JPH0314285Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to an internal grinding wheel shaft quill suitable for internal grinding, particularly when machining small-diameter deep holes.

Prior Art In internal grinding, when drilling a deep hole with a relatively small diameter, a suitable internal grinding wheel shaft quill made of a thin and long steel material is used. For example, as disclosed in Japanese Patent Application Laid-Open No. 61-76251, a method is known in which a vibration-isolating shaft member is obtained by dividing a core material into a plurality of parts, joining them together via a viscous material, and inserting them into a shell. .

Problems that the invention aims to solve: Conventional thin and long steel quills lack rigidity, and the tip bends due to its own weight, including the grindstone, resulting in unbalance, which causes dangerous speeds, and limits the upper limit.
Normally, the rotational speed of the quill is influenced by the outer diameter of the whetstone, and the smaller the diameter of the whetstone, the higher the speed of rotation and unless the outer peripheral speed of the whetstone is maintained, efficient and appropriate machining cannot be achieved. On the other hand, if the quill diameter is small, the critical speed is low and the rotation cannot be increased. Therefore, work is carried out within the range where safe machining can be continued at the expense of efficiency. The shaft member in which the plurality of core materials described above are inserted into the shell through a viscous material lacks rigidity, and if the core materials become eccentric during high-speed rotation, the amount of eccentricity will be further amplified and the imbalance will cause dangerous speeds. may decrease.

Means for Solving the Problem An internal grinding wheel shaft quill 23 is attached to the tip of the internal grinding wheel shaft 16 and has an internal grinding wheel 26 fixed to the tip.
In this embodiment, an outer cylindrical member 25 made of a ceramic material is joined over the entire outer periphery of a central member 24 made of a steel material.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings. In the known internal grinding machine, a spindle swivel base 2, which has a turning center hole on the upper surface and a circular T-groove cut around it, is fixed on a protruding wall 1a provided on the left side of a bed 1, and the spindle turns. A headstock 4 having a pivot shaft projecting downwardly is rotatably fixed on the base 2. A main spindle 5 is rotatably supported on the main spindle 4, a chuck 6 is fitted to the tip of the main spindle 5, a pulley is fixed to the other end, and rotation is transmitted by a main spindle motor 7 via a belt. A table 8 is mounted on a sliding guide surface cut in the direction of the main axis on the upper surface of the bed 1 so that its left end passes under the main shaft swivel base 2 and is movable over the entire upper surface of the bed by the operation of a hydraulic cylinder (not shown). has been done. A lower stand 9 having a sliding guide surface perpendicular to the spindle 5 on its upper surface is fixed on the table 8, and an upper stand 10 is placed on the sliding guide surface of the lower stand 9 so as to be slidable in a direction perpendicular to the spindle. A round handle 12 fitted to the front end of the screw 11 performs cutting with the grindstone. Upper stand 10
An internal grindstone shaft unit 14 is fixed on the top in the same direction as the main shaft. The internal grinding wheel shaft 16 is mounted by a plurality of bearings in the center hole of the frame 15 of the internal grinding wheel shaft unit 14.
A blind hole 16a is bored in the center of the tip of this inner grinding wheel shaft 16, and a female thread 16b is carved in the back following the straight part 16c, and two parallel to the outer periphery near the tip. A flat spanner hook is cut out, and a pulley 17 is fitted to the rear end. A motor base 18 having a T-groove on the upper surface is fixed on the upper stand 10, and the motor base 1
An internal grinding wheel shaft motor 19 is fixed on top of the internal grinding wheel shaft motor 19, and a pulley 20 is fitted to the output shaft of the internal grinding wheel shaft motor 19, and the rotation of the motor is transmitted to the internal grinding wheel shaft 16 via a belt. Ru. Inner grinding wheel shaft quill 23
is made of two different materials: a quill base 24 made of steel and a guard collar 25 made of ceramic. A large diameter portion 24c that is smaller in diameter than the outer diameter of the inner grinding wheel shaft 16, and a small diameter portion 24d that is thinner and longer than that.
The stepped shaft quill base 24 consists of a large diameter portion 24
A threaded straight shank 24a is provided at the tip of c, and a bolt hole 24b for attaching a grindstone is bored at the tip of the small diameter portion 24d.

The guard collar 25 has a stepped sleeve shape that covers the entire outer circumference of the stepped shaft of the quill base 24, and a large diameter portion 25a that covers the large diameter portion 24c of the quill base has the same diameter as the outer diameter of the internal grinding wheel shaft 16, and a small diameter portion 25a that covers the large diameter portion 24c of the quill base. The portion 25b is made to have the same diameter as the minimum usable diameter of the grindstone. Furthermore, the length of the small diameter portion 25b is formed to match the length of the grinding hole, and the quill base 24 and the guide collar 25 are bonded and integrated into one piece. The straight shank 24a with the screw 24e of the internal grinding wheel shaft quill 23 is fitted into the hole 16a of the internal grinding wheel shaft 16 without any gap, and is screwed together with the screw 16b to be fastened accurately on the same center line. and screws 16b, 24e
is a screw in a direction that can be tightened by rotation of the inner grinding wheel shaft 16. The internal grinding wheel 26 has a center hole, and is concentrically fastened to the bolt hole 24 at the tip of the internal grinding shaft quill 23 by a tightening bolt 27 with a washer 28 interposed therebetween. Furthermore, instead of a grindstone, it can also be used as a tool holding shaft to which a milling cutter or cutting tool is fixed.

Operation: A workpiece having a small diameter and long drilled hole is gripped by the chuck 6 fitted on the tip of the main spindle 5.
The internal grinding wheel shaft unit 14 stops at the retreat end set on the right side of the bed 1, and the internal grinding wheel shaft quill used for pre-processing, which is fitted to the tip of the internal grinding wheel shaft 16, is removed and removed from the small diameter long hole. The threaded straight shank 24a of the inner grinding wheel shaft quill 23 with ceramic guard is inserted into the tip hole 16a of the inner grinding wheel shaft 16, and the threaded portions 16b and 24e are screwed together and fixed. The internal grinding wheel shaft quill 23 with a ceramic guard is lightweight and strong, so the tip part is less deflected by its own weight and has a high critical speed. while the workpiece is rotated at relatively low speed by the spindle motor 7. Internal grinding wheel shaft unit 14
The inner grinding wheel 2 is fixed to the tip of the inner grinding wheel shaft 16 which rotates at high speed as the table 8 is moved toward the main spindle at a rapid speed by the operation of a hydraulic cylinder (not shown).
6 stops just in front of the workpiece, is switched to traverse speed, is inserted into the machined hole of the workpiece, and is turned back and reciprocated at a position where the edge of the grindstone slightly protrudes from both ends of the machined hole. Traverse feed is carried out, the circular cutting handle 12 is turned to make a cut, the inner grinding wheel 26 is pressed against the machined hole, and grinding is started, and the grinding is continued until a predetermined dimension is reached. After the machining is completed and the internal grinding wheel 26 is pulled out of the workpiece hole, the speed is switched to rapid traverse speed and it stops at the retreat end, and the internal grinding wheel shaft 16 remains rotated until it is ready for replacement of the workpiece. and then moved to the spindle side again.

Effects Ceramic material, which has a lower specific gravity and greater rigidity than steel material, is used as the guard collar, so compared to conventional internal grinding wheel shaft quills made only of steel material, it has sufficient rigidity and is light in weight, so it can be easily used by its own weight. Since an internal grinding wheel shaft with less deflection of the quill tip is obtained, the critical speed range due to unbalance is increased, high-speed rotation is possible, and even when machining small diameter long holes, the grinding speed can be approached to the ideal grinding speed, improving grinding efficiency. Furthermore, the synergistic effect of the combination of different materials prevents vibrations and reduces the occurrence of chatter.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the present invention, and FIG. 2 is a diagram of an internal grinder. 14... Inner grinding wheel shaft unit, 16... Inner grinding wheel shaft, 23... Inner grinding wheel shaft quill, 24... Quill base, 25... Guard collar.

Claims (1)

[Scope of utility model registration request] In an internal grinding wheel shaft quill that is attached to the tip of an internal grinding wheel shaft of an internal grinding machine or a universal grinding machine, and an internal grinding wheel is fixed to the tip, an outer cylinder member made of a ceramic material is provided over the entire outer periphery of a central member made of a steel material. An internal grinding wheel shaft quill characterized by being joined.