JP2003103375A - Pressurized shaft drive device for electric gun - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressurized shaft drive device for an electric gun by disposing a member constituting the pressurized shaft drive device in a housing constituted of a body whose one side is open and a plate covering the open part so as to assemble simply the pressurized shaft drive device with accuracy, and by making the through hole formed on the front wall of the housing bearingless so as to obtain the electric gun small in the effect of a spatter. SOLUTION: In the pressurized shaft drive device, the cross-sectional shape of the housing 1 is constituted of the approximately U-shaped body 2 and the plate 3 covering the open part, the pressurized shaft drive member constituted of a pressurized shaft 5, with a ball screw mechanism 4 assembled in its rear part, a direct acting rolling bearing 6 fixed to the pressurized shaft, and a rail 7 assembled to the direct acting bearing is disposed in the housing, and the through hole formed on the front wall 15 of the housing is made bearingless.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric gun pressurizing shaft driving device for driving a welding gun connected to a wrist of a robot by a servomotor. It is about. 2. Description of the Related Art Conventionally, a C-type electric gun for driving a welding gun connected to a wrist of a robot by a servomotor has a C-shaped arm fixed to a housing of the electric gun. And
A ball screw mechanism for converting the rotation of the output shaft of the servomotor into reciprocating motion of a movable arm serving as a pressurizing shaft is provided in the housing, and a movable arm for holding the ball screw mechanism is provided. It is known that a direct-acting type rolling guide mechanism is provided between a housing and a housing (for example, see Japanese Patent Application Laid-Open No. Hei 9-47881).
In this known electric gun, a pressurizing shaft for holding a ball screw mechanism is arranged inside a cylinder forming a housing, and a ball forming a linear motion rolling bearing is provided at a rear end of the pressurizing shaft. And a rail having a guide groove on the surface facing the ball box is fixed to the inner wall of the cylinder, and these pressure shaft driving devices are assembled inside the cylinder. [0003] However, in the case of the above-mentioned conventional example, a pressurizing shaft driving device including a rail, a bearing, a ball screw mechanism and the like is mounted in a housing. There are problems that the operation is troublesome, that it is difficult to obtain an accurate product, and that the cost is high. The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a pressing shaft driving device having a main body having one side open and a main body. Placing it in a housing consisting of a plate that covers the open part makes it easy to assemble a high-precision pressure shaft drive, resulting in low cost and a bearing-less through hole formed in the front wall of the housing. Therefore, it is an object of the present invention to provide a pressurizing shaft driving device for an electric gun which can obtain an electric gun which is less affected by sputtering. [0005] In order to achieve the above object, a pressurizing shaft driving apparatus for an electric gun according to the present invention comprises:
A ball screw mechanism for converting the rotation of the output shaft of the motor into a reciprocating motion of the pressure shaft is provided in the housing, and a linear motion rolling guide is provided between the housing and the pressure shaft holding the ball screw mechanism. A pressure shaft having a substantially U-shaped main body having one side open in a cross-sectional shape and a plate covering the open portion, and a ball screw mechanism incorporated in a rear portion; A pressing mechanism member comprising a linear motion rolling bearing fixed to the pressure shaft and a rail combined with the linear motion rolling bearing is disposed in the housing and formed on the front wall of the housing. The through hole is made bearingless. An embodiment of the present invention will be described with reference to FIGS. 1 and 2. In the drawing, reference numeral 1 denotes a housing composed of a main body 2 having a substantially U-shaped cross section and an open side, and a plate 3 covering the open portion. A pressure shaft 5 incorporating the mechanism 4 and a linear motion rolling bearing 6 fixed to the pressure shaft 5
And a rail 7 combined with the linear motion rolling bearing 6.
Is disposed. The ball screw mechanism 4 includes a screw shaft 8 and a ball nut 9 that meshes with the screw shaft 8.
Has a ball nut 9 and a rear end supported by a bearing 10, and a rear end of the pulley 11 through which a driving force is transmitted from a servo motor (not shown) via a belt.
Is fixed. The ball nut 9 has a rectangular flange 9 'formed at the rear portion thereof, and is fixed to the rectangular portion at the rear end of the pressure shaft 5 by a plurality of screws 12, 12... At the flange 9'. The pressing shaft 5 is provided with protrusions 13 for holding screws on the upper and lower sides of the rear end, and the screws 1 inserted through the protrusions 13 are provided.
At 4, 14,..., The pressure shaft 5 and the linear motion rolling bearing 6 are integrated. The pressure shaft 5 extends outside the housing 1 through a through hole 16 formed in a front wall 15 covering the front end of the housing 1, and for example, one gun arm of an X-type electric gun. And pressurizes the electrode attached to the tip of the gun arm. A bearing is not provided in the through hole 16, and the pressure shaft 5 is inserted through the through hole 16 with a gap, and a scraper 17 and a dust seal 18 are fitted in the gap. The through hole 16 is so-called bearingless. When the electric gun is a C-type electric gun, the pressing shaft 5 constitutes a movable arm, and the front wall 15 of the housing 1 constitutes a rear end of a fixed arm. The through holes 16 are formed at the rear end of the fixing arm. The linear motion rolling bearing 6 has a substantially U-shaped cross section, and a rail 7 is disposed on the open side thereof. The upper and lower surfaces of the bearing 6 facing the rail 7 have
V-shaped grooves 20, 20 for accommodating the rails 19, 19 are formed so as to cooperate with V-shaped grooves 21, 21 formed in the rail 7. Reference numerals 22 and 22 are return holes for circulating the ball 19. The rail 7 is mounted on the linear motion rolling bearing 6 and fixed to the plate 3 with screws 23, 23,... To prevent rotation of the pressure shaft 5 and guide the linear reciprocation. Things. Are screws for fixing the plate 3 to the housing body 2. In order to reciprocate the pressurizing shaft 5, which is a movable arm of the C-type electric gun, the pulley 11 is rotated from a servo motor (not shown) via a belt to rotate the screw shaft 8.
Is rotated, and the rotation of the ball nut 9 attempts to rotate. However, the rotational force is suppressed by the linear motion rolling bearing 6 and is converted into forward and backward movement of the ball nut 9.
The pressure shaft 5 incorporating the ball nut 9 at the rear portion moves forward or backward. By the way, a substantially U-shaped main body 2 having a cross section of the housing 1 open on one side and a pre-cover for covering the opening.
A pressurizing shaft 5 incorporating a ball screw mechanism 4 at the rear, a direct-acting rolling bearing 6 fixed to the pressing shaft 5, and a combination of the direct-acting rolling bearing 6. Rail 7
By previously integrating the pressure mechanism member with the plate 3 and fixing the plate 3 to the open portion of the main body 2, a rail that requires particularly precise assembly is provided. Since the rolling bearing 7 and the direct-acting rolling bearing 6 are assembled in advance outside the housing 1, accurate assembly can be easily performed. Further, the screw shaft 8, the ball nut 9, the pressurizing shaft 5, the direct-acting rolling bearing 6, the rail 7 and the like can all be mounted on the plate 3 outside the housing 1 in advance. The attaching operation becomes extremely easy. Further, the front end of the housing 1 is covered with a front wall 15, and a through hole 16 for inserting the pressure shaft 5 is formed in the front wall 15, and the through hole 16 is made bearing-less. Even if spatter adheres to the surface of the shaft 5, no problems such as galling of the bearing occur, and even if the bending shaft is subjected to bending moment by eccentric pressure, the load is applied only by the direct-acting rolling bearing 6. Therefore, the influence on weldability can be minimized. The front wall 15 at the front end of the housing 1 is formed by the rear end of the fixed arm, and a through hole 16 for inserting the pressure shaft 5 is formed at the rear end of the fixed arm. In this case, the entire length of the housing 1 is reduced, and the entire electric gun can be reduced in size. According to the present invention, since the members constituting the pressure shaft driving device are disposed in the housing constituted by the main body having one side open and the plate covering the opening, the precision of the driving is improved. A certain pressure shaft drive is easily assembled, resulting in a C-shaped
Inexpensive electric guns are obtained for both X-types, and the through holes formed in the front wall of the housing are made bearing-less, causing problems such as bearings galling even if spatter adheres to the surface of the pressure shaft. It is a pressure shaft driving device for an electric gun that does not need to be driven.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a main part of a pressing shaft driving device for an electric gun according to the present invention. FIG. 2 is an enlarged cross-sectional view taken along line AA of FIG. [Description of Signs] 1 housing 2 housing body 3 plate 4 ball screw mechanism 5 pressurizing shaft 6 direct-acting rolling bearing 7 rail 15 front wall 16 through hole

Claims (1)

Claims: 1. An electric gun for driving a welding gun connected to a wrist of a robot by a servomotor, wherein an output shaft of the servomotor is rotated by a pressurizing shaft. Bore to convert to reciprocating motion
A linear motion rolling guide mechanism provided between a housing and a pressurizing shaft for holding the ball screw mechanism, the cross section of the housing being substantially U-shaped with one side open. A pressurized shaft composed of a plate-shaped body and a plate covering the open portion, and incorporating a ball screw mechanism at a rear portion; and a direct acting rolling bearing fixed to the pressurized shaft;
A pressurizing mechanism member comprising a rail combined with the linear motion rolling bearing is arranged in a housing, and a through hole formed in a front wall of the housing is made bearingless. Pressure shaft drive.