JPH0342253Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a structure for locking a screw used in a piston of a hydraulic cylinder, for example.

(Prior Art) Generally, as shown in FIG. 4, a piston 1 used in a hydraulic cylinder or the like is fixed to a piston rod 2 by a female screw 4 screwed into a male screw 3 formed at the tip of the piston rod 2. ing. In order to prevent the female screw 4 from loosening due to vibration or the like, the female screw 4 is fixed with a set screw 5, as shown in FIG.

Conventionally, in order to set the setting screw 5, first the female screw 4 is screwed onto the male screw 3, and then the screw hole 6 is drilled in the female screw 4 with a drill. Next, the male thread 4 is countersunk from the screw hole 6 to form a countersunk hole 7 at a position opposite to the screw hole 6, and the set screw 5 is set in these holes 6, 7.

(Problems to be Solved by the Present Invention) However, since chips are generated during countersunk processing, the female thread must be removed from the male thread for cleaning after countersunk processing, and when reassembled, There was a problem in that the screw holes 6 and the countersunk holes 7 were misaligned.

In addition, the stopping force against loosening of a screw depends on the depth of the countersunk hole 7, but the depth of the countersunk hole 7 tends to vary, which leads to various disadvantages such as increased variation in the stopping force. It was hot.

The object of this invention is to provide a screw locking structure that can eliminate the above-mentioned drawbacks.

(Means for Solving the Problem) In order to achieve the above object, this invention has a male screw in which an annular groove is formed in the threaded portion, and a position opposite to the annular groove when screwed into the male screw. A hole into which the locking member is inserted is provided, a female screw is formed so that the axis of the hole is perpendicular to the axis of the male screw, a locking member inserted into the hole, and one side of the locking member and the annular A lock part is provided between the groove and the lock part which is pressed into contact with the annular groove by a locking member, and the bottom surface of the annular groove and the side surface of the lock member that contacts this bottom surface have a point whose radius of curvature is the same. It has the following characteristics.

(Operation of the present invention) By screwing the male thread into the female thread and pressing the locking member against the annular groove by the locking member, when the male thread or the female thread attempts to rotate in the loosening direction, in other words, both screws When relative rotation is attempted, the locking member rotates. When the lock member rotates in this manner, the edge portion of the lock member bites into the male thread side.

(Effects of the present invention) Since the locking member bites into the annular groove, rotation in the direction of loosening can be reliably inhibited. In addition, since it is sufficient to screw the female thread onto the male thread and press the locking member into contact with the annular groove using the locking member, it is not necessary to provide a screw hole or a countersunk hole after screwing the female thread together as in the conventional method. There is no. Therefore, since no chips are generated due to drilling, etc., work efficiency such as cleaning is not required, and work efficiency can be increased.

Furthermore, since the annular groove is previously provided before the female thread is screwed together, the depth of the annular groove can be made constant, and thereby the force to prevent loosening of the screw can be made constant.

(Embodiment of the present invention) In the first embodiment of the present invention shown in FIGS. 1 and 2, 8 is a piston, 9 is a male thread provided at the tip of a piston rod 10, and an annular groove 11 of a predetermined width is provided.
is preformed.

Reference numeral 12 denotes a female thread, and a hole 13 is provided in advance at a position facing the annular groove 11. And this hole 1
3 is formed so that its axis is perpendicular to the axis of the male thread 9, and a female thread is formed on the inner periphery of the hole 13.

A locking member 15 is screwed into the hole 13, and a locking member 14 is interposed between one side of the locking member 15 and the annular groove 11, and the locking member 15 locks the locking member. The lower surface C of 14 is brought into pressure contact with or bites into the annular groove 11.

In addition, so that the lock member 14 can easily roll,
The lower surface A of the locking member 15 is formed into a concave spherical surface, while the upper surface B of the locking member 14 is formed into a convex spherical surface. Furthermore, the lower surface C of the locking member 14 is shaped like an arc, and the radius of curvature of this arc is equal to the radius of curvature of the bottom surface of the annular groove 11. The lower surface C thus formed has sawtooth-like irregularities formed therein.

Now, when the female screw 12 is screwed onto the male screw 9 and the lower surface C of the locking member 14 is pressed into or bit into the annular groove 11 by the locking member 15, and the female screw 12 tries to rotate in the loosening direction, the annular groove 11 The locking member 14 tends to rotate counterclockwise in the drawing due to the pressure contact resistance between the lower surface C and the lower surface C. And the lower surface C
The left end in the figure digs into the annular groove 11 as shown by the broken line, and rotation in the loosening direction is suppressed by this digging resistance.

In the second embodiment shown in FIG. 3, the lower surface G of the locking member 17 is formed into a concave shape.
The upper surface D of the second embodiment is formed into a convex shape, and the other configurations are the same as those of the first embodiment.

Further, the principle of inhibiting rotation in the direction of loosening is the same, and the locking member 16 rolls as shown by the broken line to inhibit the rotation.

According to the first and second embodiments, when the male thread or the female thread attempts to rotate in the loosening direction, the locking member bites into the annular groove, so that rotation in the loosening direction can be reliably inhibited. Also, since it is sufficient to screw the female thread onto the male thread and press the locking member into contact with the annular groove using the locking member, a screw hole, a countersunk hole, etc. is provided after the female thread is screwed together as in the conventional method. There's no need. Therefore, since no chips are generated due to drilling, etc., work efficiency such as cleaning is not required, and work efficiency can be increased.

Furthermore, since the annular groove is provided in advance before the female thread is screwed together, the depth of the annular groove can be made constant, and thereby the stopping force against loosening of the screw can be kept constant.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the first embodiment of this invention;
The figure is an enlarged sectional view of the main part of Fig. 1, Fig. 3 is an enlarged sectional view of the main part of the second embodiment, Fig. 4 is an explanatory diagram of the conventional piston fixed with a screw, and Fig. 5 is the same as Fig. 4. FIG. 9... Male thread, 11... Annular groove, 12... Female thread, 13... Hole, 14, 16... Lock member, 1
5, 17...Locking member.

Claims (1)

[Scope of utility model registration request] A male screw having an annular groove formed in the threaded portion, and a hole for inserting a locking member at a position opposite to the annular groove when screwed onto the male screw, and the axis of the hole is orthogonal to the axis of the male screw. a locking member inserted into the hole, and a locking member that is pressed into contact with the annular groove by the locking member between one side of the locking member and the annular groove, The bottom surface of the annular groove and the side surface of the locking member that contacts the bottom surface have the same radius of curvature to prevent loosening of the screw.