JPH0527301U - Inertial body control device for hydraulic equipment - Google Patents

Abstract

(57) [Summary] [Purpose] In hydraulic equipment that operates inertial bodies such as cranes, prevents hunting when the inertial bodies are stopped and improves operability. A displacement sensor 41 for detecting an operation amount of an operating lever 37 and an acceleration sensor 42 for detecting an acceleration of an inertial body 38 are provided. Two main pipelines 34, 35 connecting the directional control valve 32 and the hydraulic motor 33 are connected via an electromagnetic switching valve 43. The outputs of the displacement sensor 41 and the acceleration sensor 42 are input to the control device 44. The control device 44 detects the acceleration change of the inertial body 38 immediately before the stop at the time of the stop operation, opens the electromagnetic switching valve 43, equalizes the internal pressures of the two main pipelines 34, 35, and closes it at the time of the stop.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an inertial body control device for hydraulic equipment, and more particularly to an inertial body control device that prevents hunting when stopping the operation of the inertial body.

[0002]

[Prior Art]

 A conventional inertial body control device used for large hydraulic equipment 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 pipelines 2 and 3 are connected via a directional control valve 4, and the two main pipelines 2 and 3 are connected to a hydraulic motor 5. The switching of the directional control valve 4 is performed by the operation lever 7 of the operation unit 6, and the hydraulic motor 5 for driving the inertial body 8 such as the crane can be normally rotated, reversely rotated, and stopped. In addition, two relief valves 9 and 10 and two reversal prevention valves 11 and 12 are provided to connect to the two main pipe lines 2 and 3, respectively, and bypass pipe lines 13, 14, 15, 16 are formed. There is.

In the figure, when the operating lever 7 is rotated in the direction of arrow A, the directional control valve 4 is switched from the neutral “closed” position C to the B position, and the main pipeline 2 and the hydraulic pump 1 are connected to each other. In communication with each other, the hydraulic motor 5 is rotated in one direction to drive the inertial body 8. When the operating lever 7 is returned to the neutral position, the directional 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 decelerates and rotates by inertia until it stops to rotate the hydraulic motor 5, so that the pumping action of the hydraulic motor 5 increases the pressure force of the other main pipeline 3, An imbalance occurs in the internal pressure of the main pipelines 2 and 3 of the book. Here, the operation in the case where the reversal prevention valves 11 and 12 are not provided will be described. The inertial body 8 reverses due to the pressure difference between the two main pipelines 2 and 3 after stopping once, and the inertial motion at this time As a result, the pressure difference between the main pipelines 2 and 3 is reversed and then reversed again. This sway takes a long time until the inertial body 8 is hunted and stands still until the pressure difference is eliminated, which deteriorates the operability.

The reversal prevention valves 11 and 12 are provided to prevent this hunting. For example, when the directional control valve 4 is switched from the B position to the "closed" position C, the pressure of the other main pipeline 3 increases due to the inertia of the inertial body 8 as described above. The pilot ports 17 and 18 on both ends of the reversing prevention valve 11 on the left side in the figure are connected to the other main pipeline 3 by pilot pipelines 19 and 20, but one pilot pipeline 20 is provided with a throttle 21. ing. Therefore, when the pressure in the main pipeline 3 rises, there is a time lag in the rise in the pressure applied to the two pilot ports 17, 18, and after switching the valve to the O position and communicating the two main pipelines 2, 3. , Immediately returns to the “closed” position C. As a result, the pressures in the main pipelines 2 and 3 are made equal to prevent subsequent hunting of the inertial body 8.

[0006]

[Problems to be solved by the device]

 The above-described reversing prevention valve of the conventional inertial body control device opens an extremely short time by catching the pressure increase in the main pipeline that occurs when the inertial body turns beyond the position where it should stop. Therefore, the bypass action may not be sufficient, and it does not operate below the set value, and minute hunting cannot be eliminated. In addition, it is not easy to set the throttle for operating the check valve, and it is difficult to obtain a satisfactory effect.

Therefore, the hunting at the time of stopping the inertial body is eliminated, and it is solved in order to improve the operation feeling and the workability by improving the followability of the motion of the inertial body to the stop instruction of the operation lever. A technical problem that should be made arises, and this invention aims to solve the above problem.

[0008]

[Means for Solving the Problems]

 This invention is proposed to achieve the above-mentioned object, and in a hydraulic device in which an inertial body is driven by a hydraulic actuator, two main pipelines respectively connected to two ports of the hydraulic actuator are provided. A sensor connected to the electromagnetic switching valve to detect the driving operation amount of the operating portion, a sensor to detect the acceleration of the inertial body, and a control device to control the electromagnetic switching valve according to the detection value of the sensor are provided. A reference acceleration gradient value is set in the storage unit of the control device, the operation amount and acceleration calculating means and the comparing means for comparing the detected acceleration gradient value with the reference value are provided, and the inertial body at the time of the stop operation is provided. An inertial body control device in a hydraulic device configured to set the electromagnetic switching valve to the "open" position only when the acceleration gradient of is larger than the reference value.

[0009]

[Action]

 The control device calculates the acceleration of the inertial body and the drive operation amount of the operation unit. The stop operation and the drive operation are discriminated based on the drive operation amount and its change amount. In addition, whether the inertial body is stationary or in motion can be determined based on the operation amount and acceleration. During the stop operation, the inertial body decelerates while moving due to inertia, and stops due to back pressure in the main pipeline. Immediately before this stop and during the stop, the acceleration rapidly increases from the negative direction to zero. When this acceleration gradient reaches the reference acceleration gradient value set in the control unit, a control signal is output from the control unit to the electromagnetic switching valve, and the two main pipelines connected to the two ports of the hydraulic actuator communicate. To equalize the internal pressure of the main pipeline. As a result, the inertial body stops without hunting, the acceleration becomes zero, the control output to the electromagnetic switching valve is turned off, the two main pipelines are disconnected, and the inertial body remains stationary.

Further, since the stop operation and the drive operation are discriminated and the control signal is not output at the time of the drive operation, the electromagnetic switching valve operates even if the acceleration gradient at the start of the inertial body exceeds the reference value. The operation of the hydraulic actuator does not stop.

[0011]

【Example】

 An embodiment of the present invention will be described below in detail with reference to the drawings. In FIG. 1, 31 is a hydraulic pump. The hydraulic pump 31 is connected to a three-position four-port directional control valve 32, and the directional control valve 32 and the hydraulic motor 33 are connected by two main pipes 34 and 35 to prevent the hydraulic motor 33 from rotating normally, reversely, and stopping. Control. The direction control valve 32 is controlled by the turning position of an operation lever 37 provided on the operation unit 36. The hydraulic motor 33 is connected to an inertial body 38 such as a revolving body of a construction machine to drive the inertial body 38. In addition, two relief valves 39 and 40 are arranged between the main pipes 34 and 35 to connect the main pipes 34 and 35, and one relief valve 39 is provided when the hydraulic pressure in the main pipe 34 becomes equal to or higher than a set value. The hydraulic fluid is bypassed from the main pipeline 34 to the other main pipeline 35, and the other relief valve 40 bypasses the hydraulic fluid from the other main pipeline 35 to the main pipeline 34 when the pressure difference is opposite.

The inertial body control device includes a displacement sensor 41 for detecting the displacement of the operating lever 37, an acceleration sensor 42 for detecting the acceleration of the inertial body 38, a 2-port 2-position normally closed electromagnetic switching valve 43, and a control device 44. The ports of the electromagnetic switching valve 43 are connected to the main lines 34 and 35, respectively. The control device 44 obtains the position of the operating lever 37, the acceleration of the inertial body 38, and the acceleration gradient from the outputs of the displacement sensor 41 and the acceleration sensor 42, and the storage unit 45 that holds the reference acceleration gradient set value described later. It comprises an arithmetic unit 46 for comparing the acceleration gradient with a set value, an output unit 47 for outputting a control signal to the electromagnetic switching valve 43, and a control unit 48 for controlling each of the above units. The control device 44 outputs a control signal from the output section 47 to the electromagnetic switching valve 43 when the detection values of the displacement sensor 41 and the acceleration sensor 42 satisfy a certain condition, and the two main pipelines 34, 35 are connected.

Next, the operation of the inertial body control device will be described with reference to FIGS. 2 and 3. FIG. 2 is a timing chart from the start to the stop of the inertial body 38. When the operating lever 37 is returned to the neutral position as shown at the time point H, the speed of the inertial body 38 is decelerated and stopped (time point J). Paying attention to the change in the acceleration G at this time, the acceleration in the negative direction rises to zero at the stop position. In this deceleration section (F → H), the pressure in the drive-side main conduit 34 decreases and the pressure in the return-side main conduit 35 increases, but at the time point J when the pressure difference between the two main conduits 34, 35 increases. If the above is eliminated, the hunting of the inertial body 38 will not occur. Therefore, just before the stop (I → J), the electromagnetic switching valve 43 may be turned on to connect the main pipes 34, 35 to each other. Here, the rising gradient of the acceleration from I to J in the negative direction to zero is detected. Then, the solenoid operated directional control valve 43 is operated.

First, an acceleration gradient value R that serves as a reference for operating the electromagnetic switching valve 43 is preset in the control device 44. This value should be smaller than the actual acceleration gradient shown in Fig. 2. Next, the control procedure will be described with reference to the flowchart of FIG. When the operation is started (step 101), the control device 44 reads the acceleration G and the displacement θ of the operating lever 37 (step 102), and calculates the displacement amount Δθ of the operating lever 37 (step 103). Next, Δθ is compared with zero (step 104). Here, when the operation lever 37 is in the neutral position, Δθ = 0 and the acceleration G = 0, so the process proceeds from step 104 through step 105 to step 109 to set the control output ic = 0. Therefore, the control signal ic is not output in the next step 108, and the process returns to step 102.

When the operation lever 37 is operated to drive the hydraulic motor 33, the change amount Δθ of the operation lever 37 is greater than 0. Therefore, the process proceeds from step 104 to step 109, and in the case of constant speed operation, the change amount Δθ = Since 0 and acceleration G = 0, the process proceeds from step 104 to step 109 via step 105, the control output ic = 0, and the electromagnetic switching valve 43 does not operate.

When the inertial body 38 is stopped, when the operation lever 37 is returned to the neutral position, it is judged in step 104 that Δθ <0, and the routine proceeds to step 105. Here, the acceleration G is compared with zero, and since G ≠ 0 because the vehicle is decelerating toward the stop, the process proceeds to step 106. However, as shown in FIG. 2, the acceleration gradient dG / Since dt is smaller than the reference acceleration gradient value R described above, the routine proceeds to step 109, where the control output ic is zero. Subsequently, in the deceleration period (H → I) after returning the operation lever 37 to the neutral position, Δθ = 0 and G ≠ 0, so that the process proceeds from step 104 to step 106 through step 105, Since the acceleration gradient dG / dt is smaller than the reference acceleration gradient value R as in the case described above, the routine proceeds to step 109, where the control output i c = 0.

Subsequently, when the acceleration gradient dG / dt rises above the reference acceleration gradient value R immediately before the inertia of the inertial body 38 and the pressure in the main pipeline 35 are balanced and the inertial body 38 stops. → J), the process proceeds from step 106 to step 107, and the control output ic = ic is output as shown in FIG. 2 (step 108). As a result, the electromagnetic switching valve 43 is in the "open" position O, and the pressure difference between the two main pipelines 34, 35 is eliminated. Then, when the acceleration G becomes zero at the time of stopping (J), the routine proceeds from step 105 to step 109, the control output ic is set to zero, the electromagnetic switching valve 43 is returned to the "closed" position C, and the main pipeline is closed. The communication between 34 and 35 is cut off, and the inertial body 38 is stopped.

In this way, the electromagnetic switching valve 43 is operated by the change in acceleration immediately before the stop, and the internal pressures of the two main pipe lines 34 and 35 are made equal when stopped, so that the inertial body 38 does not sway back and smoothly. It can be stopped. FIG. 4 shows another embodiment, in which pressure sensors 53 and 54 are provided in the operation pilot conduits 51 and 52 of the directional control valve 32 to detect the displacement of the operation lever 37, and the main conduits 34 and 35 are respectively provided with pressure sensors. 55 and 56 are provided to detect the acceleration G of the inertial body 38 from the change in pressure. It should be noted that the present invention can be modified in various ways without departing from the spirit of the invention, and it goes without saying that the invention covers those modifications.

[0019]

[Effect of the device]

 As described in detail in the above-mentioned one embodiment, this invention detects changes in the acceleration gradient of the inertial body immediately before the stop and communicates the two main pipelines to the hydraulic motor, and cuts off the communication at the time of stop. , The inertial body can stand still smoothly without causing hunting. Moreover, since hunting does not occur, it is possible to easily perform a very small amount of operation, which was difficult in the past, and to exert a remarkable effect in improving the operability of hydraulic equipment.

[Brief description of 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 equipment.

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

FIG. 4 is a configuration diagram 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 Motors 34, 35 Main Pipeline 36 Operating Section 37 Operating Lever 38 Inertial Body 41 Displacement Sensor 42 Acceleration Sensor 43 Electromagnetic Switching Valve 44 Control Unit 45 Storage Section 46 Computing Section 47 Output Section 48 Control Section R Reference Acceleration Gradient Value

Claims (1)

[Scope of utility model registration request] 1. In a hydraulic device in which an inertial body is driven by a hydraulic actuator, two main pipelines respectively connected to two ports of the hydraulic actuator are connected via an electromagnetic switching valve to drive an operating portion. A sensor that detects the amount,
A sensor that detects the acceleration of the inertial body, and a control device that controls the electromagnetic switching valve according to the detection value of the sensor are provided.
A reference acceleration gradient value is set in the storage unit of the control device, the operation amount and acceleration calculating means and the comparing means for comparing the detected acceleration gradient value with the reference value are provided, and the inertial body at the time of the stop operation is provided. The inertial body control device in a hydraulic device configured to set the electromagnetic switching valve to the "open" position only when the acceleration gradient of is larger than the reference value.