JP2620149B2 - Inspection method of press fit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION = Object of the Invention = [Industrial Application Field] The present invention relates to a plate, a pipe, a rod, or the like having a relatively small press-fitted object such as a pin, which has a hole provided for press-fitting. The present invention relates to a press-fit state inspection method for judging whether or not the press-fitted article is normally press-fitted when the press-fitted article is press-fitted.

[Conventional technology]

Conventionally, as a method for judging whether or not a press-fitted object is normally press-fitted into a hole provided in a press-fitted object, a press-fitting load at the time of press-fitting is measured by a load measuring device such as a load cell, and press-fitting is completed from the start of press-fitting. Press-fit maximum load indicating its peak value up to 10 hours
A ₁ is desired standard range set in advance (10Amin <10A ₁ <
The appropriateness of the press-fit state was determined based on whether the pressure was within 10Amax).

As shown in FIG. 9, the principle of which is described in a block diagram as an example of a conventional press-fitted state inspection method, the press-fitted state inspection apparatus measures a press-fit load applied to a press-fitted object and determines whether the press-fitted state is appropriate. Is provided. Specifically, a load cell 101 attached to a press-fitting device and measuring a load at the time of press-fitting as a strain amount, an amplifier 103 for amplifying the strain amount in the load cell 101, an A / D converter 105 for converting an analog signal into a digital signal. And a signal processing function such as a comparison device 108 for judging whether the press-in state of the press-in object is normal or abnormal.

[Problems to be solved by the invention]

However, according to the inspection method described above, the maximum load
10A ₁ Despite satisfies the standard range, problems such as when fitting the worst loose press fit of the press-fitting thereof relative to the hole of the press-fit material in or at the time of use during transport of the products from falling May occur.

That is, even when the maximum load 10A ₁ during press-fitting is within the standard range, press-fitting of such pins with respect to the hole portion of the press-fitting thereof,
There is a case where the actual length actually fitted, that is, the so-called press-fitting distance is not appropriate, and the fitting length (press-fitting distance) is not sufficient, which may cause problems such as falling off.

Therefore, according to the conventional method, the method of evaluating the press-fitting state has a problem in terms of quality reliability and reliability.

= Configuration of the Invention = [Means for Solving the Problems] 1. When press-fitting a pin or the like into a hole provided in the press-fitted object, press-fitting to determine whether or not the press-fitted material has been normally press-fitted. In the condition inspection method, the measured values of three variables of the maximum press-fit load and press-fit distance from the start of press-fit to the end of press-fit, and the amount of press-fit energy indicating the energy required for press-fit are within the desired standard range for each variable. It is determined whether or not the press-fit state of the press-fitted article is appropriate based on whether or not there is any.

2. The measured values of the three variables of the maximum press-fit load and press-fit distance from the start of press-fit to the end of press-fit, the amount of press-fit energy indicating the energy required for press-fit, and the results of comparison with the desired specification range of each variable. Is displayed graphically on the screen of the display device 9, and the appropriateness determination of the appropriateness of the press-fit state is displayed on the screen.

(Examples and actions)

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 6 is an explanatory view of a main part of a press-fitting device 15 according to an embodiment of the present invention, in which 20 is a hollow pipe as a press-fitted object, and 22 is a press-fitting hole provided in the hollow pipe 20. Reference numeral 21 denotes a fitting pin as a press-fit.

FIGS. 2 and 3 are enlarged views of a portion M in FIG. 6, and show a press-fitting step of press-fitting the press-fitting material 21 into the hole 22 provided in the press-fitting material 20, and each state before press-fitting is shown in FIG. FIG. 3 shows a state in which the press-fitting is completed.

The press-fitting device 15 for applying a predetermined press-fit load to the press-fitting material 21 and press-fitting the press-fitting material 21 into the hole portion 22 includes a press-fitting terminal 17 that abuts on the press-fitting material 21 and presses the press-fitting material 21. Load cells 1, which are installed in series and measure the press-fit load applied to the press-fit terminal 17,
And a distance sensor 2 for measuring the press-fitting distance.

A strain gauge (not shown) is mounted in the load cell 1, and the press-fitting load A is measured as a strain amount of the strain gauge. Further, the distance sensor 2 is a measuring terminal supported movably in the axial direction by a not-shown ridge.
And the measurement terminal 18 is provided so as to face a mechanism 16 interlocking with the load cell 1, and a change in the relative position in the axial direction of the press-fit terminal 17 provided at the tip of the load cell 1 is controlled by the interlocking mechanism. The signal 16 is transmitted to the measuring terminal 18 of the distance sensor 2 to measure the fitting length between the press-fitted object and the press-fitted object, that is, the press-fit distance B.

FIG. 1 is a view for explaining the principle of a method for inspecting a press-fit state according to an embodiment of the present invention. The press-fitting device 15 is provided with a signal processing function for determining the appropriateness of the press-fit state after measuring the load A and the press-fit distance B at the time of press-fitting, and a function of graphically displaying the press-fit state together with the appropriateness determination.

Specifically, first, a load cell 1 that is attached to the press-fitting device 15 and measures a press-fitting load A and a distance sensor 2 that measures a press-fitting distance B, an amplifier 3 that amplifies an electric signal in the load cell 1 and the distance sensor 2, 4. A / D converters 5 and 6 for converting analog signals to digital signals, and the bivariate A and B
A computer 7 having an arithmetic function for calculating the amount of press-fit energy C according to
The display device 9 displays the press-fit state inspection result.

The computer 7 has an arithmetic function for calculating the press-fit energy amount C from the measured values of the press-fit load A and the press-fit distance B. That is, as shown in FIG.
If the curve showing the change in the press-fitting load B was f (x), the press-fitting amount of energy C is calculated by the formula _{^{W = ∫ d 0 f (x}} ) dx. Further, based on each of the measured values, the three variables of the maximum load A ₁ at the time of press-fitting, the press-fitting distance B ₁ , and the amount of press-fit energy C ₁ are extracted as the three variables for which the press-fitting state is to be evaluated. The computer 7 is provided with a comparison function 8 for judging whether or not the press-in state of the press-in object is appropriate by comparing the desired standard range.

A display device 9 such as a cathode ray tube displays the measurement results of the three variables graphically 13 and displays a judgment 12 as to whether or not the press-fitting state is appropriate, as shown in FIG. 4 and FIG.
Having.

Subsequently, a method of inspecting the press-fit state according to the present invention will be described.

First, the press-fitted object 20 having the hole 22 provided for the purpose of press-fitting is inserted into the press-fitting device 15 as shown in FIG.
The hole 22 is set so as to face the press-fit terminal 17 to press the press-fit 21. Next, after a press-fitting object 21 such as a pin is positioned with respect to the hole 22 as shown in FIG.
When a predetermined load is applied in the axial direction by 15, the press-fitting object 21 is pressed into the hole 22 by the pressing of the press-fitting terminal 17. As shown in FIG. 3, the press-fitted state is shown.
21 is a hole 22 compared to the press-fitting start state indicated by the two-dot chain line.
It is press-fitted by a distance represented by the fitting length B ₁ to.

As described above, as a method of inspecting the press-fit state when the press-fit 21 is pressed into the press-fit 20 having the hole 22, as shown in FIG. The press-fit load A applied to the press-fit 17 by the load cell 1 is measured, and the fitting length in the axial direction of the press-fit 21 and the hole 22 by the distance sensor 2 similarly attached to the press-fitting device 15, that is, The press-fit distance B is measured.

Next, the electric signals indicating the press-fit load A and the press-fit distance B obtained by the load cell 1 and the distance sensor 2 are converted into digital signals by passing through the amplifiers 3, 4 and the A / D converters 5, 6, respectively. The data is converted and supplied to the computer 7.

In the computer 7, the press-fit energy amount C is calculated from the measured values of the press-fit load A and the press-fit distance B by the calculation function. By comparison function 8 set by the program or the like in the same manner as in the computer 7, 3 variables to be examined the pressed-in condition, i.e. the maximum load A ₁ and press-fit the distance B ₁ to press-fit end than at the press-fitting start, pressed for total energy C ₁ required for the specified range of the desired each variable are compared. At this time, it is compared whether each measured value A ₁ , B ₁ , C ₁ is within the range indicated by the minimum value / maximum value of each standard range, and the measured values A ₁ , B _{1 of the} three variables are compared. only if the C ₁ is in all standard range as shown in the following, the press-fitting condition is determined to be "relevant".

FIGS. 7 (a), (b), and (c) show the results of measurement of the relationship between the punching load of the press-fitted object to the press-fitted object and the three variables related to the press-fitting. In particular, a strong positive correlation is shown in the relationship between the amount of press-fit energy and the unloading load in (b), and the press-fit state is inspected with each of the three variables compared to the conventional method of inspecting only with the maximum press-fit load. It is clear that the press-fit state can be grasped more appropriately.

The data transmitted through the computer 7 is sent to the display device 9, and as shown in FIG. 4 and FIG. Is displayed.

The graphic display 13 is represented by, for example, a radar chart-like graphic centered on each variable, and the press-fit state is visually grasped by the display graphic 13.

As an example of the display method, FIG. 4 shows that the press-fit state is shown as “OK” (suitable) because each measured value is within each standard value range, and FIG. 5 shows the press-fit distance B _1. Is less than the minimum standard value Bmin, the press-fit state is “NG” (inappropriate), and the appropriateness determination display 12 is performed.

Therefore, according to the present invention, not only the maximum load at the time of press-fitting but also the press-fitting state is inspected by the three variables of the press-fitting distance and the amount of energy required for the press-fitting. The condition can be evaluated quantitatively. Further, since the press-fit state is immediately displayed as a graphic on the screen, the press-fit state can be qualitatively evaluated.

= Effect of the Invention = As described above, according to the present invention, not only the maximum load at the time of press-fitting but also the press-fitting state is inspected by the three variables of the press-fitting distance and the amount of energy required for the press-fitting, so that the press-fitting state can be surely grasped. The press-fit state can be quantitatively evaluated while improving the properties. Further, since the press-fit state is immediately displayed as a graphic on the screen, the press-fit state can be qualitatively evaluated as a pattern. Therefore, it is possible to improve the reliability in the inspection of the press-fit state and to provide an inspection method excellent in man-machine interface.

[Brief description of the drawings]

1 to 8 show an embodiment of the present invention.
Figures are explanatory diagrams of the principle of the press-fitting state inspection method, FIGS. 2 and 3 are partial cross-sectional plan views showing the press-fitting process, and FIGS. 4 and 5 show the press-fit result displayed on the screen of the display device. FIG. 6 is an explanatory view showing the main part of the press-fitting device, FIG. 7 is a graph showing the relationship between each variable and the punching load, and FIG. 8 is a graph showing the relationship between the press-fitting distance and the press-fitting load. FIG. 9 is an explanatory view of the principle of a conventional press-fit state inspection method. (Explanation of symbols) 1. Load cell. 2. Distance sensor. 7 Computer. 8. Comparison function. 9 Display device. 11 ... Screen. 12 ... Decision judgment. 20 …… Press-fit. 21 ... Injection. 22 ... hole. A: Press-fit load. B: Press-fit distance. C: Injection energy. A ₁ …… Measured maximum press-fit load. B ₁ …… Measured value of press-fit distance. C ₁ …… Measured value of injection energy.

Claims (2)

(57) [Claims] 1. A press-fitting state inspection method for judging whether or not a press-fitted object is normally press-fitted when a press-fitted object such as a pin is pressed into a hole provided in the press-fitted object. Whether the measured values of the three variables of the press-fit maximum load A ₁ and press-fit distance B ₁ until the end and the press-fit energy amount C ₁ indicating the energy required for press-fit are within the desired standard range of each variable. A press-fit state inspection method for determining whether the press-fit state of the press-fit 21 is appropriate. 2. A measured value A ₁ , B ₁ , of three variables of a press-fit maximum load A ₁ and a press-fit distance B ₁ from the start of press-fit to the end of press-fit, and a press-fit energy amount C ₁ indicating energy required for press-fit. C ₁ and
A result of comparing each variable with a desired standard range is graphically displayed 13 on a screen 11 of the display device 9, and an adequacy determination 12 for determining whether the press-fit state is appropriate is displayed on the screen 11. 2. The method for inspecting a press-fit state according to claim 1.