CN211785600U - Rotating speed sensor - Google Patents

Abstract

The utility model provides a revolution speed transducer. A rotation speed sensor having a sensor head in which a plurality of sensor ICs are embedded, wherein the reliability of the rotation speed sensor is improved. The rotation speed sensor has a sensor head made of resin, sensor ICs (41, 42) embedded in the sensor head, and a cable (3) having an end portion in the sensor head. In the cable (3), insulated wires (61a, 61b) connected to the sensor IC (41) and insulated wires (62a, 62b) connected to the sensor IC (42) pass through. Among insulated wires (61a, 61b, 62a, 62b) arranged in a matrix shape on a cross section of a cable (3), the insulated wires (61a, 61b) are arranged in a first direction, and the insulated wires (62a, 62b) are arranged in the first direction.

Description

Rotating speed sensor

Technical Field

The utility model relates to a sensor for detecting the rotational speed of object especially relates to a sensor that is fit for detecting the rotational speed of wheel.

Background

Today, various sensors are mounted on vehicles such as automobiles and motorcycles, and one of the sensors for vehicles is a rotational speed sensor. The rotation speed sensor is mounted on a vehicle, for example, to detect the rotation speed of a wheel. The rotation degree sensor mounted on the vehicle for the above purpose is generally called a wheel speed sensor. A rotation speed sensor as a wheel speed sensor is mounted on a vehicle as one of components of a brake anti-lock brake system (ABS system) for preventing wheel lock, a traction control system for preventing wheel slip, and the like.

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 incorporates a magnetic sensor IC (hereinafter referred to as a sensor IC) including a detection element such as a hall element or a magnetoresistive effect element. The sensor head is disposed in the vicinity of a magnetic encoder or a rotor or the like that rotates together with the wheel. A sensor IC (detection element) built in the sensor head detects a change in magnetic field around the sensor head generated with rotation of a magnetic encoder, a rotor, or the like, and outputs an electric signal corresponding to the change in magnetic field (wheel rotation speed). The electric signal output from the sensor IC is transmitted by a cable and is input to a control unit, a control device, or the like via a connector.

Conventionally, there are only 1 sensor IC built in a sensor head. On the other hand, with the development of an automatic driving system, a driving support system, and the like, there is an increasing demand for reliability and stability of a rotation speed sensor including a wheel speed sensor. Therefore, a solution for improving the reliability and stability of the rotation speed sensor by increasing the number of sensor ICs built in the sensor head is being studied. That is, the redundancy of the revolution speed sensor is being studied.

Patent document 1 (japanese patent application laid-open No. 2017-96828) discloses a wheel speed sensor having two detection element units mounted thereon. Here, two electric wires connected to the detection element portion are collected into one sheathed electric wire, and the respective sheathed electric wires connected to the two detection element portion sensors are collected into one rubber tube, whereby four electric wires in total are collected into one.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2017-96828

SUMMERY OF THE UTILITY MODEL

Problem to be solved by utility model

In order to make the rotational speed sensor redundant, when two sensor ICs are incorporated in the sensor head, it is conceivable to concentrate two wirings (Vcc wiring and GND wiring for sensor power supply) connected to the respective sensor ICs, that is, four wirings in total into one. When the four wires are collected into one in the sensor head as a resin molded body, if the wires are twisted with each other, the resin constituting the sensor head cannot be filled between the wires, which causes a problem that the reliability of the rotation speed sensor is lowered.

Other problems and novel features will be apparent from the description and drawings of this specification.

Means for solving the problems

The embodiments disclosed in the present application are briefly described below as representative embodiments.

The rotation speed sensor according to one embodiment includes a sensor head, a first sensor IC and a second sensor IC provided in the sensor head so as to overlap each other, and a cable having an end portion in the sensor head. 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 constitute one twisted wire. In a cross section of the cable, the first insulated wire and the second insulated wire are arranged in a 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 in a second direction crossing the first direction.

A rotation speed sensor according to claim 1 is characterized by comprising: a sensor head including a sensor holding portion and a cable holding portion; a cable extending from the cable holding portion; and a first sensor IC and a second sensor IC embedded in the sensor holding portion and outputting an electric signal according to a change in a magnetic field, the first sensor IC having a first detection surface, a first back surface opposite to the first detection surface, a first terminal, and a second terminal, the second sensor IC having a second detection surface, a second back surface opposite to the second detection surface, a third terminal, and a fourth terminal, the cable including: a first insulating wire electrically connected to the first terminal; a second insulated wire electrically connected to the second terminal; a third insulated wire electrically connected to the third terminal; a fourth insulated wire electrically connected to the fourth terminal; and a sheath that collectively covers the first insulated wire, the second insulated wire, the third insulated wire, and the fourth insulated wire, wherein the first insulated wire, the second insulated wire, the third insulated wire, and the fourth insulated wire form twisted strands, the first insulated wire and the second insulated wire are arranged in a 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 in a second direction that intersects the first direction, in a cross section along a radial direction of the cable.

A rotation speed sensor according to claim 2 is characterized in that the first rear surface and the second detection surface face each other, the first terminal and the third terminal partially overlap each other in a plan view, and the second terminal and the fourth terminal partially overlap each other in a plan view.

The rotation speed sensor as set forth in claim 3 is characterized in that, in the cross section in 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 according to claim 4 is characterized in that 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, and the fourth terminal is an output terminal of the second sensor IC.

The rotation speed sensor according to claim 5 is characterized in that the sensor head is made of resin.

The rotation speed sensor according to claim 6 is characterized in that the first insulated wire, the second insulated wire, the third insulated wire and the fourth insulated wire exposed from the outer cover in the sensor head are separated from each other.

The rotation speed sensor according to claim 7 is characterized in that each of the first sensor IC and the second sensor IC has a magnetoresistance effect element as a detection element.

A rotation speed sensor according to claim 8 is characterized in that a separator is provided between the first insulated wire and the second insulated wire and between the third insulated wire and the fourth insulated wire.

The rotation speed sensor according to claim 9 is characterized in that the first sensor IC and the second sensor IC operate simultaneously.

Effect of the utility model

According to the utility model discloses, can improve speed sensor's reliability.

Drawings

Fig. 1 is a schematic diagram showing a configuration of a rotation speed sensor according to embodiment 1;

fig. 2 is a perspective view of the sensor head shown in fig. 1.

Fig. 3 is a perspective view of the sensor head shown in fig. 1.

FIG. 4 is a cross-sectional view of the sensor head shown in FIG. 2 taken along line A-A;

fig. 5 is a perspective view showing a connection state between the sensor IC and the cable in the sensor head shown in fig. 2.

Fig. 6 is a plan view showing a connection state between the sensor IC and the cable in the sensor head shown in fig. 2.

Fig. 7 is a bottom view showing a connection state of the sensor IC and the cable in the sensor head shown in fig. 2.

FIG. 8 is a cross-sectional view taken along line B-B of the cable shown in FIG. 6;

fig. 9 is a schematic diagram showing a connection state between the sensor IC and the cable in the sensor head shown in fig. 2.

Fig. 10 is a sectional view of a mold used in a manufacturing process of a rotation speed sensor according to embodiment 1;

fig. 11 is a perspective view showing a sensor head constituting a revolution speed sensor according to embodiment 1.

Fig. 12 is a perspective view showing a connection state between the sensor IC and the cable in the sensor head shown in fig. 11.

Fig. 13 is a bottom view showing a connection state of the sensor IC and the cable in the sensor head shown in fig. 11.

Fig. 14 is a cross-sectional view taken along line C-C of the cable shown in fig. 13.

Fig. 15 is a schematic view showing a connection state between the sensor IC and the cable in the sensor head shown in fig. 11.

Fig. 16 is a schematic diagram showing a connection state between a sensor IC and a cable that constitute a rotation speed sensor of a comparative example.

In the figure:

2-sensor head, 3-cable, 40-sensor IC, 41-sensor IC (upper sensor IC), 41a, 42 a-input terminal, 41b, 42 b-output terminal, 42-sensor IC (lower sensor IC), 41c, 42 c-magnetoresistance effect element, 50, 51a, 51b, 52a, 52 b-core wire, 61a, 61b, 62a, 62 b-insulated wire.

Detailed Description

(embodiment mode 1)

Hereinafter, an example of an embodiment of the rotation speed sensor according to 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 component of an ABS system.

< construction of rotation speed sensor in the present embodiment >

Fig. 2 and 3 used in the following description are perspective views showing the sensor head 2 from directions different from each other. In fig. 3, the cable 3, the sensor ICs 41, 42, and terminals and insulated wires therebetween are illustrated in perspective.

As shown in fig. 1, a wheel speed sensor 1A of a 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 disposed in the vicinity of a magnetic encoder 5 that rotates together with a wheel not shown. Specifically, the sensor head 2 is fixed to a vehicle body (hub, yoke, suspension, etc.) so that its positional relationship with the magnetic encoder 5 is in a predetermined positional relationship. On the periphery of the magnetic encoder 5, N-pole portions and S-pole portions are alternately provided along the rotation direction of the magnetic encoder 5. Therefore, if the magneto encoder 5 rotates with the rotation of the wheel, a magnetic field variation is generated around the sensor head 2. The sensor head 2 incorporates a magnetic sensor IC (sensor IC) for detecting a change in magnetic field and outputting an electric signal corresponding to the change in magnetic field. The sensor head 2 and the connector 4 are connected via one cable 3. An electric signal output from a sensor IC built in the sensor head 2 is transmitted to the connector through the cable 3 and input to a connection terminal of the connector 4. The connector 4 is connected to, for example, a control section or a control device of the ABS system, or a control section or a control device that comprehensively controls various systems including the ABS system, or the like.

As shown in fig. 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 holding portion 30 provided on the other side of the flange portion 10. These flange portion 10, sensor holding portion 20, and cable holding portion 30 are integrally molded from resin. In other words, the flange portion 10, the sensor holding portion 20, and the cable holding portion 30 are each a part of a resin molded body formed by injection molding.

As shown in fig. 1, the flange portion 10 has a front face 11a and a rear face 11b parallel to each other, and exhibits a substantially plate-like appearance as a whole. As shown in fig. 1, 2, and 3, the flange portion 10 has a through hole 12 for inserting a fixing member (e.g., a bolt) for fixing the sensor head 2 at a predetermined position. 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 opens at the rear surface 11b of the flange portion 10. As shown in fig. 2, an annular reinforcing member 13 is provided inside the through hole 12. The reinforcing member 13 of the present embodiment is made of metal, but the reinforcing member 13 is not limited to being made of metal and may be made of resin, for example.

As shown in fig. 1, 2, and 3, the sensor holding portion 20 and the cable holding portion 30 have a substantially cylindrical 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 presents a substantially cylindrical appearance and the tip side presents a substantially square-cylindrical appearance. On the other hand, the cable holding portion 30 protrudes rearward from the rear surface 11b of the flange portion 10 opposite to the front side, and has a substantially cylindrical outer appearance over the entire length.

Here, the thickness direction of the flange portion 10 is referred to as the "front-rear direction", and the height direction (longitudinal direction) of the flange portion 10 is referred to as the "up-down direction". In addition, a direction orthogonal to both the front-rear direction and the up-down direction is referred to as a "left-right direction". In the front-rear direction, the protruding direction (first direction) of the sensor holding portion 20 with respect to the flange portion 10 is set to "front", and the protruding direction (second direction) of the cable holding portion 30 with respect to the flange portion 10 is set to "rear". In the vertical direction, the side where the through-hole 12 is provided is referred to as "lower", and the side opposite to the side where the through-hole 12 is provided is referred to as "upper". The base end side of the sensor holding portion 20 having a substantially cylindrical appearance may be referred to as a "base end portion 20 a", and the distal end side of the sensor holding portion 20 having a substantially square cylindrical appearance may be referred to as a "distal end portion 20 b". In other words, the portion exhibiting a substantially cylindrical appearance is the base end portion 20a, and the portion exhibiting a substantially square cylindrical appearance is the tip end portion 20 b.

As shown in fig. 3 and 4, the sensor head 2 incorporates a plurality of sensor ICs 40, and the sensor IC40 includes a detection element for detecting a change in magnetic field. In other words, the sensor head 2 incorporates a plurality of sensor ICs 40 that output electric signals in accordance with changes in magnetic field. In the present embodiment, a total of two sensor ICs (first sensor ICs) 41 and 42 are embedded at the tip of the sensor holding portion 20. More specifically, the two sensor ICs 41 and 42 are embedded in the vicinity of the end face of the distal end portion 20b of the sensor holder 20.

The sensor IC41 and the sensor IC42 have magnetoresistive effect elements 41c and 42c as detection elements, respectively. The magnetoresistance effect elements 41c and 42c in this embodiment are giant magnetoresistance effect elements (gmr (giant magnetoresistive) elements). The sensor IC41 and the sensor IC42 are overlapped up and down in a state where both detection surfaces are directed upward. In the following description, the sensor IC41 may be referred to as an "upper sensor IC 41", and the sensor IC42 may be referred to as a "lower sensor IC 42". However, this difference is merely a difference for convenience of explanation. On the other hand, the sensor IC41 and the sensor IC42 are sometimes collectively referred to as "sensor IC 40".

As shown in fig. 4, the front end 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 of the cable 3 is molded on the cable holding part 30. As a result, the cable 3 extends rearward from the end face 30a of the cable holding portion 30. Fig. 4 is a cross-sectional view a-a of the sensor head shown in fig. 2, showing not the cross-section but the side view from the left side for 4 insulated wires in the through-cable 3.

As shown in fig. 4 to 7, the cable 3 is a multicore cable including 4 core wires 50. More specifically, the cable 3 is a multicore cable including one pair of core wires 50 connected to the upper side sensor IC41 and another pair of core wires 50 connected to the lower side 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 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 of the core wires 50 covered with the insulator 55 is entirely covered with a sheath (sheath, insulator) 56 in a state twisted with each other (see fig. 4). Specifically, the core wire 51a and the insulator 55 covering the core wire 51a constitute an insulated wire (first insulated wire) 61a, and the core wire 51b and the insulator 55 covering the core wire 51b constitute an insulated wire (second insulated wire) 61b (refer to fig. 5 and 6). Also, the core wire 52a and the insulator 55 covering the core wire 52a constitute an insulated wire (third insulated wire) 62a, and the core wire 52b and the insulator 55 covering the core wire 52b constitute an insulated wire (fourth insulated wire) 62b (see fig. 5 and 7).

That is, the cable 3 is a four-core cable having four twisted insulated wires 61a, 61b, 62a, 62b and a sheath 56 which integrally covers the four insulated wires 61a, 61b, 62a, 62b and is assembled into one. The core wire 50 in the present embodiment is a stranded cord composed of a plurality of copper alloy wires containing tin. The insulator 55 is made of flame-retardant crosslinked polyethylene, and the sheath 56 is made of thermoplastic polyurethane. 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 fig. 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, two core wires 51a, 51b are connected to the upper side sensor IC41, and as shown in fig. 7, the other two core wires 52a, 52b are connected to the lower side sensor IC 42. More specifically, the core wire 51a is connected to the input terminal (first terminal) 41a of the upper side sensor IC41, and the core wire 51b is connected to the output terminal (second terminal) 41b of the upper side sensor IC 41. Likewise, the core wire 52a is connected to the input terminal (third terminal) 42a of the lower sensor IC42, and the core wire 52b is connected to the output terminal (fourth terminal) 42b of the lower sensor IC 42.

The input terminals 41a, 42a and the output terminals 41b and 42b have a bar shape, respectively. The core wire 51a is resistance-welded to the input terminal 41a, and the core wire 51b is resistance-welded to the output terminal 41 b. The core wire 52a is resistance-welded to the input terminal 42a, and the core wire 52b is resistance-welded to the output terminal 42 b. In the following description, the input terminal 41a and the output terminal 41b are collectively referred to as "terminal 57", and the input terminal 42a and the output terminal 42b are 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 IC40 shown in fig. 4, 6, and 7 are held by the bracket 60. In other words, the end portion of the sheath 56, the core wire 50, the sensor IC40 including the terminal 57 and the terminal 58 are built in the sensor head 2 shown in fig. 2 in a state of being held by the bracket 60. In fig. 6 and 7, the plate-shaped separators 66, 67 and the side walls 64, 65 constituting the bracket 60 are not shown in detail and are indicated by dashed-dotted lines.

The bracket 60 has a pair of opposed side wall portions 64, 65 and a support plate 63 spanning these side wall portions 64, 65. The core wires 51a, 51b and the upper side sensor IC41 (see fig. 5 and 6) including the terminal 57 are disposed on the upper surface side of the support plate 63. On the other hand, the core wires 52a, 52b and the lower side sensor IC42 (see fig. 5 and 7) including the terminals 58 are disposed on the lower surface side of the support plate 63.

A plate-like partition plate 66 inserted between the core wires 51a, 51b is provided so as to protrude. In other words, the partition 66 is a partition wall interposed between the pair of core wires 51a, 51b connected to the same sensor IC (upper side sensor IC 41). A partition plate 67, which is the same as the partition plate 66, is also protrudingly provided on the lower surface of the support plate 63. The partition 67 is also a partition wall interposed between the pair of core wires 52a, 52b connected to the same sensor IC (lower sensor IC 42).

As shown in fig. 6, the partition plate 66 extends forward beyond the ends of the core wires 51a, 51b and is interposed between the input terminal 41a and the output terminal 41 b. As shown in fig. 7, the partition 67 extends forward across the end portions of the core wires 52a, 52b, and is interposed between the input terminal 42a and the output terminal 42 b. As a result, the core wire 51a and the input terminal 41a are disposed at the upper portion between the partition plate 66 and the side wall portion 64, and the core wire 51b and the output terminal 41b are disposed at the upper portion between the partition plate 66 and the side wall portion 65 (see fig. 6). The core wire 52a and the input terminal 42a are disposed at a lower portion between the partition 67 and the side wall portion 64, and the core wire 52b and the output terminal 42b are disposed at a lower portion between the partition 67 and the side wall portion 65 (see fig. 7).

The partition plates 66 shown in fig. 6 function to position the core wires 51a, 51b, the input terminal 41a, and the output terminal 41b at predetermined positions on the bracket 60, and function to prevent the core wires 51a and 51b from being short-circuited, and the input terminal 41a and the output terminal 41b from being short-circuited. The partition plates 67 shown in fig. 7 function to position the core wires 52a, 52b, the input terminal 42a, and the output terminal 42b at predetermined positions on the bracket 60, and function to prevent short-circuiting of the core wires 52a and 52b, and short-circuiting of the input terminal 42a and the output terminal 42 b.

As shown in fig. 8, inside the sheath 56 constituting the cable 3, 4 insulated wires 61a, 61b, 62a and 62b pass through. That is, the cable 3 binds the four insulated wires 61a, 61b, 62a, and 62b together.

The cross section of the cable 3 shown in fig. 8 is a cross section along the width direction (radial direction) of the cable 3, and is a cross section orthogonal to the extending direction of the cable 3. In this cross section, four insulated electric wires 61a, 61b, 62a, and 62b are located at, for example, four corners of a square, respectively. That is, the insulated wires 61a, 61b, 62a, and 62b are arranged in a matrix. Here, in the cross section, the insulated wires 61a, 61b are lined up in the first direction, and the insulated wires 62b, 62a are lined up in the first direction. Also, in the cross section, the insulated wires 61a, 62b are lined up in the second direction, and the insulated wires 61b, 62a are lined up in the second direction. The first direction and the second direction are directions along the cross section and cross each other. The first direction and the second direction are, for example, orthogonal to each other. In fig. 8, four insulated wires 61a, 61b, 62a, and 62b are separated from each other in the sheath 56, but adjacent insulated wires may contact each other. That is, the insulated wire 61a may be in contact with the insulated wires 61b and 62b, the insulated wire 61b may be in contact with the insulated wires 61a and 62a, the insulated wire 62a may be in contact with the insulated wires 61b and 62b, and the insulated wire 62b may be in contact with the insulated wires 61a and 62 a. In addition, each of the four insulated electric wires 61a, 61b, 62a, and 62b may be located at four corners of a parallelogram (e.g., a diamond shape) instead of a square.

Fig. 9 shows a schematic view of a state in which the sensor ICs 41, 42 are arranged in the lateral direction (expanded state) without overlapping in the vertical direction in the sensor head 2 (see fig. 2). The upper sensor IC41 has a nearly rectangular layout in plan view, for example. The planar view referred to herein is a state in which the upper sensor IC41 is viewed from a direction (upward) 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 substantially rectangular upper sensor IC41 in plan view, and are arranged along the one side. The lower sensor IC42 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 IC42 in plan view, and are arranged along the one side.

In fig. 9, the detection surface of the upper sensor IC41 is directed upward, and the detection surface of the lower sensor IC42 is directed 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 IC41 is directed downward, and the back surface (second back surface) on the opposite side of the detection surface (main surface, second detection surface) of the lower sensor IC42 is directed upward. In the process of connecting the core wires 50 to the sensor ICs 41 and 42, respectively, it is possible to arrange the two sensor ICs 41 and 42 so that the main surface (upper surface) of the upper sensor IC41 and the back surface (lower surface) of the lower sensor IC42 face upward, and solder the core wires 50 to the terminals 57, 58 in this state. Thereafter, the directions of the sensor ICs 41 and 42 are changed by 90 degrees in opposite directions, so that the sensor ICs 41 and 42 can be overlapped with each other with their detection surfaces facing the same direction. However, in this connection process, the detection surfaces of the sensor ICs 41 and 42 may face upward or downward.

In the drawings of the present application, for the sake of convenience of understanding the directions of the detection surface and the back surface of each of the sensor ICs 41 and 42, a portion inclined at one corner of each of the sensor ICs 41 and 42 having a substantially rectangular planar shape is shown. In contrast, the planar shape of the sensor IC41 may be left-right symmetric in the direction in which the input terminal 41a and the output terminal 41b are side by side. As does sensor IC 42.

In addition, the detection surfaces of the sensor ICs 41, 42 do not necessarily face in exactly the same direction. In other words, each detection face of the sensor ICs 41, 42 need not be perfectly parallel.

The input terminal 41a is a power supply voltage terminal for supplying a power supply voltage (Vcc) to the upper sensor IC41, and the insulated wire 61a including the core wire 51a connected to the input terminal 41a is a power supply wiring (positive electrode wiring). Further, the output terminal 41b is a ground terminal for connecting the upper side sensor IC41 to the ground potential (GND), and the insulated wire 61b including the core wire 51b connected to the output terminal 41b is a ground wiring (negative wiring).

Also, the input terminal 42a is a power supply voltage terminal for supplying a power supply voltage (Vcc) to the lower sensor IC42, and the insulated wire 62a including the core wire 52a connected to the input terminal 42a is a power supply wiring (positive electrode wiring). Further, the output terminal 42b is a ground terminal for connecting the lower sensor IC42 to the ground potential (GND), and the insulated wire 62b including the core wire 52b connected to the output terminal 42b is a ground wiring (negative wiring).

The sensor IC41, the IC42, and the cable connected to each other in this manner are stacked one on top of the other with their detection surfaces facing upward, as shown in fig. 5. This is because the sensor ICs 41 and 42 have the same function. One of the sensor ICs 41, 42 is a backup element, for example, to avoid the tachometer sensor from losing its function and failing to function properly when the other is inoperable due to a malfunction or the like. Therefore, each detection surface of the sensor IC41, IC42 must face in the same direction. In other words, the rear surface of the upper side sensor IC41 is disposed facing the detection surface of the lower side sensor IC 42.

Assuming that the respective detection surfaces of the sensor ICs 41, IC42 face in different directions from each other, one sensor IC cannot be used as a backup because the rotational direction of the wheel detected by the sensor IC41 and the rotational direction of the wheel detected by the sensor IC42 are different from each other. Here, the sensor ICs 41, IC42 normally operate simultaneously. That is, although the detection surface and the back surface of the sensor IC are shown separately, the back surface may be a detection surface capable of detecting the wheel rotation speed. However, when the back surface faces the wheel side, the reverse rotation is detected, unlike when the detection surface faces the wheel side.

As described above, the same elements are used for sensor IC41 and IC42, respectively. That is, the positional relationships of the input terminals and the output terminals of the sensor IC41 and the sensor IC42 with respect to the detection surface (main surface) are the same. Specifically, the output terminal 41b is arranged on the left side of the input terminal 41a, and in the direction in which the input terminal 41a and the output terminal 41b are arranged and the direction (vertical direction) perpendicular to the plane along the direction in which the input terminal 41a and the output terminal 41b extend, the main surface (detection surface) is located on the upper side of the upper sensor IC41, and the back surface is located on the lower side. In this case, the configuration of the lower sensor IC42 is also the same, that is, the output terminal 42b is arranged on the left side of the input terminal 42a, and the main surface (detection surface) is located on the upper side of the lower sensor IC42 and the back surface is located on the lower side in the direction in which the input terminal 42a and the output terminal 42b are arranged and the direction (up-down direction) perpendicular to the plane along the direction in which the input terminal 42a and the output terminal 42b extend, respectively.

The positional relationship described above may be changed as appropriate. For example, the positional relationship of the input terminal 41a and the output terminal 41b may be reversed. However, even in this case, the positional relationship of the input terminal and the output terminal with respect to each detection face (main face) of the sensor ICs 41, IC42 is the same. That is, the upper main surface (detection surface) of the upper sensor IC41 and the main surface (detection surface) of the lower sensor IC42 face the same direction, the input terminals 41a and 42a overlap each other in a plan view, and the 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 shape on 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). In the end portion (hereinafter referred to as a jacket end portion) on the sensor head 2 (see fig. 3) side of the jacket 56 shown in fig. 6, the arrangement order of the insulated wires 61a, 61b in this direction (first direction) is the same as the arrangement order of the input terminals 41a and the output terminals 41b in this direction (first direction). Therefore, in the sensor head 2, the insulated wires 61a extending from the jacket end to the input terminals 41a and the insulated wires 61b extending from the jacket end to the output terminals 41b do not cross each other.

Therefore, each of the insulated electric wires 61a, 61b extends from the sheath end toward the respective input terminal 41a and output terminal 41b in a substantially linear shape, and is not twisted with each other, and is not twisted with the other insulated electric wire 62a, 62 b. 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, 62b, and the insulated wire 61b is separated from the insulated wires 61a, 62 b. In other words, the insulated wires 61a exposed from the sheaths 56 in the sensor head 2 are separated from the insulated wires 61b, 62a, 62b, and the insulated wires 61b are separated from the insulated wires 61a, 62 b.

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). In the sheath end portion shown in fig. 6, the arrangement order of the insulated wires 62a, 62b in the direction (first direction) is opposite to the arrangement order of the input terminals 42a and the output terminals 42b in the direction (first direction). Therefore, in the sensor head 2, the insulated electric wires 62a extending from the jacket end to the input terminals 42a and the insulated electric wires 62b extending from the jacket end to the output terminals 42b cross each other.

< effects of the present embodiment >

Here, fig. 10 shows a cross section of a mold used in a step of injection molding the sensor head 2 (see fig. 2) of the resin molded body. However, in fig. 10, a side view rather than a cross section is shown for the insulated electric wires 61a, 61b, 62a, and 62 b.

As shown in fig. 10, the mold 70 has an injection port 71 for injecting resin. The sensor head 2 can be molded by setting the cable 3, the sensor IC41, the IC42, and the bracket 60 connected in advance in the mold 70, injecting molten resin from the injection port 71 into the mold 70, and then solidifying the resin. The inlet 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 that hinders the flow of the resin in the mold 70. For example, when a plurality of insulated wires extending from the sheath end to the sensor IC41, IC42 are twisted with each other, the resin is difficult to flow between the twisted insulated wires.

Fig. 16 shows a connection state between a sensor IC and a cable that constitute the wheel speed sensor of the comparative example. The sensor ICs 41 and IC42 constituting the wheel speed sensor of the comparative example shown in fig. 16 are the same as the sensor ICs 41 and IC42 used in the present embodiment. However, the order of arrangement 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 on the cross section (not shown) of the cable 3, each of the insulated wires 61a and 61b connected to the upper side sensor IC41 is arranged at a diagonal position of a quadrangle, and each of the insulated wires 62a and 62b connected to the lower side sensor IC42 is arranged at another diagonal position of the quadrangle. That is, in the cross section of the cable 3, for example, the insulated wires 61a, 62a are arranged side by side in the first direction, and the insulated wires 62b, 61b are arranged side by side in the first direction. Also, in the cross section, the insulated wires 61a and 62b are juxtaposed in the second direction, and the insulated wires 62a, 61b are juxtaposed in the second direction.

In this case, four insulated electric wires 61a, 61b, 62a, and 62b extending from the jacket end to the sensor IC41, IC42 side in the sensor head cross and twist each other. When the cable 3 and the sensor ICs 41, 42 of the comparative example were connected to each other and set in a mold, and resin was injected to mold the sensor head, it was difficult for the resin to flow between the insulated electric wires 61a, 61b, 62a, and 62b twisted with each other. As a result, the sensor head is shaped with the insulated wires 61a, 61b, 62a, and 62b left a space therebetween. When a space is left 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 4 insulated wires are not exposed to the region directly below the inlet 71, a space is easily generated between the twisted insulated wires. In this case, the resin flowing into the mold 70 from the sprue 71 first contacts the surface (side surface) of the sheath 56, and then is filled to the sensor IC41, IC42 side along the extending direction of the sheath 56. That is, the resin is not injected into the 4 insulated wires near the end of the sheath, but advances along the extending direction of the sheath 56 and each insulated wire, and therefore, the pressure at which the resin enters between the insulated wires is smaller than the pressure of the resin that initially contacts the surface of the sheath 56 after the resin is injected. Therefore, a space is easily generated between the twisted insulated wires.

If a space remains in the sensor head, the core wire 50 may be corroded by moisture in the space or moisture entering the space from the outside, or the sensor IC41 or IC42 may be broken down. Therefore, from the viewpoint of improving the reliability of the rotation speed sensor, it is important to suppress a residual space in the sensor head caused by the twisting of the insulated wire.

In addition, when the insulated wires are twisted with each other, it is considered that the insulated wires are in a state of being pressed against each other. If injection molding is performed in this case, the insulator of the insulated wire is melted by the temperature of the resin, and thus the exposed plurality of core wires 50 may come into contact with each other to cause a short circuit. The more the number of insulated wires is, the more the problem becomes obvious.

From the viewpoint of the generation of the above-described space and the prevention of the occurrence of short circuit, it is conceivable to extend the length of the insulated wires from the terminals 57, 58 of the sensor IC41, IC42 to the end of the sheath. However, in this case, there is a problem that the size of the sensor head becomes large. That is, it is desirable that the length of the insulated wires from the terminals 57, 58 of the sensor ICs 41, IC42 to the jacket end in the front-rear direction be short.

In contrast, 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 adjacent to each other in parallel in the row direction (or column direction). Further, the insulated electric wires 62b, 62a are adjacent to each other side by side in this direction. Therefore, the insulated wires 61a, 61b are connected to the upper side sensor IC41 without twisting each other. Therefore, the resin injected in the injection molding step described with reference to fig. 10 smoothly flows around the respective insulated wires 61a and 61b extending in a straight line. Therefore, it is possible to suppress space from remaining in the sensor head 2 shown in fig. 4. Therefore, it is possible to suppress a decrease in the strength of the sensor head 2 caused by the presence of the space, and deterioration of the sensor head 2 caused by 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 with each other, even if the insulators of the insulated wires 61a and 61b are melted in the injection molding process, the core wires 50 can be prevented from being short-circuited with each other.

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

Further, in the present embodiment, by preventing the plurality of insulated wires from twisting each other, the length of the insulated wires 61a, 61b, 62a, and 62b from the terminals 57, 58 of the sensor IC41, IC42 to the sheath end can be shortened. Therefore, the sensor head 2 can be prevented from becoming large. This can reduce the manufacturing cost of the sensor head 2, i.e., the manufacturing cost of the rotation speed sensor. In addition, for example, when the size of the sensor 2 is set to the same size as that of a conventional rotation speed sensor having one sensor IC, it is not necessary to change the design of an external device of the sensor head 2, that is, a member holding the sensor head 2.

Further, since the insulated wires 61a, 61b do not need to be twisted with each other, the work of arranging the sensors IC41, IC42 and connecting the core wires 50 and the terminals 57, 58 becomes easy as shown in fig. 9. Therefore, the manufacturing cost of the rotation speed sensor can be reduced due to the improvement of the operability. Further, even if the length of the insulated wires from the terminals 57, 58 of the sensor IC41, IC42 to the jacket end portion is short, such work can be easily performed, and therefore, the sensor head 2 can be prevented from becoming large.

As a method of forming a cable by combining 4 insulated wires into 1, it is conceivable to prepare 2 twisted insulated wires formed by using 2 insulated wires as twisted wires and to form one cable by further bundling the 2 twisted insulated wires as twisted wires. However, this method makes the cable thick, making it difficult to bend. In contrast, in the present embodiment, one cable 3 is formed by bundling one twisted wire formed by crossing four insulated wires 61a, 61b, 62a, and 62b with each other and twisting. Thus, a thin and easily bendable cable 3 can be realized.

In the present embodiment, the insulated wires 61a and 61b connected to the upper sensor IC41 are not twisted, and the insulated wires 62a and 62b connected to the lower sensor IC42 are twisted. In contrast to this configuration, it can be said that the insulated wires 61a and 61b connected to the upper sensor IC41 are twisted, and the insulated wires 62a and 62b connected to the lower sensor IC42 are not twisted, and the same effect as that of the present embodiment can be obtained.

Here, the case where the sensor ICs 41 and 42 are independent individuals separated from each other is explained, but the magnetoresistance effect elements 41c and 42c (see fig. 4) may be encapsulated in the same resin to constitute one sensor IC. In other words, the magnetoresistance effect elements 41c, 42c and the resin may constitute one sensor IC having the four terminals 57, 58, and the sensor IC may be packaged in the sensor head 2.

(embodiment mode 2)

Next, the following description will be made of a case where the arrangement of insulated wires in a cable in which 4 insulated wires are bundled is examined to prevent twisting between the insulated wires exposed from the sheath in the sensor head and improve the reliability of the revolution speed sensor.

< construction of rotation speed sensor in the present embodiment >

As shown in fig. 11 to 15, the sensor head 2 and the cable 3 constituting the revolution speed sensor of the present embodiment are the same as those of embodiment 1 except that the arrangement of the insulated wires 62a and 62b connected to the lower sensor IC42 in the respective cables 3 is reversed as compared with embodiment 1.

That is, as shown in fig. 11, in the sensor head 2, the sensor ICs 41 and 42 are overlapped with each other in a state where both detection surfaces face upward. Also, a plurality of core wires 50 are connected to each of the terminals 57 and 58 of the sensor IC41 and the IC42, the plurality of core wires 50 passing through the cable 3 connected to the rear of the sensor head 2.

Fig. 13 is a bottom view of the lower sensor IC42 viewed from below, and the structure of the insulated wires 61a, 61b connected to the upper sensor IC41 and the upper sensor IC is the same as that shown in fig. 6. As shown in fig. 12 and 13, unlike embodiment 1, the insulated wires 62a and 62b do not cross each other or twist each other. As shown in fig. 14, this is because the respective positions of the insulated wires 62a and 62b are opposite to the respective positions of the insulated wires 62a and 62b shown in fig. 8.

Specifically, in a cross section in the radial direction of the cable 3 as shown in fig. 14, four insulated electric wires 61a, 61b, 62a, and 62b are located at, for example, four corners of a square. That is, the insulated wires 61a, 61b, 62a, and 62b are arranged in a matrix on the cross section. Here, in the cross section, the insulated wires 61a and 61b are lined up in the first direction, and the insulated wires 62a, 62b are lined up in the first direction. Further, in the cross section, the insulated wires 61a, 62a are arranged side by side in the second direction, and the insulated wires 61b, 62b are arranged side by side in the second direction.

Accordingly, the respective positions of the input terminal 41a, the output terminal 41b, the input terminal 42a, and the output terminal 42b and the respective positions of the insulated wires 61a, 61b, 62a, and 62b of 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 each connected to each other, it is possible to prevent two or more of the insulated wires 61a, 61b, 62a, and 62b from crossing between the terminals 57, 58 and the sheath end portions.

That is, the insulated wires 61a, 61b, 62a, and 62b are separated from each other without contacting 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 42 b. 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 the core wires 50 are connected to the respective sensor ICs 41 and 42, for example, as shown in fig. 15, the upper side sensor IC41 with the detection surface facing upward and the lower side sensor IC42 with the back surface facing upward are resistance-welded side by side. Thereafter, by changing the directions of the sensor ICs 41 and 42 by 90 degrees in opposite directions, the detection surfaces of the sensor ICs 41 and 42 can be oriented in the same direction to overlap the sensor ICs 41 and 42.

< effects of the present embodiment >

In the present embodiment, as shown in fig. 14, among the insulated wires 61a, 61b, 62a, and 62b arranged in a rectangular shape in the cross section of the cable 3, the insulated wires 61a and 61b are arranged in the row direction (or column direction) and adjacent to each other, and the insulated wires 62a and 62b are also arranged in this direction and adjacent to each other. Therefore, the insulated electric wires 61a, 61b, 62a, and 62b can be connected to the sensor ICs 41, IC42 without twisting each other. Therefore, in the injection molding step described with reference to fig. 10, the resin easily flows around the respective insulated wires 61a, 61b, 62a, and 62b extending linearly, and therefore, a phenomenon in which a space remains in the sensor head 2 shown in fig. 11 can be suppressed. Therefore, it is possible to suppress a decrease in the strength of the sensor head 2 caused by the presence of the space, and deterioration of the sensor head 2 caused by moisture in the space.

In the present embodiment, unlike embodiment 1, the insulated wires 61a and 61b are not twisted, and the insulated wires 62a and 62b are not twisted with 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 arrangement in the first direction of the insulated wires 61a connected to the input terminal 41a and the insulated wires 61b connected to the output terminal 41b is the same as the order of arrangement in the first direction of the insulated wires 62a connected to the input terminal 42a and the insulated wires 62b connected to the output terminal 42 b. Therefore, when the sensor ICs 41 and the IC42 having the same structure and function are overlapped with the detection faces facing the same direction, the insulated wires 61a, 61b, 62a, and 62b are connected to the terminals 57, 58 without crossing each other. Therefore, the position where the resin is hard to flow due to the twisting of the insulated wire can be eliminated, and therefore, in the present embodiment, the quality of the resin mold can be improved more than in embodiment 1.

Also, 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, short circuits between the core wires 50 can be suppressed.

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

Further, in the present embodiment, by preventing the plurality of insulated wires from twisting each other, the length of the insulated wires 61a, 61b, 62a, and 62b from the terminals 57, 58 of the sensor IC41, IC42 to the sheath end can be shortened. Therefore, the sensor head 2 can be prevented from becoming large.

Further, since it is not necessary to twist the insulated wires 61a, 61b, 62a, and 62b with each other, the operation of connecting the core wires 50 and the terminals 57 and 58 with the array sensors IC41 and IC42 becomes easy as shown in fig. 15. Therefore, the manufacturing cost of the rotation speed sensor can be reduced. In addition, even if the length of the insulated wires from the terminals 57, 58 of the sensor IC41, IC42 to the jacket end is short, since such an operation becomes easy, it is possible to prevent the sensor head 2 from becoming large.

Here, the case where the sensor ICs 41 and 42 are independent individuals separated from each other has been explained, but the magnetoresistance effect elements 41c and 42c (see fig. 4) may be encapsulated in the same resin to constitute one sensor IC. In other words, the magnetoresistance effect elements 41c, 42c and the resin may constitute one sensor IC having the four terminals 57, 58, and the sensor IC may be packaged in the sensor head 2.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the novel idea of the invention.

For example, the detection element included in the sensor IC built in the sensor head may be an anisotropic magnetoresistance effect element (AMR (inverse magnetoresistance effect element), a tunnel magnetoresistance effect element (TMR (tunnel magnetoresistance effect element)), or the like, or may be a hall element.

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

The utility model discloses also can be applied to rotational speed sensor except that wheel speed sensor, have the same effect with the aforesaid under the condition of using.

Claims (10)

1. A rotational speed sensor, comprising:

a sensor head including a sensor holding portion and a cable holding portion;

a cable extending from the cable holding portion; and

a first sensor IC and a second sensor IC embedded in the sensor holding portion and outputting an electric signal corresponding to a change in the magnetic field,

the first sensor IC has a first detection surface, a first back surface on the opposite side of the first detection surface, 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, a third terminal, and a fourth terminal,

the above-mentioned cable includes: a first insulating wire electrically connected to the first terminal; a second insulated wire electrically connected to the second terminal; a third insulated wire electrically connected to the third terminal; a fourth insulated wire electrically connected to the fourth terminal; and a sheath for collectively covering the first insulated wire, the second insulated wire, the third insulated wire and the fourth insulated wire,

the first insulated wire, the second insulated wire, the third insulated wire and the fourth insulated wire form twisted strands,

in a cross section along a radial direction of the cable, the first insulated wire and the second insulated wire are arranged in a 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 in a second direction intersecting the first direction.

2. A rotation speed sensor according to claim 1,

the first back surface and the second detection surface are opposed to each other,

the first terminal and the third terminal partially overlap each other in a plan view,

the second terminal and the fourth terminal partially overlap each other in a plan view.

3. A rotation speed sensor according to claim 1,

in the cross section in 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.

4. A rotation speed sensor according to claim 2,

in the cross section in 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.

5. A rotation speed sensor according to any one of claims 1 to 4,

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 an output terminal of the second sensor IC.

6. A rotation speed sensor according to any one of claims 1 to 4,

the sensor head is made of resin.

7. A rotation speed sensor according to claim 3 or 4,

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.

8. A rotation speed sensor according to any one of claims 1 to 4,

each of the first sensor IC and the second sensor IC has a magnetoresistance effect element as a detection element.

9. A rotation speed sensor according to any one of claims 1 to 4,

separators are provided between the first insulated wire and the second insulated wire and between the third insulated wire and the fourth insulated wire, respectively.

10. A rotation speed sensor according to any one of claims 1 to 4,

the first sensor IC and the second sensor IC operate simultaneously.

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