JP5949320B2 - Yoke assembly for torque detection device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a yoke assembly used in a torque detector for detecting rotational torque applied to a rotating shaft, and a method for manufacturing the same.

  As a torque detection device that detects a steering torque applied to a steering member such as a steering wheel, a first shaft and a first shaft that are coaxially connected by a torsion bar with a steering shaft (rotating shaft) that connects the steering member and the steering mechanism. A cylindrical magnet that is divided into two axes and rotates integrally with one of the first axis and the second axis, and one set of two that surrounds the outside of the cylindrical magnet and rotates integrally with the other of the first axis and the second axis Provided with a yoke ring, detecting a change in magnetic flux generated in the two yoke rings and detecting a relative angular displacement generated between the first shaft and the second shaft, thereby operating the steering shaft by operating the steering member. (For example, refer to Patent Documents 1 to 3).

  In addition, as a method of manufacturing a yoke assembly in which a set of two yoke rings is resin-molded, protrusions provided on both end surfaces in the axial direction of a spacer formed of a nonmagnetic material are fitted between adjacent magnetic pole claws of the yoke ring. By aligning, the yoke ring is resin-molded in a state of being positioned on the spacer (see Patent Document 2), and adjacent to the yoke ring having a positioning hole penetrating the position aligned with the magnetic pole claw in the axial direction. Using a yoke ring provided with a positioning hole penetrating the position aligned between the magnetic pole claws in the axial length direction, positioning the positioning holes of each set of two yoke rings through a common positioning pin provided in the mold In such a state, there is one in which a molding die is filled with a resin and molded (see Patent Document 3).

JP 2003-149062 A JP 2004-125627 A JP 2008-002979 A

  In the method of manufacturing a yoke assembly for a torque detection device in which a set of two yoke rings is positioned using a spacer as described in Patent Document 2, the manufacturing cost of the spacer for positioning the yoke ring increases and injection molding is performed. At this time, since it is necessary to set two yoke rings as a set to the spacer and further to set the spacer to the mold, there is a problem that it takes time.

On the other hand, in the method of manufacturing a yoke assembly for a torque detection device that positions a set of two yoke rings using positioning pins provided on a molding die as in Patent Document 3, the manufacturing method of Patent Document 2 is used. Since such a spacer is unnecessary, the above problem can be solved.
However, since the positioning of the two yoke rings is performed by a common positioning pin, the positioning pin is removed from the positioning hole of the yoke ring over the entire length in order to perform die cutting in the longitudinal direction (axial length direction) of the positioning pin. It is necessary to reduce the diameter.
Therefore, the rigidity and strength of the positioning pin are not sufficient, the elongated positioning pin may be deformed by the pressure of the injection molding, and the positioning accuracy of the yoke ring may be lowered, or the yoke ring is gripped by the robot. Since there is a case where the elongated positioning pin is broken when the positioning pin provided in the mold is inserted into the positioning hole of the yoke ring, there is room for improvement.

  Therefore, in view of the above-described situation, the present invention intends to solve the problem that the yoke for positioning the yoke ring can be eliminated, but the yoke in the mold is not provided with a positioning pin in the mold. The object of the present invention is to provide a yoke assembly for a torque detection device capable of accurately and reliably positioning a ring and a method for manufacturing the same.

In order to solve the above-described problem, a yoke assembly for a torque detection device according to the present invention is a cylinder in which a plurality of magnetic poles are arranged in parallel on the outer periphery, fixed to one of a first shaft and a second shaft connected coaxially. In order to detect a change in magnetic flux generated in response to a relative angular displacement caused by a rotational torque applied to the first axis and the second axis within a magnetic field formed by the magnet, the magnet is fixed to the other of the first axis and the second axis. A torque detecting device that is integrally held by a resin-made holding cylinder in a state in which a pair of two yoke rings are positioned so that a plurality of magnetic pole claws equally arranged on the inner peripheral side are alternately arranged A yoke assembly for a vehicle, wherein the set of yoke rings is formed with a circumferential positioning portion formed of a concave portion and a convex portion on an outer peripheral edge of the annular portion. axial direction front and rear surfaces of the convex portion to be visually recognized And features.

  In addition, the method of manufacturing a yoke assembly for a torque detection device according to the present invention provides a plurality of magnetic poles on the outer periphery fixed to one of the first shaft and the second shaft connected coaxially in order to solve the above problem. In order to detect a change in magnetic flux caused by a relative angular displacement caused by a rotational torque applied to the first axis and the second axis in a magnetic field formed by cylindrical magnets arranged side by side, the first axis and the second axis A pair of yoke rings fixed to the other of the two are integrally held by a resin holding cylinder in a state where a plurality of magnetic pole claws arranged equally on the inner peripheral side are alternately arranged. A method of manufacturing a yoke assembly for a torque detection device, wherein the set of yoke rings includes a circumferential positioning portion including a concave portion and a convex portion formed on an outer peripheral edge of the annular portion. Yes, the circumferential positioning part of the yoke ring is fitted A state that the positioning with a mold, characterized in that molded by filling a resin into the mold containing the mold.

  As described above, according to the yoke assembly for a torque detection device and the method for manufacturing the same according to the present invention, the positioning of two yoke rings is set in the circumferential direction formed on the outer peripheral edge of the annular portion of the yoke ring. Since it is a configuration that is performed by fitting the part to the mold, as in the configuration in which the yoke ring is positioned by the spacer, the manufacturing cost is not increased, and the setting at the time of injection molding does not take time, Like the configuration in which the yoke ring is positioned using the positioning pin provided on the molding die, the elongated positioning pin is deformed by the pressure of the injection molding and the positioning accuracy of the yoke ring is lowered, or the yoke ring is Elongated positioning pins do not break when set in the mold, and the yoke ring can be positioned accurately and reliably in the mold. It exhibits the remarkable effect that.

1 shows a yoke assembly for a torque detection device according to an embodiment of the present invention, where (a) is a perspective view and (b) is a longitudinal sectional view. A set of two yoke rings is shown, (a) is a perspective view of one yoke ring, and (b) is a perspective view of the other yoke ring. A set of two yoke rings is shown, (a) is a plan view of one yoke ring, and (b) is a plan view of the other yoke ring. It is a perspective view which shows typically positioning of the yoke ring in a shaping | molding die. It is a perspective view which shows the fitting part formed in the lower mold | type in order to position a yoke ring, and description of the center core is abbreviate | omitted.

Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments shown in the accompanying drawings, and includes all the embodiments that satisfy the requirements described in the claims. It is a waste.
The yoke assembly for a torque detection device according to the present invention is used in a torque detection device that detects rotational torque by detecting a relative angular displacement that occurs between a first shaft and a second shaft that are coaxially connected, In a magnetic field formed by a cylindrical magnet fixed to one of the first axis and the second axis and having a plurality of magnetic poles arranged on the outer circumference, relative angular displacement is caused by rotational torque applied to the first axis and the second axis. In order to detect the change of the magnetic flux which arises according to this, it fixes to the other of the said 1st axis | shaft and the 2nd axis | shaft.

  As shown in the perspective view of FIG. 1 (a) and the longitudinal sectional view of FIG. 1 (b), the torque detecting device yoke assembly 1 according to the embodiment of the present invention comprises two sets of yoke rings 2, 3 are positioned so that the plurality of magnetic pole claws 6, 6,... Equally arranged on the inner peripheral side thereof are alternately arranged, are held together by the resin holding cylinder 4, and the shaft of the holding cylinder 4 is It is fixed to the other of the first shaft and the second shaft by using a metal collar 5 fitted on the inner peripheral side of one side portion (the portion without the yoke rings 2 and 3) in the longitudinal direction.

As shown in the perspective view of FIG. 2 and the plan view of FIG. 3, the yoke rings 2, 3 have circumferential positioning portions A including the concave portions 7 and the convex portions 8 on the outer peripheral edges of the annular portions 2 </ b> A, 3 </ b> A. In the yoke assembly 1 for a torque detector shown in FIG. 1 after the yoke rings 2 and 3 are insert-molded, the projections 8, 8,. axial direction front and rear surfaces 8A, 8A, ... and 8B, 8B, ... is visible.

  In addition, the circumferential positioning portion A composed of the concave portion 7 and the convex portion 8 has a concave and convex shape that repeatedly protrudes the convex portions 8, 8,... As shown in FIGS. Although it is preferable from the viewpoint of ease of fitting into the mold, as will be described later, it is also positioned in the circumferential direction with the mold (lower mold L and intermediate molds M1 and M2) positioned in the axial direction. It is sufficient if there is at least one concavo-convex part (for example, one having only one convex part 8 formed on the outer peripheral edge of the annular parts 2A, 3A). The shape and size are set so as not to affect the detection. Further, the repeated uneven shape may be other shapes such as a smooth waveform.

Next, a manufacturing method of the torque detection device yoke assembly 1 will be described.
The mold for the resin holding cylinder 4 shown in FIG. 1 includes a lower mold and an upper mold that can be separated in the axial length direction of the holding cylinder 4 and a pair of intermediate molds that can be separated in the radial direction therebetween. Composed in combination.
As shown in the perspective view of FIG. 4, the lower mold L includes a cylindrical center core 13 that stands vertically at the center of the upper surface, and the center core 13 is approximately equal to the inner diameter of the holding cylinder 4 to be molded. A fitting step 14 for fitting the collar 5 is provided around the tip of the core 13 having the same outer diameter.
Further, as shown in the perspective view of FIG. 4 and the perspective view of FIG. 5 in which the description of the core 13 is omitted, the yoke ring 2 is externally fitted to the core 13 on the upper surface of the lower mold L. A fitting portion B into which the circumferential positioning portion A of the yoke ring 2 is fitted is formed.
That is, in a state where the yoke ring 2 is fitted into the center core 13 of the lower mold L with the projecting side of the magnetic pole claws 6, 6,. Are fitted into the recesses 9, 9,... And the lower surfaces 8A, 8A,... Of the projections 8, 8,. On the other hand, it is positioned in the axial direction and positioned in the circumferential direction.

The intermediate molds M1 and M2 are semicircular split molds having hole molds 15 and 15 corresponding to the outer diameter of the holding cylinder 4 in the center and configured to be separable in the radial direction. A fitting portion B into which the three circumferential positioning portions A are fitted is formed.
That is, as described above, the yoke ring 2 is set on the lower mold L, moved to the upper surface of the lower mold L so that the intermediate molds M1, M2 are aligned, and the protruding side of the magnetic pole claws 6, 6,. In the state where the facing yoke ring 3 is fitted into the center core 13 of the lower die L, the convex portions 8, 8,... Of the yoke ring 3 are fitted into the concave portions 10, 10,. The lower surfaces 8B, 8B, ... of the parts 8, 8, ... are abutted against the contact surfaces 12, 12, ..., so that the yoke ring 3 is positioned in the axial direction with respect to the intermediate molds M1, M2 and It is also positioned in the direction.
In this state, the yoke rings 2 and 3 are positioned so that a plurality of magnetic pole claws 6, 6,... Equally arranged on the inner peripheral side are alternately arranged.

After positioning the yoke rings 2 and 3 as described above, the fixing collar 5 shown in FIG. 1 is fitted into the fitting step 14 provided at the tip of the center core 13 to position the intermediate rings M1 and M2. An upper mold (not shown) is set above the upper mold, and the upper mold and the lower mold L and the intermediate molds M1 and M2 are clamped so that the intermediate molds M1 and M2 are held between the upper mold and the lower mold L. The yoke assembly 1 is injection-molded by filling the cavity formed by the molten resin.
The yoke assembly 1 shown in FIG. 1 that has been injection-molded in this way needs to be lifted upward and formed into a shape that can be taken out from the lower mold L. Therefore, the lower surface of the convex portions 8, 8,. 8A, 8A, abutting-stop surfaces 11, 11 of the lower die L to stop against a ..., molten resin is included as a mold shape which do not fall ... on the lower side of the.

According to the manufacturing method of the yoke assembly 1 for a torque detection device as described above, the positioning of the two yoke rings 2 and 3 is formed on the outer peripheral edges of the annular portions 2A and 3A of the yoke rings 2 and 3. Since the circumferential positioning portions A and A are configured to be fitted to the lower mold L and the intermediate molds M1 and M2, the manufacturing cost is increased as in the configuration in which the yoke ring is positioned by the spacer, There is no need for labor in the set during injection molding, and the positioning of the yoke ring is performed by using the positioning pin provided on the mold, so that the elongated positioning pin is deformed by the pressure of the injection molding and the yoke ring is Positioning of the yoke ring in the mold is prevented without lowering the positioning accuracy or breaking the elongated positioning pin when the yoke ring is set on the mold by the robot. It can be carried out accurately and reliably.
In addition, as shown in FIGS. 2 and 3, two yoke rings 2, 3 having the same shape including the circumferential positioning portions A, A formed on the outer peripheral edges of the annular portions 2A, 3A are formed. Therefore, manufacturing costs can be reduced and parts management can be facilitated.

A Circumferential positioning part B Fitting part L Lower mold M1, M2 Intermediate mold 1 Yoke assembly 2, 3 York ring 2A, 3A Ring part 4 Holding cylinder 5 Collar 6 Magnetic pole claw 7 Recess 8 Protrusion 8A, 8B Axle length Front or rear direction 9, 10 Recess 11, 12 Stopping surface 13 Core 14 Stepped portion 15 for fitting Hole type

Claims (2)

Rotational torque applied to the first shaft and the second shaft in a magnetic field formed by a cylindrical magnet fixed on one of the first shaft and the second shaft connected on the same axis and having a plurality of magnetic poles arranged in parallel on the outer periphery. In order to detect a change in magnetic flux generated according to the relative angular displacement caused by the two, a set of two yoke rings fixed to the other of the first shaft and the second shaft are equally arranged on the inner peripheral side of each. A torque detecting device yoke assembly, which is integrally held by a resin-made holding cylinder in a state where a plurality of magnetic pole claws are alternately arranged.
The set of yoke rings is formed with a circumferential positioning portion including a concave portion and a convex portion on the outer peripheral edge of the annular portion,
A yoke assembly for a torque detector, wherein the front surface and the rear surface of the convex portion of the set of yoke rings in the axial length direction are visually recognized.
Rotational torque applied to the first shaft and the second shaft in a magnetic field formed by a cylindrical magnet fixed on one of the first shaft and the second shaft connected on the same axis and having a plurality of magnetic poles arranged in parallel on the outer periphery. In order to detect a change in magnetic flux generated according to the relative angular displacement caused by the two, a set of two yoke rings fixed to the other of the first shaft and the second shaft are equally arranged on the inner peripheral side of each. A method of manufacturing a yoke assembly for a torque detector, which is integrally held by a resin-made holding cylinder in a state where a plurality of magnetic pole claws are alternately arranged.
The set of yoke rings is formed with a circumferential positioning portion including a concave portion and a convex portion on the outer peripheral edge of the annular portion,
A yoke assembly for a torque detector, wherein the yoke ring is molded by filling the molding die including the die with the positioning state using a die with which the circumferential positioning portion of the yoke ring is fitted. Solid manufacturing method.

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