JPH04289058A - Rotation indexing table for machine tool - Google Patents

Abstract

PURPOSE:To achieve low speed precision indexing and high speed rotation by providing a motor included in a casing of a rotation indexing table, connecting the indexing table directly with it, and performing rotation indexing for a low speed and a high speed by changing a rotation detecting means. CONSTITUTION:A motor 7 is composed of a stator 8 comprising a three-phase winding 8a fixed to a casing 2 and a stator iron core 8b, and a rotor 9 comprising a rotor winding 9a provided at a shaft 6 and a rotor iron core 9b. A rotation detecting means 11 at the shaft 6 detects a change of an excited voltage by a change of mutual positions between a first member 14 fixed to the shaft 6 and a second member 15 when an AC voltage is added to the second member 15 fixed to a casing 2 by an inductosyn, for example, and it is taken as a pulse by an A/D converter. The pulse generated by a rotation number of the first member 14 is changed for pulse generation in two stages or more including 9000 pulses/rotation to 0-400rpm, and 1024 pulses/rotation to 400-6000rpm, for example. An indexing table 3 is fixed to the shaft 6 by a bolt 16, so the rotation of the shaft 6 becomes the rotation of the indexing table 3 as it is.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary indexing table for a machine tool, such as a machining center.

0002

2. Description of the Related Art Conventionally, rotary index tables have been widely used in machine tools. Conventional rotary indexing tables used in machining centers have a maximum rotational speed of about 80 rpm in terms of rotation detection accuracy when using a motor direct drive system, and require a reduction gear including a worm and worm gear and a high-precision indexing detection means. The rotation speed limit is 1 even in combination with
The speed was about 50 rpm. Therefore, a method has generally been used in which the rotation of the motor is transmitted to the indexing table via a reducer including a worm and a worm gear.

[0003] In the conventional rotary indexing table for machine tools,
When performing high-precision indexing, the size increases due to the intervention of a reducer, and the machining space available for machining the workpiece when a rotary indexing table is installed becomes smaller.
The problem is that the indexing rotational speed is low, making it time consuming and inefficient.

0004

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and provides a rotary indexer for machine tools that can be installed in a narrow space and that can perform high-speed rotation in addition to low-speed rotation for high-precision indexing. The challenge is to provide tables.

[0005]

[Means for Solving the Problems] The present invention solves the above problems by providing a motor stator fixed to a casing, a motor rotor provided to a shaft rotatably supported by the casing, and a motor rotor fixed to the shaft. an index table, a rotation detection means for detecting rotation of the shaft, and a control means for controlling the stop of the rotor based on a signal from the rotation detection means; The problem was solved by a rotary indexing table for a machine tool, which is characterized in that the number of generated pulses can be switched in at least two stages.

[0006]

[Operation] According to the present invention, a motor is built into the casing of the rotary indexing table, and the indexing table can be directly connected and driven by the motor. By switching the rotation detection means, the number of pulses per rotation, that is, the rotation speed of the rotor can be increased. By switching the rotation detection means, the rotation speed of the indexing table can be changed between a low speed of 400 rpm and a low speed of 6000 rpm.
It becomes possible to perform rotation indexing at a high speed of around rpm. In other words, low-speed precision indexing and high-speed rotation are possible.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail based on embodiments shown in the drawings.

1 to 4, a rotary indexing table device 1 has a casing 2 and an indexing table 3 rotatably supported by the casing 2. The casing 2 has legs 4 that can be fixed with bolts to a predetermined position such as a table of a machine tool such as a machining center.

A shaft 6 is rotatably supported in the casing 2 by a bearing 5, such as an angular bearing, and a bearing 5', such as a roller bearing.

A motor 7 is built in the casing 2, and the motor 7 has a stator 8 fixed to the casing 2 and a rotor 9 provided on the shaft 6. Although a DC motor, a stepping motor, an induction motor, a synchronous motor, etc. can be used as the motor 7, an induction motor is used because it is easy to manufacture. That is, the stator 8 is formed by a three-phase winding 8a that receives alternating current power from a three-phase power supply and generates a rotating magnetic field, and a stator core 8b.
A rotor 9 is formed by a rotor winding 9a that induces voltage and current and a rotor core 9b.

If the stator 8 and rotor 9 are manufactured in advance based on predetermined motor specifications, the rotary indexing table device can be constructed by fitting and fixing the manufactured stator 8 into the casing 2 and attaching the rotor 9 directly to the shaft 6. Alternatively, it can be easily produced by fitting and fixing it to the shaft 6 via the sleeve 10.

[0012] Unlike a synchronous motor, there is no need to perform operations after assembly using the magnetization of the rotor as a motor, and it is only necessary to assemble the iron core and windings, so the induction motor is easier to assemble than the synchronous motor. Note that synchronous motors have the advantage of being easier to control rotation.

Rotation detection means 11 for detecting rotation of the shaft 6 is provided outside the casing 2. As the rotational position detection means 11, for example, an inductosyn is used. The rotational position detecting means 11 has a first member 14 fixed to a disk 12 fixed to the shaft 6 with a bolt 13, and a second member 15 fixed to the outer surface of the casing 2 with a bolt or the like.

When an alternating current is applied to the second member 15, the first
When the member 14 moves relative to the second member 15, a voltage is induced in the first member 14 due to electromagnetic induction. 1st
Changes in the induced voltage due to changes in the relative positions of the member 14 and the second member 15 are detected and extracted as pulses using an A/D converter.

In this type of rotational position detection means 11, the pulses generated in accordance with the number of rotations of the first member 14 are divided into two or more stages, for example, in the first stage, the first member 1 is rotated from 0 to 400 rpm.
The switching is made such that pulses of 90,000 pulses/rotation are generated for a rotation speed of 4, and pulses of 1,024 pulses/rotation are generated for a rotation speed of the first member 14 of 400 to 6,000 rpm. It is possible. A photoelectric encoder can also be used as the rotational position detection means.

By switching the rotational position detection means 11, 40
Precise angle indexing is possible at rotation speeds up to 0 rpm, and the conventional indexing with a certain degree of precision is 150 rpm.
This is possible up to a rotational speed of approximately 500 m, and the difficulty of high-speed indexing at higher speeds has been solved.

[0017] In this device, the speed is 300rpm or 400rpm.
High-speed, high-precision indexing down to pm is now possible. Moreover, by switching the pulses of the rotational position detection means 11, the motor 7 can rotate at high speeds up to 6,000 rpm, and in addition to its function as a rotation indexing table, it can perform the function of a spindle of a high-speed rotating lathe, as well as the rotation indexing of a machining center. This can now be achieved using a table.

An indexing table 3 is fixed to the shaft 6 by bolts 16, and the rotation of the shaft 6 can be directly caused by the rotation of the indexing table 3. The indexing table 3 is capable of high-speed, high-precision angle indexing and high-speed spindle rotation.

An outer casing 17 is attached and fixed to the casing 2, and a cover 18 is attached to the rear end of the outer casing 17.
is fixed by a bolt 19, and blocks the rotation detection means 11 from the outside.

A plurality of jacket grooves 20 are formed between the casing 2 and the outer casing 17, and a cooling liquid is circulated and supplied to each jacket groove. Provide a suitable sealing member to prevent coolant leakage. The coolant can also be circulated by a pump.

The rotary indexing table device 1 shown in the figure has an induction motor built-in, so assembly is easy and control can be performed electrically. However, when the motor is made to have a high output, There is a problem in that heat is generated due to copper loss, iron loss, etc., and heat is generated due to high speed rotation. However, by forming the jacket groove 20 on the outer peripheral surface of the casing 2, forced cooling becomes possible.
The problem of heat generation can be solved.

A friction disk 21 is fixed to the indexing table 3, and a clamp piston 22 is arranged in the casing 2 so as to sandwich the friction disk 21. By pressing the clamp piston 22 toward the friction disk 21 using hydraulic pressure, The friction disk 21 is clamped into a locked state, and the index table 3 is prevented from rotating and held stopped. When the hydraulic pressure is released, the clamp piston 22 is separated from the friction disk 21 by the force of the spring 23, releasing the clamp.

The clamping device is not limited to the hydraulic example shown in the figure, but can also be replaced with a mechanical locking mechanism.

A front cover 24 fixed to the casing 2 so as to sandwich the clamp piston 22 is arranged to surround the outer periphery of the indexing table 3, and there is a gap between the indexing table 3 and the front cover 24 as shown in the figure. It is sealed by any suitable sealing means 25, including a sealing ring shown in Figure 1, or a labyrinth.

A seal member 26 provides a seal between the rear cover 18 and the shaft 6.

Rotary indexing table device 1 shown in FIGS. 1 to 4
is fixed to a rotary table 32 of a machining center 31, as shown in FIG. 5, and a workpiece fixed to the indexing table 3 can be machined using a tool provided on a main shaft 33.

It is possible to perform angle indexing at high speed and with high precision using a device such as shown in FIG. 5, and recently it is possible to process a blade portion having an involute curve or an approximate involute curve, such as a rotor for a compressor, while indexing at high speed rotation. is now possible. Furthermore, by switching the indexing table to high-speed rotation, it became possible to perform turning work using the machining center.

[0028]

[Effects of the Invention] According to the present invention, the indexing table is rotated by a built-in motor and directly driven by the motor, so high-speed rotation is possible, and high-speed, high-precision indexing is possible using the rotational position detection means. In addition, high-speed rotation became possible, and the function of a lathe spindle could also be achieved by a rotary indexing table.

By using a means that utilizes electromagnetic induction, such as an inductosyn, as the rotational position detection means, the space can be reduced, and the length of the rotary indexing table device in the axial direction can be made very short. This makes it possible to expand the effective machining space of the machining center.

[Brief explanation of the drawing]

FIG. 1 is a front view of a rotary indexing table device according to the present invention.

FIG. 2 is a left side view.

FIG. 3 is a bottom view.

FIG. 4 is a front sectional view.

FIG. 5 is a diagram showing an example of use in a machining center.

[Explanation of symbols]

1 Rotary index table 2 Casing 3 Index table 6 axis 7 Motor 8 Stator 9 Rotor 11 Rotation detection means

Claims (2)

[Claims] 1. A motor stator fixed to a casing, a motor rotor provided on a shaft rotatably supported by the casing, an index table fixed to the shaft, and a rotation of the shaft detected. It has a rotational position detection means and a control means for controlling the stop of the rotor based on a signal from the rotational position detection means, and the number of pulses generated per rotation of the rotational position detection means can be switched to at least two levels. A rotary indexing table for a machine tool, characterized by: 2. The rotary indexing table for a machine tool according to claim 1, wherein the motor constituted by the stator and rotor forms an induction motor.