JPH0534310U - Lock screw - Google Patents

Abstract

(57) [Summary] [Purpose] A ball that fits in a front seat groove is pressed against an object to be fixed, and a screw for fixing the object is provided with a self-locking function to prevent loosening. Moreover, the self-locking function can be applied to small-diameter screws and is excellent in lock reliability and screw protection effect. [Structure] A tapered tapered hole 4 is continuously provided on the groove bottom side of a front seat groove 2 for fitting and holding a ball 3, and further, a screw 1
A split groove 5 is provided on the tip side of the partition groove to divide the seat groove 2 and the tapered hole 4 into a plurality of portions in the circumferential direction. Ball 3 against opponent material 14
When the ball is pressed against, the ball is pushed into the taper hole 4, the tip side of the screw 1 expands in diameter, and comes into pressure contact with the hole surface of the screw hole provided in the fixing portion 13. Therefore, the frictional force generated in the pressure contact portion prevents the screw from loosening due to vibration or the like. With this structure, there is no processing restriction even when applied to small diameter screws. Further, since the soft filler is not used, the reliability of the lock is high. Furthermore, since no excessive force is applied to the screw, the screw is unlikely to break.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a lock screw for fastening a component having a self-locking function. The screws mentioned here include bolts.

[0002]

[Prior Art]

 Some of the screws used to clamp parts, prevent rotation, etc. are shown in Fig. 4. This screw 10 is one in which a ball 12 is rotatably fitted and held in a spherical seat groove 11 provided on the front surface. The screw 10 is screwed into a screw hole on the fixing portion 13 side to contact the contact surface 12a at the tip of the ball 12. Then, the mating material 14 to be fixed is pressed to set the mating material. Even if the mating member has a bad posture, the contact surface 12a freely changes its direction and comes into close contact with the companion member, so that there is no kinking during tightening and smooth tightening can be performed. However, it does not completely prevent loosening after tightening, and is not suitable for applications that are subject to vibration during use.

On the other hand, there are also screws having a self-locking function for preventing loosening. For example, as shown in FIG. 5, a slit 16 in the radial direction is formed in the center of the thread of the male screw 15 so that the left and right of the thread always contact both sides of the trough of the female thread 17 with pressure. For example, a special filler is wrapped around one side to seal the screw fitting part with the filler and at the same time increase the rotational resistance of the screw.

[0004]

[Problems to be solved by the device]

 If the self-locking function is added to the above-mentioned ball screw, this screw, which ensures smooth tightening, can be used for applications requiring locking.

However, the structure of FIG. 5 in which a slit is formed in the thread of the male screw has a drawback that the female screw is damaged by the male screw. Moreover, since it is premised that the slit can be processed, it cannot be applied to small-diameter screws.

[0006] Further, in the case where the gap of the screw fitting portion is filled with the special filling material wound on one of the fitting surfaces, the loosening preventing effect is not perfect because the filling material is soft, and it cannot be used repeatedly.

Therefore, simply combining conventional techniques does not cause the following four conditions, that is, (1) loosening due to vibration or the like. (2) Can be used repeatedly. (3) Applicable to small diameter screws. (4) Little damage to the screws. It is not possible to obtain a screw with a ball that satisfies all of the above conditions.

Therefore, the present invention seeks to provide a lock screw with a ball that satisfies the above four conditions.

[0009]

[Means for Solving the Problems]

 In the lock screw of the present invention which solves the above-mentioned problems, a tapered taper hole is continuously provided on the groove bottom side of the front seat groove for fitting and holding balls, and further, a seat groove and a taper are provided on the tip side of the screw. It is characterized in that a split groove is provided to divide the super hole forming portion in the circumferential direction.

[0010]

[Action]

 When the lock screw is screwed into the screw hole of the fixed part and the contact surface of the ball tip is pressed against the mating material, the ball is pushed into the taper hole, and the wedge effect expands the seat groove and taper hole formation part of the screw tip. The inner surface of the screw hole. Therefore, the reverse rotation of the screw is prevented by the frictional force generated at this pressure contact, and the natural loosening is eliminated.

Further, since the contact pressure with the hole surface of the screw hole does not increase until the ball hits the mating material, there is no fear of damaging the screw hole. Further, the seat groove and the tapered hole forming portion are prevented from expanding beyond a certain level where the screw hole serves as a control surface, so that the male screw will not be damaged even if an excessive tightening torque is applied.

[0012]

【Example】

 1 and 2 show an embodiment of the present invention. As shown in the figure, the ball 3 is rotatably fitted in the seat groove 2 on the front surface of the screw 1, and the fitted ball 3 is prevented from coming off by slightly narrowing the outlet of the seat groove 2.

Further, a tapered hole 4 having a small diameter on the rear side is continuously provided on the groove bottom side of the seat groove 2, and the ball 3 under no load is received by the spherical surface of the seat groove left on the inlet side of the hole 4. Is done. Reference numeral 5 denotes a split groove vertically cut from the front surface of the screw 1 to a portion where the taper hole 4 is formed. The split groove 5 divides the tip end side of the screw 1 into a plurality of pieces in the circumferential direction.

It is sufficient for the small-diameter screw to divide the tip side into two, but in the case of the large-diameter screw, it is preferable to increase the number of split grooves to facilitate elastic deformation of the screw tip.

The screw shown in FIG. 1 needs to be rotated by engaging the wrench with the wrench hole 6 on the rear surface. However, as shown in FIG. Alternatively, the head may be made non-circular (for example, polygonal) and operated with a spanner.

In addition, as the ball 3, one having a flat contact surface 3a as shown in FIG. 1 or one having a perfect spherical body as shown in FIG. 2 is selected and used according to the application.

As shown in FIG. 3, the screw 1 of the present invention configured as described above is screwed into the screw hole of the fixing portion 13 and presses and fixes the mating member 14 with the ball 3 at the tip. At this time, the ball 3 is press-fitted into the taper hole 4, and the wedge effect by this causes the tip side of the screw having the split groove 5 to expand in diameter and press-contact with the hole surface of the screw hole. Therefore, after tightening is complete, the strong frictional force generated between the outer circumference of the tip of the screw and the hole surface of the screw hole prevents loosening due to vibrations and the like, and the stable fixing state of the mating member is maintained.

[0018]

[Effect of the device]

 As described above, in the screw of the present invention, the ball at the tip becomes a wedge and the diameter on the tip side expands, and the self-locking is performed by the frictional force generated between it and the screw hole. It is said that the ball screw can be used for applications requiring anti-loosening, without being subject to applicable regulations, reducing the protective effect and anti-loosening effect of screws, and not making repeated use impossible. The effect is obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view of another embodiment.

FIG. 3 is a view showing an example of a usage state of the screw of FIG.

FIG. 4 is a diagram showing a conventional ball screw when in use.

FIG. 5 is a sectional view showing a main part of an example of a self-locking screw.

[Explanation of Codes] 1, 10 Screw 2, 11 Seat Groove 3, 12 Ball 3a, 12a Contact Surface 4 Tapered Hole 5 Split Groove 6 Wrench Hole 7 Head 13 Fixing Part 14 Counterpart Material 15 Male Thread 16 Slit

Claims (1)

[Scope of utility model registration request] 1. A lock screw in which a ball to be pressed against an object to be fixed is rotatably fitted in a seat groove on the front surface, and a tapered taper hole is provided continuously on the groove bottom side of the seat groove, and further.
A lock screw, characterized in that a split groove is provided on the tip end side of the screw to divide the formation portion of the seat groove and the tapered hole in the circumferential direction.