Motor device

Abstract

To eliminate the need for subsequent deburring work or the like by suppressing the occurrence of burrs when assembling.SOLUTION: A revolving shaft 32 comprises: a columnar part 33a whose outer diameter is constant in the axial direction of the revolving shaft 32; a tapered part 33b, which is arranged in the one side of axial direction of the columnar part 33a, and whose outer diameter is gradually smaller as it leaves the columnar part 33a; and an arc-shaped connection part 33c arranged between the columnar part 33a and the tapered part 33b. The arc-shaped connection part 33c connects the outer peripheral surface of the columnar part 33a to the outer peripheral surface of the tapered part 33b on the arc surface when the revolving shaft 32 is seen from outside in the radial direction. A holder member 61 comprises: a cylindrical body part 61a in which the columnar part 33a is pressed; and a space forming cylinder part 61b, which is arranged in the one side of axial direction of the cylindrical body part 61a, forming a space SP between the cylindrical body part 61a and the arc-shaped connection part 33c in the radial direction of the revolving shaft 32.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a motor device having a rotating shaft and a fixed component fixed to the rotating shaft. [Background technology]

[0002] For example, Patent Document 1 describes a wiper motor that has an armature shaft with a bearing member mounting portion and a guide small diameter portion that is smaller in diameter than the bearing member mounting portion, and in which the inner race of a ball bearing is fixed to the bearing member mounting portion by press-fitting. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-185663 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology described in Patent Document 1, when fixing a ball bearing to a bearing member mounting portion, a small diameter guide portion is inserted into an inner race that forms the ball bearing, and then the bearing member mounting portion is press-fitted via a step between the small diameter guide portion and the bearing member mounting portion.

[0005] Therefore, when the bearing member mounting portion of the armature shaft is inserted into the inner race of the ball bearing, the press-fit load on the armature shaft increases rapidly, which can cause the corners between the bearing member mounting portion and the step to be scraped, or the inner wall of the inner race to be scraped, resulting in the generation of so-called "burrs (shavings)."

[0006] An object of the present invention is to provide a motor device that can suppress the generation of burrs during assembly and eliminate the need for subsequent deburring work, etc. [Means for solving the problem]

[0007] One aspect of the motor device is a motor device having a rotating shaft and a fixed part fixed to the rotating shaft, wherein the rotating shaft comprises a straight section having a constant outer diameter in the axial direction of the rotating shaft, a tapered section provided on one axial side of the straight section and having an outer diameter that gradually decreases with increasing distance from the straight section, and a connecting section provided between the straight section and the tapered section, wherein the connecting section connects the outer surface of the straight section and the outer surface of the tapered section with an arcuate surface when the rotating shaft is viewed from the outside in the radial direction, and the fixed part has a press-fit cylindrical section into which the straight section is press-fitted, and a gap-forming cylindrical section provided on one axial side of the press-fit cylindrical section and forming a gap between it and the connecting section in the radial direction of the rotating shaft. [Effects of the Invention]

[0008] According to the present invention, it is possible to realize a motor device that can suppress the generation of burrs during assembly and eliminate the need for subsequent deburring work, etc. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a perspective view of the motor device as seen from the bracket side. [Figure 2] FIG. 2 is a perspective view of the motor device as seen from the case side. [Figure 3] FIG. 2 is a cross-sectional view showing the internal structure of the motor device. [Figure 4] FIG. 4 is a cross-sectional view showing only the rotor of FIG. 3. [Figure 5] FIG. 2 is a perspective view showing the rotating shaft alone. [Figure 6] FIG. 2 is a perspective view of the magnet unit as seen from the rotor body side. [Figure 7] FIG. 2 is a perspective view of the magnet unit as seen from the pinion gear side. [Figure 8] FIG. 4 is an enlarged cross-sectional view showing a structure for fixing a magnet unit to a rotation shaft. [Figure 9]FIG. 10 is an assembly explanatory diagram showing the [parts setting process]. [Figure 10] FIG. 10 is an assembly explanatory diagram showing the rotation axis moving step. [Figure 11] FIG. 10 is an assembly explanatory diagram showing the press-fitting process. [Figure 12] 10A and 10B are diagrams illustrating an assembled state of the present embodiment. [Figure 13] FIG. 9 is a diagram corresponding to FIG. 8 and showing a comparative example. [Figure 14] FIG. 10 is a diagram illustrating an assembled state of a comparative example. [Figure 15] FIG. 10 is a diagram corresponding to FIG. 8 and showing a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0011] <Motor device> FIG. 1 is a perspective view of the motor device as seen from the bracket side, FIG. 2 is a perspective view of the motor device as seen from the case side, and FIG. 3 is a cross-sectional view showing the internal structure of the motor device.

[0012] The motor device 10 shown in Figures 1 to 3 is used, for example, as a drive source for an electric brake device mounted on a vehicle such as an automobile. The motor device 10 is a brushless motor and includes a metal case 20. The case 20 is formed into a cylindrical shape with a bottom by deep drawing a metal plate or the like. The case 20 includes a cylindrical portion 21, and an opening 22 is provided on one axial side of the cylindrical portion 21 (the upper side in Figure 3). Meanwhile, a bottom wall portion 23 is provided on the other axial side of the cylindrical portion 21 (the lower side in Figure 3).

[0013] A plurality of flanges 24 protruding radially outward are provided on the opening 22 side of the cylindrical portion 21, and these flanges 24 are attached to the other axial side (the lower side in FIG. 3) of the resin bracket 40 by a total of three first male screw members S1. Each flange 24 is provided with a first insertion hole H1 through which the first male screw member S1 is inserted, and a second insertion hole H2 through which a fixing bolt (not shown) for fixing the motor device 10 to a driven object (such as an electric brake device) is inserted.

[0014] In this way, the opening 22 of the metal case 20 is closed by the resin bracket 40. The first male screw member S1 is tightened with a Phillips (+) screwdriver (not shown) at the tip end.

[0015] <Stator> As shown in Fig. 3, a stator 25 is housed inside the case 20. Specifically, the stator 25 is fixed by press-fitting into the radially inner side of the cylindrical portion 21. The stator 25 includes a stator core 26 formed in a generally cylindrical shape, and the stator core 26 is formed by laminating a plurality of thin steel plates. The stator core 26 includes a core body 26a formed in a generally cylindrical shape and a plurality of teeth 26b protruding radially inward from the core body 26a.

[0016] Resin insulators 27 are attached to each of the plurality of teeth 26b, and coils 28 consisting of U-phase, V-phase, and W-phase are wound around the outside of the insulators 27 in a predetermined winding manner and with a predetermined number of turns. That is, the three-phase coils 28 are wound around each of the plurality of teeth 26b via the insulators 27, which function as insulators. The three-phase coils 28 are arranged alternately in the circumferential direction of the stator 25 so as to form U-phase, V-phase, W-phase, etc.

[0017] An annular busbar unit 29 is attached to one axial side (upper side in FIG. 3) of the stator 25. The busbar unit 29 includes a plurality of conductive members 30 corresponding to the U-phase, V-phase, and W-phase, and these conductive members 30 are held by an annular holding member 29a. The holding member 29a is made of an insulator such as plastic and prevents the conductive members 30 from shorting out.

[0018] An end of the three-phase coil 28 is electrically connected to one end of each conductive member 30. Meanwhile, an end of the power supply terminal PT provided on the bracket 40 is electrically connected to the other end of each conductive member 30.

[0019] Here, three power supply terminals PT are provided corresponding to the U phase, V phase, and W phase, and the other ends of these power supply terminals PT are exposed inside the connector connection part CN to which a connector member (not shown) on the vehicle side is connected.

[0020] <Rotor> Figure 4 is a cross-sectional view showing only the rotor in Figure 3, Figure 5 is a perspective view showing the rotating shaft alone, Figure 6 is a perspective view of the magnet unit seen from the rotor body side, Figure 7 is a perspective view of the magnet unit seen from the pinion gear side, and Figure 8 is an enlarged cross-sectional view showing the structure for fixing the magnet unit to the rotating shaft.

[0021] 3 and 4, the motor device 10 includes a rotor 31 that rotates relative to the stator 25. The rotor 31 has a rotating shaft 32 and a rotor body .

[0022] <Rotation axis> 4 and 5, the rotating shaft 32 is made of a machine structural alloy steel, such as "SNCM420," that has been heat-treated by carburizing, quenching, and tempering, and is formed into a stepped shape by cutting and grinding the outer periphery of a round steel bar (material). That is, the rotating shaft 32 is a cut / ground product, and its hardness (Vickers hardness) is approximately "700 Hv."

[0023] Specifically, the rotating shaft 32 includes a large diameter portion 32a, a medium diameter portion 33 having a smaller diameter than the large diameter portion 32a, and a small diameter portion 32b having a smaller diameter than the medium diameter portion 33. As shown in Fig. 3, the rotating shaft 32 passes through a through-hole 52 provided in the sensor board 50 and is disposed so as to cross the bracket 40.

[0024] The large diameter portion 32a is disposed on the other axial side (right side in FIG. 5) of the rotating shaft 32, and occupies approximately half of the rotating shaft 32 in the axial direction. A rotor core 35 forming the rotor body 34 is press-fitted and fixed to the outer periphery of the large diameter portion 32a. This causes the rotating shaft 32 to rotate together with the rotor core 35. A bearing support portion 32c is provided on the other axial side (right side in FIG. 5) of the large diameter portion 32a, and the bearing support portion 32c is rotatably supported by a first bearing BR1 (see FIG. 3).

[0025] Furthermore, medium diameter section 33 is disposed on one axial side (left side in FIG. 5) of large diameter section 32a, and its axial length is approximately ¼ of the axial length of large diameter section 32a. A magnet unit 60 (see FIGS. 6 and 7) is fixed to the outer periphery of medium diameter section 33. Here, magnet unit 60 is used to detect the rotation state of rotor 31 (rotating shaft 32) and rotates together with rotating shaft 32.

[0026] Furthermore, the small diameter portion 32b is disposed on one axial side (the left side in FIG. 5) of the medium diameter portion 33, and its axial length is approximately 1.5 times the axial length of the medium diameter portion 33. The small diameter portion 32b is rotatably supported by a second bearing BR2 (see FIG. 3). Note that the pair of first and second bearings BR1 and BR2 that rotatably support both axial ends of the rotating shaft 32 each employs a ball bearing (not shown in detail).

[0027] Furthermore, a pinion gear portion 32d that forms an output portion of the motor device 10 is integrally provided on one axial side (the left side in FIG. 5) of the small diameter portion 32b. Specifically, the pinion gear portion 32d is connected to, for example, a feed screw shaft (not shown) that moves a piston of an electric brake device back and forth so as to be capable of transmitting power.

[0028] <Medium diameter part> 8, the medium diameter portion 33 to which the magnet unit 60 is fixed has a cylindrical portion 33a, a tapered portion 33b, and an arc-shaped connecting portion 33c. Specifically, the cylindrical portion 33a extends straight in the axial direction of the rotating shaft 32 so that the outer diameter is constant, and is the portion with the largest outer diameter in the medium diameter portion 33. A cylindrical main body portion 61a of a holder member 61 that forms the magnet unit 60 is fixed by press-fitting into the cylindrical portion 33a.

[0029] The cylindrical portion 33a corresponds to the straight portion in the present invention.

[0030] Tapered portion 33b is provided on one axial side (left side in FIG. 8) of cylindrical portion 33a, and its outer diameter gradually decreases with increasing distance from cylindrical portion 33a. Specifically, tapered portion 33b has a truncated cone shape in which the cross-sectional area in a direction perpendicular to the axial direction of rotating shaft 32 gradually decreases toward one axial side (left side in FIG. 8) of rotating shaft 32. Magnet unit 60 is press-fitted into cylindrical portion 33a from one axial side of tapered portion 33b (see FIGS. 9 to 11).

[0031] Furthermore, the arc-shaped connecting portion 33c is provided between the cylindrical portion 33a and the tapered portion 33b in the axial direction of the rotation axis 32. Specifically, as shown in FIG. 8, when the rotation axis 32 is viewed from the radially outer side, the outer peripheral portion of the arc-shaped connecting portion 33c is formed in an arc shape with a radius dimension R. Here, the arc-shaped connecting portion 33c has a function of smoothly connecting the cylindrical portion 33a and the tapered portion 33b without a step in the axial direction of the rotation axis 32. That is, the arc-shaped connecting portion 33c connects the outer peripheral surface of the cylindrical portion 33a and the outer peripheral surface of the tapered portion 33b with an arc surface. Thereby, the magnet unit 60 can be easily press-fitted into the cylindrical portion 33a from one axial side of the tapered portion 33b (see FIGS. 9 to 11).

[0032] Note that the arc-shaped connecting portion 33c corresponds to the connecting portion in the present invention.

[0033] Here, a small-diameter portion 32b is disposed on one axial side (the left side in FIG. 8) of the tapered portion 33b. And the outer diameter dimension D1 of the small-diameter portion 32b is smaller than the outer diameter dimension D2 on one axial side of the tapered portion 33b (D1 < D2).

[0034] Also, the length dimension L1 of the arc-shaped connecting portion 33c in the axial direction of the rotation axis 32 is shorter than the length dimension L2 of the tapered portion 33b in the axial direction of the rotation axis 32 (L1 < L2). Further, the length dimension L3 of the cylindrical portion 33a in the axial direction of the rotation axis 32 is longer than the length dimension L2 of the tapered portion 33b in the axial direction of the rotation axis 32 (L3 > L2). That is, when these length dimensions L1 to L3 are shown in the magnitude relationship, it becomes "L1 < L2 < L3".

[0035] [[ID=1 / / ]]

[0036] ​Furthermore, the entire axial length of the arc-shaped connecting portion 33c and a portion of the other axial side (the right side in FIG. 8) of the tapered portion 33b are disposed within the axial range of the gap forming cylindrical portion 61b that forms the holder member 61. In other words, in the radial direction of the rotating shaft 32, the entire arc-shaped connecting portion 33c and a portion of the tapered portion 33b overlap with the gap forming cylindrical portion 61b of the holder member 61.

[0037] Here, the shape of the cylindrical portion 33a is adjusted by "cutting." In contrast, the shapes of the tapered portion 33b and the arc-shaped connecting portion 33c are adjusted by "grinding." In other words, the outer peripheral surfaces of the tapered portion 33b and the arc-shaped connecting portion 33c are smoother than the outer peripheral surface of the cylindrical portion 33a. This makes it easier to press-fit the rotating shaft 32 into the holder member 61, while making it more difficult for the holder member 61 to come off from the rotating shaft 32.

[0038] <Rotor body> 3 and 4, the rotor body 34 fixed to the outer periphery of the large diameter portion 32a includes a rotor core 35 formed in a generally cylindrical shape by laminating a plurality of thin steel plates (ferromagnetic material), and a cylindrical magnet 36 attached to the radially outer side of the rotor core 35. The radially outer side of the magnet 36 is covered with a cylindrical magnet cover 37 made of a stainless steel plate or the like.

[0039] The magnet cover 37 is fixed to the outer periphery of the magnet 36 by crimping one axial side (the left side in FIG. 4) of the magnet cover 37 radially inward. This allows the rotation center of the magnet 36 to precisely coincide with the rotation center of the rotor core 35, thereby suppressing rotational wobble of the rotor 31. In addition, the air gap AG (see FIG. 3) between the rotor body 34 and the stator 25 can be narrowed, allowing for a compact, high-output (high-efficiency) motor device 10 to be realized.

[0040] In order to prevent the clamping force of the magnet cover 37 from being transmitted to the magnet 36, a magnet protection member 38 made of a resin material such as plastic is provided on the other axial side of the magnet cover 37.

[0041] Here, the motor device 10 is not limited to a surface permanent magnet type in which the magnet 36 is attached to the surface of the rotor core 35 as described above, but may also be an interior permanent magnet type in which the magnet is embedded inside the rotor core.

[0042] <bracket> 1 and 3, the bracket 40 serves to secure the motor device 10 to an object to be driven. The bracket 40 is formed into a generally circular disk shape by injection molding a resin material such as molten plastic. In other words, the bracket 40 is an injection-molded product.

[0043] The bracket 40 has a partition wall portion 41 formed in a substantially circular plate shape. The partition wall portion 41 separates the case 20 side (lower side in FIG. 3) from the driven object side (upper side in FIG. 3) in the axial direction of the rotating shaft 32, and an insertion tube portion 42 is integrally provided in the center of the partition wall portion 41, through which the other axial side (upper side in FIG. 3) of the rotating shaft 32 is inserted.

[0044] A bearing holder 43 formed into a substantially cup shape by pressing a steel plate or the like is provided on the radially inner side of the insertion cylindrical portion 42. Specifically, the radially outer side of the bearing holder 43 is fixed to the radially inner side of the insertion cylindrical portion 42.

[0045] The bearing holder 43 is provided with an insertion hole 43a through which the rotating shaft 32 is inserted, and the bearing holder 43 holds the second bearing BR2 so as to be coaxial with the insertion cylindrical portion 42. An annular fixing plate 44 is provided on the other axial side of the second bearing BR2 (the lower side in FIG. 3) to prevent the second bearing BR2 from falling off the bearing holder 43.

[0046] Furthermore, a sensor board 50 is provided on the other axial side (the lower side in FIG. 3) of the insertion tube portion 42. Specifically, the sensor board 50 is fixed to the case 20 side of the partition wall portion 41 by a plurality of second male screw members S2.

[0047] 1, the partition wall 41 is provided with a first terminal hole 41a, inside which one ends of a total of three power supply terminals PT (see FIG. 2) are arranged, and a second terminal hole 41b, inside which one ends of a total of five sensor terminals ST (see FIG. 2) are arranged. A first cap CP1 and a second cap CP2 are attached to the first terminal hole 41a and the second terminal hole 41b, respectively, to cover the power supply terminals PT and the sensor terminals ST.

[0048] 1 and 3, a cylindrical wall portion 46 having a larger diameter than the insertion cylindrical portion 42 is provided radially outward of the insertion cylindrical portion 42. Specifically, the cylindrical wall portion 46 is disposed on the outer periphery of the partition wall portion 41.

[0049] The cylindrical wall portion 46 is disposed coaxially with the insertion cylindrical portion 42 and extends in the axial direction of the rotation shaft 32. A total of three driven object fixing portions 47 are integrally formed on the cylindrical wall portion 46. Metal cylindrical collars CL are provided on these driven object fixing portions 47. This allows the motor device 10 to be securely fixed to the driven object without damaging the resin driven object fixing portions 47.

[0050] The driven object fixing portions 47 are arranged at predetermined intervals around the circumferential direction of the cylindrical wall portion 46, and when the bracket 40 is viewed from the other axial side (the case 20 side), they protrude radially outward from the cylindrical wall portion 46. A fixing bolt for fixing the motor device 10 to the driven object is inserted into a collar CL held by the driven object fixing portion 47.

[0051] Furthermore, a connector connection portion CN is integrally provided on the radially outer side of the cylindrical wall portion 46. The connector connection portion CN is formed in a substantially rectangular parallelepiped shape, and a connector member on the vehicle side can be connected from the other axial side of the cylindrical wall portion 46 (the lower side in FIG. 3).

[0052] Furthermore, a total of three case fixing portions 48 are integrally formed on the cylindrical wall portion 46. These case fixing portions 48 are portions to which the flange portion 24 of the case 20 is fixed, and each holds a cylindrical internally threaded member IT (see FIG. 3) made of steel. Then, a first externally threaded member S1 for fixing the case 20 to the bracket 40 is screwed into each of these internally threaded members IT.

[0053] A total of three case fixing portions 48 are arranged at predetermined intervals in the circumferential direction of the cylindrical wall portion 46, and the case fixing portions 48 are provided between adjacent driven object fixing portions 47. Furthermore, each case fixing portion 48 protrudes radially outward from the cylindrical wall portion 46 when the bracket 40 is viewed from the other axial side (the case 20 side).

[0054] Furthermore, as shown in FIG. 3, a fitting cylindrical portion 49 is integrally provided on the other axial side (case 20 side) of bracket 40 and between insertion cylindrical portion 42 and cylindrical wall portion 46 in the radial direction of bracket 40.

[0055] The fitting cylindrical portion 49 is a portion that is fitted into the opening 22 of the case 20, and an annular seal SL made of an elastic material such as rubber is attached to the radial outside of the fitting cylindrical portion 49. The annular seal SL provides a seal between the bracket 40 and the case 20.

[0056] <Sensor board> 3, the sensor board 50 fixed to the bracket 40 is disposed between the second bearing BR2 and the annular magnet 62 of the magnet unit 60 in the axial direction of the rotating shaft 32. A total of three Hall elements 51 (only one is shown in the figure) are mounted on the sensor board 50. Specifically, the three Hall elements 51 are provided corresponding to the U phase, V phase, and W phase, and are disposed around a through hole 52 provided in the center of the sensor board 50.

[0057] Here, the three Hall elements 51 detect changes in the magnetic poles of the annular magnet 62 as the rotating shaft 32 rotates. In other words, the Hall elements 51 detect the rotational state of the annular magnet 62. One ends of five sensor terminals ST are electrically connected to the sensor board 50. The other ends of the five sensor terminals ST are exposed to the inside of a connector connection portion CN to which a connector member on the vehicle side is connected (see FIGS. 2 and 3).

[0058] <Magnet unit> 4 and 6 to 8, the magnet unit 60 includes a holder member 61 and an annular magnet 62. The holder member 61 is made of, for example, free-cutting brass "C3604" and is machined into a cylindrical shape with a flange and a step. In other words, the holder member 61 is a machined product, and its hardness (Vickers hardness) is approximately "131 Hv."

[0059] That is, the rotating shaft 32 into which the magnet unit 60 is fitted has a hardness (approximately 700 Hv) higher than the hardness of the holder member 61 (approximately 131 Hv).

[0060] The holder member 61 includes a cylindrical main body 61a. The cylindrical main body 61a is provided so as to protrude from the other axial side (the right side in FIG. 8) of the annular magnet 62, and extends in the axial direction of the rotating shaft 32. The cylindrical main body 61a is fixed by press-fitting into the columnar portion 33a of the medium diameter portion 33, and its axial length is LG1.

[0061] The inner diameter D3 of the cylindrical main body 61a is slightly larger than the outer diameter of the columnar portion 33a. This allows the cylindrical main body 61a to be press-fitted into the columnar portion 33a with a predetermined pressing force F (see FIG. 11). The axial length LG1 of the cylindrical main body 61a is smaller than the length L3 of the columnar portion 33a (LG1 <L3)。

[0062] Furthermore, an attachment guide tapered surface TP is provided at the end of the cylindrical main body 61a on the other axial side (the right side in FIG. 8) to guide the insertion of the rotating shaft 32. Specifically, the attachment guide tapered surface TP is provided on the radially inner side of the cylindrical main body 61a, and is formed so that the opening area of ​​the cylindrical main body 61a gradually increases toward the other axial side of the cylindrical main body 61a. The attachment guide tapered surface TP has an acute angle with respect to the axis C of the rotating shaft 32 (see FIG. 9) of α degrees, which is approximately 20 degrees but not more than 45 degrees.

[0063] This allows the axis C of the rotating shaft 32 inserted into the cylindrical main body 61a to be easily aligned (centered) with the center of the cylindrical main body 61a. In other words, the mounting guide tapered surface TP has the function of guiding the mounting of the columnar portion 33a into the cylindrical main body 61a.

[0064] Here, if the angle of the mounting guide tapered surface TP on the acute side relative to the axis C of the rotating shaft 32 is increased (for example, greater than 45 degrees), the rotating shaft 32 becomes more likely to get caught on the mounting guide tapered surface TP, which reduces the ease of assembly of the motor device 10. Therefore, in this embodiment, the angle of the mounting guide tapered surface TP is set to α degrees (approximately 20 degrees), making it less likely that the rotating shaft 32 will get caught on the cylindrical main body 61a, allowing them to be quickly centered relative to each other (improving assembly ease).

[0065] The holder member 61 corresponds to the fixed part in this invention, and the cylindrical main body portion 61a corresponds to the press-fit cylindrical portion in this invention.

[0066] The holder member 61 also includes a gap forming cylindrical portion 61b. Specifically, the gap forming cylindrical portion 61b is provided alongside one axial side (the left side in FIG. 8) of the cylindrical main body portion 61a and overlaps with a portion of the tapered portion 33b and the entire arc-shaped connecting portion 33c in the radial direction of the rotating shaft 32. The inner diameter dimension D4 of the gap forming cylindrical portion 61b is larger than the inner diameter dimension D3 of the cylindrical main body portion 61a (D4>D3). Therefore, an annular gap SP is formed between the gap forming cylindrical portion 61b and the tapered portion 33b and the arc-shaped connecting portion 33c in the radial direction of the rotating shaft 32.

[0067] Here, by providing an annular gap SP radially inward of the gap forming cylindrical portion 61b, even if burrs (shavings) are generated when the rotating shaft 32 is press-fitted into the holder member 61, the burrs are small and can be retained in the annular gap SP. Furthermore, by providing the annular gap SP, strain is prevented from being transmitted to the flange portion 61c that holds the annular magnet 62 when the rotating shaft 32 is press-fitted into the cylindrical main body portion 61a. Therefore, no strain is generated in the annular magnet 62.

[0068] A flange portion 61c is integrally provided on one axial side (the left side in FIG. 8) and radially outward of the gap forming cylindrical portion 61b. The flange portion 61c is formed in a substantially circular plate shape and protrudes radially outward from the gap forming cylindrical portion 61b. An outer peripheral tip portion 61d of the flange portion 61c fits into an inner peripheral recess 62a of the annular magnet 62. The holder member 61 and the annular magnet 62 are integrated during injection molding of the annular magnet 62.

[0069] Specifically, the annular magnet 62 is a so-called plastic magnet made by mixing plastic with magnet raw material, and is formed into a substantially annular shape by injection molding using a mold. In this way, the annular magnet 62 is an injection molded product, and as shown in Fig. 6, a pair of gate marks GT are formed on the annular magnet 62.

[0070] In this way, the holder member 61 holds the annular magnet 62 used to detect the rotation state of the rotary shaft 32. The annular magnet 62 corresponds to the sensor magnet in the present invention.

[0071] <Assembly Instructions> Next, the procedure for attaching (assembling) the magnet unit 60 to the rotary shaft 32 will be described in detail with reference to the drawings.

[0072] FIG. 9 is an assembly explanatory diagram showing the "parts setting process," FIG. 10 is an assembly explanatory diagram showing the "rotation axis moving process," and FIG. 11 is an assembly explanatory diagram showing the "press-fitting process."

[0073] <Parts assembly process> First, as shown in FIG. 9, the rotating shaft 32 and the magnet unit 60 are prepared, each manufactured in a separate manufacturing process.

[0074] Next, the rotating shaft 32 is set in the conveying device CD. Specifically, the conveying device CD has a pair of shaft holding members SN that hold the rotating shaft 32 from both axial sides, as shown by arrow M1, and these shaft holding members SN are capable of moving in the axial direction of the rotating shaft 32 while holding the rotating shaft 32. In other words, the conveying device CD has the function of conveying the rotating shaft 32 in its axial direction.

[0075] The magnet unit 60 is set in the gripping device GD. Specifically, the gripping device GD has a pair of unit holding members MN that hold the magnet unit 60 from the radially outer side in a direction perpendicular to the axial direction of the rotating shaft 32, as shown by arrow M2. Note that the pair of unit holding members MN have the function of positioning the magnet unit 60 on the axis C of the rotating shaft 32 in a state in which they hold the magnet unit 60. Note that the pair of unit holding members MN are unable to move in the axial direction of the rotating shaft 32.

[0076] Then, as shown in Fig. 9, with the rotating shaft 32 set in the conveying device CD and the magnet unit 60 set in the gripping device GD, that is, in the standby state, the distance between the end on the other axial side of the rotating shaft 32 and the end on the other axial side of the gripping device GD is the set distance DS1. Therefore, each component (rotating shaft 32 and magnet unit 60) can be easily set individually.

[0077] As a result, the [component setting process] is completed. Then, the conveying device CD is driven to set the feed speed to V1 (10 mm / s), and the rotating shaft 32 is moved toward the magnet unit 60.

[0078] <Rotating shaft movement process> Here, as shown in Fig. 9, until the rotating shaft 32 faces the magnet unit 60 and the cylindrical portion 33a of the middle diameter portion 33 is press-fitted into the cylindrical main body portion 61a of the holder member 61, the rotating shaft 32 is moved at a relatively fast feed speed V1 (10 mm / s). Next, as shown in Fig. 10, when the distance between the end on the other axial side of the rotating shaft 32 and the end on the other axial side of the gripping device GD becomes the pre-press-fitting distance DS2 (DS2 < DS1), the conveying device CD automatically sets the feed speed to V2 (1 mm / s).

[0079] Specifically, as shown in Fig. 10, when the cylindrical main body portion 61a is arranged closer to the middle diameter portion 33 of the small diameter portion 32b of the rotating shaft 32, the feed speed is reduced to the feed speed V2 which is 1 / 10 of the feed speed V1. As a result, the rotating shaft 32 can be quickly moved to the stage immediately before press-fitting into the cylindrical main body portion 61a.

[0080] As a result, the [rotating shaft movement process] is completed. Then, it proceeds to the [press-fitting process] in Fig. 11.

[0081] <Press-fitting process> As shown in FIG. 11, the conveying device CD is kept constant at a feed speed V2 (1 mm / s), and is driven to generate a relatively large pressing force F so that the cylindrical portion 33a can be press-fitted into the cylindrical main body portion 61a. Then, the cylindrical main body portion 61a is fitted onto the cylindrical portion 33a of the middle diameter portion 33 via the tapered portion 33b and the arcuate connecting portion 33c (see FIG. 8) of the middle diameter portion 33. At this time, the middle diameter portion 33 is guided by the mounting guide tapered surface TP (see FIG. 8) of the cylindrical main body portion 61a and smoothly fitted onto the cylindrical main body portion 61a.

[0082] After that, when the distance between the end on the other side in the axial direction of the rotary shaft 32 and the end on the other side in the axial direction of the gripping device GD becomes the press-fitting completion distance DS3 (DS3 < DS2), the conveying device CD is automatically stopped.

[0083] Therefore, the magnet unit 60 is positioned at a specified position in the axial direction with respect to the rotary shaft 32. Thereby, the [press-fitting process] is completed, and the fixing operation of the magnet unit 60 with respect to the rotary shaft 32 ends.

[0084] <Comparison and verification of burr generation> FIG. 12 is a diagram for explaining the assembled state of the present embodiment, FIG. 13 is a diagram corresponding to FIG. 8 showing a comparative example, and FIG. 14 is a diagram for explaining the assembled state of the comparative example. The upper enlarged photographs in FIGS. 12 and 14 show the press-fitting portion (fitting portion) between the rotary shaft and the magnet unit as viewed from one side in the axial direction.

[0085] As shown in the upper enlarged photograph in FIG. 12, in the rotary shaft 32 and the magnet unit 60 according to the present embodiment, so-called "burrs (shavings)" were not found. That is, it was confirmed that the assembled state of the present embodiment is good and that subsequent deburring work is unnecessary.

[0086] This is because, as shown in the graph at the bottom of Fig. 12, from the "start of press-fitting" of the medium diameter portion 33 into the cylindrical main body portion 61a (see Fig. 8), the load [kN] increases relatively gradually as indicated by the dashed arrow as the stroke [mm] of the rotating shaft 32 relative to the magnet unit 60 increases. Specifically, the arc-shaped connecting portion 33c (see Fig. 8) provided by grinding on the rotating shaft 32 acts to deform the cylindrical main body portion 61a so that its diameter gradually expands without cutting off the inner peripheral portion of the cylindrical main body portion 61a.

[0087] Even if some burrs are generated, the burrs are small and remain in the annular gap SP between the gap forming cylindrical portion 61b of the holder member 61 and the medium diameter portion 33 of the rotating shaft 32. Therefore, there is no need for subsequent deburring work.

[0088] As a comparative example, a structure similar to the conventional fixing structure was prepared, and the occurrence of burrs was observed. As shown in Fig. 13, the rotating shaft SH (Vickers hardness: 700 Hv) of the comparative example has a tapered portion TR and a cylindrical portion CR, but there is no arc-shaped connection between the tapered portion TR and the cylindrical portion CR in the axial direction of the rotating shaft SH; instead, there is an edge ED. Furthermore, a circular C-chamfered portion CC with a β-degree angle (45 degrees) is provided on the other axial side (right side in Fig. 13) of the cylindrical main body portion CM (Vickers hardness: 131 Hv) of the magnet unit MU.

[0089] As shown in the enlarged photograph at the top of Figure 14, in the comparative example, a number of relatively large burrs that were visible to the naked eye were generated, which indicated that the comparative example required subsequent deburring work.

[0090] This is because the edge ED of the rotating shaft SH abuts against the inner periphery of the cylindrical main body CM with a strong force, and the load [kN] increases rapidly as the stroke [mm] of the rotating shaft SH relative to the magnet unit MU increases, as shown by the dashed arrow, as shown in the lower graph of Figure 14. This causes the inner periphery of the cylindrical main body CM to be scraped by the edge ED, resulting in the generation of several relatively large burrs.

[0091] Furthermore, the annular C-chamfered portion CC with an angle of β degrees (45 degrees) provided on the other axial side of the cylindrical main body CM has a poorer centering function for the rotation axis SH than the tapered surface TP for mounting guide (α degrees = approximately 20 degrees) of this embodiment. Therefore, the edge ED gets caught on the C-chamfered portion CC, which also causes burrs.

[0092] <Modification> The magnet unit 60 may be fixed to the rotary shaft 32 in a modified structure as shown in FIG.

[0093] Fig. 15 is a diagram corresponding to Fig. 8 showing a modified example. Only the parts different from Fig. 8 will be explained below. Note that parts having the same functions as those in Fig. 8 are given the same symbols, and detailed explanations thereof will be omitted.

[0094] As shown in FIG. 15, in the modified example, the length dimension L4 of the tapered portion 33b forming the medium diameter portion 33 is set to be longer than the length dimension L2 of the tapered portion 33b shown in FIG. 8 (L4>L2), and the length dimension L5 of the cylindrical portion 33a is set to be shorter than the length dimension L3 of the cylindrical portion 33a shown in FIG. 8 (L5 <L3)。

[0095] In addition, the axial length LG2 of the cylindrical main body portion 61a forming the holder member 61 is longer than the axial length LG1 of the cylindrical main body portion 61a shown in Figure 8 (LG2>LG1), and the cylindrical main body portion 61a is opposed to a part of the cylindrical portion 33a and the arc-shaped connecting portion 33c in the radial direction of the rotation shaft 32.

[0096] As a result, as shown by the dashed circle (enlarged view) in Fig. 15, a minute gap SS is formed between the cylindrical main body portion 61a and the arc-shaped connecting portion 33c in the radial direction of the rotating shaft 32. Note that the fitting portion MP between the cylindrical main body portion 61a and the columnar portion 33a is made equivalent to that in Fig. 8 by increasing the axial length LG2 of the cylindrical main body portion 61a. In other words, the fixing strength of the magnet unit 60 to the rotating shaft 32 is the same in both the embodiment shown in Fig. 8 and the modified example shown in Fig. 15.

[0097] 15, when the magnet unit 60 is fixed at a predetermined position on the rotary shaft 32, a minute gap SS is formed between the cylindrical main body 61a and the arc-shaped connecting portion 33c. As a result, even if the inner periphery of the cylindrical main body 61a is scraped and a burr is generated, the generated burr does not need to be cut off from the inner periphery of the cylindrical main body 61a. In other words, the generated burr can remain connected to the inner periphery of the cylindrical main body 61a.

[0098] Therefore, compared to the embodiment shown in FIG. 8, it is possible to more reliably cause any burrs that have occurred to remain in the annular gap SP between the gap forming cylindrical portion 61b and the medium diameter portion 33.

[0099] As described above in detail, according to this embodiment, the rotating shaft 32 comprises the cylindrical portion 33a having a constant outer diameter in the axial direction of the rotating shaft 32, the tapered portion 33b provided on one axial side of the cylindrical portion 33a and having an outer diameter that decreases with increasing distance from the cylindrical portion 33a, and the arc-shaped connecting portion 33c provided between the cylindrical portion 33a and the tapered portion 33b, and the arc-shaped connecting portion 33c connects the outer peripheral surface of the cylindrical portion 33a and the outer peripheral surface of the tapered portion 33b with an arcuate surface when the rotating shaft 32 is viewed from the outside in the radial direction. The holder member 61 comprises a cylindrical main body portion 61a into which the cylindrical portion 33a is press-fitted, and a gap-forming cylindrical portion 61b provided on one axial side of the cylindrical main body portion 61a and forming a gap SP between it and the arc-shaped connecting portion 33c in the radial direction of the rotating shaft 32.

[0100] As a result, when the columnar portion 33a is press-fitted into the cylindrical main body portion 61a, the action of the arc-shaped connecting portion 33c allows the load to be gradually increased as the stroke of the rotating shaft 32 relative to the magnet unit 60 increases. Therefore, the generation of burrs (shavings) can be suppressed, making subsequent deburring unnecessary and simplifying the manufacturing process. Even if burrs are generated, they can be kept in the gap SP between the gap forming cylindrical portion 61b and the medium diameter portion 33, making subsequent deburring unnecessary.

[0101] Furthermore, according to this embodiment, the rotating shaft 32 has a hardness higher than that of the holder member 61, so even if a burr occurs, the rotating shaft 32 is not scraped, but the holder member 61 is scraped, thereby minimizing disruption of the rotational balance of the rotating shaft 32. Moreover, even if a burr occurs, the holder member 61 is scraped, so the burr can be reliably guided into the gap SP.

[0102] Furthermore, according to this embodiment, the axial end of the cylindrical main body 61a is provided with an attachment guide tapered surface TP that guides the attachment of the columnar portion 33a to the cylindrical main body 61a, making it possible to smoothly attach the columnar portion 33a to the cylindrical main body 61a, thereby further suppressing the occurrence of burrs.

[0103] Furthermore, according to this embodiment, the angle of the mounting guide tapered surface TP on the acute side relative to the axis C of the rotating shaft 32 is α degrees, which is approximately 20 degrees and is not more than 45 degrees, so the axis C of the rotating shaft 32 can be easily aligned (centered) with the center of the cylindrical main body 61a without scraping each other. Therefore, the two can be assembled without getting caught, which also makes it possible to further suppress the occurrence of burrs.

[0104] Furthermore, according to this embodiment, the fixed part fixed to the rotating shaft 32 is the holder member 61 that holds the annular magnet 62 used to detect the rotation state of the rotating shaft 32, and it is possible to prevent burrs from being generated on the holder member 61. This ensures sufficient fixing strength of the holder member 61 (annular magnet 62) to the rotating shaft 32, and also makes it possible to precisely align the axes of the two. This makes it possible to improve sensing accuracy.

[0105] Furthermore, according to this embodiment, the need for a post-process, deburring, can be eliminated, thereby reducing the energy required to manufacture the motor device 10. This makes it possible to achieve the Sustainable Development Goals (SDGs) established by the United Nations, particularly Goal 7 (Ensure access to affordable, reliable, sustainable and modern energy for all) and Goal 13 (Take urgent action to combat climate change and its impacts).

[0106] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, in the above-described embodiment, the motor device 10 is shown as a drive source for an electric brake device mounted on a vehicle such as an automobile, but the present invention is not limited to this, and can also be applied to drive sources for other in-vehicle devices (such as a drive source for an electric power steering).

[0107] Furthermore, the material, shape, size, number, installation location, etc. of each component in the above-described embodiments are arbitrary as long as they can achieve the present invention, and are not limited to the above-described embodiments. [Explanation of symbols]

[0108] 10: motor device, 20: case, 21: cylindrical portion, 22: opening, 23: bottom wall portion, 24: flange portion, 25: stator, 26: stator core, 26a: core body, 26b: teeth, 27: insulator, 28: coil, 29: busbar unit, 29a: holding member, 30: conductive member, 31: rotor, 32: rotating shaft, 32a: large diameter portion, 32b: small diameter portion, 32c: bearing support portion, 32d: pinion gear portion, 33: medium diameter portion, 33a: cylindrical portion (straight portion), 33b: tapered portion, 33c: arc-shaped connection part (connection part), 34: rotor body, 35: rotor core, 36: magnet, 37: magnet cover, 38: magnet protection member, 40: bracket, 41: partition wall part, 41a: first terminal hole, 41b: second terminal hole, 42: insertion cylinder part, 43: bearing holder, 43a: insertion hole, 44: annular fixing plate, 46: cylindrical wall part, 47: driven object fixing part, 48: case fixing part, 49: fitting cylinder part, 50: sensor board, 51: hall element, 52: through hole, 60: magnet unit, 61: holder member (fixing part ), 61a: cylindrical main body portion (press-fit cylindrical portion), 61b: gap forming cylindrical portion, 61c: flange portion, 61d: outer peripheral tip portion, 62: annular magnet (sensor magnet), 62a: inner peripheral recess, AG: air gap, BR1: first bearing, BR2: second bearing, C: axis line, CC: C chamfered portion (comparison example), CD: conveying device, CL: collar, CM: cylindrical main body portion (comparison example), CN: connector connecting portion, CP1: first cap, CP2: second cap, CR: cylindrical portion (comparison example), DS1: set distance, DS2: distance just before press-fit, D S3: press-fit completion distance, ED: edge (comparison example), F: pressing force, GD: gripping device, GT: gate mark, H1: first insertion hole, H2: second insertion hole, IT: female thread member, MN: unit holding member, MP: mating portion, MU: magnet unit (comparison example), PT: power terminal, S1: first male thread member, S2: second male thread member, SH: rotating shaft (comparison example), SL: annular seal, SN: shaft holding member, SP: gap, SS: minute gap, ST: sensor terminal, TP: tapered surface for installation guide, TR: tapered portion (comparison example)

Claims

1. A rotation axis; a fixed component fixed to the rotating shaft; A motor device having The rotation axis is a straight portion having a constant outer diameter in an axial direction of the rotary shaft; a tapered portion provided on one axial side of the straight portion, the tapered portion having an outer diameter that gradually decreases with increasing distance from the straight portion; a connecting portion provided between the straight portion and the tapered portion; Equipped with The connection portion is When the rotary shaft is viewed from the outside in the radial direction, an outer circumferential surface of the straight portion and an outer circumferential surface of the tapered portion are connected by an arcuate surface, The fixing part is a press-fitting cylindrical portion into which the straight portion is press-fitted; a gap forming cylindrical portion provided on one axial side of the press-fitting cylindrical portion and forming a gap between the press-fitting cylindrical portion and the connecting portion in the radial direction of the rotation shaft; having Motor device.

2. The rotating shaft has a hardness higher than that of the fixed component. The motor device according to claim 1 .

3. 2. The motor device according to claim 1, an axial end of the press-fitting cylindrical portion is provided with an attachment guide tapered surface that guides attachment of the straight portion to the press-fitting cylindrical portion; Motor device.

4. the angle of the mounting guide tapered surface relative to the axis of the rotation shaft on the acute angle side is 45 degrees or less; The motor device according to claim 3 .

5. the fixed component is a holder member that holds a sensor magnet used to detect the rotation state of the rotary shaft; The motor device according to any one of claims 1 to 4.

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