JPH0128955Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a positioner drive device that improves positioning accuracy by alleviating torque fluctuations in a hydraulic motor for driving a positioner.

Conventionally, positioners have been used as welding jigs for large structures to position workpieces. The tilting table on which the workpiece of this positioner is mounted is rotated and positioned at the tilted position by a single electric motor or hydraulic motor.

However, because the center of gravity of the tilting table on which the work is mounted moves horizontally depending on the rotational position from the horizontal, the moment differs depending on the tilting angle, and the load torque of the motor that drives this table fluctuates drastically. It is difficult to control the speed when driving the tilt table, and it is quite difficult to perform accurate positioning.

In addition, in order to alleviate the fluctuations in load torque due to changes in moment, conventionally a counterweight was sometimes installed to balance the changes in the workpiece's center of gravity, but a counterweight with a large capacity for positioning a heavy workpiece This positioner requires a large counterweight and a large space, which is disadvantageous in terms of cost and structure.

In view of the above-mentioned conventional drawbacks, the present invention is a positioner rotation drive device that can easily perform speed control and positioning by alleviating load torque fluctuations of a hydraulic motor even if the moment changes due to the tilt position of the tilt table. The purpose is to provide

In order to achieve this purpose, the present invention is equipped with a tilting table on which a work is mounted and a hydraulic motor that rotates this tilting table, and the workpiece mounted on the tilting table is tilted from a horizontal state by the rotation of the tilting table. In the positioner rotary drive device that rotates the workpiece to a tilted state and positions the workpiece in this tilted state, the hydraulic motor includes a first hydraulic motor and a second hydraulic motor, and detects the tilt angle of the tilting table. a rotational speed detector for detecting the rotational speed of the first hydraulic motor; and a torque fluctuation of the first hydraulic motor is set in advance in accordance with a tilt angle signal output from the inclinometer. a pressure control valve that controls the pressure of the first hydraulic motor in response to load torque fluctuations; and an electrohydraulic servo valve that controls the flow rate of the second hydraulic motor in response to a speed signal from the rotational speed detector. It is characterized by having the following.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

FIG. 1 is a plan view schematically showing the positioner of the present invention, and FIG. 2 is a side view thereof. In the figure, 1
is a base, and 2a and 2b are fixed to the base 1 by hydraulic motors that rotate the tilting table 3 about an axis 4, and the tilting table 3 is fixed to the output shaft side of the hydraulic motors 2a and 2b. Reference numeral 5 denotes an inclinometer that detects the deflection angle θ about the axis 4 from the horizontal position of the center of gravity G of the tilt table 3, and is attached to the output shaft of the hydraulic motor 2a. A tachometer generator 6 detects the rotation speed of the hydraulic motor 2a, and is attached to the output shaft of the hydraulic motor 2a.

FIG. 3 is a diagram showing the positioner rotation drive hydraulic circuit of the present invention, in which the pressure oil of the hydraulic pump 7 is supplied to the hydraulic motor 2a via the check valve 8 and the electromagnetic switching valve 9. For pressure oil, use electromagnetic switching valve 9
is returned to the tank 10 via. Pressure control valve 11
is arranged between the hydraulic pump 7 and the tank 10, and controls the pressure of the pressure oil supplied from the hydraulic pump 7 to the hydraulic motor 2a. Pressure oil from the hydraulic pump 12 is fed to the hydraulic motor 2b via the electromagnetic switching valve 13 and the electrohydraulic servo valve 14, and the hydraulic motor 2b is returned to the tank 10 via the electrohydraulic servo valve 14. 15 is a relief valve that maintains the pressure of the pressure oil of the hydraulic pump 12 and releases it to the tank 10 when the pressure exceeds a predetermined value. Hydraulic pump 16 is electromagnetic switching valve 1
Pressure oil is supplied to the mechanical brakes 18a, 18b of the hydraulic motors 2a, 2a through the hydraulic motors 2a, 2a. 19 is a brake circuit relief valve.

Now, the operation of the positioner rotation drive circuit configured as described above will be explained with reference to the control block diagram in FIG. 4 and the tilt table rotation torque line and balance torque line in FIG. 5.

When a workpiece (not shown) is mounted on the tilt table 3 and the command switch 20 instructs the tilt table 3 to rotate from the horizontal position, the electromagnetic switching valve 17 changes from the A position to the B position.
mechanical brakes 18a, 18
Pressure oil from the hydraulic pump 16 acts on b to release the brake. At the same time, the electromagnetic switching valve 13 is also switched from the A position to the B position, and the pressure oil from the hydraulic pump 12 is sent to the hydraulic motor 2b via the electrohydraulic servo valve 14, thereby driving the hydraulic motor 2b. On the other hand, the pressure oil from the hydraulic pump 7 is sent to the hydraulic motor 2a via a check valve 8 and an electromagnetic switching valve 9 to drive the hydraulic motor 2a.

At this time, the rotational torque ratio for driving the tilting table 3 gradually decreases as shown by the solid line A in FIG. When it reaches , it becomes almost 0. Further, when the angle exceeds 90 degrees, the gravity of the tilting table 3 exerts a torque that tries to rotate the hydraulic motor. Therefore, the inclination angle θ of the incline table 3 is detected by the inclinometer 5 shown in FIG.
This value of θ is input to the control device 21 as an electric signal, and a signal p=f(θ) is generated, and a pressure p corresponding to p is applied to the pressure control valve 11 via the pressure generating means 22.
The hydraulic pump 7 controls the flow rate of the hydraulic oil that escapes from the hydraulic pump 7 to the tank 10 by adjusting its opening degree, and controls the pressure of the pressure oil sent from the hydraulic pump 7 to the hydraulic motor 2a. As a result, the hydraulic motor 2a is connected to the inclined table 3.
In order to balance most of the rotational torque for driving the motor, a driving torque as shown by the chain line in FIG. 5B is generated.

On the other hand, the tachometer generator 6 shown in FIG. The electro-hydraulic servo valve 14 determines its opening degree in response to the V signal, and pressure oil is supplied from the hydraulic pump 12 to the hydraulic motor 2b. Therefore, since most of the load on the hydraulic motor 2b is balanced by the hydraulic motor 2a, most of the variable load torque caused by the moment change accompanying the angle change of the tilt table 3, at least All you have to do is accept the difference between the two. In addition, the rotational speed of the hydraulic motor 2b is controlled via the electrohydraulic servo valve 14 so that there is little load variation and is always almost constant according to the rotational speed signal v of the tachogenerator 6, so accurate speed control is achieved. be able to.

When the deflection angle θ of the tilt table 3 exceeds 90°, the electromagnetic switching valve 9 is switched from the A position to the B position by a signal from the control device 21, and the hydraulic pressure in the circuit on the counter-rotation direction side of the hydraulic motor 2a is changed to an angle θ. Since the pressure control valve 11 works to increase the pressure according to the pressure, the hydraulic motors 2a,
The pressure of the hydraulic motor 2a is generated so as to balance the rotational torque of the tilting table 3 which attempts to drive the tilting table 2b by gravity. As a result, the load on the hydraulic motor 2b is small, and the influence of load fluctuations on speed control is alleviated.

According to the present invention described above, most of the load torque fluctuations of the hydraulic motor caused by changes in the angle of the tilting table of the positioner are balanced by one hydraulic motor, so that the other hydraulic motor has a light load and no load fluctuations. This makes it easier to control the speed, and as a result, it becomes possible to easily adjust the speed of the ramp using both hydraulic motors, allowing for highly accurate positioning of the ramp.

[Brief explanation of drawings]

FIG. 1 is a plan view schematically showing a positioner according to the present invention, FIG. 2 is a side view of FIG. 1, and FIG. 3 is a diagram showing a positioner rotation drive hydraulic circuit according to the present invention.
FIG. 4 is a control block diagram of the present invention, and FIG. 5 is a diagram showing a tilt table rotation torque line and a balance torque line. 2a, 2b...Hydraulic motor, 3...Slope, 4
...rotation axis, 5 ... inclinometer, 6 ... tachometer generator, 11 ... pressure control valve (pressure control means),
14...Electro-hydraulic servo valve (flow control means).

Claims (1)

[Scope of utility model registration request] It is equipped with a tilting table on which a work is mounted and a hydraulic motor that rotates the tilting table, and the workpiece mounted on the tilting table is rotated from a horizontal state to an inclined state by the rotation of the ramp, and in this inclined state, the workpiece is In a rotation drive device for a positioner that positions a workpiece, the hydraulic motor is a first hydraulic motor and a second hydraulic motor.
a hydraulic motor, an inclinometer for detecting the inclination angle of the inclination table, a rotation speed detector for detecting the rotation speed of the first hydraulic motor, and a inclination angle signal outputted from the inclinometer according to the inclinometer. a pressure control valve that controls the pressure of the first hydraulic motor so that the torque fluctuation of the first hydraulic motor corresponds to a preset load torque fluctuation; A rotation drive device for a positioner, comprising: an electro-hydraulic servo valve that controls the flow rate of the second hydraulic motor.