JP2521484Y2 - Seal structure for sensor protection cover - Google Patents

Description

The present invention relates to a seal structure for a sensor protection cover, and more particularly to a seal structure for a sensor protection cover such as a rotation sensor for detecting the rotation speed of an automobile wheel or the like. It is a thing.

[Prior Art] Conventionally, as such a rotation sensor, for example, a rotation sensor applying a magnet as shown in FIG. 7 is known.

That is, in FIG. 7, the rotation sensor 1 has a tip at the tip of a gear wheel of a magnetic body (not shown) mounted on a rotation shaft of an automobile wheel or the like whose rotation speed is to be detected. A pole piece 2 made of a magnetic material such as iron and arranged in close proximity so as to face each other, a magnet 3 attached to the rear end surface of the pole piece 2 and having a polarity, and the magnet 3 are included. It mainly comprises a coil 5 wound around the tip end of a bobbin 4 arranged around the pole piece 2.

The sensor portion of the rotation sensor 1 is covered with a cylindrical sensor protection cover 6 made of metal such as stainless steel.

In the rotation sensor 1 configured as described above, when the gear is rotating, the tip of the gear is repeatedly approached and separated from the tip of the pole piece 2, so that the tip of the pole piece 2 is separated from the gear. The distance to the nearest part of will alternately increase or decrease. As a result, the number of magnetic lines of force passing through the pole piece 2 is increased or decreased to change the magnetic flux, and thus an AC voltage is generated in the coil 5, the frequency of which is the number of tooth tips of the gear passing through the tip of the pole piece 2. And is equal to the product of the number of revolutions.

Thus, the AC voltage is taken out through the lead wire 7 and the frequency thereof is measured to detect the rotation speed of the rotating shaft to which the gear is attached, which allows various controls such as engine control and skid control of automobiles. It is being used for control.
In the figure, 8 is a terminal.

By the way, as described above, the sensor unit 1a such as the rotation sensor 1
Is covered with a sensor protection cover 6, but in order to prevent rainwater and the like from entering the sensor unit 1a when it is adopted in, for example, an automobile, the protection cover 6 is conventionally provided with the following seal structure. Was there.

That is, a ring groove 10 is formed on the base end side of the sensor portion 1a along the circumferential direction thereof, an O-ring 11 is positioned in this groove, and the sensor portion 1a is covered with the protective cover 6 described above. The O-ring 11 is positioned by pressing it from the outside inward in the radial direction with a caulking sealing device (not shown).

Then, the convex portion of the caulking tool of the caulking sealing device covers the cover 6
Is pressed from the outside to be curved inward and the inner diameter is narrowed, and the projection 6a comes into contact with the center of the O-ring 11 to fix and seal it.

[Problems to be solved by the device]

However, the above-described seal structure of the sensor protection cover has the following problems.

The fixing of the O-ring 11 by caulking the protective cover 6 is a work performed from the outside of the protective cover 6 regardless of the caulking sealing device. At this time, it is difficult to determine the position where the O-ring 11 is provided. The center of the O-ring 11 is the above-mentioned protrusion 6a.
There was a problem that it was easy to run away from the center of.

Further, in the crimping work, the O-ring 11 is caused due to variations in the dimensions of the sensor portion 1a, the protective cover 6, and the like.
Misalignment, or the protrusion 6a as shown in FIG.
Is partially abutted on the O-ring 11, the O-ring 11
Was twisted and could not be completely sealed.

Further, the protrusion 6a of the protective cover 6 is attached to the O-ring.
In order to make it easy to contact the vicinity of the center of 11, the O-ring 11
However, there is a problem in that the ring groove must be deepened.

Then, as shown in FIG. 9, it is possible to cope with the displacement of the O-ring 11 with respect to the protrusion 6a by using a special O-ring 11a having a constricted central portion. There is a problem that the special O-ring 11a is expensive.

In view of the above points, the present invention makes it possible to inexpensively provide a seal structure for a sensor protection cover, which can prevent the O-ring from being displaced or twisted in the crimping work of the sensor protection cover to improve the reliability of the seal. The purpose is to provide.

[Means for solving the problem]

According to the seal structure of the sensor protective cover of the present invention, a ring groove having a rectangular cross section is formed in the base end portion of a sensor portion such as a rotation sensor along the circumferential direction, and the sensor is provided in the ring groove. Two or more O-rings are juxtaposed in the longitudinal direction of the portion, the sensor portion including the O-rings is covered with a sensor protective cover, and the portion between the O-rings of the protective cover is pressed radially inward from the outside. It is achieved by caulking.

[Action]

According to the above configuration, two or more O-rings are juxtaposed in the longitudinal direction of the sensor section such as the rotation sensor in the ring groove formed in the base end section of the sensor section, and the sensor protection including the O-ring is covered. The portion between the O-rings of the cover is pressed from the outside inward in the radial direction to perform the caulking sealing.

Therefore, for example, when a caulking sealing device is used, the convex portion of the caulking tool presses the protective cover from the outside and bends inwardly, and the protruding portion having the narrowed inner diameter is interposed between the O-rings. The O-ring is displaced from the center of the protrusion on both sides in the longitudinal direction of the sensor unit. At this time, since the ring groove has a rectangular cross section, each O-ring is retained inside the ring groove and deforms without being twisted, so that the gap between the sensor unit and the protective cover can be sealed. The reliability of the seal is improved.

Also, since a standard O-ring can be used,
Even if the production number of the rotation sensor is small, it is possible to cope with this and it is inexpensive.

〔Example〕

Hereinafter, an embodiment of a seal structure for a sensor protection cover of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the rotation sensor 1 comprises a sensor portion 1a and a holder portion 1b.

In the sensor section 1a, a tip is opposed to a tooth tip of a magnetic rotating gear (not shown) mounted on a rotating shaft of an automobile wheel or the like whose rotational speed is to be detected. A pole piece 2 made of a magnetic material such as iron and arranged in close proximity, a magnet 3 attached to the rear end surface of the pole piece 2 with a polarity, and the circumference of the pole piece 2 including the magnet 3. The coil 5 wound around the front end side of the bobbin 4 arranged in is mainly provided.

Further, a lead wire 7 is provided on the holder portion 1b.

A ring groove 20 is formed along the circumferential direction of the base end portion of the sensor portion 1a on the holder portion side. As shown in FIG. 2, the ring groove 20 has a rectangular cross section.

In this embodiment, two identical O-rings 11 are juxtaposed in the ring groove 20 in the longitudinal direction of the sensor portion 1a. A standard type O-ring 11 having a circular cross section is adopted.

The sensor portion 1 a including these O-rings 11 is covered with the sensor protection cover 6. As shown in FIG. 3, the protective cover 6 has a cylindrical shape with one end closed, and is made of metal such as stainless steel.

The sensor portion 1a having the two O-rings 11 juxtaposed in the ring groove 10 is inserted into the protective cover 6.

The portion between the O-rings 11 of the protective cover 6 is pressed inward in the radial direction from the outside and is caulked and sealed.

Specifically, for example, a caulking sealing device (not shown) or the like is used, and the convex portion of the caulking tool presses the protective cover from the outside so that the peripheral wall of the protective cover 6 is curved inward and the inner diameter is increased. And the O-ring 11 is caulked and sealed.

 Next, the operation of the above embodiment will be described.

As described above, a ring groove is formed in the base end portion of the sensor portion 1a of the rotation sensor 1 along the circumferential direction thereof. First, two O-rings 11 are juxtaposed in the ring groove 20 in the longitudinal direction of the sensor unit 1a, and the sensor unit 1a including the O-ring 11 is inserted into the cylindrical sensor protection cover 6. Next, using, for example, a caulking sealing device, the O-ring of the sensor protection cover 6 is caused by the convex portion of the caulking tool.
A portion between 11 is pressed inward in the radial direction from the outside to be curved inward to form a protrusion 6a having a reduced inner diameter, which is caulked and sealed.

That is, as shown in FIG. 4, since the protrusions 6a of the protective cover 6 are interposed between the O-rings 11, each O-ring 11 extends from the center of the protrusion 6a in the longitudinal direction of the sensor unit 1a. It will shift to both sides. At that time, the ring groove 20
Since the cross section of is rectangular, each O-ring 11 is
It is held inside 20 and is deformed in the ring groove 20 without being twisted, so that the gap between the sensor portion 1a and the protective cover 6 can be surely sealed.

Further, in the seal structure of this embodiment, since the two O-rings 11 are juxtaposed in the ring groove 20, the seal structure is also configured as a double seal structure.

Therefore, due to these synergistic effects, the reliability of the seal of the rotation sensor is significantly improved.

Further, as shown in FIG. 5, the ring groove 20
When the two O-rings 11 are juxtaposed inside each other, the caulking effective width S is between the center of the upper O-ring 11b and the center of the lower O-ring 11c. This is the protrusion 6a of the protective cover 6 described above.
Even if the center of the upper O-ring 11b contacts the center of the upper O-ring 11b, or the center of the protrusion 6a contacts the center of the lower O-ring 11c, the upper or lower O-rings 11b, 11c are effectively caulked. Because it will be sealed.

Next, as shown in FIG. 6, in the conventional seal structure, the cross-sectional diameter of the O-ring 11 had to be increased in order to increase the effective crimping width S. In the embodiment, since the effective crimping width S is increased by arranging the two O-rings 11 side by side in the ring groove, the ring groove 20 is larger than the conventional ring groove 10.
The depth of can be made shallower and the crimping position can be set easily.

Further, since the seal structure of the sensor protection cover of the present embodiment can be configured by using the standard O-ring 11, even if the production number of the rotation sensor 1 is small, it is possible to cope with this. It is cheap.

The seal structure of the sensor protection cover of the present invention can be applied to other sensors having the sensor protection cover 6 other than the rotation sensor 1, and is formed by pressing the protection cover 6. When two or more protrusions 6a are formed, a mode in which the number of the O-rings 11 is increased according to the number of the protrusions 6a is also conceivable.

[Effect of device]

As described above, according to the seal structure of the sensor protective cover of the present invention, it is possible to prevent the O-ring from being displaced or twisted during the crimping work of the cover, and to improve the reliability of the seal. It has an excellent effect that it can be provided at low cost.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of a seal structure of a sensor protective cover of the present invention, FIG. 2 is a side view showing a sensor portion and an O-ring provided at a base end portion thereof, and FIG. FIG. 4 is a side sectional view showing a cover, FIG. 4 is a side sectional view showing an essential part of FIG. 1, FIG. 5 is a schematic view showing a caulking effective width of a seal structure of a sensor protective cover of the present invention, and FIG. It is a schematic diagram showing explanation by comparing a seal structure of a sensor protection cover of the device with a conventional structure. FIG. 7 is a side sectional view showing a seal structure of a conventional sensor protection cover, FIG. 8 is a schematic view showing a twisted state of a conventional O-ring, and FIG. 9 is a schematic view showing a conventional special O-ring. . 1 ... Rotation sensor; 1a ... Sensor part; 1b ... Holder part; 6 ...
… Protective cover; 6a… Projection; 11… O-ring; 20… Ring groove; S… Effective crimping width.

Claims (1)

(57) [Scope of utility model registration request] 1. A ring groove having a rectangular cross section is formed along a circumferential direction of a base end portion of a sensor portion such as a rotation sensor, and two or more O-rings are juxtaposed in the ring groove in the longitudinal direction of the sensor portion. The sensor portion including the O-ring is covered with a sensor protective cover, and the portion between the O-rings of the protective cover is pressed radially inward from the outside to perform caulking and sealing. Cover seal structure.