JP2007230413A - Torque sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mounting structure for a torque sensor of an electric power steering device or the like with sufficient space efficiency capable of sufficiently ensuring impact absorption stroke of an impact absorption mechanism. <P>SOLUTION: A circuit board of a control module CM is arranged perpendicular to an axial direction of an input shaft and an output shaft. In an output terminal 15a of a detection coil 15 of the torque sensor, since a distal end is bent to an L shape and is formed perpendicular to a through hole 18 of the circuit board of the control module CM, the detection coil and the control module can be easily and directly connected. When a gear box mounted with the control module CM is arranged in a narrow engine room, the space efficiency is sufficient and the impact absorption stroke of the impact absorption mechanism can be sufficiently ensured. As the output terminal 15a of the detection coil 15, a round pin of a round cross section is used, and a bending punch and a die are used for bending of a distal end and machining is accurately performed. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to a torque sensor that detects torque by twisting between an input shaft and an output shaft, and more particularly to a structure of a torque sensor applied to an electric power steering device for a vehicle.

  An electric power steering device for a vehicle detects a steering torque generated in a steering shaft connecting a steering handle and a steering mechanism, and outputs a motor based on the detected steering torque and a vehicle speed detected by a vehicle speed sensor. And the driving force of the motor is transmitted to the steering shaft by a gear or other speed reduction mechanism to appropriately assist the steering torque of the steering wheel.

  In such a control device for an electric power steering device, a torque detection circuit for detecting steering torque, a control circuit for controlling the magnitude of motor current based on the detected steering torque, and control of motor current output from the control circuit A plurality of circuits such as a motor drive circuit that drives a motor with a duty ratio determined based on the value is required, and each circuit is integrated into a plurality of circuit modules such as a sensor module, a control module, and a power module, and steering Although it was individually arranged in the vicinity of the gear box of the apparatus, there was a disadvantage that the number of parts and the number of assembly steps increased. For this reason, there are some in which these plural circuit modules are further integrated and attached to the gear box of the steering device.

  On the other hand, some torque sensors use a detection coil that detects, as an inductance change, a magnetic resistance that changes according to the torsion angle of the torsion bar connected to the steering shaft, and uses a gear box configured as described above. In such a case, a configuration is known in which a coil yoke accommodating a detection coil is disposed close to the gear box and a terminal of the detection coil is connected to a circuit module (see Patent Document 1).

  FIG. 5 is a cross-sectional view of a gear box having the above-described configuration, and FIG. 6 is an enlarged cross-sectional view of a connection portion that connects the terminal of the detection coil to the circuit module.

  With reference to FIG.5 and FIG.6, the structure and operation | movement of a torque detection part are demonstrated easily. An input shaft 102 and an output shaft 103 connected via a torsion bar 104 are disposed inside the housing 101, and the output shaft 103 is rotatably supported by ball bearings 105a and 105b. The input shaft 102, the torsion bar 104, and the output shaft 103 are arranged coaxially, the input shaft 102 and the torsion bar 104 are spline-coupled, and the torsion bar 104 and the output shaft 103 are pin-coupled.

  A worm wheel 106 is coupled to the output shaft 103, and the worm wheel 106 meshes with a worm 107 b coupled to the shaft 107 a of the electric motor 107.

  The sleeve 102A fixed to the end of the input shaft 102 has a cylindrical member provided with a plurality of windows 108a and 108b made of a nonmagnetic material such as aluminum at the end and arranged at equal intervals in the circumferential direction. 108 is fixed. On the other hand, the output shaft 103 is made of a magnetic material, and a plurality of convex portions 103A and 103B are formed at positions corresponding to the plurality of windows 108a and 108b of the cylindrical member 108. In addition, coil yokes 109 </ b> A and 109 </ b> B including detection coils L <b> 1 and L <b> 2 are disposed coaxially on the outer periphery of the cylindrical member 108 inside the housing 101.

  In the above configuration, when a rotational force acts on the input shaft 102, it is transmitted to the output shaft 103 via the torsion bar 104, and twisted in the torsion bar 104, thereby causing a plurality of windows 108 a of the cylindrical member 108 on the input shaft side. 108b and the plurality of convex portions 103A and 103B on the output shaft side, and the plurality of magnetic materials exposed through the plurality of windows 108a and 108b of the cylindrical member on the input shaft 102 side made of a nonmagnetic material are generated. The areas of the convex portions 103A and 103B on the output shaft 103 side increase or decrease, and the inductances of the detection coils L1 and L2 increase or decrease. By detecting changes in the inductances of the detection coils L1 and L2, it is possible to detect the magnitude of torsion occurring in the torsion bar 104, that is, the magnitude of torque acting on the input shaft 102.

A connection portion for connecting the terminal of the detection coil to the circuit module will be described with reference to FIG. Reference numeral 114 denotes a circuit board of the circuit module, and 115 and 116 denote terminal pins of the detection coils L1 and L2. As is apparent from FIG. 6, the terminals of the detection coil and the circuit board are arranged in parallel to the axial direction of the input shaft and the output shaft. This is due to the structure of the detection coil and the circuit board.
JP-A-9-1012122.

  However, if the circuit board is arranged parallel to the axial center direction of the input shaft and the output shaft as described above, the axial length of the input shaft and the output shaft of the gear box becomes long, and the gear box is arranged in a narrow engine room. When it is required to do so, it is not only disadvantageous in terms of space, but also disadvantageous in that it is difficult to ensure a sufficient shock absorbing stroke of the shock absorbing mechanism that is required to be installed in the middle of the steering shaft. is there. The present invention aims to solve the above problems.

  The present invention solves the above-mentioned problems, and the invention according to claim 1 is a torque sensor for detecting torque by twisting between an input shaft and an output shaft, the detection coil for detecting torque, and the detection coil A control module for processing a detection signal output from the control module, wherein the circuit board of the control module is arranged perpendicular to the axial direction of the input shaft and the output shaft arranged coaxially, and the output terminal of the detection coil Is a torque sensor characterized in that its tip is arranged perpendicular to the circuit board of the control module.

  The output terminal of the detection coil includes a base connected to the detection coil and a tip connected to the circuit board of the control module, and the tip is bent at a right angle with respect to the base and formed in an L shape. It is assumed that

  The output terminal of the detection coil may be a round pin having a round cross section.

  According to a fourth aspect of the present invention, there is provided a torque sensor for an electric power steering apparatus, wherein a detection coil that detects a twist between an input shaft and an output shaft arranged coaxially generated by a steering torque as a change in inductance, A control module for processing a detection signal output from the detection coil, the circuit board of the control module is arranged perpendicular to the axial direction of the input shaft and the output shaft, and the output terminal of the detection coil is The torque sensor of the electric power steering apparatus, characterized in that a tip portion thereof is arranged perpendicular to the circuit board of the control module.

  The output terminal of the detection coil includes a base connected to the detection coil and a tip connected to the circuit board of the control module, and the tip is bent at a right angle with respect to the base and formed in an L shape. It is assumed that

  The output terminal of the detection coil may be a round pin having a round cross section.

  Further, the output terminal of the detection coil may be formed in an L-shape by bending the tip at a right angle to the base using a bending punch and a die.

  As described above, the torque sensor according to the first aspect of the invention is space efficient because the circuit board of the control module is arranged perpendicular to the axial direction of the input shaft and the output shaft. When the output terminal of the detection coil of the torque sensor is bent in an L shape and is perpendicular to the circuit board of the control module, the detection coil and the control module can be directly connected directly. Can do.

  In the torque sensor of the electric power steering apparatus according to the fourth aspect of the present invention, the circuit board of the control module is arranged perpendicular to the axial direction of the input shaft and the output shaft. Sufficient shock absorption stroke of the absorption mechanism can be secured. And since the output terminal of the detection coil of the torque sensor is bent perpendicularly to the circuit board of the control module with the tip end bent in an L shape, the detection coil and the control module can be easily and directly connected. it can.

  In addition, by using a round pin with a round cross section for the output terminal of the detection coil, when using a bending punch and die for bending the tip, the round pin comes into line contact with the die, so the bending process can be performed accurately. It can be carried out.

  Hereinafter, an embodiment in which the present invention is applied to an electric power steering apparatus will be described. FIG. 1 is an exploded perspective view of main components of the electric power steering apparatus, and FIG. 2 is a perspective view illustrating a torque detection coil and members related thereto. Note that the steering shaft, the input and output shafts connected to the steering shaft, the speed reduction mechanism, and the like are not shown in order to avoid complicated drawings.

  1 and 2, reference numeral 11 denotes a gear box of the steering device, and 12 denotes a motor. Although not shown in the figure, the gear box 11 has a cylindrical input shaft connected to the steering shaft, a torsion bar coaxially disposed therein, and a torsion bar coaxially disposed with the input shaft. The output shaft is rotatably supported through the arrow a, and a worm wheel (not shown) is coupled to the output shaft. The lower right side of the arrow a is the input shaft side, and the upper left side is the output shaft side. Since the configuration of the input shaft, the torsion bar and the output shaft, and the configuration of the torque sensor are known configurations similar to the conventional configuration described with reference to FIGS. 5 and 6, detailed description thereof will be omitted.

  The flange 12a of the motor 12 is configured to be fixed to the motor mounting surface 11a of the gear box 11, and the shaft of the motor 12 is not shown but can be coupled to the worm shaft housed in the gear box 11. It is configured. Needless to say, the worm and the worm wheel are configured to maintain an appropriate meshing state.

  With reference to FIG.1 and FIG.2, the structure and arrangement | positioning of each member are demonstrated. The upper half of the gear box 11 is formed in a box-shaped rectangular parallelepiped 11b in which a worm is accommodated. The gear box 11 is more than the axis of the motor shaft connected to the worm shaft as seen from the meshing portion between the worm and the worm wheel. A first plane 11b1 on the outer side and a second plane 11b2 on the input shaft side that intersects the first plane 11b1 at right angles to the L-shape are formed. The first plane 11b1 and the second plane 11b2 Is used as a mounting surface of a circuit module to be described later.

  Further, the first flat surface 11b1 is seen from the meshing portion between the worm and the worm wheel, and is located outside the shaft center of the motor shaft and from the meshing portion intersecting the plane including the meshing portion and the motor shaft axis. It is the plane that is farthest away.

  The lower half of the gear box 11 is formed in a semicircular box 11c in which a worm wheel is accommodated, and is formed integrally with a box-shaped rectangular parallelepiped 11b. Although not shown on the side surface of the semicircular box 11c, a cylinder for holding a torque sensor for detecting a steering torque by torsion of a torsion bar that couples the input shaft and the output shaft and a ball bearing for the input shaft. 11d is attached, and the output terminal 15a of the torque detection coil 15 of the torque sensor is exposed to an opening 11e provided close to the second flat surface 11b2 of the cylindrical member 11d.

  The module mounting member 13 is a member that is mounted to face the two surfaces of the first plane 11b1 and the second plane 11b2 of the gear box 11 arranged in the L-shape, and is made of synthetic resin. The whole is formed in an L shape. The module mounting member 13 includes a plurality of circuit modules, that is, a power module PM constituting a power circuit for driving a motor composed of a switching transistor, a control module CM incorporating a control circuit and a torque detection circuit, a power circuit, and other circuits. A frame module FM in which elements are incorporated is assembled.

  The module mounting member 13 is provided with a signal line connector 14a for connecting a control signal line to each part of the vehicle body, a power connector 14b for connecting a driving power source (battery), and a motor terminal connector 14c for connecting a motor terminal. In addition, a wiring member for connecting circuit modules such as the power module PM, the control module CM, and the frame module FM mounted on the module mounting member 13 is incorporated, and the circuit module is mounted on the module mounting member 13. By mounting, the connection between the circuit modules is completed, and the connection with the signal line connector 14a, the power supply connector 14b, and the motor terminal connector 14c is also completed.

  An input shaft connected to a steering shaft, a torsion bar, and an output shaft are rotatably supported inside the gear box 11, and a worm wheel constituting a speed reduction mechanism is coupled to the output shaft. The meshing worm is also rotatably supported by a bearing disposed in the gear box 11.

  Further, when the motor 12 is fixed to the motor mounting surface 11 a of the gear box 11, the shaft of the motor 12 is coupled to the worm supported inside the gear box 11, and the motor 12 drives the worm and the worm wheel. The output shaft is assembled so as to be rotationally driven through a reduction mechanism.

  The circuit modules of the power module PM, the control module CM, and the frame module FM are finished so that they can be assembled, and the power supply terminal 12d of the motor 12 can be assembled to a motor terminal connector 14c provided in the frame module FM. It is finished.

  The control module CM is attached to the module attachment member 13 located outside the frame module FM. The control signal terminal of the control module CM is electrically connected to the corresponding control signal terminal of the frame module FM, and is exposed to the opening 11e close to the second plane 11b2 on the input shaft side of the gear box 11. The output terminal 15a of the detection coil 15 of the torque sensor is also electrically connected to the corresponding terminal of the control module CM.

  The motor 12 is fixed to the motor mounting surface 11a of the gear box 11 with screws. The rotating shaft of the motor 12 is coupled to a worm shaft housed in the gear box 11, and the power supply terminal of the motor 12 is electrically connected by being fixed to the motor terminal connector 14c of the frame module FM.

  Next, the control module CM and the output terminal 15a of the detection coil 15 of the torque sensor, which are the features of the present invention, will be described.

  The circuit board of the control module CM attached to the module attachment member 13 is arranged on a plane perpendicular to the axes of the input shaft, the torsion bar, and the output shaft arranged coaxially. On the other hand, the detection coil 15 of the torque sensor is disposed around the output shaft disposed inside the cylindrical member 11d, and the configuration of the torque sensor itself is the conventional configuration described above with reference to FIGS. It is the same.

  The output terminal 15a of the detection coil 15 of the torque sensor is formed in an L shape including a base portion 15a1 extending perpendicularly from the outer peripheral surface of the detection coil 15 and a tip portion 15a2 bent at a right angle to the base portion 15a1. 3) and the tip portion 15a2 is formed to be perpendicular to the circuit board of the control module CM. The output terminal 15a is a round pin having a round cross section.

  According to this configuration, the tip end portion 15a2 of the round cross-section pin can be vertically inserted into the through hole 18 that is the connection portion of the circuit board of the control module CM, and the detection coil 15 and the control module CM can be easily and directly connected. Can be connected (see FIG. 1).

  Next, the bending process of the output terminal of the detection coil will be described with reference to FIGS. FIG. 3 is a front view for explaining bending of the output terminal 15a of the detection coil, and FIG. 4 is a cross-sectional view taken along the line AA of FIG.

  In FIG. 3, 21 is a base plate for fixing the detection coil 15, 22 is a bending punch, and 23 is a die for supporting the output terminal 15a. The detection coil 15 is fixed on the base plate 21, and the base portion 15a1 of the output terminal 15a is supported by the die 23 from below. Next, the bending punch 22 is pushed down along the side surface of the die 23 to bend the tip portion 15a2 of the output terminal 15a. The tip portion 15a2 of the output terminal 15a indicated by a chain line in FIG. 3 is formed at a tip portion that is bent at a right angle to the base portion 15a1, as indicated by a thick black solid line.

  At this time, since the cross section of the output terminal 15 a is a round pin, when the base portion 15 a 1 of the output terminal 15 a is supported by the die 23 from below, the base portion 15 a 1 of the output terminal 15 a The surface is in line contact with the die plane, and since the contact surface is small, it can be bent with high accuracy.

  As mentioned above, although the embodiment which applied the torque sensor of this invention to the electric power steering device was described, the torque sensor of this invention is not limited to the application to the electric power steering device, and the torque of other mechanical devices. Needless to say, it can be applied to sensors.

  Since the torque sensor control module of the present invention is arranged perpendicular to the axial direction of the input shaft and the output shaft, when the gear box on which the control module is mounted is arranged in a narrow space, for example, in the engine room, the space Efficiency is good. Further, when applied to the electric power steering apparatus, a sufficient shock absorbing stroke of the shock absorbing mechanism can be secured. And since the output terminal of the detection coil of the torque sensor is bent perpendicularly to the circuit board of the control module with the tip end bent in an L shape, the detection coil and the control module can be easily and directly connected. it can.

The perspective view which decomposed | disassembled the main components of the electric power steering apparatus. The perspective view explaining the torque detection coil of the electric power steering apparatus shown in FIG. 1, and the member relevant to this. The front view explaining the bending process of the output terminal of a detection coil. Sectional drawing along the AA line of FIG. 3 explaining the bending process of the output terminal of a detection coil. Sectional drawing explaining an example of a structure of the principal part of the conventional electric power steering apparatus. Sectional drawing which expanded the connection part of the circuit board of the conventional electric power steering apparatus shown in FIG. 5, and the detection coil of a torque sensor.

Explanation of symbols

11 Gearbox (Steering gearbox)
11a Motor mounting surface 11b Box-shaped rectangular parallelepiped 11b1 First plane 11b2 Second plane 11c Semicircular box 11d Cylindrical member 11e Opening 12 Motor 13 Module mounting member 14a Signal line connector 14b Power supply connector 14c Motor terminal connector
15 Torque detection coil of torque sensor 15a Output terminal of torque detection coil 15a1 Base (base of output terminal of torque detection coil)
15a2 Tip (tip of the output terminal of the torque detection coil)
18 Through hole (circuit board connection)
21 base plate
22 Bending punch 23 Die PM Power module CM Control module FM Frame module

Claims (7)

A torque sensor for detecting torque by twisting between an input shaft and an output shaft,
A detection coil for detecting torque;
A control module for processing a detection signal output from the detection coil,
The circuit board of the control module is arranged perpendicular to the axial direction of the input shaft and the output shaft arranged coaxially,
The torque sensor, wherein the output coil has an output terminal arranged perpendicularly to the circuit board of the control module. The output terminal of the detection coil is composed of a base part connected to the detection coil and a tip part connected to the circuit board of the control module, and the tip part is bent at a right angle to the base part and formed in an L shape. The torque sensor according to claim 1, wherein: The torque sensor according to claim 1, wherein the output terminal of the detection coil is a round pin having a round cross section. A torque sensor for an electric power steering device,
A detection coil that detects torsion between an input shaft and an output shaft that are coaxially disposed due to steering torque as a change in inductance;
A control module for processing a detection signal output from the detection coil,
The circuit board of the control module is disposed perpendicular to the axial direction of the input shaft and the output shaft,
The torque sensor of the electric power steering apparatus, wherein an output terminal of the detection coil has a tip portion disposed perpendicular to a circuit board of the control module. The output terminal of the detection coil is composed of a base part connected to the detection coil and a tip part connected to the circuit board of the control module, and the tip part is bent at a right angle to the base part and formed in an L shape. The torque sensor of the electric power steering apparatus according to claim 4, wherein The torque sensor of the electric power steering apparatus according to claim 4, wherein the output terminal of the detection coil is a round pin having a round cross section. 2. The torque sensor according to claim 1, wherein the output terminal of the detection coil is formed in an L shape by bending a tip portion thereof at a right angle with respect to a base portion using a bending punch and a die. Item 5. A torque sensor for an electric power steering apparatus according to Item 4.

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