JPH0739151Y2 - Limit switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Application Field >> The present invention relates to a limit switch having an improved roller lever bearing structure.

<< Prior Art >> Conventionally, as an enclosed type limit switch in which a switch main body is built in a box, for example, one described in Japanese Utility Model Laid-Open No. 61-83229 is known.

The conventional limit switch described above has a rotating shaft a as shown in FIG. 4 which is rotatably supported by a box through a bearing portion.
A roller lever (not shown) is fixed to one end of the rotary shaft a. Further, a cam portion b is provided on the other end side of the rotary shaft a, and when the rotary shaft a is rotated by a roller lever, the cam portion b is housed in the box via the plunger (whichever is the main body). Is also configured to operate the rotary shaft a
A bearing (not shown) for supporting the bearing has a groove formed in a spiral shape so that the grease supplied to the bearing portion is diffused to the entire sliding portion of the rotary shaft a by the groove. Has become.

<Problems to be solved by the invention> However, in the case where the spiral groove is formed on the inner surface of the bearing as in the conventional case, since the length of the groove is long, the grease supplied to the groove has the entire sliding portion. It took a long time to be diffused into the surface, and during this time there was a problem that oil was run out at the sliding part and abnormal wear or seizure occurred.

Further, since it is difficult to form the spiral groove, it takes a lot of man-hours to manufacture the bearing, resulting in an increase in cost.

The present invention has been made in order to improve the above-mentioned problems, and an object thereof is to provide a limit switch, in which the rotatability of the roller lever is good, at a low cost.

<Means for Solving the Problems> In order to achieve the above-mentioned object, the present invention provides a cam portion on the other end side of a rotary shaft rotated by a roller lever attached to one end side, and the cam portion provides a plunger. Also, in a limit switch that operates the switch body inside the box via the auxiliary plunger, an oil sump is provided along the axial direction on the outer peripheral surface of the rotary shaft, and the grease injected into this oil sump causes the rotation shaft The sliding surface of the bearing that supports this is lubricated.

<Operation> As a result, compared to the conventional bearing with spiral grooves formed on the inner surface, the grease spreads more quickly over the entire sliding surface, resulting in good rotation and long-term use. However, there is little risk of abnormal wear or seizure due to running out of oil.

<< Embodiment >> An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view of a limit switch according to an embodiment of the present invention, FIG. 2 is a perspective view of a rotary shaft, and FIG. 3 is a perspective view of the rotary shaft seen from another direction.

In FIG. 1, reference numeral 1 is a box, and a bearing 3 is fitted to a head portion 2 of the box 1, and a rotary shaft 4 is rotatably supported by the bearing 3.

As shown in FIGS. 2 and 3, the rotary shaft 4 has a small diameter portion 4a having a spline formed at one end thereof,
A roller 5 is rotatably supported by the base end of a roller lever 6 which is rotatably supported at the tip of the small diameter portion 4a.

Further, an annular groove 4b for fitting the O-ring 7 is formed on the side of the small diameter portion 4a, and a part of the outer peripheral surface is chamfered in a rectangular shape in the axial direction in the middle portion, so that an oil sump is formed.
4c is formed.

When the rotary shaft 4 is fitted into the bearing 3, the oil sump 4c forms a space having a substantially half-moon shape in cross section with the inner surface of the bearing 3, and when assembled in the oil sump 4c, grease is formed. Is to be injected.

On the other hand, a cam portion 4d is formed on the other end side of the rotary shaft 4 at a position eccentric from the shaft center, and a plunger 8 housed in the head portion 2 of the box 1 contacts the upper surface of the cam portion 4d. Has been done.

The plunger 8 is pressed against the cam portion 4d by the compression spring 9, and when the rotary shaft 4 is rotated by the roller lever 6, the cam portion 4d pushes up the plunger 8 to compress the compression spring 9. ing.

Another plunger 10 is in contact with the lower surface of the cam portion 4d.

The plunger 10 is in contact with the upper end of an auxiliary plunger 11 movably supported in the box 1 via a spring 11a, and the lower end of the auxiliary plunger 11 is in the box 1
It is connected to the operating portion of the switch body 12 housed inside.

In the figure, 13 is provided on the upper part of the auxiliary plunger 11,
This is a seal cap that prevents grease from entering the switch body 12 side in the box 1 from the rotating shaft 4 side.

Next, the operation will be described. The bearing 3 provided in the head portion 2
The oil sump 4c formed on the rotary shaft 4 when the rotary shaft 4 is assembled into the
When the rotary shaft is rotated by the roller lever 6 when grease is preliminarily injected into the grease, the grease enclosed in the oil sump 4c slides between the rotary shaft 4 and the inner surface of the bearing 3 as the rotary shaft 4 rotates. The surface is diffused and the sliding surface is lubricated.

As a result, good rotatability is obtained, and the rotation of the rotary shaft 4 causes the cam portion 4d to immobilize the auxiliary plunger 11 via the plunger 10, so that the switch body 12 in the box 1 is operated.

When the roller lever 6 is released, the cam section 4d
Compression spring 9 that was compressed by the plunger 8 by
By this action, the rotary shaft 4 is returned, the roller lever 6 is returned to the original position, and the switch body 12 is also turned on (or off).

<Effects of the Invention> As described in detail above, the present invention has an oil sump provided on the outer peripheral surface of the rotary shaft, and the grease injected into the oil sump lubricates the sliding surfaces of the rotary shaft and the bearing. Therefore, compared to the conventional bearing with spiral grooves formed on the inner surface, the grease in the oil sump diffuses more quickly over the entire sliding surface, resulting in good rotation and abnormal oil shortage. Since it is possible to prevent wear and seizure, the life is greatly improved.

Also, since the oil sump is provided on the rotating shaft side,
Since it is easier to process as compared with the conventional one in which a spiral groove is formed on the inner surface of the bearing, it can be provided at a low cost.

[Brief description of drawings]

1 is a sectional view of a limit switch, FIGS. 2 and 3 are perspective views of a rotary shaft, and FIG. 4 is a perspective view of a conventional rotary shaft. 1 ... Box, 3 ... Bearing, 4 ... Rotary shaft, 4c ... Oil sump, 4d
… Cam section, 10… Plunger, 11… Auxiliary plunger, 12…
Switch body.

Claims (1)

[Scope of utility model registration request] 1. A cam portion is provided on the other end side of a rotary shaft rotated by a roller lever attached to one end side, and the cam body operates a switch main body in a box via a plunger and an auxiliary plunger. In this limit switch, an oil sump is provided along the axial direction on the outer peripheral surface of the rotary shaft, and the grease injected into the oil sump lubricates the rotary shaft and the sliding surfaces of the bearings that support it. Limit switch.