JP2741790B2 - Balance device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a ram balancing device that moves in a vertical axis direction in a machine tool.

<Prior Art> In a vertical feeder, the load on a driving unit is reduced by balancing the weight of a moving unit. As the balance device, a counterweight system in which a ram head and a weight are connected by a wire hung on a pulley and a cylinder type in which a cylinder and a ram head are connected by a wire hung on a pulley are generally adopted. I have.

<Problems to be Solved by the Invention> In the case of the above counterweight method, resistance due to frictional force at the pulley portion occurs, and the moving mass increases by the weight, so that the load at the time of acceleration / deceleration of the ram head increases. There is a defect.

Further, in the case of the cylinder type, when the cylinder is stopped and moved for a long time due to the leak of hydraulic oil, the balance force becomes unstable due to the resistance fluctuation of the seal portion, and is not suitable for high-precision positioning.

<Means for Solving the Problems> The present invention is to provide a balance device that has solved the above-mentioned conventional problems, and its characteristic configuration is guided by a shaft head body so as to be movable in a vertical axis direction, A rotation stopper bar connected via a connecting plate to a ram that moves up and down by a lifting drive device, a screw rotatably supported on the shaft head body in parallel with the ram, and rotationally driven by a screw rotation motor;
A nut screwed to the screw and supporting the rotation-stop bar via a spring, a sensor for detecting the position of the nut with respect to the ram or the position of the nut with respect to the rotation-stop bar, and inputting a detection signal of the sensor; And a control device for controlling the screw rotation motor so that the position of the nut with respect to the rotation preventing bar is constant.

<Operation> With the above configuration, the weight of the ram is supported by the spring via the rotation preventing bar, and the screw is rotated by the screw rotation motor according to the position command from the control device with the movement of the ram, and the nut is moved to the ram. By moving up and down by an amount equal to the moving amount, the set load of the spring is kept constant, and the ram weight is balanced.

<Example> Hereinafter, an example of the present invention will be described with reference to the drawings. First
In the figure, reference numeral 1 denotes a shaft head main body, which is fixed to a fixing part (not shown). Reference numeral 2 denotes a ram which is supported on the shaft head body 1 so as to be movable in a vertical axis direction. At the lower end of this ram 2,
For example, a processing unit such as a grindstone head 3 is attached.

An operating bar 4 is coaxially connected to the upper end of the ram 2, and the operating bar 4 is moved up and down by a traction drive device 5.

The traction drive device 5 includes a traction drive roller 6 that comes into contact with the operation bar 4 and a traction drive motor 7 that rotates the traction drive roller 6.

Reference numeral 8 denotes a detent bar that is movably supported on the shaft head body 1 along an axis parallel to the axis of the ram 2. The rotation preventing bar 8 and the ram 2 are connected by a connecting plate 9 so that both the ram 2 and the rotation preventing bar 8 are prevented from rotating.

Reference numeral 10 denotes a screw rotatably supported on the shaft head body 1 on the same axis as the rotation preventing bar 8, and the rotation is transmitted by a screw rotation motor 11 and a gear 12. A nut 13 is screwed to the screw 10 so as to be vertically movable by a lead of the screw 10. A spring 14 is interposed between the nut 13 and the rotation preventing lever 8, and a guide bar 30 provided on the rotation preventing bar 8 side is inserted into a through hole 31 of the nut 13 to prevent the rotation of the nut 13. Is made. The shaft head body 1
The weight of the ram 2, the grinding wheel head 3, and the like is supported by screws 10, nuts 13, springs 14, and detent bars 8.

Reference numeral 15 denotes a laser length measuring device, which is fixed to the shaft head main body 1. A mirror 16 is fixed to the lower end of the ram 2 so as to face the laser-side elongate unit 15, and the laser-side elongate unit 15 and the mirror 16 constitute a movement amount sensor for the ram 1.

Reference numeral 17 denotes a scale fixed to the rotation stopper bar 8, and a reading head 18 is fixed to a nut 13 facing the scale, and the scale 17 and the reading head 18 constitute a nut position sensor.

Reference numeral 19 denotes an NC control device for controlling the traction drive motor 7 and the screw rotation motor 11. The NC control device 19 and the traction drive motor 7 are compared with a comparison circuit 20 and a drive circuit 21.
, And the screw rotation motor 11 is connected to the comparison circuit 22 via the drive circuit 23.

The detection signal of the laser length measuring device 15 is input to the comparison circuit 20, and the detection signal of the read head 18 is input to the comparison circuit 22.

Since the present invention has the above-described structure, the weight of the ram 2 and the like is balancedly supported by the spring 14 via the rotation preventing bar 8.

The ram 2 is moved by the traction drive device 5 in response to a feed command from the NC control device 19. , The amount of movement of the ram 2 is detected, the detection signal and a feed command signal are compared and calculated by a comparison circuit 20, and a traction drive motor is driven by a drive circuit 21.

On the other hand, the rotation stop bar 8 is also moved by the movement of the ram 2, and the position of the nut 13 with respect to the rotation stop bar 8 is different, so that the set load of the spring 14 is changed. Therefore, the difference in the position of the nut 13 with respect to the rotation stopper bar 8 is detected by the scale 17 and the read head 18, and this is compared with a position command of the nut from the NC control device 19 by the comparison circuit 22 to calculate the position command. Nut 13 for actual detent bar 8
Then, the screw rotation motor 11 is driven so that the difference in the positions is eliminated. As another modified example, instead of a nut position sensor for detecting the position of the nut 13 with respect to the rotation preventing bar 8,
A nut position sensor for detecting the position of the nut 13 with respect to the shaft head body 1 is provided.
If the position signal of the ram from the control device 19 is given to the comparison circuit 22, the nut 13 can be moved by an amount corresponding to the movement of the ram 2.

<Effect of the Invention> As described above, the present invention relates to a rotation stopper bar which is guided by a shaft head main body so as to be movable in a vertical axis direction and is connected via a connecting plate to a ram which moves up and down by an elevating drive device, A screw rotatably supported on the shaft head body in parallel with the ram and driven to rotate by a screw rotating motor, a nut screwed to the screw and supporting the anti-rotation bar via a spring, A sensor that detects the position of the nut or the position of the nut with respect to the rotation-stop bar, and a control device that inputs a detection signal of the sensor and controls the screw rotation motor so that the position of the nut with respect to the rotation-stop bar becomes constant. Because it is configured, the moving weight is reduced, the servo responsiveness is improved,
Since the supporting force can be set continuously by the amount of deflection of the spring, the weight balance can be completely achieved.

Further, the screw portion for adjusting the position of the nut has a self-locking function to prevent the ram from falling.

[Brief description of the drawings]

FIG. 1 is a sectional view of the present invention together with a control circuit. 1 ... shaft head body, 2 ... ram, 4 ... operating bar, 5 ...
Traction drive device, 6 Traction drive roller, 7 Traction drive motor, 8 Rotating bar, 9 Connection plate, 10 Screw, 11 Screw rotation motor, 13 Nut, 14 … Spring, 15… Length on laser side, 16… Mirror, 17… Scale, 18… Read head, 19… NC controller.

Claims (1)

(57) [Claims] An anti-rotation bar which is guided by a shaft head main body so as to be movable in a vertical axis direction and which is moved up and down by a raising / lowering driving device and connected to a ram via a connecting plate; A screw rotatably supported by a screw rotation motor, a nut screwed to the screw and supporting the rotation preventing bar via a spring, a position of the nut relative to the ram or the rotation preventing bar A balance device comprising: a sensor for detecting a position of a nut with respect to the rotation control unit;