JP2009006589A - Resin mold shaft material, its manufacturing method and torque detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin mold shaft material which can inhibit the damage, of a resin molding, caused by a change in the temperature such as atmospheric temperature. <P>SOLUTION: The resin mold shaft material has a shaft body 1 whose outer peripheral surface is covered with the resin molding 7, and also, an anti-slip fabricated part 2 for restricting the slippage of the resin molding 7 to the shaft body 1 and a smooth finish part 4 not fabricated for anti-slip, are alternately formed circumferentially to the outer peripheral face of the shaft body 1. Besides, the smooth finish part 4 is arranged in a peripheral position corresponding to the weld part 5 of the resin molding 7. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a resin mold shaft material. More specifically, the present invention relates to a resin mold shaft material that can be used as a rotor for a torque detection device, a manufacturing method thereof, and a torque detection device that can detect torque, such as an electric power steering device. It is.

  Conventionally, the resin mold shaft material in which the outer peripheral surface of the shaft body is covered with a resin molded body is used in various fields such as a rotor of a servo motor. As a resin mold shaft material used as a rotor of the servo motor, for example, a rotor whose shaft body is covered with a bonded magnet that is a resin molded body can be cited (for example, see Patent Document 1).

In the resin-molded shaft material described in Patent Document 1, a shaft body in which a rotlet process is performed on the entire circumferential surface and a minute concave surface is provided is covered with a bond magnet that is a resin molded body. Therefore, in such a resin mold shaft material, the shaft body and the bond magnet are strongly fastened.
Japanese Patent Laying-Open No. 2005-237047 (see FIG. 3)

  However, the resin mold shaft described in Patent Document 1 may cause a linear expansion coefficient difference between the shaft main body and the resin molded body due to a change in temperature such as air temperature, and the resin molded body may be damaged. There is a drawback of being.

  This invention is made | formed in view of the fault of the said prior art, and makes it one subject to provide the resin mold shaft material which can suppress the failure | damage of the resin molding which generate | occur | produces by temperature changes, such as temperature. .

  In addition, the present invention can provide the resin mold shaft material obtained with durability against damage to the resin molded product due to a difference in linear expansion coefficient between the shaft main body and the resin molded product caused by a change in temperature. It is another object to provide a method for producing a resin mold shaft material.

  Furthermore, another object of the present invention is to provide a torque detection device that exhibits high durability even when there is a change in temperature such as air temperature.

In one aspect, the present invention is a resin mold shaft material in which an outer peripheral surface of a shaft body is covered with a resin molded body,
Non-slip processing portions for preventing slip of the resin molded body with respect to the shaft main body and smooth portions not performing the anti-slip are alternately formed in the circumferential direction with respect to the outer peripheral surface of the shaft main body, The said smooth part is arrange | positioned in the circumferential direction position corresponding to the weld part of the said resin molding, It is related with the resin mold shaft material characterized by the above-mentioned.

  In the resin mold shaft according to the present invention, the anti-slip portion and the smooth portion are alternately formed in a circumferential direction with respect to the outer peripheral surface of the shaft main body, and the smooth portion is a weld of the resin molded body. The linear expansion coefficient between the shaft main body and the resin molded body is caused by a change in temperature without causing stress concentration in the weld portion of the resin molded body because the resin molded body is disposed at a circumferential position corresponding to the portion. Occurrence of breakage of the resin molded body due to the difference is suppressed.

  In the resin mold shaft according to the present invention, it is preferable that the anti-slip portion is formed by knurling or indentation. In the resin mold shaft of the present invention, when the anti-slip portion is formed by knurling or indentation, the fastening force between the shaft body and the resin molded body in the resin mold shaft can be further increased. .

  In the resin mold shaft of the present invention, examples of the resin molded body include those made of bond magnets having S poles and N poles alternately in the circumferential direction. Such resin-molded shaft material does not cause stress concentration in the welded portion of the bonded magnet, and the bond magnet breakage due to the difference in linear expansion coefficient between the shaft main body and the bonded magnet caused by temperature change is suppressed. The Further, such a resin mold shaft does not have to take into account damage due to stress concentration on the weld portion, the magnet can be thinned, and the torque detector can be reduced in size at low cost. Such a resin mold shaft material is suitable as a rotor of a torque detection device.

In another aspect of the present invention, the following steps (1) to (3):
(1) An anti-slip portion for preventing the resin molded body from slipping with respect to the shaft main body and a smooth portion not performing the anti-slip are alternately arranged in a circumferential direction with respect to the outer peripheral surface of the shaft main body. Forming step,
(2) A mold having gates at a plurality of positions in the circumferential direction is obtained in the step (1) so that an intermediate position between adjacent gates in the circumferential direction comes to a circumferential position corresponding to the smooth portion. A step of setting on the outer peripheral side of the shaft body; and (3) filling the inside of the mold with a resin molding material simultaneously and at the same speed from each gate of the mold set in the step (2). By this, it is related with the manufacturing method of the resin mold shaft material which covers the outer peripheral surface of a shaft main body with a resin molding including the process of covering the outer peripheral surface of the said shaft main body with the said resin molding.

  According to the resin mold shaft manufacturing method of the present invention, in manufacturing, a mold having gates at a plurality of positions in the circumferential direction, and a circumferential direction in which an intermediate position between adjacent gates in the circumferential direction corresponds to the smooth portion. In order to set the shaft body on the outer peripheral side so as to come to the position, in the obtained resin mold shaft material, no stress concentration occurs in the weld portion formed when filling the resin molding material, and due to temperature change Generation | occurrence | production of the failure | damage of the resin molding by the linear expansion coefficient difference between the shaft main body and resin molding which generate | occur | produces is suppressed. Therefore, according to the method for producing a resin mold shaft material of the present invention, the resin mold shaft material obtained is damaged by a difference in linear expansion coefficient between the shaft main body and the resin molded product caused by a change in temperature. It is possible to impart durability against the above.

According to another aspect of the present invention, a first shaft and a second shaft connected coaxially, a bond magnet formed on an outer peripheral surface of the first shaft, and a magnetic circuit in the magnetic field of the bond magnet A torque detection device comprising a plurality of soft magnetic bodies attached to the second shaft and a detector for detecting magnetic flux generated by the soft magnetic bodies,
Anti-slip processed portions for preventing the bonded magnet from slipping with respect to the first shaft and smooth portions not performing the anti-slip are alternately formed in the circumferential direction with respect to the outer peripheral surface of the first shaft. The torque detecting device is characterized in that the smoothing portion is disposed at a circumferential position corresponding to a weld portion of the bonded magnet.

  In the torque detection device of the present invention, the anti-slip processing portion and the smooth portion are alternately formed in a circumferential direction with respect to the outer peripheral surface of the first shaft, and the smooth portion is a weld portion of the bond magnet. Therefore, even if there is a change in temperature such as air temperature, breakage of the bonded magnet is suppressed, so that high durability is exhibited and it can be used for a long period of time.

  As described above, since the smooth portion of the resin mold shaft material of the present invention is arranged at a circumferential position corresponding to the weld portion of the resin molded body, stress concentration does not occur in the weld portion, There is an excellent effect that damage to the resin molded body due to a difference in linear expansion coefficient between the shaft main body and the resin molded body caused by a change in temperature is suppressed.

  Further, in the method of manufacturing a resin mold shaft according to the present invention, in manufacturing, a mold having gates at a plurality of positions in the circumferential direction is used, and a circumferential direction in which an intermediate position between adjacent gates in the circumferential direction corresponds to the smooth portion. According to the method for manufacturing a resin mold shaft material of the present invention, the weld formed when the resin mold shaft material is filled with the resin molding material is set to the outer peripheral side of the shaft main body so as to come to the position. Stress concentration does not occur in the portion, and the occurrence of breakage of the resin molded body due to the difference in linear expansion coefficient between the shaft main body and the resin molded body caused by temperature change is suppressed. Therefore, according to the method for producing a resin mold shaft material of the present invention, the resin mold shaft material obtained is damaged by a difference in linear expansion coefficient between the shaft main body and the resin molded product caused by a change in temperature. It is possible to impart durability against the above. In addition, the resin mold shaft manufacturing method of the present invention does not need to take into account damage due to stress concentration on the weld, etc., can reduce the thickness of the magnet, and can reduce the size of the torque detector at low cost.

  Since the torque detection device of the present invention includes the rotor that is the resin mold shaft material, even if there is a change in temperature such as air temperature, damage to the bond magnet is suppressed, and high durability is achieved. There is an excellent effect that it can be used over a period of time.

In one aspect, the present invention is a resin mold shaft material in which an outer peripheral surface of a shaft body is covered with a resin molded body,
Non-slip processing portions for preventing slip of the resin molded body with respect to the shaft main body and smooth portions not performing the anti-slip are alternately formed in the circumferential direction with respect to the outer peripheral surface of the shaft main body, The said smooth part is arrange | positioned in the circumferential direction position corresponding to the weld part of the said resin molding, It is related with the resin mold shaft material characterized by the above-mentioned.

  In the present specification, the “resin molded body” refers to one obtained by molding a resin molding material, and examples thereof include a cured resin and a bonded magnet.

  Although it does not specifically limit as said resin molding material, For example, resin, such as a thermosetting resin and a thermoplastic resin; Bond magnet molding material etc. are mentioned. Examples of the bonded magnet molding material include a material containing a magnetic powder and a binding material, and the magnetic powder is in a state of being bound by a binding material. The magnetic powder is not particularly limited, and examples thereof include rare earth magnets. The binding material is not particularly limited, and examples thereof include a thermosetting resin and a thermoplastic resin. Moreover, as said thermosetting resin, an epoxy resin, a phenol resin, etc. are mentioned, for example. Examples of the thermoplastic resin include styrene resin, urethane resin, polyester resin, polyamide resin polyphenylene sulfide resin (PPS), and the like.

  Hereinafter, embodiments of the resin mold shaft material of the present invention will be described with reference to the accompanying drawings. 1 and 2 are schematic explanatory views showing an embodiment of a rotor which is an example of a resin mold shaft material of the present invention. FIG. 1A and FIG. 2A are local projection views from above in the axial direction of the resin mold shaft with the mold 3 kept fitted. The state where the pipe 9 is not connected is shown. FIGS. 1B and 2B are side projection views of the resin mold shaft material of the present invention corresponding to FIGS. 1A and 2A, respectively.

  As shown in FIGS. 1 (b) and 2 (b), the resin mold shaft material of the present invention includes a non-slip processing portion 2 for preventing the resin molded body 7 from slipping against the shaft body 1, and the anti-slip portion thereof. The smooth portions 4 that do not perform are alternately formed in the circumferential direction with respect to the outer peripheral surface of the shaft body 1, and the smooth portions 4 are arranged at circumferential positions corresponding to the weld portions 5 of the resin molded body 7. There is one major feature.

  Therefore, in the resin mold shaft material of the present invention, the anti-slip processed portion 2 prevents the resin molded body 7 from slipping with respect to the shaft body 1, and the smooth portion 4 corresponds to the weld portion 5 of the resin molded body 7. Due to the arrangement in the directional position, an excellent effect is obtained in that the occurrence of stress concentration on the weld portion 5 of the resin molded body 7 is suppressed.

  The anti-slip processing part 2 is a part for preventing the resin molded body 7 from slipping on the shaft body 1. Thereby, the fastening force between the resin molding 7 and the shaft body 1 is increased. Moreover, the smooth part 4 is a part which does not carry out slip prevention.

  As the anti-slip processing part 2, a knurling part formed by knurling as shown in FIG. 1B, a dent processing part formed by denting as shown in FIG. Is mentioned. In the resin mold shaft of the present invention, when the anti-slip portion 2 is formed by knurling or indentation, the fastening force between the shaft body 1 and the resin molded body 7 in the resin mold shaft is further increased. This is advantageous in that

  Although it does not specifically limit as said knurling process, For example, the flat grain process prescribed | regulated to JIS B 0951, an eyelet process, etc. are mentioned. The knurled dimension in the knurled portion may be in a range in which the fastening force between the resin molded body 7 and the shaft body 1 is sufficiently exhibited.

  When the non-slip processing portion 2 is formed by recessing, the anti-slip processing portion 2 is formed by processing and arranging a plurality of recesses on the outer peripheral surface of the shaft body 1. The size and number of the recesses may be in a range that sufficiently exhibits the fastening force between the resin molded body 7 and the shaft body 1. In addition, when the anti-slip | skid process part 2 is a hollow process part, the smooth part 4 becomes a part by which the hollow is not arrange | positioned at the axial direction position.

  The weld portion 5 is usually formed by the gates 6 and 6 adjacent to each other in the circumferential direction when the resin molding material is filled in the mold 3 simultaneously and at the same speed from the plurality of gates 6 of the mold 3 during manufacture. It is formed in the middle position between. Further, in the resin mold shaft material of the present invention, there are as many welds 5 as the number of gates 6 of the mold 3 used in manufacturing the resin mold shaft material.

  In the conventional resin mold shaft material, like the conventional rotor shown in FIG. 3B, a resin molded body 7 (in this case, a bond magnet) is integrally formed around the shaft body 1, and the S pole and the N pole are formed. The poles are alternately arranged in the circumferential direction, and the non-slip processed portion 2 is formed on the outer peripheral surface of the shaft body 1. Therefore, in such a conventional resin mold shaft material, stress concentration occurs in the weld portion 5, thereby generating a crack in the weld portion 5 and causing damage to the resin molded body 7 (in this case, a bonded magnet).

  However, in the resin mold shaft material of the present invention, the smooth portion 4 is disposed at a circumferential position corresponding to the weld portion 5 of the resin molded body 7 as shown in FIGS. 1 (b) and 2 (b). Therefore, stress concentration does not occur in the weld portion 5, and the occurrence of damage to the resin molded body 7 due to a difference in linear expansion coefficient between the shaft main body 1 and the resin molded body 7 caused by temperature change is suppressed. can do.

  In the resin mold shaft of the present invention, the thickness in the radial direction of the resin molded body 7 covering the outer peripheral surface of the shaft body 1 can be appropriately set according to the use of the resin mold shaft. For example, when the resin molded body 7 is a bonded magnet, the thickness in the radial direction of the resin molded body 7 can be set as appropriate according to the use and size of the rotor.

  Examples of the resin molded body 7 include those made of bonded magnets having S poles and N poles alternately in the circumferential direction. The resin-molded shaft member made of a bond magnet in which the resin molded body 7 has S-poles and N-poles alternately in the circumferential direction does not cause stress concentration in the weld portion of the bond magnet, and the shaft is generated by a change in temperature. This is advantageous in that breakage of the bond magnet due to a difference in linear expansion coefficient between the main body and the bond magnet is suppressed. Such a resin mold shaft material is suitable as a rotor of a torque detection device. The resin mold shaft material is a resin mold shaft material in which the outer peripheral surface of the shaft main body 1 is covered with a bond magnet (resin molded body 7 in FIG. 1). The smooth portions 4 are alternately formed in the circumferential direction with respect to the outer peripheral surface of the shaft body 1, and the smooth portions 4 are arranged at circumferential positions corresponding to the weld portions 5 of the bonded magnet (resin molded body 7 in FIG. 1). The bonded magnet (resin molded body 7 in FIG. 1) is configured to have S poles and N poles alternately in the circumferential direction. In the resin mold shaft material, since the smooth portion 4 is disposed at a circumferential position corresponding to the weld portion 5 of the bonded magnet (for example, the resin molded body 7 in FIG. 1), the stress concentration is applied to the weld portion 5. Is not generated, and a bond magnet (for example, resin molded body 7 in FIG. 1) due to a difference in linear expansion coefficient between the shaft main body 1 and the bond magnet (for example, resin molded body 7 in FIG. 1) caused by a change in temperature. ) Is suppressed. Therefore, according to the said resin mold shaft material, even if there exists a change of temperature, such as temperature, the torque detection apparatus which exhibits high durability and can be used over a long period of time can be provided. Moreover, according to the said resin mold shaft material, it is not necessary to consider the damage by the stress concentration to a weld part, etc., a magnet can be made thin and a torque detection apparatus can be reduced in size inexpensively.

In another aspect of the present invention, the following steps (1) to (3):
(1) An anti-slip portion for preventing the resin molded body from slipping with respect to the shaft main body and a smooth portion not performing the anti-slip are alternately arranged in a circumferential direction with respect to the outer peripheral surface of the shaft main body. (2) In the step (1), a mold having gates at a plurality of positions in the circumferential direction is positioned in the circumferential direction corresponding to the smoothing portion so that an intermediate position between the gates adjacent to each other in the circumferential direction is located. A step of setting on the outer peripheral side of the obtained shaft main body; and (3) a resin molding material is ejected simultaneously and at the same speed from the gates of the mold set in the step (2), and the material in the mold The resin mold shaft material manufacturing method of covering the outer peripheral surface of the shaft body with the resin molded body, including the step of covering the outer peripheral surface of the shaft body with the resin molded body by filling with

  In the manufacturing method of the resin mold shaft material of the present invention, in manufacturing, a mold having gates at a plurality of positions in the circumferential direction is set so that an intermediate position between the gates adjacent to each other in the circumferential direction is a circumferential position corresponding to the smooth portion. There is one big feature in that it is set on the outer peripheral side of the shaft body so as to come. Therefore, according to the resin mold shaft manufacturing method of the present invention, when the resin molding material is filled, stress concentration occurs in the weld portion formed at an intermediate position between the adjacent gates in the circumferential direction of the mold. It does not occur, and damage to the resin molded body due to a difference in linear expansion coefficient between the shaft main body and the resin molded body caused by a change in temperature is suppressed. Therefore, the resin mold shaft manufacturing method of the present invention has a durability against the resin molded body breakage due to a difference in linear expansion coefficient between the shaft main body and the resin molded body caused by temperature change in the obtained resin mold shaft material. Sex can be imparted. Further, according to the method of manufacturing the resin mold shaft material, it is not necessary to consider damage due to stress concentration on the weld portion, and the magnet can be made thin, so that the torque detection device can be reduced in size at low cost.

  Hereinafter, an embodiment of a method for producing a resin mold shaft material of the present invention will be described with reference to the accompanying drawings. FIG. 1A and FIG. 2A are local projection views from above in the axial direction of the resin mold shaft in a state where the mold 3 is fitted, as described above. A state where no pipe is connected to the gate 6 is shown. FIG. 4 is a schematic explanatory view showing one embodiment of the method for producing the resin mold shaft material of the present invention. 4A is a cross-sectional view of the mold 3 in a state in which the mold 3 is fitted to the shaft body 1, and FIG. 4B is an external view of the mold 3 corresponding to FIG. 4A. FIG.

  In the resin mold shaft manufacturing method of the present invention, the non-slip processed portion 2 for preventing the resin molded body 7 from slipping against the shaft body 1 and the smooth portion 4 that does not prevent the slip are provided on the shaft body 1. It forms alternately with respect to an outer peripheral surface in the circumferential direction [process (1)].

  In the step (1), for example, the formation of the non-slip processed portion 2 and the smooth portion 4 on the outer peripheral surface of the shaft body 1 is performed by forming the unprocessed shaft, the portion for forming the anti-slip processed portion 2 and the smooth portion 4. For example, it may be carried out by strongly pressing against the pieces provided alternately with the parts for plastic deformation. The interval between the portion for forming the anti-slip processing portion 2 and the portion for forming the smooth portion 4 in the piece is appropriately determined according to the length of the outer periphery of the unprocessed shaft and the arrangement interval of the gate 6 of the mold 3 to be used. Can be set.

  Next, in the step (1), the mold 3 having the gates 6 at a plurality of positions in the circumferential direction is positioned so that the intermediate position between the gates 6 and 6 adjacent to each other in the circumferential direction is at the circumferential position corresponding to the smoothing portion 4. ) Is set on the outer peripheral side of the shaft body 1 obtained in [Step (2)]. In the step (2), as shown in FIG. 1 (a) and FIG. 2 (a), an anti-slip machined portion 2 and a smooth portion 4 are alternately formed in the circumferential direction with respect to the outer peripheral surface. A mold 3 having gates 6 at a plurality of positions in the circumferential direction is set on the main body 1 such that an intermediate position between the gates 6 and 6 adjacent to each other in the circumferential direction comes to a circumferential position corresponding to the smoothing portion 4.

  As shown in FIG. 4B, the mold 3 includes a mold upper mold 3a and a mold lower mold 3b.

  According to the resin mold shaft manufacturing method of the present invention, since the shaft body 1 is used, the intermediate position between the gates 6 and 6 adjacent to each other in the circumferential direction of the mold 3 corresponds to the smooth portion 4. In combination with the setting on the outer peripheral side of the shaft body 1 so as to come to the circumferential position, the resin mold so as to suppress the occurrence of stress concentration on the weld portion 5 of the resin molded body 7 of the resin mold shaft material obtained. A shaft material can be manufactured.

  In the resin mold shaft manufacturing method of the present invention, the anti-slip portion 2 may be formed by knurling as shown in FIG. 1 or formed by indentation as shown in FIG. Also good.

  In the method for manufacturing a resin mold shaft according to the present invention, the number of gates 6 provided in the mold upper mold 3a is not particularly limited, and is appropriately set according to the size of the resin mold shaft to be manufactured. Can be done.

  The inner diameter of the gate 6 of the upper mold 3 a can be set as appropriate according to the outer diameter of the pipe 9. Further, the gate 6 of the upper mold 3a has the same angle of the central angle formed by the inner center and the gates 6 and 6 adjacent to each other in the circumferential direction with the inner center of the mold 3 as the apex angle. It is arranged at such a position.

In the resin mold shaft manufacturing method of the present invention, the resin molding material is then ejected simultaneously and at the same speed from each gate 6 of the mold 3 set in the step (2), and the mold 3 is filled with the material. By filling, the outer peripheral surface of the shaft body 1 is covered with the resin molded body 7 [step (3)]. Specifically, as shown in FIGS. 4A and 4B, a resin molding material is obtained from a pipe 9 (P, P _{1 to} P ₆ ) connected to the gate 6 of the upper mold 3a. The inside of the mold 3 (the gap 8 in FIG. 4) is filled with a resin molding material.

  The filling speed when filling the mold 3 with the resin molding material can be appropriately set according to the viscosity of the resin molding material and the like. Moreover, in the manufacturing method of the resin mold shaft material of this invention, the resin molding material is ejected from each gate 6 simultaneously and at the same speed. Thereby, the weld part 5 is formed in the intermediate position between the gates 6 and 6 adjacent in the circumferential direction. In this way, the die 3 having the gates 6 at a plurality of positions in the circumferential direction is attached to the shaft body 1 in which the anti-slip processed portions 2 and the smooth portions 4 are alternately formed in the circumferential direction with respect to the outer peripheral surface. The mold 3 is filled with a resin molding material in a state where the intermediate position between the gates 6 and 6 adjacent to each other in the direction is at the circumferential position corresponding to the smooth portion 4, thereby moving to the weld portion 5. The occurrence of stress concentration is suppressed. As a result, the occurrence of breakage of the resin molded body 7 due to a difference in linear expansion coefficient between the shaft body 1 and the resin molded body 7 caused by a change in temperature is suppressed. Further, according to the method of manufacturing a resin mold shaft material of the present invention, it is not necessary to consider damage due to stress concentration on the weld portion, and the magnet can be thinned, so that the torque detection device can be reduced in size at low cost. it can.

  In the manufacturing method of the resin mold shaft material of the present invention, the outer peripheral surface of the shaft body 1 is covered with the resin molded body 7 by filling the mold 3 with the resin molding material. The outer peripheral surface of the shaft body 1 is covered with a resin molded body 7 by a method according to the type of resin contained in the resin molding material used. For example, when the resin is a thermosetting resin, examples of the method include a method of keeping the resin molding material at the curing temperature of the resin after filling the mold 3 with the resin molding material. For example, when the resin is a thermoplastic resin, the method includes filling the mold 3 with a resin molding material heated to a temperature equal to or higher than the melting point of the resin, and then adding the resin molding material to the melting point of the resin. A method of keeping the temperature at a temperature lower than that can be mentioned.

  According to the method for manufacturing a resin mold shaft material of the present invention, as the resin molding material, a bonded magnet molding material is ejected simultaneously from each gate 6 at the same speed, and the inside of the mold 3 is filled with the material. The outer peripheral surface of the shaft body 1 can be covered with the bond magnet, and a resin mold shaft suitable for the rotor of the torque detector can be obtained.

According to another aspect of the present invention, a first shaft and a second shaft connected coaxially, a bond magnet formed on an outer peripheral surface of the first shaft, and a magnetic circuit in the magnetic field of the bond magnet A torque detection device comprising a plurality of soft magnetic bodies attached to the second shaft and a detector for detecting magnetic flux generated by the soft magnetic bodies,
Anti-slip processing portions for preventing the bond magnet from slipping with respect to the first shaft and smooth portions not performing the anti-slip are alternately formed in the circumferential direction with respect to the outer peripheral surface of the first shaft. The torque detecting device (Embodiment 1) is characterized in that the smoothing portion is disposed at a circumferential position corresponding to a weld portion of the bond magnet.

  In the torque detection device of the present invention, an anti-slip processing portion for preventing the bond magnet from slipping with respect to the first shaft, and a smooth portion not performing the anti-slip operation with respect to the outer peripheral surface of the first shaft. Since the smooth portions are alternately formed in the circumferential direction, and the smooth portions are arranged at circumferential positions corresponding to the weld portions of the bond magnet, even if there is a change in temperature such as the temperature, the bond magnet may be damaged. It is suppressed and exhibits high durability. Further, in the torque detection device of the present invention, it is not necessary to consider damage due to stress concentration on the weld portion, and the magnet can be thinned. Therefore, the torque detection device can be downsized at low cost.

  FIG. 5 is a schematic explanatory diagram showing the configuration of the torque detection device according to the first embodiment of the present invention. FIG. 5A is an exploded perspective view, and FIG. 5B is a longitudinal sectional view.

  In the torque detection device according to the first embodiment of the present invention, the first shaft 101 and the second shaft 102 are coaxially connected via a small-diameter torsion bar 103. The first shaft 101 and the second shaft 102 are connected to the torsion bar 103 by pins 109, respectively.

  The first shaft 101 has a bonded magnet 105 formed on the outer peripheral surface of the first shaft 101. The bond magnet 105 has S poles and N poles alternately in the circumferential direction.

  Two soft magnetic bodies 104 a and 104 b that surround the bonded magnet 105 with an appropriate gap in the radial direction are coaxially fixed to the second shaft main body 102. In the soft magnetic bodies 104a and 104b, twelve isosceles triangular claws 110 extending in one direction perpendicular to the plate surface are provided around a plate-like ring at equal intervals. The two soft magnetic bodies 4a and 4b are opposed to each other so that the respective claws 110 are displaced at appropriate intervals in the circumferential direction.

  The soft magnetic bodies 104a and 104b are arranged in a magnetic field generated corresponding to the positions of the south pole and the north pole of the bond magnet 105, and one or a plurality of detectors 106 that detect a magnetic flux generated in a gap between them. Is inserted into the gap.

  An example of the detector 106 is a Hall IC. The detector 106 is fixed to the housing, for example, and the lead wire 107 of the detector 106 is soldered to the substrate, for example, and supplies power to operate the detector 6, and outputs detected by the detector 106. It has gained. The soft magnetic bodies 104a and 104b are arranged so that the tips of the respective claws 110 point to the boundary between the north pole and the south pole of the bond magnet 105 in a neutral state where no torque is applied.

  In the torque detection device according to the first embodiment of the present invention, when no torque is applied to the first shaft 101 or the second shaft 102, the claws 110 of the soft magnetic bodies 104a and 104b are as shown in FIG. The area of the bonded magnet 105 facing the north and south poles is equal, and the magnetic flux entering from the north pole and the magnetic flux exiting to the south pole are equal, so that a magnetic flux is generated between the soft magnetic body 104a and the soft magnetic body 104b. Absent.

  When a one-way torque is applied to the first shaft 101 or the second shaft 102, the torsion bar 103 is twisted, and the claws 110 of the soft magnetic bodies 104a and 104b and the N pole and S pole of the bond magnet 105 Change. At this time, for example, as shown in FIG. 6A, the area of the soft magnetic body 104a facing the claws 110 is larger in the N pole than in the S pole, and the magnetic flux entering from the N pole is in the S pole. It becomes larger than the magnetic flux which goes out. In addition, the area of the soft magnetic body 104b facing the claws 110 is smaller in the N pole than in the S pole, and the magnetic flux entering from the N pole is smaller than the magnetic flux exiting the S pole. As a result, a magnetic flux is generated from the soft magnetic body 104a to the soft magnetic body 104b, and the magnetic flux density of the magnetic flux increases as the difference between the areas of the N and S poles facing each claw 110 increases.

  On the other hand, when a torque in the other direction is applied to the first shaft 101 or the second shaft 102, the torsion bar 103 is twisted in the opposite direction to the above, and the claws 110 and the bonds of the soft magnetic bodies 104a and 104b are bonded. The relative position of the magnet 105 with respect to the S pole and the N pole changes. At this time, for example, as shown in FIG. 6C, the area of the soft magnetic body 104a facing the claws 110 is smaller in the N pole than in the S pole, and the magnetic flux entering from the N pole is in the S pole. It becomes smaller than the magnetic flux which goes out. Further, the area of the soft magnetic body 104b facing the claws 110 is larger in the N pole than in the S pole, and the magnetic flux entering from the N pole is larger than the magnetic flux exiting in the S pole. As a result, a magnetic flux is generated from the soft magnetic body 104b to the soft magnetic body 104a, and the magnetic flux density of the magnetic flux increases as the difference in area between the N pole and the S pole facing each claw 110 increases.

  The change in magnetic flux density generated in the gap between the soft magnetic body 104 a and the soft magnetic body 104 b is expressed by an electrical angle −180 to 180 deg. If it is illustrated corresponding to (mechanical angle-15-15 deg.), It becomes a sine wave shape as shown in FIG. The range actually used is -90 to 90 deg. The magnetic flux density corresponding to the applied torque can be detected. That is, the applied torque can be known based on the detected magnetic flux density.

  The torque detection device of the present invention may further include a plurality of auxiliary soft magnetic bodies that are magnetically coupled to the soft magnetic body and induce a magnetic flux from the soft magnetic body. In this case, the detector detects the magnetic flux generated in the auxiliary soft magnetic body (Embodiment 2).

  FIG. 7 is a schematic explanatory diagram showing the configuration of the torque detection device according to the second embodiment of the present invention. FIG. 7A is an exploded perspective view, and FIG. 7B is a longitudinal sectional view. This torque detecting device includes two auxiliary soft magnetic bodies 108 and 108 that are magnetically coupled to the soft magnetic bodies 104a and 104b, respectively, and that induce magnetic fluxes from the soft magnetic bodies 104a and 104b, respectively. The auxiliary soft magnetic bodies 108 and 108 are arranged in parallel and have flat plate-like portions that are closer to each other than the other portions, and one or more detectors 106 are inserted in the gaps between the adjacent portions. For example, the auxiliary soft magnetic bodies 108 are fixed to the housing in a magnetically insulated state.

  In the torque detector of the second embodiment, the magnetic flux generated in the soft magnetic bodies 104a and 104b is induced by the auxiliary soft magnetic bodies 108 and 108, respectively, and the induced magnetic flux is close to the auxiliary soft magnetic bodies 108 and 108. It concentrates on the part to be detected and is detected by the detector 106. By the auxiliary soft magnetic bodies 108 and 108, the detector 106 can detect the average of the magnetic flux density generated on the entire circumference of the soft magnetic bodies 104a and 104b.

  In the torque detection device according to the second embodiment, a plurality of soft magnetic bodies (for example, soft magnetic bodies 104 a and 104 b in FIG. 7) are fixed to the second shaft 102. The soft magnetic bodies 104a and 104b are arranged in a magnetic field generated corresponding to the positions of the south pole and the north pole of the bonded magnet 105 to form a magnetic circuit. A plurality of auxiliary soft magnetic bodies (for example, the auxiliary soft magnetic body 108 in FIG. 7) are magnetically coupled to the soft magnetic bodies (for example, the soft magnetic bodies 104a and 104b in FIG. 7), and the soft magnetic body For example, the magnetic flux from the soft magnetic bodies 104a and 104b in FIG. 7 is induced. The detector 106 detects the magnetic flux induced by the auxiliary soft magnetic material (for example, the auxiliary soft magnetic material 108 in FIG. 7). Thus, when torque is applied to the first shaft 101 or the second shaft 102, the torque is detected based on the output of the detector 106.

FIG. 1 is a schematic explanatory view showing an embodiment of a rotor which is an example of a resin mold shaft material of the present invention. FIG. 2 is a schematic explanatory view showing an embodiment of a rotor which is an example of the resin mold shaft material of the present invention. FIG. 3 is a schematic explanatory view showing a conventional bonded magnet-integrated rotor. FIG. 4 is a schematic explanatory view showing one embodiment of the method for producing the resin mold shaft material of the present invention. It is a schematic explanatory drawing which shows the structure of the torque detection apparatus of Embodiment 1 of this invention. It is a schematic explanatory drawing which shows operation | movement of the torque detection apparatus of Embodiment 1 of this invention. It is explanatory drawing which shows the structure of the torque detection apparatus of Embodiment 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shaft body 2 Anti-slip processing part 3 Mold 4 Smooth part 5 Weld part 6 Gate 7 Resin molding 8 Gap 9 Pipe 101 1st axis | shaft 102 2nd axis | shaft 103 Torsion bar 104a, 104b Soft magnetic body 105 Bond magnet 106 Detector 107 Lead wire 108 Auxiliary soft magnetic material 109 Pin 110 Nail

Claims (5)

A resin mold shaft material in which the outer peripheral surface of the shaft body is covered with a resin molded body,
Non-slip processing portions for preventing slip of the resin molded body with respect to the shaft main body and smooth portions not performing the anti-slip are alternately formed in the circumferential direction with respect to the outer peripheral surface of the shaft main body, The said smooth part is arrange | positioned in the circumferential direction position corresponding to the weld part of the said resin molding, The resin mold shaft material characterized by the above-mentioned.   The resin-molded shaft member according to claim 1, wherein the anti-slip portion is formed by knurling or indentation.   The resin molded shaft member according to claim 1 or 2, wherein the resin molded body is formed of a bonded magnet having S poles and N poles alternately in a circumferential direction. The manufacturing method of the resin mold shaft material which covers the outer peripheral surface of a shaft main body with a resin molding including the following process (1)-(3).
(1) An anti-slip portion for preventing the resin molded body from slipping with respect to the shaft main body and a smooth portion not performing the anti-slip are alternately arranged in a circumferential direction with respect to the outer peripheral surface of the shaft main body. Forming step,
(2) A mold having gates at a plurality of positions in the circumferential direction is obtained in the step (1) so that an intermediate position between adjacent gates in the circumferential direction comes to a circumferential position corresponding to the smooth portion. A step of setting on the outer peripheral side of the shaft body; and (3) filling the inside of the mold with a resin molding material simultaneously and at the same speed from each gate of the mold set in the step (2). By covering the outer peripheral surface of the shaft body with the resin molded body A first shaft and a second shaft connected coaxially, a bond magnet formed on the outer peripheral surface of the first shaft, and attached to the second shaft to form a magnetic circuit within the magnetic field of the bond magnet A torque detection device comprising a plurality of soft magnetic bodies and a detector for detecting magnetic flux generated in the soft magnetic bodies,
Anti-slip processing portions for preventing the bond magnet from slipping with respect to the first shaft and smooth portions not performing the anti-slip are alternately formed in the circumferential direction with respect to the outer peripheral surface of the first shaft. The torque detecting device is characterized in that the smooth portion is disposed at a circumferential position corresponding to a weld portion of the bond magnet.

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