JP2007030063A - Press-in device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a press-in device, achieving press-in with small load, inexpensive and small-sized. <P>SOLUTION: This press-in device includes: an exciter unit 3 having a built-in super-magnetostrictive element periodically elastically deformed according to a periodically changing magnetic field to excite a part P to be pressed in; an air cylinder 2 pressing the excited part P through the exciter unit 3 to press the part P in a member R to be pressed in; and a driving circuit 51 for applying the periodically changing magnetic field to the super-magnetostrictive element to elastically deform the super-magnetostrictive element, wherein the driving circuit 51 sets the frequency and/or intensity of the magnetic field change so as to gradually change. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a press-fitting device, and more particularly to a press-fitting device that performs press-fitting using vibration.

In a press-fitting device or the like that press-fits a valve seat into a port opening of a cylinder head of an engine, conventionally, the press-fitting head is operated by a hydraulic cylinder to apply a large load of about 1 to 2 t to the valve seat. . Patent Document 1 describes a method of press-fitting while applying ultrasonic waves.
JP 50-36343 A

  However, the conventional press-fitting device has a problem that the device is enlarged because a large load is required for press-fitting.

  Therefore, the present invention solves such a problem, and an object thereof is to provide an inexpensive and small press-fitting device capable of press-fitting with a small load.

  In order to achieve the above object, in the first invention, a giant magnetostrictive element (32) which vibrates and deforms periodically in response to a periodically changing magnetic field and vibrates a component (P) to be press-fitted, A pressing means (2) for pressing the excited component (P) through the giant magnetostrictive element (32) to press the component (P) into the press-fitted member (R), and a periodically changing magnetic field Is applied to the giant magnetostrictive element (32) to expand and contract the giant magnetostrictive element (32), and the drive means (51) has a frequency of the magnetic field change and / or in the press-fitting process. The intensity is set to change gradually.

  In the first aspect of the invention, since the parts to be press-fitted are vibrated while being vibrated by the giant magnetostrictive element that is expanded and contracted by the action of the magnetic field, the press-fitting can be performed with a small load. Then, at the time of press-fitting, the frequency and / or intensity of the magnetic field change is gradually changed to optimize the vibration frequency and amount of vibration of the component by the giant magnetostrictive element, so that the press-fitting is performed more smoothly.

  In the second invention, detection means (34, 52) for detecting a change in the magnetic permeability of the giant magnetostrictive element (32) according to the press-fitting load and generating a detection signal corresponding thereto is further provided.

  In the second aspect of the present invention, the permeability of the giant magnetostrictive element changes according to the load applied to it (ie, press-fit load). Therefore, the change of the press-fit load can be detected easily and inexpensively by the detecting means without using a load cell or the like for detecting the press-fit load. Then, it is possible to determine whether or not press-fitting is possible based on the detected change in the press-fitting load.

  In the third invention, for the plurality of parts (P), storage means for storing the change process of the frequency and / or strength of the magnetic field change when the parts (P) are press-fitted, and the press-fitted each According to the component (P), there is further provided selection means for selecting one of the stored change processes and causing the drive means (51) to execute it.

  In the third aspect of the invention, even if the parts to be press-fitted are changed, the optimum press-fitting conditions are immediately selected and smooth press-fitting is performed.

  In addition, the code | symbol in the said parenthesis shows the correspondence with the specific means as described in embodiment mentioned later.

  As described above, according to the present invention, press-fitting can be performed with a small load, and the press-fitting device can be made inexpensive and small.

  FIG. 1 shows the configuration of the press-fitting device. In FIG. 1, a press-fitting device 1 is provided supported by a gantry ST. The press-fitting device 1 includes an air cylinder 2, a vibration body 3 fixed to the lower surface of the air cylinder 2, and the vibration body 3. And a press-fitting head 4 which is fixed to the lower surface and moved up and down by the air cylinder 2.

  FIG. 2 shows details of the vibrator 3. The vibrator 3 is provided with a rod-like giant magnetostrictive element 32 at the center of a housing 31, and a detection coil 33 and a drive coil 34 are wound around the periphery of the element. The driving coil 34 is connected to the driving circuit 51, and the driving circuit 51 supplies driving AC power to the driving coil 34. The drive circuit 51 is a constant current source (effective value), and the frequency and amplitude of the supply current to the drive coil 34 can be changed as described later in the press-fitting process. The detection coil 33 is connected to a detection circuit 52 constituted by a computer or the like. The detection circuit 52 is a constant voltage source (effective value), for example, a voltage of 200 V is applied from the detection circuit 52 to the detection coil 33 at a frequency of 100 Hz, and the applied load to the giant magnetostrictive element 32 is changed as shown in FIG. In response to this, the current of the detection coil 33 changes substantially linearly. By detecting this current value, it is possible to accurately know the load applied from the air cylinder 31 to the giant magnetostrictive element 32 (ie, press-fit load).

  In FIG. 2, a permanent magnet 35 that generates a bias magnetic field for expanding the linear deformation range of the giant magnetostrictive element 32 is disposed around the drive coil 34. The base end of the push rod 35 abuts on the lower surface of the giant magnetostrictive element 32, and the tip of the push rod 35 protrudes out of the housing 31, and the press-fitting head 4 (FIG. 1) is coupled thereto. A disc spring 37 is provided between the push rod 36 and the inner wall of the housing 31 to apply a preload to the giant magnetostrictive element 32.

  Table 1 shows an example of how the amplitude (μm) of the giant magnetostrictive element 32 varies depending on the current value (A) and the frequency (Hz) supplied from the drive circuit 51 to the drive coil 34. According to this, as the frequency increases, the amplitude decreases as a whole, and as the current value increases, the amplitude increases as a whole. The numbers in parentheses are limit currents due to the power supply capacity of the drive circuit 51, and the actual output current is suppressed to this limit current.

  When the component P (FIG. 1) is press-fitted into the press-fitted member R with such a press-fitting device, the air cylinder 2 is extended downward, the tip of the press-fitting head 4 is applied to the component P, and the press-fitting load in this state After the load reaches a predetermined value, the drive coil 34 is energized to generate a periodic alternating magnetic field. The giant magnetostrictive element 32 is periodically expanded and contracted by an alternating magnetic field to oscillate the press-fitting head 4, and the press-fitting process proceeds in this state. The detection circuit 52 detects the press-fit load from the current of the detection coil 34, and determines each process of press-fitting based on the change.

  That is, FIG. 4 shows an example of a load change in a normal press-fitting process, and points a, b, c, and d in FIG. 4 are points where the press-fitting head 4 is in contact with the component P, respectively, and the giant magnetostrictive element 32. This is the point where the vibration is started, the point where the press-fitting is started, and the point where the press-fitting is finished. According to this, the press-fit load gradually decreases from the start of press-fitting (point c), and when the press-fit is completed (point d), the press-fit load increases rapidly due to so-called bottoming. It is possible to detect whether or not the press-fitting is normal and the start / completion of the press-fitting from the change of the press-fitting load.

  FIG. 5 shows an example of a load (BF) that restricts the vibration of the giant magnetostrictive element 32 at each frequency. According to this, in order to ensure the vibration of the giant magnetostrictive element 32 up to about 800 Hz, the press-fit load by the air cylinder 2 needs to be up to about 200 kgf.

  Table 2 shows the experimental results when the ring body is press-fitted into the circular opening. If the press-fitting allowance is 30 μm and the press-fitting load by the air cylinder is 200 kgf, the press-fitting can be completed without vibrating the giant magnetostrictive element. Here, when the press-fitting load is reduced to 100 kgf and the giant magnetostrictive element is vibrated at a drive current of 1 A and 450 Hz, the press-fitting proceeds only about 3 mm out of the 15 mm press-fitting stroke. On the other hand, even if the press-fitting load is 100 kgf, if the frequency of the driving current of the giant magnetostrictive element is gradually changed between 450 Hz and 600 Hz, the press-fitting progresses greatly especially in the vicinity of 500 Hz and the press-fitting of the full stroke is completed. .

  Even when the press-fitting allowance is 70 μm and the press-fitting load is 200 kgf and the giant magnetostrictive element is vibrated at a drive current of 1 A and 450 Hz, the press-fitting proceeds only about 3 mm out of the 15 mm press-fitting stroke. On the other hand, when the frequency of the drive current of the giant magnetostrictive element is gradually changed between 450 Hz and 800 Hz with the same press-fitting load, the press-fitting proceeds greatly especially in the vicinity of 500 Hz, and the press-fitting of the full stroke is completed.

  Even when the press-fitting allowance is 90 μm and the giant magnetostrictive element is vibrated at a drive current of 1 A and 550 Hz with a press-fitting load of 250 kgf, the press-fitting proceeds only about 6 mm out of the 15 mm press-fitting stroke. On the other hand, when the frequency of the drive current of the giant magnetostrictive element is gradually changed between 450 Hz and 700 Hz with the same press-fitting load, the press-fitting greatly progresses especially in the vicinity of 550 Hz, and the press-fitting of the full stroke is completed.

It is a figure showing the whole press-fitting device composition in one embodiment of the present invention. It is a longitudinal cross-sectional view of a vibration body. It is a graph which shows the relationship between a press-fit load and a coil current for detection. It is a graph which shows the change of the press-fit load in a press-fit process. It is a graph which shows the relationship between the frequency of a drive current, and BF.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Press-fit device, 2 ... Air cylinder (pressing means), 3 ... Excitation body, 32 ... Giant magnetostrictive element, 33 ... Detection coil (detection means), 34 ... Drive coil (drive means), 4 ... Press-fit head , 51... Drive circuit (drive means), 52... Detection circuit (detection means), P.

Claims (3)

A super-magnetostrictive element that periodically expands and contracts in response to a periodically changing magnetic field, and vibrates a part to be press-fitted, and the vibrated part is pressed through the super-magnetostrictive element, and the part Pressing means for press-fitting into the pressed-in member, and driving means for causing the super-magnetostrictive element to expand and deform by applying a periodically changing magnetic field to the super-magnetostrictive element, and the driving means in the press-fitting process, A press-fitting device, which is set so as to gradually change the frequency and / or intensity of the magnetic field change. The press-fitting device according to claim 1, further comprising detection means for detecting a change in magnetic permeability of the giant magnetostrictive element according to a press-fitting load and generating a detection signal according to the change. For the plurality of parts, storage means for storing a change process of the frequency and / or strength of the magnetic field change when each part is press-fitted, and the change process stored according to each press-fitted part. The press-fitting device according to claim 1, further comprising selection means for selecting one and causing the driving means to execute the selection.

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