JPH0816681B2 - Revolution sensor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation speed sensor using electromagnetic means equipped with a rotating disk-shaped multi-pole magnet used for detecting vehicle speed of an automobile.

2. Description of the Related Art Conventionally, this type of rotation speed sensor has a structure as shown in FIG. That is, the rotating disc-shaped multipole magnet 11
Is integrally formed with the main shaft 13 using a synthetic resin 12. The main shaft 13 has a housing hole at its end, in which a coil spring is
14 is mounted on the bearings 15a and 15b in a set state. When the tack 16 is pressed against the plate 17 by the coil spring 14, rattling in the axial direction of the magnet 11 that is integral with the main shaft 13 is regulated, and malfunction due to vibration is prevented by frictional resistance. The main shaft 13 of the sensor is connected to the rotating body to be measured by a joint shaft 19 fitted in the deformed hole 18 of the main shaft 13. The life of such a conventional speed sensor is stud
Depends on the wear resistance properties of 16 and plate 17. Also, the main axis of the sensor
The misalignment between 13 and the shaft of the rotating body to be measured is absorbed by the fitting degree of the joint shaft 19. In the figure, 20 is a magnetic detection circuit, and 21a and 21b are an upper case and a lower case.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above-mentioned configuration, since the multipole magnet 11, the molding resin 12, and the main shaft 13 have large thermal expansion coefficients, in the use in a wide temperature range of an automobile or the like, the molding resin 12 or,
A crack may occur in the multi-pole magnet 11, and the joint shaft 19 is missing during assembly and mounting, which is troublesome for work. Further, there is a problem that an inexpensive rotation speed sensor cannot be supplied because the structure is complicated.

The present invention solves such a conventional problem, and an object thereof is to provide an excellent rotation speed sensor which can be used in a wide temperature range and can be easily assembled and attached at low cost.

Means for Solving the Problems In order to solve the above problems, the present invention directly inserts a main shaft into a disc-shaped multi-pole magnet, and further inserts a connecting shaft into the main shaft, and at least one of the E The structure is such that the shape ring is fitted to prevent it from coming off and a leaf spring is attached so that the rotary shaft to which the multi-pole magnet is attached is held by the elastic force of the leaf spring.

Action The present invention eliminates materials having large thermal expansion coefficients due to the above-mentioned configuration, so that the reliability of fixing the multi-pole magnet in a wide temperature range is improved and the leaf spring and the E-shaped ring are used to prevent slipping. Since the joint shaft is directly attached to the bearing portion, it is possible to prevent the joint shaft from missing and to improve the efficiency of the assembling work.

Embodiment Hereinafter, a rotation speed sensor according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a rotation speed sensor of the present invention. First
In the figure, reference numeral 1 denotes a disc-shaped multi-pole magnet magnetized on the circumference of a circle. As shown in FIG. 2, a spindle 2 is provided in a center-shaped irregular hole 1a of the disc-shaped multi-pole magnet 1. , The polygonal hole 2a in the center of the spindle 2
The joint shaft 3 is fitted so as to be slidable in the axial direction and rotate in the same direction. Further, the joint shaft 3 is prevented from coming off by the first and second E-shaped rings 4a and 4b, and is pressed against the bearing 6 by the leaf spring 5. The spindle 2 to which the disc-shaped multi-pole magnet 1 is attached is elastically held by a leaf spring 5. Note that 7a and 7b are both washers, 8a and 8b are upper and lower cases, and 9 is a magnetic detection circuit.

During operation of this sensor, the main shaft 2 and the disc-shaped multi-pole magnet 1 are pressed against the bearing 6 by the leaf spring 5, and the joint shaft 3 rotates while the vibration malfunction is prevented by the friction torque between them. As a result, the magnet 1 magnetized by the circumferential multipole is rotated, and the magnetic detection circuit 9 generates a detection pulse according to the rotation.

As described above, according to the above-described embodiment, the rotary sliding surface has the bearing 6
Since both ends of the joint shaft 3 are not required, a complicated structure for achieving a long life is not required, and the joint shaft 3 is not missing and the assembly is easy.

Further, the main shaft 2 is directly fixed to the magnet 1 by fitting with a proper clearance and the leaf spring 5 without interposing a material such as a synthetic resin having a large coefficient of thermal expansion differently in the middle. It is extremely unlikely to be affected by stress due to the difference in coefficient of thermal expansion of materials.

Effects of the Invention The present invention has the following effects, as is apparent from the above embodiment.

(1) Since the disc-shaped multi-pole magnet and the main shaft are fixed by fitting with a clearance and fixing by a leaf spring, the reliability in a wide temperature range is high.

(2) Since the joint shaft has an E-shaped ring to prevent it from coming off, assembly is easy.

(3) Since the sliding surfaces are at both ends of the bearing, the structure is simple and an inexpensive rotation speed sensor can be supplied.

[Brief description of drawings]

FIG. 1 is a sectional view of a rotation speed sensor in one embodiment of the present invention, FIG. 2 is a sectional view of a fitting portion of a magnet, a main shaft, and a joint shaft in the sensor, and FIG. 3 is a cross section of a conventional rotation speed sensor. FIG. 4 and FIG. 4 are cross-sectional views of the fitting portion of the joint shaft and the main shaft of the sensor. 1 ... Disc-shaped multi-pole magnet, 1a ... Deformed hole, 2 ... Spindle, 3
…… Joint shafts, 4a, 4b …… E-shaped rings, 5 …… Leaf springs, 6…
… Bearings, 8a, 8b …… Case, 9 …… Magnetic detection circuit.

Claims (1)

[Claims] 1. A disk-shaped multi-pole magnet connected to a rotating body to be measured through a joint shaft and a main shaft and a magnetic detection circuit are housed in a case, and the rotation speed of the multi-pole magnet is changed to the magnetic detection circuit. A rotation speed sensor for detecting the rotation speed of a rotating body to be measured by detecting by means of: a first and a second E-shaped ring for preventing the slip-off from being provided on the joint shaft in the case.
Having the main shaft between the E-shaped rings, and fixing the main shaft and the bearing by the first E-shaped ring and the leaf spring,
A rotation speed sensor in which the main shaft is inserted into the bearing fixed to the case and is fitted and fixed through a deformed hole at the center of the multipolar magnet so as to be slidable in the axial direction.