JPS62163970A - Rotational speed detector - Google Patents

Abstract

PURPOSE:To make it possible to easily mount the titled detector in a compact shape, by forming a conductive casing from first and second internal mount parts integrally in coaxial relation to each other and internally mounting a rod-shaped core and a ring shaped core in the first internal mount part coaxially and internally mounting an electronic circuit in the second internal mount part. CONSTITUTION:A detector is assembled by a method wherein an adhesive 36 is applied to the outer peripheral surface of the detection terminal part 32a of a rod shaped core 32 and not only the rod shaped core 31 is inserted in the cylindrical receiving part 31a of a casing 31 but also the detection terminal part 32a of the rod shaped core 32 is inserted in a ring shape opening part 31a under pressure and a spool 33 having an annular coil 34 wound therearound is inserted in the cylindrical receiving part 31A while being engaged with the rod shaped core 32 and a permanent magnet 35 is inserted in the flange 33a of the spool 33 to be mounted to the upper end part of the rod shaped core 32. Subsequently, the conductors 34a, 34b of the annular coil 34 are received in the grooves 38b, 38c of a synthetic resin body 38 to be connected to the connection terminals 37a, 37b of a wave-form shaping circuit 37 and a substrate 38a is placed on the permanent magnet 35 and the synthetic resin body 38 is received in a box shaped receiving part 31B.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotational speed detector employed in a vehicle transmission, and more particularly to a rotational speed detector equipped with an electromagnetic pickup.

[Prior art]

Conventionally, a detector similar to this type of rotational speed detector detects the rotational speed of a rotary plate that is linked to the crankshaft of an internal combustion engine, as disclosed in Japanese Patent Application Laid-Open No. 112205/1983. A photoelectric pickup to be detected and an electronic circuit connected to the photoelectric pickup are housed in a synthetic resin case, and the synthetic resin case is housed in a distributor, and a ceramic substrate of the electronic circuit and a peripheral wall of the synthetic resin case are housed. Some devices have a conductive member placed between them and grounded.

[Problem that the invention seeks to solve]

However, even if such a poultry extractor is installed in a transmission, the photoelectric pickup and the electronic circuit are located far apart from each other, so the external dimensions are too large, and the installation space is severely limited. The problem with the housing is that it is difficult to install.

Furthermore, even if this kind of installation were possible, if the lubricating oil present in the transmission scatters and adheres to the light receiving and emitting parts of the photoelectric pickup, or if it enters between the light receiving and emitting parts of the photoelectric pickup, the photoelectric pickup may become damaged. There is a problem that an error occurs in the optical detection result of the pickup.

Another problem is that when the temperature inside the transmission becomes high, the temperature resistance of the photoelectric pickup becomes insufficient. Furthermore, there is a problem in that the above-mentioned conductive member is required to block high-frequency noise caused by electromagnetic waves from entering the electronic circuit.

Therefore, in order to solve the various problems mentioned above, the present invention attempts to provide a rotational speed detector equipped with an electronic circuit that effectively utilizes the outer shape of the rod-shaped core in the electromagnetic big amplifier. It is something.

[Means for solving problems]

In solving this problem, the structural features of the present invention are as follows:
a plurality of magnetic teeth arranged along the circumferential direction of the rotating shaft supported in the housing of the transmission;
A rod-shaped core inserted through an opening protruding from the peripheral wall of the housing and having an inner end facing any of the plurality of magnetic teeth, an annular coil wound around the rod-shaped core, and a ring-shaped coil wound around the rod-shaped core; In a rotational speed detector comprising an electromagnetic pickup having a permanent magnet provided at an outer end thereof, an electronic circuit connected to the annular coil and an opening of the housing facing any one of the plurality of magnetic teeth. A cylindrical first built-in part that is fitted into the housing and contains the rod-shaped core, the annular coil, and the permanent magnet, and a cylindrical first built-in part that extends coaxially outward from the outer end of the first built-in part and contains the electronic circuit. The present invention is characterized in that the electromagnetic pickup is provided with a conductive casing having a second built-in portion.

[Effect]

By configuring the present invention in this way, the conductive casing can be formed into first and second built-in parts coaxially and integrally formed with each other by effectively utilizing the shape and dimensions of the rod-shaped core. The rod-shaped core and the annular coil are intermittently built into the first built-in part, and the electronic circuit is built into the second built-in part, so that the mounting space within the transmission housing is saved. The electromagnetic pick amplifier can be easily installed even in a narrow place because of its compact shape with the electronic circuit integrated therein. Furthermore, as described above, since the electronic circuit and the annular coil are built into the conductive casing, the intrusion of high frequency noise caused by electromagnetic waves into the electronic circuit and the annular coil is blocked by the conductive casing itself. , there is no need to provide any other structural members necessary for blocking high frequency noise.

Furthermore, since the electromagnetic pickup utilizes changes in magnetic energy, it is possible to accurately detect rotational speed without being affected by lubricating oil. Furthermore, since each component of the electromagnetic pickup is made of a material with good temperature resistance, it can always operate properly regardless of the high temperature inside the transmission. In this case, since the electronic circuit is located outside the transmission housing, it is not directly affected by the high temperature inside the transmission.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.
The figure shows the rotational speed detector according to the present invention installed in a vehicle transmission 10 in a down position, and this rotational speed detector is composed of a gear 20 made of a magnetic material and an electromagnetic pickup 30. There is. The gear 20 is an output shaft rotatably supported within the output side housing 11 of the transmission 10 at its annular boss 21! th1
2, and a plurality of teeth 22 to 22 are formed on the outer circumferential surface of the boss 21 along the circumferential direction thereof at intervals.

The electromagnetic pickup 30 has a casing 31 injection-molded from an aluminum material, and this casing 31 has a cylindrical housing portion 3 as shown in FIGS. 1 and 2.
1A, and a box-shaped accommodating portion 31 that integrally extends upward from the illustrated upper end of the accommodating portion 31A coaxially with the accommodating portion 31A.
It is composed of B. The upper end of the accommodating portion 31A is fitted into an opening 11a formed in the peripheral wall of the output housing 11 directly above the gear 20 through an O-ring 13. An annular opening 31a formed to protrude outward in the axial direction from the center of the bottom wall is connected to the gear 2.
0 and facing one of the teeth 22 of 0. In such case,
The bottom wall of the accommodating portion 31A and the annular opening 31a are uniformly thin enough to maintain appropriate mechanical strength.

A rod-shaped core 32, a spool 33, an annular coil 34, and a permanent magnet 35 are housed in the housing part 31A.The rod-shaped core 32 is located on the central axis of the housing part 31A, and the detection end 32a of the rod-shaped core 32 is located on the central axis of the housing part 31A. is press-fitted into the annular opening 31a via an oil-resistant anaerobic adhesive 36 (for example, Loctite 648) coated on the inner peripheral surface of the annular opening 31a to form a predetermined gap in one of the teeth 22 of the gear 20. directly facing each other.

The spool 33 is made of a synthetic resin material and is fitted into the rod-shaped core 32 at its center.
An annular coil 34 is wound within the annular hollow portion.

The permanent magnet 35 is located at the upper end of the rod-shaped core 3 in FIG. 2 and is held within the flange 33a of the spool 33.
A magnetic circuit is formed together with one of the teeth 22 of 0. This means that the annular coil 34 detects changes in the magnetic flux in the magnetic circuit as the rotational speed of the output shaft 12 and generates an alternating current signal.

A synthetic resin body 38 containing a waveform shaping circuit 37 is housed in the box-shaped housing portion 31B of the casing 30, and is placed on a permanent magnet 35 via a substrate 38a. The high frequency filter 39 is placed in the housing part 31.
It is assembled in B. The waveform shaping circuit 37
As shown in FIG. It is connected to each conducting wire 34a, 34b extending from the annular core 34 through the valley grooves 38b, 38C.

Thus, the waveform shaping circuit 37 receives an AC signal from the annular coil 34 via both conductive wires 34a, 34b and both connecting terminals 37a, 37b, and shapes the waveform thereof.

As shown in FIGS. 2 and 3, the high frequency filter 39 includes a support plate 39a having a U-shaped cross section and a plurality of feedthrough capacitors 39b to 39d. It is fixed to the casing 31 and grounded to the transmission 10 via the casing 31.

Each feedthrough capacitor 39b to 39d is fitted to each arm of the support plate 39a, and these feedthrough capacitors 3
One end of each of 9b to 39d is connected to each connection terminal 37c, 37d, and 37e of the waveform shaping circuit 37, respectively. Further, the other ends of the feedthrough capacitors 39b to 39d are respectively connected to the external conductive wires 11 to β3, and the external conductive wires 11 to 13 extend outward through the peripheral wall of the accommodating portion 31B. Note that the opening of the housing portion 31B is closed by a lid body 31C made of an iron plate. Further, the casing 31 has support arms 31b extending from the outer wall of the container 31B.
It is supported by the female threaded portion 11b of the housing 11 by tightening a bolt 11C (see FIGS. 1 and 3).

Therefore, in this embodiment configured as described above, when assembling the electromagnetic pickup 30, adhesive 36 is applied to the outer peripheral surface of the detection end 32a of the rod-shaped core 32, and the rod-shaped core 32 is housed in the cylindrical shape of the casing 31. 31A, the detection end 32a of the rod-shaped core 32 is press-fitted into the annular opening 31a, and the spool 33 around which the annular coil 34 is wound is fitted into the rod-shaped core 32 while the cylindrical housing portion 31 is inserted.
A, and the permanent magnet 35 is inserted into the flange 33a of the spool 33 and placed on the upper end of the rod-shaped core 32.

Next, the conductive wires 34a and 34b of the annular coil 34 are placed in the grooves 38b and 38c of the synthetic resin body 38, and connected to the connection terminals 37a and 37b of the waveform shaping circuit 37.
a is placed on the permanent magnet 35, and the synthetic resin body 38 is housed in the box-shaped housing part 31B. Furthermore, a high frequency filter 39
is placed on the top surface of the synthetic resin body 38 at the bottom wall of the support plate 39a, and each external conductor! ! 1 to 7!3 are introduced into the box-shaped housing part 31B through its peripheral wall, and each feedthrough capacitor 39b to 3 is
Both ends of 9e are connected to each connection terminal 37c to 3 of the waveform shaping circuit 37.
7e and each external conductor zi to β3 as described above,
After fixing both arms of the support plate 39a to the casing 31,
The opening of the box-shaped accommodating portion 31B is closed by the lid 31C.

As described above, by effectively utilizing the external dimensions of the rod-shaped core 32, the casing 31 is configured by coaxially arranging the cylindrical housing portion 31A and the box-shaped housing portion 31B, and the rod-shaped core 32
, the spool 33, the annular coil 34, and the permanent magnet 35 are housed in the cylindrical housing part 31A, and then the synthetic resin body 38 containing the waveform shaping circuit 37 and the high frequency filter 39 are sequentially housed in the box-shaped housing part 31B. As a result, the assembly work of the electromagnetic pickup 30 can be simplified, and its external dimensions can be reduced to include the rod-shaped core 32, spool 33, annular coil 34, permanent magnet 35, and waveform shaping circuit that are arranged symmetrically. 37 as well as the high-frequency filter 39 can be made compact by arranging them in series.

After completing such assembly, when assembling the electromagnetic pickup 30 to the transmission 10, the cylindrical housing portion 31A of the casing 31 is fitted into the opening 11a of the output side housing 11 via the O-ring 13, and the casing is The support arm 31b of 31 may be fastened to the female threaded portion 11b of the output side housing 11 using a bolt llc. As a result, the assembly of the electromagnetic pink-up 30 is completed in a state in which the detection end 32a of the rod-shaped core 32 is directly opposed to any of the teeth 22 of the gear 20 with a predetermined gap therebetween.

However, when the assembly is completed like this,
Since the detection end 32a of the rod-shaped core 32 directly opposes the tooth 22 of the gear, the detection end 32a and the tooth 2 opposite thereto
2 can be set to an appropriate value, and as a result, the AC signal from the annular coil 34 can always be ensured at an output sufficient for detecting the rotational speed of the output shaft 12. In this case, since the bottom wall of the cylindrical container 31A of the casing 31 and the annular opening 31a are uniformly thin, the change in the magnetic flux generated from the detection end 32a of the rod-shaped core 32 causes the bottom wall to become thinner. Also, sufficient detection output can be ensured without causing unnecessary overcurrent loss in the annular opening 31a. Furthermore, even if the detection end 32a of the rod-shaped core 32 is exposed inside the output side housing 11 as described above, the detection end 32a
a is attached to the annular opening 3 of the casing 31 via the adhesive 36.
1a, the synergistic effect of this press-fitting state and the adhesive action of the adhesive 36 causes the output side housing 1
The intrusion of the /r11 oil in the spool 3 into the cylindrical housing portion 31A is always reliably blocked, and as a result, the spool 3
3. The annular coil 34, synthetic resin body 38, and waveform shaping circuit 37 can always be maintained in a normal state. In addition, since the adhesive 36 has oil resistance, lubricating oil and the output side housing 11
It will not deteriorate even if affected by the internal atmosphere.

Further, since only the cylindrical accommodating portion 31A formed by effectively utilizing the external dimensions of the rod-shaped core 32 is fitted into the opening 11a of the output side housing 11, the mounting space inside the output side housing 11 is reduced. Even if the housing is very narrow, the electromagnetic pickup 30 can be easily assembled to the output housing 11.

In such a case, even if the inside of the output side housing 11 becomes high temperature, since the waveform shaping circuit 37 is located outside the output side housing 11, this waveform shaping circuit 37 can directly absorb the influence of the high temperature inside the output side housing 11. I won't even receive it.

Furthermore, since the casing 31 that houses the annular coil 34 and the waveform shaping circuit 37 is made of aluminum material, it is possible to prevent high frequency noise caused by electromagnetic waves from entering the annular coil 34 and the waveform shaping circuit 37 by providing a special blocking member. Instead, it can be shut off by the casing 31 itself. In such a case, the high frequency filter 39 connects each external conductor jl! 1~
13 and the waveform shaping circuit 37,
High frequency noise that enters through each external conductor 11 to β3 also
The high frequency filter 39 reliably isolates the waveform shaping circuit 37 from the casing 31 and the transmission 10.
It flows into military law through.

Furthermore, if the above-described assembly order of the electromagnetic pickup 30 and its assembly to the transmission 10 are taken into consideration, it goes without saying that the electromagnetic pickup 30 can be easily disassembled and reassembled for maintenance inspection.

In the above embodiment, the detection end 32a of the rod-shaped core 32 was press-fitted as it is into the annular opening 31a of the casing 31 via the adhesive 36, but instead of this, for example, as shown in FIG. If the annular groove 32b is formed on the outer peripheral surface of the detection end 32a of the rod-shaped core 32, a large amount of the adhesive 36 will remain along the inside of the annular groove 32b when press-fitting into the annular opening 31a of the detection end 32a. , it is possible to improve oil tightness. This can be similarly achieved by providing an annular groove on the inner peripheral surface of the annular opening 31a.

Further, in the embodiment described above, the annular opening 31a of the casing 31 is made to protrude outward, but instead of this, the annular opening 31a may be made to protrude inward of the casing 31.

Further, in the above embodiment, the detection end 32a of the rod-shaped core 32 is press-fitted into the annular opening 31a of the casing 31, but the invention is not limited to this. It may be screwed on. In such a case, instead of the adhesive 36, a sealing tape or the like having a similar function may be used.

Further, in the embodiment described above, the waveform shaping circuit 37 is also housed within the casing 31, but the present invention is not limited to this, and it is also possible to additionally house an amplifier circuit or the like.

Further, in the above embodiment, the casing 31 is made of aluminum material, but the present invention is not limited to this, and the casing 31 may be made of a non-magnetic metal material or a conductive synthetic resin material. In such a case, each component housed in the casing 31 may be molded with a conductive synthetic resin material in the same position.

Furthermore, in the embodiment described above, after the rod-shaped core 32 is press-fitted into the annular opening 31a, the spool 33 is fitted into the rod-shaped core 32 and inserted into the cylindrical accommodating portion 31A, but the present invention is not limited thereto. After inserting the spool 33 into the cylindrical housing portion 31A, the rod-shaped core 32 may be press-fitted into the annular opening 31a.

[Brief explanation of drawings]

Fig. 1 is an assembled state diagram showing the present invention assembled into a transmission, Fig. 2 is an enlarged sectional view of the electromagnetic pickup in Fig. 1, Fig. 3 is a cutaway view of the same main part, and Fig. The figure is a sectional view of a main part showing a modification of the state in which the detection end of the rod-shaped core is press-fitted into the annular opening of the casing. Description of symbols 10... Transmission, 11... Output side housing, Ila... Opening, 12... Output shaft, 20
...Gear, 22...Teeth, 30...Electromagnetic pin 7 qua 7, 31...Casing, 31A...Cylindrical housing part, 31B...Box-shaped housing part, 32...・Rod-shaped core, 3
2a... Detection end portion, 34... Annular coil, 35...
・Permanent magnet, 37... Waveform shaping circuit.

Claims (1)

[Claims] A plurality of magnetic teeth are arranged along the circumferential direction of a rotating shaft supported in a housing of a transmission, and a plurality of magnetic teeth are inserted through an opening protruding from a peripheral wall of the housing. A rotational speed detector comprising a rod-shaped core having an inner end facing either side, an annular coil wound around the rod-shaped core, and an electromagnetic pickup having a permanent magnet provided at an outer end of the rod-shaped core. an electronic circuit connected to the annular coil; and a cylindrical first body that is fitted into the opening of the housing so as to face any one of the plurality of magnetic teeth and contains the rod-shaped core, the annular coil, and the permanent magnet. The electromagnetic pickup is provided with a conductive casing having a built-in part and a second built-in part that coaxially extends outward from an outer end of the first built-in part and houses the electronic circuit. Characteristic rotation speed detector.