JP2001314972A - Electrical driving unit for welding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrical driving unit for a welding apparatus which makes moment of inertia small to reduce motor workload corresponding to it and restrains mechanical time constant to be small to provide the motor with versatility. A pressure shaft is composed with a combined shaft with ball thread groove and ball spline groove crossed to shorten the total length of the unit including baffle function so that miniaturization is attainable. SOLUTION: A hole 7 receiving part of the pressure shaft 6 is formed in the rotational shaft 5 of the motor 1, a ball nut 9 is secured to the rotational shaft, and a spline nut 12 is mounted to the front wall 11 of the motor. The pressure shaft is made the combined shaft with the ball thread groove 13 and the ball spline groove 14 crossed. The ball thread groove of the pressure shaft is screwed into the inner circumference of the spline nut via balls, the spline groove is also engaged with the balls dislocated in the inner circumference of the spline nut, thereby the electrical driving unit is united as an electrical driving device for a welding apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric driving device for a welding device having a pressure shaft driven by a motor.

[0002]

2. Description of the Related Art Heretofore, a ball screw device provided with a ball screw shaft having a portion driven by a motor and drawn into the motor, wherein one of the ball screw shaft is attached to a rotating shaft of the motor. And a flange formed on a ball nut is fixed to a flange formed at the tip of the rotating shaft.
Lunut protrudes into the member connected to the end face of the motor,
A spline nut is fixed to the member on the same line as the ball nut, a spline shaft is connected to the tip of the ball screw shaft, the ball screw shaft is screwed to the ball nut, and the spline shaft is connected. The ball screw device which is adapted to engage with the spline nut is, for example,
-73349.

[0003]

However, in the case of the above-mentioned conventional ball screw device, since the connection between the rotary shaft and the ball nut is made at the mutually provided flange portions, the joint surface of the ball screw device is not provided. The diameter is large, the moment of inertia is large, the load on the motor is correspondingly increased, and it is difficult to keep the mechanical time constant small. Since a rotating shaft is required, the motor is also a special motor. Furthermore, since the spline shaft is connected to the tip of the ball screw shaft, the ball nut that is screwed with the ball screw shaft and the spline nut that engages with the spline shaft are located at a certain distance from each other. Inevitably, the length of the shaft is increased, and as a result, the size of the ball screw device may be increased.

[0004] The present invention has been made in view of such problems of the prior art, and an object of the present invention is to dispose a ball nut in a rotating shaft,
A spline nut is located adjacent to the ball nut to reduce the moment of inertia, thereby reducing the load on the motor and reducing the mechanical time constant to give the motor general versatility. Provide an electric drive unit for welding equipment that can reduce the overall length of the equipment including the detent function by using a composite shaft in which the pressure shaft is provided by crossing the ball screw groove and the ball spline groove, thereby achieving downsizing. What you want to do.

[0005]

In order to achieve the above object, an electric drive unit for a welding apparatus according to the present invention is provided with a motor shaft, in which a portion of a pressure shaft is provided for receiving a pressure shaft. And a spline nut is attached to the front wall of the motor, and the pressure shaft is a composite shaft provided with a ball screw groove and a ball spline groove crossed. The ball screw groove of the shaft is screwed into the inner periphery of the ball nut via a ball, and the ball spline groove is engaged with the ball located on the inner periphery of the spline nut. In this way, these electric drive devices are unitized.

[0006] The outer periphery of the nut and the inner periphery of the rotating shaft of the motor may be combined by screwing and fitting.

[0007] Further, a processing portion for manually rotating the rotary shaft is formed at the end of the rotary shaft of the motor opposite to the ball nut side.

In addition, a resolver as a position detector of a pressurizing shaft is arranged on a rotating shaft of the motor.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. In the figure, 1 is a server
The servomotor 1 has a stator winding 3 fixed to an outer shell 2, a rotor magnetic pole 4 disposed on the inner periphery thereof, and the rotor magnetic pole 4 fixed. The rotary shaft 5 is partially constituted by a hollow shaft, and has a storage hole 7 in which a part of a pressure shaft 6 described later can be stored.
The rotary shaft 5 is supported by the outer shell 2 of the servomotor 1 by bearings 8,8. Further, a ball nut 9 having substantially the same diameter as the rotary shaft 5 is fixed to the rotary shaft 5 by a fixing means 10 such as a screw joint.

As means for fixing the ball nut 9 to the rotating shaft 5, the screw connecting means 10 may be used at the inner periphery of the rotating shaft 5 and the outer periphery of the ball nut 9, as described above. Can be appropriately selected from known fixing means such as welding.

The ball nut 9 is provided with the servo
The motor 1 is inserted from the front end face of the front wall 11 of the outer shell 2 of the motor 1 toward the inner periphery of the rotary shaft 5 and is housed in the motor 1. A spline nut 12 is fixed to the front end face of the front wall 11 toward the outside of the motor 1, and the spline nut 12 and the ball nut 9 are arranged substantially adjacent to each other. I have.

The pressing shaft 6 has a ball screw groove 13.
And the ball spline groove 14 are formed in a crossed manner, and the pressing shaft 6 constitutes a composite shaft having both the grooves 13 and 14, and the pressing shaft 6 is a rotating shaft of the motor 1. 5 has a portion to be drawn into the storage hole 7, and a tip portion thereof is protrudable from the spline nut 12 and can be extended. The ball screw groove 13 of the pressure shaft 6 is screwed to the inner periphery of the ball nut 9 via a ball, and the ball spline groove 14 is fitted to the spline nut 12.
Is engaged with a ball (not shown) located on the inner periphery of the ball.

The tip of the pressure shaft 6 extends from the spline nut 12 as described above.
In the mold gun 15, an electrode 16 for welding the work under pressure is used.
However, in the case of an X-type gun (not shown), a well-known connecting member (not shown) for connecting to the gun arm, or in a welding jig (not shown), for example, a well-known work mounting table ―
Cables (not shown) and the like are connected.

The motor 1 incorporates the ball nut 9, the spline nut 12, the pressure shaft 6, and the like in advance and is unitized to form an electric drive unit.

In the electric drive unit of the welding apparatus as described above, the pressurizing shaft 6 is most retracted into the servomotor 1 in the state shown in FIG.
6 is open. In order to increase the extension of the pressure shaft 6 from the spline nut 12 to lead the electrode 16 to the pressurized state from this state, for example, a three-phase current is applied to the stator winding 3 of the servomotor 1. When supplied, the rotor magnetic poles 4 are excited, and the rotating shaft 5 is rotated, and the ball fixed to the rotating shaft 5 is rotated.
The lunut 9 rotates. Then, as the ball nut 9 rotates, the ball arranged on the inner periphery of the ball nut 9 moves along the ball screw groove 13 of the pressure shaft 6, and as a result, the pressure shaft 6 Moves forward, and the electrode 16 of the C-type gun 15 is guided to a pressurized state. When the supply of electric current to the motor 1 is reversed, a part of the pressurizing shaft 6 is sequentially drawn into the housing hole 7 of the rotary shaft 5 and the amount of extension from the spline nut 12 is sequentially increased. And the electrode 16 of the C-type gun 15
Is led to the open state.

The rotation of the ball nut 9 causes the pressing shaft 6 to rotate.
When the shaft moves forward and backward, the pressurizing shaft 6 also tries to rotate, but the pressurizing shaft 6 is configured as a composite shaft as described above, and the ball spline groove 14 formed in the pressurizing shaft 6 is formed. Since the ball arranged on the inner periphery of the spline nut 12 fits therein and moves along the groove 14, the pressure shaft 6 is prevented from rotating by the ball spline groove 14 and the spline nut 12. The pressure shaft 6 is composed of a ball nut 9 and a spline nut 12
The ball is always in the jointed state and moves forward and backward smoothly.

In the electric drive unit of the welding device as described above, since the rotating shaft 5 and the ball nut 9 are connected without using the connecting flange, the inertia moment value of the rotating shaft 5 is reduced. Accordingly, the load on the motor 1 is reduced, and the mechanical time constant is reduced. In addition, since the rotating shaft 5 is not specially shaped, an ordinary motor can be used, and the motor can have versatility.

Further, the pressing shaft 6 is a composite shaft provided by crossing the ball screw groove 13 and the ball spline groove 14, and the shaft 6 is provided with the ball nut 9 and the spline nut substantially adjacent to each other. Since the ball bearing 12 is always in a ball-joined state, the overall length of the device including the rotation preventing function can be shortened, and the size of the electric drive device can be reduced.

Further, the ball nut 9 and the spline nut 12 are disposed adjacent to each other inside and outside the motor 1, and the pressure nut 6 and the pressure nut 6 are assembled in advance to form a unit. This is a versatile electric drive device that can be used in the main body of the device.

If the connecting means for connecting the rotating shaft 5 and the ball nut 9 is formed by combining a screw and a fitting between the inner periphery of the rotating shaft 5 and the outer periphery of the ball nut 9, The connection between the two is ensured, and the deflection of the ball nut 9 can be sufficiently prevented.

As shown in the figure, a processing hole or a processing protrusion (not shown) for manually rotating the rotary shaft 5 is provided at the end of the rotary shaft 5 of the motor 1 opposite to the ball nut 9 side. Z)
In the case where the processing portion 17 is formed, a manual handle (not shown) is attached to the processing portion 17 when the drive device breaks down, and the rotation shaft 5 is rotated by the rotation of the handle, so that the processing is performed. The pressure shaft 6 can be moved to a desired standby position.

Further, as shown in FIG. 2, when a resolver 18 as a position detector for the pressurizing shaft 6 is arranged on the rotating shaft 5 of the motor 1, it is particularly necessary to use a portable gun or the like to artificially operate the gun. The position detector can sufficiently withstand the shock even when a considerable shock is given to the gun due to rough handling of the gun during the movement, and the position of the pressure shaft 6 can be sufficiently detected.

In the above embodiment, a server is used as a motor.
Although the description has been made of the motor employing the motor, an appropriate motor such as a stepping motor, an inverter motor, and a reluctance may be employed as the motor.

[0024]

According to the present invention, a part of the pressurizing shaft is formed in the rotary shaft of the motor, and a ball nut is fixed in the rotary shaft. And a spline nut is attached to the front wall of the motor so as to face the outside of the motor, and the pressure shaft is a composite shaft provided with a ball screw groove and a ball spline groove crossed. The ball screw groove of the pressure shaft is screwed into the inner periphery of the ball nut via a ball, and the ball spline groove is engaged with the ball located at the inner periphery of the spline nut. These electric drive units are unitized to reduce the inertia moment value of the rotating shaft, thereby reducing the load on the motor and reducing the mechanical time constant. And the pressurizing shaft is provided by crossing the ball screw groove and the ball spline groove. A versatile it can be made compact by shortening the overall length of the device, including by Mawari stop function to the axis, and made at a low cost and the electric drive unit of quality stable welding device.

In the case where the outer periphery of the nut and the inner periphery of the rotating shaft of the motor are combined by screwing and fitting,
The electric drive unit of the welding device, which can secure the connection between the two and secure the centering and reinforcement of the ball nut and perform a stable operation.

Further, in the case where a processing portion for manually rotating the rotary shaft is formed at the end of the rotary shaft of the motor opposite to the ball nut side, maintenance and repair of the drive unit are easy. It becomes the electric drive unit of the welding device.

In the case where a resolver as a position detector of the pressing shaft is arranged on the rotating shaft of the motor, the position of the pressing shaft can be reliably detected, and the maintenance of the driving device is easier. It becomes the electric drive unit of the welding device.

[Brief description of the drawings]

FIG. 1 shows an electric drive unit of a welding device according to the present invention C
It is an outline longitudinal section of the important section of what was applied to the type gun.

FIG. 2 is a longitudinal sectional view of an electric drive unit of the welding device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 motor 5 rotating shaft 6 pressurizing shaft 7 storage hole ball nut 9 ball nut 12 spline nut 13 ball screw groove 14 ball spline groove 17 processing part for handle 18 resolver

Claims (4)

[Claims] An electric drive device for a welding apparatus having a pressurizing shaft driven by a motor and having a part drawn into the motor, wherein a part of the pressurizing shaft is housed in a rotating shaft of the motor. A hole is formed, a ball nut is fixed to the rotating shaft, a spline nut is attached to the front wall of the motor, and the pressure shaft is provided by crossing a ball screw groove and a ball spline groove. The ball screw groove of the pressure shaft is screwed into the inner periphery of the ball nut via a ball, and the ball spline groove is positioned on the inner periphery of the spline nut. An electric drive unit for a welding device, characterized in that these electric drive devices are unitized so as to be engaged with a ball. 2. The electric drive unit for a welding device according to claim 1, wherein an outer periphery of said nut and an inner periphery of a rotating shaft of said motor are combined by screwing and fitting. 3. A processing part for manually rotating the rotating shaft is formed at an end of the rotating shaft of the motor opposite to the ball nut side. Electric drive unit of welding equipment. 4. An electric drive unit for a welding apparatus according to claim 1, wherein a resolver as a position detector of a pressurizing shaft is arranged on a rotating shaft of said motor. .