JP3522663B2 - Pressurized shaft drive for electric gun - Google Patents

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 constituting a housing, and a linear motion rolling bearing is formed at the rear end of the pressurizing shaft. And a rail provided with 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. ing. [0004] However, in the case of the above-mentioned conventional example, since a pressure shaft driving device including a rail, a bearing, a ball screw mechanism and the like is assembled in a cylindrical housing, The assembling work is troublesome, and it is difficult to obtain an accurate product, the cost is high, and the repair of the gun is not easy. 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 having one side open. A pressurizing shaft drive unit for an electric gun that can be easily assembled with a high-precision pressurizing shaft drive unit by mounting it in a housing composed of a plate that covers the open part, resulting in an inexpensive electric gun. It is intended to provide. [0006] In order to achieve the above object, a pressing 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 direct-acting rolling guide mechanism is provided between the pressure shaft and the housing; An arm on one side is attached to the housing side, and the cross-sectional shape of the housing is composed of a substantially U-shaped main body with one side open and a plate covering the open part, and a ball screw mechanism is incorporated in the rear part. A pressurizing mechanism member comprising a pressurizing shaft, a linear motion rolling bearing fixed to the pressure shaft, and a rail combined with the linear motion rolling bearing is mounted in the housing. The front wall covering the front end
A through-hole for insertion is formed, and the through-hole is made bearingless . An embodiment of the present invention will be described with reference to FIGS. 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 comprises a screw shaft 8 and a ball nut 9 which 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 pressure 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 is formed to have 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 assembled to 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, and the screw shaft 8 is rotated.
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. The housing 1 has a substantially U-shaped main body 2 having a cross-sectional shape opened on one side, and a pre-plate for covering the opening.
A pressurizing shaft 5 having a ball screw mechanism 4 incorporated in the rear part, a linear rolling bearing 6 fixed to the pressing shaft 5, and a linear rolling bearing 6 Rail 7
Since the pressurizing mechanism member is mounted in the housing 1, the rail 7 and the linear motion rolling bearing 6, which require particularly precise assembly, can be assembled outside the housing 1. It is easy to assemble.
The screw shaft 8, the ball nut 9, the pressure shaft 5, the direct-acting rolling bearing 6, the rail 7, and the like can all be attached to the plate 3 outside the housing 1, so that they are assembled. The work becomes extremely easy. [0015] Further, both the cover front end of the housing 1 in the front wall 15, a through hole 16 for insertion of the pressure application shaft 5 is formed in the front wall 15, and the vent hole 16 to the Bearingless Therefore, even if spatter adheres to the surface of the pressure shaft 5, there is no problem such as the bearing galling, and even if the bending moment is applied to the pressure shaft 5 by eccentric pressure, the linear motion rolling bearing Since only 6 receives a load, 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 shortened, and the entire electric gun can be stored compactly. According to the present invention, the cross-sectional shape of the housing is constituted by a substantially U-shaped main body having one side open and a plate covering the open part, and a ball screw mechanism is incorporated in the rear part. The pressurizing mechanism member consisting of a pressurizing shaft, a linear motion rolling bearing fixed to the pressure shaft, and a rail combined with the linear motion rolling bearing is mounted on the housing. A certain pressure shaft drive can be easily assembled, resulting in C
A pressure shaft driving device for an electric gun that can obtain an inexpensive electric gun for both the X-type and the X-type. [0019] Then, both the cover front end of the housing front wall, to form a through hole for insertion of the pressure application shaft to front wall, since the vent holes in the bearingless, the surface of the pressure application shaft Even if spatter adheres, no problems such as bearing galling occur, and even if a bending moment is applied to the pressing shaft by eccentric pressure, the load is applied only to the direct-acting rolling bearing. The effect can be minimized.

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

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B23K 11/11 520 B23K 11/11 550

Claims (1)

(57) [Claim 1] An electric gun for driving a welding gun connected to a wrist of a robot by a servomotor, wherein rotation of an output shaft of the servomotor is applied. Bore to convert to reciprocating motion of pressure shaft
A screw mechanism is provided in the housing, and a direct-acting rolling guide mechanism is provided between the pressure shaft and the housing. An arm on one side is attached to the housing side, and one side of the cross-sectional shape of the housing is opened. A pressurizing shaft comprising a substantially U-shaped main body and a plate covering the open portion, and incorporating a ball screw mechanism at the rear, a linear motion rolling bearing fixed to the pressurizing shaft, A pressure mechanism member comprising a rail combined with the linear motion rolling bearing is mounted in the housing, and the pressure shaft is mounted on a front wall covering a front end of the housing.
A pressure shaft driving device for an electric gun , wherein a through hole for insertion is formed, and the through hole is made bearingless .