JPS61136013A - Locking structure of washer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a structure that prevents washers from rotating together due to the rotation of bolts and nuts when they are tightened.

[Conventional technology]

As a conventional washer, there is one shown in FIG. 9, for example. This figure shows the state of tightening of bolts used for tightening engine cylinder hemlocks, bolts used for crankshaft hair ring attachment caps, etc.

In the figure, pol) (11 is inserted into the washer (2),
It further penetrates the object to be tightened (3), is screwed into the female threaded member (4), and is then tightened by applying a predetermined tightening torque.

The role of the washer (2) in this case is to prevent the bearing surface (6) of the object to be tightened from being damaged by the rotation of the bolt and to stabilize the coefficient of friction.

In other words, without this washer, the bolt seating surface (5) would come into direct contact with the seating surface (6) of the object to be tightened, and the object to be tightened is generally aluminum alloy or cast iron. It is softer than bolts that have increased strength so that it will not break even when subjected to tightening force, and the object to be tightened is more likely to be damaged by the rotation when tightening the bolt, and the shaft surface of the bolt is more likely to be rounded. In some cases, the head becomes eccentric due to rotation, so the contact with the object to be tightened changes, and the object to be tightened is likely to be scraped and shavings are generated, and these swarfs can get inside the engine. This will circulate together with the engine oil, causing seizure of various sliding parts. In addition, it is difficult to guarantee the surface roughness, flatness, and parallelism of the seat surface of the clamped object if the surface is left as cast, so counterbore holes are applied by milling etc. The finished surface roughness and flatness change depending on the state of wear of the cutting edge, and when tightening a bolt, the relationship between the tightening axial force and the tightening torque (friction coefficient on the bearing surface) varies greatly. .

Therefore, the above-mentioned problems are solved by controlling the surface roughness and flatness by pressing, etc., and using a washer that has been tempered to have high hardness.

As shown in Fig. 9, from the surface pressure distribution p on the bearing surface, the friction circle radius r is larger on the bearing surface side of the object (q). If the coefficient of friction between the surfaces is the same, the vertical surface will naturally be the same as the seat surface (5
), but for the reason mentioned earlier, the coefficient of friction of the seat surface of the clamped object changes, so a slip surface may occur on the clamped part side. As shown in Figure 4, the relationship between tightening torque and tightening axial force is as follows:
It varies widely. In the figure, the broken line indicates that when the tightening torque is low, the sliding surface is the bolt seating surface, but it changes to the tightened object seating surface midway through, resulting in subtle changes in the coefficient of friction and the coefficient of static friction. Such a clear tendency appears due to the difference in the coefficient of dynamic friction.

Therefore, even when tightening with the same torque of 1゜, the tightening (=J-axis force P) will vary greatly (as shown in the figure).

[Problem that the invention seeks to solve]

For the above reasons, even if a washer is used, the axial force due to the rotation of the washer becomes too high, causing the bearing to tighten, resulting in a reduction in engine function, and even leading to bolt failure. There is something. To prevent this, you must use bolts with a large size.
This was a factor in increasing costs, and since the burr surface is generated on the seat surface of the object to be fastened, the rotation thereof generates shavings, which has the disadvantage that the above-mentioned problems cannot be completely prevented.

Focusing on preventing the washer from rotating by making the friction coefficient on the bolt seat side of the washer smaller than the friction coefficient on the tightened side of the washer, it is possible to apply lubricating oil etc. to only one side of the washer. However, with such a liquid, oil would adhere to the other side when the washer was transported or pushed into the bolt, making it impractical and unsuitable for practical use. there were.

[Means for solving problems]

The present invention has been made by focusing on such conventional problems. In order to further reduce the size, the above-mentioned problem was solved by interposing a solid lubricating film coated only on the bearing surface side of the contact surface bolt and nut.

〔Example〕

Hereinafter, the present invention will be explained based on embodiments shown in the drawings.

FIGS. 1 and 2 are diagrams showing one embodiment of the present invention. At the same time, the washer (2°) has a pol I in its center.
It has an inner hole (7) through which the shaft (12) passes, and its outer periphery (8) is generally circular. The surface (9) on the bolt side of the washer and the surface (10) on the fastened object side of the washer are parallel, and the solid lubricant film (11) is formed only on the bolt side surface (9) of the washer (2). It is formed by a coating. This solid lubricant is a fluororesin type (e.g. Teflon (registered trademark) type), molybdenum disulfide type, etc., but the friction coefficient required for this film is different in any case (when oil adheres to the entire washer). However, it goes without saying that the solid lubricating film must be smaller than that of the uncoated surface (10) of the washer on the fastened object side, and it may also be a colored film for identification. It is possible.

FIG. 3 shows an example of the coating process of the solid lubricant film, in which the solid lubricant film is sprayed after pre-cleaning, and the baking process is completed.

Next, the operation will be explained based on FIG.

For the bolt (1), a washer (2'') is attached to the shaft (12), and the bolt-side surface (9) of the washer coated with a solid lubricant film (11) is brought into contact with the pol I/seat surface (5). After being pushed in the direction, it penetrates the object to be tightened (3), is screwed into the female thread member (4), and is tightened with a predetermined tightening torque.The coated solid lubricant film prevents the bolt seating surface from tightening. Since the contact between (5) and washer (2") will be made through solid lubricant, the friction coefficient will be
6), and the uneven surface due to the rotation of Pole l-+1.1 when tightening occurs entirely between Pole l-seat surface part (5) and washer (2゛). That will happen.

Figure 4 shows the relationship between tightening torque and tightening axial force when using the washer of the present invention. The variation in j-axis force P' is small.

Furthermore, in the coating process, the washer may be flowed with one side facing upward in a conveying equipment such as a conhair, sprayed onto the washer, and the washer may be directly transferred to the baking process.

FIG. 5 shows another embodiment of the invention.

In the figure, the washer (2') has an inner hole (7) in the center thereof through which the bolt shaft (12) passes, and its outer peripheral part (8
) is circular. The thickness t of the washer (2°°) is the inner hole (7)
The circular hole is uniform at the outer circumferential portion (8), but the circular hole portion is raised by a height h relative to the outer circumferential portion toward the bolt-side surface (9) of the washer; ) A solid lubricating film (1]) is formed by coating.

The method of use and operation are the same as in the previous embodiment.

Figures 6 and 7 are Naso I (13) or Bolt (1)
A solid lubricant film (
11) is shown coated. Figure 8 shows the object to be tightened using Statpoles 1 to 14 in this example.
The state shown is that it is tightened (=t i) using h(13).

When using the bolt and nut of this example, the washer is tightened using a conventional one, but the usage method and function are Aii.
This is similar to the embodiment described above.

〔Effect of the invention〕

As described above, the present invention has the following effects.

■By interposing a pre-coated solid lubricating film only on the contact surface between the bolt or nut seating surface and the washer, the friction coefficient between them is smaller than the friction coefficient between the washer and the fastened object seating surface. This completely prevents the washer from rotating due to rotation when tightening the bolt or nut, and the lubricating film makes the coefficient of friction extremely stable, which greatly improves the stability of the tightening axial force and at the same time ” No shavings were generated.

■By using a solid lubricant film, the film is less likely to peel off compared to liquid lubricants, so it does not stick to other parts during transportation or assembly, and the difference in friction coefficient can be maintained stably. However, it also has the advantage of retaining its effects even when reused.

■The solid lubricant film has a smaller coefficient of friction than oil lubrication, so even if the film peels off and gets mixed into the lubricant inside the engine, problems such as seizure will not occur.

■Since the solid lubricant film is coated only on the surface that the bolt or nut seat of the washer comes into contact with, the coating process is extremely easy, and the solid lubricant does not scatter or adhere to unnecessary parts. Good yield and excellent mass production.

■In the second embodiment, the bolt and washer can be automatically assembled by creating a dish-shaped configuration in which the inner hole is raised against the outer periphery in the direction of the bolt-side surface of the washer coated with a solid lubricant film. In the automatic washer supply device for use, it is extremely easy to distinguish between the front and back sides of the washer, which has the effect of improving mass production.

■In the third embodiment, if the solid lubricant film is coated on the bearing surface of the Pol I or female screw, it will be completely separated from the member that is intended to cause a difference in the friction coefficient (the washer in this example). Since the friction coefficient difference between the washer surfaces can be completely guaranteed, especially when only the bearing surface of the bolt is coated with a solid lubricant film, when automatically assembling the bolt and washer, it is possible to completely guarantee the difference in the coefficient of friction on the washer surface. This has the effect of improving mass production.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the configuration of the first embodiment of the present invention, and FIG.
Fig. 3 is a process diagram showing an example of the coating process of the solid lubricant film of the present invention, and Fig. 4 is a diagram showing the tightening torque of the present invention and the conventional product. A graph showing the relationship between bolt tightening axial force and FIG. 5 is the second embodiment of the present invention.
6 and 7 are partially cutaway front views showing the third and fourth embodiments of the present invention, and FIGS.
The figure is a partially cutaway front view showing the state of use of the fifth embodiment of the present invention, and FIG. 9 is a sectional view showing a conventional tightening structure. (1): Bolt (2'), (2'') Two washers (3): Tightened object (4): Female thread member (5): Bolt seat (5'') Two nut seat (6) ; Seating surface of the tightened object (7): Inner hole (8): Outer periphery (9): Bolt side surface of the washer (10) n Surface of the washer on the tightened object side (11): Solid lubricant film (12) i-axis part (13): Nasoto (14): Stanod bolt

Claims (2)

[Claims] 1. Attach the bolt (1) to the object to be tightened (3) through the washer (2').
) or a nut (13), the washer (2') and the washer (3) are attached to one side of the contact surface between the bolt (1) or nut (13) and the washer (2). A structure for preventing co-rotation of a washer, characterized in that a solid lubricating film (11) is formed to make the frictional resistance smaller than the frictional resistance of the contact surface with the face part. 2. The co-rotation of the washer according to claim 1, characterized in that at least only the bearing surface portions (5), (5') of the bolt (1) or nut (13) are coated with a solid lubricant film (11). Prevention structure.