JP3065496B2 - Electromagnetic rotation detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting a rotation speed or a rotation amount of a rotating body using electromagnetic induction.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open Publication No.
BACKGROUND ART A wheel speed sensor disclosed in JP-A-134569 is known. The wheel speed sensor includes a sensor rotor that rotates in synchronization with a wheel, and a sensor main body as an electromagnetic pickup fixed to the vehicle body and disposed close to serration teeth formed on the sensor rotor. Can magnetically detect the rotation of the sensor rotor.

[0003]

In such a conventional rotation detecting device, since the rotation speed sensor mounting hole of the mounting member is exposed to the atmosphere, the rotation speed sensor mounting hole is made of iron by water or water contained in the air. The sensor mounting holes corrode and promote the generation of rust, and the growth of this rust tightens the main body cylinder of the rotation speed sensor, and the rotation speed sensor and the mounting hole of the mounting member are fixed, which may cause a problem that removal becomes difficult. is there. At this time, if the rotation speed sensor is to be removed from the mounting member, breakage or destruction occurs.

[0004] Japanese Unexamined Patent Publication No. Hei 3-134569 discloses a method in which a sleeve as a separate member is inserted into a mounting hole of a mounting member, and a cylindrical portion of a sensor main body is fitted inside the sleeve. Has reduced intrusion. Further, the degree of progress of natural corrosion is reduced by subjecting the sleeve to galvanization resistant to corrosion. However, this is expensive because it uses a separate member as a sleeve.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electromagnetic rotation detecting device capable of easily removing a mounting member for holding a detecting portion from a mounting member on a vehicle body side. Another object of the present invention is to provide an electromagnetic rotation detection device that can be removed with a small removal force even when rust is generated at an insertion portion between a mounting member on a vehicle body side and a holding member that holds a detection unit. .

Still another object of the present invention is to provide a function of aligning a rotating body and a rotation detecting unit without using a separate member other than a holding member for holding a mounting member and a detecting unit on a vehicle body side, An object of the present invention is to provide an electromagnetic rotation detecting device that can be manufactured lightly and at low cost.

[0007]

[0008]

According to a first aspect of the present invention, there is provided an electromagnetic rotation detecting device which is provided at a position which does not hinder the rotation of a rotating member which rotates in conjunction with the rotation of a wheel. An electromagnetic rotation detection unit that detects the rotation of the rotating body at a position near the cylindrical unit that holds the electromagnetic rotation detection unit, and a support that extends from the cylindrical portion in a direction orthogonal to the cylinder axis. Holding member, having an insertion hole for fixing the support portion and inserting the cylindrical portion through a gap,
A mounting member fixed to the vehicle body, wherein an outer peripheral portion of the cylindrical portion is formed so that an outer diameter decreases from the support portion side end toward the rotating body, and is in contact with the mounting member.
And having a tapered portion that.

[0009]

According to the electromagnetic rotation detecting device of the first aspect, since the holding member for holding the rotation detecting portion is inserted into the insertion hole of the mounting member through the gap, the insertion hole of the mounting member is provided. Even if rust or the like is generated on the inner wall of the housing, a fixing force for tightening the cylindrical portion does not act, so that the holding member can be removed from the mounting member with a small operation force. Therefore, maintenance work can be easily performed.

[0010]

Further, since having the function of maximum outer diameter of the taper portion to perform axial alignment of the insertion hole and the rotation detector, the positioning of the rotation detecting unit and the detected portion of the rotating body side can be reliably performed The rotation speed or the rotation amount can be accurately detected without impairing the output function of the rotation detecting unit.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 show a first embodiment in which the electromagnetic rotation detecting device of the present invention is applied to a device for detecting a wheel speed of an automobile or the like.
Shown in The electromagnetic rotation detecting device 10 has a housing 11 made of a synthetic resin, and its outer periphery is covered. A spool 12 made of a synthetic resin is formed in contact with the housing 11.

The core 13 and the permanent magnet 14 are sealed to the spool 12, and the detection coil 15 is wound around the core 13 via the spool 12. Rotating plate 1 made of magnetic material
6 is a small-diameter portion 1 of the core 13 in which tooth portions 16a and toothless portions 16b are formed alternately and are fixed to the wheel shaft of the automobile.
3e. The core 13 has a columnar shape and each section has a circular cross-sectional shape. The core 13 has one end 13a inserted into and fixed to the permanent magnet 14, and a columnar large-diameter portion 13b having a larger diameter than the end 13a has a shoulder 13c connected to the permanent magnet 1.
4 is in contact with the end face. Subsequent to the large diameter portion 13b, a trapezoidal narrowed portion 13d having a vertical cross-sectional shape whose diameter continuously decreases linearly as it approaches a rotating plate 16 described later is formed. A small diameter portion 13e is formed following the narrowed portion 13. A part of the small diameter portion 13e is exposed to the outside of the housing 11, and forms a certain gap between the small diameter portion 13e and the tooth portion 16a of the rotating plate 16.

The detection coil 15 has a boundary portion 13f between the large diameter portion 13b and the throttle portion 13d.
It is wound around the core 13 via the spool 12 so as to be closer to the permanent magnet 14 side than the winding end 15a on the side.
The winding 17 of the detection coil 15 is held by the locking portion 20 and wound around and connected to the winding portion 21 a of the terminal 21. The lead wire 22 is connected to the terminal 21 and is drawn out of the housing 11.

In the housing 11, the stay 24 is integrally formed by insert molding. At the base of the tubular portion 11a of the housing 11 with the stay 24, a tapered portion 26 forms an annular slope such that the outer diameter gradually decreases from the stay end surface 24a toward the tip of the tubular portion 11a. . As shown in FIG. 1, the tapered portion 26 has a structure to be inserted into a cylindrical hole 25a formed in the mounting member 25, and is provided between the inner peripheral wall of the cylindrical hole 25a and the outer peripheral wall of the cylindrical portion 11a. A gap is formed. The tapered portion 26 has an action of centering the cylindrical portion 11a such that the center of the annular root end of the tapered portion 26 coincides with the center of the cylindrical hole 25a of the mounting member 25. 11 can be simultaneously fixed and adjusted in position.

The tapered portion 26 has an inclination angle θ as shown in FIG. If the value of θ is too small, the centering action is improved, but as shown in FIG. 3A, the taper portion 26 approaches the cylindrical shape, and the cylindrical portion 11
a, the annular gap distance δ from the cylindrical hole 25a is apparently reduced, and the tapered portion is tightened due to the progress of rust in the cylindrical hole 25a, thereby reducing the effect of reducing the detaching force. If the value of θ is too large, the alignment effect is reduced as shown in FIG. 3 (B), the annular gap distance δ between the cylindrical hole 25a and the cylindrical portion 11a becomes excessive, and the mounting member 25 is locally The thickness of the mounting member 25 is undesirably reduced because the thickness of the mounting member 25 is reduced. Therefore, the inclination angle θ is set to a value in a satisfying range satisfying the above purpose. The provision of the inclination angle θ of the tapered portion 26 does not increase the required removal force for removing the electromagnetic rotation detecting device 10 from the mounting member 25, and thus does not dynamically hinder the removal operation. There are advantages.

At the time of assembling, the cylindrical part 11a as a molded product in which the housing 11 and the stay 24 are integrally formed of resin is inserted into the cylindrical hole 25a of the mounting member 25, and the bolt 31 is tightened. The stay 24 is fixed, and the housing 11 of the electromagnetic rotation detecting device 10 is fixed to the mounting member 25. Note that the holding member in the claims corresponds to the housing 11 and the stay 24, and the axial direction of the holding member corresponds to the vertical direction in FIGS.

Next, the operation of the electromagnetic rotation detecting device 10 will be described. The magnetic flux generated by the permanent magnet 14 passes through the large diameter portion 13b and enters the throttle portion 13d. Since the diameter of the constricted portion 13d continuously decreases linearly as it approaches the rotating plate 16, the magnetic flux is gradually converged while passing through the constricted portion 13d and concentrated on the small-diameter portion 13e, so that the magnetic flux density is high. Become.
The magnetic flux concentrated on the small diameter portion 13e is transmitted to the rotating plate 16.
When the rotating plate 16 rotates, the tooth portions 16a and the missing tooth portions 16b alternately pass through the end surface of the small diameter portion 13e, and the gap between the end surface of the small diameter portion 13e and the rotating plate 16 changes. When the magnetic flux transmitted from the small diameter portion 13e to the rotating plate 16 changes with the change in the gap, an induced electromotive force is generated in the detection coil 15 in accordance with the rate of change of the magnetic flux. The generated induced electromotive force is
7, through the terminal 21 and the lead wire 22, it is taken out of the device as the output voltage of the detection device. The output voltage taken out of the apparatus is input to a control unit (not shown), and the rotation speed or amount of rotation of the rotating plate 16 is detected based on the amplitude and frequency of the output voltage, and the vehicle speed is calculated.

According to the above embodiment, as shown in FIG.
Since an annular gap is formed between the inner peripheral wall of the cylindrical hole 25a of the mounting member 25 and the outer peripheral wall of the cylindrical portion 11a, the end surface 24a of the stay 24 contacts the end surface 25b of the mounting member 25, and the bolt 31 is When tightened, the annular root of the tapered portion 26 fits into the cylindrical hole 25a and
And the center line of the cylindrical portion 11a is aligned. The centering effect is great because the tapered portion 26a is formed annularly mechanically. Accordingly, the shaft center can be simultaneously adjusted when the bolt 31 is tightened and fixed, so that the tooth portion 16a of the rotating plate 16 and the electromagnetic rotation detecting device 10
There is an effect that the positioning with the small-diameter portion 13e is more accurately performed.

Further, according to the present embodiment, an appropriate annular gap is formed between the inner peripheral wall of the cylindrical hole 25a of the mounting member 25 and the outer peripheral wall of the cylindrical portion 11a of the housing 11, so that it can be used during use. Even if rust is generated on the inner peripheral wall surface of the cylindrical hole 25a, there is an effect that when the electromagnetic rotation detecting device 10 is detached from the mounting member 25, the detachment can be easily performed because of the space. That is, since there is an annular gap of a certain size between the inner peripheral wall of the cylindrical hole 25a and the outer peripheral wall of the cylindrical portion 11a, even if rust is generated, the fixing action of the rust is relatively weak. In addition, the housing 11 can be easily removed from the mounting member 25 at the time of removal.

Next, experimental data will be shown. In the experiment, the relationship between the growth of rust formed on the inner peripheral wall of the cylindrical hole 25a of the mounting member 25 and the thickness of the rust was measured. As shown in FIG. 4, the thickness of the rust formed in the gap δ between the cylindrical portion 11a and the cylindrical hole 25a grows as time passes, as shown in FIG. The growth example of the rust thickness h shown in FIG. 5 is one experimental example. As can be understood from FIG. 5, at the initial stage, the rust generation rate is slow, but gradually thereafter, the rust growth rate increases with time, and after a certain period of time, the rust growth stops and the rust thickness h is reduced. Stabilize. Thus, if the size of the gap δ between the inner peripheral wall of the cylindrical hole 25a and the outer peripheral wall of the cylindrical portion 11a is a relatively large value, there is an effect that the housing can be removed with a small operating force. found. Also, if a certain amount of time has passed,
Since the thickness h of the rust converges to a constant value, even if there is a gap larger than a predetermined value, the effect of reducing the removing operation force does not work. Thus, the inner peripheral wall of the cylindrical hole 25a and the housing 11
It has been found that the operation of removing the cylindrical portion 11a from the mounting member 25 becomes easy if the size of the gap δ with the outer peripheral wall of the cylindrical portion 11a is equal to or larger than a predetermined value.

Next, the embodiment of the present invention and another comparative example will be compared. Comparative examples were a first comparative example shown in FIG. 6 and a second comparative example shown in FIG. In the first comparative example shown in FIG. 6, the protrusions 41, 42, and 4 are provided at the root of the tubular portion 11a to the stay 24.
This is an example in which 3, 44 are formed at 90 ° intervals in the circumferential direction. In this example, when the electromagnetic rotation detecting device 10 is inserted into the cylindrical hole 25a of the mounting member 25 and tightened and fixed with bolts, FIG.
As shown in (B), since the projections 41, 42, 43, and 44 are tightly joined to the inner wall of the cylindrical hole 25a of the mounting member 25, when rust is generated on the inner peripheral wall of the cylindrical hole 25a, the protrusion is formed. The parts 41, 42, 43, and 44 are in close contact with the cylindrical hole 25a,
This close contact portion firmly fixes the rust and makes it difficult to remove the tubular portion 11a from the mounting member 25.

The second comparative example shown in FIG. 7 is an example in which a large-diameter annular portion 51 is formed at the base of the tubular portion 11a with the stay 24. The large-diameter annular portion 51 is inserted into the cylindrical hole 25a of the mounting member 25. In this case, since the outer peripheral portion of the large-diameter annular portion 51 is in close contact with the inner wall of the cylindrical hole 25a,
When the rust occurs, the cylindrical hole 25a and the large-diameter annular portion 51 are fixed to each other by the rust. Therefore, when the electromagnetic rotary device 10 is removed from the mounting member 25, it is difficult to remove the electromagnetic rotating device 10 from the fixed portion. For this reason, also in the second comparative example, the detachability is reduced.

In comparison with the first comparative example shown in FIG. 6 and the second comparative example shown in FIG. 7, according to the present embodiment, the housing 11 is inserted into the cylindrical hole 25a of the mounting member 25, and the bolt 32 is tightened. When fixed, an annular cylindrical gap is formed in the outer peripheral portion of the housing 11, and this gap prevents rust from being fixed. Therefore, the housing 11 can be easily removed from the mounting member 25. In addition, since the tapered portion 26 performs centering of the cylindrical hole 25a and the rotation detecting device main body at the time of mounting, the position of the detecting portion of the detecting device and the detected portion can be easily adjusted.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state of attachment to an attachment member according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a rotation detection device main body according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing an inclination angle of a tapered portion according to the embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view showing a thickness of rust formed in an insertion hole of a mounting member.

FIG. 5 is a characteristic diagram showing a growth state of rust thickness.

6A and 6B show a first comparative example, in which FIG. 6A is a side view of the electromagnetic rotation detection device main body, and FIG. 6B is a cross-sectional view showing a state where the electromagnetic rotation detection device main body is attached to a mounting member. It is.

FIG. 7 is a side view of an electromagnetic rotation detection device according to a second comparative example.

[Explanation of symbols]

 Reference Signs List 10 electromagnetic rotation detecting device 11 housing (holding member) 11a cylindrical portion (holding member) 13e small diameter portion (electromagnetic rotation detecting portion) 16 rotating plate (rotating body) 16a tooth portion 24 stay (supporting portion, holding member) 25 Mounting member 25a Insertion hole 26 Tapered part 31 Bolt

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Ryuji Takasu 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (56) References JP-A-5-141910 (JP, A) JP-A-7-280822 (JP, A) JP-A-7-191048 (JP, A) JP-A-1-15664 (JP, U) JP-A-7-32569 (JP, U) (58) Fields investigated (Int. Cl. ⁷⁾ G01P 3/488 G01D 5/245

Claims (1)

(57) [Claims] 1. A rotating body that rotates in conjunction with the rotation of a wheel, and an electromagnetic rotation detector that is provided at a position that does not hinder the rotation of the rotating body and detects the rotation of the rotating body at a position near the rotating body. A cylindrical member for holding the electromagnetic rotation detecting unit, and a holding member having a support extending from the cylindrical part in a direction orthogonal to the cylindrical axis; and fixing the support to the cylindrical part. A mounting member fixed to the vehicle body side, and an outer peripheral portion of the cylindrical portion is outwardly directed from the support portion side end toward the rotating body side. diameter is formed so smaller preparative said
An electromagnetic rotation detection device having a tapered portion that comes into contact with an attachment member .