JP2000097958A - Rotational speed detecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rotational speed detecting apparatus whose assembling property is made good and in which a sensor unit is positioned easily. SOLUTION: One each of land parts 17 to which coil terminals 5 are soldered and bonded respectively are formed on both the surface and the rear of a circuit board 13. In addition, recessed parts 17a into which the coil terminals 5 are fitted are formed in the land parts 17. The circuit board 13 is sandwiched between the coil terminals 5, and the circuit board 13 is housed in a direction (the longitudinal direction) along the longitudinal direction of a sensor head part 11 with respect to a case 10. As a result, when the tip of a sensor unit 1 is brought into contact with the inside bottom face of the sensor head part 11, the sensor unit 1 can be positioned in its insertion direction into the sensor head part 11. In addition, the positioning operation with reference to the sensor head part 11 of the sensor unit 1 is not influenced by the housing and placing state to the case of the circuit board 13, the sensor unit 1 is positioned easily, and the accuracy of a detecting characteristic can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation speed detecting device which is attached to a wheel or a transmission of an automobile to detect a rotation speed of a wheel shaft or a drive shaft.

[0002]

2. Description of the Related Art In recent years, an automobile is equipped with an anti-lock brake system, an automatic transmission, a navigation system, and the like. These devices detect the running speed of the automobile and the rotation state of wheels to perform various controls. Therefore, it has become increasingly important to accurately detect the traveling speed of a vehicle and the rotational state of wheels at low speeds. In addition, the number of rotational speed detecting devices used is increasing due to the multifunctionality and miniaturization of the automatic transmission itself, which tends to be downsized.

By the way, in order to detect the running speed of the automobile and the rotation state of the wheels as described above, generally, an optical or contact type detecting device is used in consideration of heat resistance, environmental resistance and the like. Also, a magnetic detection device is used. For example,
A rotor fixed to a rotating shaft (axle) inserted substantially at the center and rotating integrally with the rotating shaft is installed in a magnetic field, and the rotation speed of the rotating shaft (that is, traveling speed) is changed by a change in the magnetic field due to the rotation of the rotor. A rotational speed detecting device for detecting the rotational speed is used.

[0004] As the rotation speed detecting device as described above,
A substantially cylindrical metal rotor is provided with irregularities on its surface along the circumferential direction to form a gear. The rotor is fixed to a rotating shaft, and a sensor unit having a detection coil is disposed near the rotor. Then, due to the rotational motion of the rotor in a high-frequency magnetic field generated by flowing a high-frequency current through the detection coil,
The irregularities provided on the surface of the rotor along the circumferential direction change the magnetic field, and the resonance condition (such as the Q factor) of the detection coil changes, so that a detection output (detection signal) corresponding to the rotation speed of the rotor is detected. It can be taken out from both ends of the coil. The detection signal is taken out through a cable and is subjected to arithmetic processing by a control microcomputer (hereinafter abbreviated as "microcomputer") to calculate the rotation speed.

FIG. 8 shows an example of the structure of the rotation speed detecting device, and FIG. 11 shows a manufacturing process thereof. A substantially cylindrical sensor head portion 11 having a closed end protrudes from the bottom surface of the synthetic resin case 10 formed in a box shape, and mounting screws are provided on both side surfaces of the case 10 adjacent to the bottom surface. A mounting portion 12 having an insertion hole 12a through which a not shown (not shown) is inserted is provided. The sensor head 11 has a large-diameter portion 11a and a small-diameter portion 11b disposed coaxially, and communicates with the inside of the case 10 at an end on the bottom side of the case 10. 11 are accommodated in the small-diameter portion 11b and the rear end protrudes into the large-diameter portion 11a.

The sensor unit 1 includes a coil bobbin 2 made of a synthetic resin formed in a substantially cylindrical shape, a rod-shaped iron core 3 whose tip portion is exposed to the outside, and which is pressed into a hole provided substantially in the center of the coil bobbin 2. A detection coil 4 wound around the tip of the coil bobbin 2; and a coil terminal projecting rearward from the rear end of the coil bobbin 2 along the axial direction of the coil bobbin 2 and having one end connected to a terminal of the detection coil 4. 5, 5 and coil extension terminals 6 and 6, which are formed in a pin shape by a conductive spring material and are soldered to the coil terminals 5 and 5, respectively. The iron core 3 exposed from the tip of the coil bobbin 2 comes into contact with the bottom surface of the inner wall of the sensor head 11, and the unevenness of the rotor 40 described below can be detected through the bottom of the sensor head 11.

The ends of the coil extension terminals 6 and 6 have a circuit board 2 made of a printed board made of glass epoxy resin.
0 is connected by an appropriate method such as soldering. As shown in FIG. 9, a high-frequency power supply for generating a high-frequency magnetic field by supplying a high-frequency current to the detection coil 4 through the coil terminals 5 and 5 and the coil extension terminals 6 and 6 supplies a current flowing through the detection coil 4 to the circuit board 20. A circuit component 14 that constitutes a detection circuit and the like for detection is mounted.

On the other hand, three lead wires 15 for outputting the detection signal obtained by the detection circuit to the outside are inserted into the insertion holes 16a of the rubber bushing 16, and the core wires thereof are formed in the circuit board 20. It is inserted into the hole 20 a and soldered to a wiring pattern formed on the circuit board 20. A connector 21 is attached to the other end of each of the three lead wires 15 (see FIG. 11). A locking recess 16b is formed in the bushing 16, and the bushing 16 is locked by locking the locking recess 16b in a notch 10a provided on one side surface of the case 10 as shown in FIG. It is adapted to be fixed to the case 10.

Next, the manufacturing process of the above-mentioned conventional apparatus will be briefly described with reference to FIG. Bushing 16 to lead 15
And the core of the lead wire 15 is soldered to the circuit board 20 (see FIGS. 11A and 11B). The coil bobbin 2 around which the detection coil 4 is wound
The iron core 3 is press-fitted into the coil terminal 5 and the coil extension terminals 6, 6 are soldered to the coil terminals 5, 5, and the sensor unit 1 is inserted into the sensor head 11 from the opening side of the case 10 (see FIG. c) (d)). In addition, mounting part 1
A metal bush 22 is fitted into the second insertion hole 12a.

Then, the circuit board 20 is housed in the case 10. At this time, the coil extension terminals 6, 6 are inserted into the pin insertion holes 20c, 20c formed in the circuit board 20.
6, the soldering is performed, the bushing 16 is fixed to the case 10 by the notch 10a, and the projection 23 projecting from the bottom of the case 10 is inserted through the hole 20d of the circuit board 20; The circuit board 20 is fixed to the case 10 by caulking with heat (FIG. 9E).
(F)). Finally, put potting agent 2 in case 10
4 is filled and sealed to complete the rotation speed detecting device (see FIGS. 3G and 3H).

The rotational speed detecting device constructed as described above is mounted on an aluminum die-cast housing 30 of an automatic transmission, for example, as shown in FIG. That is, the sensor head 11 is inserted into the through hole 31 formed in the housing 30, and the tip of the sensor head 11 is opposed to the rotor 40 in the housing 30 in close proximity. In order to detect the rotation speed of the internal rotor 40 through the thin through-hole 31 formed in the housing 30 as described above, the sensor head 11 is elongated to some extent and the device itself is downsized.

In the above-described conventional apparatus, the circuit board 20 is housed in the case 10 after the coil bobbin 2 is inserted into the sensor head 11, and the coil extension terminals 6, 6
Are soldered to the circuit board 20, but the positioning between the tip of the detection coil 4 and the sensor head 11 is an important factor for the detection accuracy of the sensor unit 1. A support structure such as a step is provided in the case 10 to support the circuit board 20 in the case 10. However, if this is done, the position of the tip of the detection coil 4 may be determined by the support structure. 4 may not reach the bottom surface of the sensor head 11 and affect the detection accuracy.

Therefore, in the above-mentioned conventional device, after the sensor unit 1 is inserted into the sensor head 11, the coil terminals 5,
5 is electrically connected to the circuit board 20 so that the assembly can be performed with the tip of the detection coil 4 reaching the bottom surface of the sensor head unit 11. Since the sensor head 11 has an elongated shape, the coil terminals 5 and 5 of the coil bobbin 2 and the circuit board 20 are connected to the coil extension terminals 6 and 6.
To make a relay connection.

[0014]

However, in the above-mentioned conventional apparatus, the iron core 3 is press-fitted into the hole of the coil bobbin 2 and the coil extension terminals 6 and 6 are soldered to the coil terminals 5 and 5. Since the sensor unit 1 is inserted into the circuit board 11, the soldering of the lead wire 15 to the circuit board 20 and the soldering of the coil extension terminals 6, 6 to the circuit board 20 cannot be performed at the same time. The disadvantage is that there is a disadvantage. Further, since the axial direction of the coil bobbin 2 is arranged so as to substantially coincide with the normal direction of the circuit board 20, terminal components (coil extension terminals 6, 6) for relay connection between the coil terminals 5, 5 and the circuit board 20 are provided. )
Is required.

Further, the case 1 is provided by the potting agent 24.
It is necessary to pour the potting agent 24 up to the back side of the circuit board 20 and the sensor unit 1 when sealing the inside of the circuit board 20, but the circuit board 20 is stored parallel (horizontally) to the opening face of the case 10. In this case, the gap through which the high-viscosity potting agent 24 flows to the sensor head portion 11 becomes narrow, and the escape of air becomes poor, so that the sealing operation takes time and becomes difficult. Moreover, if air remains in the case 10, it is considered that the detection characteristics are affected by expansion / contraction of the air due to a temperature change.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a rotation speed detecting device which has good assemblability and facilitates positioning of a sensor unit.

[0017]

According to a first aspect of the present invention, there is provided a detection coil including a detection coil and a coil bobbin around which the detection coil is wound, and which detects a change in a magnetic field accompanying rotation of a rotating body. A sensor unit for detecting, a circuit unit for generating a high-frequency magnetic field by driving the detection coil and extracting a change in the high-frequency magnetic field accompanying the rotation of the rotating body as an electric signal, and a circuit component constituting the circuit unit are mounted. A circuit board, a case in which the circuit board is mounted, a sensor head protruding from the case and accommodating the sensor unit therein, and a detection coil protruding from the coil bobbin and having one end each of the detection coil. A pair of coil terminals connected to the terminals of the circuit board, and the other end of each coil terminal sandwiches the circuit board between the pair of coil terminals. To characterized by comprising connecting each without positioning with respect to the sensor head of the sensor unit by sandwiching the circuit board by the coil bobbin is affected by OsameSo state to the circuit board case,
The above positioning can be easily performed, and the balance of assembly is improved. Also, the coil terminals can be directly connected to the circuit board, eliminating the need for conventional coil terminal extension parts, and connecting the coil terminals to the circuit board in other operations, such as lead wires to the circuit board. Can be performed at the same time as the connection, so that the assemblability can be improved. In addition, since the longitudinal direction of the coil bobbin can be made substantially coincident with the plane direction of the circuit board, the flow of the sealing potting agent is blocked by the circuit board with the sensor unit and the circuit board mounted in the case. Thus, the workability of the sealing with the potting agent can be improved, and the occurrence of problems due to air remaining inside the potting agent can be reduced.

According to a second aspect of the present invention, in the first aspect of the present invention, a concave portion is provided on each of the front and back surfaces of the circuit board, in which a connection portion of the coil terminal is fitted. Can be positioned and temporarily fixed in the longitudinal direction of the coil bobbin.

According to a third aspect of the present invention, there is provided the circuit according to the second aspect, wherein the coil terminal is formed in a substantially hook shape and the recess is formed in a substantially hook shape matching the shape of the coil terminal. The positioning and temporary fixing of the coil bobbin in the longitudinal direction of the coil terminal and the direction orthogonal to the longitudinal direction with respect to the substrate can be performed.

[0020]

(Embodiment 1) Embodiment 1 of the present invention will be described in detail with reference to FIGS. However, portions common to the conventional example are denoted by the same reference numerals, and illustration and description are omitted.

A circuit board 13 made of a printed circuit board formed in a strip shape has circuit components 14 surface-mounted on both front and back surfaces. An insertion hole 1 through which a core wire 15a of a lead wire 15 is inserted is provided at one end of the circuit board 14 facing the longitudinal direction.
The core wire of the lead wire 15 is soldered to a wiring pattern formed on the mounting surface of the circuit board 13 in a state of being inserted into the insertion hole 13a.

On the other hand, land portions 17, 17 to which the coil terminals 5, 5 are respectively soldered are provided on the front and back surfaces, respectively, at the other end of the circuit board 13 opposed in the longitudinal direction.
Further, as shown in FIG. 4, the lands 17 have recesses 17a into which the coil terminals 5 are fitted.

The coil bobbin 2 is formed in a substantially cylindrical shape with an insulating material such as a synthetic resin. A detection coil 4 is wound around the tip of the coil bobbin 2, and an iron core 3 made of a ferrite material is press-fitted so as to partially protrude. From the rear end, a pair of substantially cylindrical coil terminals 5 and 5 project rearward along the axial direction of the coil bobbin 2. Note that the land portions 17 and 1
3 to secure a solder joint area between the sensor coil 7 and the detection coil 4.
As shown in FIG.
It is wound around.

Then, one of the coil terminals 5 is connected to the circuit board 1.
3 The other coil terminal 5 is fitted into the concave portion 17a of the land portion 17 on the front surface side and the concave portion 1 of the land portion 17 on the rear surface side.
7a, the circuit board 13 is positioned and temporarily fixed in the short width direction (X direction in FIG. 3). In this state, the coil terminals 5, 5 are soldered to the lands 17, 17. As shown in FIGS. 4 and 5, the circuit board 13 is held between the pair of coil terminals 5 and 5.

After soldering the coil terminals 5, 5 and the lead wires 15 to the circuit board 13, the sensor unit 1 and the circuit board 13 are inserted into the sensor head 11 from the sensor unit 1 as shown in FIG. Then, the rear end of the sensor unit 1 including the coil terminals 5 and 5 has the large diameter portion 11.
The sensor unit 1 is accommodated in the small-diameter portion 11b of the sensor head 11 so as to protrude toward the sensor unit 11 and a gap g is formed between the leading edge of the circuit board 13 and the inner bottom surface of the large-diameter portion 11a. (The tip of the iron core 3 protruding from the coil bobbin 2) abuts on the inner bottom surface of the sensor head 11 so that the sensor unit 1 can be positioned with respect to the sensor head 11. A pair of guide ribs 11c are provided on the inner peripheral surface of the large-diameter portion 11a so as to abut on the mounting surface of the circuit board 13 to guide the insertion of the circuit board 13 into the sensor head 11 (FIG. 1). reference).

As described above, in the present embodiment, the circuit board 13 is sandwiched between the pair of coil terminals 5 and 5 provided in the sensor unit 1, and the circuit board 13 is moved in the longitudinal direction of the sensor head 11 with respect to the case 10. The sensor head 1 is housed in the direction (vertical direction)
By contacting the tip of the sensor unit 1 with the inner bottom surface of the sensor unit 1, the sensor unit 1 can be positioned in the direction of insertion into the sensor head unit 11. Since it is not necessary to make the sensor unit 10 abut, the positioning of the sensor unit 1 with respect to the sensor head unit 11 is not affected by the state of the circuit board 13 mounted in the case 10 and the positioning is facilitated. There is an advantage that accuracy can be improved.

Further, the lead wire 15 for the circuit board 13
Can be performed at the same time as the coil terminals 5 and 5, so that assemblability and assembling efficiency can be improved as compared with the conventional example. Moreover, since the circuit board 13 is supported by the sensor unit 1 by being sandwiched between the coil terminals 5, 5, the circuit board 1 is placed on the center axis of the coil bobbin 2.
3, the coil terminals 5, 5 can be directly connected to the circuit board 13.
Also, there is an advantage that the coil extension terminals 6 and 6 as in the conventional example become unnecessary by soldering. Case 1
0 and a sufficient gap is formed between the inner wall of the sensor head 11 and the circuit board 13, so that the flow of the potting agent for sealing is not obstructed by the circuit board 13 and the workability of the sealing with the potting agent. And the occurrence of problems due to air remaining in the potting agent can be reduced.

(Embodiment 2) Embodiment 2 of the present invention is shown in FIG.
This will be described in detail with reference to FIG. However, since the basic configuration of this embodiment is the same as that of the first embodiment, the common parts are denoted by the same reference numerals, and illustration and description thereof will be omitted. Only the features that are characteristic of the present embodiment will be described. .

In this embodiment, the coil terminals 5, 5 projecting from the coil bobbin 2 are formed in a substantially hook shape (substantially L-shape), and the shape of the concave portion 17a 'provided in the land portion 17' of the circuit board 13 is formed. Is formed in a substantially hook shape (substantially L-shape) that matches the shape of the coil terminal 5.

The coil terminals 5, 5 are bent at substantially right angles at their leading ends to form a substantially L-shape, and the end of the detection coil 4 is wound as in the first embodiment.

Thus, the coil terminals 5, 5 are inserted into the recesses 17a '.
In the same manner as in the first embodiment, not only can the coil terminals 5 and 5 be positioned in the short width direction of the circuit board 13 (X direction in FIG. 6) and prevented from coming off, but also in the longitudinal direction of the circuit board 13 (FIG. (In the Y direction) and the coil terminals 5, 5 can be positioned and prevented from coming off, and the coil terminals 5, 5 can be temporarily fixed to the circuit board 13.

According to this embodiment, the circuit board 13
Since the coil terminals 5, 5 can be positioned and prevented from coming off not only in the short width direction but also in the longitudinal direction, there is an advantage that the detection accuracy can be further improved as compared with the first embodiment.

[0033]

According to a first aspect of the present invention, there is provided a sensor unit including a detection coil and a coil bobbin around which the detection coil is wound, the sensor unit detecting a change in a magnetic field accompanying rotation of the rotating body.
A circuit unit that drives the detection coil to generate a high-frequency magnetic field and extracts a change in the high-frequency magnetic field accompanying the rotation of the rotating body as an electric signal; a circuit board on which circuit components configuring the circuit unit are mounted; A case in which the circuit board is mounted, a sensor head protruding from the case and housing the sensor unit therein, and one end protruding from the coil bobbin and connected to a terminal of the detection coil, respectively. A pair of coil terminals is provided, and the circuit board is sandwiched between the pair of coil terminals, and the other end of each coil terminal is connected to each of the front and back surfaces of the circuit board, so that the circuit board is sandwiched by coil bobbins. As a result, the positioning of the sensor unit with respect to the sensor head is not affected by the state of mounting the circuit board to the case,
There is an effect that the above-mentioned positioning can be performed easily and the balance of assembly is improved. Also, the coil terminals can be directly connected to the circuit board, eliminating the need for conventional coil terminal extension parts, and connecting the coil terminals to the circuit board in other operations, such as lead wires to the circuit board. Can be performed at the same time as the connection, so that there is an effect that assemblability can be improved. In addition, since the longitudinal direction of the coil bobbin can be made substantially coincident with the plane direction of the circuit board, the flow of the sealing potting agent is blocked by the circuit board with the sensor unit and the circuit board mounted in the case. Will not be
There is an effect that the workability of the sealing with the potting agent can be improved, and the occurrence of problems due to air remaining inside the potting agent can be reduced.

According to a second aspect of the present invention, since a concave portion into which the connection portion of the coil terminal is fitted is provided on both the front and back surfaces of the circuit board, the positioning of the coil bobbin in the longitudinal direction of the coil terminal with respect to the circuit board and the provision of the coil bobbin are performed. There is an effect that fixing can be performed.

According to a third aspect of the present invention, the coil terminal is formed in a substantially hook shape and the recess is formed in a substantially hook shape matching the shape of the coil terminal. There is an effect that the coil bobbin can be positioned and temporarily fixed in a direction orthogonal to the longitudinal direction.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a first embodiment.

FIG. 2 is an exploded perspective view of a main part of the same.

FIG. 3 is a partially omitted plan view showing the sensor unit and the circuit board in the same.

FIG. 4 is a side sectional view of a main part of the above.

FIG. 5 is a side view in which a main part of the above is partially omitted.

FIG. 6 is a partially omitted plan view showing a sensor unit and a circuit board according to a second embodiment.

FIG. 7 is a side view in which main parts of the above are partially omitted.

FIG. 8 is an exploded side view of a conventional example.

FIG. 9 is a front view of the circuit board in the above.

FIG. 10 is a side view of the coil extension terminal in the above.

FIGS. 11 (a) to 11 (h) are views showing manufacturing steps of the above.

FIG. 12 is a partially omitted side sectional view showing the use state of the above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sensor unit 2 Coil bobbin 4 Detection coil 5 Coil terminal 10 Case 11 Sensor head part 13 Circuit board 17 Land part 17a Depression

Claims (3)

[Claims] 1. A sensor unit having a detection coil and a coil bobbin around which the detection coil is wound, the sensor unit detecting a change in a magnetic field accompanying rotation of a rotating body, and driving the detection coil to generate a high-frequency magnetic field. A circuit section for extracting a change in a high-frequency magnetic field accompanying the rotation of the rotating body as an electric signal, a circuit board on which circuit components constituting the circuit section are mounted, a case in which the circuit board is mounted, and A sensor head protruding and housing the sensor unit therein; and a pair of coil terminals protruding from the coil bobbin and having one end connected to a terminal of the detection coil. A rotation speed detecting device comprising the circuit board interposed therebetween and the other end of each coil terminal connected to each of the front and back surfaces of the circuit board. 2. The rotation speed detecting device according to claim 1, wherein a concave portion into which a connection portion of the coil terminal is fitted is provided on both front and back surfaces of the circuit board. 3. The rotation speed detecting device according to claim 2, wherein the coil terminal is formed in a substantially hook shape, and the concave portion is formed in a substantially hook shape matching the shape of the coil terminal.