JP2519610B2 - Electric press method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention applies a predetermined pressing force for press-fitting pins, bushes, pipes, tubes and the like into predetermined holes using an electric press tool, and for caulking and fastening rivets and the like. The present invention relates to the electric pressing method.

[0002]

2. Description of the Related Art For example, an automatic press machine utilizing compressed air or hydraulic pressure is often used in a press-fitting or caulking process for assembling automobile parts or the like. However, it is difficult to control the position by compressed air or hydraulic drive, and a positioning stopper or the like is required in a process requiring positioning, which makes the handling inconvenient. Also, when working in a clean room, the type of power source is restricted,
As shown in Japanese Patent Publication No. 7, a press device using a motor as a power source is used. However, in order to control the load with high accuracy in any press device, a strain gauge type load cell or the like is mechanically connected between the press jig (press body) and the body to be pressed, and the load applied to it is detected and controlled. It is carried out. Therefore, the load can be accurately controlled.

[0003]

However, in the above-mentioned conventional method, the wear of the mechanical connection portion with the load cell or the like causes
Since the position detection value and the load detection value are different, the detection value must be corrected frequently, and if the wear is large, the connecting portion needs to be replaced.
Further, in the conventional automatic press machine, in order to record the detected position and the load value, it is necessary to provide a special measuring device outside, and there is a drawback that the management of the position and the load becomes inconvenient.

Further, in an electric pressing apparatus using a motor, even if the load applied to the object to be pressed exceeds the upper limit or the lower limit of the ideal load increasing characteristic with respect to time, the pressing process is continued as it is, so that the correct pressing is performed. Even though it was not a process, there was a risk that it would be mistaken for the correct pressing process.

Further, conventionally, since the final pressing position of the pressed body is determined by the moving distance from the origin of the press jig (press tool), the height of the pressed body has a dimensional error in manufacturing, for example. In some cases, it is impossible to press to the correct setting position. Further, it was found that if the press jig could be pressed to the correct set position and the press jig was immediately separated from the pressed object from that position, the pressed object could not reach the correct set position due to the rebound phenomenon.

The present invention eliminates the above-mentioned drawbacks of the prior art, is easy to handle, and has stable positioning accuracy.
It is intended to provide an electric pressing method capable of executing a correct pressing operation by controlling an applied load.

[0007]

An electric pressing method according to the present invention is a method of performing a pressing process on a body to be pressed by a pressing jig.
The upper and lower limits of the applied load at the start and end of load application and
And the position of the above-mentioned press jig at the end of load application is set in advance, and when the press jig reaches the above set position in the pressing process, the press jig is stopped at that position for a predetermined time and the body to be pressed rebounds. To prevent the press
The actual applied load to the body is one of the above upper and lower limits
It is characterized in that the pass / fail of the above-mentioned pressing process is determined based on the detection result of whether or not the value exceeds the limit.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

1 and 2 are explanatory views of an apparatus for carrying out the electric pressing method of the present invention. The apparatus shown in FIGS. 1 and 2 stores an electric press tool A, a column B, a bed C on which a workpiece is placed, and various data during operation of the apparatus,
It is composed of a CRT / MDI unit D for monitoring.

In FIG. 1, 1 is a drive motor (AC brushless motor) included in the electric press tool A, 2 is a position detector such as an encoder, 3 is a brake for preventing the press jig from falling, and 4 is a reduction gear. Reference numeral 5 denotes a load detecting portion having a built-in strain gauge for detecting a load applied to the press jig from the torque applied to the motor rotating shaft, 6 is a joint in the column B, 7 is a bearing, and 8 is rotatably supported by the bearing 7. , A ball screw connected to the motor rotating shaft through the joint 6, 9 is a nut screwed to the ball screw 8, and 10 is fixed to the nut 9 in order to change the vertical movement without rotating the nut 9. 11 guide shafts, 11
Is a guide for slidably supporting the guide shaft 10, 12 is a press plate fixed to the lower part of the guide shaft 10, and 13 is a press jig attached to the press plate 12.

Since the electric press tool A in the apparatus for carrying out the method of the present invention does not use a load cell or the like which has been conventionally used, the durability of the load detecting portion 5 is increased and the maintenance is simplified. However, on the other hand, since the load is not directly detected by the load cell or the like, it is necessary to add a calibration value in consideration of various losses of the power transmission unit to the load detection value.

Therefore, in order to press the object to be pressed within the range of the preset press depth and the ideal applied load increase characteristic, the electric tool is controlled while comparing the position detection value of the press jig and the load detection value. , It is necessary to control the speed so that it falls within the range of the increase characteristic. Load sign advance in the press area as shown in Figure 3 in the present invention for the
Set the upper limit values H ₁ and H ₂ and lower limit values L ₁ and L ₂ of the applied load at the start and end of addition , and store those in the CRT / MDI unit D for those exceeding the range and store them as necessary. And give an alarm.

FIG. 4 is a time chart of the position of the press jig 13. In the present invention, when the press jig 13 is moved to a set position at a predetermined speed and the position detection value reaches the set position, the drive motor 1 Reverse current is supplied to and suddenly stopped. After the stop, the rotation of the ball screw 9 is stopped for a predetermined dwell time (for example, 0.9 seconds) to stop the press jig 13 at that position, and then the press jig 13 is returned to the origin dwell time. The position fluctuation due to the rebound of the pressed body that occurs when is not set is prevented.

FIG. 5 shows a press jig 1 for a body to be pressed.
In the present invention, the contact load with the body to be pressed is set in advance, and the position at which the load detection value reaches the contact load setting value is set as the press start position. Press jig 13 from the start position
Is pressed until it moves a predetermined distance so that an error due to the height variation of the pressed object does not occur.

[0015]

As described above in detail, according to the present invention, it is possible to solve the problems of difficulty in position control, securing the position of the pressed body, and wear due to mechanical connection of the load detecting portion, thus stabilizing the apparatus. Sex and accuracy can be maintained. Also, by monitoring the contact load value in the contact area, monitoring the load increase characteristic in the press area, monitoring whether the load upper and lower limit values have been exceeded at the end of press, and monitoring the position from the press start point. Not only can the optimum press state be maintained, but the position and load data of the press jig in the pressing process can be displayed by the CRT / MDI unit D and the optimum press state can be output to the outside. It can be maintained and managed, and each function can be effectively utilized in the FMS line.

[Brief description of drawings]

FIG. 1 is a front view of an apparatus for carrying out the method of the present invention.

FIG. 2 is a side view of an apparatus for carrying out the method of the invention.

FIG. 3 is a time chart of load values on a pressed body.

FIG. 4 is a time chart of the position of a press jig.

FIG. 5 is a diagram showing a contact load of a press jig on a body to be pressed and a press depth of the body to be pressed.

[Explanation of symbols]

 A Electric Press Tool B Column C Bed D CRT / MDI Unit 1 Drive Motor 2 Position Detector 3 Brake 4 Reduction Gear Part 5 Load Detection Part 6 Joint 7 Bearing 8 Ball Screw 9 Nut 10 Guide Shaft 11 Guide 12 Press Plate 13 Press Repair Ingredient

Claims (2)

(57) [Claims] 1. A press jig for pressing an object to be pressed.
Set upper and lower limit value of the applied load during and end load application start-less process and the position of the load applied at the end of the press jig in advance, above the press jig in the pressing process
When the set position is reached, the press jig is stopped at that position for a predetermined time to prevent the rebound of the pressed body, and the actual applied load on the pressed body is below the upper limit.
An electric pressing method characterized in that whether the pressing process is successful or not is judged based on a detection result indicating whether or not any of the limit values is exceeded . 2. The electric pressing method according to claim 1, wherein the setting position of the pressing jig is determined by the moving distance of the pressing jig from the position where the pressing jig contacts the body to be pressed.