Machine tool

1. A machine tool comprising:

a support table provided on an upper surface of a bed to support a work;

a Z-axis saddle for reciprocation in a longitudinal Z-axis direction;

a machining unit mounted on the Z-axis saddle and provided with a machining head for machining of the work;

a compartment cover arranged on the bed to compartment a machining region, in which the work supported on the support table is machined, and a machine region, in which the machining unit is movably arranged;

an opening window provided on the compartment cover to permit the machining head to go in and out of the machining region therethrough; and

a seal member in the form of a closed ring to be mounted on an inner peripheral edge of the opening window of the compartment cover;

wherein an entire periphery of an outer peripheral surface of the machining head is brought into sliding contact with an inner peripheral edge of the seal member in a state, in which the machining head is moved into the machining region from a tool exchange position within the machine region.

2. A machine tool according to claim 1 , wherein the machining unit is configured to permit exchange of plural kinds of machining heads having different body sizes, the opening window is formed in the compartment cover to enable a machining head of a maximum size of the plural kinds of machining heads to go in and out of the opening window, and the opening window of the compartment cover selectively and exchangeably mounts thereto plural kinds of seal frames each comprising a mount frame formed with an opening window conformed to a body size of a corresponding one of each of the machining heads, and the seal member mounted to an inner peripheral edge of a respective one of the opening windows of the mount frames and put into contact with an outer peripheral surface of a body of the respective machining head.

3. A machine tool according to claim 2 , wherein guide rails are mounted immediately on the upper surface of the bed and the Z-axis saddle of the machining unit is mounted on the guide rails.

4. A machine tool according to claim 3 , wherein the seal member comprises a scraper having a seal lip and has a tip end thereof directed toward the machining region.

5. A machine tool according to claim 1 , wherein the machining unit is configured to permit exchange of plural kinds of machining heads having different body sizes, the seal member is conformed to a maximum body size of the machining heads and is mounted to the opening window, plural kinds of head covers formed into complementary shapes so as to assume the same shape as the external shape of a body of the machining head having the maximum body size upon mounting on those machining heads having sizes, which are equal to or less in size than the maximum body size, are selectively and exchangeably mounted on the machining unit when the machining heads having sizes which are equal to or less in size than the maximum body size are provided to the machining unit, and a seal member is mounted on an inner edge of each head cover to come into contact with the outer peripheral surface of the respective machining head.

6. A machine tool according to claim 5 , wherein guide rails are mounted immediately on the upper surface of the bed and the Z-axis saddle of the machining unit is mounted on the guide rails.

7. A machine tool according to claim 1 , wherein the machining head is mounted to be able to reciprocate in a lateral X-axis direction or a vertical Y-axis direction, a shield cover is mounted on the machining unit to shield the machining head and to allow reciprocatory movements of the machining head in the X-axis direction or the Y-axis direction, and an outer peripheral surface of an annular frame constituting the shield cover is brought into sliding contact with an inner peripheral surface of the seal member on a side of the opening window in a state, in which the machining head is moved into the machining region from a tool exchange position within the machine region.

8. A machine tool according to claim 7 , wherein the compartment cover comprises a roll cover.

9. A machine tool according to claim 1 , wherein the compartment cover comprises an arch-shaped support frame provided upright in a predetermined position on the bed, and an extensible cover mounted inside the support frame to be able to reciprocate together with the seal member in a lateral X-axis direction or a vertical Y-axis direction, and wherein interlocking unit is provided between the machining unit and the extensible cover to move the extensible cover and the seal member in the X-axis direction or the Y-axis direction so that the machining head corresponds to the seal member as viewed in a Z-axis direction when the machining unit is moved in the X-axis direction or the Y-axis direction.

10. A machine tool according to claim 9 , wherein the compartment cover comprises a roll cover.

11. A machine tool according to claim 1 , wherein guide rails are mounted immediately on the upper surface of the bed and the Z-axis saddle of the machining unit is mounted on the guide rails.

12. A machine tool according to claim 11 , wherein the seal member comprises a scraper having a seal lip and has a tip end thereof directed toward the machining region.

13. A machine tool according to claim 1 , wherein the seal member comprises a scraper having a seal lip and has a tip end thereof directed toward the machining region.

14. A machine tool according to claim 13 , wherein the machining head comprises a multi spindle head provided with a plurality of tools.

15. A machine tool according to claim 1 , wherein the machining head comprises a multi spindle head provided with a plurality of tools.