JP2002214312A - Magnetic sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate manufacturing of a magnetic sensor and to enhance the precision and reliability. SOLUTION: This magnetic sensor comprises a sensor assembly and a resin molded product provided around the sensor assembly to form a housing. The sensor assembly comprises a magnet for generating a magnetic flux, a magnetic core for forming a magnetic circuit, a coil wound around the magnetic core to detect the change of the magnetic flux passing through the magnetic core, and a support body for supporting the magnet, the magnetic core and the coil as an assembly. The support body comprises a coil bobbin for receiving the magnetic core, a sleeve having one end connected to the coil bobbin to receive the magnetic core and the magnet, a spacer for retaining the magnetic core and the magnet within the sleeve, and a terminal provided on the other end of the sleeve and connected to the coil. The sleeve comprises a small diameter part for retaining the spacer by pressure fitting on the inside surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic sensor, and more particularly to a magnetic sensor for detecting a change in magnetic flux.
Such a magnetic sensor is generally used for position detection, rotation speed detection, and the like, and is particularly useful when used for position detection of an internal combustion engine.

[0002]

2. Description of the Related Art FIGS. 40 to 48 are views showing a conventional magnetic sensor related to the magnetic sensor of the present invention.
FIG. 43 to FIG. 43 are diagrams showing examples of use of a conventional magnetic sensor. In the conventional magnetic sensor 1, 2 is a cylindrical magnetic core, 3 is a coil wound around the magnetic core 2 between flanges 5 and 6 via a bobbin 4 made of resin, and 7 is a bobbin 4 , A cylindrical permanent magnet, 8 is a columnar permanent magnet, 9 is a spacer arranged on the magnet 8, 10 and 11 are lead wires drawn from the coil 3, 12 is a lead wire 10, A tape for fixing 11 to the sleeve 7, and a reference numeral 13 is provided at the other end of the sleeve 7, around which the lead wire 10 is wound, for example, solder (not shown).
The terminal is electrically connected and fixed by the connector, and is attached through the sleeve 7, and the other end extends into the connector portion 15 of the housing 14 of the magnetic sensor 1.

A housing 14 is a resin molded body provided around a sensor assembly including a magnetic core 2, a coil 3, a magnet 8, and the like of the magnetic sensor.
, A cylindrical main body 16 accommodating the sensor assembly, and a mounting bracket 17 for mounting the magnetic sensor 1 at a predetermined position. The mounting bracket 17 is provided with a positioning pin 18 and a hole 19 for receiving a mounting screw. The main body 16 of the magnetic sensor 1 has the support structure 2.
0, the positioning pin 18 of the mounting bracket 17 is inserted into the positioning hole 22 of the support structure 20, and the screw is inserted into the screw hole 23 of the support structure 20 through the hole 19 for receiving the mounting screw. Mounting screw 24 engaged
And is fixed at a predetermined position.

As shown in FIG. 40, such a magnetic sensor 1 is used by being mounted at a position where the tip of a magnetic core 2 can face the tip of a projection 25 of a rotating body 26 which is a signal detection plate made of a magnetic material. You. In such a state, the magnetic flux from the magnet 8 extends through the magnetic circuit including the magnetic core 2, but the protrusion 25 of the rotating body 26
Are periodically present at positions facing the tip of the magnetic core 2 in accordance with the rotation of. The magnitude of the magnetic flux passing through the magnetic core 2 changes between when the projection 25 is present at this position and when it is not present, because the magnetic resistance of the magnetic circuit changes. This change in magnetic flux is converted into a voltage by the coil 3 and
5 is output. In such a magnetic sensor,
In order to concentrate the magnetic flux emitted from the magnetic core and improve the position detection accuracy of the magnetic sensor, the tip of the magnetic core and the rotating body 2
6 and the same shape having substantially the same size, and paying attention to the mounting of the magnetic sensor, using the positioning pins 18 and the like, so that the front end surface of the magnetic core and the protrusion 25 are positioned exactly opposite to each other. I have to.

[0005]

FIG. 43 is a sectional view taken along line A- of FIG.
44 is an enlarged view of a portion of the bobbin 4 in which the lead wire 10 is drawn out from FIG. 40, and FIG. 45 is a cross-sectional view taken along the line A. FIG. FIG.

The bobbin 4 used for the magnetic sensor 1 has a cylindrical winding core 27 (see FIG. 40) around which the coil 3 is wound, and two disk-shaped flanges 5 and 6 provided at each end thereof. The flange 6 is provided with outlets 28 and 29 for the lead wires 10 and 11. The outlets 28 and 29 are cutouts extending from the outer edge of the flange 6 to the inside in a substantially radial direction so as to be separated from each other. In the illustrated example, the lead wire 10 enters from the inside end of the lead-out opening 28, is wound on the bobbin 4, forms a layer that is gradually stacked, and becomes the coil 3. From the outside edge of the Therefore, as can be clearly understood from the drawing, the lead wire 11 comes out of the flange 6 from a position radially outward of the drawer port 29 and moves out of the sleeve 7.
The sleeve 7 extends radially inward, extends axially on the sleeve 7 together with the lead wire 10, is fixed by a tape 12, and is wound around the terminal 13 at the other end of the sleeve 7.

As described above, since the lead wire 11 has a portion which is wired in the radial direction, a tensile stress is applied to the lead wire 11 and the pressure of the molten resin or the like is applied when the resin molded body 16 as a housing is formed. There is a problem that the lead wire 11 may be disconnected. Also, since the lead wire 11 is passed through the shallow part of the outlet 29,
There is a problem in that the position is not determined due to being detached from the outlet 29.

The lead wires 10 and 11 are fixed by soldering after being wound around the terminal 13 at the connection portion.
During the soldering operation, there is also a problem that the bobbin 4 and the sleeve 7 are damaged by melting or burning due to a high-temperature solder or a soldering iron. Further, since the connecting portions between the lead wires 10 and 11 and the terminals 13 are arranged in the cylindrical housing body 16, the connecting portions are prevented from protruding radially outward from the bobbin 4. For this reason, immersion in a solder bath cannot be used for the soldering work, and manual work using a soldering iron has to be performed, which makes automation of the soldering work difficult and increases the product price.

In FIG. 45, the coil 3 is wound around the bobbin 4,
FIG. 4 shows a partial plan view of the sensor assembly in which the lead wires 10 and 11 have also been wired by the tape 12. The tape 12 must be made of an expensive heat-resistant material that can withstand high temperatures during a soldering operation or a resin molding operation, which is one of the reasons why the price of the product cannot be reduced. In addition, the wiring operation using the tape 12 is performed before the winding and soldering operation around the terminal 13.
That is, it has to be carried out immediately after the winding operation of the coil 3, and there has been a problem that a dedicated machine or another manual process is required for this operation.

FIG. 46 is a schematic sectional view showing a mold used in a resin molding process of the conventional magnetic sensor 1, and includes a magnetic core 2, a coil 3, a bobbin 4, a sleeve 7, a magnet 8, a spacer 9, and the like. The assembly is housed and supported in a cavity 33 formed by molds 30, 31, and 32. That is, the tip of the magnetic core 2 is fitted exactly into the concave portion 34 provided on the bottom surface of the cylindrical cavity of the lower mold 30, and the upper end portion of the terminal 13 serving as the connector 15 is inserted into the core mold 31. Inserting and holding the upper mold 32 over it to form a cavity 33, the sensor assembly is held in place within the cavity 33.

In a magnetic sensor using such a resin molding die, the magnetic core 2 moves due to the pressure of the injected resin during resin molding, and the center axis is inclined and eccentric.
There has been a problem that the output of the magnetic sensor becomes unstable and the product value is significantly reduced. Further, since the terminal 13 is supported by the core mold 31, there is a problem that the terminal 13 is bent by the pressure of the injected resin.

On the other hand, the signal extraction of the magnetic sensor
In the case of using a lead wire without using 3, the sensor assembly is supported at one point only by the magnetic core 2 in the cavity 33 of the mold, and is unstable, so that the resin molding operation is difficult.

In order to obtain the stability of the support in the mold, it is considered that the concave portion 34 of the lower mold 30 is deepened to make the protrusion of the magnetic core 2 sufficiently long. When the magnetic core 2 is lengthened in the magnetic circuit of the above, there is also a problem that the signal output of the magnetic sensor 1 decreases because the magnetic resistance increases in proportion thereto. Furthermore,
When the protruding portion of the magnetic core 2 becomes longer, its exposed area becomes larger, foreign substances of a magnetic substance such as iron powder are easily adsorbed, and the magnetic circuit of the magnetic sensor 1 is changed, for example, to decrease the signal output and to reduce the signal generation timing. There was a problem of causing displacement.

In the example of the magnetic sensor shown in FIG.
For example, to reduce the axial dimension of the sensor assembly when there are restrictions on the axial dimension of the completed magnetic sensor,
A part of the spacer 9 protrudes from the sleeve 7 and protrudes in the axial direction. In such a case, the contact area or contact area between the spacer 9 and the sleeve 7 is small, and the stability of the spacer 9 in the resin injection step for resin molding is poor. Need to be fixed with a cyano-based adhesive or the like. When the adhesive is used as described above, the number of steps in the manufacture of the magnetic sensor is increased and the product price is increased. The injected adhesive passes between the sleeve 7 and the spacer 9 and enters between the spacer 9 and the magnet 8 to form a thin film of the adhesive, that is, a gap layer. However, there is also a problem that the magnetic resistance of the magnetic sensor increases and the output of the magnetic sensor decreases.

The conventional magnetic sensor shown in FIG. 47 has a sealing function. The main body 16 of the magnetic sensor is inserted into a mounting hole 21 formed in the support structure 20 as shown in FIG. Can be sealed. For this purpose, a circumferential groove 35 is provided around the housing body part 16.
, And an O-ring 36 is provided which comes into close contact with the inner peripheral surface of the mounting hole 21 of the support structure 20.

FIG. 48 shows a mold used in a resin molding step for manufacturing a magnetic sensor having such an O-ring 36. In this figure, a molding die for forming a resin molded body 14 serving as a housing is configured so that a shaft of a sensor assembly is arranged laterally and a connector portion 15 is arranged downward in a cavity 33 thereof. A core mold 38 for the connector 15 is inserted into the lower mold 37, and the upper molds 39 and 40 are arranged on the lower mold 37. The reason why the axis of the sensor assembly is arranged laterally is to prevent the circumferential groove 35 of the housing body portion 16 from being undercut.

When the sensor assembly in which the spacer 9 protrudes from the sleeve 7 as described above is placed in the mold, the risk of the spacer 9 falling off the sleeve 7 is further increased. It is necessary to fix the magnetic sensor firmly and firmly, the workability is poor, the unit price of the product is increased, and the sensitivity of the completed magnetic sensor may be deteriorated.

Further, in the resin molding of the magnetic sensor,
For the purpose of reducing the size of the magnetic sensor and reducing the diameter of the housing main body, the thickness of the housing main body 16 is reduced at the portion accommodating the coil 3 as shown in FIGS. Are particularly thin at the portions of the flanges 5 and 6. In order to make such a configuration, the gap between the resin molding die and the flanges 5 and 6 is set to be small. For this reason, the injected resin is unlikely to enter the gap during resin molding, and there is even a risk that the resin molding is not completely performed due to the so-called poor running of the molten metal and a cavity is generated.
In order to improve the poor running of the molten metal, for example, a method of increasing the resin injection speed or increasing the resin molding pressure may be considered, but the lead wire outlet 28 of the flange 6 of the bobbin 4 may be used.
There is a problem that the lead wires 10 and 11 coming out of the pipe 29 (FIG. 43) are broken by the pressure of the resin.

Further, regarding the positioning of the mounting base or the like with respect to the support structure 20, the mounting bracket is set in a plane parallel to the axial direction of the magnetic sensor, and the main body housing the sensor assembly is not inserted into the through hole of the support structure. In addition, in a magnetic sensor that performs positioning by using a projection provided on a mounting bracket, the distance between the tip of the magnetic core and the positioning projection becomes longer, and the positioning accuracy of the tip of the magnetic core due to the positioning projection deteriorates. was there. Further, when the positioning projection is separately attached to the mounting bracket as a separate component from the mounting bracket, the number of components increases, and the work of assembling the positioning projection to the mounting bracket is required. There was a problem.

As an example of the positioning method, the inner diameter of the through hole for receiving the screw of the mounting bracket is made slightly larger than the outer diameter of the male screw portion (not shown) of the mounting screw. When fixing the magnetic sensor while positioning it by inserting the mounting screw, the dimensional tolerance of the inner diameter of the through hole must be reduced. For this reason, there is a problem that it is difficult to process the through-hole, and it is necessary to use a cut bush or the like, thereby increasing the product unit price.

The present invention has been made to solve the above-described problems of the conventional magnetic sensor, and an object thereof is to provide a magnetic sensor which is easy to manufacture, inexpensive, and has high accuracy and reliability. It is.

[0022]

In order to achieve this object, a magnetic sensor according to the present invention comprises a sensor assembly and a resin molded body provided around the sensor assembly to form a housing. The sensor assembly includes a magnet that generates a magnetic flux, a magnetic core that forms a magnetic circuit, a coil that is wound around the magnetic core and detects a change in magnetic flux passing through the magnetic core, the magnet, A support for supporting the magnetic core and the coil as an assembly, wherein the support is a coil bobbin for receiving the magnetic core;
A sleeve connected at one end to the coil bobbin to receive the magnetic core and the magnet; a spacer for holding the magnetic core and the magnet in the sleeve; and a spacer provided at the other end of the sleeve and connected to the coil. And a small-diameter portion provided on the inner peripheral surface of the sleeve for holding the spacer by interference fit.

According to a second aspect of the present invention, the small diameter portion is a projection protruding from the inner peripheral surface of the spacer.

[0024]

According to the magnetic sensor of the first aspect, the magnetic core, the magnet and the spacer can be fixed in the support by press-fitting without using an adhesive, and automation is possible.

In the magnetic sensor according to the second aspect, press-fitting for press-fitting is easy.

[0026]

1 to 3 show a reference example of a magnetic sensor which can be used with the present invention. The overall configuration of a magnetic sensor 41 that can be used with the present invention is similar to the magnetic sensor shown in FIGS.
2 and a resin molded body 43 provided to surround the sensor assembly 42 and form a housing of the magnetic sensor 43.

The sensor assembly 42 includes a relatively thick disk-shaped permanent magnet 44 for generating a magnetic flux, a magnetic core 45 for forming a magnetic circuit for the magnetic flux, and a magnetic core 45 wound around the magnetic core 45. A coil 46 for detecting a change in magnetic flux passing through 45, a support 47 for supporting the magnet 44, the magnetic core 45, and the coil 46 in a predetermined electromagnetic induction relationship as an assembly 42, and a support 47 pulled out of the coil 46
A terminal 52 having a connection portion 51 to which lead wires 49 and 50 secured with a tape 48 are connected. The support 47 is fitted to the magnetic core 45 and has flanges 53 and 54 provided at both ends of the winding core 63.
6, a cylindrical sleeve 56 which extends in the axial direction from the bobbin 55 and receives the magnet 44 therein, and is inserted into the sleeve 56 to hold the magnet 44 in a predetermined position. Magnetic spacer 57
And The bobbin 55 and the sleeve 56 integrally formed are made of, for example, PBT (polybutylene terephthalate), PP (polypropylene), nylon, epoxy resin, or the like.

The resin molded body 43 which is the housing of the magnetic sensor 41 is made of the same material as the support 47. The resin molded body 43 has a cylindrical main body portion 5 that covers and covers substantially the entire sensor assembly 42 except for the tip end 58 of the magnetic core 45.
9, a connector portion 60 extending radially from the main body portion 59 and having a terminal 52 therein, and a mounting bracket 61 extending radially opposite to the connector portion 60 from the main body portion 59. As shown in FIG. 42, the mounting bracket 61 has a mounting hole 62 with a bush for fixing the mounting bracket 61 to the support structure through a mounting screw.

The magnetic sensor 41 which can be used with the present invention is provided on a flange 53 of a coil bobbin 55 of a support member 47, which is exposed from two circular openings 64 provided on an end face of a main body portion 59 of a resin molded body 43. The joint 65 is provided. In this example, the engaging portion 65 is provided as shown in FIGS.
When the resin molding 43 is formed by the molding die 66 on the projection surface as shown in FIG. 3, the sensor is fitted and engaged with the recess formed by the two annular projections 67 provided on the die 66. The assembly 42 is positioned and supported at a predetermined position in the molding die 66. The engaging portion 65 has a circular planar shape, but may have any other shape.

In the magnetic sensor 41 configured as described above, the support in the molding die 66 is not only supported by the engagement between the tip 58 of the magnetic core 45 and the concave portion of the molding die 66 but also by the bobbin. Since the engagement portion 65, which is the two projection surfaces provided on the flange 53 of the 55, can be supported by engagement with the annular projection 67 of the molding die 66, the shaft of the sensor assembly 42 in the molding die 66 can be obtained. The positioning support including the tilt of the lens and the rotation around the axis becomes stable and accurate.

Further, the positioning support can be performed only by the engagement between the engagement portion 65 and the annular projection 67 of the molding die 66.
Similar effects can be obtained even if the tip 58 of the magnetic core 45 is not engaged with and supported by the molding die 66 as in the magnetic sensor 9.

In the magnetic sensor which can be used with the present invention shown in FIGS. 4 to 6, the resin 53 is formed on the flange 53 of the coil bobbin 55 of the support member 47 in the same manner as the engaging portion 65 shown in FIGS. It has an engagement portion 68 exposed from two circular openings 64 provided on the end face of the main body portion 59 of the body 43. The engaging portion 68 is not a projection surface but a flat surface, and abuts and engages with two projections 70 provided on the mold 69 when the resin molding 43 is molded by the molding mold 69. The sensor assembly 42 is positioned and supported at a predetermined position in the molding die 69.

In the magnetic sensor 41 configured as described above, the support in the molding die 69 is not only supported by the engagement between the tip 58 of the magnetic core 45 and the concave portion of the molding die 69, but also by the bobbin. Since the two flat surfaces of the engagement portion 68 provided on the flange 53 can be supported by abutting engagement with the two projections 70 of the molding die 69, the sensor assembly in the molding die 69 can be obtained. The positioning support such as the inclination of the axis 42 is stable and accurate. In this example, the engaging portion 68 is a flat surface having a circular planar shape, but the same effect can be obtained even if the engaging portion 68 has any other planar shape or a surface that is not flat but has a depression.

FIGS. 7 and 8 show a modification of the coil bobbin 55 of the magnetic sensor that can be used with the present invention. The coil bobbin 55 is provided with outlets 72 and 73 for passing lead wires 49 and 50 (not shown) to the flange 71 on the sleeve 56 side. The lead wires 49, 50, which are approximately 180 degrees apart in the direction and pass through the outlets 72, 73, are prevented from contacting each other on the sleeve 56. In such a magnetic sensor using the coil bobbin 55, the lead wire 49 arranged on the sleeve 56 is passed through the outlet 72 of the flange 71 and wound on the bobbin 55 to form the coil 46. At the end, the lead-out tape 73 is again attached to the sleeve 56 from the lead-out port 73 which is 180 degrees apart in the circumferential direction and is connected to the connection portion 51 of the terminal 52 by solder or the like. When such a bobbin 55 is used, the outlets 72, 7
Since the distance between the lead wires 49 and 50 passing through the sleeve 3 and onto the sleeve 56 increases, it is possible to prevent a short circuit due to contact with each other.

For reference, the coil bobbin 55 shown in FIG.
Are inclined so that two outlets 76 (only one is shown) provided in a flange 75 on the sleeve 56 side are close to the winding direction of the lead wires 49, 50 of the coil 46 on the coil bobbin 55. And lead lines 49, 5
0 is not bent at a sharp angle at the outlet 76. In other words, the axis of the outlet 76 is inclined with respect to the flange 75 so as to form an acute angle, for example, 45 degrees with respect to the direction in which the lead wires 49 and 50 extend in the coil 46.

In the magnetic sensor having the coil bobbin 55 configured as described above, the contact between the lead wires 49 and 50 and the outlet 76 is light contact, that is, the contact is light, and the lead wires 49 and 50 Since the bending is also reduced, disconnection of the lead wires 49, 50 due to the tension acting on the lead wires 49, 50 during coil winding can be prevented.

For reference, the height of the outer peripheral surface of the sleeve 78 is changed in the support 47 shown in FIGS.
The outlets 80, 81 of the lead wires 49, 50 formed on the flange 79 of the coil bobbin 55 extend substantially in parallel from the outer edge of the flange 79 toward the inside and are spaced apart from each other. The lower end of the sleeve 78 is relatively deep, and the inner end of the outlet 81 is relatively high in the higher portion of the sleeve 78 and relatively shallow, and has substantially the same radial direction as the outer periphery of the coil 46 wound around the coil bobbin 55. In position. The lead wire 49 extends along the lower portion of the sleeve 78, passes through the flange 79 from the deep position of the drawer port 80, enters the coil bobbin 55, is wound around the coil, and extends axially from the outer periphery of the coil to form the drawer port 81. And is pulled out of the flange 79 to a higher portion of the sleeve 78.

In the support 47 having the coil bobbin 55 having such a configuration, the distance between the two outlets 80 and 81 is relatively large both in the circumferential direction and in the radial direction. A short circuit accident of the wires 49 and 50 can be prevented, and since there is no need to bend the lead wire in the radial direction, excessive tension does not act on the lead wire and disconnection can be prevented.

FIG. 12 shows a perspective view of yet another sensor assembly 42 for use with a magnetic sensor that can be used with the present invention. The support 84 of the sensor assembly 42
Has a coil bobbin 55 similar to that shown in FIG.
Lead wires 49, 50 drawn from draw-out ports 72, 73 of the flange 71, which are 180 ° circumferentially separated from each other, are wound around the sleeve 56. In this figure, a terminal block 85 for holding the terminal 52 is provided at the tip of the sleeve 56, and the lead wire 49 is wired in the axial direction on the sleeve 56 to reach the connection part 51 with the terminal 52. Reference numeral 50 is wound around the sleeve 56 until it reaches the connection portion 51 from the drawer port 73 and makes about a half circumference.

According to such a configuration, the outlet 7
Since the distance between the lead wires 49 and 50 coming out of 2, 73 and wired on the sleeve 56 is large, a short circuit accident of the lead wires 49 and 50 particularly on the sleeve 56 near the flange 71 can be prevented. FIG. 12 shows two outlets 72 and 73.
Are arranged 180 degrees apart from each other, but the same effect can be obtained if the circumferential distance between the two outlets 72, 73 is 45 degrees or more. Further, either of the two lead wires 49 and 50 or both of them may be wound.

In the sensor assembly 42 of the magnetic sensor which can be used with the present invention shown in FIGS. 13 and 14, a parallel flange 86 is provided on the outside of the flange 71 of the coil bobbin 55 in the axial direction. Thus, a circumferential groove 87 is formed therebetween. Flange 86 has substantially the same diameter as flange 71. The flange 86 is provided with a radial slit 88 at a position circumferentially separated from a draw-out opening (not shown) of the flange 71, and a lead-out line 49 drawn from the flange 71 of the bobbin 55.
Alternatively, 50 is wound through the circumferential groove 87 and pulled out of the slit 88 onto the sleeve 56.

According to this configuration, since the lead wire 49 or 50 is wound around the circumferential groove 87, the distance between the two lead wires 49 and 50 can be increased to prevent a short circuit, and the lead wire 49 or 50 can be prevented. Can be prevented from shifting in the axial direction to prevent disconnection. In this example, the flange 86 is used. However, as long as the circumferential groove 87 can be formed, a structure of another shape may be adopted instead of the separate flange 86 as shown. Further, two slits 88 provided in the circumferential groove 87 are provided, and the lead wires 49 and 50 are formed in the circumferential groove 8.
7 and can be pulled out from each slit.

For reference, in the sensor assembly 42 shown in FIGS. 15 and 16, the sleeve 90 has two parallel axial grooves 91 and 92 which are separated from each other, and is pulled out from the flange 71 of the coil bobbin 55. Lead wire 49,
50 are wired in these axial grooves 91, 92,
It extends to a terminal 52 not shown.

In the magnetic sensor using the sensor assembly 42 having such a configuration, the lead wires 49 and 50 are buried in the axial grooves 91 and 92 of the sleeve 90. The short circuit can be prevented by preventing circumferential displacement of the 50.

FIGS. 17 and 18 are perspective views showing another example of the sensor assembly 42 of the magnetic sensor which can be used with the present invention.
Has a coil bobbin 55 similar to that shown in FIG. 10 and has two coil outlets 80 and 81 which are separated in the circumferential direction of the flange 71. The lead wires 49 and 50 are wound around the sleeve 56. In this figure, the sleeve 56 has an engagement protrusion 95 on its cylindrical peripheral surface at a position approximately 90 degrees away from the outlet 81 in the circumferential direction.
The lead wire 49 is drawn out from the inner end of the outlet 80 and is wired along the sleeve 56 in the axial direction substantially parallel to the axis, while the lead wire 50 is drawn from the outer end of the drawer 81 and The engagement projection 9 along the cylindrical surface of 56
5, it extends spirally downward when viewed from the outlet 81, is hung around the engagement projection 95, extends spirally again, and is wired to the connection portion 51 of the terminal 52 of the terminal block 85.

According to such a configuration, the outlet 8
Since the distance between the lead wires 49 and 50 coming out of 0 and 81 and wired on the sleeve 56 is widened by the engaging projections 95, the distance between the lead-out ports 80 and 81 and the distance between the terminal connection portions 51 are small. Even if it is small, a short circuit accident of the lead wires 49 and 50 on the sleeve 56 can be prevented.

In the reference example shown in FIG. 19, the engagement projection 96 on the sleeve 56 has an engagement groove 97 on the lower surface when viewed from the drawer port 81, and the lead wire 49 is 9
7 and is hung around the engagement protrusion 96.

In this reference example, the lead lines 49, 5
A short circuit accident due to contact between zero can be prevented, and the lead wire 49 inserted into the engagement groove 97 does not easily come off the engagement projection 96, so that the displacement and disconnection of the lead wire 49 can be prevented.

In the sensor assembly 42 of the magnetic sensor which can be used with the present invention shown in FIGS. 20 and 21 for reference, a magnet 44, a magnetic core 45, a coil 46
Are supported by the magnetic core 45.
And a sleeve 56 connected at one end to the coil bobbin 55 to receive the magnet 44.
And the engaging recess 9 provided integrally with the other end of the sleeve 56.
9, and a terminal 52 provided on the terminal block 100 and connected to lead wires 49 and 50 from the coil 46 at a connection portion 51. A positioning recess 102 is formed on the upper end surface of the spacer 101 holding the magnet 44 in the sleeve 56.

The engaging recess 99 of the terminal block 100 is a relatively elongated groove formed so as to surround the hole of the sleeve 56 along each side of the rectangular terminal block 100 in the illustrated example.
When the sensor assembly 42 is resin-molded,
Penetrates into the engaging concave portion 99, the area of the contact interface between the resin molded body 43 and the terminal block 100 is increased, and the adhesion is improved.

In order to accurately and stably support the sensor assembly 42 in the molding die during resin molding, the tip of a core pin (not shown) of the molding die is positioned in the positioning recess 102 of the spacer 101. , And supported by engaging the leading end 58 of the magnetic core 45 with the concave portion of the molding die to provide two-point support. In this case, the completed resin molded body 43 has a through hole 103 which is a trace of a core pin.
Is formed, and the positioning concave portion 102 of the spacer 101 is exposed. 20 and FIG. 2 even if a conductive fluid such as rainwater may enter the through hole 103.
If a terminal block having an engagement recess 99 as shown in FIG.
The boundary surface between the resin molded body 43 and the terminal block 100 is wide,
The distance of the terminal 52 to the connection portion 51 is increased, and a short circuit due to moisture can be prevented.

For reference, the sensor assembly 42 shown in FIG.
Is provided at the other end of the sleeve 56 and the coil 4
The connection portion 51 of the terminal 52 connected to 6 protrudes radially outward from the outer diameter of the coil bobbin 55. 20 and 21, the terminal 52 is also connected to the terminal block 100.
Is provided in the connection portion 51 of the terminal 52.
22 is the same as that in FIG. 22 in that the connecting portion 51 projecting in the radial direction is
Embedded in the thickness of the mounting bracket 61,
The diameter of the main body portion 59 of the resin molded body 43 is not increased.

According to this configuration, the connecting portion 51 is oriented downward with the axis of the sensor assembly 42 oriented sideways, and immersed in a solder bath 105 in a solder bath 104 as shown in FIG.
Even if soldering is performed, other parts of the sensor assembly 42 such as the coil 46 and the coil bobbin 55 do not come into contact with the high-temperature solder bath 105. Can be automated, and workability is significantly improved.

Embodiment 1 FIG. FIGS. 23 to 25 show a sensor assembly 42 of the magnetic sensor of the present invention. The sensor assembly 42 has three axially long protrusions 110 protruding from the inner peripheral surface 109 on the inner peripheral surface 109 of the through hole 108 of the sleeve 56 of the support 47. The protrusion 110 is located radially inward of the inner peripheral surface 109,
Since the diameter of the circle in contact with the protrusion 110 is smaller than the diameter of the inner peripheral surface 109, it can be said that the circle is the small diameter portion of the inner peripheral surface 109. The outer diameter of the spacer 57 is
25, and the length of the protrusion 110 is a length corresponding to the position where the spacer 57 of the sleeve 56 enters, as is apparent from FIG. 44 is supported by the inner peripheral surface of the through hole 108 of the sleeve 56.

When assembling the sensor assembly 42, first, the magnetic core 45 is inserted into the through hole 108 of the sleeve 56.
Is inserted so that the tip end thereof comes out of the coil bobbin 55, then the magnet 44 is inserted into contact with the magnetic core 45, and finally, the spacer 5 is inserted into the through hole 108 of the sleeve 56.
Insert 7 At this time, since the outer diameter of the spacer 57 is larger than the circle in contact with the protruding portion 110 and smaller than the through hole 108, the spacer 57 is inserted into the through hole 108.
Is inserted into the sleeve 5 with pressure.
6 will be held by a press fit. In the illustrated example, the protrusions are three protrusions, but the number and shape of the protrusions are arbitrary as long as the spacers 57 can be press-fitted into the through holes 108 of the sleeve 56. Further, the protrusion 110 can be provided on the spacer side.

In the sensor assembly 42 having such a configuration, the magnetic core 45 and the magnet 44 can be held at predetermined positions by press-fitting the spacer 57 into the through hole 108 of the sleeve 56. Can be made simple and easy, and automation can be made easily.

The sensor assembly 4 of the magnetic sensor which can be used with the present invention shown in FIGS. 26 to 29 for reference.
2, a key groove 112 is formed in the through hole 111 of the sleeve 56 so as to extend over the entire length thereof, and a key 114 is formed in the flange 113 of the magnetic core 45 to fit into the key groove 112. The front end 115 of the magnetic core 45 is chamfered in parallel from both sides, and the end face 116 is formed in an oval or oblong shape. The end surface 116 of the magnetic core 45 is formed into an elliptical shape in this way, and its axis is a detection target (for example, FIG.
If it is arranged at right angles to the moving direction of the detection piece 25) of the rotating disk 26 of 0, the rising of the output signal becomes sharp and the detection of the position of the detection target becomes accurate. Therefore, the direction of the axis of the oval end face 116, that is, the rotational position of the magnetic core 45 around the central axis is important.

In assembling, key 114 is inserted into keyway 1
When the magnetic core 45 is inserted into the sleeve 56 by engaging with the magnetic core 12, the position around the axis of the magnetic core 45 is determined, and therefore, the axis of the oval end surface 116 of the tip 115 of the magnetic core 45 is also determined. If the mounting of the magnetic core 45 is performed correctly, the posture of the end face 116 of the magnetic core 45 can be correctly set in a predetermined direction. In this sense, the sleeve 56
The key groove 112 and the key 114 of the magnetic core 45 can be said to be a positioning device provided between the magnetic core 45 and the sleeve 56 and engaged with each other to position the magnetic core 45 with respect to the sleeve 56. The same effect can be obtained by providing the key groove in the magnetic core and providing the key in the sleeve.

A magnetic sensor 120 which can be used together with the present invention shown in FIGS. 30 and 31 includes, for reference, a sensor assembly 42 and a resin molded body 121. The sensor assembly 42 includes a magnet 44 and a magnetic core. 45, coil 4
6, a spacer 57 and a support body 47 for holding these in a predetermined positional relationship to form an assembly. The resin molding 121 surrounds the sensor assembly 42 with the leading end 58 of the magnetic core 45 protruding, and forms a housing of the magnetic sensor 120. A resin molded body 121 of the magnetic sensor 120 includes a cylindrical main body 122 surrounding the sensor assembly 42 and housing a connector (not shown), and a magnetic sensor 120 extending radially outward from the main body 122.
Mounting bracket 124 having a mounting hole 123 in a direction perpendicular to the axis of the magnetic core 4 protruding from the resin molded body 121.
5 is a positioning device which is a positioning device provided protruding from the cylindrical surface of the resin molded body 121 in the vicinity of the tip 58 of the resin molding 121.
5 is provided. The positioning pin 125 extends in a direction perpendicular to the axis of the magnetic sensor 120, similarly to the mounting hole 123 of the mounting bracket 124.

As shown in the figure, such a magnetic sensor 120 is mounted on a mounting base 126 as a support structure with its axis parallel to the axis. That is, the mounting bracket 124 is placed parallel to the mounting pedestal 126, and the mounting hole 123 is aligned with the screw hole 127 of the mounting pedestal 126, and can be firmly fixed by the screw 128 as shown in FIG. The positioning pin 125 is also fitted in the positioning hole 129 of the mounting base 126 to accurately position the tip 58 of the magnetic core 45 of the magnetic sensor 120 with respect to the mounting base 126. Unlike the conventional magnetic sensor shown in FIGS. 40 to 42, it is not necessary to fit the main body into the opening of the mounting base.

In such a magnetic sensor 120,
Positioning pin 1 very close to tip 58 of magnetic core 45
Since the 25 is provided, the positioning accuracy can be made extremely high. This is a very useful advantage in a magnetic sensor, since it is generally necessary to precisely maintain the distance between the magnetic core and the signal detection plate in order to reduce the variation in the output signal. is there. In addition, since it is not necessary to penetrate the main body portion of the magnetic sensor through the mounting pedestal and the magnetic sensor can be arranged in parallel with the mounting pedestal, the degree of freedom in arranging the magnetic sensor is large.

FIGS. 32 and 33 show still another reference example of a magnetic sensor that can be used with the present invention. This magnetic sensor is a sensor assembly 1 having a magnetic core 45.
30, a resin molded body 131 that protrudes the tip 58 of the magnetic core 45 to form a housing of the magnetic sensor around the sensor assembly 130, and a resin molded body 131 of the magnetic core 45.
Covers 133 and 134 at least partially surround the side surface 132 of the distal end 58 protruding therefrom.

In the example of FIG. 32, the tip 58 of the magnetic core 45
The cover 133 surrounding the side surface 132 of the magnetic core 45 is a coating 133 extending integrally over the entire length along the tip end 58 of the magnetic core 45. FIG. 33
In the example, the side surface 132 of the distal end 58 of the magnetic core 45 protruding and extending from the resin molded body 131 is integrally and continuously extended from the coil bobbin 55 of the support body 47 and extends over the entire length along the distal end 58. Covered by the covering 134. In each case, the end surface 135 of the tip 58 is not covered.

In the magnetic sensor thus configured, since the side surface 132 of the tip 58 of the magnetic core 45 is covered with the resin coating 133 or 134, the foreign matter of the magnetic substance is attracted to the side surface of the magnetic core 45. In addition to preventing corrosion, the corrosion resistance can be improved. Coating 1
33 or 134 is the side surface 1 of the tip 58 of the magnetic core 45.
Although a certain effect can be obtained by covering a part of the side 32, it is desirable to cover the entire side surface 132. Magnetic core 4
Since the end face 135 of No. 5 is not coated, it does not disturb the magnetic detection.

In the reference example shown in FIGS. 34 to 37, the magnetic sensor includes a sensor assembly 136 and a resin molded body 137 provided around the sensor assembly 136 to form a housing. In addition, a circumferential groove 139 is formed in the cylindrical main body portion 138 of the resin molded body 137, and an O-ring 140 is fitted in the circumferential groove 139. The sensor assembly 136 includes a magnet 44 for generating a magnetic flux and a magnetic core 45 for forming a magnetic circuit.
A coil 46 wound around the magnetic core 45 to detect a change in magnetic flux passing through the magnetic core 45;
4, a support 47 for supporting the magnetic core 45 and the coil 46 as an assembly.

The support 47 includes a coil bobbin 55 for receiving the magnetic core 45 and winding the coil 46, a sleeve 56 connected at one end to the coil bobbin 55 for receiving the magnetic core 45 and the magnet 44, a magnetic core 45 and the magnet 44. Spacer 57 for holding the inside of the sleeve 56
A terminal 52 provided at the other end of the sleeve 56 and connected to the coil 46; and a cap 142 for holding the spacer 57 inside the sleeve 56. Cap 142
Is the same as or the same as the resin material of the resin molded body, and it is particularly desirable to use a resin having the same thermal expansion coefficient as that of the resin molded body. Examples of such materials are PBT, PP,
Nylon and epoxy resin.

The cap 142 has, for example, a shape as shown in FIG. 36 and is fitted to a portion of the spacer 57 protruding from the sleeve 56, and is fixed to the edge of the sleeve 56 at its edge 143 by an adhesive. . As shown in FIG. 37, the cap may be a cap 145 having an engagement piece 144. In this case, the engagement piece 14 of the cap 145 may be used.
Numeral 4 is elastically engaged with and fixed to a concave portion (not shown) formed on the outer periphery of the sleeve 56.

Such a cap 142 or 145
Is a circumferential groove 1 for the O-ring 140 as shown in FIG.
When the magnetic sensor 41 having the 39 is formed by resin molding, as described above, the circumferential groove 139 is not undercut (forming a protruding portion of the molding die that hinders extraction). When the sensor assembly 136 is placed in the molding dies 37 to 40 with the axis thereof set horizontally and the terminals 52 facing downward, the sensor assembly 136 is used.
Has the effect of preventing the spacer 57 from dropping off the sleeve 56 when it is placed horizontally. At this time, since the magnet 44 has not been magnetized yet, there is a danger that the spacer 57 will fall off. As described above, in the sensor assembly, the magnetic core, the magnet, and the spacer can be securely held in the sleeve even before the resin molding, and the manufacturing operation can be automated. Further, since the cap 142 can be adhered to the spacer 57 with a small amount of adhesive, there is no possibility that the adhesive may enter between the spacer 57 and the magnet 44 and cause magnetic resistance. If the cap 145 having the elastic engagement piece 144 shown in FIG. 37 is used, no adhesive is required, and the cap 145 can be fixed in one operation.
Good workability. The number and shape of the engagement pieces 144 are arbitrary as long as the cap 145 can be fixed to the sleeve 56.

In the reference example of the magnetic sensor which can be used with the present invention shown in FIGS. 38 and 39, the outer periphery of the outer periphery of the coil 46 of the flange 151 of the coil bobbin 150 of the support member 47 is provided outside. Are provided with a plurality of notches 152. The notch 152 is a resin passage for allowing the molten resin to flow therethrough when the sensor assembly is put into a molding die and molded with resin.

Although the shape and number of the notches 152 can be variously modified, the winding operation of the coil 46, the wound coil 46,
It should not adversely affect the flow of the injected resin (running hot water). For example, the number of the notches 152 may be one. Notch 15
2 may be provided only on the other flange 153 or on both flanges 151, 153. Further, the diameter of the entire circumference or a part of the flange 151 may be the same as the diameter of the wound coil 46 without being limited to the shape of the notch 152.

In this magnetic sensor, the molten resin is not hindered by the flange 151 or 153 of the coil bobbin 150 during the molding of the resin, and the flow of the molten resin in the molding die, that is, the run of the molten metal, is improved. The size can be reduced and the product yield can be improved.

[0072]

According to a first aspect of the present invention, there is provided a magnetic sensor comprising: a sensor assembly; and a resin molded body provided around the sensor assembly to form a housing. The sensor assembly includes a magnet for generating a magnetic flux. And a magnetic core forming a magnetic circuit;
A coil wound around the magnetic core to detect a change in magnetic flux passing through the magnetic core, and a support for supporting the magnet, the magnetic core and the coil as an assembly, the support comprising a coil bobbin for receiving the magnetic core, A sleeve connected at one end to the coil bobbin to receive the magnetic core and the magnet;
A small-diameter portion provided with a spacer for holding the magnetic core and the magnet in the sleeve, and a terminal provided on the other end of the sleeve and connected to the coil, and provided on the inner peripheral surface of the sleeve for holding the spacer by pressure fitting; , The magnetic core, the magnet and the spacer can be fixed in the support by press-fitting without using an adhesive, and automation is possible.

In the magnetic sensor according to the second aspect, since the small-diameter portion is a projection protruding from the inner peripheral surface of the spacer, it is easy to press-fit for pressure fitting.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a reference example of a magnetic sensor that can be used with the present invention.

FIG. 2 is an end view showing an engaging portion for positioning of the magnetic sensor of FIG. 1;

FIG. 3 is a partial sectional view showing a state where the magnetic sensor of FIG. 1 is arranged in a molding die.

FIG. 4 is a partial cross-sectional view showing a modification of a positioning engagement portion of a magnetic sensor that can be used with the present invention.

FIG. 5 is an end view showing an engagement portion of the magnetic sensor of FIG. 4;

FIG. 6 is a partial cross-sectional view showing a state in which an engagement portion of the magnetic sensor of FIG. 4 is arranged in a molding die.

FIG. 7 is a perspective view showing a coil bobbin of a magnetic sensor that can be used with the present invention.

FIG. 8 is a sectional view showing a flange of the coil bobbin of FIG. 7;

FIG. 9 is a side view showing a modification of the coil bobbin of the magnetic sensor that can be used with the present invention.

FIG. 10 is a perspective view showing another modification of the coil bobbin of the magnetic sensor that can be used with the present invention.

FIG. 11 is a sectional view showing a flange of the coil bobbin of FIG. 10;

FIG. 12 is a perspective view showing a sensor assembly of a magnetic sensor that can be used with the present invention.

FIG. 13 is a side view showing another modified example of the coil bobbin of the magnetic sensor that can be used with the present invention.

FIG. 14 is a cross-sectional view showing a state where lead wires are wired to the coil bobbin of FIG.

FIG. 15 is a side view showing another modification of the coil bobbin of the magnetic sensor that can be used with the present invention.

16 is a cross-sectional view showing a state in which a lead wire is wired to the coil bobbin of FIG.

FIG. 17 is a perspective view showing a sensor assembly of a magnetic sensor that can be used with the present invention.

18 is a cross-sectional view showing a state of wiring to the coil bobbin and the engagement protrusion of FIG.

FIG. 19 is a cross-sectional view showing a modification of the coil bobbin and the engagement protrusion of FIG.

FIG. 20 is a perspective view showing a terminal portion of a support of a sensor assembly of a magnetic sensor that can be used with the present invention.

21 is a sectional view showing a reference example of a magnetic sensor that can be used with the present invention using the support of FIG. 20.

FIG. 22 is a schematic diagram showing a soldering operation of a terminal portion of a sensor assembly of a magnetic sensor that can be used with the present invention.

FIG. 23 is a plan view showing a relationship between a sleeve of a support of the magnetic sensor of the present invention and a spacer.

FIG. 24 is an exploded perspective view of the sensor assembly of FIG. 23.

FIG. 25 is a sectional view of the sensor assembly of FIG. 23;

FIG. 26 is a perspective view showing a modification of a magnetic core of a magnetic sensor that can be used with the present invention.

FIG. 27 is a bottom view of the magnetic core of FIG. 26;

FIG. 28 is a perspective view showing a relationship between a magnetic core and a sleeve in FIG. 26;

FIG. 29 is a sectional view showing the relationship between the magnetic core and the sleeve of FIG. 26;

FIG. 30 is a perspective view showing a modification of the magnetic sensor that can be used with the present invention.

FIG. 31 is a cross-sectional view showing a mounting state of the magnetic sensor of FIG. 30;

FIG. 32 is a cross-sectional view showing a modification of the magnetic sensor that can be used with the present invention.

FIG. 33 is a cross-sectional view showing a modification of the magnetic sensor that can be used with the present invention.

FIG. 34 is a cross-sectional view of an embodiment using a sensor assembly having a magnetic sensor cap that can be used with the present invention.

FIG. 35 is a sectional view showing a molding die for the magnetic sensor of FIG. 34;

FIG. 36 is a perspective view showing a cap of the magnetic sensor of FIG. 34;

FIG. 37 is a perspective view showing a modification of the cap of the magnetic sensor that can be used with the present invention.

FIG. 38 is a perspective view showing a modification of the coil bobbin of the magnetic sensor that can be used with the present invention.

FIG. 39 is a sectional view of the coil bobbin of FIG. 38;

FIG. 40 is a sectional view of a conventional magnetic sensor.

FIG. 41 is a perspective view showing the conventional magnetic sensor of FIG. 40.

FIG. 42 is a cross-sectional view showing an attached state of the conventional magnetic sensor of FIG. 40.

43 is a sectional view showing a flange of a coil bobbin of the conventional magnetic sensor of FIG. 40.

44 is a cross-sectional view showing a wiring state of the sensor assembly of the conventional magnetic sensor of FIG.

FIG. 45 is a side view showing a wiring state of the sensor assembly of the conventional magnetic sensor of FIG. 40;

46 is a cross-sectional view showing a resin molding step of the conventional magnetic sensor of FIG. 40.

FIG. 47 is a cross-sectional view showing another example of the conventional magnetic sensor.

FIG. 48 is a cross-sectional view showing a resin molding step of the conventional magnetic sensor of FIG. 47.

FIG. 49 is a sectional view showing a modification of the magnetic sensor of FIG. 3;

[Explanation of symbols]

42 sensor assembly, 44 magnet, 45 magnetic core, 4
6 coil, 55 coil bobbin, 47 support, 43
Resin molded body, 56 sleeves, 51 terminals, 109,
110 Small diameter part.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F077 AA46 NN04 NN21 PP09 VV02 VV23 VV31 VV35 2G017 AA04 AB07 AC09 AD01 AD03 5E048 AB10 CB05

Claims (2)

[Claims] 1. A sensor assembly, comprising a resin molded body provided surrounding the sensor assembly to form a housing, wherein the sensor assembly includes a magnet for generating a magnetic flux and a magnet for forming a magnetic circuit. A core, a coil wound around the magnetic core to detect a change in magnetic flux passing through the magnetic core, and a support for supporting the magnet, the magnetic core, and the coil as an assembly, A coil bobbin for receiving the magnetic core, a sleeve connected to the coil bobbin at one end to receive the magnetic core and the magnet, a spacer for holding the magnetic core and the magnet in the sleeve, and the other end of the sleeve And a terminal provided on the inner peripheral surface of the sleeve for holding the spacer by pressure fitting. Magnetic sensor with a diameter part. 2. The magnetic sensor according to claim 1, wherein the small diameter portion is a projection projecting from an inner peripheral surface of the spacer.