JP2682926B2 - Backhoe hydraulic controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is constructed so that a backhoe device is driven by a plurality of hydraulic actuators, and the opening degree of an electromagnetic proportional flow control valve of a hydraulic actuator for vertically moving a boom in the backhoe device is The present invention relates to a backhoe hydraulic control device provided with a flow rate control unit that supplies a current according to an operation amount of an operation lever to perform proportional control.

[0002]

2. Description of the Related Art In the hydraulic control device for a backhoe described above, conventionally, pressure oil from another hydraulic pump is used in addition to the main control valve of the boom driving hydraulic cylinder [an example of hydraulic actuator] for boom raising operation. A sub-control valve that joins the supply path is provided, and when the backhoe device is driven to rise, the backhoe device is configured to lift and drive with a large hydraulic pressure against the weight of the backhoe device (for example, an example of a hydraulic circuit configuration. See Japanese Patent Application Laid-Open No. 2-289726].

[0003]

In the above structure, in a normal excavation work, when the backhoe device is used to scoop the earth and sand, the boom is driven up by both the weight of the backhoe device itself and the weight of the earth and sand. Since a large weight load is applied, the pressure oils of the two hydraulic pumps are combined to increase the driving force during this ascending operation. By the way, in this type of backhoe, a bucket at the tip of the backhoe or, instead of the bucket, an iron pile is attached to lower the backhoe vigorously to perform concrete cracking and asphalt crushing work. However, in such a case, when pressure oil merging is performed during the ascending operation of the backhoe device as in the above-described conventional structure, the ascending operation speed of the backhoe device is faster than the descending operation for driving the pile. However, there is a drawback that a speed difference occurs in the vertical movement, which makes it difficult to perform the work. In such pile driving work, since the backhoe device is lowered and then quickly raised, in particular, in the configuration in which the current supply amount of the electromagnetic proportional flow control valve is controlled based on the lever operation, the raising operation is performed. At the same time, a response delay of the electromagnetic proportional flow control valve occurs, the backhoe device returns to a position higher than the desired position, and the lowering operation takes time, which deteriorates the workability. An object of the present invention is to eliminate the above disadvantages.

[0004]

According to a first aspect of the present invention, in the hydraulic control device for a backhoe described at the beginning, the operation lever is returned from a descending side operation area to a neutral position at a predetermined speed or more. And a neutral speed detecting means for detecting that a hydraulic actuator other than the boom hydraulic actuator is in a neutral state, and the lever speed detecting means and the neutral detecting means are provided. When both are in the detection state, there is provided a flow rate suppressing means for suppressing the amount of pressure oil supplied to the boom hydraulic actuator on the raising operation side to an amount smaller than the standard flow rate. The characteristic configuration of the second aspect of the present invention is a lever for detecting that each of the descending drive operation of the operation lever, the neutral maintaining operation, and the ascending drive return operation in the boom descending operation is performed at a high speed equal to or higher than a predetermined speed. An operating state detecting means and a neutral detecting means for detecting that a hydraulic actuator other than the boom hydraulic actuator is in a neutral state are provided, and both the lever operating state detecting means and the neutral detecting means are in a detecting state. Then,
A point is that a flow rate suppressing means is provided for suppressing the amount of pressure oil supplied to the boom hydraulic actuator on the raising operation side to be smaller than the standard flow rate. The characteristic configuration of the third aspect of the present invention is only when the lever operation state detection means has the lowering operation maintaining time after the boom lowering operation is the first predetermined time or more and the second predetermined time or less. The point is that the detection is activated.

[0005]

[Operation] In the case of pile driving work, after the pile body is quickly lowered and driven, it is necessary to perform the lever operation so as to raise the pile body quickly in a short time. The return operation to the neutral position is performed at a predetermined speed or higher, or the lowering operation of the operating lever, the neutral maintenance operation, and the return operation for raising drive of the operating lever are performed at high speeds higher than the predetermined speed. Only when both of the above operating conditions and the fact that the other hydraulic actuator is not operating are detected, it is judged that the lever operation is piling work, and the pressure on the lifting operation side is judged. Since the oil supply amount is automatically suppressed to a small amount, the ascending operating speed can be adjusted to an operating speed substantially equal to the descending speed. In addition, the lever operation state detecting means is configured to detect and operate only when the descending operation maintaining time after the boom descending operation is a first predetermined time or more and a second predetermined time or less. Then, for example, when the operator accidentally flips the operating lever by hand, the operation is not set to the pile driving work state, and the work can be performed safely.

[0006]

Therefore, it is possible to perform a well-balanced work for the vertical movement of the boom at almost the same operating speed by judging the lever operation state peculiar to the pile driving work. It is possible to suppress the rise and improve workability in pile driving work. Also, when the hydraulic actuator other than the boom cylinder is operating, or when the lifting lever is operated slowly or when the boom descending state continues for a long time, other than excavation work or pile driving. Therefore, the boom raising operation can be driven with a strong force when the two pumps are joined. Moreover, since such switching is automatically performed, the operator does not have to bother and the operability does not deteriorate.

[0007]

Embodiments will be described below with reference to the drawings. FIG.
Shows the backhoe. This backhoe is equipped with a hydraulic motor M for turning on a traveling machine base 2 equipped with a crawler traveling device 1.
The swivel base 3 is mounted on the swivel base 3 such that the swivel base 3 can be freely swiveled around the longitudinal axis by driving the
The travel base 2 is provided with a dozer device 5. The backhoe device 4 pivotally connects an arm 7 and a bucket 8 to a boom 6 that is pivotally supported on a swivel base 3 so as to be vertically swingable about a horizontal axis center. The cylinder 17 is driven and rocked so that excavation work or pile driving work such as concrete cutting can be performed. In addition, the boom 6 is divided into a base end portion 6a, an intermediate portion 6b and a tip portion 6c, which are pivotally connected to each other about a longitudinal axis, and the base end portion 6a and the tip portion 6c are connected to the intermediate portion 6b. The bucket 8 is pivotally connected via parallel links 9, and the offset cylinder 18 swingably drives the intermediate portion 6b so that the bucket 8 can move in the left-right direction while maintaining the parallel posture. It is configured to be laterally offset with respect to the portion 6a and stored on the swivel base 3 so that swivel operation can be performed in a state where the maximum swivel diameter is reduced.

The boom cylinder 15, the arm cylinder 16 and the bucket cylinder 1 as hydraulic actuators.
Each of the turning hydraulic motor M and the turning hydraulic motor M is configured to be controlled and operated by a pair of left and right operation levers 11 which are provided in a control unit 10 provided on the turning base 3 and which are capable of cross movement. More specifically, as shown in FIG.
5, 16 and 17 and the swing motor M are each configured to control the hydraulic flow rate by the electromagnetic proportional flow rate control valve V, and the operation amount of each operation lever 11 in each operation direction is detected by the four potentiometers PM. Then, the control device 12 controls the current supply amount to each electromagnetic proportional flow rate control valve V based on the detected manipulated variable. The offset cylinder 18 is configured to supply a preset flow rate by operating the operation switch SW. In the pressure oil supply circuit for the boom cylinder 15, as shown in FIG. 3, the main control valve V1 for supplying and discharging the reciprocating pressure oil from the first hydraulic pump 13 to the double-acting boom cylinder 15 and the boom 6 are used. And a sub-control valve V2 that joins and supplies the pressure oil from the second hydraulic pump 14 only to the pressure oil supply path on the ascending side of the boom cylinder 15. When hydraulic oils of the hydraulic pumps 13 and 14 are jointly supplied, for example, when a large weight is applied such as lifting the excavated earth and sand in a posture in which the backhoe device 4 is projected to the outside of the machine, a large hydraulic pressure acts. It is configured as follows. The control device 12 supplies a current according to the operation amount of the operation lever 11 to control the opening of the electromagnetic proportional flow rate control valve V, and the operation lever moves from the descending side operation area to the neutral position. With respect to the lever speed detecting means B for detecting a return operation at a predetermined speed or more, a neutral detecting means C for detecting that a hydraulic actuator other than the boom hydraulic cylinder 15 is in a neutral state, and the lever. Only when both the speed detecting means B and the neutrality detecting means C are in the detection state, the flow rate suppressing means D for controlling the amount of pressure oil supplied to the boom hydraulic cylinder 15 on the raising operation side to an amount smaller than the standard flow rate is controlled. It is provided in program form. That is, in the case of the pile driving work, the control device 12 executes the control as follows. As shown in FIG. 2, the outputs of the respective operation amount detecting potentiometers PM are read, and if the outputs of the potentiometers PM other than the boom operating potentiometer PM are not changed [steps 1 and 2], the boom potentiometer P is used.
When the output of M is operated beyond the predetermined position a to a position close to the maximum speed operation position on the descending side and is operated to the ascending side beyond the neutral operation area, the operation reaches from the predetermined position a to the neutral area. When the time t required for the operation is shorter than the set value tx [Steps 3 to 6], it is determined that the work is pile driving, and the boom auxiliary control valve V2 is maintained at the neutral position. , The current amount corresponding to the lever operation amount is supplied until the next rising side operation is performed only on the main control valve V1 [steps 7 to 9]. When the above-mentioned conditions are not satisfied, it is determined that the work is other work, and a current value corresponding to the operation amount of each potentiometer PM is supplied to each control valve V, and the boom 6 At the time of the raising operation, the main control valve V1 and the sub control valve V2 are similarly supplied with electric currents to perform the two-pump merging operation [step 10]. Then, the above-described control is repeatedly performed until reset (step 11). The flow rate control means A is constituted by the step 10, and steps 4 to 4 are performed.
6 constitutes the lever speed detecting means B, step 2 constitutes the neutrality detecting means C, and steps 7 to 9 constitute the flow rate suppressing means D.

[Other Embodiment 1] When the pile driving work is judged as described above, the main control valve V1 and the sub control valve V1 are replaced with the sub control valve V2 which is controlled to maintain the operation at the neutral position. The amount of current supplied to each of V2 may be suppressed to be small. [Second Embodiment] The control device 12 replaces the one having the lever speed detecting means B as described above, and as shown in FIG. 4, for lowering drive of the operation lever 11 in lowering operation of the boom 6. The control program may be provided with a lever operation state detecting means E for detecting that each of the operation, the neutrality maintaining operation and the ascending drive returning operation is performed at a high speed of a predetermined speed or higher. That is, the control device 12 executes the control as follows. As shown in FIG. 5, the outputs of the respective operation amount detecting potentiometers PM are read, and the potentiometers P other than the boom operating potentiometer PM are read.
If the output of M has not changed [steps 1 and 2], the operation of the output of the boom potentiometer PM is performed beyond the predetermined position a to a position close to the maximum speed operation position on the descending side, and the operation is performed beyond the neutral operation area. When operated to the ascending side, for example, as shown in FIG. 6, in the descending operation, the first lever operation time t1 from the neutral operation area to the predetermined position, and the descending side operation exceeding the predetermined position a are performed. Each of the lever operation time t2 and the third lever operation time t3 from the predetermined position a to the neutral operation range in the upward operation is measured, and the first lever operation time t1 is equal to or less than a predetermined value ta, Only when the second lever operation time t2 is the first predetermined time tb or more and the second predetermined time tc or less and the third lever operation time t3 is the predetermined time td or less, the pile driving is performed. It is determined that the [Step 3
~ 8], while maintaining the boom auxiliary control valve V2 at the neutral position, only the main control valve V1 is supplied with a current amount corresponding to the lever operation amount until the next rising side operation is performed [step 9- 11]. When the above-mentioned conditions are not satisfied, it is determined that the work is other work, and a current value corresponding to the operation amount of each potentiometer PM is supplied to each control valve V, and the boom 6 At the time of the raising operation, the main control valve V1 and the sub control valve V2 are similarly supplied with electric currents to perform the two-pump merging operation [step 12]. Then, the above-mentioned control is repeatedly performed until reset (step 13). The steps 4 to 8 constitute the lever operation state detecting means E.

[Third Embodiment] In the second embodiment, instead of controlling the operation of the sub-control valve V2 to maintain the neutral position, current supply to each of the main control valve V1 and the sub-control valve V2 is performed. The amount may be suppressed to a small amount.

[0011] In the claims, reference numerals are provided to facilitate comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is a control block diagram.

FIG. 2 is a control flowchart.

[Fig. 3] Hydraulic circuit diagram for driving the boom cylinder

FIG. 4 is a control block diagram of another embodiment.

FIG. 5 is a control flowchart of another embodiment.

FIG. 6 is a control characteristic diagram of another embodiment.

FIG. 7 is a side view of the backhoe.

[Explanation of symbols]

 4 Backhoe device 6 Boom 11 Operation lever 15 Hydraulic actuator A Flow rate control means B Lever speed detection means C Neutral detection means D Flow rate suppression means E Lever operation state detection means V1, V2 Electromagnetic proportional flow control valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yutarou Morishita 64 Ishizukita-machi, Sakai City, Osaka Prefecture Kubota Corporation Sakai Plant (56) Reference JP-A-5434 (JP, A) JP-A-5- 195551 (JP, A) JP-A-3-157503 (JP, A)

Claims (3)

(57) [Claims] 1. An electromagnetic proportional flow rate control of a hydraulic actuator (15) configured to drive a backhoe device (4) by a plurality of hydraulic actuators, and vertically driving a boom (6) of the backhoe device (4). Open the valves (V1) and (V2) with the operation lever (11).
A hydraulic controller for a backhoe equipped with a flow rate control means (A) for proportionally controlling by supplying a current according to an operation amount of the operating lever (11) from a descending side operating region to a neutral position. Lever speed detecting means (B) for detecting a return operation at a predetermined speed or more, and neutral detecting means (C) for detecting that a hydraulic actuator other than the boom hydraulic actuator (15) is in a neutral state. And the lever speed detecting means (B) and the neutral detecting means (C) are both in the detection state, the pressure oil supply amount on the raising operation side with respect to the boom hydraulic actuator (15) is higher than the standard flow rate. A hydraulic control device for a backhoe, comprising a flow rate suppressing means (D) for suppressing the amount to a small amount. 2. An electromagnetic proportional flow rate of the hydraulic actuator (15) configured to drive the backhoe device (4) by a plurality of hydraulic actuators and driving the boom (6) of the backhoe device (4) up and down. Open the control valves (V1) and (V2) with the operation lever (1
A hydraulic control device for a backhoe, comprising a flow rate control means (A) for proportionally controlling by supplying a current according to the operation amount of 1), wherein the operating lever (11) is used for lowering operation of the boom (6). Lever operation state detecting means (E) for detecting that each of the descending drive operation, the neutrality maintaining operation, and the ascending drive returning operation at a high speed equal to or higher than a predetermined speed,
Neutralizing detection means (C) for detecting that a hydraulic actuator other than the boom hydraulic actuator (15) is in a neutral state, and the lever operation state detecting means (E) and the neutrality detecting means (C). ) Are both detected, the backhoe hydraulic control device is provided with flow rate suppressing means (D) for suppressing the amount of pressure oil supplied to the boom hydraulic actuator (15) on the raising operation side to an amount smaller than the standard flow rate. . 3. The lever operation state detection means (E),
The backhoe according to claim 2, wherein the detection operation is performed only when the descending operation maintaining time after the operation for descending the boom (6) is a first predetermined time or more and a second predetermined time or less. Hydraulic control device.