JP2531265Y2 - Inertial control system for hydraulic equipment - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inertial body control device for hydraulic equipment, and more particularly to an inertial body control device for preventing hunting when stopping the operation of an inertial body.

[0002]

2. Description of the Related Art A conventional inertial body control device used for a large hydraulic device such as a hydraulic excavator will be described with reference to FIG. As shown in the figure, the hydraulic pump 1 and the two main lines 2 and 3 are connected via a directional control valve 4, and the two main lines 2 and 3 are connected to a hydraulic motor 5. Switching of the direction control valve 4 is performed by an operation lever 7 of an operation unit 6, and the hydraulic motor 5 that drives an inertial body 8 such as a crane can be rotated forward, backward, and stopped. Further, two relief valves 9 and 10 and two anti-reversing valves 11 and 12 are provided and connected to two main lines 2 and 3, respectively, and bypass lines 13 and 1 are provided.
4, 15, and 16 are formed.

In FIG. 1, when the operating lever 7 is turned in the direction of arrow A, the direction control valve 4 is switched from the neutral "closed" position C to the position B, and the one main pipeline 2 and the hydraulic pump 1 are connected. The hydraulic motor 5 is rotated in one direction by the communication, and the inertial body 8 is driven. When the operating lever 7 is returned to the neutral position, the direction control valve 4 returns to the "closed" position C, and the drive of the hydraulic motor 5 is stopped.

At this time, the inertial body 8 rotates by inertia until it stops while decelerating, and rotates the hydraulic motor 5, so that the other main pipeline 3 is pumped by the hydraulic motor 5.
And the internal pressures of the two main lines 2 and 3 become unbalanced. Here, the operation in the case where the reversal prevention valves 11 and 12 are not provided will be described. The inertial body 8 is reversed by the pressure difference between the two main pipelines 2 and 3 after stopping once, and the inertial motion at this time is performed. As a result, the pressure difference between the main pipelines 2 and 3 reverses and reverses again. This swing takes time until the inertial body 8 is hunted and stopped until the pressure difference is eliminated,
The operability will be degraded.

The reversing prevention valves 11 and 12 are provided to prevent this hunting. For example, the directional control valve 4
Is switched from the B position to the "closed" position C, the inertia of the inertial body 8 causes the pressure in the other main line 3 to rise as described above. After the inertial body 8 is once stopped by the braking back pressure, the inertial body 8 is reversed by the pressure difference between the main pipelines 2 and 3, and the pressure of one of the main observation paths 2 is increased. The pilot ports 17 and 18 at both ends of the check valve 12 on the right side in FIG.
Each of the pilot lines 20 is provided with a throttle 21. Accordingly, when the pressure in the main line 2 rises, there is a time difference in the increase in the pressure applied to the two pilot ports 17 and 18, and the check valve 12 is switched to the O position to connect the two main lines 2 and 3. Later, it immediately returns to the "closed" position C. Thus, the hunting of the inertial body 8 is prevented by setting the pressures of the main pipelines 2 and 3 to the same pressure.

[0006]

The above-described anti-reversal valve of the conventional inertial body control device described above opens for a very short time by catching a rise in the pressure in the main line caused when the inertial body turns beyond the position to be stopped. Things. Therefore, the bypass effect may not be sufficient, and if the value is less than the set value, the operation is not performed and the minute hunting cannot be eliminated. In addition, it is not easy to set a throttle for operating the check valve, and it is difficult to obtain a satisfactory effect.

[0007] In view of the above, the problem is solved in order to eliminate hunting when stopping the inertial body and to improve the followability of the operation of the inertial body to the stop instruction of the operation lever to improve the operational feeling and the workability. Technical challenges arise,
The purpose of this invention is to solve the above problems.

[0008]

SUMMARY OF THE INVENTION The present invention is proposed to achieve the above-mentioned object. In a hydraulic device in which an inertial body is driven by a hydraulic actuator, two hydraulic oil ports of the hydraulic actuator are provided. A sensor for detecting the motion of the inertial body by connecting the two main conduits connected to each other via an electromagnetic switching valve, means for judging the motion state of the inertial body from the detection value of the sensor, and calculating the motion speed thereof Means for setting, a reference speed setting means, a comparison means for comparing the reference speed and the motion speed of the inertial body, and a means for outputting a control current to the electromagnetic cutoff valve in accordance with the comparison result. Another object of the present invention is to provide an inertial body control device in a hydraulic device configured to set the electromagnetic switching valve to the "open" position only when the motion speed of the inertial body satisfies two conditions equal to or lower than a reference speed.

[0009]

The judging means judges whether the motion state of the inertial body is in one of the stopped state, the accelerated state, the steady state speed, and the decelerated state based on the output signal of a sensor such as a speed sensor or a rotation speed sensor. Further, the motion speed of the inertial body is calculated from the output signal of the sensor by the calculating means. The comparing means compares the motion speed with the reference speed when the inertial body is decelerating, and outputs a control current from the output means to the electromagnetic switching valve when the motion speed becomes lower than the reference speed. As a result, the electromagnetic switching valve is opened and the two valves connected to the two ports of the hydraulic actuator are opened.
The main pipelines communicate with each other to equalize the internal pressures of the main pipelines, and the inertial body stops without hunting. When the stop of the inertial body is detected, the control current to the electromagnetic switching valve is turned off,
The two main pipelines are disconnected from each other, and the inertial body stops.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. In FIG. 1, reference numeral 31 denotes a hydraulic pump. The hydraulic pump 31 is connected to a directional control valve 32 having three positions and four ports. The directional control valve 32 and the hydraulic motor 33 are connected to two main pipelines 34,
35, and controls forward rotation, reverse rotation and stop of the hydraulic motor 33. The direction control valve 32 is controlled by a turning position of an operation lever 37 provided on the operation unit 36. The hydraulic motor 33 is connected to an inertia body 38 such as a swing body of the construction machine and drives the inertia body 38. Further, the main pipelines 34, 35
Two relief valves 39, 40 are arranged between the main pipeline 3
4 and 35, and one relief valve 39 is connected to the main line 3
4 when the oil pressure becomes equal to or higher than the set value, the hydraulic oil is bypassed from the main line 34 to the other main line 35, and the other relief valve 40 is connected from the other main line 35 to the main line 34 when the pressure difference is reversed. To bypass hydraulic oil.

The inertial body control device comprises a speed sensor 41 for detecting the rotational speed of the inertial body 38, a normally closed electromagnetic switching valve 42 at a two-port two position, and a control device 43. The ports of the electromagnetic switching valve 42 are They are connected to main pipelines 34 and 35, respectively. The control device 43 obtains a rotation speed of the inertial body 38 from an output of the speed sensor 41 and a storage unit 44 that stores a reference speed R described later, calculates an angular acceleration from the rotation speed, compares it with zero, and Is compared with a reference speed R, an output unit 46 that outputs a control signal to the electromagnetic switching valve 42, and a control unit 47 that controls the above-described units. When the detection value of the speed sensor 41 satisfies a certain condition, the control device 43 outputs the electromagnetic switching valve 42 from the output unit 46.
And a control signal is output to the two main lines 34 and 35.

Next, the operation of the inertial body control device will be described with reference to FIGS. FIG. 2 is a timing chart from the start to the stop of the inertial body 38. When the operation lever 37 is returned to the neutral position as shown at time F → H, the speed of the inertial body 38 is reduced and stopped (F → J). In the initial stage (F → H) of the deceleration section, the pressure in the drive-side main line 34 decreases, and the pressure in the return-side main line 35 increases. If the pressure difference is eliminated, no hunting of the inertial body 38 will occur. Therefore, immediately before the stop (I → J), the electromagnetic switching valve 42
Is turned on to communicate with the main pipelines 34 and 35. In this case, the speed at the time point I is detected and the electromagnetic switching valve 42 is operated.

The control procedure will be described with reference to the flowchart of FIG. First, in order to operate the electromagnetic switching valve 42, a sufficiently low reference speed R shown in FIG.
Is set in the storage unit 44. When the engine is started (step 101), the control device 43 reads the rotational speed V of the inertial body 38 (step 102). In the initial state, the position of the operation lever 37 is neutral, the inertia body 38 is stopped, and the rotational speed V = 0, so that the angular acceleration α = 0,
Proceeding from step 104 to step 107, the control output i
Let c = 0. Therefore, no control signal is output to the electromagnetic switching valve 42 (step 108), and the process returns to step 102.

Next, when the operating lever 37 is turned to rotate the inertial body 38 at the time point D in FIG. 2, the angular acceleration α ≧ 0, and the steps from step 104 to step 10
Then, the control output is set to ic = 0. Therefore, the inertial body 3
8 is in the state of stopping, accelerating, and rotating at constant speed (D →
In F), regardless of the speed, the electromagnetic switching valve 43 does not operate and the inertia body 38 does not stop.

Subsequently, when the operating lever 37 is returned to the neutral position in order to stop the inertial body 38, (F → H) the angular acceleration α <0, and the steps 104 to 105 are performed.
To Here, the rotation speed V is compared with the reference speed R, and the rotation speed V of the inertial body 38 during the deceleration decreases to V ≦ R
The process proceeds to step 107 until (H → I). Then, at the time point I when V = R, the process proceeds from step 105 to step 106 to output a control signal ic as ic = ic (step 108). Thereby, the electromagnetic switching valve 42
Becomes the "open" position O, and the pressure difference between the two main pipelines 34 and 35 is eliminated. Then, when the inertial body 38 stops, J
And the process proceeds from step 104 to step 107, where the control output ic is set to zero and the electromagnetic switching valve 4
2 is returned to the "closed" position C, the communication between the main pipelines 34 and 35 is cut off, and the inertia body 38 is stopped.

As described above, the speed immediately before the stop is detected during the deceleration operation, and the electromagnetic switching valve 42 is opened just before the stop to equalize the internal pressures of the two main pipelines 34 and 35.
Does not occur and can be stopped smoothly. Note that the means for detecting the rotation state of the inertial body 38 is not limited to the above-described speed sensor 41, but may be an angular acceleration sensor. Further, the rotation speed of the inertial body 38 may be indirectly detected using a rotation speed sensor or the like that detects the rotation speed of the hydraulic motor 33.

FIG. 4 shows a control flow chart when an angular acceleration sensor is used. In step 202, the angular acceleration is read, and in step 203, the angular acceleration is integrated to obtain the rotation speed V. The operation is performed in the same manner as shown in FIG. As described above, the present invention can be variously modified without departing from the spirit of the present invention, and it is natural that the present invention extends to those modified ones.

[0018]

As described in detail in the above embodiment, the present invention detects the speed immediately before the inertia body stops, and communicates the two main pipelines to the hydraulic motor. Since the cutoff is performed, the inertial body stops smoothly without hunting. Since hunting does not occur, a very small amount of operation, which has been difficult in the past, can be easily performed, and the operability of the hydraulic device is significantly improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an inertial body control device.

FIG. 2 is a timing chart of the operation of the hydraulic device.

FIG. 3 is a control flowchart of the inertial body control device.

FIG. 4 is a control flowchart showing another embodiment of the inertial body control device.

FIG. 5 is a configuration diagram of a conventional inertial body control device.

[Explanation of symbols]

 33 Hydraulic motor 34, 35 Main pipeline 36 Operating part 37 Operating lever 38 Inertial body 41 Speed sensor 42 Electromagnetic switching valve 43 Control unit 44 Storage unit 45 Operation unit 46 Output unit 47 Control unit α Angular acceleration R Reference speed V Rotation speed

Claims (1)

(57) [Scope of request for utility model registration] In a hydraulic device for driving an inertial body by a hydraulic actuator, two main pipelines respectively connected to two hydraulic oil ports of the hydraulic actuator are connected via an electromagnetic switching valve, and A sensor for detecting motion, a means for determining a motion state of the inertial body from a detection value of the sensor, a means for calculating the motion speed, a setting means for a reference speed, a reference speed, a motion speed for the inertia body, And a means for outputting a control current to the electromagnetic shut-off valve in accordance with the comparison result, wherein the electromagnetic switching is performed only when the inertial body satisfies two conditions of a reference speed or less in a deceleration state. An inertial body control device in a hydraulic device configured to set a valve to an “open” position.