Gear housing for a planetary gear device structurally separating the ring gear

Abstract

The present application provides an apparatus for suppressing noise generated in a planetary gear device, a planetary gear device, and an actuator. The apparatus for suppressing noise generated in a planetary gear device includes an inner gear having a first protrusion portion formed on an outer peripheral surface of the inner gear, the first protrusion portion extending in an axial direction from one side of the inner gear to the other side of the inner gear, wherein the first protrusion portion is formed in a first direction inclined with respect to the axial direction; and a housing having a second protrusion portion formed on an inner surface of the housing, the second protrusion portion extending in a second direction inclined with respect to the axial direction, wherein the housing is configured to accommodate the inner gear inside the housing such that a gap is generated between an inner peripheral surface of the housing and an outer peripheral surface of the inner gear, and wherein movement of the inner gear in the inside of the housing is restricted by line contact between the first protrusion portion and the second protrusion portion.

Description

TECHNICAL FIELD

[0001] The present application relates to a separated structure unit for a ring gear and a housing, a planetary gear device including the separated structure unit, and an actuator including the planetary gear device. BACKGROUND

[0002] A planetary gear device is used in various technologies such as automobiles, robots, and the like. Since a planetary gear device is configured by a combination of a plurality of gears, noise and vibration are generated during operation. A technique has been proposed to suppress generation of noise and vibration when a planetary gear device is operated.

[0003] As one of such techniques that have been proposed, Patent Literature 1 discloses a planetary gear device having a structure in which a ring gear and a housing are separated so that a gap is provided between the ring gear and the housing. Use of a structure in which a ring gear and a housing are separated makes it more difficult for vibration to be transmitted from the ring gear to the housing, thereby reducing noise generated by vibration.

[0004] [LIST OF CITATIONS]

[0005] [PTENT LITERATURE]

[0006] [Patent Literature 1] Japanese Unexamined Patent Application Publication H06-074835 SUMMARY

[0007] [TECHNICAL PROBLEM]

[0008] In the planetary gear device of Patent Literature 1, an outer peripheral surface of the ring gear and an inner peripheral surface of the housing are formed with shapes that fit together. Therefore, when the ring gear moves during operation of the planetary gear device, there is contact between the outer peripheral surface of the ring gear and the inner peripheral surface of the housing, and the range of contact has a certain degree of width. Due to this, in a state in which there is contact between the ring gear and the housing, vibration of the planetary gear mechanism that is propagated to the ring gear is easily transmitted to the housing, and therefore there is a problem in that the planetary gear device also has a tendency to generate noise.

[0009] The present application aims to solve the problem area such as described above, and the object is to provide a separated structure unit for a ring gear and a housing, capable of suppressing transmission of vibration from a planetary gear mechanism and noise generated by a planetary gear device, and capable of providing a planetary gear device equipped with the separated structure unit and an actuator equipped with the planetary gear device.

[0010] [TECHNICAL SOLUTION]

[0011] A separate structural unit for a ring gear and a housing according to the present application includes a ring gear having a first protruding portion formed on an outer peripheral surface thereof, the first protruding portion extending from one side in an axial direction to the other side in the axial direction in a direction oblique with respect to the axial direction, and a housing having a second protruding portion formed on an inner peripheral surface thereof, the housing being used to house the ring gear in a state in which a gap from the inner peripheral surface is provided therein, wherein movement of the ring gear inside the housing is restricted by line contact between the first protruding portion and the second protruding portion.

[0012] In another aspect of the present application, a separate structural unit for a ring gear and a housing includes a ring gear having a plurality of first protruding portions formed on an outer peripheral surface thereof and a contact portion between adjacent first protruding portions, and a housing having a second protruding portion formed on an inner peripheral surface thereof, the housing being used to house the ring gear in a state in which a gap from the inner peripheral surface is provided therein, wherein movement of the ring gear inside the housing is restricted by contact of the first protruding portions and the second protruding portion, and movement inside the housing is restricted by contact of the contact portion and the inner peripheral surface of the housing, and an opening provided in the axial direction is formed on an inner side of the contact portion of the ring gear.

[0013] In another aspect of the present application, a separate structural unit for a ring gear and a housing includes a ring gear having a plurality of first protruding portions formed on an outer peripheral surface thereof, the first protruding portions extending in a prescribed direction, and a housing having a plurality of second protruding portions formed on an inner peripheral surface thereof, the housing being used to house the ring gear in a state in which a gap from the inner peripheral surface is provided therein, wherein movement of the ring gear inside the housing is restricted by line contact of the first protruding portions and corresponding second protruding portions, and the plurality of first protruding portions and the plurality of second protruding portions are provided to be each equally spaced apart.

[0014] In another aspect of the invention, a structural unit for separating an internal gear and a housing includes: an internal gear, wherein a plurality of first protrusions extending in a predetermined direction are formed on an outer peripheral surface; and a housing, wherein a plurality of second protrusions extending in the predetermined direction are formed on an inner peripheral surface of the housing, the housing being configured to receive the internal gear in a state in which a gap is provided with the inner peripheral surface therein, wherein: movement of the internal gear within the housing is restricted by line contact between the first protrusions and corresponding second protrusions; and the plurality of first protrusions and the plurality of second protrusions are configured such that each adjacent protrusion is spaced unequally apart.

[0015] In the first protruding portion and the second protruding portion, one protruding portion may be formed as a pair with a gap between them, and another protruding portion may be configured to be easily inserted between the pair of protruding portions; and in the contact position of the one protruding portion that contacts each other and the contact position of the other protruding portion, at least one contact position may be a curved surface.

[0016] The one protruding portion may be the second protruding portion, and the other protruding portion may be the first protruding portion; and when cut by a plane perpendicular to the axial direction, the first protruding portion may have a triangular cross-section, and the first protruding portion may contact the second protruding portion at an inclined surface formed in the plane.

[0017] The protruding portion may be the first protruding portion, and the other protruding portion may be the second protruding portion; and when cut by a plane perpendicular to the axial direction, the second protruding portion may have a triangular cross-section, and the second protruding portion may contact the first protruding portion at an inclined surface formed in the plane.

[0018] In the contact positions of the first protrusion and the second protrusion, one contact position may be a convex surface and the other contact position may be a plane.

[0019] The contact positions of the first protrusion and the second protrusion, which are in contact with each other, can be convex curved surfaces.

[0020] In the contact positions of the first protrusion and the second protrusion, one contact position may be a convex surface and the other contact position may be a concave surface.

[0021] The first protrusion may be an external tooth structure cut along the axial direction or in a direction inclined relative to the axial direction on the outer peripheral surface of the internal gear; and the second protrusion may be an internal tooth structure cut along the axial direction or in a direction inclined relative to the axial direction on the inner peripheral surface of the housing.

[0022] Each of the plurality of first protruding portions may be provided with a corresponding second protruding portion, wherein a portion of the plurality of second protruding portions may contact the corresponding first protruding portion when the internal gear rotates in a first direction, and the remaining portions may contact the corresponding first protruding portion when the internal gear rotates in a second direction.

[0023] The internal gear and the housing may be made of synthetic resin; and the internal gear may be formed of a synthetic resin with a lower hardness than the synthetic resin used to form the housing.

[0024] The planetary gear assembly according to the invention comprises: a structural unit for separating the internal gear and the housing as described above; one or more planetary gears meshing with the internal gear; a sun gear meshing with the one or more planetary gears and positioned at the center of the one or more planetary gears; and a support rotatably supporting the one or more planetary gears.

[0025] The structure may further include a second sun gear that rotates in a manner similar to the rotation of the support as the support rotates; one or more second planetary gears disposed on the periphery of the second sun gear and meshing with the second sun gear; a second support that rotatably supports the one or more second planetary gears; and a second housing with internal teeth meshing with the one or more second planetary gears formed on the inner peripheral surface of the second housing, wherein the housing and the second housing may be integrally formed.

[0026] In another aspect of the invention, the planetary gear assembly includes at least two stages of planetary gear mechanisms, each stage comprising: a sun gear; one or more planetary gears arranged on the periphery of the sun gear for meshing with the sun gear; and a support rotatably supporting the one or more planetary gears, wherein: in the at least two stages of planetary gear mechanisms, the planetary gear mechanism operating at the highest speed includes the structural unit for separating the internal gear and the housing as described above, wherein the one or more planetary gears of the planetary gear mechanism mesh with the internal gear; and in the at least two stages of planetary gear mechanisms, the planetary gear mechanism operating at the lowest speed includes a housing, wherein the internal teeth meshing with the one or more planetary gears of the planetary gear mechanism are formed on an inner peripheral surface.

[0027] The actuator according to the invention comprises: a planetary gear assembly as described above; and a motor connected to the planetary gear assembly for driving the planetary gear assembly.

[0028] In one aspect of the invention, an apparatus for suppressing noise generated in a planetary gear assembly includes: an internal gear and a housing, the internal gear having a first protrusion formed on an outer peripheral surface of the internal gear, the first protrusion extending axially from one side of the internal gear to the other side of the internal gear, wherein the first protrusion is formed in a first direction inclined relative to the axial direction; the housing having a second protrusion formed on an inner surface of the housing, the second protrusion extending in a second direction inclined relative to the axial direction, wherein the housing is configured to receive the internal gear within the housing such that a gap is created between the inner peripheral surface of the housing and the outer peripheral surface of the internal gear, and wherein movement of the internal gear within the housing is restricted by line contact between the first protrusion and the second protrusion.

[0029] In another aspect of the invention, an apparatus for suppressing noise generated in a planetary gear assembly includes: an internal gear and a housing, the internal gear having a plurality of first protrusions and contact portions, the contact portions being located on adjacent first protrusions, wherein the plurality of first protrusions and the contact portions are all formed on the outer peripheral surface of the internal gear; the housing having a second protrusion formed on the inner peripheral surface of the housing, wherein the housing is configured to receive the internal gear such that a gap is provided between the inner peripheral surface of the housing and the outer peripheral surface of the internal gear, wherein movement of the internal gear within the housing is restricted by contact between the first protrusions and the second protrusions, and movement within the housing is restricted by contact between the contact portions and the inner peripheral surface of the housing, and wherein an opening is formed inside the contact portions of the internal gear, the opening being axially oriented toward the internal gear.

[0030] In another aspect of the invention, an apparatus for suppressing noise generated in a planetary gear assembly includes: an internal gear and a housing, the internal gear having a plurality of first protrusions formed on an outer peripheral surface of the internal gear, each of the plurality of first protrusions extending in a direction; the housing having a plurality of second protrusions formed on an inner peripheral surface of the housing, each of the plurality of second protrusions extending in the direction, wherein the housing is configured to receive the internal gear such that a gap is formed between the inner peripheral surface and the outer peripheral surface, wherein movement of the internal gear within the housing is limited by linear contact between the first protrusions and the corresponding second protrusions; and wherein the plurality of first protrusions and the plurality of second protrusions are respectively spaced approximately equidistantly around the internal gear and the housing.

[0031] In another aspect of the invention, an apparatus for suppressing noise generated in a planetary gear assembly includes: an internal gear and a housing, the internal gear having a plurality of first protrusions formed on the outer peripheral surface of the internal gear and extending in one direction; the housing having a plurality of second protrusions formed on the inner peripheral surface of the housing, the second protrusions extending in the direction, wherein the housing is configured to receive the internal gear such that a gap is provided between the inner peripheral surface and the outer peripheral surface, wherein movement of the internal gear within the housing is restricted by linear contact between the first protrusions and the corresponding second protrusions, and wherein the plurality of first protrusions and the plurality of second protrusions are non-equidistantly spaced around the internal gear and the housing, respectively.

[0032] In some embodiments, one of the first and second protruding portions is formed in pairs and has a gap between the paired protruding portions, the other protruding portion is configured to be inserted between the paired protruding portions, and the surface on one of the first and second protruding portions that contacts the surface on the other protruding portion is a curved surface.

[0033] In some embodiments, the second protrusions are formed in pairs with the interval between the pairs of second protrusions, and the first protrusion is configured to be inserted between the second protrusions, wherein when truncated by a plane perpendicular to the axial direction, the first protrusion has a triangular cross-section and contacts the second protrusion at an inclined surface formed in the plane.

[0034] In some embodiments, the first protrusions are formed in pairs and have the interval between the pairs of first protrusions, wherein the second protrusion is configured to be inserted between the first protrusions, and wherein when truncated by a plane perpendicular to the axial direction, the second protrusion has a triangular cross-section and contacts the first protrusion at an inclined surface formed in the plane.

[0035] In some embodiments, at the contact position between the first protrusion and the second protrusion, the surface of one of the protrusions is a convex curved surface, and the surface of the other protrusion is a flat surface.

[0036] In some embodiments, at the contact position between the first protrusion and the second protrusion, the surfaces of the first protrusion and the second protrusion are convex curved surfaces.

[0037] In some embodiments, at the contact position between the first protrusion and the second protrusion, the surface of one of the protrusions is a convex surface, and the surface of the other protrusion is a concave surface.

[0038] In some embodiments, the first protrusion includes external teeth cut along the axial direction or in a direction inclined relative to the axial direction, and the second protrusion includes internal teeth cut along the axial direction or in a direction inclined relative to the axial direction.

[0039] In some embodiments, each of the plurality of first protrusions is provided with a corresponding second protrusion, wherein when the internal gear rotates in a first direction, one of the plurality of second protrusions contacts the corresponding first protrusion; and when the internal gear rotates in a second direction, a different one of the plurality of second protrusions contacts the corresponding first protrusion.

[0040] In some embodiments, the internal gear and the housing are made of synthetic resin, and the internal gear is formed of a synthetic resin with a lower hardness than the synthetic resin used to form the housing.

[0041] In another aspect of the invention, a planetary gear assembly includes: a device for suppressing noise generated in the planetary gear assembly as described above; at least one planetary gear meshing with the internal gear; a sun gear meshing with and located at the center of the one or more planetary gears; and a support rotatably supporting the one or more planetary gears.

[0042] In some embodiments, the device further includes: a second sun gear that rotates in a manner similar to the rotation of the support as the support rotates; one or more second planetary gears disposed on the periphery of the second sun gear and meshing with the second sun gear; a second support that rotatably supports the one or more second planetary gears; and a second housing with internal teeth meshing with the one or more second planetary gears formed on the inner peripheral surface of the second housing, wherein the housing and the second housing are integrally formed.

[0043] In another aspect of the invention, a planetary gear device includes at least two stages of planetary gear mechanisms, each stage comprising: a sun gear; one or more planetary gears arranged on the periphery of the sun gear for meshing with the sun gear; and a support rotatably supporting the one or more planetary gears, wherein in the at least two stages of planetary gear mechanisms, the planetary gear mechanism operating at a higher speed includes the aforementioned device for suppressing noise generated in the planetary gear device, wherein the one or more planetary gears of the planetary gear mechanism mesh with the internal gear, and wherein in the at least two stages of planetary gear mechanisms, the planetary gear mechanism operating at a lower speed includes a second housing, wherein the internal teeth meshing with the one or more planetary gears of the planetary gear mechanism are formed on the inner peripheral surface of the second housing.

[0044] In another aspect of the invention, an actuator includes: a planetary gear assembly as described above; and a motor connected to the planetary gear assembly for driving the planetary gear assembly.

[0045] [Technical Effects]

[0046] In this invention, the contact range between the internal gear and the housing is narrower than that in the prior art, thereby reducing the transmission of vibrations caused by the planetary gear mechanism to the housing. This suppresses the transmission of vibrations from the planetary gear mechanism and also suppresses the noise generated by the planetary gear assembly that accompanies the vibrations of the planetary gear mechanism.

[0047] [Technical Issues]

[0048] A separate structural unit is provided for the internal gear and the housing, which suppresses vibrations transmitted from the planetary gear mechanism and suppresses noise generated by the planetary gear assembly.

[0049] [Technical solutions to solve problems]

[0050] A structural unit for separating an internal gear and a housing includes: an internal gear, wherein a first protrusion extending in a direction inclined relative to the axial direction is formed on an outer peripheral surface; and a housing, wherein a second protrusion extending in the same direction is formed on an inner peripheral surface, and the housing accommodates the internal gear with a gap between it and the inner peripheral surface. Movement of the internal gear within the housing is restricted by line contact between the first and second protrusions. Attached Figure Description

[0051] Figure 1 This is a perspective view of an actuator according to a first embodiment of the present invention.

[0052] Figure 2 From Figure 1 Arrow AII in the diagram shows the front view of the actuator.

[0053] Figure 3 In order to be in Figure 2 The cross-sectional view of the actuator taken from section line III-III in the diagram.

[0054] Figure 4 This is an assembly perspective view of the actuator according to a first embodiment of the present invention.

[0055] Figure 5 This is a cross-sectional view of the second housing according to a first embodiment of the present invention.

[0056] Figure 6 This is a perspective view of the second housing according to a first embodiment of the present invention.

[0057] Figure 7 This is a perspective view of a first planetary gear mechanism according to a first embodiment of the present invention.

[0058] Figure 8 This is a perspective view of a second planetary gear mechanism according to a first embodiment of the present invention.

[0059] Figure 9 This is a diagram illustrating the relationship between the second housing and the internal gear according to a first embodiment of the present invention.

[0060] Figure 10 To focus on the formation of Figure 9 An illustrative diagram of the stop in the second housing shown.

[0061] Figure 11 To focus on the formation of Figure 9 An illustrative diagram of the movement-limiting protrusion on the internal gear shown.

[0062] Figure 12 For the purpose of illustration Figure 9 The diagram shows the state in which the internal gear rotates about its axis and comes into contact with the second housing.

[0063] Figure 13 For the purpose of illustration Figure 9 The diagram shows the state in which the internal gear moves in a direction perpendicular to the axis and comes into contact with the second housing.

[0064] Figure 14 For the purpose of illustrating when from Figure 12 The diagram shows the contact state between the second housing and the internal gear when observed by arrow XIV.

[0065] Figure 15 To be Figure 11 The diagram shown compares the movement restriction protrusion with another example of a movement restriction protrusion.

[0066] Figure 16 A diagram illustrating an internal gear according to a second embodiment of the present invention.

[0067] Figure 17 This is a cross-sectional view of the second housing according to a second embodiment of the present invention.

[0068] Figure 18 A diagram illustrating an internal gear according to a third embodiment of the present invention.

[0069] Figure 19 A diagram illustrating the state in which the internal gear is housed in the second housing according to a third embodiment of the present invention.

[0070] Figure 20 A diagram illustrating an internal gear according to a fourth embodiment of the present invention.

[0071] Figure 21 A diagram illustrating the state in which the internal gear is housed in the second housing according to a fourth embodiment of the invention.

[0072] Figure 22 A diagram illustrating an internal gear according to a fifth embodiment of the present invention.

[0073] Figure 23 A diagram illustrating the state in which the internal gear is housed in the second housing according to a fifth embodiment of the invention.

[0074] Figure 24 An illustrative diagram is provided to focus on the contact position between the internal gear and the second housing according to a fifth embodiment of the present invention.

[0075] Figure 25 A diagram illustrating an internal gear according to a sixth embodiment of the present invention.

[0076] Figure 26 A diagram illustrating the second housing according to a sixth embodiment of the invention.

[0077] Figure 27 A diagram illustrating the state in which the internal gear is housed in the second housing according to a sixth embodiment of the invention.

[0078] Figure 28 A diagram illustrating an internal gear according to a seventh embodiment of the present invention.

[0079] Figure 29 A diagram illustrating the second housing according to the seventh embodiment of the present invention.

[0080] Figure 30 A diagram illustrating the state in which the internal gear is housed in the second housing according to a seventh embodiment of the present invention.

[0081] Figure 31 A diagram illustrating an internal gear according to an eighth embodiment of the present invention.

[0082] Figure 32 A diagram illustrating the second housing according to the eighth embodiment of the present invention.

[0083] Figure 33 A diagram illustrating the state in which the internal gear is housed in the second housing according to an eighth embodiment of the present invention.

[0084] Figure 34A diagram illustrating an internal gear according to a ninth embodiment of the present invention.

[0085] Figure 35 A diagram illustrating the second housing according to the ninth embodiment of the present invention.

[0086] Figure 36 A diagram illustrating the state in which the internal gear is housed in the second housing according to a ninth embodiment of the present invention. Detailed Implementation

[0087] The following description, with reference to the accompanying drawings, illustrates a structural unit for separating the internal gear and housing, a planetary gear assembly, and an actuator according to a preferred embodiment of the invention. It should be noted that, for ease of understanding, an orthogonal coordinate system is shown in each drawing, wherein the X-axis is parallel to the axial direction of the actuator 1 according to an embodiment of the invention, and the Y and Z axes are perpendicular to the X-axis.

[0088] (Example 1)

[0089] (Structure of Actuator 1)

[0090] like Figure 1 and Figure 2 As shown, actuator 1 includes, for example, a motor 10 and a planetary gear assembly 20 connected to the motor 10.

[0091] Motor 10 has, for example, a motor main unit 11 and a rotating shaft 12, such as Figure 3 and Figure 4 As shown. Under the control of a control unit (not shown), the motor 10 rotates the rotating shaft 12 to drive the planetary gear unit 20.

[0092] Planetary gear unit 20 reduces the speed of the gears from the specified reduction ratio. Figure 1 The motor 10 shown is input to rotation and outputs it to the output gear 86a. The planetary gear unit 20 includes, for example, a housing 50 and a planetary gear mechanism 60 housed within the housing 50, the housing having a first housing 30 and a second housing 40, as... Figure 3 and Figure 4 As shown.

[0093] The first housing 30 is a component used, for example, to attach the motor 10 to the planetary gear mechanism 20. Furthermore, the first housing 30 is assembled with the second housing 40 to form a receiving space S for accommodating the planetary gear mechanism 60, such as... Figure 5 As shown. Figure 4As shown, an opening 30a is formed at the center of the first housing 30, and the rotating shaft 12 of the motor 10 passes through this opening. The rotating shaft 12 passing through the opening 30a is fixed (connected) to the sun gear 71 of the planetary gear mechanism 60, as described below. The first housing 30 is formed by injection molding and is made of, for example, synthetic resin.

[0094] The second housing 40 is open on the side connected to the first housing 30 (“one side”), for example, as Figure 5 and Figure 6 As shown, and Figure 4 The planetary gear mechanism 60 shown can be accommodated in a second housing from this open portion. For example, as... Figure 4 As shown, the planetary gear mechanism 60 has a first planetary gear mechanism 70, a second planetary gear mechanism 80, and an output gear 86a arranged axially. The planetary gear mechanism 60 reduces the (input) rotation generated by the motor 10 in two stages and outputs it from the output gear 86a. For example, as Figure 5 As shown, the second housing 40 has a first position 41 in which the first planetary gear mechanism 70 is accommodated, a second position 42 in which the second planetary gear mechanism 80 is accommodated, and a third position 43 in which the output gear 86a of the second planetary gear mechanism 80 protrudes outward.

[0095] For example, such as Figure 5 and Figure 6 As shown, the first position 41 of the second housing 40 has a cylinder 44 and a stop (second protrusion) 45 extending axially (from one side of the axial direction to the other). When divided by a cross-section perpendicular to the axial direction, the stop 45 has a herringbone-shaped cross-section, wherein its shape and dimensions are constant in the axial direction. The stop 45 is formed axially within a portion of the first position 41, but alternatively, it can be formed over its entire range. For example, as... Figure 9 As shown, the stop members 45 are arranged in pairs along the circumferential direction of the inner wall 44a of the cylinder 44. For example, the pairs of stop members 45 are arranged at six positions on the inner wall 44a of the cylinder 44 at equal intervals. For example, as... Figure 10 As shown, the cross-sectional shape of each stop 45 has an upright portion 45a forming an arc that gradually rises from the inner wall 44a of the cylinder 44, a rounded top 45c, and a connecting portion 45b for connecting the upright portion 45a and the top 45c during bulging. It should be noted that the shape and dimensions of the cross-section of the stop 45 are constant in the axial direction. Therefore, for example, from... Figure 6 It can be understood that the upright part 45a, the connecting part 45b, and the top 45c are curved surfaces that do not bend in a direction parallel to the axis. Figure 9The movement-limiting protrusion 75 of the internal gear 74 shown and described below is inserted between the pairs of stops 45 to limit the movement of the internal gear 74 within the second housing 40.

[0096] For example, such as Figure 5 and Figure 6 As shown, the second position 42 of the second housing 40 has a cylinder 46 and an internal toothed portion 47 formed on the inner wall of the cylinder 46. The internal toothed portion 47 is inclined, for example, at an angle relative to the axial direction. That is, the second position 42 where the internal toothed portion 47 is present is configured, for example, as a helical gear.

[0097] The third position 43 of the second housing 40 is formed, for example, a cylinder, and has an opening 43a through which the output gear 86a of the planetary gear mechanism 60 passes, such as... Figure 4 As shown. The torque output from the output gear 86a can be transmitted to an external mechanism. The second housing 40 is formed by injection molding and is made of, for example, synthetic resin.

[0098] Additionally, for convenience in this instruction manual, Figure 4 to Figure 6 In this design, the side of the second housing 40 that is open for attachment to the first housing 30 is referred to as "one side" (-X direction side), and the side of the second housing 40 with the opening 43a at the third position 43 is referred to as "the other side" (+X direction side), which are opposite sides. However, the invention is not limited thereto, and the side of the second housing 40 with the opening 43a at the third position 43 may be referred to and interpreted as one side, and the side of the second housing 40 that is open for attachment to the first housing 30 may be referred to and interpreted as the other side.

[0099] For example, such as Figure 4 As shown, the planetary gear mechanism 60 is housed within the housing 50 and reduces the rotation transmitted from the motor 10 and outputs it from the output gear 86a. The planetary gear mechanism 60 has, for example, a first planetary gear mechanism 70 and a second planetary gear mechanism 80 arranged axially.

[0100] For example, such as Figure 7 As shown, the first planetary gear mechanism 70 includes: a sun gear 71; three(multiple) planetary gears 72 arranged around the periphery centered on the sun gear 71; a support 73 for rotatably supporting the three(multiple) planetary gears 72; and an internal gear 74. It should be noted that, although for convenience, in... Figure 7 The perspective view shows only two planetary gears 72, but another planetary gear 72 is located on the back side and is blocked by the bracket 73.

[0101] The sun gear 71 is an external gear having a sun tooth portion 71a formed on its outer peripheral surface, and Figure 4The rotating shaft 12 of the motor 10 shown is fixed (connected) to the external gear. In this way, the sun gear 71 rotates by the operation of the motor 10. The sun gear portion 71a has helical teeth that are cut at an angle relative to the axis of the sun gear 71, for example. That is, the sun gear 71 is, for example, a helical gear.

[0102] Planetary gear 72 is, for example, an external gear, wherein planetary tooth portions 72a are formed on its outer peripheral surface. The planetary tooth portions 72a have, for example, helical teeth that are angled relative to the axis of the planetary gear 72. That is, planetary gear 72 is, for example, a helical gear. Three planetary gears 72 are arranged at equal intervals on the same circle centered on the axis of the first planetary gear mechanism 70. A sun gear 71 is positioned between the three planetary gears 72, wherein the sun tooth portion 71a meshes with the corresponding planetary tooth portions 72a of the three planetary gears 72.

[0103] The support 73 is formed, for example, in a cylindrical shape, wherein three receiving openings 73a for receiving the planetary gears 72 are formed in the outer peripheral surface of the support. Each of the planetary gears 72 is rotatably supported within a corresponding receiving opening 73a by an axially facing pin 76, as shown below. Figure 3 As shown. The planetary gear 72 is attached with, for example, a portion of the planetary tooth portion 72a protruding from the outer peripheral surface of the support 73. Thus, the planetary tooth portion 72a can mesh with the internal tooth portion 74a of the internal gear 74, as described below.

[0104] The internal tooth portion 74a is formed on the inner peripheral surface of the internal gear 74, such as, for example... Figure 3 and Figure 7 As shown. The internal gear portion 74a is, for example, a helical gear, which has helical teeth that are angled relative to the axis of the internal gear 74. The rounded diameter of the tooth tips of the internal gear 74 is larger than the diameter of the cylindrical support 73. Therefore, the support 73 holding the planetary gear 72 is accommodated inside the internal gear 74. The planetary gear portion 72a, which protrudes from the outer peripheral surface of the support 73, meshes with the internal gear portion 74a of the internal gear 74.

[0105] Furthermore, a movement-limiting protrusion (first protrusion) 75, which enters the gap between a pair of stoppers 45 formed on, for example, the inner wall 44a of the second housing 40, is formed on the outer peripheral surface of the internal gear 74, such as... Figure 9 As shown. Movement-limiting protrusions 75 are provided corresponding to, for example, pairs of stops 45 formed in six positions, similar to the pairs of stops 45. When divided by a plane perpendicular to the axial direction, the movement-limiting protrusions 75 have a substantially triangular cross-section. Figure 11As shown, the movement-restricting protrusion 75 has, for example, a straight, inclined edge portion 75a rising from the outer peripheral surface 74b of the internal gear 74, and a rounded top 75b positioned at the intersection of the inclined edge portions 75a rising from both sides. It should be noted that, as Figure 7 As shown, the cross-sectional shape and dimensions of the movement-restricting protrusion 75 are constant in the axial direction (having a constant axial extension from one side to the other), and therefore the inclined edge portion 75a of the movement-restricting protrusion 75 constructs a planar region. It should be noted that although the movement-restricting protrusions 75 are formed over the entire width of the internal gear 74, they can alternatively be formed only in a portion of the range of the internal gear. Furthermore, as... Figure 7 As shown, a hemispherical protrusion 74b is formed on the end face of the internal gear 74 on the +X direction side. The hemispherical protrusion 74b is formed in each gap between adjacent movement-limiting protrusions 75, in a total of six positions. When the internal gear 74 is received in the first position 41 of the second housing 40, as... Figure 5 As shown, the tops of the six protrusions 74b will contact the stepped surface 46a. Figure 5 and Figure 6 The stepped surface forms the boundary between the first position 41 and the second position 42 of the second housing 40. Considering that the contact between a spherical surface and a plane is a point contact, the contact between the protrusion 74b and the stepped surface 46a is also a point contact. The internal gear 74 is made of, for example, synthetic resin. It should be noted that, as described below, the internal gear 74 is formed with a hardness ratio... Figure 9 The second shell 40 shown is formed of a synthetic resin with low hardness.

[0106] like Figure 9 As shown, the second housing 40 and the internal gear 74 are physically separated, and a gap is formed between the second gear and the internal gear when the actuator 1 is not operated. Therefore, the internal gear 74 is in a floating state within the second housing 40, allowing rotation about the axial direction and allowing movement within the second housing 40 in a direction perpendicular to the axial direction by an amount corresponding to the gap between the internal gear 74 and the second housing 40. Furthermore, further movement of the internal gear 74 is prevented by a stop 45 formed on the internal gear 74 that restricts contact movement against the protrusion 75.

[0107] The second planetary gear mechanism 80 (which is another planetary gear mechanism) includes, for example, a sun gear 81, three planetary gears 82, a support 83 rotatably supporting the three planetary gears 82, and an output shaft 86, such as Figure 8 As shown. It should be noted that, although for convenience, in Figure 8The perspective view shows only two planetary gears 82, but another planetary gear 82 is located on the back side and is blocked by the bracket 83.

[0108] The sun gear 81 is an external gear, on which the sun tooth portion 81a is formed on, for example, the outer peripheral surface, and is fixed (connected) to the support 73 of the first planetary gear mechanism 70 with the axes aligned together. Figure 7 As shown. Therefore, as the support 73 of the first planetary gear mechanism 70 rotates, the sun gear 81 will rotate in the same direction as the support 73 of the first planetary gear mechanism 70 (linked for synchronization). That is, as the support 73 of the first planetary gear mechanism 70 rotates, the sun gear 81 rotates at the same speed as the support 73 of the first planetary gear mechanism 70 because its direction of rotation is the same as that of the support 73 of the first planetary gear mechanism 70. The sun gear portion 81a has, for example, helical teeth that are angled relative to the axis of the sun gear 81. That is, the sun gear 81 is, for example, a helical gear.

[0109] Planetary gear 82 is, for example, an external gear, wherein planetary tooth portions 82a are formed on its outer peripheral surface. The planetary tooth portions 82a have, for example, helical teeth that are angled relative to the axis of the planetary gear 82. That is, planetary gear 82 is, for example, a helical gear. For example, three planetary gears 82 are arranged at equal intervals on the same circle centered on the axis of the second planetary gear mechanism 80. A sun gear 81 is positioned between the three planetary gears 82, wherein the sun tooth portion 81a meshes with the corresponding planetary tooth portions 82a of the three planetary gears 82. Additionally, the planetary gears 82 mesh with internal tooth portions 47 formed on the second housing 40, such as... Figure 5 and Figure 6 As shown.

[0110] The support 83 has, for example, a gear retaining portion 84 for retaining planetary gears 82 and an output shaft retaining portion 85 for retaining an output shaft 86. The gear retaining portion 84 is formed, for example, in a cylindrical shape, wherein three receiving openings 84a for receiving the planetary gears 82 are formed in the outer peripheral surface of the support. Each of the planetary gears 82 is rotatably attached to a corresponding receiving opening 84a by an axially facing pin 87, as shown below. Figure 3 As shown. The planetary gear 82 is attached with a portion of its planetary tooth portion 82a protruding from the outer peripheral surface of the support 83. This makes it possible for the planetary tooth portion 82a to mesh with the internal tooth portion 47 formed on the second housing 40. Furthermore, as... Figure 8 As shown, the output shaft holding portion 85 is formed as a cylinder with a diameter smaller than that of the gear holding portion 84, and a mounting hole 85a for holding the output shaft 86 is formed in the center portion of the output shaft holding portion 85.

[0111] The output shaft 86 is held, for example, on the bracket 83 and rotates together with the bracket 83. The output shaft 86 has an output gear 86a, which has knurled teeth on the shaft. That is, the output shaft 86 is constructed as a gear, for example, having knurled teeth.

[0112] (Operation of Actuator 1)

[0113] The following will illustrate an example of the operation of actuator 1. First, when Figure 4 When the motor 10 shown is in operation, the rotating shaft 12 rotates in a first direction or a second direction. The following description will focus on the case where the rotating shaft 12 rotates in the first direction.

[0114] It should be noted that, relative to the rotation direction of each component in the structure, the first direction is when rotating from... Figure 1 The arrow AII indicates a clockwise direction when viewing all components. On the other hand, the second direction is the direction of rotation relative to each component within the group, when viewed from... Figure 2 The arrow AII shown indicates the counter-clockwise direction when observing all components.

[0115] When the rotating shaft 12 rotates in the first direction, the sun gear 71 (in) Figure 3 and Figure 7 (As shown in the diagram) it rotates in the first direction as the rotating shaft 12 rotates. As the sun gear 71 rotates in the first direction, the three planetary gears 72 meshing with the sun gear 71 each rotate in the second direction. Furthermore, because the planetary gears 72 mesh with the internal gear 74, they rotate (revolve) about the axis of the first planetary gear mechanism 70 in the first direction by rotating in the second direction. As the planetary gears 72 rotate (revolve), the support 73 rotates in the first direction around its own axis.

[0116] Thus, when the bracket 73 rotates in the first direction, the sun gear 81 fixed by the bracket 73 (in) Figure 3 and Figure 8 (As shown in the diagram) it will rotate in the first direction. As the sun gear 81 rotates in the first direction, the three planetary gears 82 meshing with the sun gear 81 each rotate in the second direction. Furthermore, because the planetary gears 82 mesh with the internal gear portion 47, as... Figure 5 and Figure 6 As shown, they rotate (revolve) about the axis of the second planetary gear mechanism 80 in the first direction by rotating in the second direction. As the planetary gear 82 rotates (revolve) in the first direction, the support 83 rotates about its own axis in the first direction. In view of this, the rotation of the support 83 is transmitted to the output shaft 86 held on the support 83.

[0117] Although the above description describes the case where the rotating shaft 12 rotates in the first direction, the description of the operation of the actuator 1 would be the same if the rotating shaft 12 rotates in the second direction, except that the rotation direction of each gear in the gear is opposite.

[0118] As described above, the second housing 40 and the internal gear 74 are physically separated. Furthermore, when the actuator 1 is not operated, a gap is formed between the second housing 40 and the internal gear 74. Therefore, when the actuator 1 is operated, the internal gear 74 can rotate about the axis of the second housing 40, or move in a direction perpendicular to the axis by an amount equivalent to the provided gap. For example, when the internal gear 74 moves from... Figure 9 When rotating in the first direction (clockwise) as shown, each of the plurality of movement-limiting protrusions 75 formed on the internal gear 74 will soon come into contact with the corresponding stop 45 formed on the second housing 40, as... Figure 12 As shown. Therefore, the internal gear 74 cannot rotate further in the clockwise direction. Because the stop members 45 are formed in pairs, even if the internal gear 74 rotates in the second direction (counterclockwise), the rotation of the internal gear 74 about the axis will be limited by the same line contact.

[0119] In addition, internal gear 74 from Figure 9 The state shown moves in a direction perpendicular to the axis, for example, moving upwards in the diagram. Therefore, as... Figure 13 As shown, the movement-limiting protrusion 75 formed on the upper part of the internal gear 74 makes line contact with the stop 45 formed on the second housing 40. Therefore, the internal gear 74 cannot move further in the upward direction, and its movement in the direction perpendicular to the axis is restricted. Furthermore, in this case, the top 75b of the internal gear 74 (more specifically, the top 75b of the movement-limiting protrusion 75) will not contact the second housing 40 (or more specifically, the inner wall 44a of the cylinder 44). It should be noted that the restriction on the movement of the internal gear 74 in the direction perpendicular to the axis is not limited to the upward movement of the internal gear 74. Because the six movement-limiting protrusions 75 and the stop 45 are arranged at equal intervals in the circumferential direction, they are able to restrict the movement of the internal gear 74 in various directions, such as... Figure 9 The vertical direction, horizontal direction, and diagonal direction.

[0120] (Effect)

[0121] In view of the above implementation scheme, even in a structural unit in which the internal gear 74 and the second housing 40 are separated, the internal gear 74 will move during the operation of the actuator 1, and the stop 45 and the movement limiting protrusion 75 will make line contact, thereby limiting the movement of the internal gear 74. Figure 12The diagram illustrates the line contact state between the internal gear 74 and the second housing 40 due to rotation of the internal gear 74 about its axis. In this case, the stop 45 and the movement-limiting protrusion 75 are in contact in all six positions, and the form of contact is the same in all positions. Therefore, reference will be made to... Figure 12 The enlarged view in the figure illustrates the single contact location at the top of the figure. As shown, the contact location between the connecting portion 45b of the stop 45 (shown by the bulging convex curve) and the inclined edge portion 75a of the movement limiting protrusion 75 (shown by the straight line) can be depicted as contact point P1. That is, this contact will be within a very limited range. It should be noted that the cross-sections of the second housing 40 and the internal gear 74 have constant shapes and dimensions in the axial direction. Therefore, the contact between the connecting portion 45b and the inclined edge portion 75a will be a contact between a convex surface without curvature in the direction parallel to the axis and a plane parallel to the axis. Therefore, the contact between the internal gear 74 and the second housing 40 will be a line contact along the axial direction parallel to the X-axis, and with Figure 14 The contact area shown is the same as 90.

[0122] also, Figure 13 The diagram illustrates the contact state between the second housing 40 and the internal gear 74 via movement of the internal gear 74 in a direction perpendicular to the axis (e.g., upward movement in the figure). Figure 13 As shown, the contact positions between the second housing 40 and the internal gear 74 are indicated by four positions from contact points P2 to P5. Figure 13 As shown in the enlarged view, contact points P2 and P3 are the contact locations between the connecting portion 45b of the stop 45 (shown by the bulging convex curve) and the inclined edge portion 75a of the movement-limiting protrusion 75 (shown by a straight line). In the same manner as described above, such contact locations are line contacts between the two, assumed to be a contact between a convex surface without curvature in the direction parallel to the axis and a plane parallel to the axis. Furthermore, the contact between the stop 45 and the movement-limiting protrusion 75 at contact points P4 and P5 will also be line contacts, as they are contacts between a convex surface and a plane.

[0123] In this way, by providing a pair of herringbone-shaped stoppers 45 (with convex curved surfaces) and configuring them to facilitate the insertion of triangular movement-limiting protrusions 75 (with flat inclined surfaces) therebetween, the contact between the outer peripheral surface of the internal gear 74 and the inner peripheral surface of the second housing 40 can be made into line contact, even when the internal gear 74 has rotated about the axis and even when the internal gear has moved in a direction perpendicular to the axis. Since the contact area between the outer peripheral surface of the internal gear 74 and the inner peripheral surface of the second housing 40 is small (in this way, line contact), the vibration transmitted from the internal gear 74 to the second housing 40 during operation will be reduced. This suppresses the vibration of the second housing 40 generated by the first planetary gear mechanism 70, thereby suppressing the noise generated from the planetary gear unit 20 with the vibration caused by the first planetary gear mechanism 70.

[0124] It should be noted that the term "line contact" as described in this specification refers to a contact state in which the contact portions form a line, and it indicates not only a contact state shown by a single point or multiple points that are contact points in each individual cross-section, but also... Figure 14 As shown, this includes a contact state in which the width W is considered sufficiently small compared to the length L in the contact area 90. Furthermore, the term "line contact" as used in this specification also includes a contact state in which the contact is discontinuous (sporadic contact) such that when an imaginary line is drawn axially, the width W in the contact area 90 will form a line contact state. Furthermore, the term "line contact" as used in this specification also includes a contact state in which the width W in the contact area 90 forms a line described as an angle rather than an axial line. Furthermore, the term "line contact" as used in this specification also includes a contact state in which the contact is discontinuous (sporadic contact) such that when an imaginary line is drawn as an angle rather than axially, the width W in the contact area 90 will form a line contact state. Although the above embodiments describe a form in which the first protrusion and the second protrusion engage in line contact, the invention is not limited thereto. Rather, the contact method may be appropriately selected according to the form and may be a form in which point contact exists or a form in which surface contact exists between the first protrusion and the second protrusion.

[0125] Furthermore, in this embodiment, a hemispherical protrusion 74b is formed on the end face of the internal gear 74 on the +X direction side, where the protrusion 74b contacts the stepped surface 46a of the second housing 40. Figure 5 and Figure 6 The contact between the protrusion 74b and the stepped surface 46a can be maintained within a limited range, i.e., point contact. This reduces vibrations transmitted from the internal gear 74 during operation to the second housing 40.

[0126] In addition, such as Figure 11As shown, the cross-section of the movement-restricting protrusion 75, cut by a plane perpendicular to the axis, is triangular to create an outward-facing top 75b (narrow at the top) that allows the internal gear 74 to be easily removed from the mold during injection molding. This improves yield.

[0127] In addition, such as Figure 15 As shown, in a cross-section taken from a plane perpendicular to the axial direction, the movement-restricting protrusion 75 has straight, inclined edge portions 75a formed on both sides. Furthermore, Figure 15 A motion-limiting protrusion 100 is shown as a reference example of a motion-limiting protrusion 75, the shape of which is indicated by a double-dotted dashed line, wherein both sides are bulging. Comparing the two, the cross-sectional area of ​​the motion-limiting protrusion 75 is reduced by an amount equivalent to the area indicated by the shaded line compared to the cross-sectional area of ​​the motion-limiting protrusion 100. In view of this, this embodiment can reduce the load on the motor 10 by reducing the weight of the internal gear 74, and also reduce manufacturing costs. Furthermore, since the weight of the operating internal gear 74 is reduced, the present invention can reduce (suppress) the impact when the internal gear 74 contacts the second housing 40, thereby also reducing (suppressing) the vibration of the second housing.

[0128] Furthermore, the internal gear 74 is formed of a synthetic resin with a lower hardness than the synthetic resin used to form the second housing 40. From the perspective of mechanical strength, wear resistance, and thermal durability, it is preferable that the synthetic resin used to form the internal gear 74 and the second housing 40 is an engineering plastic or a super engineering plastic. These synthetic resins can be, for example, ultrapolymer polyethylene (UHPE), polyphenylene sulfide (PPS), polyarylate (PAR), polyoxymethylene (POM), polyamide (PA), polycarbonate (PC), polybutylene terephthalate (PBT), polyethersulfone (PES), polyetheretherketone (PEEK), etc.

[0129] The synthetic resins used to form the internal gear 74 and the second housing 40 may be the same material or different materials. They may be suitably selected within the range that produces the effects of the present invention.

[0130] Among the aforementioned synthetic resins, the relatively soft synthetic resin suitable for forming the internal gear 74 is preferably, for example, ultrapolymer polyethylene (UHPE), polyphenylene sulfide (PPS), polyarylate (PAR), polyoxymethylene (POM), or polyamide (PA). Furthermore, the relatively hard synthetic resin suitable for forming the second housing 40 is preferably, for example, polycarbonate (PC), polybutylene terephthalate (PBT), polyethersulfone (PES), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyoxymethylene (POM), or polyamide (PA). Moreover, when synthetic resin materials having the same main components are used for forming the internal gear 74 and the second housing 40, preferably, by changing, for example, the density of the synthetic resin, the synthetic resin used to form the second housing 40 will be harder.

[0131] By forming the internal gear 74 from a synthetic resin with a hardness lower than that of the second housing 40, the impact when the internal gear 74 contacts the second housing 40 can be mitigated, thereby reducing (suppressing) vibrations generated within the second housing 40. In this way, the present invention can reduce (suppress) noise caused by vibrations of the second housing 40, and further reduce (suppress) noise when the internal gear 74 collides with the second housing 40. Therefore, noise generated from the planetary gear assembly 20 due to vibrations caused by the first planetary gear mechanism 70 can be suppressed.

[0132] Furthermore, in this embodiment, the structure in which the housing and internal gear are separated is applied only to the first planetary gear mechanism that rotates at high speed, and not to the second-stage planetary gear mechanism that rotates at low speed. That is, in this embodiment, the structure that allows the internal gear to float is used in mechanisms that rotate at high speed and tend to generate large vibrations and noise, while the housing structure forming the internal gear is used in mechanisms that rotate at low speed, where vibrations and noise tend to be relatively small. In this way, this embodiment not only suppresses the vibration and noise of the planetary gear unit caused by the planetary gear mechanism, but also prevents the number of parts in the planetary gear unit from increasing beyond the necessary number, and prevents an increase in assembly operations and assembly costs. Therefore, it is possible to reduce the manufacturing cost of the planetary gear unit. Thus, depending on the situation, two mechanisms with different structures can be used, specifically depending on the rotational form of the planetary gear mechanism, and these two mechanisms can be used in parallel.

[0133] Other embodiments of the invention will now be described. However, since many of these structures are the same as those in the first embodiment, the following description will focus on the different structures, wherein the same structures are assigned the same reference numerals, and their detailed descriptions will be omitted.

[0134] (Example 2)

[0135] In the second embodiment, the extension direction of the stop pair is formed on the second housing, and the movement-limiting protrusions formed on the internal gear are different from those in the first embodiment. It should be noted that the other structures are the same as in the first embodiment.

[0136] like Figure 16 As shown, six movement-limiting protrusions 275 extending diagonally relative to the X-axis are formed at equal intervals on the outer peripheral surface of the internal gear 274. All six movement-limiting protrusions 275 are tilted at the same angle relative to the X-axis. When cut by a plane perpendicular to their extension direction (the direction of tilt relative to the X-axis), the cross-section of the movement-limiting protrusions 275 is similar to that of the first embodiment (…). Figure 7 The movement-restricting protrusion 75 is cut by a plane perpendicular to its extension direction (X-axis) with the same cross-section. That is, the movement-restricting protrusion 275 has a triangular cross-section, such as... Figure 11 As shown.

[0137] The movement restriction protrusion 275 formed on the internal gear 274 is inserted into the gear formed on the internal gear 274. Figure 17 The pair of stops 245 are located at the first position 241 of the second housing 240 shown. The direction in which the pair of stops 245 extends is the same as the direction in which the movement-limiting protrusion 275 of the internal gear 274 housed in the second housing 240 extends, which is an inclined direction relative to the X-axis. When cut by a plane perpendicular to its extending direction (the inclined direction relative to the X-axis), the cross-section of the pair of stops 245 is consistent with that of the first embodiment ( Figure 6 The stop 45 has the same cross-section taken from a plane perpendicular to its extension direction (X-axis). That is, the stop 245 has a herringbone-shaped cross-section, such as... Figure 10 As shown.

[0138] Thus, the cross-sectional shapes of the movement-limiting protrusion 275 and the stop 245 are the same as in the first embodiment, resulting in a line contact between them. Furthermore, the contact between the movement-limiting protrusion 275 and the stop 245 pair will be a line contact in a direction inclined relative to the X-axis. In this way, the contact area between the movement-limiting protrusion 275 and the stop 245 pair (through line contact) reduces vibration transmitted from the internal gear 274 to the second housing 240 during operation. This suppresses vibration of the second housing 240, and consequently suppresses noise generated from the planetary gear assembly.

[0139] Furthermore, there is no specific limitation on the tilt angle of the movement limiting protrusion 275 and the stop 245 relative to the X-axis. This tilt angle can be the same as the angle of the teeth if the internal gear is, for example, a helical gear, or it can be tilted at the opposite angle to the angle of the teeth, or it can be tilted at some different angles. The tilt angle of the movement limiting protrusion 275 and the stop 245 being the same as the angle of the helical gear of the internal gear can reduce the thrust generated within the planetary gear assembly.

[0140] (Example 3)

[0141] Next, we will refer to Figure 18 and Figure 19 The third embodiment is described below. In the third embodiment, the number of stop pairs formed on the second housing and the number of movement-limiting protrusions formed on the internal gear are set to 3, which is half the number in the first embodiment, in which each of them is formed to six.

[0142] like Figure 18 As shown, three movement-limiting protrusions 375 extending in the X-axis are formed at equal intervals on the outer peripheral surface of the internal gear 374. The cross-section of the movement-limiting protrusions 375 is the same shape as the cross-section of the movement-limiting protrusion 75 in the first embodiment (the latter has a triangular cross-sectional shape, such as...). Figure 11 (As shown). Three arcuate portions 376 are formed on the outer peripheral surface of the internal gear 374 between the movement-restricting protrusions 375. An arcuate opening 376a is formed on the inner side of each of the three arcuate portions 376, which passes through the internal gear 374 in the X-axis direction. The three arcuate portions 376 serve as contact portions that contact the inner wall 344a of the second housing 340.

[0143] like Figure 19 As shown, three pairs of stops 345 are also formed at equal intervals on the inner wall 344a of the second housing 340, and they are inserted between the movement-limiting protrusions 375. The cross-section of the pairs of stops 345 has the same shape as the cross-section of the pairs of stops 45 in the first embodiment (the latter has a herringbone cross-sectional shape, such as...). Figure 10(As shown). Note that when the internal gear 374 moves within the second housing 340, the movement-limiting protrusion 375 and the stop 345 make line contact, thereby limiting the movement of the internal gear 374. Additionally, the movement of the internal gear 374 is limited by the arcuate portion 376 contacting the inner wall 344a of the second housing 340. The arcuate portion 376 and the inner wall 344a make surface contact. However, the formation of the opening 376a creates a component in which vibrations do not propagate within the internal gear 374 and also reduces the stiffness of the arcuate portion 376. This allows for reduced vibration transmission to the second housing 340 via the arcuate portion 376. This suppresses noise generated from the planetary gear assembly by inhibiting vibration transmission to the second housing 340, even when the internal gear 374 contacts the second housing 340 via the movement-limiting protrusion 375 and even when the internal gear contacts the second housing 340 via the arcuate portion 376. It should be noted that the protrusion may be configured to protrude on the outer side of the arcuate portion 376 to contact the inner wall 344a of the second housing 340. This allows the contact area between the arcuate portion 376 and the second housing 340 to be limited to a narrow range.

[0144] (Example 4)

[0145] Next, we will refer to Figure 20 and Figure 21 Explain the fourth implementation plan. For example... Figure 20 As shown, three movement-limiting protrusions 475 extending in the X-axis are formed at equal intervals on the outer peripheral surface of the internal gear 474. Each movement-limiting protrusion 475 has a triangular cross-section with a top 475b and inclined edge portions 475a formed on both sides of the top 475b. Three arcuate portions 476 forming the outer peripheral surface of the internal gear 474 are formed between the movement-limiting protrusions 475. These three arcuate portions 476 are more... Figure 19 The arc-shaped portion 376 of the third embodiment shown is formed in a state where it is pulled further toward the axis side (inner side).

[0146] like Figure 21 As shown, three pairs of stops 445 are also formed at equal intervals on the inner wall 444a of the second housing 440, and they are inserted between the movement-limiting protrusions 475. The cross-section of the pairs of stops 445 has the same shape as the cross-section of the pairs of stops 45 in the first embodiment (the latter has a herringbone cross-sectional shape, such as...). Figure 10(As shown). Note that when the internal gear 474 moves within the second housing 440, the movement-limiting protrusion 475 and the stop 445 make line contact, thereby limiting the movement of the internal gear 474. On the other hand, the arcuate portion 476 is formed in the state described above, pulled towards the axial side (inner side), and therefore does not contact the inner wall 444a of the second housing 440. In this way, the number of contact positions between the movement-limiting protrusion 475 and the stop 445 is reduced to three, and line contact is made between them, making it possible to reduce the contact area compared to the above form, thereby reducing the transmission of vibration from the operating internal gear 474 to the second housing 440. This suppresses the vibration of the second housing 440, and in turn, suppresses the noise generated from the planetary gear device.

[0147] (Example 5)

[0148] Next, we will refer to Figure 22 to Figure 24 Explain the fifth implementation plan. For example... Figure 22 As shown, three movement-limiting protrusions 575 extending in the X-axis are formed at equal intervals on the outer peripheral surface of the internal gear 574. The movement-limiting protrusions 575 have an outwardly bulging herringbone shape. Three arcuate portions 576 forming the outer peripheral surface of the internal gear 574 are formed between the movement-limiting protrusions 575. These three arcuate portions 576 are designed to conform to the... Figure 21 The arc-shaped portion 476 of the fourth embodiment shown is formed in the same manner as being pulled toward the axis side (inner side).

[0149] like Figure 23 As shown, three pairs of stops 545 are also formed at equal intervals on the inner wall 544a of the second housing 540, and they are inserted between the movement-limiting protrusions 575. The cross-section of the pairs of stops 545 has the same shape as the cross-section of the pairs of stops 45 in the first embodiment (the latter has a herringbone cross-sectional shape, such as...). Figure 10 (As shown). Note that when the internal gear 574 moves within the second housing 540, the movement limiting protrusion 575 and the stop 545 come into contact, thereby limiting the movement of the internal gear 574.

[0150] This will be referenced Figure 24 This illustrates the contact between each of the movement-limiting protrusions 575, which has a herringbone cross-sectional shape, and the stop 545. Figure 24In the diagram, when the actuator is not in operation, the internal gear 574 is indicated by a solid line. Furthermore, the internal gear 574, shown by a double-dotted dashed line, is in a state where it has moved upwards to contact the second housing 540 due to the operation of the actuator. The contact between the pair of stops 545 and the movement-limiting protrusion 575 is a contact between convex surfaces, therefore, there will be line contact at contact points P6 and P7 between the pair of stops 545 and the movement-limiting protrusion 575. On the other hand, the arcuate portion 576 is formed in a state pulled towards the axial side (inner side) as described above, and therefore does not contact the inner wall 544a of the second housing 540. Thus, the contact area between the movement-limiting protrusion 575 and the pair of stops 545 (contacting via line contact) reduces the transmission of vibration from the internal gear 574 to the second housing 540 during operation. This suppresses vibration of the second housing 540, and consequently suppresses noise generated from the planetary gear assembly.

[0151] (Example 6)

[0152] Next, we will refer to Figure 25 to Figure 27 Explain the sixth implementation plan. For example... Figure 25 As shown, multiple movement-restricting protrusions 675, formed from an external tooth structure cut along the X-axis, are formed at equal intervals on the outer peripheral surface of the internal gear 674. The movement-restricting protrusions 675 have a substantially trapezoidal cross-sectional shape.

[0153] like Figure 26 As shown, it is inserted into the movement restriction protrusion 675 ( Figure 25 Multiple stops 645 are formed by internal teeth cut along the X-axis from the inner wall 644a of the second housing 640. The stops 645 have a substantially trapezoidal cross-sectional shape. Note that, as... Figure 27 As shown, the internal gear 674 is housed within the second housing 640, and when the internal gear 674 moves from this state, multiple movement-limiting protrusions 675 contact multiple stops 645. The movement of the internal gear 674 is thus restricted. It should be noted that the movement-limiting protrusions 675 and the stops 645 are formed in more locations than in the configuration described above. Therefore, although the movement-limiting protrusions 675 and the stops 645 contact in many locations, each individual contact location is limited to a narrow range. This reduces the propagation of vibrations from the internal gear 674 to the second housing 640 during operation. This suppresses vibrations in the second housing 640, and consequently suppresses noise generated from the planetary gear assembly.

[0154] Furthermore, the external teeth formed on the outer peripheral surface of the internal gear 674 are not limited to external teeth that cut along the X-axis, but may be external teeth that cut in a direction inclined relative to the X-axis. The internal teeth formed on the inner wall 644a of the second housing 640 are not limited to internal teeth that cut along the X-axis, but may be internal teeth that cut in a direction inclined relative to the X-axis.

[0155] If the external teeth formed on the outer peripheral surface of the internal gear 674 and the internal teeth formed on the inner wall 644a of the second housing 640 cut in a direction inclined relative to the X-axis, there is no particular limitation on their angle, and for example, if the internal gear is a helical gear, the inclination can be the same angle as the tooth angle, or the inclination can be the opposite angle to the tooth angle, or it can be some different angles.

[0156] If the angles of the external teeth formed on the outer peripheral surface of the internal gear 674 and the internal teeth formed on the inner wall 644a of the second housing 640 are the same as the angles of the helical gear of the internal gear, this can reduce the amount of thrust generated in the planetary gear assembly.

[0157] (Example 7)

[0158] Next, we will refer to Figure 28 to Figure 30 The seventh embodiment is described below. In the seventh embodiment, the positions of the stop pair and the movement limiting protrusion are interchanged, wherein the movement limiting protrusion is disposed on the inner peripheral surface of the second housing, and the stop pair is disposed on the outer peripheral surface of the internal gear.

[0159] like Figure 28 As shown, six stops 745 extending in the X-axis are formed at equal intervals on the outer peripheral surface of the internal gear 774. The cross-section of the pair of stops 745 has the same shape as the cross-section of the pair of stops 45 in the first embodiment (the latter has a herringbone cross-sectional shape, such as...). Figure 10 (As shown). Figure 29 The movement-restricting protrusion 775 formed on the second housing 740 is inserted between the pairs of stops 745.

[0160] like Figure 29 As shown, six movement-restricting protrusions 775 extending in the X-axis are formed at equal intervals on the second housing 740. The cross-section of the movement-restricting protrusions 775 is the same shape as the cross-section of the movement-restricting protrusions 75 in the first embodiment (the latter has a triangular cross-sectional shape, such as...). Figure 11 (As shown). Note that, as Figure 30 As shown, the internal gear 774 is housed within the second housing 740, and when the internal gear 774 moves from this state, a plurality of movement-limiting protrusions 775 contact a pair of stops 745, thereby limiting the movement of the internal gear 774. At this time, the contact between the movement-limiting protrusions 775 and the pair of stops 745 can be a line contact, the same as the contact form in the first embodiment. Therefore, the propagation of vibrations from the internal gear 774 to the second housing 740 during operation is reduced. This suppresses vibrations in the second housing 740, and consequently suppresses noise generated from the planetary gear assembly.

[0161] (Example 8)

[0162] Next, we will refer to Figure 31 to Figure 33 The eighth embodiment is described below. In the eighth embodiment, the stop pair and the movement-limiting protrusion are arranged with unequal spacing, rather than equal spacing.

[0163] like Figure 31 As shown, three movement-limiting protrusions 875 extending in the X-axis are formed on the outer peripheral surface of the internal gear 874. The movement-limiting protrusions 875 are arranged at unequal intervals. The cross-section of the movement-limiting protrusions 875 is the same shape as the cross-section of the movement-limiting protrusion 75 in the first embodiment (the latter has a triangular cross-sectional shape, such as...). Figure 11 (As shown).

[0164] like Figure 32 As shown, three pairs of stops 845 are also formed at unequal intervals on the inner wall 844a of the second housing 840, and they are inserted between the movement-limiting protrusions 875. The cross-section of the pairs of stops 845 has the same shape as the cross-section of the pairs of stops 45 in the first embodiment (the latter has a herringbone cross-sectional shape, such as...). Figure 10 (As shown). Note that, as Figure 33 As shown, the internal gear 874 is housed within the second housing 840, and when the internal gear 874 moves from this state, a plurality of movement-limiting protrusions 875 contact a pair of stops 845, thereby limiting the movement of the internal gear 874. At this time, the contact between the movement-limiting protrusions 875 and the pair of stops 845 can be a line contact, the same as the contact form in the first embodiment. Therefore, the propagation of vibration from the internal gear 874 to the second housing 840 during operation is reduced. This suppresses vibration of the second housing 840, and consequently suppresses noise generated from the planetary gear assembly.

[0165] Notice, Figure 18 The arcuate portion 376 shown can be formed at a location where the arrangement of the movable limiting protrusion 875 and the stop 845 is spaced unequally. This allows for restriction of movement of the internal gear 874 while suppressing the transmission of vibrations from the internal gear 874.

[0166] (Example 9)

[0167] Next, we will refer to Figure 34 to Figure 36 The ninth embodiment is described below. In the ninth embodiment, the stop that contacts the movement restriction protrusion is arranged in a one-to-one relationship with the movement restriction protrusion, rather than in pairs.

[0168] like Figure 34As shown, six movement-limiting protrusions 975 extending in the X-axis are formed at equal intervals on the outer peripheral surface of the internal gear 974. The cross-section of the movement-limiting protrusions 975 is the same shape as the cross-section of the movement-limiting protrusion 75 in the first embodiment (the latter has a triangular cross-sectional shape, such as...). Figure 11 (As shown).

[0169] like Figure 35 As shown, three first stops 945a and three second stops 945b with equal spacing are formed on the inner wall 344a of the second housing 340. The positions where the first stops 945a and the positions where the second stops 945b are arranged are offset from each other in the circumferential direction. The cross-sections of the first stops 945a and the second stops 945b have the same shape as the cross-sections of the pair of stops 45 in the first embodiment (the latter has a herringbone cross-sectional shape, such as...). Figure 10 (As shown).

[0170] It should be noted that, such as Figure 36 As shown, when the internal gear 974 is housed within the second housing 940, the first stop 945a is provided on one side of the nearest movement limiting protrusion 975. Conversely, the second stop 945b is provided on the other side of the nearest movement limiting protrusion 975. Here, the description is as follows: Figure 36 An example of an upwardly protruding movement-limiting protrusion 975, wherein "one side" refers to the left side of the movement-limiting protrusion 975 in the figure, i.e., the side where the first stop 945a is provided. Furthermore, "the other side" refers to the right side of the upwardly protruding movement-limiting protrusion 975 in the figure.

[0171] When internal gear 974 from Figure 36 When the internal gear 974 rotates counterclockwise (second direction) as shown in the figure, the movement limiting protrusion 975 contacts the first stop 945a, thereby limiting the rotation of the internal gear 974. Additionally, when the internal gear 974 rotates clockwise (first direction) as shown in the figure, the movement limiting protrusion 975 contacts the second stop 945b, thereby limiting the rotation of the internal gear 974. Furthermore, when the internal gear 974 moves radially, the movement limiting protrusion 975 contacts the first stop 945a and the second stop 945b, thereby limiting the movement of the internal gear 974. This contact between the movement limiting protrusion 975 and the first stop 945a and the second stop 945b can be a line contact, the same as the contact form in the first embodiment. Therefore, the propagation of vibration from the internal gear 974 to the second housing 940 during operation is reduced. This suppresses vibration of the second housing 940, and consequently suppresses noise generated from the planetary gear assembly.

[0172] (Modified Implementation Example)

[0173] The present invention is not limited to the above embodiments, but can be modified and applied in various ways. Although in the above embodiments, the cross-section of the pair of stops 45 is herringbone and the cross-section of the movement limiting protrusion 75 is triangular, these cross-sectional shapes can be changed so that the cross-section of the pair of stops is triangular and the cross-section of the movement limiting protrusion inserted between the stops is herringbone.

[0174] Furthermore, there is no specific limitation on the number of locations where the 45 pairs of stops and the corresponding movement-limiting protrusions 75 are provided; this number can be a larger or smaller number than the six locations given in the above embodiment. When the number of locations is small, it can provide... Figure 18 The arc-shaped portion 376 shown is to supplement its function. This allows for stable orientation of the internal gear during operation, thereby enabling the suppression of noise generated from the planetary gear mechanism.

[0175] Furthermore, there are no limitations on this, where line contact can be achieved through a second housing 40 with a locally concave component of high curvature and an internal gear 74 with a convex surface of lower curvature, wherein the concave surface with high curvature contacts the bulging convex surface. The actual structure used to achieve line contact is arbitrary.

[0176] It should be noted that in another example used to achieve the above-mentioned line contact, the configuration of the internal gear in the position of making line contact can be interchanged with the configuration of the second housing.

[0177] Furthermore, although the actuator 1 is provided with a two-stage planetary gear mechanism consisting of a first planetary gear mechanism 70 and a second planetary gear mechanism 80, the number of stages can be arbitrarily set as a speed reduction mechanism for reducing the rotation of the motor 10. For example, the reduction ratio can be increased by providing a three-stage or more planetary gear mechanism, or the structure may include only a single-stage planetary gear mechanism.

[0178] Furthermore, in the above embodiments, a configuration is used in which the housing and internal gear separation structure is applied only to the first planetary gear mechanism 70, which is a first-stage mechanism rotating at high speed, and the housing with internal teeth formed on its inner peripheral surface is used in the second planetary gear mechanism 80, which is a second-stage mechanism rotating at low speed. However, the housing and internal gear separation structure can also be used in the second planetary gear mechanism 80 as a second-stage mechanism to reduce vibration and noise.

[0179] Furthermore, although the above embodiment is described in relation to the case where the reduction gear is used to reduce the rotation of the motor 10 and output it from the output gear 86a, this application is not limited thereto. For example,Figure 8 The component shown, equipped with an output shaft 86, can be used as an input side and connected to the rotating shaft of the motor. Figure 7 The component shown, equipped with the sun gear 71, can be used as the output side and is connected to the output shaft. This increases and outputs the rotation of the motor, serving as a speed-increasing mechanism. In this case, due to... Figure 7 The high-speed operation of the first planetary gear mechanism 70 shown is also preferably achieved using a structure in which the internal gear and housing are separated. Furthermore, since the rotation of the motor is directly transmitted to… Figure 8 The second planetary gear mechanism 80 shown is therefore preferably configured such that the internal gear and housing are separated, as needed. Furthermore, the invention can also be applied to industrial equipment such as robots and machine tools, as well as to amusement park equipment such as so-called "tumbler machines".

[0180] When this invention is used in various applications, when the planetary gear mechanism is provided in three or more stages, a structural unit for separating the internal gear and the housing is applied to the planetary gear mechanism operating at the highest speed. This effectively reduces the resulting vibration and noise. Furthermore, since the vibration and noise generated by the planetary gear mechanism operating at the lowest speed are minimal, a structure equipped with a housing in which the internal teeth are formed on the inner peripheral surface is applied. This eliminates the need for an unnecessary structure for separating the internal gear and the housing, thereby avoiding an increase in the number of parts and an increase in assembly operations and costs, and thus suppressing production costs.

[0181] Furthermore, although the embodiments described above are for the case where each gear in the gears used to transmit power from motor 10 to output shaft 86 is a helical gear, other gears may be used instead. For example, spur gears may be used. Although spur gears tend to produce a larger clearance at the meshing position compared to the case of using helical gears, the structure of the present invention can still be used to reduce (suppress) vibration and noise of the planetary gear unit even in this case.

[0182] Furthermore, although the description pertains to a case where the separate structural unit for the internal gear and the housing is used as part of a planetary gear mechanism, this application is not limited to this, but can be used as part of another gear mechanism.

[0183] In the above embodiments, the planetary gear mechanism of the planetary gear device is implemented using three planetary gears; however, the present invention is not limited thereto. In the present invention, the planetary gear device can be implemented by using a planetary gear mechanism having, for example, a single planetary gear or multiple (other than three) planetary gears.

[0184] Furthermore, the planetary gear device of the present invention can be applied to a variety of machines and equipment that use speed reduction or speed increase mechanisms, such as automobiles, robots, industrial equipment, amusement park equipment, etc.

[0185] Furthermore, instead of the structure described above that restricts movement within the housing by creating an axial line contact between the movement-restricting protrusion (first protrusion) and the stop pair (second protrusion), the structure can be a structure in which movement within the housing is restricted by point contact between the movement-restricting protrusion (first protrusion) and the stop pair (second protrusion). More specifically, Figure 5 The stop pair (second protrusion) 45 may have a discontinuous shape in the axial direction (having multiple gaps), and Figure 7 The movement-restricting protrusion (first protrusion) 75 may have a shape that is discontinuous in the axial direction (with multiple gaps).

[0186] This invention may have various embodiments or modifications without departing from the broad spirit and scope of the invention. Furthermore, the above embodiments are intended to illustrate the invention and do not limit its scope. That is, the scope of the invention is defined by the claims, not by the embodiments. Therefore, various modifications within the patent claims or within the broad scope of the invention's equivalents are considered to be within the scope of the invention.

[0187] [List of Labels in the Attached Image]

[0188] 1: Actuator

[0189] 10: Motor

[0190] 11: Motor main unit

[0191] 12: Rotation axis

[0192] 20: Planetary gear mechanism

[0193] 30: First shell

[0194] 30a: Open

[0195] 40: Second shell

[0196] 41: First position

[0197] 42: Second position

[0198] 43: Third position

[0199] 43a: Opening

[0200] 44: Cylinder

[0201] 44a: Inner wall

[0202] 45: Stop (second protruding part)

[0203] 45a: Upright part

[0204] 45b: Connection part

[0205] 45c: Top

[0206] 46: Cylinder

[0207] 47: Internal teeth section

[0208] 50: Casing

[0209] 60: Planetary gear mechanism

[0210] 70: First planetary gear mechanism

[0211] 71: Sun Gear

[0212] 71a: Sun tooth portion

[0213] 72: Planetary Gears

[0214] 72a: Planetary tooth section

[0215] 73: Stent

[0216] 73a: Accommodation opening

[0217] 74: Internal gear

[0218] 74a: Internal teeth section

[0219] 74b: Outer peripheral surface

[0220] 75: Movement restriction protrusion (first protrusion)

[0221] 75a: Sloping edge portion

[0222] 75b: Top

[0223] 75c: Notch portion

[0224] 76: Sales

[0225] 80: Second planetary gear mechanism

[0226] 81: Sun Gear

[0227] 81a: Sun tooth portion

[0228] 82: Planetary Gear

[0229] 82a: Planetary tooth section

[0230] 83: Bracket

[0231] 84: Gear retaining part

[0232] 84a: Accommodation opening

[0233] 85: Output shaft holding section

[0234] 85a: Assembly hole

[0235] 86: Output shaft

[0236] 86a: Output gear

[0237] 87: Sales

[0238] 90: Contact Area

[0239] 140: Second shell

[0240] 141: Concave component

[0241] 174: Internal gear

[0242] 175: Movement restriction protrusion (first protrusion)

[0243] 240, 340, 440, 540, 640, 740, 840, 940: Second shell

[0244] 245, 345, 445, 545, 645, 745, 845: Stop components

[0245] 274, 374, 474, 574, 674, 774, 874, 974: Internal gears

[0246] 275, 375, 475, 575, 675, 775, 875, 975: Movement restriction protrusions

[0247] 376: Curved section

[0248] 376a: Opening

[0249] 475a: Sloping edge portion

[0250] 475b: Top

[0251] 476: Curved section

[0252] 576: Curved section

[0253] 945a: First stop

[0254] 945b: Second stop

Claims

1. An apparatus for suppressing noise generated in a planetary gear device, characterized by, The apparatus comprises: an internal gear having a first protrusion portion formed on an outer peripheral surface of the internal gear, the first protrusion portion extending in an axial direction from one side of the internal gear to the other side of the internal gear, wherein the first protrusion portion is formed in a first direction inclined with respect to the axial direction; and a housing having a second protrusion portion formed on an inner peripheral surface of the housing, the second protrusion portion extending in a second direction inclined with respect to the axial direction, wherein the second direction corresponds to the first direction such that the first protrusion portion and the second protrusion portion are not parallel with respect to the axial direction; wherein the housing is configured to accommodate the internal gear inside the housing such that the internal gear is a floating internal gear, and a gap is provided between the inner peripheral surface of the housing and the outer peripheral surface of the internal gear, and wherein movement of the internal gear inside the housing is limited by two independent line contacts between the first protrusion portion and the second protrusion portion.

2. An apparatus for suppressing noise generated in a planetary gear device, characterized by, The apparatus comprises: an internal gear having a plurality of first protrusion portions and a contact portion between adjacent first protrusion portions, wherein the plurality of first protrusion portions and the contact portion are each formed on an outer peripheral surface of the internal gear and extend in a direction; and a housing having a second protrusion portion formed on an inner peripheral surface of the housing, the second protrusion portion extending in the direction, wherein the direction is inclined with respect to an axial direction such that the first protrusion portion and the second protrusion portion are not parallel with respect to the axial direction; wherein the housing is configured to accommodate the internal gear such that the internal gear is a floating internal gear, and a gap is provided between the inner peripheral surface of the housing and the outer peripheral surface of the internal gear, wherein movement of the internal gear inside the housing is limited by two independent line contacts of the first protrusion portion and the second protrusion portion, and by contact of the contact portion and the inner peripheral surface of the housing, and wherein an opening is formed inside the contact portion of the internal gear, the opening facing an axial direction of the internal gear.

3. An apparatus for suppressing noise generated in a planetary gear device, characterized by, The apparatus comprises: an internal gear having a plurality of first protrusion portions formed on an outer peripheral surface of the internal gear, each of the plurality of first protrusion portions extending in a direction; and a housing having a plurality of second protrusion portions formed on an inner peripheral surface of the housing, each of the plurality of second protrusion portions extending in the direction, wherein the direction is inclined with respect to an axial direction such that the first protrusion portions and the second protrusion portions are not parallel with respect to the axial direction; wherein the housing is configured to accommodate the internal gear such that the internal gear is a floating internal gear, and a gap is formed between the inner peripheral surface and the outer peripheral surface, wherein movement of the ring gear within the housing is limited by two independent line contacts of the first protrusion and a corresponding second protrusion; and wherein the plurality of first protrusions and the plurality of second protrusions are respectively spaced substantially equidistantly around the ring gear and the housing.

4. An apparatus for suppressing noise generated in a planetary gear device, characterized by, The apparatus comprises: a ring gear having a plurality of first protrusions formed on an outer peripheral surface of the ring gear and extending in a direction; and a housing having a plurality of second protrusions formed on an inner peripheral surface of the housing, the second protrusions extending in the direction, wherein the direction is inclined with respect to an axial direction such that the first protrusions and the second protrusions are not parallel with respect to the axial direction; wherein the housing is configured to accommodate the ring gear such that the ring gear is a floating ring gear, with a gap provided between the inner peripheral surface and the outer peripheral surface, wherein movement of the ring gear within the housing is limited by two independent line contacts of the first protrusion and a corresponding second protrusion, and wherein the plurality of first protrusions and the plurality of second protrusions are respectively spaced non-equidistantly around the ring gear and the housing.

5. The apparatus of any one of claims 1 to 4, wherein, one of the first protrusions and the second protrusions is formed in pairs with a spacing between the pairs of the one of the first protrusions and the second protrusions, and the other of the first protrusions and the second protrusions is provided to be inserted between the pairs of the one of the first protrusions and the second protrusions, and wherein a surface on the one of the first protrusions and the second protrusions that contacts a surface on the other of the first protrusions and the second protrusions is a curved surface.

6. The apparatus of claim 5, wherein, the second protrusions are formed in pairs with the spacing between the pairs of the second protrusions, and the first protrusions are provided to be inserted between the pairs of the second protrusions, and wherein the first protrusions have a triangular cross-section when taken by a plane perpendicular to the axial direction, and contact the second protrusions at inclined surfaces formed in the plane.

7. The apparatus of claim 5, wherein, the first protrusions are formed in pairs with the spacing between the pairs of the first protrusions, wherein the second protrusions are provided to be inserted between the pairs of the first protrusions, and wherein the second protrusions have a triangular cross-section when taken by a plane perpendicular to the axial direction, and contact the first protrusions at inclined surfaces formed in the plane.

8. The apparatus of any one of claims 1 to 4, wherein, a surface of one of the first protrusions and the second protrusions is a convex curved surface, and a surface of the other of the first protrusions and the second protrusions is a flat surface at a contact position between the first protrusions and the second protrusions.

9. The apparatus of any one of claims 1 to 4, wherein, a surface of the first protrusions and a surface of the second protrusions are convex curved surfaces at a contact position between the first protrusions and the second protrusions.

10. The apparatus of any one of claims 1 to 4, wherein, At a contact position between the first protruding portion and the second protruding portion, a surface of one of the first protruding portion and the second protruding portion is a convex curved surface, and a surface of the other of the first protruding portion and the second protruding portion is a concave curved surface.

11. The apparatus of any one of claims 1 to 4, wherein, The first protruding portion includes external teeth cut in the axial direction or external teeth cut in a direction inclined with respect to the axial direction, and The second protruding portion includes internal teeth cut in the axial direction or internal teeth cut in a direction inclined with respect to the axial direction.

12. The apparatus of claim 3 or 4, wherein, A respective second protruding portion is provided for each of the plurality of first protruding portions, wherein one of the plurality of second protruding portions is in contact with the respective first protruding portion when the internal gear rotates in a first direction, and a different one of the plurality of second protruding portions is in contact with the respective first protruding portion when the internal gear rotates in a second direction.

13. The apparatus of any one of claims 1 to 4, wherein, The internal gear and the housing are made of synthetic resin, and The internal gear is made of synthetic resin having a hardness smaller than a hardness of the synthetic resin used to form the housing.

14. A planetary gear device characterized by comprising: The apparatus includes: The apparatus for suppressing noise generated in a planetary gear device according to any one of claims 1 to 13; at least one planetary gear engaged with the internal gear; a sun gear engaged with the one or more planetary gears and located at the center of the one or more planetary gears; and a carrier rotatably supporting the one or more planetary gears.

15. A planetary gear arrangement according to claim 14, characterised in that, The apparatus further includes: a second sun gear rotating similarly to the rotation of the carrier as the carrier rotates; one or more second planetary gears provided on the periphery of the second sun gear and engaged with the second sun gear; a second carrier rotatably supporting the one or more second planetary gears; and a second housing having an internal gear engaged with the one or more second planetary gears formed on an inner peripheral surface of the second housing, wherein the housing and the second housing are integrally formed.

16. A planetary gear arrangement, characterized by The apparatus includes: at least two stages of planetary gear mechanisms, each stage of planetary gear mechanisms including: a sun gear; one or more planetary gears arranged on the periphery of the sun gear for engagement with the sun gear; and a carrier rotatably supporting the one or more planetary gears, wherein, among the at least two stages of planetary gear mechanisms, the planetary gear mechanism operating at a higher speed includes the apparatus for suppressing noise generated in a planetary gear device according to any one of claims 1 to 13, wherein the one or more planetary gears of the planetary gear mechanism and the internal gear are engaged, and wherein the one or more planetary gears of the planetary gear mechanism and the internal gear are engaged, and wherein in the at least two stage planetary gear mechanism, the planetary gear mechanism operating at a lower speed comprises a second housing, wherein an internal toothing engaging with the one or more planetary gears of the planetary gear mechanism is formed on an inner peripheral surface of the second housing.

17. An actuator, characterized by The actuator comprises: a planetary gear device according to any one of claims 14 to 16; and a motor connected to the planetary gear device for driving the planetary gear device.

Images