JPS614632A - Measuring method of forced fit condition in steering shaft - Google Patents

Abstract

PURPOSE:To accurately detect an improper forced fit condition, by the method measuring a forced fit condition on the basis of an actual pressure load applied to parts and an original pressure in the side of a pressure load source, in the case of the method measuring a condition that a steering shaft is forced to be fitted by pressure. CONSTITUTION:The method, for measuring a forced fit condition between two parts in a steering shaft in the steering device of an automobile or the like, is performed in such a manner that beams B1, B2 of two sets of photoelectric switches 11A, 11B consisting of a light emitting device 11a and a light receiving device 11b are left as emitted parallelly to each other slightly above the upper end surface of a yoke 2 positioned on a jig 9. And if a bottom end surface 3a in the large contour part of a shaft 3 is placed approaching the upper end surface of the yoke 2 and intercepting the both beams B1, B2, the shaft 3 being forced to be sufficiently fitted by pressure can be decided. While a forced fit distance being insufficient is decided when the both beams are not intercepted. In this way, an improer forced fit condition can be accurately detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for measuring the press-fit state of two parts in a steering shaft that transmits the rotation of a steering wheel to wheels in a steering device for an automobile or the like.

[Prior art and its problems]

Conventionally, as shown in FIG. 1, for example, when press-fitting a predetermined shaft 3 into the yoke 2 of the universal joint 1 of the steering shaft S and fixing both, the yoke 2 is positioned on a predetermined jig. While firmly fixing the shaft 3, the shaft 3 is press-fitted by applying a large load using, for example, hydraulic pressure as a pressure source using a press-fitting punch (not shown).

Monitoring of the press-fitting state, that is, determining whether the press-fitting amount t of the end of the shaft 3 into the yoke 2 is correct or not, and whether the fitting tolerance is correct or not based on the tightness of the two, is carried out using the press-fitting punch described above. A pressure switch is built into the hydraulic circuit of the
The F signal is used to determine whether the press-fit state is correct or not.

In this type of method, the press-fit state is uniquely determined based only on the so-called original pressure on the hydraulic source side, so it is not foolish to know the actual measured value, and the reliability of the determination result is low. There is a problem.

[Object of the Invention] One object of the present invention is to provide a press-fit condition measuring method that can obtain highly accurate and reliable judgment results based on the method of monitoring the press-fit condition by the press-fit load. shall be.

[Structure of the invention]

In the present invention, the actual press-fitting load at the initial stage of press-fitting is detected when the shaft, which is the second part, is just beginning to be press-fitted into the yoke, which is the first part, and this detected value is compared with a predetermined reference value. a step of determining whether it is correct or not, and detecting the original pressure load on the press-fitting load source side when the shaft, which is the second component, is press-fitted to the yoke, which is the first component, to a predetermined press-fitting amount;
The method includes a step of comparing this detected value with a predetermined reference value to determine whether the detected value is correct or not.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a diagram schematically showing a press-fitting device to which the present invention is applied.
4 is a pace, 5 is a hydraulic cylinder mounted on the base 4 via a post 6 and a mounting plate 7, and a press-fitting punch 8 is attached to the tip of a piston rod 5a of the hydraulic cylinder 5.

In addition, 9 is a jig provided on the base 4, and the jig 9 is
A load cell 10 is provided below.

Then, the yoke 2, which is the first component described above, is positioned on the jig 9, and the shaft 3, which is the second component, supported by a guide member (not shown) is set on top of the yoke 2 in a vertical state. This completes the preparation.

Next, the hydraulic cylinder 5 is extended, and the press-fitting punch 8 is lowered by a predetermined amount. That is, the press-fitting punch 8 contacts and presses the upper end of the shaft 3, and when the lower end of the shaft 3 is press-fitted into the yoke 2 by α (about several millimeters) as shown in FIG. The initial pressure Fl at the initial stage of press-fitting is detected from the output. Then, this initial pressure value R
is temporarily held, and it is compared and determined whether the initial pressure value F1 is within a predetermined allowable range (reference value).

Here, the detection timing of the initial pressure value Fl can be obtained by detecting the downward stroke of the press-fitting punch 8 using a strong limit switch.

Next, as shown in FIG. 4, when the press-fitting of the shaft 3 into the yoke 2 is completed, the hydraulic source pressure F2 on the hydraulic cylinder 5 side is detected, and the source pressure value F2 is set to a predetermined allowable value as a reference value. Compare and judge whether it falls within the range.

Then, a comprehensive judgment is made from the above two judgment results.

If at least one of the above two determination results is "fail", it is determined that the press-fit condition is poor, and if both determination results are "positive", it is determined that the press-fit condition is good. It is determined that In this case, the above-mentioned "poor press-fit condition" means that the interference of the fit between the yoke 2 and the shaft 3 based on the interference fit is not appropriate.

Here, prior to detecting the above-mentioned oil pressure source pressure F2, whether or not the shaft 3 is completely press-fitted into the yoke 2 is detected, for example, as follows.

That is, as shown in FIGS. 5 and 6, two sets of photoelectric switches IIA consisting of a light emitter 11a and a light receiver 11b are placed slightly above the upper end surface of the yoke 2 positioned on the jig 9. This is done by keeping the beams B1 and B of IIB running parallel to each other.

If the lower end surface 3a of the large diameter portion of the shaft 8 approaches the upper end surface of the yoke 2 and blocks both beams B, B2, it can be determined that the shaft 3 has been sufficiently press-fitted. On the other hand, if both beams Bl+B1 cannot be traced, it is determined that the amount of press-fitting is insufficient, and if only one beam B1 or B1 is blocked, the shaft 8 is press-fitted diagonally into the yoke 2. It is determined that the press-fit condition is poor.

〔Effect of the invention〕

[Blank below] As explained in detail above, according to the present invention, the press-fit condition is measured based on the actual press-fit load applied to the part and the original pressure on the press-fit load source side, so that machining errors are avoided. It is possible to accurately detect poor press-fit conditions due to assembly errors and assembly errors, and highly reliable measurement results can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an explanatory view showing the state of press fitting between the yoke and the shaft of the universal joint, FIG. 2 is a schematic explanatory view of a press fitting device to which the method of the present invention is applied, and FIG. 3 is an explanatory view. 4 and 5 are explanatory diagrams for explaining one embodiment of the method of the present invention, and FIG. 6 is a sectional view taken along the line ■-■ in FIG. 5. 2... Yoke (first part), 3... Shaft (second part)
parts), 5... Φ hydraulic cylinder, 10... load cell, S... steering shaft. 2 others

Claims (1)

[Claims] (1) Among the parts constituting the steering shaft, a method in which a predetermined press-fitting load is applied to the second part to measure the press-fitting state of both parts when the second part is press-fitted into the first part, A process of detecting the actual press-fitting load at the initial stage of press-fitting when the second part begins to be press-fitted into the first part, and comparing this detected value with a predetermined reference value to determine whether it is correct or not; On the other hand, there is a step of detecting the original pressure load on the press-fitting load source side when the second part is press-fitted to a predetermined press-fitting limit, and comparing this detected value with a predetermined reference value to determine whether it is correct or not. A method for measuring a press-fitting state of a steering shaft, the method comprising: