator having a swivel base has been described as an example. However, even if the boom is a swing type, the tip of the arm of the hydraulic excavator body may have, for example, a grapple, a fork, or a lifting element. The technical idea according to the present invention can be applied not only to the one to which another work attachment such as a magnet is attached but also to the one in which the traveling carriage is a tire traveling type.

[0031]

As described above, according to the hydraulic work vehicle according to claims 1 to 5 of the present invention, the arm balance cylinder or the arm balance is provided between the boom and the arm of the hydraulic work vehicle. In addition to the cylinder, a boom balance cylinder is installed between the traveling carriage and the boom, and a port between the arm raising side of the arm balance cylinder or the arm raising side of the arm balance cylinder and the boom raising side of the boom balance cylinder. A balanced hydraulic pressure supply device that supplies the accumulated hydraulic pressure via hydraulic piping is connected to the. Therefore, the load on the arm cylinder that swings the arm and the load on the arm cylinder and the boom cylinder are reduced, so that the power required to operate the arm cylinder and the arm cylinder and the boom cylinder can be reduced. Therefore, there is a great effect on the reduction of the fuel consumption of the engine, the noise reduction of the engine, and the extension of the life of the engine.

[Brief description of drawings]

FIG. 1 is a side view of a hydraulic excavator according to a first embodiment of the present invention.

FIG. 2 is a side view showing a partial cross section of a hydraulic excavator according to a second embodiment of the present invention.

FIG. 3 is a side view of a hydraulic excavator according to a third embodiment of the present invention.

FIG. 4 is a side view showing a partial cross section of a hydraulic excavator according to a fourth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Traveling vehicle 2 ... Revolving base, 2a ... Driver's cab 3 ... Boom, 3a ... Arm pin 4 ... Boom cylinder 5 ... Arm 6 ... Arm cylinder 7 ... Attachment actuation cylinder 8 ... Excavation bucket 9 ... Arm balance cylinder, 9a ... Port 10 … Boom balance cylinder, 10a… Port 20… Accumulators 21, 22… Hydraulic piping 23… Counterweight support cylinder, 23a… Port 24… Counterweight

Claims (5)

[Claims] 1. A traveling carriage 1 supports a boom 3 which is undulated by a boom cylinder 4 whose one end side is pivotally attached to the traveling carriage 1, and one end side of the boom 3 is pivotally attached to the tip of the boom 3. Is rocked by the arm cylinder 6
In a hydraulic work vehicle in which an arm 5 to which a work attachment 8 is attached is supported at its tip, an arm balance cylinder 9 is interposed between the boom 3 and the arm 5, and the arm 5 of the arm balance cylinder 9 is A hydraulic work vehicle characterized in that a balance hydraulic pressure supply device 20 for supplying hydraulic pressure accumulated through a hydraulic pipe 21 is made to communicate with the port 9a on the rising side. 2. A boom balance cylinder 10 is provided between the traveling carriage 1 and the boom 3, and a hydraulic pressure accumulated through a hydraulic pipe 22 is provided in a port 10a of the boom balance cylinder 10 on which the boom 3 is raised. The hydraulic work vehicle according to claim 1, further comprising: a balance hydraulic pressure supply device 20 that supplies the hydraulic pressure. 3. The hydraulic work vehicle according to claim 1, wherein the balance hydraulic pressure supply device is an accumulator 20. 4. The balance hydraulic pressure supply device is a counterweight support cylinder 23 that supports a counterweight 24 mounted on the side opposite to the boom 3 of the traveling carriage 1 so as to be able to move up and down. 2. The hydraulic work vehicle described in 2. 5. The hydraulic work vehicle according to claim 3, wherein a hydraulic oil cooler is provided in the hydraulic pipe 21.