JPH0112884Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotation center that supports a workpiece in a machine tool such as a lathe.

Conventional rotation centers of this type have the rear part of the center shaft inserted into a center hole drilled in the front of the center body through a radial bearing, and the center shaft is radially bearing in the center body. A thrust bearing is interposed between the front part of the center shaft protruding to the front side of the center body and the front face of the center body, the center shaft is axially supported by the center body, and the thrust bearing is interposed between the front part of the center shaft and the thrust bearing on the front side of the center body. The center shaft is covered with a cap, and the front tip of the center shaft protrudes from the front end opening of the cap.

However, since the workpiece supported and attached to the rotation center of a machine tool is sprayed with a cooling liquid to remove machining heat, the cooling liquid flows through the front end opening of the cap and the center shaft loosely penetrating the rotation center. Enter the cap through the gap between the front parts of the cap.

Therefore, in the rotation center, the bearing of the center shaft deteriorates due to the coolant, and the life of the bearing of the center shaft is shortened.

Therefore, a waterproof seal is used at the rotation center to prevent the intrusion of the coolant, but increasing the degree of sealing of the waterproof seal increases the amount of frictional heat generated by the waterproof seal.

In addition, when the rotation center rotates the center shaft at high speed, the frictional heat generated by the center shaft bearing increases, and the center shaft bearing deteriorates quickly due to the frictional heat.

Moreover, if there is a lot of frictional heat in the rotation center, each member will be thermally deformed, and the rotation accuracy of the center shaft will decrease.

Although not the rotation center of a machine tool, a dust-proofing device was devised for the grindstone head of an internal grinder.

As disclosed in Japanese Utility Model Publication No. 40-33589, this dust-proofing device has a grinding wheel shaft unit inserted into the shaft hole of the grinding wheel head of an internal grinding machine via a ball guide, and the grinding wheel shaft protrudes forward. The grindstone shaft unit is configured to swing back and forth, and the grindstone fitted to the front end of the grindstone shaft of the grindstone shaft unit protrudes from the front end opening of the shaft hole of the grindstone head.

The whetstone head is provided with an air passage, and the outlet of the air passage is formed into an annular shape through which the whetstone shaft of the whetstone shaft unit passes, and is disposed in front of the front end opening of the shaft hole of the whetstone head.

However, in this dustproof device, air is ejected from the air outlet not only during internal grinding and grinding wheel correction, but also during removal of the workpiece.
During the removal of the workpiece, the power to blow out air from the air outlet of the air passage is wasted.

The purpose of the present invention is to solve the conventional problems as described above.

In this invention, the rear part of the center shaft is inserted into the center hole drilled in the front side of the center body via a radial bearing, the center shaft is radially bearing in the center body, and the center shaft is protruded from the front side of the center body. A thrust bearing and a spring are interposed between the front part of the center shaft and the front surface of the center body, and the center shaft is supported in the axial direction by the center body and is capable of retracting. A rotating center with a cap covering the thrust bearing and spring, and with the front tip of the center shaft protruding from the front end opening of the cap, which opens when the center shaft retreats and closes when the center shaft restores itself. A high-pressure air passage equipped with a valve is connected inside the cap, and when the center shaft retreats, air is blown out from the gap between the front end opening of the cap and the front part of the center shaft that freely passes through this, and the center shaft is This is a jet-flow type rotation center characterized by a configuration in which the jetting of air is stopped upon restoration.

In the jet-type rotation center of the present invention, when a workpiece is attached to the tip of the center shaft and the center shaft is moved backward, the valve of the high-pressure air passage is opened, and the front end opening of the cap and the center shaft loosely penetrating therethrough are opened. Air blows out from the gap between the front parts.

Furthermore, when the workpiece is removed from the tip of the center shaft, the center shaft moves forward and returns to its original position, the valve of the high-pressure air passage closes, and the blowing of air stops.

In the jet-type rotation center of the present invention, while the workpiece is attached to the tip of the center shaft,
Since air is blown out from the gap between the front end opening of the cap and the front part of the center shaft, the cooling liquid is prevented from entering the cap through the gap between the front end opening of the cap and the front part of the center shaft.

That is, deterioration of the center shaft bearing due to the cooling liquid is prevented, and there is no need to increase the degree of sealing of the waterproof seal.

In addition, in the jet-type rotation center of the present invention, air circulates within the cap while the workpiece is attached to the tip of the center shaft, so the frictional heat of the bearing is eliminated by the airflow. .

That is, deterioration of the bearing due to frictional heat is prevented, and deterioration of rotation accuracy of the center shaft due to thermal deformation of each member is also prevented.

Furthermore, in the jet-type rotating center of the present invention, no air is ejected while the workpiece is being removed from the center shaft, so the power for ejecting air is not wasted.

In addition, the high-pressure air path is equipped with a valve that opens when the center shaft moves back when the workpiece is attached, and closes when the center shaft returns to its original position when the workpiece is removed. No need to worry about opening and closing.

Next, embodiments of the present invention will be described.

The jet type rotation center of this example shown in FIGS. 1 to 3 has a center hole 4 bored at the axial position in the front end surface of a center body 1 having a head 3 connected to the front end of a taper shank 2. The rear part of the center shaft 5 is inserted into the center hole 4 of the main body, and the front large diameter part and the rear end small diameter part of the rear part of the center shaft 5 are respectively radially supported in the center hole 4 by radial bearings 6 and 7. A sliding tube 9 is slidably fitted on the outer periphery of a cylindrical portion 8 protruding from the front end surface of the center body 1, and a stepped portion formed on the inner periphery of the front portion of the sliding tube 9 protruding from the cylindrical portion 8 and the center hole 4
A thrust bearing 10 is fitted between the stepped portions of the front part of the center shaft 5 protruding from the center shaft 5, and a thrust bearing 10 is inserted into the front end surface of the center body 1 through a key hole 12 penetrated through a flange 11 provided around the outer periphery of the rear end of the sliding tube 9. At the same time, the protruding key 13 is slid into place, and the protruding front end of the helical spring 15 inserted into the spring hole 14 formed in the front end face of the center body 1 is brought into contact with the flange 11 of the sliding tube, thereby rotating the center shaft 5. The sliding tube 9 and the helical spring 15 are connected by the thrust bearing 10.
The center shaft 5 and the sliding tube 9 are arranged so as to be retractable against the helical spring 15, and the front side of the center body 1 is covered with a cap 16. It covers the front part of the center shaft 5 and the sliding tube 9 that protrude to the front side of the
The front end of the center shaft 5 protrudes from the front end opening of the center shaft 5 . A valve shaft 18 whose front end is fitted into the flange 11 of the sliding tube is inserted into the valve hole 17 formed in the front end surface of the center body 1, and the cylindrical shaft portion of the valve shaft 18 is inserted into the valve hole 17 with the small diameter of the valve hole 17. The helical spring 19 is fitted between the head of the valve stem 18 and the bottom of the valve hole 17, and the valve stem 1
8 is brought into contact with the rear stepped portion of the small diameter portion of the valve hole 17 via the O-ring 20, and a through hole 21 extending radially through the cylindrical shaft portion of the valve shaft 18 is connected to the small diameter portion of the valve hole 17. When the valve stem 18 retreats against the helical spring 19 due to the retreat of the sliding tube 9, the through hole 21 of the valve stem communicates with the bottom of the valve hole 17. passes through the through hole 21 of the valve stem and the inside of the cylindrical shaft part of the valve stem to the cap 1.
A hose joint 22 that communicates with the bottom of the valve hole 17 is attached to the circumferential surface of the head 3 of the center body, and a hose 23 connected to a high-pressure air source (not shown) is connected to the hose joint 22. The valves 17, 18, which are opened by the retreat of the center shaft 5.
High pressure air passages 23, 2 provided with 19, 20, 21
2, 17, 18, and 21 are connected inside the cap 16, and air can be blown out from the opening between the front end opening of the cap 16 and the front part of the center shaft 5 when the center 5 retreats.

In addition, in FIG. 1 and FIG. 3, 24 is a seal with a V-shaped cross section.

The jet type rotating center of this example is used by fitting the taper shank 2 of the center body into the work head of a machine tool and supporting the workpiece between the center shaft 5 and the center of the tail stock, as in the conventional product. However, during this use, when the center shaft 5 is pushed back by the work material, the sliding tube 9 and valve shaft 18 also move back, and the valve of the high pressure air path opens, causing the cap 16 to open. Air blows out from the opening between the front end opening and the front part of the center shaft 5. Therefore, cutting oil and chips are prevented from entering the cap 16 through the opening, and the frictional heat caused by the rotation of the center shaft 5 is eliminated by the airflow flowing inside the cap 16. Furthermore, after use, when the center shaft 5 moves forward and restores itself by removing the workpiece, the sliding tube 9 and valve shaft 18 similarly move forward and restore themselves, and the valve of the high-pressure air path closes. The air circulation and blowout will stop.

The jet type rotation center of this example has a high pressure air path.
Since a valve is provided that opens when the center shaft 5 moves back when the workpiece is attached, and closes when the center shaft 5 returns to its original state when the workpiece is removed, there is no need to open or close the high-pressure air passage. It is very convenient.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional side view of a jet type rotation center according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line -- in FIG. 1, and FIG. 3 is a sectional view taken along the line -- in FIG. 1: Center body, 4: Center hole, 5: Center shaft, 6: Radial bearing, 7: Radial bearing,
10: Thrust bearing, 15: Spiral spring, 16: Cap, 17: Valve hole, 18: Valve shaft, 21: Through hole,
22: Hose joint, 23: Hose.

Claims (1)

[Scope of claim for utility model registration] The rear part of the center shaft is inserted into the center hole drilled in the front of the center body via a radial bearing,
The center shaft is radially supported on the center body, and a thrust bearing and a spring are interposed between the front part of the center shaft protruding toward the front side of the center body and the front surface of the center body, and the center shaft is axially supported on the center body. The center body is equipped with a cap that covers the front part of the center shaft, the thrust bearing, and the spring, and a rotating center with the front tip of the center shaft protruding from the front end opening of the cap. A high-pressure air passage equipped with a valve that opens when the center shaft retracts and closes when the center shaft returns is connected to the inside of the cap, and when the center shaft retracts, the front end of the cap is opened and connected thereto. A jet-flow type rotation center characterized in that air is ejected from a gap between the front parts of a center shaft that has freely penetrated, and the ejection of air is stopped when the center shaft is restored.