JP2525985Y2 - Tailstock - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION INDUSTRIAL APPLICATION The present invention relates to a tailstock suitable for a rigid work piece.

2. Description of the Related Art For example, when machining a rigid workpiece such as a thin crankshaft, the use of a hydraulic tailstock causes the workpiece to bend as shown in FIG. For this reason, a tailstock is used to prevent the workpiece from bending.

Problems to be Solved by the Invention When a tailstock is used, it is necessary to operate the work while checking the tailstock thrust for each work piece, and it takes a long operation time and the thrust varies. In addition, there is a problem that automation cannot be handled.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide a tailstock that can be automated without bending a workpiece having a small rigidity. Is what you do.

Means for Solving the Problems In order to achieve the above object, the present invention provides a pressure air ejection passage from the center of a tailstock sensor, and provides means for detecting a differential pressure between the passage pressure and a set pressure. The clamping means is provided, and the clamping means is actuated based on a signal at a time when the tail pressure thrust of the differential pressure detecting means is substantially zero.

The work is transported between the chuck and the tailstock center, the tailstock shaft is advanced by hydraulic pressure, and when the tailstock center is desired in the center hole of the work, the air ejected from the center nozzle is gradually reduced and the center taper surface Contact the periphery of the center hole, the pressure in the tailstock shaft passage matches the set pressure or a predetermined pressure difference, a signal is output from the differential pressure detecting means, the tailstock advance is stopped, and the tailstock shaft is clamped. You.

Embodiment A description will be given below with reference to FIGS.

A hollow push shaft 2 is slidably inserted into a through hole of a tailstock main body 1 of a known lathe or grinder. A tailstock main shaft 5 is rotatably supported by bearings 3 and 4 in a through hole of the tailstock shaft 2, and a tailstock center 6 is fitted in a tape hole at the center end of the tailstock shaft 5. . An ejection nozzle is formed at the center of the tip of the tailstock center 6, and a pressure air passage 7 is bored at the center of the tailstock center 6 and the tailstock shaft 2.

The tail end of the tailstock body 1 has a cylinder 10 concentric with the tailstock shaft 2.
The protruding end of the piston rod 12 before the fitted piston 11 is screwed to the rear plate 13 of the tailstock 2. At the center of the protruding tip of the rear piston rod 14 of the piston 11, an air joint 17 connected to a pressure air source is attached, and communicates with a flow path 15 at the center of the piston rod 14, the piston 11, and the piston rod 12. . This channel 15 and tailstock spindle 5
Of the tailstock main shaft 5 via an air rotary joint 16 attached to the rear end thereof.

The tailstock main body 1 is provided with a through hole in a direction perpendicular to the tailstock shaft above the tailstock shaft 2.
Brake bushings 18 with central holes on both sides
a and 18b are inserted so as to be able to pinch the tailstock, and a cylinder body 19 is mounted concentrically with one brake bush 18a, and a piston rod 21 of a piston 20 fitted to this is fitted.
Penetrates through the brake bushings 18a and 18b.
The rod length can be adjusted with a double nut 22 at the outer end, and the movement of the piston 20 causes the brake bushings 18a, 18b
Are adjusted so as to securely clamp the tailstock shaft 2.

The flow path 26 of the air connection 17 is connected to the pressure air source via the orifice 27 of the differential pressure detector 25, so that the flow path of the pressure air from the pressure air source 25 is branched into the orifice 27 in the differential pressure detector 25. The orifice 28 is released to the atmosphere through a variable throttle 29, and the connection point of the orifice 28 and the variable
Is connected to a differential pressure amplifier 30 that outputs a coincidence signal by a differential pressure switch. And orifice 2
8, a pressure gauge 31 for detecting a differential pressure is provided at a connection point of the variable throttle 29.

Hydraulic tailstock cylinder 10 front chamber flow path 35, rear chamber flow path
Reference numeral 36 is connected to a hydraulic pressure source via a four-port three-position switching solenoid valve 37 and to a tank via a sequence valve 38.

Further, the front and rear chambers of the brake cylinder 19 are connected to a hydraulic pressure source via a four-port two-position switching solenoid valve 39.

 The operation of the present invention thus configured will be described.

First, a reference differential pressure is set in the variable throttle 29 of the differential pressure detector 25. For example, a thin object crankshaft W having a small rigidity to be processed is transported between the spindle chuck and the center 6,
The electromagnetic switching valve 37 is switched to one position. The pressurized oil is sent from the line 36 to the rear chamber of the cylinder 10, and the tailstock 2 is advanced to grip the workpiece. When the tip of the tailstock center 6 is inserted into the center hole of the workpiece and the air ejected from the center of the tailstock center 6 is closed by the contact between the center taper surface and the center hole peripheral edge and the pressure set value in the passage 26 matches or is set. When the pressure and the constant differential pressure become equal to each other, the differential pressure switch of the differential pressure amplifier 30 operates to operate the electromagnetic switching valve 37.
At the II position, the pressure oil in and out of the switching cylinder 10 is stopped and the electromagnetic switching valve 39 is switched to the II position to switch the brake bushes 18a, 18
Pull b together and clamp. The bending amount of the workpiece in this state is measured, and the variable aperture 29 is adjusted until the bending amount becomes almost zero.

When the adjustment before machining is completed in this way, the tailstock shaft 2 is advanced by setting the electromagnetic switching valve 37 to the I position in accordance with the workpiece transfer signal. The moment the tailstock 6 is in the center hole of the workpiece W and the center taper surface comes into contact with the periphery of the center hole, the pressure in the flow path 26 matches the set pressure, a match signal is output from the differential pressure detector 25, and electromagnetic switching is performed. The valve 37 is switched to the II position to lock the pressure oil in the cylinder as the neutral position, and the electromagnetic switching valve 39 is switched to the II position to draw the brake bushes 18a and 18b and clamp the tailstock 2. The outer diameter is cut by a cutting tool or the outer diameter is ground by a grindstone while the thrust is substantially zero.

Effects As described in detail above, the present invention has the following effects.

The work is supported in a state where the tailstock thrust is almost zero, and even a work having a small rigidity does not bend, so that high-precision machining can be performed and automation can be realized by fully automatic operation.

[Brief description of the drawings]

1 is an explanatory view of the tailstock of the present invention, FIG. 2 is a sectional view taken along line AA of FIG. 1, FIG. 3 is an air / hydraulic circuit diagram, and FIG. It is a holding | maintenance state diagram of a small workpiece. 1 tailstock body, 2 tailstock shaft 5 tailstock spindle, 6 tailstock center 10, 19 cylinder 11, 20 piston 16 air rotary joint 18a, 18b Brake bush 25… Differential pressure detector 27,28… Orifice, 29… Variable throttle 30 …… Differential pressure amplifier

Claims (1)

(57) [Scope of request for utility model registration] 1. A tailstock that hydraulically moves a tailstock center, wherein a pressurized air ejection passage is provided from the center of the tailstock center,
The pressure air branches off from the first orifice of the passage connected to the ejection passage and opens a variable throttle following the second orifice to the atmosphere to detect a differential pressure on the outlet side of the first and second orifices. A pressure detecting means is provided, and the hydraulic circuit of the tailstock center includes clamp means for a tailstock shaft operated by another hydraulic circuit. The variable throttle is adjusted in advance, and the tailstock of the differential pressure detecting means is adjusted. A tailstock, wherein the clamp means is operated based on a differential pressure coincidence signal output at a time when the thrust is substantially zero.