JPH05576Y2 - - 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) A piston 51 used in the hydraulic cylinder shown in FIG. 8 is fixed to a piston rod 52 by a female thread 54 screwed into a male thread 53 formed at the tip of the piston rod 52. At this time, the female thread 54
In order to prevent it from loosening due to vibration etc.
As shown in the figure, the female screw 54 is fixed with a set screw 55.

Conventionally, the setting screw 55 has been set as follows. First of all, the male screw 53
After the female thread 54 is screwed together, a screw hole 56 is made in the female thread 54 with a drill. Next, the male screw 53 is countersunk from the screw hole 56 to form a countersunk hole 57 at a position opposite to the screw hole 56. After doing this, the setting screws 55 are set in both holes 56 and 57.

If you attempt to drill the female thread and countersink the male thread before screwing them together, an error will inevitably occur in the dimensions and the screw hole and countersunk hole will not match. For this purpose, the holes are machined after both screws are screwed together as described above.

(Problem to be solved by the invention) However, with this conventional locking structure, chips are generated when countersunking is performed, so after the countersunking process, the female screw must be removed and cleaned. In this way, cleaning work is required after processing, so
The problem was that the number of man-hours required increased accordingly.

Further, the stopping force against loosening of a screw depends on the depth of the countersunk hole 57, but the depth of the countersinking hole 57 tends to vary, which causes a problem such as a large variation in the stopping force. It was hot too.

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

(Means for Solving the Problem) This invention consists of a male thread, an annular groove formed in the threaded portion of the male thread separately from the valley of the thread, a female thread to be screwed into the male thread, and an annular groove formed in the female thread. When both male and female screws are tightened, a hole is formed at a position that is parallel to the diameter line of the male screw, and a wedge member is inserted into the hole. and a locking member that presses the wedge member in the direction of the annular groove, and the opposing interval between the pressing surface of the locking member and the bottom surface of the annular groove formed in the male screw is such that the distance between the pressing surface of the locking member and the bottom surface of the annular groove formed in the male screw is such that the distance between the pressing surface and the bottom of the annular groove is such that It is characterized in that it has a structure that gradually becomes narrower, and that when both screws in a tightened state rotate relative to each other in the loosening direction, the wedge member moves and bites into the bottom surface of the annular groove of the male screw.

(Operation of the present invention) When both screws are tightened, the hole of the female screw and the annular groove of the male screw face each other. In this state, when the wedge member is inserted into the hole and the locking member is screwed together, the wedge member is pushed by the locking member and pressed against the bottom surface of the annular groove and the side surface of the hole.

When an external force in the direction of loosening is applied to the female thread in the above state, the wedge member tends to move in the opposite direction to the direction in which it comes into pressure contact with the side surface of the hole. However, unless the external force overcomes the pressing force of the wedge member against the side surface of the hole, the female thread will not turn in the loosening direction.

Furthermore, even if the female thread overcomes the pressure contact force and rotates, the wedge member is forcibly pushed in the direction in which the facing distance between the pressing surface of the locking member and the bottom surface of the annular groove formed in the male thread becomes narrower. .

As a result of the wedge member being forced into the narrow space, the wedge member bites into the bottom surface of the annular groove. The wedge member that bites into the annular groove within a narrow interval functions to stop the rotation of both screws.

(Effects of the present invention) The female thread will not turn unless the external force acting on the female thread in the loosening direction overcomes the pressing force of the wedge member against the side surface of the hole. Looseness can be completely prevented.

Further, even if the female screw overcomes the pressure force and tries to loosen, the wedge member immediately bites into the annular groove, so that rotation can be prevented within the range of slight loosening (relative rotation) of both screws.

In addition, since it is only necessary to insert the wedge member into the hole formed in the female thread and press this wedge member with the locking member, it is necessary to insert the wedge member into the hole formed in the female thread, so that the screw hole or countersunk hole can be opened while the two screws are screwed together like in the past. Processing becomes unnecessary. In other words, with this invention, the holes and annular grooves into which the wedge members are inserted can be formed in advance, so cutting is not required when assembling them.
Therefore, there is no need for cleaning chips caused by cutting, and work efficiency can be increased accordingly.

(Embodiment of the present invention) In FIGS. 1 and 2, 1 is a piston, 2 is a male thread provided at the tip of a piston rod 3, and has an annular groove 4 of a predetermined width formed therein. 5 is a female screw,
When this female screw 5 is tightened, a hole 6 is formed that faces the annular groove 4. A thread is formed inside the hole 6, and the axis of the hole 6 is located at a position parallel to the diameter line of the piston rod 3.

After inserting the wedge member 7 into the hole 6 thus formed, the locking member 8 is screwed together. And the wedge member 7
As is clear from FIG. 2, an edge A and a convex portion B are formed. Furthermore, a recess is formed in the pressing surface C of the locking member 8.

Furthermore, the axis of this hole 6 is the axis of the piston rod 3.
Since it is located parallel to the diameter line of , when the locking member 8 is inserted into the hole 6 as described above, the opposing distance between the pressing surface C and the bottom surface of the annular groove 4 is , which gradually becomes narrower in the direction of loosening and rotation of the male screw.

Now, while inserting the wedge member 7 into the hole 6,
The edge A is brought into contact with the bottom surface of the annular groove 4. When the locking member 8 is screwed together from this state, the convex surface B of the wedge member 7 coincides with the recess formed in the pressing surface C of the locking member 8, and the edge A of the wedge member 7 is pressed against the annular groove 4. It will be done.

When the male thread 2 or the female thread 5 rotates in the loosening direction E or F, the edge A first bites into the bottom surface of the annular groove 4. When both screws further rotate in this state, the wedge member 7 rolls in the direction shown by the broken line due to the biting resistance of the edge A. Therefore, the biting resistance of the edge A prevents both screws from rotating in the loosening direction.

FIG. 3 shows a second embodiment, in which the wedge member 1
1 is made into a ball, and the pressing surface C of the locking member 12 is formed flat, and other than this point is the same as the first embodiment.

Now, when the female screw 5 tries to rotate in the loosening direction F, the wedge member 11 rotates counterclockwise and moves to the position shown by the broken line due to the pressure contact resistance between the wedge member 11 and the annular groove 4, and the annular groove 4 rotates. It bites into the bottom of 4. Therefore, this biting resistance prevents both screws from rotating in the loosening direction.

FIG. 4 shows the third embodiment, in which the wedge member 2
While flattening the upper and lower surfaces 21a and 21b of 1,
The pressing surface C of the locking member 22 is formed flat,
Other than this point, this embodiment is the same as the first embodiment.

Now, when the female screw 5 tries to rotate in the loosening direction F, the wedge member 21 is pulled to the dotted line position, and the rotation of both screws is stopped by the biting resistance.

FIG. 5 shows a fourth embodiment, in which the pressing surface C of the locking member 25 is formed flat, and the rest is completely the same as the first embodiment.

FIG. 6 shows a fifth embodiment, in which the annular groove 4
The contact surface of the wedge member 31 that comes into contact with the wedge member 31 is inclined, and the inclined surface is made into a sawtooth shape, and the other aspects are the same as in the third embodiment. The principle of inhibiting rotation in the direction of loosening is also the same, and the wedge member 31 is inhibited from rotating when it attempts to move to the position shown by the broken line.

[Brief explanation of drawings]

Figures 1 and 2 show the first embodiment of this invention. Figure 1 is a schematic diagram, Figure 2 is an enlarged sectional view of the main part of Figure 1, and Figures 3 to 6 are other embodiments. FIG. 7 is an explanatory view of the piston fixed with a conventional screw, and FIG. 8 is a cross-sectional view of FIG. 7. 2... Male thread, 4... Annular groove, 5... Female thread,
6... Hole, 7... Wedge member, 8... Locking member, C...
...pressure surface.

Claims (1)

[Scope of utility model registration request] A male thread, an annular groove formed in the threaded portion of the male thread separately from the valley of the thread, a female thread that is screwed into the male thread, and an annular groove formed in the female thread and facing the annular groove when both the male and female threads are tightened. A hole formed at a position parallel to the diameter line of the male screw, a wedge member inserted into this hole, and an engaging member that is screwed into this hole and presses the wedge member in the direction of the annular groove. and a locking member, and the opposing distance between the pressing surface of the locking member and the bottom surface of the annular groove formed in the male screw gradually narrows in the direction of loosening and rotation of the male screw, and both screws in a tightened state are provided. A screw loosening structure characterized in that a wedge member moves and bites into the bottom surface of an annular groove of a male screw when the screw rotates relative to the loosening direction.