Worm gears and rotating gears

Abstract

To realize noise reduction.SOLUTION: A resin worm formed by injection molding includes a portion having teeth, one end part, and the other end part having an apex. The portion includes a cavity extending in a rotary shaft direction. An outer peripheral side surface of the other end part in a circumferential direction has one or more annular marks.SELECTED DRAWING: Figure 8

Description

Technical Field

[0004] ,

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[0001] The present invention relates to a worm and a rotating device.

Background Art

[0002] In a gearbox with a motor equipped with a worm, etc., a technique for improving the accuracy of the worm is known for noise reduction, etc. For example, a technique is known in which the teeth at both ends of the worm have inclined surfaces whose outer shape becomes smaller toward the ends. Also known is a worm having a shaft hole press-fitted from the base end portion to the motor shaft, and having a positioning contact portion having an air hole communicating with the shaft hole at the tip end portion of the shaft hole, and the bottom portion of the air hole being located on the base end portion side of the shaft hole rather than the tip end position of the motor shaft.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

[0007] According to one embodiment, the precision of the worm can be improved. According to another embodiment, the noise reduction of the rotating device can be achieved. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a plan view showing an example of a rotating device in an embodiment. [Figure 2] Figure 2 is a side view showing an example of a rotating device in an embodiment. [Figure 3] Figure 3 is a bottom view showing an example of a rotating device in an embodiment. [Figure 4] Figure 4 is a perspective view of the rotating device in the embodiment with the first housing removed. [Figure 5] Figure 5 is a plan view of the rotating device in the embodiment with the first housing removed. [Figure 6] Figure 6 is a perspective view showing an example of the first housing in the embodiment. [Figure 7] Figure 7 is a perspective view showing an example of the second housing in the embodiment. [Figure 8] Figure 8 is a top view showing an example of the positional relationship between the hassba gear and the worm in an embodiment. [Figure 9] Figure 9 is a perspective view showing an example of the positional relationship between the hassba gear and the worm in an embodiment. [Figure 10] Figure 10 is an enlarged cross-sectional view showing an example of a rotating device in an embodiment. [Figure 11] Figure 11 is a cross-sectional view showing an example of a worm in an embodiment. [Figure 12]FIG. 12 is a cross-sectional view for explaining an example of a mold in an embodiment. [Figure 13] FIG. 13 is a cross-sectional view showing an example of a method for molding a worm in an embodiment. [Figure 14] FIG. 14 is an enlarged cross-sectional view for explaining an example of a method for molding a worm in an embodiment. [Figure 15] FIG. 15 is a perspective view showing an example of the positional relationship between a spur gear and a worm in a first modification. [Figure 16] FIG. 16 is a cross-sectional view showing an example of a worm in a first modification. [Figure 17] FIG. 17 is a cross-sectional view for explaining an example of a mold in a first modification. [Figure 18] FIG. 18 is a cross-sectional view showing an example of a method for molding a worm in a first modification. [Figure 19] FIG. 19 is an enlarged cross-sectional view for explaining an example of a method for molding a worm in a first modification.

BEST MODE FOR CARRYING OUT THE INVENTION

[0009] [[ID=...]] Hereinafter, embodiments of the worm disclosed in the present application will be described in detail based on the drawings. Note that the dimensional relationships between elements in the drawings, the ratios of the elements, etc. may differ from reality. There may also be portions where the dimensional relationships and ratios between the drawings are different from each other. In each drawing, for the sake of easy understanding of the explanation, in some cases, a coordinate system is illustrated in which the direction in which the rotation axis 31 of the motor 3 to be described later extends, that is, the longitudinal axis direction of the worm 10, is the X-axis direction, and the direction in which the output axis 51 to be described later extends, which is orthogonal to the rotation axis 31, is the Z-axis direction.

[0010] [Embodiment] FIG. 1 is a plan view showing an example of a rotating device in an embodiment, FIG. 2 is a side view showing an example of the rotating device in the embodiment, and FIG. 3 is a bottom view showing an example of the rotating device in the embodiment. Further, FIG. 4 is a perspective view of the rotating device in the embodiment with the first housing removed, FIG. 5 is a plan view of the rotating device in the embodiment with the first housing removed, FIG. 6 is a perspective view showing an example of the first housing in the embodiment, and FIG. 7 is a perspective view showing an example of the second housing in the embodiment.

[0011] The rotating device 1 according to the embodiment can be suitably used, for example, as an actuator used in an air conditioning system for a vehicle or the like, and can control the rotation operation of a louver for controlling the air volume or the like.

[0012] As shown in FIGS. 1 to 3, the rotating device 1 includes, inside, a motor 3 shown in FIGS. 4 and 5, a plurality of gears (hereinafter referred to as a gear group) 6 that transmit power from the motor 3, and a sensor 7 that detects the rotation angle of an output gear 5 included in the gear group 6.

[0013] The gear group 6 includes a worm 10 attached to the rotation shaft 31 (see FIG. 10) of the motor 3, a first transmission gear 61, a second transmission gear 62, and an output gear 5. As shown in FIGS. 8 and 9, the first transmission gear 61 is located on the positive side in the Y-axis direction with respect to the worm 10. FIG. 8 is a top view showing an example of the positional relationship between the spur gear and the worm in the embodiment. FIG. 9 is a perspective view showing an example of the positional relationship between the spur gear and the worm in the embodiment. Note that the first transmission gear 61 is an example of a gear that meshes with the worm.

[0014] As shown in Figures 8 to 10, the worm 10 comprises a cylindrical portion 11, one end 16 located in the positive direction relative to the cylindrical portion 11 in the X-axis direction, and the other end 13 located in the negative direction relative to the cylindrical portion 11. Figure 10 is an enlarged cross-sectional view showing an example of a rotating device in an embodiment. Figure 10 shows a cross-section cut along line AA in Figure 2. Note that the negative direction in the X-axis direction is one example in the direction of the long axis, and the cylindrical portion 11 is an example of a part having a gear.

[0015] The worm 10 is made of resin and is formed, for example, by injection molding. In this embodiment, the teeth 12 are formed spirally on the outer circumference of the cylindrical portion 11, as shown in Figures 8 and 9.

[0016] Returning to Figure 4, the rotation of the worm 10 is transmitted to the helical gear 61a of the first transmission gear 61, and then to the second transmission gear 62 via a gear 61b, which is coaxial with the helical gear 61a and has a smaller diameter than the helical gear 61a. The helical gear 61a is, for example, a helical gear that meshes with the teeth 12 of the worm 10. The rotation of the second transmission gear 62 is then transmitted to the output gear 5. The output gear 5 is also provided with an output shaft 51 (Figure 3). The rotation axes of the first transmission gear 61 and the second transmission gear 62 extend in the direction of the output shaft 51 (Z-axis direction) and extend in a direction intersecting the rotation axis direction of the worm 10 (X-axis direction).

[0017] In this way, the rotation of the motor 3 is reduced by a predetermined reduction ratio and output to the outside from the output shaft 51. The rotation angle of this output gear 5 is then detected by the sensor 7. The information of the rotation angle of the output gear 5 detected by the sensor 7 is transmitted to the outside, for example, via the terminal group 4 shown in Figures 4 and 5. Note that the sensor 7 may detect the rotation speed of the output gear 5 instead of the rotation angle, or it may detect both the rotation angle and the rotation speed. In this embodiment, a DC motor with a commutator and brushes is used as the motor 3, but a brushless motor or a stepping motor may also be used. If a brushless motor or a stepping motor is used, the sensor 7 may not be necessary for the rotating device 1.

[0018] As shown in Figure 2, the housing 2 comprises a first housing 21 and a second housing 22 facing each other in the Z-axis direction. That is, the housing 2 is constructed by connecting a first housing 21 (Figure 6) having an opening 214 and a second housing 22 (Figure 7) having an opening 226, with the openings 214 and 226 facing each other.

[0019] As shown in Figures 2 and 6, the first housing 21 has a first surface 210 which forms the top surface of the housing 2, and a first side wall 211 provided on the outer periphery of the first surface 210. The opening 214 is surrounded by the first side wall 211. On the other hand, as shown in Figures 3 and 7, the second housing 22 has a second surface 220 which forms the bottom surface of the housing 2, and a second side wall 222 provided on the outer periphery of the second surface 220. The opening 226 is surrounded by the second side wall 222. The housing 2 is formed from an elastic or deformable resin material such as polypropylene, polyethylene terephthalate, ABS, or polycarbonate.

[0020] Furthermore, as shown in Figure 6, the first housing 21 has a plurality of engaging portions 212 that extend toward the second housing 22, integrally formed on the outer circumference of the first side wall portion 211. These engaging portions 212 are provided with recesses (hereinafter referred to as engaging recesses) 215. On the other hand, as shown in Figure 7, the second housing 22 has a plurality of protrusions (hereinafter referred to as engaging protrusions) 224 integrally formed on the second side wall portion 222, which serve as engaged portions corresponding to the plurality of engaging portions 212 of the first housing 21. These engaging protrusions 224 engage with the engaging recesses 215 of the engaging portions 212.

[0021] In this way, the housing 2 is formed by joining the first housing 21 and the second housing 22 together (see Figure 2). That is, by engaging the engaging projection 224 of the second housing 22 with the engaging recess 215 of the engaging portion 212 of the first housing 21, the first housing 21 and the second housing 22 are integrated, forming the housing 2 that houses the motor 3 and gear group 6 mentioned above. Note that in Figure 2, the engaging projection 224 of the second housing 22 is hidden by the engaging portion 212 of the first housing 21 and is not visible.

[0022] In this embodiment, the first housing 21 is provided with an engaging portion 212 and the second housing 22 is provided with an engaging projection 224. However, the second housing 22 may be provided with an engaging portion 212 and the first housing 21 may be provided with an engaging projection 224.

[0023] Furthermore, as shown in Figure 6, the first housing 21 is provided with a plurality of protrusions 91 for positioning, and as shown in Figure 7, the second housing 22 is provided with a plurality of holes (hereinafter referred to as fitting holes) 92 that correspond to the plurality of protrusions 91 of the first housing 21. When the first housing 21 and the second housing 22 are joined together by butting them, the protrusions 91 fit into the fitting holes 92.

[0024] Furthermore, as shown in Figures 6 and 7, both ends of one side of the first housing 21 and the second housing 22 have outwardly protruding pieces (hereinafter referred to as connecting pieces) 93. The connecting pieces 93 are provided with holes (hereinafter referred to as connecting holes) 94 through which a fastening device (not shown) is inserted as a predetermined fixing member. The joined first housing 21 and the second housing 22 are firmly connected by the predetermined fastening device via the four connecting holes 94, forming a single housing 2.

[0025] In the configuration of the housing 2 described above, in this embodiment, a projection 28 is provided at the corner of the first side wall portion 211 that forms the outer periphery of the first housing 21, and a second through hole 282 is provided at the corner of the second housing 22. That is, the first housing 21 has a cylindrical projection 28 that protrudes from the first surface portion 210 and has a first through hole 281 through which fasteners such as bolts and screws can be inserted. The second housing 22 is provided with a second through hole 282 into which the projection 28 fits.

[0026] Multiple protrusions 28 are provided, and accordingly, multiple second through holes 282 are also provided. Each of the multiple protrusions 28 is provided at one of the four corners of the first housing 21, and each of the multiple second through holes 282 is provided at one of the four corners of the second housing 22. In this embodiment, the first surface 210 of the first housing 21 and the second surface 220 of the second housing 22 have a substantially rectangular shape in plan view, and the protrusions 28 and second through holes 282 are provided at the four corners of each.

[0027] The configuration of the motor 3 will be briefly explained. As shown in Figures 4, 5, and 10, the motor 3 in this embodiment comprises a rotating shaft 31 and a frame 30 that houses the functional unit. Here, the functional unit refers to a collection of components necessary for driving the motor 3, excluding the rotating shaft 31, such as a stator and rotor having magnets and coils. In other words, the motor 3 comprises the frame 30, the rotating shaft 31 connected to the worm 10, and the functional unit.

[0028] As shown in Figures 4 and 5, the frame 30 comprises a cylindrical body 32 extending in the direction of the rotation axis of the motor 3, and two ends (a first end 34 and a second end 35) in the direction of the rotation axis. As shown in Figure 8, the first end 34 is one end on the worm 10 side, and the second end 35 is the other end on the opposite side from the worm 10.

[0029] Furthermore, as shown in Figure 10, the first end 34 of the frame 30 includes a first outer surface 342 on the negative X-axis side and a first bearing portion 341 that rotatably supports the portion of the rotating shaft 31 on the worm 10 side via a first bearing 349. A worm 10 having teeth 12 that mesh with the first transmission gear 61 is attached to the portion of the rotating shaft 31 that protrudes from the first end 34.

[0030] Figures 8 and 11 are a front view and a cross-sectional view showing an example of a worm in an embodiment. As shown in Figure 8, the worm 10 comprises a cylindrical portion 11 which is a part having an outer peripheral surface, a portion 16 on the motor 3 side of this portion (hereinafter referred to as one end), and a portion 13 on the opposite side of the motor 3 from this portion (hereinafter referred to as the other end).

[0031] The other end 13 comprises a top portion 13a (13a1 and 13a2), which will be described later, a plurality of inclined surfaces (outer surfaces) 13b arranged to surround the top portion 13a, a plurality of vertical surfaces (outer surfaces) 13c, a plurality of outer peripheral surfaces (outer surfaces) 13d, an outer peripheral surface 13e, a vertical surface (outer surface) 13f, and a vertical surface (outer surface) 13g. Of these, the plurality of vertical surfaces 13c are each arranged between the plurality of inclined surfaces 13b in the circumferential direction. The plurality of outer peripheral surfaces 13d extend in the direction of the rotation axis of the worm 10 (sometimes referred to as the axis direction), and are located between the plurality of inclined surfaces 13b and the plurality of vertical surfaces 13c in the direction of the rotation axis of the worm 10. In this embodiment, the inclined surfaces 13b are outer surfaces that extend in a direction intersecting the rotation axis of the worm 10. The vertical surfaces 13c, 13f, and 13g extend in a direction perpendicular to the rotation axis of the worm 10. The vertical surfaces 13c, 13f, and 13g are outer surfaces that extend in a direction intersecting the rotation axis of the worm 10, and may also be inclined surfaces that extend in a direction oblique to the rotation axis of the worm 10.

[0032] The vertical surface 13f is located between the outer peripheral surface 13d and the outer peripheral surface 13e in the axial and radial directions, and extends in the circumferential direction. The vertical surface 13f is formed substantially flush with the radially outward side of the multiple vertical surfaces 13c. The vertical surface 13g is located between the apex 13a and the slope 13b in the axial and radial directions, and extends in the circumferential direction.

[0033] As shown in Figure 8, a portion of the worm 10 located between one end 16 and the other end 13 is a cylindrical portion 11. Teeth 12 that mesh with the first transmission gear 61 are formed on the outer peripheral surface of this cylindrical portion 11, and the teeth 12 form a part of the outer surface of the worm 10. As shown in Figure 11, a cavity 14 is formed in the cylindrical portion 11 of the worm 10, extending in the direction of the rotation axis of the worm 10. The cavity 14 comprises one end 14a on the side of the one end 16 of the worm 10 and the other end 14b on the side of the other end 13 of the worm 10.

[0034] In the rotation axis direction of the worm 10, a recess 16a is formed at one end 16 of the worm 10, recessed toward the cavity 14. As shown in Figure 8, a gate mark 18 for injecting resin material is formed on the outer peripheral surface of one end 16 of the worm 10. Also, as shown in Figure 11, a plurality of recesses 17 are formed on the outer peripheral surface of one end 16 of the worm 10 in the circumferential direction. This recess 16a and the plurality of recesses 17 are connected, forming a single space.

[0035] As shown in Figure 10, the rotating shaft 31 of the motor 3 is mounted in the cavity 14 of the worm 10. In the X-axis direction, the cavity 14 is connected to the recess 16a of the worm 10, and one end 14a of the cavity 14 is open toward the recess 16a. In the rotation axis direction of the worm, the other end 14b of the cavity 14 faces the portion that forms the top 13a of the other end 13 of the worm 10, as shown in Figure 11. That is, the other end 14b of the cavity 14 is closed. Also, a top 13a is formed on a portion of the outer peripheral surface of the other end 13 of the worm 10.

[0036] In the circumferential direction, a plurality of (three or more in this embodiment) recesses 15 are formed on the outer peripheral surface of the other end 13 of the worm 10, each having a hole 15c that connects to a cavity 14. These plurality of recesses 15 have a concave shape in the direction of the rotation axis of the worm 10. Furthermore, the plurality of recesses 15 have a concave shape in the radial direction on the outer peripheral surface of the other end 13 of the worm 10. Specifically, the recess 15 comprises an inner surface 15a extending in the direction of the rotation axis of the worm 10, a portion of the vertical surface 13c (described later), and two inner surfaces 15b located on both sides of the inner surface 15a and the vertical surface 13c in the circumferential direction.

[0037] The inner surface 15a is located radially inward relative to the outer peripheral surface 13d. The inner surface 15a has a hole 15c (referred to as a communication hole in subsequent paragraphs) that connects radially to the cavity 14. That is, the cavity 14 is formed radially inside a plurality of recesses 15, and the space inside the recesses 15 is connected to the cavity 14 via the hole 15c. The two inner surfaces 15b face each other in the circumferential direction.

[0038] The vertical surface 13c comprises a portion located inside the outer peripheral surface 13d in the radial direction and a portion surrounding the outer peripheral surface 13d in the circumferential direction. The vertical surfaces 13c and 13f form a stepped portion on the outer peripheral surface of the worm 10 and extend in a direction intersecting the outer peripheral surfaces 13d and 13e (a direction perpendicular in this embodiment). Furthermore, the vertical surface 13c forms the bottom surface of the recess 15 in the rotation axis direction of the worm 10. The recess 15 is open toward the other side in the rotation axis direction.

[0039] The other end 13 of the worm 10 is formed continuously with the cylindrical portion 11 on the negative side of the X-axis. In the X-axis direction, the apex 13a, which is the tip of the other end 13, is formed as a curved surface, as shown in Figure 11. In the rotation axis direction of the worm 10, the cross-sectional shape of the apex 13a is formed as a curved shape (e.g., arc-shaped). Specifically, the apex 13a of the other end 13 is formed as a hemisphere.

[0040] The outer peripheral surface of the other end 13 of the worm 10 is rotatably supported by a second housing 22, which is another component, with the circumferential direction being the rotational direction. That is, the outer peripheral surface of the worm 10 is in contact with the second housing 22 and rotates relative to the second housing 22 with the circumferential direction being the rotational direction. Specifically, the top 13a of the other end 13 of the worm 10 is supported by a wall 25 of the second housing 22. The wall 25 has a recess 25a formed in it, for example, at a position corresponding to the top 13a. In this case, the top 13a becomes the pivot on the other end 13 side of the worm 10. Note that the recess 25a of the second housing 22 is an example of a part of the housing.

[0041] Three recesses 15 are formed at the other end 13 of the worm 10. The cavity 14 is located radially inward relative to the recesses 15. In other words, the recesses 15 are located radially outward relative to the cavity 14. Note that there may be one or more recesses 15.

[0042] Multiple recesses 15 extend in the X-axis direction. Communication holes 15c that communicate with the cavity 14 are formed on the inner surface 15a that forms the recesses 15. The communication holes 15c are formed in the radial direction at a position opposite to the cavity 14. Multiple recesses 15 are formed at equal intervals in the circumferential direction of the other end 13, that is, in the rotational direction of the worm 10.

[0043] The outer peripheral surface of the other end 13 of the worm 10 has one or more annular marks 19. In this embodiment, the multiple annular marks 19 are circumferentially extending protrusions 19a and 19b formed on the outer peripheral surface of the worm 10. Specifically, at the other end 13 of the worm 10, a protrusion 19a is formed on the vertical surface 13g surrounding the apex 13a, and a protrusion 19b is formed on the vertical surface 13c surrounding the outer peripheral surface 13d. These protrusions 19a and 19b project from the vertical surface 13c and the vertical surfaces 13f and 13g, respectively, in the rotation axis direction of the worm 10.

[0044] The convex portion 19a is located near the boundary between the apex 13a and the slope 13b in the radial direction. The convex portion 19b is located near the boundary between the outer peripheral surface 13d and the outer peripheral surface 13e in the radial direction. In the rotation axis direction of the worm 10, a part of the recess 15 and a part of the outer peripheral surface 13d of the other end 13 are located between the convex portion 19a and the convex portion 19b. In this embodiment, the convex portions 19a and 19b are formed, for example, in a substantially concentric shape. In the following, when the convex portions 19c and 19b are not distinguished, they may simply be referred to as convex portion 19.

[0045] The protrusion 19 is formed at a position corresponding to the gas vent 89 formed on the pin 80, which will be described later. Also, as shown in Figure 9, the protrusion 19a is formed on the outer peripheral surface that is inside the recess 15 in the circumferential direction. In this embodiment, the protrusion 19 is formed in a concentric shape and extends in the circumferential direction. Note that the concentrically formed protrusion 19 is a continuous ring-shaped mark and is an example of a ring-shaped mark.

[0046] As shown by arrow D1 in Figure 11, the protrusion 19 is located on the negative X-axis side relative to the cavity 14, that is, on the side of the apex 13a.

[0047] Next, the molding method for the worm 10 will be described using Figures 12 to 14. Figure 12 is a cross-sectional view illustrating an example of a mold in the embodiment. Figure 13 is a cross-sectional view showing an example of the molding method for the worm in the embodiment. Figure 14 is an enlarged cross-sectional view illustrating an example of the molding method for the worm in the embodiment. Figure 14 is an enlarged view of the portion shown in frame F1 of Figure 13. The worm 10 is formed by injection molding using molds 71, 72, 73 and pins 74, 75, 80.

[0048] Mold 71 has holes 71a into which pins 74 and 80 are inserted, and mold 72 has a hole 72a into which pin 75 is inserted. Mold 72 also has a gate portion (not shown) into which resin is injected. Mold 73 has a molding surface 73a that forms the outer shape of the teeth 12 of the worm 10.

[0049] The pin 80, which is inserted into the mold 71, has a molding surface 80b that forms a slope 13b at the other end 13 of the worm 10, and a molding surface 80f that forms a vertical surface 13f. The pin 80 also has three protrusions 81 that form recesses 15 having communication holes 15c at the other end 13 of the worm 10. The number of protrusions 81 corresponds to the number of recesses 15. The protrusions 81 have molding surfaces 81c that form the vertical surface 13c. The pin 80 also has a hole 80a for inserting a pin 74.

[0050] Furthermore, multiple gas vents 89a and 89b are formed on the pin 80. In this embodiment, gas vent 89a is formed radially outward from gas vent 89b. In the following, when gas vents 89a and 89b are not distinguished, they may simply be referred to as gas vent 89.

[0051] As shown in Figure 12, in the rotation axis direction of the worm 10, one opening of the gas vent 89a is located on the molding surface 80g, and the other opening is located on the other end 74x of the pin 74. Similarly, one opening of the gas vent 89b is located on the molding surface 81c, and the other opening is located on the other end 80x of the pin 80. In other words, as shown in Figure 12, the gas vent 89 is a communication hole (hole) formed on the inner and outer circumferences of the pin 80, extending in the longitudinal direction of the worm. As shown in Figure 13, in this embodiment, the gas vent 89b is along the outer peripheral surface 81a of the protrusion 81 in the rotation axis direction of the worm 10.

[0052] The pin 74, which is inserted into the pin 80, has a roughly hemispherical forming surface 74a that forms the outer circumferential surface (outer surface) 13a1 of the other end 13 of the worm 10.

[0053] The pin 75, which is inserted into the mold 72, has a radially outward projecting portion 75a that forms a recess 16a at one end 16 of the worm 10.

[0054] When forming the worm 10, as shown in Figure 12, the mold 73 is assembled such that one end of the mold 73 is in contact with the mold 72 and the other end of the mold 73 is in contact with the mold 71 in the direction of rotation of the worm 10. With pins 74 and 80 inserted into mold 71 and pin 75 inserted into mold 72, molds 71 ​​and 72 are moved to a predetermined forming position so that they are in contact with mold 71 in the direction of rotation of the worm. As a result, as shown in Figure 12, the molds 71, 72, 73 and pins 74, 75, 80 form a cavity 79, which is the gap for forming the worm 10.

[0055] The three protrusions 81 contact the pins 75 that are inserted through the molds 72 and 73. As a result, in the rotation axis direction of the worm 10, the tips of the protrusions 81 of the pins 80 are supported by the pins 75. As shown in Figure 14, the portion where the protrusions 81 of the pins 80 and the pins 75 face each other in the radial direction forms a communication hole 15c between the cavity 14 and the recess 15 of the worm 10.

[0056] Then, the heated and melted resin is injected under high pressure from the gate of the mold 72 into the cavity 79, filling the cavity 79 with resin and molding the worm 10, as shown in Figure 13. At this time, compressed air in the mold and gases generated from the resin being filled are released to the outside of the mold through the gas vent 89. This suppresses the occurrence of resin filling defects and voids. When air and gases are released from the gas vent 89, some of the molten resin also flows out toward the gas vent 89. In this case, the protrusion 19 of the worm 10 is formed at a position opposite the opening of the gas vent 89 on the cavity 79 side. Furthermore, since the pin 80 is supported by the projection 81, bending of the tip of the pin 80 is suppressed even when the resin is injected under high pressure.

[0057] Then, after the resin has cooled, the molds 71, 72, 73 and pins 74, 75, 80 are moved to separate the worm 10 from the mold. In this configuration, the resin that flows out from the vertical surfaces 13c and 13f of the other end 13 toward the gas vent 89 solidifies on the worm 10, forming multiple protrusions 19 at positions corresponding to the gas vent 89, as shown in Figure 14. With this configuration, the fluidity of the resin in injection molding is improved, and the accuracy of the worm can be improved.

[0058] As shown in Figures 11 and 14, the top portion 13a comprises a curved outer circumferential surface 13a1 and a cylindrical outer circumferential side surface (outer surface) 13a2. The convex portion 19a is located radially outward (towards the inclined surface 13b) relative to the curved outer circumferential surface 13a1 and the cylindrical outer circumferential side surface 13a2. Furthermore, in the rotation axis direction of the worm 10, the convex portion 19a is located toward the cylindrical portion 11 relative to the curved outer circumferential surface 13a1. On the other hand, the convex portion 19b is located radially outward (towards the teeth 12) relative to the top portion 13a. In other words, radially, the top portion 13a is located inward relative to the convex portion 19b. Furthermore, in the rotation axis direction of the worm 10, the convex portion 19b is located toward the positive X-axis direction, i.e., toward the cylindrical portion 11, relative to the top portion 13a. With this configuration, the convex portion 19 is located at a different position from the contact surface between the top portion 13a and the recess 25a of the wall 25 of the housing 2 in the rotation axis direction of the worm 10, so that the top portion 13a is rotatably supported by the recess 25a.

[0059] As described above, the worm 10 in the embodiment is a resin worm formed by injection molding. The worm 10 comprises a cylindrical portion 11 as a part having teeth 12, one end 16, and the other end 13 having a top. The cylindrical portion 11 has a cavity 14 with a long axis as its axis, and in the circumferential direction, there is one or more annular marks 19 on the outer peripheral surface of the other end 13. With this configuration, the accuracy of the worm 10 can be improved. In addition, the rotating device 1 is equipped with the worm 10, and the rotating device 1 can be made quieter. [Example 1]

[0060] The configuration of this embodiment has been described above, but the embodiment is not limited thereto. For example, the annular mark corresponding to the position of the gas vent is not limited to that shown in the embodiment, but may be a discontinuous annular arrangement of marks, a mark that is part of a ring, or an arc mark, as shown in Figure 15 and subsequent figures. Figure 15 is a perspective view showing an example of the positional relationship between the hassba gear and the worm in the first modified example. Figure 16 is a cross-sectional view showing an example of the worm in the first modified example. In each of the following modified examples, the same reference numerals are used for parts that are the same as those shown in the drawings described earlier, and redundant explanations are omitted.

[0061] As shown in Figures 15 and 16, in the first modified example, the other end A13 of the worm A10 has convex portions 19c and 19d on the inclined surface A13b surrounding the apex 13a, projecting to the other side in the X-axis direction. The convex portions 19c and 19d are formed, for example, in a substantially concentric shape. In the following, when the convex portions 19c and 19b are not distinguished, they may simply be referred to as convex portion A19. Also, in the first modified example, convex portions 19a and 19b are not formed on the vertical surfaces A13c, A13f and A13g.

[0062] The protrusions 19c and 19d are formed at positions corresponding to the gas vents 89c and 89d formed on the pin A80 shown in Figures 17 and later. Furthermore, the protrusion 19 is formed on the inside of the recess 15 in the circumferential direction, as shown in Figures 16 and later. In the first modified example, the protrusion A19 is formed in a concentric shape and extends in the circumferential direction.

[0063] As shown by arrow D1 in Figure 11, the protrusion 19 is located on the negative X-axis side relative to the cavity 14, that is, on the side of the apex 13a.

[0064] Next, the method for forming the worm A10 in the first modified example will be described with reference to Figures 17 to 19. Figure 17 is a cross-sectional view illustrating an example of a mold in the first modified example. Figure 18 is a cross-sectional view showing an example of the method for forming the worm in the first modified example. Figure 19 is an enlarged cross-sectional view illustrating an example of the method for forming the worm in the first modified example. Figure 19 is an enlarged view of the portion shown in frame F2 of Figure 18. The worm A10 in the first modified example is formed by injection molding using molds A71, 72, 73 and pins A74, 75, A80.

[0065] The mold A71 has holes A71a into which pins A74 and A80 are inserted. Pin A80, which is inserted into the mold A71, has a molding surface A80b that forms the bevel A13b at the other end 13 of the worm A10. Pin A80 also has a hole A80a into which pin A74 is inserted.

[0066] Multiple gas vents 89c and 89d are formed on pin A80. In the first modified example, gas vent 89c is formed radially outward from gas vent 89d. In the following, when gas vents 89c and 89d are not distinguished, they may simply be referred to as gas vent A89. In the modified example, gas vent A89 does not face the molded surfaces A80f and A81c.

[0067] One opening of the gas vent A89 in the longitudinal direction is located on the molded surface A80b, and the other opening is located on the other end A80g of the pin A80. In other words, as shown in Figure 17, the gas vent A89 is a communication hole that extends in the longitudinal direction and is formed to penetrate the pin A80. Note that, as shown in Figure 17, in the first modified example, the gas vent A89 is formed in the longitudinal direction and is spaced apart from the outer peripheral surface A81a of the protruding portion A81.

[0068] As shown in Figure 17, the molds A71, 72, 73 and pins A74, 75, A80 form a cavity A79, which is the gap for forming the worm A10. In addition, the gas vent 89 in the embodiment is formed to extend circumferentially as shown in Figure 9, but in the first modified example, the gas vent A89 is formed intermittently in the circumferential direction as shown in Figure 15.

[0069] Even with this configuration, the fluidity of the resin in injection molding is improved, thus enhancing the accuracy of the worm gear.

[0070] Furthermore, as shown by arrow D2 in Figures 16 and 19, the protrusion A19 is formed on the positive X-axis side, i.e., on the side of the cylindrical portion 11, relative to the apex 13a. Also, as shown by arrow D3 in Figure 19, the protrusion A19 is formed on the outward Y-axis side, i.e., on the side of the teeth 12, relative to the apex 13a. Even in this configuration, the protrusion 19 does not obstruct contact between the apex 13a and the housing 2.

[0071] [Differentiation 2] Furthermore, in the embodiment, as shown in Figure 14, gas vents 89a and 89b are formed substantially concentrically on the outer and inner sides in the radial direction, respectively, and in the first modified example, as shown in Figure 19, gas vents 89c and 89d are formed substantially concentrically on the outer and inner sides in the radial direction, respectively, but the embodiments are not limited to these. For example, there may be only one gas vent 89 formed in the radial direction, or there may be three or more arranged side by side. In any configuration, the protrusion of the worm is formed at a position opposite to the gas vent in the longitudinal direction, similar to the protrusion 19 of the worm 10 shown in Figure 14.

[0072] Furthermore, as shown in Figure 4, motor 3 is a so-called "square motor" with a roughly square cross-section, but it is not limited to this, and may have any shape, such as a roughly circular cross-section.

[0073] Furthermore, the support relationship between the worm 10 and the housing 2 is not limited to those shown in the embodiment and each modified example. For example, the top 13a of the other end 13 of the worm 10 may be supported by a portion of the second housing 22 other than the recess, or the outer peripheral surface 13d of the other end 13 of the worm 10 may be supported by the second housing 22. Alternatively, any portion of the other end 13 may be supported by any portion of the first housing 21 instead of the second housing 22. In addition, the housing 2 may be provided with other members to support the other end 13.

[0074] Furthermore, the gas vent 89 in this embodiment is, for example, a communication hole formed in the pin 80 as shown in Figure 12, but is not limited to this. For example, a gap formed at the boundary between the mold 71 and the pin 80, or at the boundary between the pin 74 and the pin 80, may also function as a gas vent.

[0075] Although the present invention has been described above based on embodiments and various modifications, it goes without saying that the present invention is not limited to embodiments and various modifications, and that various modifications are possible without departing from the spirit of the invention. Various modifications that do not depart from the spirit are also included in the technical scope of the present invention, and this will be clear to those skilled in the art from the description of the claims. [Explanation of Symbols]

[0076] 1 Rotating device, 2 Housing, 3 Motor, 4 Terminal group, 5 Output gear, 6 Gear group, 7 Sensor, 10, A10 Worm, 11 Cylindrical section, 12 Teeth, 13, A13 Other end, 13a Top, 13a1 Outer surface, 13b, A13b Sloping surface, 13c, 13f, 13g, A13c, A13f, A13g Vertical surface, 13a2, 13d, 13e Outer side surface, 14 Cavity, 15 Recess, 15c Communication hole, 16 One end, 17 Recess, 18 Gate mark, 19, A19 Protrusion, 21 First housing, 22 Second housing, 28 Projection, 30 Frame, 31 Rotating shaft, 32 Cylindrical body, 34 First end, 35 Second end, 51 Output shaft, 61 First transmission gear, 61a Helical gear, 61b Gear, 62 Second transmission gear, 71-73, A71 Mold, 74, 75, 80, A74, A80 Pin, 81, A81 Protrusion, 89, A89 Gas vent, 91 Projection, 92 Fitting hole, 93 Joining piece, 94 Connecting hole, 210 First face, 211 First side wall, 212 Engaging part, 214 Opening, 215 Engaging recess, 220 Second face, 222 Second side wall, 224 Engaging projection, 226 Opening, 281 First through hole, 282 Second through hole, 341 First bearing part, 342 First outer surface, 349 First bearing

Claims

1. A resin worm formed by injection molding, A portion having teeth, one end, and the other end having a apex, Equipped with, The aforementioned portion includes a cavity extending in the direction of the rotation axis, The other end comprises an outer surface surrounding the top, a plurality of outer peripheral surfaces, a cylindrical outer peripheral surface, and a stepped portion formed between the plurality of outer peripheral surfaces and the cylindrical outer peripheral surface. The stepped portion surrounds the plurality of outer peripheral surfaces, In the radial direction, the outer surface surrounding the top portion is located inside the plurality of outer peripheral surfaces. In the circumferential direction, the outer surface surrounding the top portion and the stepped portion have annular marks. Warm.

2. The worm according to claim 1, wherein the annular mark is a convex portion extending in the circumferential direction.

3. The other end is, In the radial direction, it has multiple recesses, In the direction of rotation, a portion of the recess is located between the annular mark on the outer surface surrounding the top and the annular mark on the stepped portion. A worm according to claim 1 or 2.

4. The aforementioned top is, It has an outer surface that is rotatably supported by another member, A worm according to claim 1 or 2.

5. The worm is as described in claim 4, and the gear meshes with the worm, A motor having a rotating shaft positioned in the aforementioned cavity, A housing that houses the motor, the gear, and the worm, Equipped with, The other component is a part of the housing or a component provided on the housing, wherein the rotating device.

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