JP2008043997A - Pressure-drive unit for welding gun - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-drive unit for a welding gun which is safe, low in cost, and compact in size as a whole by adopting a rotation shaft of a unique hollow motor to fix a screw shaft fixing member to a rear portion of the rotation shaft and reciprocating the pressurizing shaft by screw shaft rotation, and can be easily mounted to various types of position detectors. <P>SOLUTION: The welding gun has a hollow through-hole 6 formed at the rotating shaft 5 of a motor 1 and a pressurizing shaft 8 which is driven by the motor and has a portion drawn in the hollow through-hole of the motor. A screw shaft fixing member 14 is fixed to the rotating shaft rear portion of the motor, and a hole 9 for receiving a screw shaft 19 is formed at the central part in the axial line direction of the pressurizing shaft. Further, a nut 10 is disposed on the pressurizing shaft end side so as to be non-rotatable. The screw shaft is fixed to the screw shaft fixing member, and a position detector 16 is mounted at the screw shaft fixing member side or screw shaft side. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a welding gun having a pressure shaft that has a hollow through hole formed in a rotating shaft of a motor and has a portion driven by the motor and drawn into the hollow through hole of the motor. Is.

  Conventionally, in a welding gun having a pressure shaft driven by a motor and having a portion that is pulled into the motor, a nut is arranged on the end side of the pressure shaft so that the nut cannot be rotated. The rotary shaft of the rotor is formed as a hollow shaft, and a space is formed in the hollow rotary shaft so that the screw shaft is fixed and the nut to be screwed with the screw of the screw shaft can be stored. There is a pressure drive device for a welding gun with a detector attached. (For example, refer to Patent Document 1).

  A C-type welding gun having a pressurizing shaft having a hollow through hole formed in the rotating shaft of the motor and having a portion driven by the motor and drawn into the hollow through hole of the motor; The nut is fixed to the tapped hole formed on the end surface of the rotating shaft, and the screw shaft provided with the screw to be screwed with the nut is used as the pressing shaft. The pressing shaft is made non-rotatable and is inserted into the hollow through hole. There is a C-type welding gun pressurizing drive device having a retracted portion. (For example, refer to Patent Document 2).

JP 2001-293577 A. JP 2000-94143 A.

  By the way, in the former welding gun pressure drive device of the above-mentioned conventional example, since the pressure shaft on which the nut is arranged is also provided in the hollow rotary shaft of the motor, the drive device is shortened. However, the hollow rotary shaft of the motor is formed with a space for fixing the screw shaft, a portion for mounting the position detector, and a space that can accommodate the nut, and is adapted to various types of controllers. Since it is necessary to provide each motor rotation shaft that can be connected to the rotation shaft of the detector, the rotation shaft of the unique hollow motor cannot be used as it is, and the motor is specially adapted to each detector. It must be processed, and the processing is not easy.

  Further, in the case of the pressure driving device for the latter C-type welding gun of the conventional example, since the pressure shaft is a screw shaft, there is a possibility that welding spatter may adhere to the screw shaft during pressurization. There are problems that a means for protecting the screw shaft is required and that the rotation prevention mechanism for the screw shaft is not easy.

  The present invention has been made in view of such problems of the prior art, and the object of the present invention is to adopt the rotary shaft of a unique hollow motor such as the latter as it is, By fixing the screw shaft fixing member to the rear part of the rotation shaft, the pressure shaft is reciprocated by the rotation of the screw shaft, and various types of position detectors can be easily installed, making it safe and cost-effective as a whole. It is an object of the present invention to provide a pressure driving device for a compact welding gun.

  In order to achieve the above object, a pressurizing drive device for a welding gun according to the present invention includes a hollow through hole formed on a rotating shaft of a motor, and the hollow through hole of the motor driven by the motor. In a welding gun having a pressure shaft having a portion to be pulled in, a screw shaft fixing member is fixed to a rear portion of the rotation shaft of the motor, and the screw shaft is housed in the axial center of the pressure shaft. The nut is disposed on the pressure shaft end side so that the nut cannot be rotated, and the screw shaft is fixed to the screw shaft fixing member and the screw shaft fixing member side or the screw shaft side. A position detector is attached.

  The screw shaft fixing member is integrated with the screw shaft in advance, and the screw shaft fixing member is fixed to the rear portion of the rotation shaft of the motor.

  According to a first aspect of the present invention, there is provided a pressurizing shaft having a hollow through hole formed in the rotating shaft of the motor and having a portion driven by the motor and drawn into the hollow through hole of the motor. In the welding gun provided, a screw shaft fixing member is fixed to a rear portion of the rotation shaft of the motor, and a hole for accommodating the screw shaft is formed at the axial center of the pressure shaft, and the end of the pressure shaft Since the nut is arranged on the side so that the nut cannot be rotated, the screw shaft is fixed to the screw shaft fixing member and the position detector is attached to the screw shaft fixing member side or the screw shaft side. It can be shortened, and by using a screw shaft fixing member, the screw shaft can be fixed in the hollow through hole of the rotating shaft, and the motor can be shared with the nut rotating motor, and the position can be detected. Screw shaft fixing member so that it can correspond to different vessel Other need only select the screw shaft, the pressure application driving unit of compact welding gun as a whole in a safe and less costly.

  According to a second aspect of the present invention, the screw shaft fixing member is integrated with the screw shaft in advance, and the screw shaft fixing member is fixed to the rear portion of the rotating shaft of the motor. In addition to the above effect, the screw shaft and the screw shaft fixing member can be easily aligned in advance, and this integrated unit is fixed to the rear portion of the rotating shaft, so that the screw shaft can be accurately positioned with respect to the rotating shaft. A welding gun pressure drive device that can be easily assembled as well as possible.

  A welding gun having a pressure shaft having a hollow through hole formed in a rotating shaft of a motor and having a portion driven by the motor and drawn into the hollow through hole of the motor. A screw shaft fixing member is fixed to the rear portion of the rotary shaft of the rotor, a hole for housing the screw shaft is formed in the axial center of the pressure shaft, and a nut is disposed on the end side of the pressure shaft. , A welding gun pressure drive device in which the screw shaft is fixed to the screw shaft fixing member and a position detector is attached to the screw shaft fixing member side or the screw shaft side.

An embodiment of the present invention will be described with reference to FIG.
In the figure, reference numeral 1 denotes a servo motor. The servo motor 1 includes a stator winding 3 fixed to an outer shell 2 thereof, a rotor magnetic pole 4 arranged on the inner periphery thereof, and the rotation A rotating shaft 5 is fixed to the child magnetic pole 4, and a hollow through hole 6 is formed in the rotating shaft 5. A plurality of tap holes 7 are formed on the rear end surface of the rotating shaft 5.

  Reference numeral 8 denotes a pressure shaft, and a hole 9 is formed in the central portion of the pressure shaft 8 in the axial direction to accommodate a distal end side of a screw shaft, which will be described later, and a nut is disposed on the rear end side of the pressure shaft 8. 10 is fixedly disposed, and the nut 10 is made non-rotatable by providing the nut 10 with a detent member 11 with respect to the pressure shaft 8, and a tip holder on the front end side of the pressure shaft 8. An electrode 13 is attached via 12.

  Reference numeral 14 denotes a screw shaft fixing member. The screw shaft fixing member 14 is a hollow formed of a large diameter portion 15 for fixing a screw shaft, which will be described later, and a small diameter portion 17 for attaching a position detector 16 such as a resolver to the outer periphery. A flange 18 having a hole that matches the tap hole 7 formed in the rear end surface of the rotary shaft 5 is formed at the boundary between the large diameter portion 15 and the small diameter portion 17.

  Reference numeral 19 denotes a screw shaft. The screw shaft 19 is fixed in the large-diameter portion 15 of the screw shaft fixing member 14 by fixing means 20 using wedges, and a screw 21 screwed on the screw shaft 19 is connected to the nut 10. And are to be screwed together.

  Reference numeral 22 denotes a gun bracket. The gun bracket 22 is fixed to the front surface of the motor 1. A fixed arm 23 is fixed to the gun bracket 22 and the axial center portion thereof A hole 24 through which the pressure shaft 8 is inserted is formed, and a linear motion bearing 25 is fixed to the tip side of the hole 24. Reference numeral 26 denotes a welding transformer placed on the fixed arm 23.

  When the servo motor 1 is driven from the state shown in FIG. 1, the welding gun passes through the screw shaft fixing member 14 fixed in the hollow through hole 6 by the rotation of the rotating shaft 5 of the servo motor 1. As a result, the screw shaft 19 rotates. As the screw shaft 19 rotates, the nut 10 screwed with the screw 21 advances along the screw shaft 19 with the pressure shaft 8, and the electrode 13 approaches the other electrode 27 by the advance of the pressure shaft 8. The welding operation is performed with a work (not shown) sandwiched between the electrodes 13 and 27.

  In the pressurizing drive device for the welding gun as described above, the screw shaft fixing member 14 is used and the screw shaft fixing member 14 is simply fixed to the tap hole 7 formed in the rear end surface of the rotary shaft 5. The nut rotating motor with nuts fixed to the end face of the rotating shaft such as is easily applied to the screw shaft rotating motor as in the present invention without any special processing on the rotating shaft. The driving device can be shortened, and the mounting portion of the screw shaft fixing member 14 is the rear portion of the rotating shaft 5, so that the mounting can be performed accurately and easily. Moreover, even if the position detector 16 is different, the position detector 16 can be easily attached by simply selecting the screw shaft fixing member 14 so as to correspond to the position detector 16, the manufacturing cost of the drive device is easy, and the welding gun is safe and compact as a whole. Pressure drive It made.

  In addition, although screwing using the tap hole 7 as a fixing means of the screw shaft fixing member 14 to the rear part of the rotating shaft 5 of the motor has been described, the fixing means includes an inner peripheral surface of the rear part of the rotating shaft of the motor. It is also possible to employ fixing by wedges between the outer peripheral surface of the large-diameter portion 15 of the screw shaft fixing member 14.

Another embodiment of the present invention will be described with reference to FIG.
In this embodiment, the small-diameter portion 17 of the screw shaft fixing member 14 in the previous embodiment is omitted or a short cylindrical shape, and the rear end portion side of the screw shaft 19 is exposed, and a position detection such as an encoder is provided in the exposed portion Since there is substantially no difference in configuration except that the device 16 is attached, the same reference numerals are given and description thereof is omitted.

  In the welding gun pressurizing drive device in this embodiment, the screw shaft fixing member 14 is used and the screw shaft fixing member 14 is simply fixed to the rear portion of the rotating shaft 5 so that the rotation shaft as in the conventional example is obtained. The nut rotation motor with the nut fixed to the end face can be easily applied to the screw shaft rotation motor as in the present invention without any special processing on the rotation shaft. Since the drive device can be shortened, and the mounting portion of the screw shaft fixing member 14 is the rear portion of the rotating shaft 5, the mounting can be performed accurately and easily, and the position detector 16. The position detector 16 can be easily mounted simply by selecting the screw shaft 19 so as to correspond to the difference, the manufacturing cost of the driving device is easy, and the pressure driving device for the welding gun is safe and compact as a whole. .

A further embodiment of the present invention will be described with reference to FIG.
In this embodiment, the screw shaft fixing member 14 in the previous embodiment is integrated with the screw shaft 19 in advance by, for example, welding, detent locking or the like, and the screw shaft fixing member 14 is integrated with the rotating shaft of the motor 1. Since the configuration is substantially the same except that it is fixed to the rear part, the same reference numerals are given and the description thereof is omitted.
It should be noted that the rear end portion 28 of the screw shaft 19 can be freely formed in diameter so that it can be adapted to various types of position detectors 16.

  In this embodiment, the welding gun pressure drive device uses the screw shaft fixing member 14 to easily fix the screw shaft fixing member 14 to the rear portion of the rotation shaft 5, thereby rotating the rotation shaft as in the conventional example. The nut rotation motor with the nut fixed to the end face can be easily applied to the screw shaft rotation motor as in the present invention without any special processing on the rotation shaft. The drive device can be shortened, and the screw shaft 19 and the screw shaft fixing member 14 can be easily aligned in advance, and the integrated member is fixed to the rear portion of the rotation shaft, so that the screw for the rotation shaft 5 is fixed. Accurate positioning of the shaft 19 can be facilitated and the assembly thereof can be simplified, and the position detector 16 can be simplified simply by selecting the screw shaft 19 to correspond to various types of position detectors 16. Attached , Manufacturing cost of the driving device tends, a pressure application driving unit of compact welding gun as a whole and safe.

It is a principal part longitudinal cross-sectional view of one Example of the pressurization drive device which concerns on this invention. It is a principal part longitudinal cross-sectional view by the side of the rear-end part of a screw shaft in the other Example of the pressurization drive device which concerns on this invention. It is a principal part longitudinal cross-sectional view by the side of the rear-end part of a screw shaft in the further another Example of the pressurization drive device which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor 5 Rotating shaft 6 Hollow through-hole 8 Pressure shaft 9 Hole 10 Nut 14 Screw shaft fixing member 16 Position detector 19 Screw shaft 20 Fixing means

Claims (2)

  A welding gun having a pressure shaft having a hollow through hole formed in a rotating shaft of a motor and having a portion driven by the motor and drawn into the hollow through hole of the motor. A screw shaft fixing member is fixed to the rear portion of the rotary shaft of the rotor, a hole for housing the screw shaft is formed in the axial center of the pressure shaft, and a nut is disposed on the end side of the pressure shaft. And a position detector attached to the screw shaft fixing member side or the screw shaft side, and a pressure drive device for a welding gun, wherein the screw shaft is fixed to the screw shaft fixing member. 2. The welding according to claim 1, wherein the screw shaft fixing member is integrated with a screw shaft in advance, and the screw shaft fixing member is fixed to a rear portion of the rotation shaft of the motor. Gun pressure drive device.