JPS608173Y2 - Shaft locking device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shaft retaining device that prevents a shaft moving within a bearing from being easily pulled out in the axial direction.

For example, a record player is equipped with a center shaft that supports a turntable, and this center shaft is rotatably supported by a bearing attached to a player board so as not to come off in the axial direction.

By the way, the structure that prevents the shaft from being pulled out as shown in the bearing is
As shown in FIGS. 1 to 5, this causes a problem of obstructing smooth rotation of the shaft.

FIG. 1 shows a substantially cylindrical body made of an alloy that constitutes a bearing 1.
First, a shaft hole 2 is drilled through the center of the cylindrical body using a drill or a cutting tool, and then a pilot hole 3 is drilled perpendicularly to the shaft hole 2 from the circumferential surface of the cylindrical body.

Next, a screw thread is inserted into the pilot hole 3 and a tap is formed.Through the forming of the tap hole 4, the end of the tap hole 4 on the side facing the shaft hole 2 is formed as shown in Fig. 3. As shown, the burr 5 protrudes.

Since this burr 5 prevents the insertion of the center shaft into the shaft hole 2, the shaft hole 2 is again subjected to pole burnishing to crush its inner surface, and as a result, the inner surface is smoothed and the burr is 5 is pushed back into the tap hole 4 as shown in FIG.

Therefore, the diameter of the screw hole becomes smaller at the portion where the tapped hole 4 faces the open end of the shaft hole 2.

In this state, the center shaft 6 is inserted into the shaft hole 2, and the screw 8 is inserted into the tapped hole 4 toward the groove 7 provided on the outer periphery of the center shaft 6 to prevent removal.
When screwed into the groove 7, the burr 9 pushed back as described above
I fall inside.

Therefore, although the end of the screw 8 faces the concave groove 7 and the center shaft 6 is prevented from being removed from the bearing 1, the burr 9 that has fallen into the concave groove 7 enters the bearing sliding surface and prevents the rotation of the center shaft 6. There are problems such as instability, generation of vibration and noise, and seizure of these sliding surfaces.

The present invention was developed in view of such conventional problems, and after forming the shaft hole, a pilot hole penetrating the shaft hole is drilled from the outer periphery of the cylindrical body to shape the bearing. After the inner surface of the pole is burnished, the shaft is inserted into the hole, and a forming screw with a small diameter portion at the tip is screwed directly into the prepared hole toward the concave groove on the outer periphery, making it easy to prevent the shaft from being pulled out. It is an object of the present invention to provide a novel shaft removal prevention device that can be implemented at low cost in a process and can smoothly rotate the shaft without any hindrance.

An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 6 to 8 specifically show the formation sequence of the shaft removal prevention device according to the present invention.

FIG. 6 shows a substantially cylindrical body made of alloy that constitutes the bearing 10. First, a shaft hole 11 is drilled in the center of this with a drill or the like, and then a hole is penetrated into the shaft hole 11 from the outer peripheral surface. The pilot hole 12 is drilled in the same manner as described above.

At this time, a burr 13 protrudes from the side of the pilot hole 12 facing the shaft hole 11, but due to the pole burnish finishing of the inner surface of the shaft hole 11 as described above, the burr 13 is pushed into the pilot hole 12 as shown in FIG. I was pushed back like that.

As a result, the inner diameter of the portion of the lower hole 12 facing the shaft hole 11 becomes somewhat smaller.

Next, the center shaft 14 is inserted into the shaft hole 11, and a forming screw having a small diameter portion 16 whose tip end is smaller than the diameter of the prepared hole 12 where the burr 13 is located is inserted toward the groove 15 on the outer periphery for preventing removal. 17 is directly screwed into the prepared hole 12.

Note that the length of the small diameter portion 16 is made shorter than the depth of the groove 15.

Then, as shown in FIG.
Although the center shaft 14 is allowed to rotate by facing into the groove 15 without contacting the bearing 10 of this
axial withdrawal is restricted.

In this way, it is possible to prevent accidents such as the burr 13 remaining in the groove 15 and interfering with the rotation of the center shaft 14, making it unstable, or seizing the sliding part.

FIG. 9 is a partially longitudinal sectional front view showing the relationship between the bearing 10 and the center shaft 14, which shows such a pull-out prevention relationship.

In the figure, 18 and 19 are disc-shaped nylon plates and iron plates that are sequentially inserted from the bottom of the shaft hole 11 of the bearing 10,
These are inserted from the lower part of the shaft hole 11, and the shaft hole 1
It is supported by a C-shaped elastic ring 20 that is locked in a narrow annular groove provided in the inside.

Further, a notch (not shown) is provided at the center of the lower end of the center shaft 14 inserted into the shaft hole 11 of the bearing 10, and a steel ball 21 is press-fitted into this notch. is supported by.

In this way, the center shaft 14 is smoothly supported within the bearing 10, and is prevented from freely pulling out.

The shaft removal prevention structure described above can also be applied to a device for raising and lowering the tone arm lid shaft with respect to the bearing.

In such a case, the annular groove formed on the outer periphery of the lifter shaft faces the outside of the bearing, thereby preventing leakage of damper oil intended for braking the lifter shaft.

In summary, according to the present invention, there is provided a bearing having a shaft hole into which the shaft is inserted, a shaft inserted into the bearing and having a groove on its outer periphery, and a transparent shaft provided at a predetermined position of the bearing corresponding to the groove. A forming screw having a small diameter portion smaller than the inner diameter of the opening hole at the tip thereof is screwed into the opening hole, and the small diameter portion of the forming screw prevents the shaft from being pulled out. Therefore, an inexpensive shaft removal prevention device can be obtained with a simple process and configuration.

In this way, it is possible to reliably prevent accidents in which chips such as burrs remain on the bearing surface and the rotation of the shaft is hindered or becomes unstable, as in the conventional case.

[Brief explanation of drawings]

1 to 5 are explanatory diagrams showing the order of forming a conventional shaft removal prevention device, and FIGS. 6 to 8 are explanatory diagrams showing the order of forming a shaft removal prevention device according to the present invention. 9 are partially longitudinally sectional front views showing the attachment structure of the center shaft to the bearing. 10...Bearing, 11...Shaft hole, 12.
...Opening hole, 14...Shaft, 15...
...concave groove, 16...small diameter part, 17...
forming screw.

Claims (1)

[Scope of utility model registration request] The bearing has a shaft hole into which the shaft is inserted, a shaft that is inserted into the bearing and has a groove on its outer periphery, and an opening hole provided in the bearing to correspond to the groove, and the shaft has the shaft hole at the tip. A forming screw having a small diameter part smaller than the inner diameter of the opening hole is screwed into the opening hole, and the small diameter part faces into the groove to prevent the shaft from being removed from the bearing. Stop device.