JPH07325093A - Rotation speed detection device - Google Patents

Abstract

PURPOSE:To provide the rotation speed detection device which can be inserted into an installation hole even if the length of the bent section of a pole piece provided at the tip end of a housing is larger than the radius of the housing. CONSTITUTION:A gap is so designed as to be available when the tip end of a housing 5 is inserted into an installation hole 6 by forming a bent pole piece 8 into a multi-step structure which has the housing 5 made smaller in diameter toward the tip end, which is installed at the tip end. It is so designed that the pole piece 8 the bent section of which is made longer than the radius of the housing 5, can be inserted into the installation hole 6 by trying to insert the housing 5 with the housing tilted by making use of the gap, or by making it possible to insert the housing 5 with the housing rotated after the tip end of the bent section of the pole piece 8 has been inserted into the installation hole.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation speed detecting device for detecting the rotation speed of a wheel or a crankshaft of an engine.

[0002]

2. Description of the Related Art An electromagnetic rotation speed detecting device shown in FIG. 7 is known as a rotation speed detecting sensor for an automobile which is required to be robust, less susceptible to aging and highly reliable.

This rotation speed detecting device is provided with a sensor rotor 1
And the sensor body 2 and the sensor rotor 1
Is provided with serrations 3 on its outer periphery and is attached to an axle or a crankshaft.

On the other hand, the sensor main body 2 accommodates a pickup coil wound around a bobbin and a magnet joined in series with the pickup coil in a cylindrical housing 5 attached to the base 4, for example, a steering knuckle or a steering knuckle. The sensor is mounted in the housing of the transmission so as to face the sensor rotor 1, and the pickup coil detects that the magnetic flux generated from the magnet of the sensor body 2 changes due to the rotation of the sensor rotor 1, and determines the amount of change in the rotation of the sensor rotor 1. Outputs the corresponding AC voltage.

By the way, the sensor body 2 is provided with a mounting hole 6 in a steering knuckle, a housing of a transmission, or the like, as shown in FIG.
The flange 7 provided on the housing 5 is joined to the mounting hole 6 to be mounted. However, in a steering knuckle, a housing of a transmission, or the like, the end surface of the housing 5 is narrow so as to directly face the serration 3 of the sensor rotor 1. It may not be possible. In that case, as shown in FIG. 6, a kind of magnetism collecting steel called a pole piece 8 is attached to the front end surface of the housing 5, and the pole piece 8 is attached by bending.

[0006]

However, in the rotation speed detecting device provided with the above-mentioned pole piece, the mounting hole of the sensor body must be kept away from the sensor rotor due to the restrictions on the vehicle body side, and the diameter of the sensor rotor must be reduced. If you cannot make it larger, the bent part of the pole piece becomes longer, and if the bent part of the elongated pole piece becomes longer than the housing radius, the mounting hole is almost the same as the housing diameter or slightly larger. Therefore, there is a problem that the pole piece cannot be inserted while being supported by the mounting hole (the design needs to be changed to make the mounting hole larger).

Therefore, an object of the present invention is to provide a rotation speed detecting device which can be inserted into a mounting hole even when the pole piece becomes long.

[0008]

In order to solve the above-mentioned problems, according to the present invention, a bent pole piece is attached to the tip of a housing that houses a pickup coil and a magnet and is fitted into an attachment hole. In a rotation speed detecting device in which the front end surface of the pole piece is opposed to the sensor rotor and the rotation of the sensor rotor is detected from the change in the magnetic flux passing through the pickup coil, the front end of the housing has a smaller diameter than the rear end. Was adopted.

At this time, it is possible to employ a multi-step structure in which the housing is gradually reduced in diameter toward the tip.

Further, the housing has a taper shape with a small diameter toward the tip, and the housing has a multi-step structure with a step having a diameter gradually decreasing toward the tip of the housing, and a taper shape with a small diameter toward the tip. It is also possible to adopt a composite structure in which and are combined.

[0011]

In the rotational speed detecting device constructed as described above, since the front end diameter of the housing is formed smaller than the rear end diameter, the mounting hole of the housing is equal to or slightly larger than the rear end diameter of the housing. It will be formed in the diameter.
Therefore, when the tip of the housing is inserted into the mounting hole, a gap is formed between the tip diameter of the housing and the mounting hole.

Therefore, utilizing the gap, for example,
Slide the sensor body laterally to the mounting hole, insert it at an angle, or insert the tip of the bent part of the pole piece into the mounting hole and then insert it while rotating the housing. For example, a pole piece longer than the radius of the housing can be inserted.

Further, in the multi-stage structure in which the housing has a stepwise small diameter toward the tip, the above-mentioned invention is achieved by forming the housing to have a tip diameter smaller than a rear end diameter. It also allows the insertion of pole pieces longer than the radius of the housing.

In the case where the housing is tapered, the front end diameter of the housing is made smaller than the rear end diameter by making the housing tapered, so that a pole piece longer than the radius of the housing is inserted as in the above invention. To be able to.

In the composite structure in which the housing has a multi-step structure in which a step is made gradually smaller toward the front end of the housing and has a taper shape, the front end diameter of the housing is smaller than the rear end diameter by the composite structure. The small diameter allows the pole piece longer than the radius of the housing to be inserted, as in the above invention.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. At this time, the parts described in the conventional example are designated by the same reference numerals in the drawings, and the description thereof will be omitted.

FIG. 1 shows a first embodiment of the rotation speed detecting device.

In the rotational speed detecting device of this embodiment, the housing 5 of the sensor body 2 is formed in a two-step structure consisting of a large diameter portion 9 at the rear end and a small diameter portion 10 at the tip, and the housing 5 has a tip at the tip thereof. The bent pole piece 8 is attached.

The large-diameter portion 9 at the rear end is formed to have a diameter slightly smaller than that of the mounting hole 6 so that it can be fitted into the mounting hole 6.

The dimension A from the central axis of the housing 5 to the bent tip of the pole piece 8 is determined by the housing 5
It is larger than the radius B of the large diameter portion 9 at the rear end.

This embodiment is constructed as described above. Next, a method of mounting the sensor body 2 in the mounting hole 6 will be described.

The sensor body 2 is attached depending on whether the pole piece 8 protruding from the large diameter portion 9 at the rear end of the housing 5 has a short dimension (B ≧ A) or a long dimension (B << A).
Can be inserted into the mounting hole 6 by, for example, the following methods.

When the size of the pole piece 8 protruding from the large diameter portion 9 at the rear end of the housing 5 is short (B ≧ A), the sensor main body 2 is slid laterally with respect to the mounting hole 6 so as to be mounted. A space is formed between the housing 6 and the hole 6, and the space is used to insert the sensor body 2. Alternatively, as shown in FIG. The pole piece 8 is inserted by utilizing the gap formed between the small diameter portion 10 at the tip and the mounting hole 6. Then, the sensor body 2 is rotated vertically to the mounting hole 6, and the large diameter portion 9 at the rear end of the housing 5 is inserted into the mounting hole 6 as shown in FIG. It is joined to the periphery of the mounting hole 6 and mounted in a regular position.

When the pole piece 8 protruding from the large diameter portion 9 at the rear end of the housing 5 has a long dimension (A >> B), the sensor body 2 is slanted as shown in FIG. 3 (a). Then, the tip of the bent pole piece 8 is inserted into the mounting hole 6. Next, as shown in FIG. 3B, the sensor body 2 is rotated to insert the bent portion of the pole piece 8 into the mounting hole 6, and then the housing 5 is made perpendicular to the mounting hole 6. Then, as shown in FIG. 3C, the housing 5 is inserted into the mounting hole 6, the flange 7 is joined to the periphery of the mounting hole 6, and the housing 7 is mounted in the regular position.

Thus, by making the diameter of the tip of the housing 5 small, the gap formed between the housing 5 and the mounting hole 6 is utilized, and even if the dimension of the bent portion of the pole piece 8 becomes long, the sensor The body 2 can be mounted in the mounting hole 6.

FIG. 4 shows a second embodiment of the rotation speed detecting device.

In this case, the housing 5 is formed in a tapered shape 11 so that the front end diameter of the housing 5 is smaller than the rear end diameter.

The other parts and their functions are the same as those in the first embodiment, and therefore the description thereof is omitted here.

FIG. 5 shows a third embodiment of the rotation speed detecting device.

In this structure, the rear end of the housing 5 has a large diameter portion 9, while the tip has a small diameter portion 10 and a taper portion 11 is provided between them, whereby the housing 5 has a multi-step structure and a taper shape 11. Of the composite structure, and the front end diameter is formed smaller than the rear end diameter by using the composite structure.

In this case as well, as in the second embodiment, the other parts and their functions are the same as in the first embodiment.
The description is omitted here.

[0032]

[Effects] The present invention is configured as described above, and the outer shape of the housing is, for example, a multi-step structure, a taper shape, or a composite structure of a multi-step structure and a taper shape. In the field of detecting the rotation speed of wheels and engine crankshafts, the distance between the mounting hole of the detection device and the sensor rotor is greatly separated, and the dimension up to the bent tip of the pole piece is the radius of the housing. It is possible to provide a rotation detection device that can be inserted without enlarging the mounting hole even if the length is longer than that. Therefore, it is possible to cope with the mounting hole without increasing the diameter due to the design change, and it is possible to prevent the cost increase due to the design change.

[Brief description of drawings]

FIG. 1 is a front view of the first embodiment.

FIG. 2 is an operation explanatory view for explaining the mounting method of the first embodiment.

FIG. 3 is an operation explanatory view for explaining a mounting method of the first embodiment.

FIG. 4 is a front view of the second embodiment.

FIG. 5 is a front view of the third embodiment.

FIG. 6 is an operation explanatory view illustrating a conventional rotation speed detection device.

FIG. 7 is an operation explanatory view for explaining a conventional rotation speed detection device.

[Explanation of reference symbols] 1 sensor rotor 2 sensor body 3 serration 4 base 5 housing 6 mounting hole 7 flange 8 pole piece 9 large diameter portion at rear end 10 small diameter portion at tip 11 taper shape

Claims (4)

[Claims] 1. A sensor rotor having a pickup coil and a magnet housed therein, wherein a bent pole piece is attached to a tip of a housing fitted in an attachment hole, and a tip surface of the pole piece is opposed to the sensor rotor. In the rotational speed detecting device for detecting the rotation of the housing from the change in the magnetic flux passing through the pickup coil, the rotational speed detecting device in which the front end portion of the housing has a smaller diameter than the rear end portion. 2. The multi-step structure in which the housing has a stepwise small diameter toward the tip thereof.
The rotation speed detection device described in. 3. The rotation speed detecting device according to claim 1, wherein the housing has a taper shape having a small diameter toward the tip. 4. The composite structure, wherein the housing is formed by combining a multi-step structure in which the diameter is gradually reduced toward the tip of the housing and a tapered shape in which the diameter is reduced toward the tip. The rotational speed detection device described.