JPH0248519Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a three-pump hydraulic system for a backhoe equipped with an earth removal plate.

[Prior art and problems]

In the conventional three-pump bucket hoe, the first
The arm switching valve, swing switching valve, and running switching valve (left) are connected in parallel to the pump, while the bucket switching valve, boom switching valve, and running switching valve (right) are connected in parallel to the second pump, and the third pump is connected in parallel to the bucket switching valve, boom switching valve, and running switching valve (right). The soil discharge plate switching valve is configured to be connected to the pump independently. Therefore, when performing a combined operation of [traveling + earth removal plate drive], the pressure oil of the first pump is supplied to the left traveling motor, and the second
The entire amount of pressure oil from the pump can be supplied to the right travel motor, and the pressure oil from the third pump can be supplied to the earth removal plate, allowing for straight travel even while the earth removal plate is being operated.

However, in this configuration, the first
The combined operation of two operations in the pump or the second pump, namely [swivel + arm drive] and (bucket drive + boom drive), cannot be performed as quickly and smoothly as in a two-pump bucket hoe; In addition, the 3rd pump was only used to drive the earth removal plate, and was not used at all and was wasted except for work on the earth removal plate, and as a result, the overall efficiency was reduced. was bad.

A hydraulic system that is an improved three-pump type is known as a solution to this problem. This hydraulic system basically handles the swing, bucket, boom, and travel (left) with the first pump, the arm, travel (right) with the second pump, and the soil removal plate with the third pump. At times other than earth removal work, the third pump is configured to join the boom.

According to this hydraulic system, two pumps in the first pump
When performing two operations, that is, [swing + boom drive], for example, even if the pressure oil of the first pump flows preferentially to the swing motor with lower pressure, the pressure oil of the third pump can be supplied to the boom. , the boom operating speed is not reduced. Therefore, the two operations within the first pump, ie, the [swinging + boom driving] operations can be performed smoothly. Therefore, if the second pump performs the arm operation, the three operations [swivel + boom drive + arm drive] can also be performed smoothly. Similarly, two and three operations of [boom drive + bucket drive] and [boom drive + bucket drive + arm drive] can be performed smoothly.

However, the combined operation of [swivel + bucket drive] within the first pump slows down the operation speed and cannot be performed smoothly due to the reasons mentioned above. For this reason, the three and four operations of [swivel + bucket drive + boom drive], [swivel + bucket drive + arm drive], and [swivel + bucket drive + boom drive + arm drive] cannot be performed smoothly. Ta.

In general, in Batsukuho equipped with earth removal plates,
Along with the combined operation of [traveling + earth removal plate drive], turning,
It is desirable to be able to smoothly perform 2-movement, 3-movement, and 4-movement of all combinations of arm, boom, and bucket.

Therefore, the swing switching valve and the left running switching valve are connected in parallel to the first pump, the bucket switching valve is connected in series to the swing motor, and the arm switching valve, boom switching valve, and the right running switching valve are connected to the second pump in series. The traveling switching valves are connected in parallel, and the soil removal plate switching valve is connected to the third pump, and when working other than the earth removal plate, the pressure oil of the third pump is connected to the boom switching valve via the soil removal plate switching valve. An improved circuit configured to merge with the boom was also proposed, but the speed was increased when the boom was raised, which increased the working speed and was convenient.
When the boom was lowered, the speed was too fast, which seriously worsened the balance of the Batskuhoe aircraft.

[Means for solving problems]

The present invention was developed in order to eliminate these drawbacks, minimize the shaking of the aircraft, and improve overall workability.The second pump is equipped with a swing switching valve, a bucket switching valve, and one pump. The traveling switching valves are connected in parallel, the other traveling switching valve and the arm switching valve are connected in parallel to the first pump, and the boom switching valve is connected in series with the arm switching valve and the soil removal plate switching valve, respectively. At the same time, the boom switching valve communicates with the third pump through the communication path of the inlet/outlet port in the neutral position of the earth removal plate switching valve at the extreme position where the boom is switched to the boom lowering operation, and the boom switching valve is switched to the boom raising operation. The present invention is characterized in that the soil discharge plate switching valve and the arm switching valve are provided in communication with the first pump and the third pump at the extreme position through communication passages of the inlet/outlet ports at the neutral position of the arm switching valve, respectively.

[Effect]

With the above configuration, the third pump, which was previously used only for the earth removal plate, can be used as the first pump and the third pump when the boom is raised.
The pump's pressure oil is switched to the boom-raising operation of the boom cylinder at the extreme position by switching the pressure oil of the pump to the boom-raising operation via the communication path of the inlet/outlet port at the neutral position of the soil discharge plate switching valve and the arm switching valve. The boom switching valve at the extreme position merges into the bottom side chamber, and when the boom is lowered, only the pressure oil of the third pump is switched to the boom lowering operation via the communication passage of the entrance and exit port at the neutral position of the earth removal plate switching valve. It is supplied to the rod side chamber which is the boom lowering operation chamber of the boom cylinder, and when the boom is raised, it is connected so that the boom is driven by the merging of the 1st pump (main pump) + 3rd pump, and is used for dump loading work [combined operation of swing + boom ]
On the other hand, during excavation work, the boom is lowered to the excavation point at a moderate speed, and when it is time to return, it is returned smoothly by increasing the speed.

Furthermore, when performing a combined operation of [arm + boom], the arm can be operated by the first pump and the boom can be operated by the third pump, so the boom, arm,
The rotation and bucket operations are distributed to the first, second, and third pumps, respectively, and three types of combined operations are possible.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings.

As shown in FIGS. 1 and 2, the backhoe has a swivel base 2 installed on a crawler-type traveling vehicle body 1 so as to be able to drive the full range of rotation.
A driver's seat 4 is provided, and a bucket hoe device 8 consisting of a bucket 5, an arm 6, and a boom 7 is attached in front of the driver's seat. On the other hand, an earth removal plate 9 is attached to the crawler type traveling vehicle body 1.

The bucket 5, the arm 6, the boom 7, and the earth removal plate 9 rotate around their fulcrums by the expansion and contraction of the bucket cylinder 10, arm cylinder 11, boom cylinder 12, and earth removal plate cylinder 13, respectively.
The rotating platform 2 is rotated by a rotating motor 14, while the crawler type traveling vehicle body 1 is rotated by left and right traveling motors 15,
15'.

Bucket cylinder 10, arm cylinder 11,
Boom cylinder 12, earth removal plate cylinder 13, swing motor 14, and left and right travel motors 15, 1
5' is driven by three hydraulic pumps 16, 17, and 18, each of which is driven by an engine, and the driving and stopping of each cylinder and motor are provided between the cylinders and motors and the hydraulic pumps, as shown in FIG. By switching the bucket switching valve 19, the arm switching valve 20, the boom switching valve 21, the earth removal plate switching valve 22, the swing switching valve 23, the left running switching valve 24, and the right running switching valve 25, each switching valve The circuits of each pump system and the actuator such as the cylinder are controlled by cutting off communication with each other through each port.

The three-pump hydraulic system according to the present invention shown in FIG. 3 includes a bucket switching valve 19 for the second pump 17;
The swing switching valve 23 and the left travel switching valve 24 are connected in parallel, while the arm switching valve 2 is connected to the first pump 16.
0, the right travel switching valve 25 is connected in parallel, and the boom switching valve is operated regardless of the position of the soil removal plate switching valve 22 through the communication path of the entrance/exit port in the neutral position of the arm switching valve 20. Then, at another extreme position in the lower part of FIG. 3, the first pump is connected to the bottom side chamber a, which is a chamber to which pressurized oil is supplied to perform the lifting operation of the boom of the boom cylinder 12, that is, the lifting operation chamber. , and the third pump 18 is connected to the soil removal plate switching valve 22.
Furthermore, a boom switching valve 21 is added to this earth removal plate switching valve 22.
are connected in series, and when working on a work other than the earth removal plate 9, the boom switching valve 21 is
At another extreme position in the lower part of FIG. The bottom concubine a
and when the arm switching valve 20 is in the neutral position, the boom switching valve 21 is in another extreme position and the bottom side chamber a of the boom cylinder 12 is
The pressure oil of the first pump 16 supplied to At times, only the pressure oil of the third pump 18 is supplied through one extreme position above the boom switching valve 21 to the rod side chamber b, which is the lowering operation chamber of the boom of the boom cylinder 12. To add,
Normally, the capacity of the third pump is set to be smaller than that of the first and second pumps in relation to the horsepower of the engine room.

Further, the bucketed cylinder 10 is connected to the bucketed switching valve 19, and the arm cylinder 11 is connected to the arm switching valve 20.
However, if the boom cylinder 12 is connected to the boom switching valve 21,
Further, the soil discharge plate cylinders 13 are respectively connected to the soil discharge plate switching valves 22, and each cylinder is controlled by switching these switching valves. Further, the swing switching valve 23 is provided with a swing motor 14, and the left and right travel switching valves 24, 25 are provided with left and right travel motors 15, respectively.
15' is connected, and each motor is driven or stopped by operating the switching valve.

Therefore, when raising the boom, the first and third pumps 16,
The operation is extremely fast because the 18 pressure oils join together, and when lowering the boom, the boom is driven only by the pressure oil from the 3rd pump 18, so the boom can move up and down at an appropriate speed and with less shaking of the aircraft. Close.

〔effect〕

As described above, in the three-pump hydraulic system of the present invention, the second pump is connected in parallel with the swing switching valve, bucket switching valve, and one running switching valve, and the first pump 16 is connected with the other running switching valve and the arm switching valve. are connected in parallel, and the boom switching valve 21 is connected in series to the arm switching valve 20 and the earth removal plate switching valve 22, respectively, and the boom switching valve 21
The arm communicates with the third pump 18 through the communication path of the inlet/outlet port in the neutral position of the soil discharge plate switching valve 22 at the extreme position when the boom is switched to the lowering operation, and the arm is in the extreme position when the boom is switched to the upper position. The first pump 16 and the third pump 18 are connected to the first pump 16 and the third pump 18 through communication passages of the inlet/outlet ports in the neutral positions of the switching valve 20 and the soil removal plate switching valve 22.
When the boom is raised, the boom 7 is driven by the combined pressure oil from the first and third pumps 16 and 18, and when the boom is lowered, the boom 7 is driven by only the pressure oil from the third pump 18. The dynamic balance of the aircraft is good.

Furthermore, the three-pump hydraulic system according to the present invention, when performing a combined operation of [arm + boom],
Since the arm can be operated by the first pump 16 and the boom can be operated by the third pump 18, three operations (boom + arm + bucket) and three operations (boom + arm + swing) are possible. This has the advantage that the leveling work and the dumping work can be performed satisfactorily, the work efficiency is improved, and the work time can be shortened.

[Brief explanation of the drawing]

Figure 1 is a front view of a backhoe with a soil removal plate equipped with a built-in hydraulic system according to the present invention, and Figure 2 is a front view of the backhoe with a built-in hydraulic system.
The plan view of the vacuum hoe shown in the figure and FIG. 3 are circuit diagrams of a three-pump hydraulic system according to the present invention. 1...Crawler type traveling vehicle body, 2...Swivel base, 5
...Bucket, 6...Arm, 7...Boom, 9
...Earth removal plate, 10...Bucket cylinder, 11...
...Arm cylinder, 12...Boom cylinder, 1
3...Earth removal plate cylinder, 14...Swivel motor, 1
5, 15'...Travel motor, 16, 17, 18...
...Pump, 19...Bucket switching valve, 20...Arm switching valve, 21...Boom switching valve, 22...Soil removal plate switching valve, 23...Swivel switching valve, rod side chamber,
24, 25... Travel switching valve, a... Boom raising operation chamber (bottom side chamber) b... Boom lowering operation chamber (rod side chamber).

Claims (1)

[Claim for Utility Model Registration] A swing switching valve, a bucket switching valve, and one running switching valve are connected to the second pump, and an arm switching valve, a boom switching valve, and the other running switching valve are connected to the first pump. In addition, in the three-pump hydraulic system of the Buckhoe equipped with a soil discharge plate formed by connecting a soil discharge plate switching valve to the third pump, a swing switching valve, a bucket switching valve, and one travel switching valve are connected to the second pump. connected in parallel, the first
The other traveling switching valve and the arm switching valve are connected to the pump in parallel, and the boom switching valve is connected in series to the arm switching valve and the soil removal plate switching valve, respectively, and the boom switching valve is configured to lower the boom. At the extreme position when switched to operation, the soil removal plate switching valve communicates with the third pump via the communication path of the inlet/outlet port at the neutral position, and at the extreme position when switched to boom raising operation, the soil removal plate switching valve and arm switching are activated. A three-pump hydraulic system for a backhoe equipped with a soil discharge plate, characterized in that the soil discharge plate is provided to communicate with a first pump and a third pump through a communication path of an inlet/outlet port in a neutral position of the valve.