JP7095643B2 - Rotation speed sensor - Google Patents

Description

The present invention relates to a sensor for detecting the rotation speed of an object, and more particularly to a sensor suitable for detecting the rotation speed of a wheel.

Today, vehicles such as automobiles or motorcycles are equipped with various sensors, and one of the sensors for these vehicles is a rotation speed sensor. The rotation speed sensor is mounted on the vehicle, for example, for the purpose of detecting the rotation speed of the wheels. A rotation speed sensor mounted on a vehicle for this purpose is generally called a wheel speed sensor. The rotation speed sensor as a wheel speed sensor is mounted on a vehicle as one of components such as an anti-lock braking system (ABS system) for preventing wheel lock or a traction control system for preventing wheel slippage.

The wheel speed sensor as described above has a cable constituting a signal transmission path, a sensor head provided on one end side of the cable, and a connector provided on the other end side of the cable. The sensor head has a built-in magnetic sensor IC (hereinafter referred to as “sensor IC”) including a detection element such as a Hall element or a magnetoresistive effect element. The sensor head is located in the vicinity of a magnet encoder or rotor that rotates with the wheel. The sensor IC (detection element) built into the sensor head detects the magnetic field fluctuation around the sensor head that occurs with the rotation of the magnet encoder or rotor, and an electric signal corresponding to this magnetic field fluctuation (wheel rotation speed). Is output. The electric signal output from the sensor IC is transmitted by a cable and input to a control unit or a control device via a connector.

Conventionally, one sensor IC is built in the sensor head. On the other hand, with the development of an automatic driving system or a driving support system, improvement of reliability and stability of a rotation speed sensor including a wheel speed sensor is required. Therefore, it is considered to increase the number of sensor ICs built in the sensor head to improve the reliability and stability of the rotational speed sensor. That is, redundancy of the rotation speed sensor is being studied.

Patent Document 1 (Japanese Unexamined Patent Publication No. 2017-96828) describes a wheel speed sensor equipped with two detection element units. Here, the two wires connected to the detection element section are combined into one sheathed wire, and the sheathed wires connected to each of the two detection element section sensors are combined into one rubber tube, for a total of four. The wires are put together in one.

JP-A-2017-96828

When two sensor ICs are built in the sensor head due to the redundancy of the rotation speed sensor, two wirings (Vcc wiring and GND wiring for supplying sensor power supply) connected to each sensor IC, that is, a total of four wirings are one. It is conceivable to put them together. When the four wirings are combined into one in the sensor head which is a resin molded body, when a plurality of the wirings are entangled with each other, the resin constituting the sensor head is not filled between the wirings, and the rotation speed sensor is used. There is a problem of reduced reliability.

Other issues and novel features will become apparent from the description and accompanying drawings herein.

A brief description of typical embodiments disclosed in the present application is as follows.

The rotational speed sensor according to one embodiment has a sensor head, a first sensor IC and a second sensor IC embedded in the sensor head, and a cable whose end is located in the sensor head. There is. In the cable, the first insulated wire and the second insulated wire connected to the first sensor IC, and the third insulated wire and the fourth insulated wire connected to the second sensor IC form one stranded wire. Is what you are doing. In the cross section of the cable, the first insulated wire and the second insulated wire are arranged in the first direction, the third insulated wire and the fourth insulated wire are arranged in the first direction, and the first insulated wire or the second insulated wire and the third insulated wire are arranged. The electric wires are arranged in a second direction intersecting with the first direction.

According to the present invention, the reliability of the rotational speed sensor can be improved.

It is a schematic diagram which shows the structure of the rotation speed sensor which concerns on Embodiment 1. FIG. It is a perspective view of the sensor head shown in FIG. It is a perspective view of the sensor head shown in FIG. FIG. 2 is a cross-sectional view taken along the line AA of the sensor head shown in FIG. It is a perspective view which shows the connection state of the sensor IC and a cable in the sensor head shown in FIG. It is a top view which shows the connection state of the sensor IC and a cable in the sensor head shown in FIG. It is a bottom view which shows the connection state of a sensor IC and a cable in the sensor head shown in FIG. It is sectional drawing in the BB line of the cable shown in FIG. It is a schematic diagram which shows the connection state of the sensor IC and a cable in the sensor head shown in FIG. It is sectional drawing of the mold used in the manufacturing process of the rotational speed sensor which concerns on Embodiment 1. FIG. It is a perspective view which shows the sensor head which constitutes the rotational speed sensor which concerns on Embodiment 1. FIG. It is a perspective view which shows the connection state of the sensor IC and a cable in the sensor head shown in FIG. FIG. 11 is a bottom view showing a connection state between the sensor IC and the cable in the sensor head shown in FIG. FIG. 3 is a cross-sectional view taken along the line CC of the cable shown in FIG. It is a schematic diagram which shows the connection state of the sensor IC and a cable in the sensor head shown in FIG. It is a schematic diagram which shows the connection state of the sensor IC which constitutes the rotational speed sensor which concerns on a comparative example, and a cable.

(Embodiment 1)
Hereinafter, an example of the embodiment of the rotational speed sensor of the present invention will be described in detail with reference to the drawings. The rotation speed sensor according to the present embodiment is a wheel speed sensor mounted on a vehicle as one of the components of the ABS system.

<Structure of rotational speed sensor of this embodiment>
2 and 3 used in the following description are perspective views showing the sensor head 2 from different directions. However, in FIG. 3, the cable 3, the sensors ICs 41 and 42, the terminals between them, the insulated wire, and the like are transmitted and shown.

As shown in FIG. 1, the wheel speed sensor 1A, which is the rotation speed sensor according to the present embodiment, has a sensor head 2, a cable 3, and a connector 4. The sensor head 2 is arranged in the vicinity of a magnet encoder 5 that rotates together with a wheel (not shown). Specifically, the sensor head 2 is fixed to the vehicle body (hub, knuckle, suspension, etc.) so that the positional relationship with the magnet encoder 5 has a predetermined positional relationship. N-pole portions and S-pole portions are alternately provided on the peripheral edge of the magnet encoder 5 along the rotation direction of the magnet encoder 5. Therefore, when the magnet encoder 5 rotates with the rotation of the wheel, a magnetic field fluctuation occurs around the sensor head 2. The sensor head 2 has a built-in magnetic sensor IC (sensor IC) that detects a magnetic field fluctuation and outputs an electric signal corresponding to the magnetic field fluctuation. Further, the sensor head 2 and the connector 4 are connected via a single cable 3. The electric signal output from the sensor IC built in the sensor head 2 is transmitted to the connector 4 via the cable 3 and input to the connection destination of the connector 4. The connector 4 is connected to, for example, a control unit or control device of an ABS system, or a control unit or control device that collectively controls various systems including the ABS system.

As shown in FIGS. 1, 2 and 3, the sensor head 2 includes a flange portion 10, a sensor holding portion 20 provided on one side of the flange portion 10, and a cable provided on the other side of the flange portion 10. The holding portion 30 and the like are included. The flange portion 10, the sensor holding portion 20, and the cable holding portion 30 are integrally molded with resin. In other words, each of the flange portion 10, the sensor holding portion 20, and the cable holding portion 30 is a part of the injection-molded resin molded body.

As shown in FIG. 1, the flange portion 10 has a front surface 11a and a back surface 11b parallel to each other, and has a substantially plate-like appearance as a whole. As shown in FIGS. 1, 2 and 3, the flange portion 10 is provided with a through hole 12 through which a fixing member (for example, a bolt) for fixing the sensor head 2 at a predetermined position is inserted. The through hole 12 penetrates the flange portion 10 in the thickness direction of the flange portion 10, one end of the through hole 12 opens at the front surface 11a of the flange portion 10, and the other end of the through hole 12 is the back surface of the flange portion 10. It is open at 11b. As shown in FIG. 2, an annular reinforcing member 13 is provided inside the through hole 12. The reinforcing member 13 in the present embodiment is made of metal, but the reinforcing member 13 is not limited to the metal, and may be made of, for example, a resin.

As shown in FIGS. 1, 2 and 3, the sensor holding portion 20 and the cable holding portion 30 generally have a tubular appearance as a whole. More specifically, the sensor holding portion 20 projects forward from the front surface 11a of the flange portion 10, and the root side has a substantially cylindrical appearance and the tip side has a substantially square tubular appearance. On the other hand, the cable holding portion 30 projects from the back surface 11b of the flange portion 10 to the rear opposite to the front, and has a substantially cylindrical appearance over the entire length.

Here, the thickness direction of the flange portion 10 is defined as the “front-back direction”, and the height direction (longitudinal direction) of the flange portion 10 is defined as the “vertical direction”. Further, the direction orthogonal to both the front-back direction and the up-down direction is defined as the "left-right direction". Further, regarding the front-rear direction, the protruding direction (first direction) of the sensor holding portion 20 with respect to the flange portion 10 is "forward", and the protruding direction (second direction) of the cable holding portion 30 with respect to the flange portion 10 is "rear". .. In the vertical direction, the side where the through hole 12 is provided is referred to as "downward", and the side opposite to the side where the through hole 12 is provided is referred to as "upward". Further, the root side of the sensor holding portion 20 having a substantially cylindrical appearance is called a "base end portion 20a", and the tip end side of the sensor holding portion 20 having a substantially square cylindrical appearance is referred to as a "tip portion 20b". May be called. In other words, the portion exhibiting a substantially cylindrical appearance is the base end portion 20a, and the portion exhibiting a substantially square tubular appearance is the tip end portion 20b.

As shown in FIGS. 3 and 4, the sensor head 2 contains a plurality of sensor ICs 40 including a detection element for detecting magnetic field fluctuations. In other words, the sensor head 2 contains a plurality of sensor ICs 40 that output an electric signal corresponding to the fluctuation of the magnetic field. In the present embodiment, a total of two sensor ICs (first sensor IC) 41 and sensor IC (second sensor IC) 42 are embedded in the tip of the sensor holding portion 20. More specifically, the two sensors ICs 41 and 42 are embedded in the vicinity of the end surface of the tip portion 20b of the sensor holding portion 20.

Each of the sensors ICs 41 and 42 includes magnetoresistive elements 41c and 42c as detection elements. The magnetoresistive effect elements 41c and 42c in the present embodiment are giant magnetoresistive effect elements (GMR (Giant Magneto Resistive effect) elements). The sensors IC 41 and 42 are stacked one above the other with both detection surfaces facing upward. In the following description, the sensor IC 41 may be referred to as an "upper sensor IC 41" and the sensor IC 42 may be referred to as a "lower sensor IC 42" for distinction. However, such a distinction is merely a distinction for convenience of explanation. On the other hand, the sensors IC 41 and 42 may be collectively referred to as "sensor IC 40".

As shown in FIG. 4, the tip of the cable 3 is connected to the sensor head 2. Specifically, the end of the cable 3 is covered with the cable holding portion 30. That is, the end portion of the cable 3 is molded into the cable holding portion 30. As a result, the cable 3 extends rearward from the end surface 30a of the cable holding portion 30. FIG. 4 is a cross-sectional view taken along the line AA of the sensor head shown in FIG. 2, but the four insulated wires passing through the cable 3 are not shown in cross section but in the side view from the left.

As shown in FIGS. 4 to 7, the cable 3 is a multi-core cable including four core wires 50. More specifically, the cable 3 is a multi-core cable including a pair of core wires 50 connected to the upper sensor IC 41 and another pair of core wires 50 connected to the lower sensor IC 42. FIG. 6 is a plan view of the structure shown in FIG. 5 as viewed from above, and FIG. 7 is a plan view and bottom view of the structure shown in FIG. 5 as viewed from below.

As shown in FIG. 5, each core wire 50 is covered with an insulator (insulating film) 55. Further, each core wire 50 covered with the insulator 55 is collectively covered with a sheath (skin, insulator) 56 in a twisted state (see FIG. 4). Specifically, the insulator 55 that covers the core wire 51a and the core wire 51a constitutes an insulated wire (first insulated wire) 61a, and the insulator 55 that covers the core wire 51b and the core wire 51b is an insulated wire (second insulating wire). Wire) 61b (see FIGS. 5 and 6). Further, the insulator 55 that covers the core wire 52a and the core wire 52a constitutes an insulated wire (third insulated wire) 62a, and the insulator 55 that covers the core wire 52b and the core wire 52b is an insulated wire (fourth insulated wire) 62b. (See FIGS. 5 and 7).

That is, the cable 3 has four insulated wires 61a, 61b, 62a and 62b twisted together, and a sheath 56 that collectively covers the four insulated wires 61a, 61b, 62a and 62b and puts them together. It is a core cable. The core wire 50 in the present embodiment is a stranded wire composed of a plurality of copper alloy wires containing tin. The insulator 55 is made of flame-retardant cross-linked polyethylene, and the sheath 56 is made of thermoplastic urethane. Of course, the materials of the core wire 50, the insulator 55, and the sheath 56 are not limited to the above materials.

As shown in FIGS. 6 and 7, the four core wires 50 included in the cable 3 are electrically connected to a predetermined sensor IC 40. Specifically, as shown in FIG. 6, the two core wires 51a and 51b are connected to the upper sensor IC 41, and as shown in FIG. 7, the other two core wires 52a and 52b are connected to the lower sensor IC 42. There is. More specifically, the core wire 51a is connected to the input terminal (first terminal) 41a of the upper sensor IC 41, and the core wire 51b is connected to the output terminal (second terminal) 41b of the upper sensor IC 41. Similarly, the core wire 52a is connected to the input terminal (third terminal) 42a of the lower sensor IC 42, and the core wire 52b is connected to the output terminal (fourth terminal) 42b of the lower sensor IC 42.

Each of the input terminals 41a and 42a and the output terminals 41b and 42b has a strip shape. Then, the core wire 51a is resistance welded to the input terminal 41a, and the core wire 51b is resistance welded to the output terminal 41b. Further, the core wire 52a is resistance welded to the input terminal 42a, and the core wire 52b is resistance welded to the output terminal 42b. In the following description, the input terminal 41a and the output terminal 41b may be collectively referred to as "terminal 57", and the input terminal 42a and the output terminal 42b may be collectively referred to as "terminal 58".

The end of the sheath 56, the core wire 50, the terminal 57, the terminal 58, and the main body of the sensor IC 40 shown in FIGS. 4, 6 and 7 are held by the holder 60. In other words, the sensor IC 40 including the end of the sheath 56, the core wire 50, the terminal 57 and the terminal 58 is built in the sensor head 2 shown in FIG. 2 while being held by the holder 60. In FIGS. 6 and 7, the specific shapes of the plate-shaped separators 66 and 67 and the side wall portions 64 and 65 constituting the holder 60 are not shown, and are shown by alternate long and short dash lines.

The holder 60 has a pair of side wall portions 64, 65 facing each other and a support plate 63 straddling the side wall portions 64, 65. The upper sensor IC 41 (see FIGS. 5 and 6) including the core wires 51a and 51b and the terminal 57 is arranged on the upper surface side of the support plate 63. On the other hand, the lower sensor IC 42 (see FIGS. 5 and 7) including the core wires 52a and 52b and the terminal 58 is arranged on the lower surface side of the support plate 63.

A plate-shaped separator 66 interposed between the core wires 51a and 51b is provided. In other words, the separator 66 is a partition wall interposed between a pair of core wires 51a and 51b connected to the same sensor IC (upper sensor IC 41). A separator 67 similar to the separator 66 is projected on the lower surface of the support plate 63. The separator 67 is also a partition wall interposed between the pair of core wires 52a and 52b connected to the same sensor IC (lower sensor IC 42).

As shown in FIG. 6, the separator 66 extends forward beyond the ends of the core wires 51a and 51b, and is interposed between the input terminal 41a and the output terminal 41b. As shown in FIG. 7, the separator 67 extends forward beyond the ends of the core wires 52a and 52b and is interposed between the input terminal 42a and the output terminal 42b. As a result, the core wire 51a and the input terminal 41a are arranged between the separator 66 and the upper portion of the side wall portion 64, and the core wire 51b and the output terminal 41b are arranged between the separator 66 and the upper portion of the side wall portion 65. (See FIG. 6). Further, the core wire 52a and the input terminal 42a are arranged between the separator 67 and the lower portion of the side wall portion 64, and the core wire 52b and the output terminal 42b are arranged between the separator 67 and the lower portion of the side wall portion 65 ( See FIG. 7).

The separator 66 shown in FIG. 6 serves to position the core wires 51a and 51b, the input terminal 41a and the output terminal 41b at predetermined positions on the holder 60, and also short-circuits the core wire 51a and the core wire 51b and the input terminal 41a. It plays a role of preventing a short circuit with the output terminal 41b. The separator 67 shown in FIG. 7 serves to position the core wires 52a and 52b, the input terminal 42a and the output terminal 42b at predetermined positions on the holder 60, and also short-circuits the core wire 52a and the core wire 52b and the input terminal 42a. It plays a role of preventing a short circuit with the output terminal 42b.

As shown in FIG. 8, four insulated wires 61a, 61b, 62a and 62b pass through the sheath 56 constituting the cable 3. That is, the cable 3 is a bundle of four insulated wires 61a, 61b, 62a and 62b.

The cross section of the cable 3 as shown in FIG. 8 is a cross section along the lateral direction (diameter direction) of the cable 3 and is a cross section orthogonal to the extending direction of the cable 3. In the cross section, the four insulated wires 61a, 61b, 62a and 62b are located, for example, at the four corners of a regular quadrangle. That is, the insulated wires 61a, 61b, 62a and 62b are arranged in a matrix. Here, in the cross section, the insulated wires 61a and 61b are aligned with each other in the first direction, and the insulated wires 62b and 62a are aligned with each other in the first direction. Further, in the cross section, the insulated wires 61a and 62b are aligned with each other in the second direction, and the insulated wires 61b and 62a are aligned with each other in the second direction. The first direction and the second direction are directions along the cross section and intersect with each other. The first direction and the second direction are, for example, orthogonal to each other. In FIG. 8, the four insulated wires 61a, 61b, 62a and 62b are separated from each other in the sheath 56, but the adjacent insulated wires may be in contact with each other. That is, the insulated wire 61a is in contact with the insulated wires 61b and 62b, the insulated wire 61b is in contact with the insulated wires 61a and 62a, the insulated wire 62a is in contact with the insulated wires 61b and 62b, and the insulated wire 62b is insulated. It may be in contact with the electric wires 61a and 62a. Further, each of the four insulated wires 61a, 61b, 62a and 62b may be located at the four corners of a parallelogram (for example, a rhombus) instead of a regular quadrangle, for example.

FIG. 9 shows a schematic view of a state in which the sensors ICs 41 and 42 in the sensor head 2 (see FIG. 2) are not overlapped in the vertical direction and are arranged side by side (expanded state). The upper sensor IC 41 has a layout close to a rectangle, for example, in a plan view. The plan view referred to here means to see the upper sensor IC 41 from a direction (upper side) orthogonal to the detection surface (main surface, first detection surface) of the sensor IC. The input terminal 41a and the output terminal 41b extend from one side of the upper sensor IC 41 having a substantially rectangular shape in a plan view, and are aligned with each other along the one side. The lower sensor IC 42 is the same element having the same function and structure as the upper sensor IC 41. Therefore, the input terminal 42a and the output terminal 42b extend from one side of the substantially rectangular lower sensor IC 42 in a plan view, and are aligned with each other along the one side.

In FIG. 9, the detection surface of the upper sensor IC 41 faces upward, and the detection surface of the lower sensor IC 42 faces downward. That is, in FIG. 9, the back surface (first back surface) on the opposite side of the detection surface (main surface, first detection surface) of the upper sensor IC 41 faces downward, and the detection surface (main surface, second detection surface) of the lower sensor IC 42 faces downward. The back surface (second back surface) on the opposite side of) is facing upward. In the process of connecting the core wire 50 to each of the sensors IC 41 and 42, the sensors IC 41 and 42 are oriented so that the main surface (upper surface) of the two upper sensor IC 41s and the back surface (lower surface) of the lower sensor IC 42 face upward. It is conceivable to weld the core wire 50 to the terminals 57 and 58 in that state. After that, by changing the directions of the sensors ICs 41 and 42 by 90 degrees in opposite directions, the sensors ICs 41 and 42 can be overlapped with the detection surfaces facing the same direction. However, in this connection step, the detection surfaces of the sensors IC 41 and 42 may face either upward or downward.

In each drawing of the present application, the sensors IC 41 and 42 having a substantially rectangular planar shape are diagonally hung on one corner of each of the sensors IC 41 and 42 so that the orientations of the detection surface and the back surface of the sensors IC 41 and 42 can be easily understood. The part is shown. On the other hand, the planar shape of the sensor IC 41 may be symmetrical in the direction in which the input terminals 41a and the output terminals 41b are lined up. The same applies to the sensor IC 42.

Further, the detection surfaces of the sensors IC 41 and 42 do not have to face completely in the same direction. In other words, the detection surfaces of the sensors IC 41 and 42 do not have to be completely parallel.

The input terminal 41a is a power supply voltage terminal for supplying a power supply voltage (Vcc) to the upper sensor IC 41, and the insulated wire 61a including the core wire 51a connected to the input terminal 41a is a power supply wiring (plus wiring). Further, the output terminal 41b is a ground terminal for connecting the upper sensor IC 41 to the ground potential (GND), and the insulated wire 61b including the core wire 51b connected to the output terminal 41b is a ground wire (minus wiring). ..

Similarly, the input terminal 42a is a power supply voltage terminal for supplying a power supply voltage (Vcc) to the lower sensor IC 42, and the insulated wire 62a including the core wire 52a connected to the input terminal 42a is a power supply wiring (plus wiring). ). Further, the output terminal 42b is a ground terminal for connecting the lower sensor IC 42 to the ground potential (GND), and the insulated wire 62b including the core wire 52b connected to the output terminal 42b is a ground wire (minus wiring). be.

As shown in FIG. 5, the sensors ICs 41 and 42 and the cable connected to each other in this way are vertically stacked with both detection surfaces facing upward. This is to give each of the sensors IC 41 and 42 the same function. One of the sensors ICs 41 and 42 is a spare element provided to prevent the rotational speed sensor from losing its function and not operating normally when, for example, the other fails due to a failure or the like. .. Therefore, the detection surfaces of the sensors IC 41 and 42 need to face in the same direction. In other words, the back surface of the upper sensor IC 41 and the detection surface of the lower sensor IC 42 face each other.

If the detection surfaces of the sensors IC 41 and 42 face different directions from each other, the rotation direction of the wheel detected by the sensor IC 41 and the rotation direction of the wheel detected by the sensor IC 41 are different from each other. Therefore, one of the sensor ICs cannot be used as a spare. In the normal state, the sensors IC 41 and 42 operate at the same time. That is, although the detection surface of the sensor IC and the back surface are separately expressed here, it can be said that the back surface is also a detection surface capable of detecting the rotational speed of the wheel. However, when the back surface faces the wheel side, reverse rotation is detected unlike the case where the detection surface faces the wheel side.

As described above, the same element is used for each of the sensors IC 41 and 42. That is, the sensor IC 41 and the sensor IC 42 have the same positional relationship between the input terminal and the output terminal with respect to the detection surface (main surface). Specifically, the output terminals 41b are arranged on the left side of the input terminal 41a, and the directions along the directions in which the input terminals 41a and the output terminals 41b are arranged and the extending directions of the input terminals 41a and the output terminals 41b are respectively. In the direction orthogonal to the above (vertical direction), the main surface (detection surface) is located on the upper side of the upper sensor IC 41, and the back surface is located on the lower side. In that case, the configuration of the lower sensor IC 42 is the same. That is, the output terminals 42b are arranged on the left side of the input terminal 42a, and are orthogonal to the planes along the directions in which the input terminals 42a and the output terminals 42b are arranged and the extending directions of the input terminals 42a and the output terminals 42b. In the direction (vertical direction), the main surface (detection surface) is located on the upper side of the lower sensor IC 42, and the back surface is located on the lower side.

The above positional relationship may be changed as appropriate. For example, the positional relationship between the input terminal 41a and the output terminal 41b may be reversed. However, even in that case, the positional relationship between the input terminal and the output terminal with respect to the detection surface (main surface) of each of the sensors IC 41 and 42 is the same. That is, the main surface (detection surface) on the upper side of the upper sensor IC 41 and the main surface (detection surface) of the lower sensor IC 42 face each other in the same direction, and the input terminals 41a and 42a overlap each other in a plan view and are output terminals. 41b and 42b overlap each other in a plan view.

At this time, among the insulated wires 61a, 61b, 62a and 62b arranged in a matrix in the cross section of the cable 3, the insulated wires 61a and 61b are arranged in the row direction (or column direction) (see FIG. 8). At the end of the sheath 56 shown in FIG. 6 on the sensor head 2 (see FIG. 3) side (hereinafter referred to as the sheath end), the order of the insulated wires 61a and 61b in the direction (first direction) is the direction. The order is the same as the order of the input terminals 41a and the output terminals 41b in the (first direction). Therefore, in the sensor head 2, the insulated wire 61a extending from the sheath end to the input terminal 41a and the insulated wire 61b extending from the sheath end to the output terminal 41b do not intersect each other.

Therefore, each of the insulated wires 61a and 61b extends substantially linearly from the sheath end toward each of the input terminal 41a and the output terminal 41b, is not twisted with each other, and is connected to the other insulated wires 62a and 62b. However, it is not twisted. In other words, between the sheath end and each of the input terminal 41a and the output terminal 41b, the insulated wire 61a is separated from the insulated wires 61b, 62a and 62b, and the insulated wire 61b is separated from the insulated wires 61a, 62a and 62b. It is separated. In other words, the insulated wire 61a exposed from the sheath 56 in the sensor head 2 is separated from the insulated wires 61b, 62a and 62b, and the insulated wire 61b is separated from the insulated wires 61a, 62a and 62b.

Further, among the insulated wires 61a, 61b, 62a and 62b arranged in a matrix in the cross section of the cable 3, the insulated wires 62a and 62b are arranged in the row direction (or column direction) (see FIG. 8). At the sheath end shown in FIG. 6, the order of the insulated wires 62a and 62b in the direction (first direction) is opposite to the order of the input terminals 42a and the output terminals 42b in the direction (first direction). Therefore, in the sensor head 2, the insulated wire 62a extending from the sheath end to the input terminal 42a and the insulated wire 62b extending from the sheath end to the output terminal 42b intersect each other.

<Effect of this embodiment>
Here, FIG. 10 shows a cross section of a mold used in a step of injection molding a sensor head 2 (see FIG. 2) which is a resin molded body. However, in FIG. 10, the insulated wires 61a, 61b, 62a and 62b are shown in a side view instead of a cross section.

As shown in FIG. 10, the mold 70 is provided with an injection port 71 for pouring the resin. The cable 3, the sensors IC 41, 42 and the holder 60, which are connected to each other in advance, are set in the mold 70, and the molten resin is injected into the mold 70 from the injection port 71, and the resin hardens to solidify the sensor head. 2 can be molded. The injection port 71 is provided at a position in contact with the lower end of the flange portion shown in FIG. 2, for example.

In this injection molding step, it is important not to provide a structure in the mold 70 that obstructs the flow of the resin. For example, when a large number of the plurality of insulated wires extending from the sheath end to the sensors ICs 41 and 42 are twisted to each other, it becomes difficult for the resin to flow between the twisted insulated wires.

FIG. 16 shows a connection state between the sensor IC constituting the wheel speed sensor, which is a comparative example, and the cable. The sensors IC 41 and 42 constituting the wheel speed sensor of the comparative example shown in FIG. 16 are the same as those used in the present embodiment. However, the order of the insulated wires 61a, 61b, 62a and 62b in the cable 3 is different from that of the present embodiment.

In the comparative example, among the insulated wires 61a, 61b, 62a and 62b arranged in a matrix in the cross section of the cable 3 (not shown), the insulated wires 61a and 61b connected to the upper sensor IC 41 are diagonally square. Each of the insulated wires 62a and 62b arranged at the position and connected to the lower sensor IC 42 is arranged at the other diagonal position of the quadrangle. That is, in the cross section of the cable 3, for example, the insulated wires 61a and 62a are lined up with each other in the first direction, and the insulated wires 62b and 61b are lined up with each other in the first direction. Further, in the cross section, the insulated wires 61a and 62b are aligned with each other in the second direction, and the insulated wires 62a and 61b are aligned with each other in the second direction.

In such a case, the four insulated wires 61a, 61b, 62a and 62b extending from the end of the sheath toward the sensor IC 41 and 42 in the sensor head intersect with each other and twist. When the cable 3 of the comparative example and the sensors ICs 41 and 42 are connected to each other and installed in a mold, and the sensor head is formed by injecting resin, the insulated wires 61a, 61b, 62a and 62b twisting each other It is difficult for resin to flow into. As a result, the sensor head is formed with a space remaining between the insulated wires 61a, 61b, 62a and 62b. If space remains in the sensor head, there arises a problem that the mechanical strength of the sensor head is lowered.

In particular, as shown in FIG. 10, when the four insulated wires are not exposed in the region directly below the injection port 71, a space is likely to be created between the twisted insulated wires. In such a case, the resin that has flowed into the mold 70 from the injection port 71 first hits the surface (side surface) of the sheath 56, and then is filled into the sensors IC 41 and 42 along the extending direction of the sheath 56. .. That is, instead of injecting the resin into the four insulated wires near the end of the sheath, the resin advances along the extending direction of the sheath 56 and each insulated wire, so that the resin tries to enter between the insulated wires. The pressure of the resin is smaller than the pressure of the resin that first hits the surface of the sheath 56 after the resin is injected. Therefore, a space is likely to be created between the twisted insulated wires.

Further, when a space remains in the sensor head, the moisture in the space or the moisture infiltrated into the space from the outside may cause corrosion of the core wire 50 or failure of the sensors IC 41 and 42. Therefore, from the viewpoint of improving the reliability of the rotational speed sensor, it is important to suppress the remaining space in the sensor head due to the twist of the insulated wire.

Further, when the insulated wires are twisted to each other, it is considered that the insulated wires are pressed against each other. If injection molding is performed in this case, the insulator of the insulated wire melts due to the temperature of the resin, which may cause a plurality of exposed core wires 50 to come into contact with each other to cause a short circuit. Such a problem becomes more remarkable as the number of insulated wires twisted from each other increases.

From the viewpoint of preventing the occurrence of the above space and the occurrence of a short circuit, it is conceivable to increase the length of the insulated wire from the terminals 57 and 58 of the sensors IC 41 and 42 to the sheath end. However, in this case, there arises a problem that the size of the sensor head becomes large. That is, it is desirable that the length of the insulated wire from the terminals 57 and 58 of the sensors IC 41 and 42 to the end of the sheath in the front-rear direction is short.

On the other hand, in the present embodiment, as shown in FIG. 8, among the insulated wires 61a, 61b, 62a and 62b arranged in a matrix in the cross section of the cable 3, the insulated wires 61a and 61b are in the row direction (or column direction). ) Side by side and adjacent to each other. Further, the insulated wires 62b and 62a are arranged side by side in the relevant direction and adjacent to each other. As a result, the insulated wires 61a and 61b can be connected to the upper sensor IC 41 without twisting each other. Therefore, the resin injected in the injection molding process described with reference to FIG. 10 flows around each of the linearly extending insulated wires 61a and 61b without being caught. Therefore, it is possible to prevent the space from remaining in the sensor head 2 shown in FIG. Therefore, it is possible to suppress a decrease in the strength of the sensor head 2 due to the existence of the space and a deterioration of the sensor head 2 due to the moisture in the space. That is, the quality of the resin mold of the sensor head 2 can be improved.

Further, since the insulated wires 61a and 61b are not twisted to each other, even if the insulators of the insulated wires 61a and 61b are melted in the injection molding process, it is possible to prevent the core wires 50 from being short-circuited with each other.

From the above, in the present embodiment, the reliability of the rotation speed sensor can be improved.

Further, in the present embodiment, the lengths of the insulated wires 61a, 61b, 62a and 62b from the terminals 57 and 58 of the sensors IC 41 and 42 to the sheath end are increased by preventing a large number of insulated wires from twisting each other. Can be shortened. Therefore, it is possible to prevent the sensor head 2 from becoming large. As a result, the manufacturing cost of the sensor head 2, that is, the manufacturing cost of the rotational speed sensor can be reduced. Further, for example, when the size of the sensor head 2 is the same as that of one rotation speed sensor in the conventional sensor IC, the design of the component that is an external device of the sensor head 2 and holds the sensor head 2 is changed. No need.

Further, since it is not necessary to twist the insulated wires 61a and 61b to each other, it becomes easy to arrange the sensors ICs 41 and 42 side by side and connect the core wires 50 and the terminals 57 and 58 as shown in FIG. Therefore, since the workability is improved, the manufacturing cost of the rotation speed sensor can be reduced. Further, even if the length of the insulated wire from the terminals 57 and 58 of the sensors IC 41 and 42 to the end of the sheath is short, such work can be easily performed, so that the sensor head 2 can be prevented from becoming large. Can be done.

As a method of forming a cable by combining four insulated wires into one, two anti-twisted insulated wires formed by bundling two insulated wires as stranded wires are prepared, and these two anti-twisted insulated wires are prepared. It is conceivable to form one cable by further bundling the stranded wires as stranded wires. However, this method makes the cable thicker and makes it harder to bend. On the other hand, in the present embodiment, the four insulated wires 61a, 61b, 62a and 62b are bundled as one stranded wire formed by crossing each other and twisting to form one cable 3. ing. Therefore, it is possible to realize a cable 3 that is thin and easy to bend.

In the present embodiment, the configuration in which the insulated wires 61a and 61b connected to the upper sensor IC 41 are not twisted and the insulated wires 62a and 62b connected to the lower sensor IC 42 are twisted has been described. Contrary to such a configuration, the insulated wires 61a and 61b connected to the upper sensor IC 41 are twisted, and the insulated wires 62a and 62b connected to the lower sensor IC 42 are not twisted. However, the same effect as that of the present embodiment can be obtained.

Here, the case where the sensors ICs 41 and 42 are separated from each other has been described, but the magnetoresistive elements 41c and 42c (see FIG. 4) are enclosed in the same resin to form one sensor IC. May be good. That is, the magnetoresistive elements 41c and 42c and the resin may form one sensor IC provided with the four terminals 57 and 58, and the sensor IC may be enclosed in the sensor head 2.

(Embodiment 2)
Below, by devising the arrangement of the insulated wires in the cable that bundles the four insulated wires, it is possible to prevent the insulated wires exposed from the sheath from twisting in the sensor head, thereby improving the reliability of the rotational speed sensor. Explain what to improve.

<Structure of rotational speed sensor of this embodiment>
As shown in FIGS. 11 to 15, the configuration of the sensor head 2 and the cable 3 constituting the rotational speed sensor of the present embodiment is in the respective cables 3 of the insulated wires 62a and 62b connected to the lower sensor IC 42. It is the same as the first embodiment except that the arrangement in is reversed.

That is, as shown in FIG. 11, in the sensor head 2, the sensors IC 41 and 42 are vertically stacked with both detection surfaces facing upward. Further, a plurality of core wires 50 passing through the cable 3 connected to the rear of the sensor head 2 are connected to the terminals 57 and 58 of the sensors IC 41 and 42, respectively.

FIG. 13 is a bottom view of the lower sensor IC 42 as viewed from below, and the structures of the insulated wires 61a and 61b connected to the upper sensor IC 41 and the upper sensor IC are the same as those shown in FIG. As shown in FIGS. 12 and 13, unlike the first embodiment, the insulated wires 62a and 62b do not intersect with each other and are not twisted with each other. This is because, as shown in FIG. 14, the positions of the insulated wires 62a and 62b are opposite to the positions of the insulated wires 62a and 62b shown in FIG.

Specifically, in the cross section along the radial direction of the cable 3 as shown in FIG. 14, the four insulated wires 61a, 61b, 62a and 62b are located at positions corresponding to, for example, the four corners of a regular quadrangle, respectively. That is, in the cross section, the insulated wires 61a, 61b, 62a and 62b are arranged in a matrix. Here, in the cross section, the insulated wires 61a and 61b are lined up with each other in the first direction, and the insulated wires 62a and 62b are lined up with each other in the first direction. Further, in the cross section, the insulated wires 61a and 62a are lined up with each other in the second direction, and the insulated wires 61b and 62b are lined up with each other in the second direction.

As a result, the positions of the input terminal 41a, the output terminal 41b, the input terminal 42a, and the output terminal 42b and the positions of the insulated wires 61a, 61b, 62a, and 62b at the sheath end correspond to each other. Therefore, when the input terminal 41a, the output terminal 41b, the input terminal 42a and the output terminal 42b and the insulated wires 61a, 61b, 62a and 62b are connected to each other, two or more of the insulated wires 61a, 61b, 62a and 62b, respectively. It is possible to prevent the insulated wires of the above from crossing between the terminals 57 and 58 and the sheath end.

That is, the insulated wires 61a, 61b, 62a and 62b are not in contact with each other and are separated from each other between the sheath end and each of the input terminal 41a, the output terminal 41b, the input terminal 42a, and the output terminal 42b. There is. In other words, the insulated wires 61a, 61b, 62a and 62b exposed from the sheath 56 in the sensor head 2 are separated from each other.

When connecting the core wire 50 to each of the sensors IC 41 and 42, for example, as shown in FIG. 15, the upper sensor IC 41 with the detection surface facing up and the lower sensor IC 42 with the back surface facing up are sideways. Perform resistance welding side by side. After that, by changing the directions of the sensors ICs 41 and 42 by 90 degrees in opposite directions, the sensors ICs 41 and 42 can be overlapped with the detection surfaces facing the same direction.

<Effect of this embodiment>
In the present embodiment, as shown in FIG. 14, among the insulated wires 61a, 61b, 62a and 62b arranged in a matrix in the cross section of the cable 3, the insulated wires 61a and 61b are arranged in the row direction (or column direction). They are adjacent to each other, and the insulated wires 62a and 62b are also adjacent to each other side by side in the relevant direction. As a result, the insulated wires 61a, 61b, 62a and 62b can all be connected to the sensors IC 41 and 42 without twisting each other. Therefore, in the injection molding process described with reference to FIG. 10, since the resin easily flows around each of the linearly extending insulated wires 61a, 61b, 62a and 62b, a space remains in the sensor head 2 shown in FIG. It can be suppressed. Therefore, it is possible to suppress a decrease in the strength of the sensor head 2 due to the existence of the space and a deterioration of the sensor head 2 due to the moisture in the space.

In the present embodiment, unlike the first embodiment, not only the insulated wires 61a and 61b but also the insulated wires 62a and 62b are not twisted to each other in the sensor head 2. This is because, in the cross section of the cable 3 shown in FIG. 14, the order of the insulated wires 61a connected to the input terminal 41a and the insulated wires 61b connected to the output terminal 41b in the first direction is connected to the input terminal 42a. This is because the order of the insulated wires 62a and the insulated wires 62b connected to the output terminals 42b in the first direction is the same. As a result, when the sensors ICs 41 and 42 having the same structure and function are overlapped with their respective detection surfaces facing in the same direction, the terminals 57 without crossing the insulated wires 61a, 61b, 62a and 62b with each other. , 58 can be connected. Therefore, since it is possible to eliminate the portion where the resin is difficult to flow due to the twist of the insulated wire, in the present embodiment, the quality of the resin mold can be further improved as compared with the first embodiment.

Further, since the insulated wires 61a, 61b, 62a and 62b are not twisted with each other, even if the insulators of the insulated wires 61a, 61b, 62a and 62b are melted in the injection molding process, the core wires 50 are short-circuited with each other. It can be suppressed.

From the above, in the present embodiment, the reliability of the rotation speed sensor can be improved.

Further, in the present embodiment, the lengths of the insulated wires 61a, 61b, 62a and 62b from the terminals 57 and 58 of the sensors IC 41 and 42 to the sheath end are increased by preventing a large number of insulated wires from twisting each other. Can be shortened. Therefore, it is possible to prevent the sensor head 2 from becoming large.

Further, since it is not necessary to twist the insulated wires 61a, 61b, 62a and 62b to each other, the work of arranging the sensors ICs 41 and 42 side by side and connecting the core wires 50 and the terminals 57 and 58 becomes easy as shown in FIG. Therefore, the manufacturing cost of the rotation speed sensor can be reduced. Further, even if the length of the insulated wire from the terminals 57 and 58 of the sensors IC 41 and 42 to the end of the sheath is short, such work can be easily performed, so that the sensor head 2 can be prevented from becoming large. Can be done.

Here, the case where the sensors ICs 41 and 42 are separated from each other has been described, but the magnetoresistive elements 41c and 42c (see FIG. 4) are enclosed in the same resin to form one sensor IC. May be good. That is, the magnetoresistive elements 41c and 42c and the resin may form one sensor IC provided with the four terminals 57 and 58, and the sensor IC may be enclosed in the sensor head 2.

Although the invention made by the present inventors has been specifically described above based on the embodiment thereof, the present invention is not limited to the embodiment and can be variously modified without departing from the gist thereof. be.

For example, the detection element included in the sensor IC built in the sensor head is an anisotropic magnetoresistance effect element (AMR (Anisotropic magnetoresistance effect) element) or a tunnel magnetoresistance effect element (TMR (Tunnel magnetoresistance effect) element). It may be a Hall element.

The method of connecting the core wire and the output terminal of the sensor IC is not limited to welding, and may be, for example, soldering. Further, the core wire and the output terminal of the sensor IC may be connected via the connection terminal. In this case, for example, one end of the connection terminal and the core wire are caulked and connected, and the other end of the connection terminal and the output terminal are caulked and connected.

The present invention can be applied to a rotation speed sensor other than the wheel speed sensor, and when applied, the same effect as described above is obtained.

2 Sensor head 3 Cable 40 Sensor IC
41 Sensor IC (upper sensor IC)
41a, 42a Input terminal 41b, 42b Output terminal 42 Sensor IC (lower sensor IC)
41c, 42c Magnetoresistive sensor 50, 51a, 51b, 52a, 52b Core wire 61a, 61b, 62a, 62b Insulated wire

Claims (7)

A sensor head that includes a sensor holder and a cable holder,
A cable extending from the cable holding portion and
It has a first sensor IC and a second sensor IC, which are embedded in the sensor holding portion and output an electric signal according to a magnetic field fluctuation.
The first sensor IC has a first detection surface, a first back surface opposite to the first detection surface, and a first terminal and a second terminal.
The second sensor IC has a second detection surface, a second back surface opposite to the second detection surface, and a third terminal and a fourth terminal.
The cable has a first insulated wire electrically connected to the first terminal, a second insulated wire electrically connected to the second terminal, and a second electrically connected to the third terminal. An outer skin that collectively covers the three insulated wires, the fourth insulated wire electrically connected to the fourth terminal, the first insulated wire, the second insulated wire, the third insulated wire, and the fourth insulated wire. Including and
The first insulated wire, the second insulated wire, the third insulated wire, and the fourth insulated wire constitute a stranded wire twisted to each other.
In the cross section along the radial direction of the cable, the first insulated wire and the second insulated wire are arranged in the first direction, and the third insulated wire and the fourth insulated wire are arranged in the first direction. A rotational speed sensor in which the first insulated wire or the second insulated wire and the third insulated wire are arranged in a second direction intersecting with the first direction. In the rotation speed sensor according to claim 1,
The first back surface and the second detection surface face each other.
A part of the first terminal and the third terminal overlap each other in a plan view.
The second terminal and the fourth terminal are rotational speed sensors in which parts of the second terminal and the fourth terminal overlap each other in a plan view. In the rotation speed sensor according to claim 1 or 2.
In the cross section along the radial direction of the cable, the first insulated wire and the third insulated wire are arranged in the second direction, and the second insulated wire and the fourth insulated wire are arranged in the second direction. The rotation speed sensor. The rotational speed sensor according to any one of claims 1 to 3.
The first terminal is an input terminal of the first sensor IC.
The second terminal is an output terminal of the first sensor IC.
The third terminal is an input terminal of the second sensor IC.
The fourth terminal is a rotation speed sensor which is an output terminal of the second sensor IC. In the rotation speed sensor according to any one of claims 1 to 4.
The sensor head is a rotational speed sensor made of resin. The rotational speed sensor according to any one of claims 3 to 5.
A rotational speed sensor in which the first insulated wire, the second insulated wire, the third insulated wire, and the fourth insulated wire exposed from the outer skin in the sensor head are separated from each other. The rotational speed sensor according to any one of claims 1 to 6.
Each of the first sensor IC and the second sensor IC is a rotational speed sensor provided with a magnetoresistive effect element as a detection element.

Images