JPS593763Y2 - Lathe tailstock tailstock actuating device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a device for moving the central shaft of a lathe in the axial direction, which rotates at high speed, can freely move forward and backward in the axial direction, and can be slightly displaced in the radial direction.

Conventionally, when moving a high-speed rotating shaft attached to the center stand of a lathe back and forth in the axial direction, a piston was attached to the rear end of the center shaft, and the cylinder on which this piston slides was moved to the rear end of the center stand. There is a device that is attached to a cylinder and moves the piston and the heart axis in the axial direction using compressed air supplied to the cylinder.

In order to maintain airtightness between the outer periphery of the piston and the cylinder, conventional devices use a backing as a piston ring on the piston.When the piston attached to the center axis rotates at high speed, the backing is attached to the inner wall of the cylinder. Since there is a problem in terms of heat generation and wear and tear of the backing due to sliding, the piston is structured so that it does not come into contact with the inner wall surface of the cylinder, and the compressed air supplied to the cylinder is distributed between the outer periphery of the piston and the inner wall surface of the cylinder. It is now possible to pass through the gap between the

In order to allow minute radial displacement of the heart axis, or from the viewpoint of machining accuracy of the component parts, the gap mentioned above could not be made very small, so compressed air leaked through this gap, reducing its consumption. It had the disadvantage of being large.

In addition, since the tailstock spindle rotates at high speed and can freely move back and forth in the axial direction, it is necessary to use a non-contact type, complicated and expensive device to detect the end of the spindle stroke, which is necessary when automating the tailstock mechanism. There are disadvantages in that a detection device is required and it is difficult to adjust the stroke detection position.

In view of the above, this idea was developed for a lathe tailstock shaft that rotates at high speed, can move back and forth in the axial direction, and is expected to undergo minute displacement in the radial direction. It is an object of the present invention to provide a shin shaft drive device that can reduce compressed air consumption compared to other devices, and that can easily detect the end of the shin shaft stroke, which is required when automating the shin function, with a simple structure. This is the purpose.

Next, this invention will be explained based on embodiments shown in the drawings.

The main body 2 of the Shinshindai 1 of the lathe slides on a bed (not shown) and has a base D fixed to the bed at an arbitrary position.
is attached to the top of the.

The Shinshin stand main body 1 has a shaft hole 2a, and the Shinshin shaft 3 is rotatably supported by a front static pressure journal bearing 4 and a rear static pressure journal bearing 5 provided in the shaft hole 2a.

The Shinshin shaft 3 has a fixed center 6 fitted in the shaft center at the end of the main shaft (not shown) of the lathe, and a shaft hole 2a in the other end.
A disk-shaped rotating piston 7 that slides on an appropriate number of bolts 8
It is attached by.

This rotary piston 7 has a dish-shaped recess 7b formed on its rear end surface (on the opposite side from the cardiac axis 3), leaving a ring-shaped edge 7a.

The cylinder 9 has a shaft hole 9a in its shaft center portion in which a rod portion 10a of an idle piston 10, which will be described later, slides therein in an airtight manner.

The cylinder 9 aligns the axis of its shaft hole 9a with the axis of the shaft hole 2a of the Shinshindai main body 2, and the front end of the cylinder 9 is airtightly fitted into the shaft hole 2a, so that the cylinder 9 is attached to the rear end of the Shinshindai main body 2. It is attached with bolts (not shown).

The cylinder 9 has a recess 9b formed in its front end surface.

The cylinder 9 has a supply path 11 for supplying compressed air from the outside, and this supply path 11 communicates with the recess 9b.

The idle piston 10 has a piston portion 10 at its front end.
b, and this piston portion 10b is located between the front end of the cylinder 9 and the rear end of the piston 7.

This piston portion 10b is connected to the shaft hole 2 of the Shinshindai main body 2.
a, it can be slid airtight through the backing 12.

The idle piston 10 has two passages 13 and 14 in the axial direction, the first passage 13 communicates with the recess 9b at the front, and the rear part communicates with the throttle valve provided at the rear end of the second passage 14. It is connected to 15.

The second passage 14 has an opening 14a at its front end in the front end face of the piston portion 10b of the idle piston 10.

Here, the throttle valve 15 has a cylindrical body 16 as shown in FIG.
and valve stem 17.

The cylindrical body 16 has a tapered hole 16a in the front part, and a passage 16b communicating with the first passage 13 behind the tapered hole 16a.
The tapered hole 16 a of the cylindrical body 16 communicates with the second passage 14 .

The valve stem 17 has a tapered front portion 17a, and is screwed into the cylinder body 16 by a threaded portion 17b provided at the rear.

The throttle valve 15 increases or decreases the gap between the tapered hole 16a of the cylinder body 16 and the tapered part 17a of the valve stem 17 by moving the valve stem 17 back and forth with a screw, thereby increasing or decreasing the gap between the first passage 13 and the second passage. The flow path resistance of compressed air flowing to 14 is increased or decreased.

A bypass valve 18 is attached to the idle piston 10 in a hole 10C that passes through the piston portion 10b in the front and rear directions (see FIG. 3).

This bypass valve 18 includes a valve 19 that opens and closes a valve seat 10d provided in the front part of the piston part 10b, and a valve 19 that opens and closes the valve seat 10d provided in the front part of the piston part 10b.
There is a spring 20 that is brought into pressure contact with the valve seat 10d to close the valve seat 10d.

When the bypass valve 18 is closed, the rear end of the valve 19 protrudes rearward from the piston portion 10b.

A ring member 21 on which the Shinshin shaft 3 slides is fitted into the shaft hole 2a of the Shinshin shaft 2 at the rear of the rear static pressure journal bearing 5, and when the Shinshin shaft 3 is at the rearward end, the ring member 21 slides. A predetermined distance l is provided between the rear end of the rotary piston 21 and the front end of the rotary piston 7, and this distance l is the distance over which the cardiac axis 3 can move.

The ring member 21 has a front air chamber A formed by the outer peripheral surface of the cardiac axis 3, the shaft hole 2a, the inner peripheral surface, the rear end surface of the ring member 21, and the front end surface of the rotary piston 7, and an external air passage 22. A passage 21a is provided to communicate with the.

Here, when the center axis 3 is located at the backward end and the rotary piston 7 attached to the center axis 3 presses the idle piston 10 against the cylinder 9, the rotation piston 7 and the piston portion 10b of the idle piston 10 are in contact with each other. The effective area EB1 of the intermediate air chamber B formed between the concave portion 7 of the piston 7
The effective area EC1 of the rear air chamber C formed between the cylinder 9 and the piston portion 10b of the idle piston 10 is the area b1 perpendicular to the axis of the piston 7 of the cylinder 9. A value C1 is obtained by subtracting the cross-sectional area of the rod portion 10a of the idle piston 10 from the area perpendicular to the axis of the idle piston 9a.

Then, the piston portion 10b of the idle piston 10 is separated from the cylinder 9, and the piston 7 is moved away from the idle piston 1.
When it is separated from the piston part 10b of 0, the intermediate air chamber B
The effective area EB2 is the area obtained by adding the surface area b2 of the edge 7a to the area b□ of the recess 7b, that is, b, +b2,
Also, the effective area EC2 of the rear air chamber C is the idle piston 1.
From the cross-sectional area of the piston part 10b of 0, the rod part 10a
The value C2 is obtained by subtracting the cross-sectional area of .

Then, b1+b2>b engineering and C2>CI.

The effective area EA of the front air chamber A is a value a1 obtained by subtracting the cross-sectional area perpendicular to the axis of the cardiac axis 3 from the effective area b1+b2 of the rotary piston 7.

The cylinder 9 is provided with an oil supply port 23 for supplying pressure oil from the outside, and the pressure oil supplied from this oil supply port 23 has the same shape as the throttle valve 15 and has an appropriate flow resistance. After passing through a set appropriate number of throttle valves 24, the front static valve is It is supplied to the pressure journal bearing 4 and the rear hydrostatic journal bearing 5.

Note that the pressure oil supplied to the front and rear static pressure journal bearings 4 and 5 flows out from these bearings 4 and 5, and then flows through oil passages 2C...2C provided in the Shinshindai main body 2. The oil accumulates in the tank 2d and is discharged from the oil tank 2d to the outside.

A non-contact type sealing device 25 that surrounds the Shinshin axis 3 is provided at the front end of the Shinshindai main body 2.

This sealing device 25 includes an inner aerostatic thrust bearing 26 fitted into the front end of the shaft hole 2a of the Shinshindai main body 2, an outer aerostatic pressure thrust bearing 27 attached to the front end of the Shinshindai main body 2; A ring 28 is fitted between the outer hydrostatic thrust bearing 27 and the inner hydrostatic thrust bearing 26 and is inserted into the outer side of the shinshaft 3.

The inner diameters of the inner hydrostatic thrust bearing 26 and the outer hydrostatic thrust bearing 27 are slightly larger than the outer diameter of the shinshaku 3.

The ring 28 can slide airtightly in the axial direction with respect to the Shinshin shaft 3, and an inner hydrostatic thrust bearing 26 and an outer hydrostatic thrust bearing 27 are provided on both sides and the outer circumference of the ring 28.
A gap is formed between the two.

Then, when compressed air is supplied from the conduit 29, this compressed air is passed through small holes (not shown) forming an appropriate number of self-control throttles provided in the outer hydrostatic thrust bearing 27 and the inner hydrostatic thrust bearing 26, respectively. When the front and rear sides of the ring 28 are ejected and the Shinshinshaft 3 moves in the front-rear direction relative to the Shinshindai main body 2, the ring 28 and both static pressure thrust bearings 26.2
7, a space is maintained by compressed air, and the pressure oil from the front hydrostatic bearing 4 side is prevented from flowing out.

The idle piston 10 is located at the rear end of the rod portion 10a.
A bracket 30 is attached that projects downward from the rod portion 10a.

A bar 31 made of a round bar is attached to the bracket 30 parallel to and below the rod portion 10a.

The front end of the bar 31 is located in a hole 9d provided in the cylinder 9, and is supported so as to be movable in the front-back direction by a bearing 32 fitted into the rear end of the hole 9d.

Two dogs 33 and 34 are fitted into the bar 31, and the dogs 33 and 34 can be fixed to the bar 31 at any position.

Below the bar 31, a microswitch support plate 35 parallel to the bar 31 is attached to the rear end of the cylinder 9 by bolts 36.

Two microswitches 37 and 38 are attached to the microswitch support plate 35, which can be fixed at any position on the support plate 35, and which are operated by dogs 33 and 34.

Next, the operation of this embodiment will be explained.

When compressed air is supplied from the supply path 11 when both the center axis 3 and the idle piston 10 are near the retreat end and the bypass valve 18 is closed, the compressed air is supplied to the piston portion 10b of the idle piston 10 and the cylinder 9. (See Figure 4)
, the throttle valve 1 via the first passage 13 of the idle piston 10
After the pressure is lowered due to the flow path resistance of 5, it flows into the intermediate air chamber B through the second passage 14, passes through the gap between the outer circumference of the rotary piston 7 and the shaft hole 2a of the main body 2, and then flows into the front part. The air flows into the air chamber A.

In this way, the compressed air that has flowed into the front air chamber A flows out into the atmosphere through the passage 21a of the ring member 21 and the air passage 22.

In the above compressed air flow, the compressed air enters the second passage 1
4 into the intermediate air chamber B, the rotary piston 7 is pushed forward by the pressure of the compressed air within the intermediate air chamber B.

At this time, the product C2XP3 of the effective area C2 of the rear air chamber C and the compressed air pressure P3 acting on this rear air chamber C is the product C2 Product (b1+b 2) X P 2
If the throttle valve 15 is adjusted to be larger, the pressing force acting on the compressed air piston portion 10b in the rear air chamber C will act on the compressed air rotating piston 7 in the intermediate air chamber B. This becomes larger than the pressing force, and the idle piston 10 also moves forward.

Therefore, pressurized oil is supplied from the oil supply port 23 to the front and rear static pressure journal bearings 5 and 6, and the Shinshin shaft 3 is
It supports the bearings 5.6 at its axial center in a non-contact state, and supplies compressed air from the conduit 29 to the sealing device 25 to prevent pressure oil from flowing out from the Shinshindai main body 2 to the outside. After preventing this, when compressed air is supplied from the supply path 11 to the rear air chamber C, both the cardiac axis 3 and the idle piston 10 move forward.

Then, when the fixed center 6 fitted to the Shinshin shaft 3 hits a workpiece (not shown) attached to the lathe main shaft,
Shinshin Axis 3 stops.

When the cardiac axis 3 stops, the fixed center 5 has an intermediate air chamber B.
The pressure of the compressed air inside generates a shinshin force, and the shinshin shaft 3 rotates together with the workpiece.

On the other hand, even if the cardiac axis 3 stops, compressed air is still acting on the rear air chamber C, so the idle piston 10 continues to move forward and approaches the rotary piston 7, and the edge 7a of the rotary piston 7 and the idle piston 10 continue moving forward. The gap t (see FIG. 4) between the piston 10 and the piston portion 10a is reduced.

Therefore, the amount of compressed air leaking from the outer circumference of the rotary piston 7 to the front air chamber A decreases, and the pressure P2 in the intermediate air chamber B increases.

When the total pressing force of the compressed air in the intermediate air chamber B and the total pressing force of the compressed air in the rear air chamber C acting on the piston part 10b become the same, the idle piston 10 is moved in front of the piston part 10b. The air pressure acting on the rear surface is balanced and it stops.

If the flow path resistance of the throttle valve 15 is adjusted so that the gap t becomes minute when the idle piston 10 stops, the gap t is kept at a minute gap.

Therefore, the amount of compressed air that passes through the gap t and escapes from the outer periphery of the rotary piston 7 to the front air chamber A during lathe processing is limited, and its consumption is saved.

Furthermore, when the center shaft 3 is displaced in its axial direction in the tailstock state, the idle piston 10 follows and moves so that the gap t becomes a constant gap.

Next, in order to retreat the heart shaft 3 from the tailstock state, compressed air is supplied from the air passage 22 to the front air chamber A, and the supply passage 11 is opened to the atmosphere.

When the supply path 11 is opened to the atmosphere, the compressed air in the intermediate air chamber B and the rear air chamber C flows out from the supply path 11 to the atmosphere, and the intermediate air chamber B and the rear air chamber C become atmospheric pressure.

Note that at this time, the bypass valve 18 is in a closed state.

If the gap t between the rotary piston 7 and the piston portion 10b of the idle piston 10 is small and the rotary piston 7 and the idle piston 10 are in close contact, the compressed air supplied to the front air chamber A will be transferred to the intermediate air chamber. Since the compressed air in the front air chamber A cannot flow into the air chamber A, the rotary piston 7 moves rearward, causing the cardiac axis 3 and the idle piston 1 to move backward.
0 goes backwards.

If the above-mentioned gap t is not in a tight state, the front air chamber A
The compressed air supplied to the front air chamber A passes through the gap on the outer circumference of the rotary piston 7, enters the intermediate air chamber B, and passes through the second passage 14, the throttle valve 15, the first passage 13, and the rear air chamber C. After that, it flows out from the supply path 11 into the atmosphere.

In this case, because of the throttle valve 15, the compressed air pressure P2' in the intermediate air chamber B is higher than the compressed air pressure P'a in the rear air chamber C, and the pressure difference P2'P3' between the plane compressed air is large. When the difference P't-P'2 between the compressed air pressure PI' in the air chamber A and the compressed air pressure P'2 in the intermediate air chamber B is small, the total pressing force of the compressed air acting on the front surface of the rotary piston 7 (P' −
P2 x a becomes smaller than the total pressing force P2' x (b 1 + b 2) of compressed air acting on the rear surface of the rotary piston 7, and the heart axis 3 does not move back, but only the idle piston 10 moves back. It is in.

When the idle piston 10 reaches the backward end, the rear end of the valve 19 of the bypass valve 18 comes into contact with the surface of the recess 9b of the cylinder 9, moves forward against the pressing force of the compression spring 20, and opens.

Therefore, the intermediate air chamber B and the rear air chamber C are connected to the throttle valve 15.
The pressure in the intermediate air chamber B and the pressure in the rear air chamber C both become atmospheric pressure, and the cardiac axis 3 retreats.

As is clear from the above description, the idle piston 10
does not rotate even during tailstocking of the center shaft 3, but simply moves in the axial direction, so slide the dogs 33 and 34 on the bar 31 attached to the idle piston 10 and fix them at appropriate positions. By doing so, Dog 34
When the dog 33 comes into contact with the limit switch 38, the retreat end of the heart axis 3 can be detected, and when the dog 33 comes into contact with the limit switch 37, the forward end of the heart axis 3 can be detected.

As described above, this invention is a lathe tailstock that supports a spindle in a shaft hole of a spindle main body so as to be rotatable and movable in the axial direction, and the shaft hole communicates with an external air passage. A rotating piston with a front air chamber formed in the front and fixed to the rear end of the cardiac axis, a piston part and a rod part, and the piston part is airtight with respect to the shaft hole of the cardiac axis at the rear of the rotating piston. A cylinder that inserts the rod part of the idle piston into the inserted idle piston and the shaft hole provided in the shaft center, and is attached to the rear part of the Shinshindai and airtightly covers the rear end of the shaft hole of the Shinshindai. An intermediate air chamber is formed between the rotary piston and the idle piston, and a rear air chamber is formed between the idle piston and the cylinder and communicated with an external compressed air passage, and the rear air chamber is throttled. The rotary piston is provided with means for minimizing the outflow of air from the intermediate air chamber to the front air chamber when the rotary piston and the idle piston are close to each other, and the idle piston is By providing means for detecting the stroke end of the cardiac axis, compressed air is supplied to the rear air chamber to generate a cardiac force on the cardiac axis, and when the rotating piston and the idle piston approach, the intermediate air chamber detects the stroke end of the stroke end. Since the amount of compressed air that flows out is extremely small, the amount of compressed air consumed can be reduced. Also, by providing means for detecting the end of the stroke of the heart axis on the idle piston that does not rotate during the movement of the heart axis, Stroke end detection can be facilitated to facilitate automation of the tailstock function.

[Brief explanation of drawings]

The figures show one embodiment of this invention; Fig. 1 is a vertical cross-sectional view of the Shinjindai, Fig. 2 is an enlarged view of the throttle valve section in Fig. 1, and Fig. 3 is an enlarged view of the bypass valve section in Fig. 1. The enlarged view, FIG. 4, shows the rotary piston, idle piston, and cylinder of FIG. 1 separated from each other. 1...Shinjindai, 2...Shinjindai main body, 2
a...Shaft hole, 3...Shinshin axis, 7...
...Rotating piston, 9...Cylinder, 9a.
...Shaft hole, 10...Idle piston,
10a...Rod part, 10b...Piston part, 13...First passage, 14...
2nd passage, 15... Crest valve, 18...
Bypass valve, 33.34...Dog, 37.3
8... Micro switch, A... Front air chamber, B... Intermediate air chamber, C... Rear air chamber.

Claims (1)

[Scope of utility model registration request] In a lathe shin-shin stand which supports a shin-shin shaft in a shaft hole of a shin-shin stand main body so as to be rotatable and movable in the axial direction of the shaft hole, a front air chamber communicating with an external air passage is formed in the front part of the shaft hole and the outer periphery is provided. a rotary piston fixed to the rear end of the shaft with a gap between the shaft hole and the piston, the piston having a diameter smaller than that of the piston; The rod part of the idle piston is airtightly inserted into the shaft hole provided in the shaft center part, and the rod part of the idle piston is airtightly inserted into the shaft hole provided in the shaft center part, and the rod part of the idle piston is attached to the rear part of the Shinshindai. A cylinder that airtightly covers the rear end of the shaft hole is provided, and an intermediate air chamber is formed between the rotary piston and the idle piston, and a rear air chamber that communicates with an external air passage is formed between the idle piston and the cylinder. In addition, a passage is provided for communicating this rear air chamber with the intermediate air chamber via a throttle, and when the rotating piston and the idle piston are close to each other on the outer peripheral surface of the idle piston side, the intermediate air chamber is connected to the front air chamber. The idle piston is provided with an edge that minimizes the air outflow to the idle piston, and the idle piston is provided with a bypass valve that communicates the intermediate air chamber and the rear air chamber when the piston is at the retreating end, and a device that detects the stroke end of the cardiac axis. A cardiac axis actuating device characterized by being provided with.