EP-4737037-A1 - TURRET CONTROL DEVICE AND TURRET LATHE

Abstract

To improve the accuracy of a stopping position after rotation of a turret, a turret lathe (100) includes a drive portion (25) configured to rotate, about an axis (C2), a turret (22) that includes twelve turret surfaces (23) to which tool holders (T) including tools (t) are attached; a control portion (34) configured to control an operation of the drive portion (25); a receiving portion (31) configured to receive input of information regarding a tool layout identifying an arrangement in which the tool holders (T) are attached to the turret surfaces (23); a center-of-gravity calculation portion (32) configured to calculate a center of gravity (M') of the turret (22) in the tool layout based on the inputted information regarding the tool layout, information regarding a weight and a center of gravity of the attached tool holders (T), and information regarding a weight and a center of gravity of the turret (22) alone; and an eccentricity calculation portion (33) configured to calculate an eccentricity (δ) of the center of gravity (M') with respect to the axis (C2). The control portion (34) controls a rotation speed of the turret (22) based on the eccentricity (δ).

Inventors

• TAGUCHI NORIYOSHI

Assignees

• Citizen Machinery Co., Ltd.

Dates

Publication Date

20260506

Application Date

20240606

Claims (4)

1. A turret control device comprising: a drive portion that is configured to rotate a turret about a predetermined rotation center, the turret comprising a plurality of turret surfaces to which a tool holder comprising a tool is attached; a control portion that is configured to control an operation of the drive portion; a receiving portion that is configured to receive an input of information regarding a tool layout identifying an arrangement in which the tool holder is attached to the turret surface; a center-of-gravity calculation portion that is configured to calculate a center of gravity of the turret in the tool layout, based on the information regarding the tool layout inputted to the receiving portion, information regarding a weight and a center of gravity of the tool holder attached to the turret surface, and information regarding a weight and a center of gravity of the turret alone; and an eccentricity calculation portion that is configured to calculate an eccentricity of the center of gravity of the turret calculated by the center-of-gravity calculation portion with respect to a position of the rotation center, wherein the control portion is configured to control a rotation speed of the turret by the drive portion based on the eccentricity.
2. The turret control device according to claim 1, further comprising a notification portion that is configured to display information urging a change of the tool layout, wherein the control portion is configured to control the notification portion to notify the information urging the change of the tool layout when the eccentricity is greater than a preset threshold.
3. The turret control device according to claim 1, further comprising an overshoot-amount detection portion that is configured to detect an overshoot amount when an indexing operation is performed in which the turret is rotated at a predetermined rotation speed and the tool holder is then stopped at an indexing position, wherein the control portion is configured to control the drive portion to reduce the rotation speed when the overshoot amount is greater than a predetermined threshold.
4. A turret lathe comprising: a turret device that comprises a turret, wherein the turret rotates about a predetermined rotation center and comprises a plurality of turret surfaces to which a tool holder comprising a tool is attached; a main spindle that is configured to hold a workpiece machined by the tool attached to the turret; and a control device that is configured to control the main spindle and the turret, wherein the control device comprises the turret control device according to any one of claims 1 to 3.

Description

[Technical Field] The present invention relates to a turret control device and a turret lathe. [Background Art] Machine tools such as automatic lathes that include a turret tool post are known in the art. The turret of the turret tool post is formed in a shape of a prism. The turret includes turret surfaces that form peripheral surfaces of the prism, on which tool holders are respectively attached. Tools such as drills and reamers are mounted on the tool holders. The tool holder is selected according to the type of machining to be performed on the workpiece and is attached to each turret surface. The workpiece undergoes machining steps in sequence by the tool holders respectively attached to different turret surfaces. Thus, as the machining process proceeds, it is necessary to perform an indexing operation by rotating the turret to switch the tool holder. Here, in order to shorten the switching time of the tool holder, a layout is sometimes adopted in which the tool holders used in machining are disposed on turret surfaces adjacent in the rotation direction. Then, in particular, when a small number of tool holders are attached to the turret, the tool holders are disposed to concentrate in a specific angular range of the turret. This may lose a weight balance around the rotation center. Thus, an overshoot may occur in which the turret passes over its intended stopping position during an indexing operation of a particular tool holder. This makes it impossible to accurately control the stopping position. After this overshoot, another overshoot may occur in an operation to return to the correct stopping position, thereby causing a hunting operation. A slight deviation in the stopping position causes a phase shift in the engagement of a curvic coupling during rotation of the turret, causing the stopping position to deviate. A turret rotation speed determination device has been proposed that increases the rotation speed of the turret while ensuring the accuracy of the stopping position (see, for example, Patent Literature 1). [Prior Art Documents] [Patent Literature] [Patent Literature 1] Japanese Patent Application Publication No. 2000-218470 [Summary of Invention] [Problem to be solved] The above-mentioned turret rotation speed determination device described in Patent Literature 1 determines the rotation speed of the turret based on the tool layout, or based on the tool layout together with the weight of the tools. However, it does not disclose the tool layout, and the process for determining the rotation speed of the turret is unclear. The present invention has been made in view of the above-described circumstances. An object of the present invention is to provide a turret control device and a turret lathe that are able to improve accuracy of the stopping position after rotation of the turret. [Solution to Problem] According to a first aspect of the present invention, a turret control device includes a drive portion that is configured to rotate a turret about a predetermined rotation center, the turret including a plurality of turret surfaces to which a tool holder including a tool is attached; a control portion that is configured to control an operation of the drive portion; a receiving portion that is configured to receive input of information regarding a tool layout identifying an arrangement in which the tool holder is attached to the turret surface; a center-of-gravity calculation portion that is configured to calculate a center of gravity of the turret in the tool layout, based on the information regarding the tool layout inputted to the receiving portion, information regarding a weight and a center of gravity of the tool holder attached to the turret surface, and information regarding a weight and a center of gravity of the turret alone; and an eccentricity calculation portion that is configured to calculate an eccentricity of the center of gravity of the turret calculated by the center-of-gravity calculation portion with respect to a position of the rotation center. The control portion is configured to control a rotation speed of the turret by the drive portion based on the eccentricity. According to a second aspect of the present invention, a turret lathe includes a turret device that includes a turret, wherein the turret rotates about a predetermined rotation center and includes a plurality of turret surfaces to which a tool holder including a tool is attached; a main spindle that is configured to hold a workpiece machined by the tool attached to the turret; and a control device that is configured to control the main spindle and the turret. The control device includes the turret control device according to the present invention. [Effects of Invention] The turret control device and the turret lathe according to the present invention can improve the accuracy of the stopping position after the rotation of the turret. [Brief Description of Drawings] [FIG. 1] FIG. 1 is a perspective view schematically sho