JP4010154B2 - Torque detection device and electric power steering device using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a torque detection device for detecting torque applied to a rotating body and an electric power steering device using the same.
[0002]
[Prior art]
As an electric power steering device for a vehicle, for example, a steering torque applied to the input shaft is detected by a relative angular displacement amount of an input shaft connected to a steered wheel and an output shaft connected coaxially to the input shaft via a torsion bar. A torque sensor; a controller that drives a steering assist motor based on the torque detected by the torque sensor; and a transmission means that transmits the rotational force of the motor to the steering mechanism. The operation of the steering mechanism according to the control is assisted by the rotation of the motor to reduce the labor burden on the driver for steering.
[0003]
As torque sensors of this electric power steering device, Japanese Utility Model Laid-Open No. 5-65750, Japanese Patent Application Laid-Open No. 2000-310573, Japanese Patent Application Laid-Open No. 8-122175, Japanese Patent Application Laid-Open No. 10-160600, Japanese Patent Application Laid-Open No. 10-339679. Non-contact sensors are known as described.
[0004]
The non-contact type sensor described in Japanese Utility Model Publication No. 5-65750 is provided with three magnetic rings arranged around an input shaft and an output shaft and having rectangular teeth on the end surface in the circumferential direction, and the magnetic Two coils arranged around the periphery of the ring for generating magnetic flux, and two connectors connected to each coil via two conductors, respectively, the magnetic ring corresponding to the torsion of the torsion bar When the relative rotation occurs, the facing area of the tooth portion changes, and the steering torque is detected by changing the impedance of the coil.
[0005]
The connector includes two terminals connected to two conductors and a housing that protects the connection of each terminal to the conductor.
The control unit is provided with a circuit board having four connection holes to which terminals of two connectors are connected by insertion.
[0006]
The connection to the control unit of the connector is such that the terminal of the connector is inserted into the two connection holes in a state where the housing of the first connector is picked by the fingertip, and further, the housing of the second connector is picked by the fingertip. In this state, the terminal of the connector is inserted into the remaining two connection holes, and the tip of each terminal is soldered.
[0007]
[Problems to be solved by the invention]
However, in the case of the conventional one having two coils, each of the two connectors connected to each coil via a conducting wire is a small size formed to be about half the thickness of the fingertip. Therefore, it is difficult to perform the work of picking up the housing of this small connector with a fingertip and inserting the terminal into the connection hole of the control unit, and connecting the two connectors by separate connection operations. There was a demand for an improvement in connection workability.
[0008]
The present invention has been made in view of such circumstances, and a main object thereof is to provide a torque detection device and an electric power steering device that can improve the connection workability of connectors connected to a plurality of coils. near Ru.
[0009]
[Means for Solving the Problems]
A torque detection device according to a first aspect of the present invention includes a detection unit that includes two coils disposed around an outer periphery of a rotating body to which torque is applied, and detects torque applied to the rotating body due to a change in impedance of each coil in the torque detector and a two connectors, one end of which is connected to the coils, each connector connecting portion of the terminal being connected via said wire to each coil, and the conductor of the terminal Each housing, and a housing portion for housing the housing and a connecting end side of the conducting wire to the terminal, two protrusions having different shapes, and a holding position of each connector in the housing portion A constraining concave portion for constraining the wiring position of the conductive wire at a position spaced apart from each other, and a retaining convex portion for preventing the conductive wire from being pulled out from the housing portion in a direction intersecting the longitudinal direction of the conductive wire. The connector housing has a holding body arranged side by side, one connector housing has a fitting hole into which one of the two protrusions is fitted, and the other connector housing has the other of the two protrusions fitted therein. It has the fitting hole which each has .
[0010]
An electric power steering device according to a second aspect of the present invention includes the torque detection device of the above-described invention and a circuit board provided with a connection hole connected to a terminal of the connector , and the torque detection device detects A control unit that drives a motor for assisting steering based on torque; a case member that has a groove in which the conducting wire is housed; and the control unit is built in; the groove and the connection hole of the case member; And a transmission means for transmitting the rotational force of the motor to the steering mechanism.
[0011]
In the first invention and the second invention, since a plurality of connectors connected to a plurality of coils can be held side by side in the holding body, in a state where one holding body larger than the connector is gripped, In addition, the terminals of each connector can be simply inserted and connected to the connection hole by a single connection operation, so that the assembly workability can be improved and the cost can be reduced. Moreover, since the housing of each connector is hold | maintained at the accommodating part of the holding body, each connector can be protected by the holding body.
[0014]
In the present invention, since the connector can be held by the holding body by fitting the fitting hole of the housing to the convex portion of the holding body, the connector can be easily held on the holding body.
[0016]
Further, in the present invention, since the wiring position of the conducting wire can be restrained by the restraining recess, the holding body can be picked up without being obstructed by the conducting wire, and the connection workability of the connector is further improved. In addition, it is possible to prevent the conductive wire from being attached between the holding body and another member facing the holding body.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.
1 is a cross-sectional view showing the configuration of the torque detection device, FIG. 2 is an enlarged view showing the configuration of the connector connecting portion, FIG. 3 is a perspective view showing the configuration of the connector and the holding body, and FIG. FIG. 5 is a front view of the state in which the holding body holds the connector, FIG. 6 shows the structure of the holding body, (a) is a front view, (b) is a plan view, and (c) is a plan view. (a) I-I sectional view, (d) is a sectional view taken along the line II-II in (a), and FIG. 7 is a sectional view showing a configuration of an electric power steering apparatus equipped with a torque detector. .
[0020]
The electric power steering apparatus has an upper end connected to a steering wheel A for steering, an input shaft 1 having a cylindrical portion 1a at the lower end, and a cylindrical portion of the input shaft 1 inserted into the cylindrical portion 1a. A torsion bar 2 that is coaxially connected to 1a and twisted by the action of a steering torque applied to the steered wheel A, an output shaft 3 whose lower end is coaxially connected to the lower end of the torsion bar 2, and the torsion bar 2 A torque detecting device B for detecting a steering torque applied to the steered wheel A based on a relative rotational displacement amount of the input shaft 1 and the output shaft 3 corresponding to the torsion of the motor, and for assisting steering based on the torque detected by the torque detecting device B The control unit 5 that drives and controls the motor 4, the speed reduction mechanism 6 that transmits the rotation of the motor 4 to the output shaft 3, and the speed reduction mechanism 6 and the torque detection device B are accommodated and the input shaft 1 And a tubular casing 7 rotatably supporting the fine output shaft 3. The input shaft 1 and the output shaft 3 constitute a rotating body.
[0021]
The output shaft 3 has an insertion hole 3a into which the lower end portion of the cylindrical portion 1a is inserted at the upper end, and the lower end portion of the cylindrical portion 1a is supported by the insertion hole 3a via a needle bearing 8. Has been. The intermediate portion of the output shaft 3 is supported in the cylindrical case 7 via a pair of ball bearings 9 and 10.
[0022]
The torque detector B includes first and second coils 11 and 12 that generate magnetic fluxes that are spaced apart from each other in the axial length direction on the outer periphery of the upper end portion of the output shaft 3 and the middle portion of the cylindrical portion 1a. A first magnetic ring 13 disposed inside the first coil 11 and fitted and fixed to the outer periphery of the upper end portion of the output shaft 3, and disposed inside the second coil 12 and in the middle of the cylindrical portion 1a. The second magnetic ring 14 and the third magnetic ring 15 that are fitted and fixed to the outer periphery of the part, and the first and second coils 11 and 12 are separately housed, and two coil housing rings made of a magnetic material. 16 and 17, an annular retainer 18 interposed between the coil housing rings 16 and 17, and the first and second coils 11 and 12 via two conductors 19, 19, 20 and 20, respectively. First and second connectors 21 and 22 connected to each other, and the connectors And a holding member 23 for holding side by side 1, 22, coil receiving ring 16, 17 each are fitted and held in the fitting inner surface 7a of the cylindrical casing 7.
[0023]
A plurality of rectangular teeth are circumferentially arranged at equal pitches on the opposing end faces of the first and second magnetic rings 13 and 14 and the opposing end face of the third magnetic ring 15 and the second magnetic ring 14. Is formed. The magnetic flux generated by the first coil 11 constitutes the first magnetic circuit by the coil housing ring 16, the first magnetic ring 13, and the second magnetic ring 14, and the magnetic flux generated by the second coil 12. Thus, the coil housing ring 17, the second magnetic ring 14, and the third magnetic ring 15 constitute a second magnetic circuit. For this reason, when a steering torque is applied to the steered wheel A and the torsion bar 2 is twisted, the facing area between the tooth portion of the first magnetic ring 13 and the tooth portion of the second magnetic ring 14 is changed. The impedance of one coil 11 changes, and the torque applied to the torsion bar 2 can be detected by the voltage output according to the change. At this time, the third magnetic ring 15 and the second magnetic ring 14 having tooth portions facing the non-tooth portion end face of the second magnetic ring 14 rotate relative to each other, and the impedance of the second coil 12 changes. The torque is corrected by the voltage output according to the change. That is, since the impedance of the first coil 11 varies depending on the ambient temperature of the first coil 11 in addition to the actual torque applied to the torsion bar 2, the impedance of the first coil 11 due to the ambient temperature is changed. The change is corrected, and a torque that is not affected by temperature can be detected.
[0024]
The first connector 21 includes two terminals 21 a and 21 a connected to the two conductors 19 and 19, and a housing 21 b that protects the connection of the terminals 21 a and 21 a to the conductors 19 and 19. The second connector 22 is provided with two terminals 22a connected to the two conductors 20, 20, and 22a, the terminal 22a, and a housing 22 b that protects the connection to wires 20, 20 22a. Each housing 21b, 22b has three insertion holes 21c, 22c that are formed to be spaced apart from each other, and the terminals 21a, 21a and 22a, 22a are inserted and fixed in the insertion holes 21c, 22c at both ends. . The central insertion holes 21c and 22c are fitting holes into which protrusions 23g described later are fitted.
[0025]
The holding body 23 has a rectangular bottom wall 23a, three standing walls 23b, 23c, 23d erected at both longitudinal ends and the center of the bottom wall 23a, and 2 between adjacent standing walls 23b, 23c and 23c, 23d. Two holding pieces 23h, 23i having protrusions 23g, which are erected from the bottom wall 23a in the two accommodating portions 23e, 23f and into which the central insertion holes 21c, 22c in the housings 21b, 22b are fitted, and the standing wall 23b, 23d, and a retaining projection 23h at the upper end of the bottom wall 23a projecting from one end in the width direction of the bottom wall 23a, and a pair of the upper end of the standing wall 23c projecting from the end of the bottom wall 23a in the width direction. Each of the retaining projections 23k, 23k, 23k and the bottom wall 23a, and constraining recesses 23m, 23n for restraining the wiring positions of the conductors 19, 20, respectively. Description unit 23e, the to 23f housing 21b, 22b are housed.
[0026]
The protrusions 23g of the holding piece 23h and the protrusions 23g of the holding piece 23i have different shapes, and the fitting of the housings 21b and 22b is incorrect, in other words , the insertion holes 21c and 22c at the center of the housings 21b and 22b. Is fitted to the holding pieces 23h, 23i, the housing 21b can be fitted to the holding pieces 23h in the state shown in FIG. 2, and the housing 22b is fitted to the holding pieces 23i in the state shown in FIG. The connectors 21 and 22 can be securely fitted to prevent errors in holding positions. Further, the protrusion 23g locks the housings 21b and 22b when the insertion holes 21c and 22c are fitted, so that the holding state of the housings 21b and 22b in the accommodating portions 23e and 23f can be maintained. It is.
[0027]
The retaining projections 23j are opposed to each other at a distance slightly smaller than the thickness of the conducting wires 19 and 20, and from between the retaining projections 23j to the constraining recesses 23m and 23m between the standing walls 23b and 23d and the holding pieces 23h and 23i. The inserted conductors 19 and 20 can be prevented from coming out. Further, the retaining protrusion 23k has a height such that the distance between the retaining pieces 23h and 23i is slightly smaller than the thickness of the conducting wires 19 and 20, and the retaining protrusion 23k and the retaining pieces 23h and 23i The lead wires 19 and 20 inserted into the constraining recesses 23n and 23n between the standing wall 23a and the holding pieces 23h and 23i can be prevented from coming out. Further, the lead wire insertion side of each retaining projection 23j, 23k is a tapered surface so that the lead wires 19, 20 can be inserted easily.
[0028]
The coil receiving rings 16 and 17 are connected to the cylindrical portions 16a and 17a in which the coils 11 and 12 are fitted, and radially inward from one end of the cylindrical portions 16a and 17a. It consists of flanges 16b, 17b facing the outer peripheral surface of one magnetic ring 13 or second magnetic ring 14. The coil receiving rings 16 and 17 are generally formed by cutting the entire surface, but in the embodiment, a metal plate having a thickness (including a dimensional tolerance) equal to the thickness of the flanges 16b and 17b is pressed. By molding and cutting only a part, the number of cutting processes is reduced and the processing cost is reduced.
[0029]
Cutting is required after press forming because a predetermined gap is secured between the inner peripheral surfaces 16c and 17c of the flange portions 16b and 17b and the first and second magnetic rings 13 and 14, and torque detection accuracy is achieved. This is to guarantee. Therefore, at least the outer peripheral surfaces of the cylindrical portions 16a and 17a and the inner peripheral surfaces 16c and 17c of the flange portions 16b and 17b are cut, and their dimensional tolerances are relatively small.
[0030]
By the way, when the outer peripheral surfaces of the cylindrical portions 16a and 17a are cut, burrs are generated at the end of this processing step. Therefore, in the embodiment, a continuous portion 16d between the cylindrical portions 16a and 17a and the flange portions 16b and 17b. , 17d from the middle to the other end of the cylindrical portions 16a, 17a.
[0031]
8 and 9 are enlarged cross-sectional views of a part of the coil housing ring. This cutting is performed so that the other ends of the cylindrical portions 16a and 17a are the cutting start ends, and the middle of the connecting portions 16d and 17d is the cutting end, and the connecting portions 16d and 17d have outer peripheral surfaces as shown in FIG. The taper surface (b portion) is smaller than (a portion). As a result, the burr generated at the end of cutting is radially inward from the outer peripheral surface (portion a).
[0032]
Further, when the inner peripheral surfaces 16c and 17c of the flange portions 16b and 17b are cut, burrs are generated at the end of this processing step, so that the end is cut to have a non-pointed shape. When the amount of cutting at the end is increased, the effective length H of the inner peripheral surface of the flange portions 16b and 17b cannot be secured. Therefore, in the embodiment, the thickness tolerance of the metal plate is considered and the minimum tolerance is taken into consideration. Cutting is performed so that the taper surface (c portion) is larger than the inner peripheral surface from a position slightly smaller than the position (see FIG. 9). As a result, even when the thickness tolerance of the metal plate is the smallest, burrs generated at the end of cutting are radially outward from the inner peripheral surfaces 16c and 17c.
[0033]
The cylindrical case 7 is provided with an insertion hole 7b facing the fitting inner surface 7a, and the conductive wires 19 and 20 are inserted into the insertion hole 7b.
[0034]
The control unit 5 uses a circuit board 5a and a microprocessor (not shown) mounted on the circuit board 5a, and connectors 21 and 22 of the torque detection device B are connected to the input unit of the control unit 5. A drive circuit of the motor 4 is connected to the output unit. The circuit board 5a is provided with a plurality of connection holes 5b into which the terminals 21a and 22a of the connectors 21 and 22 are inserted. The control unit 5 is built in the case member 24, and the case member 24 is detachably attached to a position near the insertion hole 7 b in the cylindrical case 7. The case member 24 is erected on both sides of the circuit board 5a, and includes two protective walls 24a and 24b that protect the connectors 21 and 22, a groove 24c that accommodates the conductors 19 and 20, a portion of the groove 24c, and A lid 24d that covers the connection hole 5b portion of the circuit board 5a. By removing the lid 24d, the terminals 21a and 22a of the connectors 21 and 22 can be inserted into the connection hole 5b. It has become.
[0035]
The speed reduction mechanism 6 meshes with the worm wheel 6a and the worm wheel 6a fixed by fitting at a position adjacent to the outer periphery of the output shaft 3 in the axial direction of the torque detection device B, and driving the motor 4 And a worm 6b connected to the shaft, the rotation of the drive shaft is decelerated and transmitted to the output shaft 3, and is transmitted from the output shaft 3 to, for example, a rack and pinion type steering mechanism (not shown) via a universal joint. It is like that. The output shaft 3 and the universal joint constitute transmission means for transmitting the rotational force of the worm wheel 6a to the steering mechanism.
[0036]
In the electric power steering apparatus configured as described above, the two connectors 21 and 22 of the torque detection apparatus B are connected to the control unit 5 as shown in FIG. In this case, as shown in FIG. 3 to FIG. 5 , the connectors 21 and 22 are previously placed in the accommodating portions 23 e and 23 f of one holding body 23 with one surface of the connector 21 and the other surface of the connector 22 in the same direction. Since they are held side by side, the terminals 21a and 22a of the connectors 21 and 22 can be inserted into the connection holes 5b by gripping the holding body 23. As a result, the connectors 21 and 22 can be easily connected to the control unit 5 with a single connection operation, so that the assembly workability can be improved and the cost can be reduced. Further, since the holding body 23 in which the connectors 21 and 22 are accommodated and held is picked without picking the connectors 21 and 22, a good connection state between the terminals 21a and 22a and the conductors 19 and 20 can be reliably maintained. . Moreover, since the connection side with each of the conductors 19 and 20 with the terminals 21a and 22a is restrained by the restraining recesses 23m and 23n of the holding body 23 by the retaining projections 23j and 23k, the conductors 19 and 20 are not obstructed. The holding body 23 can be picked, and the connection workability of the connectors 21 and 22 can be further improved. Further, it is possible to prevent the conducting wires 19 and 20 from being attached between the holding body 23 and the lid body 24d, for example.
[0037]
Further, in the embodiment described above, since the coil housing rings 16 and 17 are press-molded, the number of cutting steps of the coil housing rings 16 and 17 can be reduced, and the cylindrical portions 16a and 17a. The outer peripheral surface is cut so that the middle of the continuous portions 16d and 17d is the end of cutting, and the burr generated at the end of cutting is positioned radially inward from the outer peripheral surface. The coil receiving rings 16 and 17 can be fitted to the fitting inner surface 7a of the cylindrical case 7 without any problem. Further, since cutting is performed from the middle of the continuous portions 16d and 17d to the other ends of the cylindrical portions 16a and 17a, when the coil receiving rings 16 and 17 are fitted to the fitting inner surface 7a, the continuous portions 16d and 16d are connected. The cylindrical surface 16a, 17a can be inserted into the fitting inner surface 7a with the cutting surface of 17d in contact with the edge of the fitting inner surface 7a, and the cutting surface can be used as a guide surface. Workability can be improved.
[0038]
Further, the inner peripheral surfaces 16c and 17c of the flange portions 16b and 17b in the press-formed coil housing rings 16 and 17 are arranged so that the inner peripheral surfaces 16c and 17c are slightly smaller than the position of the minimum tolerance of the plate thickness dimension. Cutting is performed so that the taper surface has a dimension larger than that of 17c, and the burr generated at the end of cutting is positioned radially outward from the inner peripheral surfaces 16c and 17c. In addition, a predetermined gap can be secured between the inner peripheral surfaces of the flange portions 16b and 17b and the first and second magnetic rings 13 and 14, and torque detection accuracy can be ensured.
[0039]
In the above-described embodiment, the connectors 21 and 22 having the terminals 21a and 22a connected to the coils 11 and 12 via the conductors 19 and 20 are provided. Alternatively, the terminals 11a and 22a may be connected to both ends of the coils 11 and 12, respectively.
Further, the torque detection device according to the present invention may be used for devices other than the electric power steering device in addition to the electric power steering device.
[0040]
【The invention's effect】
According to the first and second inventions, the terminal of each connector can be simply inserted into the connection hole of the connected body in a state where one holding body larger than the connector is picked and the connection operation is performed once. As a result, the assembly workability can be improved and the cost can be reduced.
[0041]
Moreover, according to this invention, each connector can be protected by one holding body, and the favorable connection state of a conducting wire and a terminal can be maintained reliably.
[0042]
In addition, according to the present invention, the connector can be easily held on the holding body.
[0043]
Moreover, according to this invention, a holding body can be picked without being disturbed by a conducting wire, and the connection workability | operativity of a connector can be improved further.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of a torque detection device according to the present invention.
FIG. 2 is an enlarged view showing a configuration of a connector connecting portion of the torque detection device according to the present invention.
FIG. 3 is a perspective view showing configurations of a connector and a holding body of the torque detection device according to the present invention.
FIG. 4 is a perspective view of the torque detection device according to the present invention with one of the connectors removed.
FIG. 5 is a front view of a state in which the holding body of the torque detection device according to the present invention holds the connector.
6A and 6B show a configuration of a holding body of a torque detection device according to the present invention, in which FIG. 6A is a front view, FIG. 6B is a plan view, and FIG. 6C is a cross-sectional view taken along line I-I in FIG. (D) is a sectional view taken along line II-II in (a).
FIG. 7 is a cross-sectional view showing a configuration of an electric power steering apparatus including a torque detection device according to the present invention.
FIG. 8 is an enlarged cross-sectional view of a part of a coil housing ring of the torque detection device according to the present invention.
FIG. 9 is an enlarged cross-sectional view of a part of a coil housing ring of the torque detector according to the present invention.
[Explanation of symbols]
B Torque detection device 1 Input shaft (rotating body)
3 Output shaft (rotating body)
4 Motor 5 Control section 11, 12 Coil 13-15 Magnetic ring 16, 17 Coil receiving ring 16a, 17a Cylindrical section 16b, 17b Ridge section 16d, 17d Continuous section 19, 20 Conductor 21, 22 Connector 21a, 22a Terminal 21b, 22b Housing 21c, 22c Insertion hole (fitting hole)
23 Holding body 23e, 23f Housing part 23g Protrusion 23m, 23n Restraint recess

Claims (2)

Has two coils disposed around the outside of the rotating body torque is applied, a detector for detecting a torque applied to the rotating body by the change in the impedance of each coil, one end is connected to the coil In the torque detection device comprising two connectors,
Each of the connectors has a terminal that is connected to each coil via a conductor, and a housing that protects a connection portion of the terminal to the conductor,
Each of the housings, an accommodating portion for accommodating the connecting end side of the conducting wire to the terminal, two protrusions having different shapes, and wiring of the conducting wires at positions separated from the holding positions of the connectors in the accommodating portion A holding recess that holds the connectors side by side, and includes a restraining recess that restrains the position, and a retaining projection that prevents the lead from being pulled out from the housing portion in a direction that intersects the longitudinal direction of the lead. ,
One connector housing has a fitting hole into which one of the two protrusions is fitted, and the other connector housing has a fitting hole into which the other of the two protrusions is fitted. A torque detection device. A torque assisting device according to claim 1, and a circuit board provided with a connection hole connected to a terminal of the connector , and a steering assist motor based on the torque detected by the torque detecting device A control unit that drives the case, a case member that has a groove in which the conductive wire is housed, the control unit is built in, a lid that covers the groove and the connection hole of the case member, and the motor An electric power steering device comprising: a transmission means for transmitting a rotational force to the steering mechanism.

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