JP2016011899A - Attachment device of torque sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a torque sensor to be attached to an output shaft together with a case and enable the torque sensor to be simply and accurately attached without requiring proficiency primarily for the adjustment of a torque sensor.SOLUTION: A torque sensor is attached to the output shaft of a steering mechanism by an attachment device F provided with an annular base part Fa, a cylindrical part Fb integrally formed on a rear side surface of the base part Fa, and a first notch part Fc formed by partially notching a rear end surface of the cylindrical part Fb; and a second notch part Fd formed on the rear end surface of the cylindrical part Fc by attaching a step D projected from a left end edge of the first notch part Fc to the rear side. When a main body of the case of the torque sensor is fitted into the cylindrical part Fb so as to be pushed forward, a grip of the case abuts against the first notch part Fc, and after that, the pressing of the case is released, and the case is pushed backward by a portion of a step D of the attachment device F, and then, slightly rotated to the left. Then, the grip of the case abuts against the second notch part Fd so as to be positioned, and thereby completing the attachment.

Description

  The present invention relates to a torque sensor mounting device for mounting a torque sensor in an electric power steering device that generates an auxiliary steering torque according to a steering torque applied to a steering wheel by a power steering motor and transmits the auxiliary steering torque to an output shaft of a steering mechanism. About.

  Conventionally, an electric power steering device detects a steering torque applied to a steering wheel by a torque sensor, generates an auxiliary steering torque corresponding to the detected steering torque by a power steering motor, and transmits it to an output shaft of a steering mechanism. (See Patent Document 1).

  A torque sensor used in such an electric power steering device is usually a case, a stator assembly that is housed in the case and is externally fitted to an input shaft connected to a steering wheel, and different magnetic poles alternately in the circumferential direction. And a magnetic flux based on a rotation difference of the stator assembly with respect to the rotor assembly, which is accommodated in the stator assembly and fitted inside the output shaft of the steering mechanism and disposed inside the stator assembly. Rotation that occurs between the input shaft and the output shaft by twisting a torsion bar with both ends fixed to the input shaft and the output shaft by the steering force applied to the steering wheel. The difference is detected as a steering torque by the magnetic sensor unit.

WO 2005/049406 (Specification, page 1, line 25 to page 3, line 9 and FIG. 8)

  By the way, in a conventional torque sensor, a stator assembly in which a rotor assembly is provided is accommodated in one case, and the rotor assembly and the stator assembly are accommodated in a housing and integrated with each of the input shaft and the output shaft. When the torque sensor is attached to the tube in which the input shaft and output shaft are housed, and then the tube is press-fitted into the spacer attached to the device housing, it is fitted to the input shaft and output shaft respectively. There is a problem that the work efficiency is low and the mounting accuracy is also low.

  Therefore, it is possible to attach a spacer to the device housing that houses the output shaft first, and then attach the tube after the torque sensor is fitted to the output shaft, but the torque sensor is fitted to the output shaft. When the actuator is pushed in the axial direction of the output shaft, the rotor assembly is not arranged in the stator assembly but only on the inner side due to the structure of the torque sensor. When the rotor assembly is fitted into the output shaft, the stator Since the assembly can move in the axial direction (thrust direction) by a predetermined stroke amount, it is necessary to ensure a predetermined gap in the thrust direction between the torque sensor and the spacer according to the movement amount of the stator assembly. However, if such a gap is provided, the torque sensor will be rattled by the gap after assembly and noise will be generated. There is a problem that leads to.

  On the other hand, in the above-described torque sensor in Patent Document 1, the components of the torque sensor are separated into the shaft side and the device housing side and pre-assembled, and then the components on the shaft side and the device housing side are combined. However, it is very difficult to prevent the oil seal from being damaged at the time of coalescence, and there is a problem that there are many restrictions such that adjustment of the torque sensor must be performed after the coalescence and adjustment is required.

  It is an object of the present invention to attach the torque sensor to the output shaft together with the case, and does not require skill for adjusting the torque sensor, and allows the torque sensor to be easily and accurately attached.

  In order to achieve the above-described object, the torque sensor mounting device of the present invention is an electric power that generates an auxiliary steering torque according to a steering torque applied to a steering wheel by a power steering motor and transmits it to an output shaft of a steering mechanism. A torque sensor provided in a steering device for detecting the operation torque, the input shaft connected to a steering wheel and connected to a steering wheel that is accommodated in the case and is movable relative to the case A stator assembly that is externally fitted to the output shaft, and an annular magnet in which different magnetic poles are alternately arranged in the circumferential direction, and are externally fitted to the output shaft or the input shaft and are relatively shafts relative to the stator assembly. A rotor assembly disposed inside the stator assembly so as to be movable in a direction; A torsion bar that is housed in a motor and detects a magnetic flux based on a rotation difference of the stator assembly relative to the rotor assembly, and a torsion bar having both ends fixed to the input shaft and the output shaft, respectively, is added to the steering wheel. In a torque sensor mounting apparatus for mounting a torque sensor that detects a rotation difference generated between the input shaft and the output shaft as the steering torque by the magnetic sensor unit by being twisted by a steering force that is generated. An annular base part rotatably mounted on the outside of the output shaft and fitted with the case, a cylindrical part integrally formed on one side of the base part, and a part cut into an end surface of the cylindrical part. A first portion that is formed to be abutted and abutted with the abutting portion of the case when the case is pushed into the cylindrical portion. The notch and the step formed in the part of the end surface of the cylindrical part with a step projecting from the edge of the first notch to the opposite side of the pushing direction of the case are inserted into the cylindrical part of the case. A second notch portion for positioning in the axial direction by contacting the contact portion by rotating the case after completion, and the step is the rotor assembly with respect to the case of the torque sensor or the It is set according to the amount of movement of the stator assembly (claim 1).

  According to the first aspect of the present invention, when mounting is performed in a state in which the stator assembly and the rotor assembly inserted therein are accommodated in the case and the torque sensor is assembled, the case can be rotated outside the output shaft. The case is pushed into the inside of the cylindrical portion until the abutting portion of the case of the torque sensor comes into contact with the first notch portion of the end surface of the cylindrical portion integrally formed with the attached annular base portion, and the rotor assembly outputs, for example, It is fixed at a predetermined position on the shaft. Thereafter, the case is returned and rotated in the axial direction by the level difference, and the contact portion of the case is brought into contact with the second cutout portion to be positioned.

  At this time, the step between the first notch and the second notch is set according to the amount of movement (stroke amount) in the axial direction (thrust direction) of the rotor assembly with respect to the case. The case is pushed into the inside of the cylindrical portion until the abutting portion of the case comes into contact, and after the pushing is released, the case is returned to the direction opposite to the pushing direction by a level difference and then rotated so that the abutting portion of the case contacts the second notch. When the contact is made, the torque sensor is attached to the output shaft in a state where the rotor assembly secures an appropriate clearance from the case and the stator assembly. Note that the stator assembly may be externally fitted to the output shaft, and in this case, the torque sensor is attached to the output shaft in a state where the stator assembly secures an appropriate gap from the case and the rotor assembly.

  Therefore, it is not a blind work in an invisible state, but can be easily attached to the output shaft together with the case with the torque sensor assembled, and the torque sensor rotor assembly ensures an appropriate clearance from the case and the stator assembly. This makes it possible to attach the torque sensor to the output shaft and eliminates the need to adjust the torque sensor. Can be performed accurately.

It is sectional drawing of the electric power steering apparatus in one Embodiment of this invention. It is a perspective view of the torque sensor in FIG. It is a perspective view of the attachment apparatus in FIG. It is a front view of the attachment apparatus of FIG. It is sectional drawing in the XX line of FIG. It is sectional drawing in the YY line | wire of FIG.

  An embodiment of the present invention will be described in detail with reference to FIGS. In the present embodiment, front, rear, left, and right mean front, rear, left, and right in the vehicle traveling direction.

  The electric power steering apparatus in the present embodiment is configured as shown in FIG. That is, a solid input shaft 2 connected to a steering wheel (not shown) is rotatably accommodated in a steering column tube 1 via a bearing 3 and the front end of the tube 1 is fitted in a housing 4. The rear end of a hollow output shaft 6 of a steering mechanism (not shown) that is rotatably accommodated via a bearing 5 is inserted into a recess 2 a on the front end surface of the input shaft 2, and is accommodated in the output shaft 6. Both ends of the torsion bar 7 are fixed to the front end of the input shaft 2 and the front end of the output shaft 6, respectively.

  Then, the torque sensor 10 is attached to the outer periphery of the front end portion of the output shaft 6 by the attachment device F, and the steering torque applied to the steering wheel by the driver's operation is detected by the torque sensor 10, and the assist corresponding to the detected steering torque Steering torque is generated by a power steering motor 11 assembled to the housing 4, and is connected to a worm gear 12 connected to the motor shaft and a gear 13 that is externally fitted to the central portion of the output shaft 6 and meshed with the worm gear 12. The auxiliary steering torque generated by the power steering motor 11 is transmitted to the output shaft 6.

  By the way, the torque sensor 10 is configured as shown in FIG. 6, and a case 10c having a shape in which a handle 10b is attached to a main body 10a having a shape obtained by removing the inner periphery of a cylinder, and a case 10c accommodated in the case 10c. An annular stator assembly that is disposed so as to be relatively movable and is fitted on the input shaft 2 connected to the steering wheel, and an annular magnet in which different magnetic poles are alternately arranged in the circumferential direction are provided. An annular rotor assembly that is fitted on the output shaft 6 of the steering mechanism and is disposed inside the stator assembly so as to be axially movable relative to the stator assembly; and a rotor assembly housed in the case 10c. And a magnetic sensor unit such as a Hall element for detecting a magnetic flux based on a rotation difference of the stator assembly with respect to the motor. Here, the rotor assembly of the torque sensor 10 is not only fitted inside the stator assembly so as to be movable, but is not fitted. When the rotor assembly is fitted to the output shaft 6, the rotor assembly is arranged. Is structured to be movable by a predetermined stroke amount in the axial direction (thrust direction).

  Then, when the torsion bar 7 is twisted by a steering force applied to the steering wheel, a rotation difference generated between the input shaft 2 and the output shaft 6 is detected as a steering torque by the magnetic sensor unit.

  Next, a characteristic configuration of the attachment device F according to the present invention will be described with reference to FIGS. 3 to 6. The mounting device F is configured as shown in FIG. 3 in appearance, and has an annular base part Fa, a cylindrical part Fb integrally formed on the rear side surface of the base part Fa, and a part of the end face of the cylindrical part Fb. A first notch Fc formed at the end, and a second notch Fd formed at a part of the end surface of the cylindrical part Fc with a step D protruding backward from the left end edge of the first notch Fc. ing. At this time, the widths (dimensions) W1 and W2 in the circumferential direction of the first cutout portion Fc and the second cutout portion Fd are the width w in the circumferential direction of the main body 10a of the handle 10b of the torque sensor 10 (see FIG. 2). The step D is set to the same dimension as the stroke amount in the axial direction (thrust direction) of the rotor assembly with respect to the case 10c of the torque sensor 10.

  As shown in FIG. 1, a base Fa is rotatably mounted on the outside of the output shaft 6 through a bearing 15, and the cylindrical portion Fb is connected to a cylindrical fitting portion 1 b formed on the flange portion 1 a at the front end of the tube 1. It is externally fitted and fixed to the flange portion 1a by a bolt 1c, and the mounting device F is disposed outside the center portion of the output shaft 6 from the rear end portion. At this time, when the cylindrical portion of the case 10c of the torque sensor 10 is fitted into the cylindrical portion Fb from the rear end surface side of the cylindrical portion Fb and further pushed forward, the handle 10b of the case 10c, which is a contact portion in the present invention, is moved. After contacting the first notch Fc and the handle 10b contacting the first notch Fc, the pushing of the case 10c is released, and the case 10c is moved backward by the amount corresponding to the step D of the mounting device F (reverse to the pushing direction ( When the handle 10b of the case 10 is brought into contact with the second notch Fd and is sandwiched between the flange 1a, the torque sensor 10 is positioned. This completes the mounting of the torque sensor 10 to the mounting device F.

  Here, the step D between the first notch portion Fc and the second notch portion Fd of the attachment device F corresponds to the amount of movement (stroke amount) in the axial direction (thrust direction) of the rotor assembly of the torque sensor 10 relative to the case 10c. Therefore, when the torque sensor 10 is completely attached, the torque sensor 10 is attached to the output shaft 6 with the rotor assembly of the torque sensor 10 securing an appropriate gap from the case 10c and the stator assembly.

  Therefore, according to the above-described embodiment, the torque sensor 10 can be easily attached to the output shaft 6 together with the case 10c in a state where the torque sensor 10 is assembled. The torque sensor 10 can be attached to the output shaft 6 in a state in which an appropriate gap is secured from the case and the stator assembly.

  In addition, since the torque sensor 10 is attached in an assembled state instead of being attached in a separated state, there is no need to worry about damaging the oil seal and adjustment of the torque sensor as in the prior art. The torque sensor 10 can be attached easily and accurately without requiring skill for adjustment, etc., and the torque sensor 10 does not rattle and prevents abnormal noise from occurring in the past. can do.

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the case where the step D of the mounting device F is set to the same dimension as the stroke amount in the axial direction (thrust direction) of the rotor assembly with respect to the case 10c of the torque sensor 10 has been described. May be set to a stroke amount or more. Further, the stator assembly of the torque sensor 10 may be externally fitted to the output shaft 6 and the rotor assembly may be externally fitted to the input shaft.

  Further, the widths (dimensions) W1 and W2 in the circumferential direction of the first notch portion Fc and the second notch portion Fd are larger than the width w (see FIG. 2) in the circumferential direction of the main body 10a of the handle 10b of the torque sensor 10. It only has to be set.

2 ... Input shaft 6 ... Output shaft 7 ... Torsion bar 10 ... Torque sensor 10b ... Handle (contact portion)
10c ... Case 11 ... Power steering motor F ... Mounting device Fa ... Base Fb ... Cylindrical part Fc ... First notch Fd ... Second notch D ... Step

Claims (1)

A torque sensor that is provided in an electric power steering device that generates an auxiliary steering torque according to a steering torque applied to a steering wheel and transmits the auxiliary steering torque to an output shaft of a steering mechanism, and detects the operation torque. And a stator assembly housed in the case and arranged to be movable relative to the case and connected to a steering wheel or externally fitted to the output shaft, and different magnetic poles alternately in the circumferential direction. A rotor assembly having an annular magnet disposed on the output shaft or the input shaft and disposed inside the stator assembly so as to be movable in the axial direction relative to the stator assembly; The stator assembly for the rotor assembly housed in the case A magnetic sensor unit for detecting a magnetic flux based on a rotational difference of the yellowtail, and a torsion bar having both ends fixed to the input shaft and the output shaft, respectively, is twisted by a steering force applied to the steering wheel, whereby the input In a torque sensor mounting device for mounting a torque sensor that detects a rotation difference generated between a shaft and the output shaft as the steering torque by the magnetic sensor unit,
An annular base that is rotatably mounted on the outside of the output shaft via a bearing and in which the case is fitted;
A cylindrical portion integrally formed on one side of the base portion;
A first cutout part formed by cutting a part of the end face of the cylindrical part and abutting the contact part of the case when the case is pushed into the cylindrical part;
The case is formed in the part of the end surface of the cylindrical portion with a step projecting from the edge of the first notch portion to the opposite side of the pushing direction of the case, and the case is inserted into the cylindrical portion after the case is completed. A second notch portion for positioning in the axial direction by contacting the contact portion by rotating
The torque sensor mounting device, wherein the step is set according to a movement amount of the rotor assembly or the stator assembly with respect to the case of the torque sensor.

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