JP2005124255A - Rotary shaft of motor, its thrust bearing structure, motor with reduction gear and process for manufacturing rotary shaft of motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for manufacturing a rotary shaft of motor for manufacturing a high precision rotary shaft of motor while reducing the cost. <P>SOLUTION: An armature shaft 7 is provided, at one end thereof, with a surface 14a abutting against a resin member 30 provided on the gear housing 21 of a motor 1 and bearing its thrust load. The thrust bearing surface 14a is formed by burnishing a rough cutting surface of a specified shape. The armature shaft 7 also has a worm 13 meshing with a worm wheel 23. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a motor rotating shaft, a thrust bearing structure for the motor rotating shaft, a motor with a reduction gear, and a method for manufacturing the motor rotating shaft.

Conventionally, as a thrust bearing structure of a motor rotating shaft in a motor, a resin member is provided at the shaft end of the motor rotating shaft that is rotatably supported by the motor housing, and the thrust force of the motor rotating shaft is received by this resin member. Those are known (for example, see Patent Document 1). The resin member is formed by injecting a molten resin into the cavity and curing it with the tip of the motor rotation shaft inserted into the cavity of the motor housing. Since the resin member shrinks along the tip when cured, a slight gap is formed between the resin and the tip, and the motor rotation shaft can be rotated and correctly positioned in the thrust direction. The tip of the motor rotating shaft is manufactured by, for example, forming a predetermined shape (cutting surface) by rough cutting, and then performing finish cutting by replacing the cutting blade with a finer one.
Japanese Patent Publication No. 61-56701

  However, as is well known, the surface of the machined part by cutting is a rough surface where the cutting traces of the cutting blade remain, so even in the case of finish cutting, the cutting trace remains on the cutting surface and the surface roughness of the tip surface is highly accurate. It was difficult to obtain a degree (very small surface roughness). Further, since cutting powder is generated by cutting, there is a possibility that the cutting powder adheres to the motor rotation shaft and enters between the front end surface of the motor rotation shaft and the resin member when the motor is assembled.

  If the surface roughness of the tip surface of the motor rotation shaft is large or if cutting powder enters between the tip surface and the thrust bearing part, the rotational resistance during motor rotation will increase, causing abnormal noise and vibration. In addition, there is a problem in that uneven wear of the resin member is generated, and rattling occurs when the motor rotates. Moreover, in order to suppress the generation | occurrence | production of the malfunction resulting from cutting powder, in order to remove cutting powder, the cleaning process is required, for example, and the raise of manufacturing cost was caused.

The present invention has been made in view of the above problems, and a first object is to provide a high-precision motor rotation shaft, a thrust bearing structure for the motor rotation shaft, and a motor with a reduction gear.
A second object is to provide a method of manufacturing a motor rotating shaft that can manufacture a highly accurate motor rotating shaft while reducing costs.

  In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that a thrust receiving surface that is rotatably supported by a motor housing and abuts against a thrust receiving member provided in the housing and receives the thrust load. A motor rotating shaft at one end, wherein the thrust receiving surface is a burnishing surface obtained by burnishing a cutting surface having a predetermined shape by rough cutting.

According to a second aspect of the present invention, the motor rotating shaft according to the first aspect has a worm that meshes with a worm wheel.
According to a third aspect of the present invention, there is provided a housing that rotatably supports the motor rotation shaft, a housing portion into which a tip of the motor rotation shaft is inserted, a housing portion that is provided in the housing portion, and is formed from the motor rotation shaft. A thrust bearing structure of a motor rotating shaft provided with a resin member that receives a thrust force, wherein the motor rotating shaft is formed with a thrust receiving surface that contacts the resin member and receives the thrust load, the thrust receiving surface Is characterized by comprising a burnished surface obtained by burnishing a cut surface having a predetermined shape by rough cutting.

  According to a fourth aspect of the present invention, in the thrust bearing structure of the motor rotating shaft according to the third aspect, the resin member is injected and cured into the housing portion from an opening formed in communication with the housing portion. The injection resin is provided.

  According to a fifth aspect of the present invention, in the thrust bearing structure for the motor rotating shaft according to the third aspect, the resin member communicates with a resin cap that covers a thrust receiving surface of the motor rotating shaft and the accommodating portion. An injection resin that is injection-hardened between the housing portion and the resin cap from the formed opening is provided.

  According to a sixth aspect of the present invention, there is provided a housing portion formed in a housing for housing a worm wheel that rotatably supports a motor rotating shaft having a worm and meshes with the worm and decelerates and outputs the worm wheel. A resin member that receives a thrust force from the motor rotation shaft, and a motor rotation shaft that is rotatably supported by the housing and has a thrust receiving surface that contacts the resin member and receives the thrust load at one end. The thrust receiving surface comprises a burnished surface obtained by applying burnishing to a cutting surface having a predetermined shape by rough cutting.

  According to a seventh aspect of the present invention, in the motor with a reduction gear according to the sixth aspect, the resin member is made of an injection resin that is injected and hardened into the housing portion from an opening formed in communication with the housing portion. It is characterized by having.

  According to an eighth aspect of the present invention, in the motor with a reduction gear according to the sixth aspect, the resin member is formed in communication with the housing portion and a resin cap that covers a thrust receiving surface of the motor rotation shaft. An injection resin that is injection-hardened between the housing portion and the resin cap from the opening is provided.

  According to a ninth aspect of the present invention, there is provided a motor rotary shaft that is rotatably supported by a motor housing and has a thrust receiving surface at one end that abuts against a thrust receiving member provided on the housing and receives the thrust load. In the manufacturing method, after forming a cutting surface of a predetermined shape by cutting at one end of the motor rotation shaft, the cutting surface is burnt to form the thrust receiving surface as a burnishing surface. And

  A tenth aspect of the present invention is the method of manufacturing a motor rotating shaft according to the ninth aspect, wherein the burnishing is performed by pressurizing the cutting surface with a predetermined pressing force by a pressing member. .

  The invention according to claim 11 is the method of manufacturing the motor rotating shaft according to claim 10, wherein the pressing force applied to the cutting surface of the pressure member is deflected to the motor rotating shaft by the pressure of the pressure member. It is characterized by being set to a predetermined value that does not cause deformation.

According to a twelfth aspect of the present invention, in the method for manufacturing a motor rotating shaft according to the tenth or eleventh aspect, the contact portion that contacts the cutting surface of the pressure member is substantially spherical.
According to a thirteenth aspect of the present invention, in the motor rotating shaft manufacturing method according to any one of the tenth to twelfth aspects, the contact portion that contacts the cutting surface of the pressure member is formed of diamond. It is characterized by being.

(Function)
According to the invention described in claim 1, 3, 6 or 9, the thrust receiving surface of the motor rotating shaft is formed as a burnished surface obtained by applying burnishing to the roughened cutting surface. The generated irregularities such as cutting traces are crushed by burnishing to form a uniform surface. In other words, since the machined surface is smoothed by the cutting marks generated by the cutting tool, the surface roughness becomes a uniform surface with extremely small surface roughness, and the surface roughness is remarkably improved compared to the case where cutting is performed as a finishing process. In addition, the rotational resistance during motor rotation is reduced. In addition, since the thrust receiving surface is finished by burnishing (plastic processing) instead of cutting, surface roughness can be improved without generating cutting powder, and the thrust receiving surface and thrust receiving surface of the motor rotating shaft can be improved. Cutting powder is prevented from being sandwiched between the member (resin member). As a result, a high-precision motor rotation shaft can be obtained, and abnormal noise during motor rotation due to surface roughness of the thrust receiving surface and cutting powder sandwiched between the thrust receiving surface and the thrust receiving member (resin member). Generation of vibrations and vibrations, and uneven wear of the thrust receiving member (resin member) can be suppressed to prevent backlash of the motor rotating shaft.

  In addition, the thrust receiving surface is burnished by burnishing the roughened cutting surface, so there is no need for a cleaning process to clean cutting powder when finishing the thrust receiving surface, reducing manufacturing costs. can do.

  According to the second aspect of the present invention, the motor rotation shaft can be meshed with the worm wheel, and when meshed with the worm wheel, a thrust force is generated on the motor rotation shaft as a reaction force. Noise, vibration, and backlash due to uneven wear are prevented and a quiet rotation can be obtained.

  According to invention of Claim 4 or 7, the resin member is equipped with the injection | pouring resin inject | poured into a accommodating part in the state in which the edge part of the one end side of a motor rotating shaft was inserted in the accommodating part, This injection | pouring resin When it is cured, it shrinks along a thrust receiving surface that is made uniform by burnishing. As a result, the thrust position of the motor rotation shaft is adjusted, and the surface of the resin member that contacts the motor rotation shaft can be made uniform, and the backlash of the motor rotation shaft that occurs during motor rotation can be suppressed.

  According to the invention described in claim 5 or 8, by selecting a resin cap having a predetermined shape, the contact surface that contacts the thrust receiving surface of the motor rotation shaft in the resin member (resin cap) is surely made uniform. As compared with the case where the surface roughness of the contact surface is large, the rotational resistance at the time of motor rotation can be reduced more reliably.

  According to the tenth aspect of the present invention, since the rough cut cutting surface is pressed with a predetermined pressing force by the pressurizing member and burnishing is performed, a cutting mark or the like by cutting formed on the cutting surface is used. The uneven shape can be crushed satisfactorily to make a uniform surface.

  According to the eleventh aspect of the present invention, the pressure applied to the cutting surface of the pressure member is set to a predetermined value that does not cause the motor rotation shaft to bend and deform, so that the motor rotation shaft is stably burnished. be able to. In particular, when burnishing is performed while rotating the motor rotation shaft, the surface roughness of the finished surface by burnishing can be further improved. In addition, since an excessive force is not applied to the tool used for burnishing, durability of the apparatus used for burnishing is improved.

  According to the twelfth aspect of the present invention, since the contact portion of the processed member has a substantially spherical shape, even if the cutting surface has a concave or convex shape such as a cutting mark when the cutting surface is burnished, the contact portion is It can move smoothly along this uneven shape, and the workability is improved.

  According to the thirteenth aspect of the present invention, since the portion of the pressure member that contacts the cutting surface is formed of diamond, the cutting surface can be burnished satisfactorily.

ADVANTAGE OF THE INVENTION According to this invention, a highly accurate motor rotating shaft, the thrust bearing structure of a motor rotating shaft, and a motor with a reduction gear can be provided.
In addition, it is possible to provide a method for manufacturing a motor rotating shaft that can manufacture a highly accurate motor rotating shaft while reducing costs.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
Fig.1 (a) shows the motor 1 of this embodiment. The motor 1 of this embodiment is a motor used as a drive source of a vehicle wiper device, and is a motor with a speed reduction mechanism in which a motor main body 2 and a speed reduction unit 3 in which a speed reduction mechanism is accommodated are integrally assembled.

  The motor body 2 is made of a direct current motor and has a bottomed cylindrical yoke housing 4. A pair of magnets 5 are fixed to the inner surface of the yoke housing 4, and an armature (armature) 6 is rotatably accommodated inside the magnets 5. The armature 6 includes an armature shaft 7, a core 8, a winding 9 and a commutator 10.

  The armature shaft 7 as a motor rotating shaft is made of metal, and as shown in FIG. 2, the shaft body 11 is from the base end portion to a predetermined portion from the tip end portion, and the tip end side from the shaft body 11 is the shaft body. A small diameter portion 12 having a smaller diameter than 11, and a worm 13 is formed in the small diameter portion 12. The distal end side of the small diameter portion 12 is a tip bearing portion 14 formed to have a smaller diameter.

  A substantially central portion of the shaft main body 11 is a core fixing portion 11a for fixing the core 8, and a predetermined portion on the tip side of the core fixing portion 11a is a commutator fixing for fixing the commutator 10. This is a portion 11b.

  The base end portion of the shaft body 11 is a base end bearing portion 11c. As shown in FIG. 1A, the base end bearing portion 11 c is a portion that is supported in the radial direction by a sliding bearing 15 that is fixed to the center of the bottom of the yoke housing 4.

  An end portion of the shaft main body 11 (base end bearing portion 11c) is formed with an accommodating recess 11d having a circular cross section for accommodating the steel ball 16 that receives the thrust force of the armature shaft 7.

  Moreover, the front-end | tip part of the shaft main body 11, ie, the approximate center part of the armature shaft 7, becomes the center bearing part 11e. The central bearing portion 11 e is a portion that is supported in the radial direction by a sliding bearing 22 that is fixed to the gear housing 21 of the speed reduction portion 3.

  The distal end side of the central bearing portion 11e is the small-diameter portion 12 having a diameter smaller than that of the shaft body 11. A worm 13 is formed in the small diameter portion 12. The outer diameter of the worm 13 is formed to be smaller than the diameter of the central bearing portion 11e (shaft body 11).

  The tip bearing portion 14 formed at the tip of the small-diameter portion 12 is inserted into an insertion hole 21c as a receiving portion formed in the gear housing 21 as a housing that rotatably supports the armature shaft 7, and the insertion hole 21c. Is supported in the radial direction. An outer peripheral edge is chamfered on the distal end surface of the distal end bearing portion 14, and a thrust receiving surface 14a is formed as a burnishing surface. The tip end portion of the tip bearing portion 14 has a substantially truncated cone shape.

  As shown in FIG. 1B, a resin member 30 as a thrust receiving member is disposed in the insertion hole 21c. The resin member 30 includes a resin cap 31 provided at the distal end portion of the armature shaft 7 and an injection resin 32 provided in a space (accommodating portion) formed by being closed by the resin cap 31 in the insertion hole 21c. It is configured with. As shown in FIG. 1C, a communication hole 21d is formed in the insertion hole 21c so as to communicate with the insertion hole 21c, and the communication hole 21d opens to the outside through an opening 21e. . In addition, the motor bearing structure of the present invention is configured by including the insertion hole 21c as the accommodating portion and the resin member 30.

  The core 8 is fixed to the core fixing portion 11a of the armature shaft 7 and the commutator 10 is fixed to the commutator fixing portion 11b. The winding 9 is wound around the fixed core 8 and the commutator 10. Armature 6 is configured. Further, a steel ball 16 that receives the thrust force of the armature shaft 7 is housed in a partially protruding state in the housing recess 11 d at the base end of the armature shaft 7. In such an armature 6, the base end bearing portion 11 c of the armature shaft 7 is inserted into the slide bearing 15 at the bottom of the yoke housing 4 so that the steel ball 16 contacts the thrust receiving plate 17 attached to the bottom. The magnet 5 is housed in the yoke housing 4 to which the magnet 5 is fixed. The yoke housing 4 (motor main body 2) that houses the armature 6 is assembled to the gear housing 21 (deceleration unit 3).

  The resin member 30 is inserted into the insertion hole 21c in a state in which a resin cap 31 that covers the thrust receiving surface 14a is inserted into the insertion hole 21c at the distal end portion of the distal end bearing portion 14 of the armature shaft 7. The molten injection resin 32 is injected into the space closed by the resin cap 31 through the communication hole 21d from the opening 21e and solidified. The injected resin 32 is solidified and integrated with the resin cap 31 to form the resin member 30.

  The speed reduction unit 3 has a gear housing 21. The gear housing 21 has a cup-shaped predetermined shape including a shaft accommodating portion 21 a that accommodates the distal end side of the armature shaft 7 extending from the motor body 2 and a wheel accommodating portion 21 b that accommodates the worm wheel 23.

  A sliding bearing 22 that supports the central bearing portion 11e of the armature shaft 7 in the radial direction is fixed to the proximal end portion of the shaft housing portion 21a. A distal end portion of the distal end bearing portion 14 of the armature shaft 7 (small diameter portion 12) is inserted into the distal end portion of the shaft housing portion 21a, and an insertion hole 21c for supporting the distal end portion in the radial direction is formed. When the motor body 2 is assembled to the gear housing 21, the distal end side (the worm 13 and the distal end bearing portion 14) of the armature shaft 7 is inserted into the sliding bearing 22 and accommodated in the shaft accommodating portion 21a. At this time, the outer diameter of the worm 13 is smaller than the outer diameter of the central bearing portion 11e, that is, the inner diameter of the sliding bearing 22, so that the worm 13 does not contact the inner peripheral surface of the sliding bearing 22.

  A worm wheel 23 that meshes with the worm 13 of the armature shaft 7 is rotatably accommodated in the wheel accommodating portion 21b. An output shaft 24 is provided on the worm wheel 23 so as to rotate integrally.

  A brush device 25 is fixed to a portion of the gear housing 21 that faces the motor body 2. The brush device 25 holds a power supply brush 26 that is in sliding contact with the commutator 10. The brush device 25 is supplied with power from outside via a power supply line (not shown), and supplies the power to the armature 6 (winding 9) via the power supply brush 26 and the commutator 10. As a result, the armature 6 rotates and the armature shaft 7 rotates, whereby the output shaft 24 is rotated via the worm 13 and the worm wheel 23, and the wiper device is operated based on the rotation of the output shaft 24. It has become.

(Production method)
Next, the manufacturing method of said armature shaft 7 is demonstrated.
The armature shaft 7 is manufactured by processing a cylindrical metal shaft material 40 as shown in FIG. For the shaft material 40, first, a forging die 41 as shown in FIG. 4 is used, the small diameter portion 12 and the distal end bearing portion 14 are formed on the distal end side, and the cold forging is performed so as to form the accommodating recess 11d on the proximal end surface. Processing (cold forging) is performed.

  The forging die 41 is divided into two parts, and a pair of main body molds 41a (only one main body mold 41a is shown in FIG. 4) in which the shaft raw material 40 is disposed, and are pushed into the main body mold 41a. A slide mold 45 is provided. The main body mold 41a is further configured to be divided into three parts of first to third mold parts 42 to 44 in the axial direction of the shaft material 40 (the pushing direction of the slide mold 45). In order to form the armature shaft 7 across the portions 42 to 44, a shaft forming recess 41b is provided. The first mold portion 42 includes a small-diameter portion machining recess 42 a for forging the tip portion of the shaft material 40 to form the small-diameter portion 12 and the tip bearing portion 14. The second mold part 43 and the third mold part 44 include a small-diameter part machining recess 42a and a shaft body support recess 43a for supporting the shaft body 11 when the first mold part 42 forms the small-diameter part 12 in the shaft material 40. 44a constitutes a shaft forming recess 41b.

  On the other hand, the slide mold 45 is slidably provided in the main body mold 41a, that is, in the shaft main body support recess 44a. The slide mold 45 includes a columnar main body 45a having a diameter substantially equal to (slightly smaller than) the inner diameter of the shaft main body supporting recess 44a, and a columnar shape corresponding to the receiving recess 11d at the center of the tip of the main body 45a. Forming convex part 45b which protrudes in is formed.

  Simultaneously with the main body mold 41a, the small diameter portion 12 and the tip bearing portion 14 are formed at the distal end portion of the shaft material 40, and at the same time, the accommodation recess 11d is formed at the proximal end surface of the shaft material 40 by the slide mold 45 Yes.

  Next, as shown in FIG. 5, in order to form the outer peripheral surfaces of the base end bearing portion 11c and the central bearing portion 11e of the shaft body 11 with high accuracy, the grindstone 46 is brought into sliding contact with the entire outer peripheral surface of the shaft body 11, The entire outer peripheral surface of the shaft body 11 is ground. That is, by this grinding process, the surface roughness and roundness of the outer peripheral surfaces of the base end bearing portion 11c and the central bearing portion 11e are improved.

As shown in FIG. 6, the worm 13 is formed by sandwiching the small-diameter portion 12 subjected to cold forging between the rolling dies 47 and rotating or moving the rolling dies 47.
Thereafter, a thrust receiving surface 14 a is formed on the distal end surface of the distal end bearing portion 14.

First, the armature shaft 7 is rotated at a predetermined rotational speed by gripping the proximal end bearing portion 11c side by a known means.
Next, as shown in FIG. 7, the cutting blade 53 is applied while sliding on the distal end surface of the rotating distal end bearing portion 14 to be roughly cut, thereby forming a cutting surface 14 b. The cutting blade 53 is provided in a slide device (not shown) and is slidable in a substantially axial direction of the shaft body 11 and a direction inclined by a predetermined angle from the axial direction. In rough cutting, for example, the cutting blade 53 is moved in the X1 direction toward the tip bearing portion 14 in the axial direction with respect to the rotating tip bearing portion 14, and then moved in the X2 direction inclined by a predetermined angle from the axial direction. The tip bearing portion 14 is cut while moving in the X2 direction. Thereafter, the cutting blade 53 is moved in the X3 direction, which is parallel to the X1 direction and in the reverse direction, and is moved in the X4 direction, which is parallel to the X2 direction and in the reverse direction, and the cutting blade 53 is returned to the original position.

  Thereafter, the cutting blade 53 and the burnishing tool 54 as the pressure member are exchanged in the slide device. In the burnishing tool 54, a contact portion that contacts the cutting surface 14b is a substantially spherical diamond 54a.

  Then, as shown in FIG. 8, the burnishing tool 54 slides against the cutting surface 14 b of the rotating tip bearing portion 14 to form the thrust receiving surface 14 a, and the armature shaft 7 of this embodiment is manufactured. . At this time, the burnishing tool 54 is set to pressurize the armature shaft 7 at a predetermined value that does not cause the armature shaft 7 to bend. The burnishing is performed, for example, with respect to the rotating tip bearing portion 14 (armature shaft 7), after the burnishing tool 54 is moved in the X11 direction toward the tip bearing portion 14 in the axial direction, and then inclined at a predetermined angle from the axial direction. The cutting surface 14b (see FIG. 8) of the tip bearing portion 14 is burnished while moving in the X12 direction. After that, it is moved in the X13 direction, which is parallel to the X11 direction and in the reverse direction, and is moved in the X14 direction, which is parallel to the X12 direction and in the reverse direction, and the burnishing tool 54 is returned to the original position.

(Effect of embodiment)
As described above, this embodiment has the following effects.
(1) In the present embodiment, the thrust receiving surface 14a of the armature shaft is formed as a burnishing surface obtained by applying burnishing to the rough-cut cutting surface 14b. It is crushed by burnishing to make a uniform surface. In other words, since the machined surface does not have the cutting traces of the cutting blade as in the case of cutting, the surface roughness becomes a uniform surface with extremely small surface roughness, and the surface roughness is significantly improved compared to the case where cutting is performed as a finishing process. In addition, the rotational resistance during motor rotation is reduced. Further, since the finishing process of the thrust receiving surface 14a is performed by burnishing (plastic processing) instead of cutting, the surface roughness can be improved without generating cutting powder, and the thrust receiving surface 14a of the armature shaft 7 can be improved. Cutting powder is prevented from being sandwiched between the resin member 30. As a result, a high-precision armature shaft 7 can be obtained, and abnormal noise and vibration during motor rotation caused by the surface roughness of the thrust receiving surface 14a and the cutting powder sandwiched between the thrust receiving surface 14a and the resin member 30. Can be suppressed, and the occurrence of uneven wear of the resin member 30 can be suppressed to prevent the motor rotating shaft from rattling.

  In addition, since the thrust receiving surface 14a is burnished by subjecting the cutting surface 14b by rough cutting to burnishing, a cleaning process for cleaning the cutting powder at the time of finishing the thrust receiving surface 14a is not required. Cost can be reduced.

  (2) In this embodiment, since the armature shaft 7 has the worm 13, it can mesh with the worm wheel 23. Further, in the armature shaft 7 having the worm 13, depending on the direction in which the armature 6 and the worm 13 are formed, the thrust load on the side of the armature shaft 7 where the worm 13 is formed becomes large and the resin member 30 is unevenly worn. There is a fear. Then, when the armature shaft 7 rotates in the forward and reverse directions, the armature shaft 7 and the resin member 30 collide with each other at the time of reversal to generate a reversal sound. However, in this embodiment, the armature shaft 7 is highly accurate, so that it is possible to suppress uneven wear generated in the resin member 30 and to prevent the occurrence of such a reverse sound.

  (3) In the present embodiment, the resin member 30 includes the injection resin 32 that is injected into the insertion hole 21c in a state where the end of the armature shaft 7 on the tip bearing portion 14 side is inserted into the insertion hole 21c. When the injection resin 32 is cured, it shrinks along the thrust receiving surface 14a made uniform by burnishing (shrinks in the imitation state of the thrust receiving surface 14a). As a result, the thrust position of the armature shaft 7 is adjusted, and rattling of the armature shaft 7 that occurs when the motor rotates can be suppressed.

  (4) In this embodiment, by selecting the resin cap 31 having a predetermined shape, the contact surface of the resin member 30 that contacts the thrust receiving surface 14a of the armature shaft 7 can be surely made uniform. Compared with the case where the surface roughness of the contact surface is large, the rotational resistance during motor rotation can be more reliably reduced.

  (5) In this embodiment, since the rough-cut cutting surface 14b is pressed with a predetermined pressing force by the burnishing tool 54, the uneven shape of the cutting trace formed on the cutting surface 14b is crushed well. A uniform surface can be obtained.

  (6) In this embodiment, the pressure applied to the cutting surface 14b of the burnishing tool 54 is set to a predetermined value that does not cause the armature shaft 7 to bend and deform, so that the armature shaft 7 can be burnt stably. it can. In particular, when burnishing is performed while the armature shaft 7 is rotated, the surface roughness of the finished surface (thrust receiving surface 14a) by burnishing can be further improved. Moreover, since an excessive force is not applied to the tool used for burnishing, durability of the apparatus used for burnishing is improved.

  (7) In this embodiment, since the contact portion of the burnishing tool 54 is a substantially spherical diamond 54a, even if the cutting surface 14b has an uneven shape on the cutting surface 14b when the cutting surface 14b is burnished, diamond 54a can move smoothly along this uneven shape, and the workability is improved.

(Another example)
In addition, you may change embodiment of this invention as follows.
In the resin member 30, the portion where the thrust receiving surface 14a of the armature shaft 7 contacts is a preferred example of the resin cap 31, but the portion of the resin member 30 that contacts the thrust receiving surface 14a may be the injected resin. As a result, the injected resin shrinks along the thrust receiving surface 14a made uniform by burnishing when it is cured (shrinks in a state of imitation of the thrust receiving surface 14a), so that it contacts the armature shaft 7 of the resin member. The surface can be a uniform surface, and rattling that occurs when the armature shaft 7 rotates can be suppressed. Further, the resin member is not limited to the injected resin or the resin cap, and may be a resin member of another aspect.

  Although the armature shaft 7 has the worm 13, it may be an armature shaft (motor rotating shaft) that does not have a worm. Even if the armature shaft has no worm, the same effect as that of the present embodiment can be obtained.

  When performing burnishing on the armature shaft 7, the cutting surface 14b was pressurized by the burnishing tool 54 while rotating the armature shaft 7, but the burnishing is not limited to this form. For example, burnishing may be performed without rotating the armature shaft 7.

  The contact portion (diamond 54a) that contacts the cutting surface 14b of the burnishing tool 54 has a substantially spherical shape, but the shape of the contact portion is not limited to this, and may be, for example, a roller member. Further, although the cutting surface 14b is pressed by the diamond 54a, the material of the contact portion is not limited to diamond, and other materials such as a steel ball having a hardness much higher than the metal of the shaft material may be used.

  The thrust receiving surface 14a is formed in the shape of a truncated cone at the tip of the tip bearing portion 14, but the thrust receiving surface is not limited to this shape. For example, the thrust receiving surface 14a may be formed in a cone shape at the tip of the tip bearing portion 14. Good.

(A) is sectional drawing of a motor, (b) is the elements on larger scale of (a), (c) is the sectional view on the AA line of (b). The top view of a motor rotating shaft. (A) And (b) is explanatory drawing of the raw material for shafts. Explanatory drawing of the manufacture procedure of a motor rotating shaft. Explanatory drawing of the manufacture procedure of a motor rotating shaft. Explanatory drawing of the manufacture procedure of a motor rotating shaft. Explanatory drawing of the manufacture procedure of a motor rotating shaft. Explanatory drawing of the manufacture procedure of a motor rotating shaft.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Motor as a motor with a reduction gear, 2 ... Motor main body, 3 ... Deceleration part, 6 ... Armature, 7 ... Armature shaft as a motor rotating shaft, 13 ... Worm, 14a ... Thrust receiving surface, 14b ... Cutting surface, 21 ... Gear housing as housing, 21c ... Insertion hole as accommodating part, 21e ... Opening part, 23 ... Worm wheel, 30 ... Resin member as thrust receiving member, 31 ... Resin cap, 32 ... Injected resin, 54 ... Pressure Burnishing tool as member, 54a ... Diamond as contact part.

Claims (13)

A motor rotating shaft that is rotatably supported by a motor housing and has a thrust receiving surface at one end that abuts against a thrust receiving member provided in the housing and receives the thrust load,
The motor rotating shaft, wherein the thrust receiving surface is a burnishing surface obtained by burnishing a cut surface having a predetermined shape by rough cutting. In the motor rotating shaft according to claim 1,
A motor rotating shaft comprising a worm that meshes with a worm wheel. A housing that rotatably supports the motor rotation shaft, and a housing portion into which the tip of the motor rotation shaft is inserted;
A thrust bearing structure of a motor rotating shaft provided with a resin member provided in the housing portion and receiving a thrust force from the motor rotating shaft;
The motor rotating shaft is formed with a thrust receiving surface that contacts the resin member and receives the thrust load,
A thrust bearing structure for a motor rotating shaft, wherein the thrust receiving surface is a burnished surface obtained by burnishing a cut surface having a predetermined shape by rough cutting. In the thrust bearing structure of the motor rotating shaft according to claim 3,
A thrust bearing structure for a motor rotating shaft, wherein the resin member includes an injection resin that is injected and hardened into an accommodation portion from an opening formed in communication with the accommodation portion. In the thrust bearing structure of the motor rotating shaft according to claim 3,
The resin member is
A resin cap covering a thrust receiving surface of the motor rotation shaft;
A thrust bearing structure for a motor rotating shaft, comprising: an injection resin that is injected and hardened between the storage portion and the resin cap through an opening formed in communication with the storage portion. An accommodating portion formed on a housing for accommodating a worm wheel that rotatably supports a motor rotating shaft having a worm and meshes with the worm to decelerate and output;
A resin member that is provided in the housing and receives a thrust force from the motor rotation shaft;
A motor with a speed reducer, which is rotatably supported by the housing and has a motor rotating shaft at one end that has a thrust receiving surface that contacts the resin member and receives a thrust load thereof,
The motor with a reduction gear, wherein the thrust receiving surface is a burnished surface obtained by burnishing a cut surface having a predetermined shape by rough cutting. The motor with a reduction gear according to claim 6,
The resin member is
A motor with a speed reducer, comprising: an injection resin that is injected and hardened into an accommodation portion from an opening formed in communication with the accommodation portion. The motor with a reduction gear according to claim 6,
The resin member is
A resin cap covering a thrust receiving surface of the motor rotation shaft;
A motor with a speed reducer, comprising: an injection resin that is injected and hardened between the storage portion and the resin cap through an opening formed in communication with the storage portion. A method of manufacturing a motor rotating shaft that is rotatably supported by a motor housing and has a thrust receiving surface at one end that abuts against a thrust receiving member provided in the housing and receives the thrust load,
The motor rotating shaft is characterized in that a cutting surface having a predetermined shape is formed by cutting at one end of the motor rotating shaft, and then the thrust receiving surface is formed as a burnishing surface by applying burnishing to the cutting surface. Production method. In the manufacturing method of the motor rotating shaft according to claim 9,
The method of manufacturing a motor rotating shaft, wherein the burnishing is performed by pressurizing the cutting surface with a predetermined pressure with a pressurizing member. In the manufacturing method of the motor rotating shaft according to claim 10,
A method of manufacturing a motor rotating shaft, wherein the pressing force applied to the cutting surface of the pressing member is set to a predetermined value that does not cause bending deformation of the motor rotating shaft by pressing of the pressing member. In the manufacturing method of the motor rotating shaft according to claim 10 or 11,
A method of manufacturing a motor rotating shaft, wherein a contact portion of the pressing member that contacts the cutting surface is substantially spherical. In the manufacturing method of the motor rotating shaft according to any one of claims 10 to 12,
The method of manufacturing a motor rotating shaft, wherein a contact portion that contacts the cutting surface of the pressure member is formed of diamond.

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