JP2002066805A - Tailstock of machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To operate a tailstock by means of a simple arrangement which does not use a hydraulic cylinder nor a limit switch. SOLUTION: A tailstock body 2 is movably installed on the bed 1 of a lathe or the like and a tailstock spindle 3 is longitudinally movably supported on the tailstock body 2. The tailstock spindle 3 is provided with a tailstock center 4, a ball screw nut 5, and a dog 6. Rotation of an electric motor 7 is converted into the linear movement of the tailstock spindle 3 by a ball screw shaft 10 and the ball screw nut 5. A switching mechanism comprises a roller 12 engaging the dog 6; a lever 13; a rod 16; and a spring 17, etc. A clamping member 11 is switched to an unclamping position at the position of the rear end of the tailstock spindle 3 and is switched to a clamping position as the tailstock spindle 3 advances.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tailstock for a machine tool.

[0002]

2. Description of the Related Art Conventionally, in a tailstock of a lathe, a tailstock shaft is moved back and forth by a hydraulic cylinder, a position of the tailstock is detected by a limit switch, and the tailstock body is moved at a retreat end position of the tailstock. There is known a technique in which a hydraulic cylinder is clamped to a bed by another hydraulic cylinder, and the hydraulic cylinder is unclamped when the tailstock is advanced.

[0003]

However, according to the conventional tailstock, a hydraulic cylinder for driving the tailstock shaft,
A hydraulic cylinder for clamping the tailstock main body and a limit switch for detecting the position of the tailstock shaft are required, resulting in a problem that the configuration and control are complicated and the cost is high.

An object of the present invention is to provide a tailstock of a machine tool which can be operated with a simple configuration without using a hydraulic cylinder or a limit switch.

[0005]

In order to solve the above-mentioned problems, a tailstock according to the present invention comprises a tailstock body movably installed on a bed of a machine tool, and a tailstock body which moves back and forth. A tailstock shaft that is supported as possible, a tailstock center inserted at the front end of the tailstock shaft, a dog that is fixed to the tailstock shaft, and a linear motion that is installed on the tailstock body and performs tailstock motion A drive mechanism, a clamp member for clamping the tailstock main body to the bed, and an engagement member for engaging the dog.The clamp member is switched to the unclamping position at the retreat end position of the tailstock to advance the tailstock. A switching mechanism for switching the clamp member to the clamp position.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, a tailstock main body 2 is movably installed on a bed 1 such as a lathe. A tailstock shaft 3 is supported on the tailstock main body 2 so as to be able to move back and forth, a tailstock center 4 is removably inserted at its front end, a ball screw nut 5 is fitted at its rear end, and a dog is 6 is fixed.

An electric motor 7 having a built-in rotation detector and a brake is installed at the rear of the tailstock main body 2. The output shaft 8 of the electric motor 7 is connected to a ball screw shaft 10 via a coupling 9, and the ball screw shaft 10 is screwed to the ball screw nut 5. The ball screw nut 5 and the ball screw shaft 10 constitute a ball screw mechanism that converts the rotation of the electric motor 7 into the linear motion of the tailstock shaft 3.

A clamp member 11 for clamping the tailstock main body 2 to the bed 1 is disposed below the tailstock main body 2. Inside the tailstock main body 2, an engaging roller 12 that engages with the dog 6 and a pair of levers 13 are provided. The proximal end of the lever 13 is rotatably supported by the tailstock main body 2 by a pin 14, and the distal end of the lever 13 has an engaging roller 12.
And a driven roller 15 that comes into contact with.

An intermediate portion of the lever 12 is connected to the clamp member 11 by a rod 16, and the rod 16 is provided with a spring 17 for pressing the driven roller 15 against the engaging roller 12. A switching mechanism is constituted by members such as the engagement roller 12, the lever 13, the rod 16, the spring 17, and the like, and switches the clamp member 11 to the unclamping position (see FIG. 1) at the retreat end position of the tailstock shaft 3. As the push shaft 3 advances, the clamp member 11 is switched to a clamp position (see FIG. 2).

The tailstock constructed as described above has the following operational effects. The tailstock shaft 3 can be driven by one electric motor 7 without using a hydraulic cylinder, and the clamp member 11 can be switched between the clamp position and the unclamping position as the tailstock shaft 3 moves. The position of the tailstock shaft 3 can be accurately detected based on the output of the rotation detector of the electric motor 7 without using a limit switch, and a plurality of positions can be easily set.

The speed of the tailstock shaft 3 can be variously changed at any point by controlling the rotation speed of the electric motor 7. The thrust of the tailstock 3 can be easily adjusted using the torque management function (torque skip function) of the electric motor 7. By operating the brake of the electric motor 7 at the time of a power failure, the tailstock shaft 3 can be prevented from retreating and safety can be ensured.

It should be noted that the present invention is not limited to the above-described embodiment, and the shape of each part is not deviated from the scope of the invention, for example, by using another linear motion mechanism such as a hydraulic cylinder instead of the electric motor and the ball screw mechanism. It is also possible to change the configuration as appropriate and to embody it.

[0013]

As described in detail above, according to the tailstock of the present invention, the tailstock shaft is driven by the electric motor, and the clamp member is switched in accordance with the movement of the tailstock shaft. There is an excellent effect that the tailstock can be operated with a simple configuration that does not use a cylinder or a limit switch.

[Brief description of the drawings]

FIG. 1 is a sectional view of a tailstock showing one embodiment of the present invention.

FIG. 2 is a sectional view showing the tailstock in an operation state different from that of FIG. 1;

[Explanation of symbols]

1. Bed, 2 tailstock body, 3 tailstock shaft, 4
・ Tailstock center, 5 ・ ・ Ball screw nut, 6 ・ Dog, 7 ・ ・ Electric motor, 10 ・ ・ Ball screw shaft, 11 ・
Clamping member, 12 engaging roller, 13 lever, 16 rod, 17 spring.

Claims (1)

[Claims] 1. A tailstock main body movably installed on a bed of a machine tool, a tailstock shaft movably supported by the tailstock main body, and a center inserted into a front end of the tailstock shaft. A dog center fixed to the tailstock shaft, a drive mechanism installed on the tailstock main body for linearly moving the tailstock shaft, a clamp member for clamping the tailstock body to the bed, and a dog. A tailstock for a machine tool, comprising: a switching mechanism having a mating engaging member, switching a clamp member to an unclamping position at a retracted end position of the tailstock, and switching the clamp member to a clamp position as the tailstock advances.