JPH10253645A - Rotational frequency sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a sensor from degrading without loosening of the bearing by providing a groove part for the outer surface of the bearing of a cylindrical part. SOLUTION: The first and second bearings 33 and 34 are each insert-molded to the cylindrical part 32 of a case 31. Screw grooves 37 and 39 are provided for the bearings 33 and 34, respectively, while leaving the upper and lower ends of the bearings 33 and 34 with unmolded parts 36 and 38. By this, even when a magnet 42 is rotated together with the rotation of a counter shaft 47 inserted into the cylindrical part 32, the bearings 33 and 34 are not rotated together as the screw grooves 37 and 39 each prevent sliding. Therefore, as there is not possibility that the bearings 33 and 34 come loose, it is possible to improve the characteristics of a rotational sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation speed sensor used for detecting the speed of an automobile or the like.

[0002]

2. Description of the Related Art A conventional rotational speed sensor is disclosed in Japanese Patent Laid-Open No. 8-35.
The one disclosed in Japanese Patent Application No. 977 is known.

Hereinafter, a conventional rotation speed sensor will be described with reference to the drawings. FIG. 6 is a cross-sectional view of a conventional rotation speed sensor, and FIG. 7 is an assembled perspective view showing a fitting state of a magnet and a bearing, which are main parts of the conventional rotation speed sensor.

In FIGS. 6 and 7, reference numeral 1 denotes a case,
A cylindrical portion 3 having a bearing 2 at an upper portion of an inner side surface, and a storage recess 4 is formed at an upper end of the cylindrical portion 3. Reference numeral 5 denotes a cylindrical magnet, which is provided above the shaft portion 6 fitted to the bearing 2 of the case 1 and is disposed in the storage recess 4 of the case 1. Reference numeral 7 denotes a cover, inside which a magneto-electric conversion element (not shown) is provided and the case 1
Of the storage recess 4 is closed.

The operation of the conventional rotation speed sensor having the above-described configuration will be described below with reference to the drawings.

The magnet 5 rotates with the rotation of the mating shaft 9 attached to the lower end of the shaft portion 6 via the connecting shaft 8. As the magnet 5 rotates, the magnetic field around the magnet 5 changes. Then, the change in the magnetic field is detected by a magneto-electric conversion element provided on the cover 7, and the electric signal is output to an indicating instrument (not shown) of an external device to perform a predetermined speed display. .

[0007]

However, in the above-mentioned conventional construction, the bearing 2 provided on the upper portion of the inner surface of the cylindrical portion 3 rotates and rotates together with the rotation of the magnet 5, so that the characteristic of the rotation speed sensor is obtained. Had a problem of deterioration.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a rotation speed sensor in which a bearing does not loosen.

[0009]

In order to achieve the above object, a rotation speed sensor according to the present invention is provided with a portion where a screw groove is formed and a portion where a screw groove is not formed in the middle of the outer surface of the second bearing. It is configured.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention has a first bearing at an upper end of a cylindrical portion, a second bearing at a lower end of the cylindrical portion, and an upper end of the cylindrical portion. A case formed with a storage recess, a cylindrical magnet provided at an upper portion of a shaft portion fitted to the first bearing of the case, and disposed in the storage recess of the case; A guide portion for storing the magnet in the storage recess of the case, which is provided so as to close an opening of the storage recess, and a storage portion arranged in parallel with the guide portion; An electronic circuit board including a cover including a connector portion having a connector terminal provided above, and a magnetic sensing element fixed to a storage portion of the cover and electrically connected to the connector terminal of the connector portion of the cover. And the second bearing Since the portion where the screw groove is formed and the portion where the screw groove is not formed are provided in the middle of the side surface, the second bearing rotates together with the rotation of the magnet and has the effect of not being loosened. .

According to a second aspect of the present invention, a first bearing is provided at an upper end of a cylindrical portion, a second bearing is provided at a lower end of the cylindrical portion, and a storage recess is provided at an upper end of the cylindrical portion. And a cylindrical magnet provided on the upper part of the shaft part fitted to the first bearing of the case and disposed in the storage recess of the case, and a storage recess of the case. A cylindrical guide portion that is provided so as to close the open portion and that stores the magnet in the storage recess of the case and protrudes downward, and a storage portion that is juxtaposed to have an opening surface on the opposite side to the guide portion. And a connector including a connector portion provided above the guide portion and the storage portion, the connector portion having a connector terminal protruding from the storage portion, and a connector of the connector portion of the cover fixed to the storage portion of the cover. Electrically with terminals And an electronic circuit board including a continuous magnetic sensing element, and a screw groove forming portion and a screw groove non-forming portion are provided in the middle of the outer surface of the second bearing. The bearing has the effect that the bearing does not come loose with the rotation of the magnet.

According to a third aspect of the present invention, at least one oil flow groove is provided on the lower end face of the second bearing according to the first or second aspect from the center outward. This has the effect that oil does not accumulate inside and the characteristics of the sensor do not deteriorate.

According to a fourth aspect of the present invention, a polygonal portion is provided below a magnet forming portion of a shaft portion provided with the magnet according to the first or second aspect, and a hole having the same shape as the polygonal portion is provided. And the washer is fitted into the polygonal portion of the shaft portion and slidably contacts the first bearing. Therefore, the magnet and the washer are firmly fixed, and the washer is detached from the magnet by rotation of the magnet. Has the effect of not having

(Embodiment) A rotation speed sensor according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view of a rotation speed sensor according to an embodiment of the present invention, FIG. 2 is a sectional side view of the same, FIG. 3 is a perspective view of a first bearing which is a main part of the same, and FIG. The second part that is the main part
FIG. 5 is a perspective view of a washer which is a main part of the bearing.

In FIGS. 1 to 5, reference numeral 31 denotes a case made of a resin such as polybutylene terephthalate (hereinafter referred to as "PBT").
And a second bearing 34 at the lower end of the cylindrical portion 32.
And a storage recess 35 at the upper end of the cylindrical portion 32. The first bearing 33 is provided with a screw groove 37 so as to have an unformed portion 36 at an upper end and a lower end, and the second bearing 34 is similarly screwed so as to have an unformed portion 38 at an upper end and a lower end. A groove 39 is provided. From substantially the center of the outer surface of the cylindrical portion 32, a mounting portion 41 integrally formed with a metal mounting bracket 40 protrudes outward. Reference numeral 42 denotes a magnet, and a shaft 43 provided so as to be fitted to the first bearing 33.
And has a concave portion 44 on the upper surface. A hexagonal portion 45 is provided above the shaft portion 43, and the shaft portion 43 is connected to a mating shaft 47 via a connecting shaft 46. Reference numeral 48 denotes a metal washer having a hexagonal hole 49 at substantially the center thereof. The hole 49 fits with the hexagonal portion 45 of the magnet 42 and is formed between the first bearing 33 and the lower surface. Is in sliding contact. Reference numeral 50 denotes a substrate made of ceramic or the like, which is provided with a magnetoelectric conversion element 51 such as a Hall IC and an electronic circuit 52, and has a terminal 53 electrically connected to the electronic circuit 52. Numeral 54 is a cover made of resin such as polybutylene phthalate, which is provided so as to close the opening of the storage recess 35 of the case 31, and is a cylinder for storing the magnet 42 in the storage recess 35 of the case 31. A guide part 55 protruding downward in a shape, a storage part 56 having an opening surface on a side opposite to the guide part 55 and opposite to the guide part 55, and having the substrate 50 fixed thereto, Part 5
5 and a connector section 57 provided on the upper surface of the storage section 56. A connector terminal 58 is provided inside the connector terminal 58, one end of the connector terminal 58 protrudes upward, and the other end is electrically connected to the terminal 53 of the substrate 50 by the housing 56. The opening surface of the storage section 56 to which the substrate 50 is fixed is sealed with a sealing resin 59. 60
Is a coil spring, which is assembled in a compressed state between the concave portion 44 of the magnet 42 and the guide portion 55 of the cover 54, and a stud 61 is mounted on the coil inner diameter at the upper end of the coil spring 60. Is placed. A metal receiving plate 62 is fixed to the upper end of the guide portion 55 of the cover 54, and the upper end portion 63 of the stud 61 is in sliding contact.

The assembling method of the rotation speed sensor according to the embodiment of the present invention configured as described above will be described below.

First, the case 31 having the cylindrical portion 32 in which the first bearing 33 and the second bearing 34 are insert-molded is prepared in advance. Next, the washer 4
8 is the shaft portion 4 integrally formed with the magnet 42.
3 and the shaft portion 43 is mounted so as to be fitted to the first bearing 33 of the cylindrical portion 32. Next, the coil spring 60 having the stud 61 mounted on the upper end thereof is placed in the concave portion 44 of the magnet 42. Next, the magnetoelectric conversion element 51 and the electronic circuit 52 are mounted on the substrate 50 and soldered in a reflow furnace.

Next, the substrate 50 is housed in the housing portion 56 of the cover 54, and the terminals 53 are soldered to the connector terminals 58. At this time, since the storage section 56 has an opening surface on the opposite side to the guide section 55, the storage section 56 has an effect that soldering is easy. Next, the sealing resin 59 is filled in the storage portion 56 of the cover 54, and the sealing resin 59 is poured into a high-temperature bath at about 120 ° C. for about 1 hour to cure the sealing resin 59. Finally, the receiving plate 62 is inserted into the upper surface of the guide portion 55 of the cover 54, and the cover 54 is inserted into the guide portion 55 so that the magnet 42, the coil spring 60, and the stud 61 are housed therein.
The upper surface opening of the case 31 is sealed.

The operation of the rotational speed sensor constructed and assembled as described above according to one embodiment of the present invention will be described below with reference to the drawings.

1 and 2, the magnet 42 rotates with the rotation of the mating shaft 47 inserted into the cylindrical portion 32. The rotation of the magnet 42 changes the magnetic field around the magnet 42. Then, the change in the magnetic field is detected by the magnetoelectric conversion element 51 and the electronic circuit 52 provided on the substrate 50, and the electric signal is output to an indicating instrument (not shown) of an external device to display a predetermined speed. It is supposed to do.

Here, a case where the magnet 42 rotates with the rotation of the mating shaft 47 will be considered. As shown in FIGS. 3 and 4, the first bearing 33 has screw grooves 3 so as to have unformed portions 36 at the upper and lower ends.
7, and the second bearing 34 is also provided with screw grooves 3 so as to have unformed portions 38 at the upper and lower ends.
9, the screw groove 37 and the screw groove 39 are prevented from rotating even when the magnet 42 rotates with the rotation of the mating shaft 47, and the first bearing 33 and the second Have the effect that the bearings 34 do not rotate together.

The rotation speed sensor is usually mounted on the mounting portion 4.
1 is used in a state where the engine oil is filled up to the lower surface. Here, if the engine oil reaches the magnet 42 of the guide portion 55 of the cover 54, the characteristics of the rotation speed sensor deteriorate. As shown in FIGS. 1 and 4, the lower end of the second bearing 34 is
Since the groove 64 through which the two oils flow is provided, the groove 6
From 4, engine oil flows out of the sensor. Therefore, it has the effect that the engine oil does not accumulate inside the sensor.

Further, as shown in FIGS. 1 and 5, the hexagonal portion 45 is provided at the upper end of the shaft portion 43 provided on the lower surface of the magnet 42, and has the same shape as the hexagonal portion 45. The shaft portion 4 of the magnet 42 has a hole 49.
3 and the first bearing 3 of the cylindrical portion 32.
Since the washer 48 is provided so as to be in sliding contact with the lower surface 3, the shaft 43 and the washer 48 are firmly fixed.
That is, the rotation of the magnet 42 and the shaft 43 does not cause the washer 48 to come off the shaft 43.

In the rotation speed sensor according to one embodiment of the present invention, the first bearing 33 is provided with the first screw groove 37 and the second bearing 3 is provided.
Although the case where the second screw groove 39 is provided in 4 has been described, when the oil seal 81 is provided on the lower surface of the first bearing 33, the screw groove 37 is not provided in the first bearing 33. In this case, the second bearing 34 is
Is prepared, and then the oil seal 81 is inserted into the cylindrical portion 32 from the storage recess 35 side.
Are assembled by press-fitting the bearings 33.

[0026]

As described above, according to the present invention, by providing a portion where a screw groove is formed and a portion where a screw groove is not formed on the outer peripheral surface of the second bearing, the bearing is rotated together with the rotation of the mating shaft and the magnet. Is not loosened, so that it is possible to provide a rotation speed sensor with improved characteristics.

Further, since the housing has an opening surface on the side opposite to the guide, an effect of providing a rotation speed sensor which can easily solder the terminals of the substrate and the connector terminals of the cover can be provided. Also, by providing at least one groove through which the oil flows toward the side surface at the lower end of the second bearing of the cylindrical portion, the engine oil flows out of the sensor through this groove, and the engine oil flows inside the sensor. This has the effect of providing a sensor with improved characteristics that does not accumulate in the sensor.

Further, a hexagonal portion is provided at the upper end of the shaft portion of the magnet, and has a hole having the same shape as the hexagonal portion. By providing the washer that slides on the lower surface, the magnet and the washer are firmly fixed, so that it is possible to provide a rotation speed sensor with improved characteristics in which the washer does not rotate with the rotation of the magnet. It has.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a rotation speed sensor according to an embodiment of the present invention.

FIG. 2 is a sectional side view of the same.

FIG. 3 is a perspective view of a first bearing which is a main part of the same.

FIG. 4 is a perspective view of a second bearing which is a main part of the same.

FIG. 5 is a perspective view of a washer as the main part.

FIG. 6 is a sectional view of a conventional rotation speed sensor.

FIG. 7 is an assembled perspective view showing a fitting state of a magnet and a bearing, which are main parts of a conventional rotation speed sensor.

[Explanation of symbols]

 31 case 32 cylindrical portion 33 first bearing 34 second bearing 35 storage recess 36, 38 unformed portion 37, 39 screw groove 42 magnet 43 shaft portion 45 hexagonal portion 48 washer 49 hole 50 substrate 51 magnetoelectric conversion element 53 terminal 54 cover 55 guide part 56 storage part 57 connector part 58 connector terminal 64 groove

Claims (4)

[Claims] A case having a first bearing at an upper end of a cylindrical portion, a second bearing at a lower end of the cylindrical portion, and a storage recess formed at an upper end of the cylindrical portion; A cylindrical magnet provided on an upper part of the shaft fitted to the first bearing and disposed in the storage recess of the case; and a magnet provided to close an opening of the storage recess of the case. A cover including a guide portion for storing the magnet in a storage recess of a case, a storage portion provided in parallel with the guide portion, and a connector portion having a connector terminal provided above the guide portion and the storage portion. And an electronic circuit board including a magneto-sensitive element fixed to the storage portion of the cover and electrically connected to a connector terminal of the connector portion of the cover, and a screw is provided in the middle of the outer surface of the second bearing. Groove formation location and A rotation speed sensor with a screw groove unformed portion. 2. A case having a first bearing at an upper end of a cylindrical portion, a second bearing at a lower end of the cylindrical portion, and a storage recess formed at an upper end of the cylindrical portion; A cylindrical magnet provided on an upper part of the shaft fitted to the first bearing and disposed in the storage recess of the case; and a magnet provided to close an opening of the storage recess of the case. A cylindrical guide portion for housing the magnet in a storage recess of the case and projecting downward, and a storage portion arranged in parallel with an opening surface on a side opposite to the guide portion, and the guide portion and the storage portion; A cover including a connector portion provided above the portion and having a connector terminal protruding into the storage portion; and a magneto-sensitive device fixed to the storage portion of the cover and electrically connected to the connector terminal of the connector portion of the cover. Electronic device including element A rotational speed sensor including a road substrate and having a portion where a screw groove is formed and a portion where a screw groove is not formed in the middle of the outer surface of the second bearing. 3. The rotation speed sensor according to claim 1, wherein at least one oil circulation groove is provided on a lower end surface of the second bearing from a center outward. 4. A polygonal portion is provided below a magnet forming portion of the shaft portion provided with the magnet, and has a hole having the same shape as the polygonal portion. 3. The rotation speed sensor according to claim 1, further comprising a washer that slides on the bearing.