JPS6144741Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a workpiece clamping device in a hobbing machine.

In a hobbing machine in which the workpiece mounted on the table is pressed and clamped from above by the center, improvements in machining accuracy and high efficiency of the hobbing machine are achieved by increasing the pressing force of the center. However, in conventional hobbing machines, the pressing force of the center is usually about 500 to 700 kg, which is insufficient to achieve high precision and high efficiency.

On the other hand, it is not so difficult to increase the pressing force of the center, but if you increase the pressing force of the center to 1000 to 1500 kg in a conventional hobbing machine, the surface pressure load on the table receiving surface will increase to the allowable surface. It cannot be applied in practice because it exceeds the compressive strength.

In view of the above-mentioned conventional problems, the present invention aims to provide a workpiece clamping device that can increase the pressing force of the center in order to achieve higher precision and higher efficiency.

Embodiments of the present invention will be described below based on the drawings. FIG. 1 is an overall front view, and FIG. 2 is a hydraulic circuit diagram. In the figure, reference numeral 1 denotes a fixture, and a knife edge 8 for fixing a workpiece 2 is provided at the tip of the fixture, which is fixed on a table 14. Reference numeral 3 denotes a support arm that can slide up and down along the column 6, and has a center 7 at its tip that presses the workpiece 2 downward. 4 is a pressing cylinder that drives the support arm 3. 9 is a receiving surface for receiving a table 14 formed on the bed of the hobbing machine.
11 is a balance cylinder that moves upward by the hydraulic pressure supplied from the hydraulic pressure supply port, and the bearing 1
3 gives a lifting force to the table 14. In the hydraulic circuit diagram, 15 is a directional control valve, 16 is a pressure reducing valve, 17 is a sequence valve, 18 and 19 are pressure gauges, 20 is a P port, 21 is a drain, 22 is a tank, and 23 is a flow rate control valve. That is, the hydraulic circuit is configured such that an optimum balance pressure is generated on the table 14 according to the magnitude of the clamping force on the workpiece 2 due to the lowering of the support arm 3.

In the above device, when SOLA of the direction control valve 15 is excited, the support arm 3 is lowered by the drive cylinder 4 and presses the workpiece 2. Therefore, if the pressure set in advance in the pressure reducing valve 16 is higher than the opening pressure value of the sequence valve 17, the sequence valve 17 becomes an open circuit,
The balance cylinder 11 operates to press the table 14 upward and balance it with the pressing force of the support arm 3. In addition, the sequence valve 17
The pressure is adjusted by the flow rate control valve 23. Unclamping work 2 is done using SOLB of directional control valve 15.
When energized, the support arm 3 will rise.

According to the present invention, when the workpiece clamping force exceeds a certain level, a force is applied to the table to cause a balancing action, so that surface pressure exceeding an allowable value does not occur on the table receiving surface. Therefore, the workpiece clamping force can be increased, and the hobbing machine can realize highly accurate and highly efficient machining.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of the present invention, and FIG. 2 is a hydraulic circuit diagram. 1... Fixture, 2... Work, 3... Support arm, 7... Center, 11... Balance cylinder, 14... Table.

Claims (1)

[Scope of utility model registration request] In a hobbing machine equipped with a device for clamping a workpiece using a workpiece fixture provided on the table and a center member that concentrically presses the workpiece placed on the workpiece fixture, the table is oriented toward the center member. A balance cylinder is provided to make the table movable and to drive the table, and pressure oil is supplied to the balance cylinder via a sequence valve from an oil passage for supplying pressure oil to a clamp cylinder that drives the center member. A workpiece clamping device for a hobbing machine.