Actuator and planetary gear device with uneven crowning

Abstract

Actuators, planetary gear devices, and structural unit embodiments configured to reduce noise and vibration caused by operation of a planetary gear are disclosed herein. One embodiment can include a ring gear having an outer peripheral surface extending in an axial direction. A first protruding portion can be formed on the outer peripheral surface; and a housing having an inner peripheral surface disposed facing the outer peripheral surface of the ring gear with a gap therebetween. A second protruding portion can be formed on the inner peripheral surface. Movement of the ring gear in a circumferential direction is limited, for example, by linear contact or point contact between the first and second protruding portions. According to some further embodiments, the outer peripheral surface and / or the inner peripheral surface can be a convexly shaped surface that is curved in an outer radial direction.

Description

Technical Field

[0001] The present disclosure relates to a structural unit, a planetary gear arrangement and an actuator. Background Art

[0002] Planetary gears are used as speed reduction mechanisms in various technologies, such as automobiles and robots, to reduce and output input rotation. Because planetary gears are constructed using a combination of multiple gears, they generate noise and vibration during operation. Technologies have been proposed to suppress the noise and vibration generated during the operation of such planetary gears.

[0003] As a technology proposed in this regard, Patent Document 1 (cited below) discloses a planetary gear device configured to have a gap between the ring gear and the housing to separate them. Using a structure in which the ring gear and the housing are separated results in less vibration being transmitted from the ring gear to the housing, resulting in less noise being generated by the vibration.

[0004] Cited References

[0005] [Patent Document 1] Japanese Examined Patent Application Publication No. H06-074835 Summary of the Invention

[0006] [Issue resolved]

[0007] In the planetary gear device according to Patent Document 1, the structure is in a shape in which the outer peripheral surface of the ring gear and the inner peripheral surface of the housing are fitted together. Therefore, when the ring gear moves during operation of the planetary gear device, the outer peripheral surface of the ring gear and the inner peripheral surface of the housing will contact each other over a slightly wider range.

[0008] Thus, in a state in which there is contact between the ring gear and the housing, vibration of the planetary gear mechanism transmitted to the ring gear is easily transmitted to the housing, and therefore there is a problem that the planetary gear device will also tend to generate noise.

[0009] Specifically, preferably, the generation of vibration and noise is suppressed when there is an alignment inaccuracy (such as tilt) between the axis of the housing and the axis of the bracket supporting the planetary gears meshing with the ring gear due to manufacturing tolerances in the components (including various gears) and tolerances during assembly.

[0010] An object of the present disclosure is to solve problem areas such as those described above, and to provide a structural unit, a planetary gear device, and an actuator that can suppress the transmission of vibrations from a gear mechanism and suppress noise generated by the planetary gear device.

[0011] [Solution to the problem]

[0012] One form of a structural unit according to the present disclosure includes a ring gear (e.g., an internal gear or similar element including gear teeth extending inwardly) having an outer peripheral surface extending in an axial direction such that a first protruding portion is formed on the outer peripheral surface, and a housing having an inner peripheral surface disposed facing the outer peripheral surface of the ring gear with a gap therebetween such that a second protruding portion is formed on the inner peripheral surface. Movement of the ring gear in a circumferential direction can be limited by linear or point contact between the first protruding portion and the second protruding portion. The outer peripheral surface and / or the inner peripheral surface can have a convex shape curved in an outer radial direction.

[0013] One form of a planetary gear device according to the present disclosure includes a structural unit as described above, one or more planetary gears meshing with the ring gear, a sun gear meshing with the one or more planetary gears positioned at a center of the one or more planetary gears, and a carrier rotatably supporting the one or more planetary gears.

[0014] One form of an actuator according to the present disclosure includes a planetary gear device as described above, and a motor connected to the planetary gear device for driving the planetary gear device.

[0015] [Effect]

[0016] The present disclosure enables suppression of transmission of vibration from a gear mechanism, and suppression of noise generated by a planetary gear device. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a longitudinal sectional view of an actuator along an axial direction according to an embodiment of the present disclosure, the actuator including a planetary gear device having a structural unit.

[0018] Figure 2 is a front view of a structural unit viewed from one side along an axial direction.

[0019] Figure 3 is a front view of a housing main body of the structural unit viewed from one side along an axial direction.

[0020] Figure 4 is a longitudinal sectional view of a housing main body of the structural unit along an axial direction.

[0021] Figure 5 is a perspective view showing a first housing element of a housing main body.

[0022] Figure 6 This is a front view of the ring gear of the structural unit viewed from one side in the axial direction.

[0023] Figure 7 It is a plan view of the ring gear of the structural unit.

[0024] Figure 8 is a perspective view of the ring gear of the structural unit.

[0025] Figure 9 It is a longitudinal sectional view provided for explaining the operation of the structural units included in the planetary gear device.

[0026] Figure 10 is a front view of a first modified example of the structural unit according to the embodiment of the present disclosure, viewed from one side in the axial direction.

[0027] Figure 11 It is a front view of the housing main body in the structural unit of the first modified example.

[0028] Figure 12 It is a cross-sectional view taken along the axial direction, depicting the housing main unit.

[0029] Figure 13 is a front view of the ring gear in the structural unit of the first modified example viewed from one side in the axial direction.

[0030] Figure 14 is a side view depicting the ring gear.

[0031] Figure 15 is a front view of a second modified example of the structural unit according to the embodiment of the present disclosure.

[0032] Figure 16 is a partial cross-sectional view of the structural unit taken in the axial direction, depicting a second modified example of the structural unit according to the embodiment of the present disclosure.

[0033] Figure 17 2 is a front view of a housing main body of a second modified example.

[0034] Figure 18 is a cross-sectional view taken along the axial direction, illustrating a housing main body of a second modified example.

[0035] Figure 19A is a front view of the ring gear of the structural unit of the second modified example viewed from one side, and Figure 19B is a side view of the ring gear.

[0036] Figure 20 is a front view of the structural unit, viewing a third modified example of the structural unit according to the embodiment of the present invention from one side in the axial direction.

[0037] Figure 21A is a front view of the housing main body of the structural unit of the third modified example viewed from one side in the axial direction, and Figure 21B It is a longitudinal cross-sectional view of the housing main unit taken along the axial direction.

[0038] Figure 22A is a front view of a ring gear according to a third modified example of the structural unit of one embodiment of the present invention, viewed from one side in the axial direction, and Figure 22B yes Figure 22A Side view of the ring gear.

[0039] Figure 23 is a longitudinal sectional view of a structural unit according to a fourth modified example, taken in the axial direction. DETAILED DESCRIPTION

[0040] The embodiments according to the present disclosure are explained in more detail below based on the accompanying drawings.

[0041] Figure 1 : is a longitudinal sectional view taken along the axial direction of an actuator according to one embodiment of the present disclosure, the actuator including a planetary gear device having a structural unit. It should be noted that the planetary gear device and the actuator according to the following embodiment are examples of the planetary gear device and the actuator according to the present disclosure; the present disclosure is not limited to the following embodiment. In the following description, Figure 1 The lateral direction in the diagram shall be referred to as the "X direction" or the "axial direction", wherein the leftward direction shall be referred to as the "+X direction", and the rightward direction shall be referred to as the "-X direction". Figure 1 , the direction perpendicular to the X-axis shall be referred to as the "Y direction" or "radial direction", wherein the radial direction toward the outside shall be referred to as the "+Y direction", and the radial direction toward the inside shall be referred to as the "-Y direction". Figure 1 In the present invention, the direction around the X-axis shall be referred to as the "circumferential direction". Specifically, in Figure 1 In the case body 5, the side of the case body 4 that is open to enable attachment of the connection cover unit 41 shall be referred to as "one side" (-X direction side), and the opposite side (which is the side having the opening 57a of the opening / closing portion 57 of the case body 4) shall be referred to as "the other side" (+X direction side). However, the present invention is not limited to this, and instead, the side of the case body 4 having the opening 57a of the opening / closing portion 57 can be read as "one side", and the side of the case body 4 that is open to enable attachment of the connection cover unit 41 can be read as "the other side".

[0042] refer to Figure 1An actuator 1 according to the first embodiment, a planetary gear device 3 included in the actuator 1 , and a structural unit 10 provided with the planetary gear device 3 are explained.

[0043] <Actuator Structure>

[0044] Figure 1 The depicted actuator is used as, for example, an actuator 1 of a power tailgate of an automobile. Note that there is no particular limitation on the application of the actuator 1 .

[0045] The actuator 1 has a motor (electric motor) 2 and a planetary gear device 3 connected to the motor 2 .

[0046] <Motor>

[0047] The motor 2 has a motor main body 21 and a rotating shaft 22. The motor 2 operates under the control of a control portion (not shown) to rotate the rotating shaft 22, thereby driving the planetary gear device 3.

[0048] <Overall Structure of Planetary Gear Device 3>

[0049] The planetary gear device 3 reduces the speed of the rotation input from the motor 2 at a predetermined reduction ratio, and outputs the rotation from the output shaft 87 .

[0050] The planetary gear device 3 includes, for example, a housing 5 having a connection cover unit 41 and a housing main unit 4, and a planetary gear mechanism 6 contained within the connection cover unit 41 and the housing main unit 4. The planetary gear mechanism 6 includes, for example, a plurality of planetary gear mechanisms (a first planetary gear mechanism 7 and a second planetary gear mechanism 8) arranged in the axial direction, and an output shaft 87.

[0051] <Shell 5>

[0052] In the housing 5, in this embodiment, a plurality of planetary gear mechanisms 7 and 8 are connected as a planetary gear mechanism 6, which is contained by the connection cover unit 41 and the housing main body 4 to achieve multi-stage reduction. In the housing 5, the planetary gear mechanism 6 reduces the rotation of the rotating shaft 22 driven by the motor 2 in two stages to output the rotation from the output shaft 87.

[0053] <Connecting cover unit 41>

[0054] The connecting cover unit 41 is a member used, for example, to attach the motor 2 to the planetary gear mechanism 3. Furthermore, the connecting cover unit 41 is combined with the housing main body 4 to form a housing space for accommodating the planetary gear mechanism 6 therein. An opening 31a, through which the rotating shaft 22 of the motor 2 passes, is formed in the center of the connecting cover unit 41. The rotating shaft 22 passing through the opening 31a is fixed to the sun gear 71 of the planetary gear mechanism 6, as described below. The connecting cover unit 41 is made of a synthetic resin, for example, formed by injection molding.

[0055] <Housing host 4>

[0056] For example, Figure 1 As shown, the housing main body 4 is opened on one side (−X direction side) in the axial direction to enable attachment of the connection cover unit 41 , wherein the planetary gear mechanism 6 is placed inside through the open portion.

[0057] The main housing 4 includes a first housing element 40, in which the first planetary gear mechanism 7 is housed, and a second housing element 50, in which the second planetary gear mechanism 8 is housed, with the output shaft 87 of the second planetary gear mechanism 8 protruding from the second housing element. Note that the main housing 4, and specifically the first housing element 40 and the second housing element 50, are made of a synthetic resin, for example, formed by injection molding.

[0058] The first housing element 40 houses an annular first ring gear 90 that is configured to surround a sun gear 71 and a plurality of planetary gears 72, as described below. The second housing element 50 has an annular second ring gear portion 56 that is configured to surround a sun gear 81 and a plurality of planetary gears 82, as described below.

[0059] The first housing element 40 is an example of a “housing” of the structural unit 10 in the present disclosure. The first housing element 40 configures the structural unit 10 together with the first ring gear 90 serving as part of the first planetary gear mechanism 7 accommodated by the first housing element 40 .

[0060] <First Housing Element 40>

[0061] refer to Figures 2 to 5 The first housing element 40 as the housing in the structural unit 10 according to the embodiment of the present disclosure is explained. Figure 2 is a front view of the structural unit viewed from one side (-X direction side) in the axial direction, and Figure 3 This is a front view of the housing main body of the structural unit viewed from one side along the axial direction. Figure 4 It is a longitudinal cross-sectional view of the housing main unit taken along the axial direction. Figure 5 is a perspective view depicting a first housing element.

[0062] The first housing element 40 is a cylindrical main body that is open on one side (-X direction side), and is provided in combination with the second housing element 50 at an open end surface portion 40a on the other side (+X direction side). In the present embodiment, the first housing element 40 and the second housing element 50 are formed as a single unit, wherein their hollow interiors communicate with each other to form a space for accommodating the planetary gear mechanism 6.

[0063] like Figures 1 to 5 As shown, the first housing element 40 in this embodiment has a first cylinder 44 having an inner peripheral surface 46 facing the outer peripheral surface 92 of the first ring gear 90 with a gap therebetween. A second protrusion 45 serving as a stopper is formed on the inner peripheral surface 46.

[0064] The first housing element 40 limits the movement of the first ring gear 90 in the circumferential direction by contact between the second protrusion portion 45 and the first protrusion portion 95 of the first ring gear 90, and accommodates the first ring gear 90 in a floating state (a state in which movement is possible in all directions).

[0065] The first housing element 40 supports the first ring gear 90 so as to be movable by contact between the second protruding portion 45 and the first protruding portion 95, by point contact or linear contact thereof, so that the axis of the first ring gear 90 can be tilted relative to the axis of the first housing element 40. For example, the first housing element 40 includes the first ring gear 90 so as to enable easy movement within the first cylinder 44, such as pitch and roll.

[0066] The first cylinder 44 is provided integrally with the second cylinder 54. The outer peripheral surface of the first cylinder 44 configures the outer peripheral surface of the second housing member 50, and also configures the outer peripheral surface of the housing main body 4.

[0067] The first cylinder 44 is provided to surround the first ring gear 90 in addition to the sun gear 71, planetary gears 72 and carrier 73 configuring the first planetary gear mechanism 7. The first cylinder 44 has an inner peripheral surface 46 surrounding the sun gear 71, planetary gears 72, carrier 73 and first ring gear 90.

[0068] An engaging portion 42 for securely engaging with the connecting cover unit 41 is provided on the opening edge portion on one side of the first cylinder 44. In this embodiment, the engaging portion 42 is a tab portion protruding from the opening edge portion, the tab portion being spaced apart at predetermined intervals in the circumferential direction. The tab portion engages with the engaging portion (provided in the connecting cover unit 41) to restrict relative movement between the connecting cover unit 41 and the housing main body 4 in the axial and circumferential directions.

[0069] The inner peripheral surface 46 of the first cylinder 44 is arranged to correspond to the outer peripheral surface 92 of the first ring gear 90 so that the first ring gear 90 can rotate (described below). The inner peripheral surface 46 has a shape that enables relative movement with the outer peripheral surface 92 of the first ring gear 90. In the present embodiment, the inner peripheral surface 46 is a convex-shaped surface (which may be abbreviated as a "convex surface" hereinafter) that is curved so as to be recessed in the outer radial direction. The inner peripheral surface 46 is formed to be recessed in the radial direction into the axial center portion and is set at a prescribed gap from the outer peripheral surface 92 of the ring gear 90. It should be noted that the shape of the inner peripheral surface 46 may alternatively be defined by the relationship with the outer peripheral surface 92 of the ring gear 90, as described in detail below. The inner peripheral surface 46 and / or the outer peripheral surface 92 are formed in a convex shape.

[0070] The second convex portion 45 contacts the first convex portion 95 of the first ring gear 90 contained in the first cylinder 44 to restrict movement of the first ring gear 90 at least in the circumferential direction.

[0071] In the present embodiment, the second convex portion 45 is formed on the inner peripheral surface 46 so as to extend in the axial direction (from one side toward the other side in the axial direction).

[0072] like Figure 4 and Figure 5 As shown, the second protrusion portion 45 is provided with an end portion positioned on the inner side in the radial direction, bent so as to produce a shape protruding to the side surface in which the first protrusion portion 95 is positioned, formed to achieve point contact or linear contact with the first protrusion portion 95.

[0073] In this embodiment, if Figures 2 to 4 As shown, the second convex portions 45 are provided in pairs on portions of the inner peripheral surface 46 of the first cylinder 44 along the circumferential direction. Figure 6 、 Figure 7 、 Figure 9 ) The first protruding portion 95 of the first ring gear 90 is inserted between these paired second protruding portions 45, wherein the movement of the first ring gear 90 within the first housing element 40 is restricted by contact with these second protruding portions 45.

[0074] In this embodiment, when taken along a cross section perpendicular to the axial direction, each of the second convex portions 45 has a peaked cross-sectional shape and has an end portion extending in the axial direction, the end portion protruding at a constant height from the inner peripheral surface 46. The end portions are formed in a convex shape that protrudes toward each other in the direction in which they face each other in the circumferential direction (in the axial center portion thereof). That is, the end portions of the second convex portions 45 forming a pair are bent so as to form a convex shape toward the side, wherein the first convex portion 95 is positioned in the circumferential direction so that the spacing between the end portions of the second convex portions 45 can be narrower in the axial center portion than at the axial end portions.

[0075] Note that the second protrusions 45 are not necessarily formed in pairs. Note that in this embodiment and in the first to fifth modified examples described below, the second protrusions 45 may have any shape as long as the shape makes point contact or linear contact with the first ring gear 90 in the circumferential direction when the first ring gear 90 moves within the first housing element 40.

[0076] <Second Housing Element 50>

[0077] The second housing element 50 includes a second cylinder 54 and a second ring gear portion 56 formed on the inner wall of the second cylinder 54. The second ring gear portion 56 is cut, for example, at an angle relative to the axial direction. That is, the second housing element 50 includes the second ring gear portion 56 configured as a helical gear, for example.

[0078] The opening / closing portion 57 of the housing main body 4 has an opening 57a formed, for example, into a cylinder, for passing the output shaft 87 of the planetary gear mechanism 6. In this way, the torque output from the output gear 87a provided on the end of the output shaft 87 can be transmitted to an external mechanism. The housing main body 4 is made of a synthetic resin formed, for example, by injection molding.

[0079] <Planetary Gear Mechanism 6>

[0080] like Figure 1 As shown, the planetary gear mechanism 6 is housed in the housing main body 4 to reduce the speed of rotation transmitted from the motor 2 and output the rotation from the output gear 87 a of the output shaft 87 .

[0081] The planetary gear mechanism 6 has a first planetary gear mechanism 7 and a second planetary gear mechanism 8 arranged in the axial direction.

[0082] <First Planetary Gear Mechanism 7>

[0083] The first planetary gear mechanism 7 includes a sun gear 71, a plurality of planetary gears 72 arranged around the periphery of the sun gear 71 (centered on the sun gear 71), a carrier 73 that rotatably supports the plurality of planetary gears 72, and a first ring gear 90. The first planetary gear mechanism 7 may be provided with at least one planetary gear 72, and in the present embodiment, three planetary gears 72 are provided.

[0084] The sun gear 71 is an "external gear" in which a sun tooth portion 71a is formed on its outer peripheral surface, and is fixed to the rotating shaft 22 of the motor 2 so as to be able to rotate concentrically with the rotating shaft 22. The sun gear 71 rotates, which is driven by the motor 2. In the present embodiment, the sun tooth portion 71a has helical teeth cut at an angle with respect to the axis of the sun gear 71, so the sun gear 71 of the present embodiment can be a "helical gear".

[0085] The planetary gears 72 are external gears having planetary tooth portions 72 a formed on their outer peripheral surfaces. The plurality of planetary gears 72 are arranged equidistantly between the sun gear 71 and the first ring gear 90, and each meshes with both the sun gear 71 and the first ring gear 90. In this embodiment, each of the plurality of planetary gears 72 is arranged on a single circle centered on the axis of the first planetary gear mechanism 7 and is rotatably supported by the carrier 73. In this embodiment, the planetary tooth portions 72 a have helical teeth cut at an angle relative to the axis of the planetary gear 72, so the planetary gears 72 in this embodiment can be "helical gears."

[0086] Each of the planetary gears 72 rotates around its own axis (planetary axis 76) based on the rotation of the sun gear 71. In addition, each of the planetary gears 72 revolves around the sun gear 71 based on its own rotation and engagement with the first ring gear 90. The revolving axis of each planetary gear 72 may coincide with the axis of the sun gear 71.

[0087] The bracket 73 is capable of rotatably supporting the planetary gears 72. In addition, the bracket 73 rotates based on the revolution of the planetary gears 72, wherein its rotation is transmitted to the second planetary gear mechanism 8. In addition, in the present embodiment, the bracket 73 is formed as a cylinder, wherein the planetary gears 72 are contained in a housing opening (not shown) formed in its outer peripheral surface. Each of the planetary gears 72 is rotatably supported in the housing opening by a corresponding planetary axis 76 oriented in the axial direction. In the present embodiment, each planetary gear 72 is attached in a certain state, wherein a part of the planetary gear protrudes from the housing opening in the outer radial direction, protruding from the outer peripheral surface of the bracket 73. The planetary tooth portion 72a is thereby engaged with the internal tooth portion 91 of the first ring gear 90.

[0088] <First Ring Gear (Ring Gear) 90>

[0089] Figures 6 to 8 It is a figure provided for explaining the first ring gear 90 corresponding to the ring gear as the structural unit 10. Specifically, Figure 6 is a front view of the ring gear of the structural unit viewed from one side in the axial direction; Figure 7 is a plan view of the ring gear of the structural unit; and Figure 8 is a perspective view of the ring gear of the structural unit.

[0090] The first ring gear 90 has an inner peripheral surface and an outer peripheral surface 92 extending in the axial direction of the first ring gear 90. An inner tooth portion 91 is formed on the inner peripheral surface. In this embodiment, the inner tooth portion 91 forms a helical gear having helical teeth cut at an angle relative to the axis of the first ring gear 90. It should be noted that the rounded diameter of the tooth tips in the first ring gear 90 is larger than the diameter of the cylindrical bracket 73, which is contained within the interior of the first ring gear 90 and holds the planetary gears 72. The planetary tooth portion 72a protruding from the outer peripheral surface of the bracket 73 meshes with the inner tooth portion 91 of the first ring gear 90.

[0091] The outer peripheral surface 92 of the first ring gear 90 is provided in a shape corresponding to the inner peripheral surface 46 of the first cylinder 44 of the first housing element 40 .

[0092] In this embodiment, the outer peripheral surface 92 is formed into a convex surface (convex surface), wherein the central portion in the axial direction of the first ring gear 90 or the axial direction of the output of the actuator is formed in a convex shape to extend the furthest in the outer radial direction. In this embodiment, the outer peripheral surface 92 is formed to have a gap with a substantially constant spacing along the inner peripheral surface 46 of the first cylinder 44 to maintain a fixed floating state. That is, the first ring gear 90 is arranged to face the inner peripheral surface 46 of the first cylinder 44 (with a gap therebetween), which is a convex surface with a shape that is concave toward the outside, so that the outer peripheral surface 92 (which is a convex surface with a shape that is protruding toward the outside) can be loosely fitted within the first cylinder 44.

[0093] like Figure 2 and Figures 6 to 8 As shown, first convex portions 95 are formed on the outer peripheral surface 92 of the first ring gear 90. The first convex portions 95 engage with the paired second convex portions 45 formed on the inner peripheral surface 46 of the housing main body 4 in the circumferential direction with a gap therebetween.

[0094] In the present embodiment, the first convex portion 95 is provided so as to correspond to the pair of second convex portions 45 and to be inserted between the pair of second convex portions 45 .

[0095] In this embodiment, the first protruding portion 95 has a substantially triangular cross-sectional shape when cut by a plane perpendicular to the axial direction and extends in the axial direction. The first protruding portion 95 has a position bent into a convex shape to facilitate contact with the second protruding portion 45 when there is movement in the circumferential direction.

[0096] The first raised portion 95 has an inclined surface portion 95a and a rounded top portion 95b, the inclined surface portion standing at an angle to the outer peripheral surface 92 of the first ring gear 90, and the rounded top portion is positioned at a position where the inclined surface portion 95a rising from both sides intersects. The height of the first raised portion 95 corresponds to the convex shape of the outer peripheral surface 92, wherein the first raised portion 95 is provided in a rib at a constant height from the outer peripheral surface 92 (which is a convex surface). The first raised portion 95 is formed so that the axial direction center portion in the inclined surface portion 95a is wider in the circumferential direction, as shown in FIG. Figure 8 As depicted. When the first raised portion 95 is inserted between the pair of second raised portions 45, this facilitates point contact or linear contact. While these are formed across the entire width of the first ring gear 90, they may alternatively be formed across a portion thereof. The first ring gear 90 is made of, for example, a synthetic resin. Note that, as described below, the first ring gear 90 is formed of a synthetic resin having a lower hardness than the synthetic resin used to form the housing main body 4.

[0097] The housing main body 4 (first housing element 40) and the first ring gear 90 are physically separated, and a gap is formed between them when the actuator 1 is not in operation. The first ring gear 90 is allowed to move within the housing main body 4 in an amount corresponding to this gap. Allowing the first ring gear 90 to move within the housing main body 4 means allowing rotation about the axial direction (that is, in the circumferential direction) as well as rolling in a direction perpendicular to the axial direction. Therefore, further movement of the first ring gear 90 about the axis is prevented by the first protrusion 95 formed on the first ring gear 90, which contacts the paired second protrusions 45.

[0098] <Second Planetary Gear Mechanism 8>

[0099] The second planetary gear mechanism 8 reduces speed at a predetermined reduction ratio and outputs the rotation transmitted from the first planetary gear mechanism 7. The second planetary gear mechanism 8 is provided to the other side ( Figure 1The second planetary gear mechanism 8 is provided in the housing space of the housing main body 4, in the second housing element 50 of the housing main body 4, and specifically at a portion corresponding to the second ring gear portion 56. Note that the second planetary gear mechanism 8 can alternatively be omitted.

[0100] In the present embodiment, the second planetary gear mechanism includes a sun gear 81, planetary gears 82, a carrier 83 that rotatably supports the planetary gears 82, and an output shaft 87. The second planetary gear mechanism 8 can include a single planetary gear 82, but in the present embodiment includes three planetary gears 82.

[0101] The sun gear 81 is an "external gear" and has sun tooth portions 81a on its outer peripheral surface. In the present embodiment, the sun tooth portions 81a have helical teeth that are cut at an angle with respect to the axis of the sun gear 81, so the sun gear 81 can be a "helical gear".

[0102] In the present embodiment, the sun gear 81 is fixed in a state in which its axis coincides with the carrier 73 of the first planetary gear mechanism 7. Thereby, the sun gear 81 rotates interlocked with the rotation of the carrier 73 of the first planetary gear mechanism 7, in accordance with the rotation of the carrier 73 of the first planetary gear mechanism 7. That is, as the carrier 73 of the first planetary gear mechanism 7 rotates, the sun gear 81 rotates at the same rotational speed as the carrier 73 of the first planetary gear mechanism 7, because its rotational direction is the same as that of the carrier 73 of the first planetary gear mechanism 7.

[0103] The planetary gears 82 are external gears that have planetary tooth portions formed on their outer peripheral surfaces. The plurality of planetary gears 82 are disposed equidistantly spaced apart between the sun gear 81 and the second ring gear portion 56, and each mesh with both the sun gear 81 and the second ring gear portion 56. In the present embodiment, each of the plurality of planetary gears 82 is disposed on a single circle centered on the axis of the second planetary gear mechanism 8, and is rotatably supported on a planetary axis 86 of the carrier 83. In the present embodiment, the planetary tooth portions have helical teeth that are cut at an angle with respect to the axis of the planetary gear 82, so the planetary gears 82 in the present embodiment can be "helical gears".

[0104] Each of the planetary gears 82 rotates about its own axis (planetary axis 86) based on the rotation of the sun gear 81. Furthermore, each of the planetary gears 82 revolves about the sun gear 81 based on its own rotation and the meshing with the second ring gear portion 56. The revolution axis of each planetary gear 82 can coincide with the axis of the sun gear 81.

[0105] The carrier 83 rotatably supports the planetary gear 82 . The carrier 83 rotates based on the revolution of the planetary gear 82 , and the rotation thereof is transmitted to the output shaft 87 .

[0106] In the present embodiment, the bracket 83 has a gear holding portion 84 and an output holding portion 85 for holding an output shaft 87 .

[0107] The gear holding portion 84 holds the planetary gears 82 and is formed into a cylindrical shape. A housing opening (not shown) is formed on the outer peripheral surface of the gear holding portion 84, and the planetary gears 82 are accommodated within the housing opening. Each of the planetary gears 82 is rotatably supported within the housing opening by a corresponding planetary axis 86 oriented in the axial direction. In this embodiment, each planetary gear 82 is attached in a state in which a portion of the planetary gear protrudes from the housing opening in the outer radial direction, protruding from the outer peripheral surface of the bracket 83. The planetary tooth portion thereby meshes with the tooth portion of the second ring gear portion 56.

[0108] The output holding portion 85 is continuously provided with the gear holding portion 84 on the other side (output side) of the gear holding portion 84. The output holding portion 85 is formed as a cylinder having a smaller diameter than the gear holding portion 84, and the output shaft 87 is fixed to the inside of the output holding portion 85 in the radial direction.

[0109] The output shaft 87 is formed in the shape of a shaft and is held on the bracket 83 in this embodiment so as to rotate together with the bracket 83. The output shaft 87 has knurled teeth on the outer periphery of its end portion on its output side. These teeth form an output gear on the end portion of the output shaft 87.

[0110] <Operation of Actuator 1>

[0111] An example of the operation of the actuator 1 will be described below. First, when Figure 1 When the motor 2 is operated, the rotation shaft 22 rotates in the first direction or the second direction. The following description will focus on the case where the rotation shaft 22 rotates in the first direction.

[0112] Note that in the following description, the first direction relative to the rotation direction of various components refers to the direction when the first direction is viewed from the other side ( Figure 1 On the other hand, in the following description, the second direction relative to the rotation direction of various components refers to the direction when viewed from the other side ( Figure 1 The left side in the figure) is the direction opposite to the clockwise direction when observing various components.

[0113] When the rotating shaft 22 rotates in the first direction, the sun gear 71 rotates in the first direction according to the rotation of the rotating shaft 22. In accordance with the rotation of the sun gear 71, each of the three planetary gears 72 meshing with the sun gear 71 rotates (rotates) in the second direction about its own axis (planetary axis 86). Based on the rotation of the planetary gears 72 and the meshing of the planetary gears 72 with the first ring gear 90, the planetary gears 72 rotate (revolve) in the first direction about the rotation axis of the sun gear 71. In accordance with the rotation (revolution) of the planetary gears 72, the bracket 73 rotates in the first direction about its own axis (an axis that coincides with the axis of the sun gear 71).

[0114] When the bracket 73 rotates in the first direction and rotates in this manner, the sun gear 81 fixed to the bracket 73 rotates 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 (rotate on their own). In addition, the planetary gears 82 rotate in the second direction (rotate on their own) because they are meshed with the second annular gear portion 56, and through this rotation, the planetary gears 82 rotate in the first direction (revolve) around the axis of the second planetary gear mechanism 8. As the planetary gears 82 rotate (revolve) in the first direction, the bracket 83 rotates in the first direction with its own axis as the center. The rotation of the bracket 83 is transmitted to the output shaft 87 retained on the bracket 83.

[0115] Although the case where the rotating shaft 22 rotates in the first direction is explained as an example of the operation of the actuator 1 , the operation of the actuator 1 can be similarly explained by reversing the rotation direction of each gear for the case where the rotating shaft 22 rotates in the second direction.

[0116] As described above, with the planetary gear mechanism, the housing main unit 4 and the first ring gear 90 are physically separated in the structural unit 10. Therefore, when the actuator 1 is not operating, a gap is formed between the housing main unit 4 (first housing element) and the first ring gear 90. When the actuator 1 is operating, the first ring gear 90 can rotate about the axis and can move along the convex surface within the housing main unit 4 in a direction perpendicular to the axis by an amount equivalent to the provided gap.

[0117] When in a position where the second protruding portions 45 are separated from the first protruding portions 95 in the circumferential direction, the first ring gear 90 rotates in the first direction (clockwise), and the first protruding portions 95 formed on the first ring gear 90 come into point contact or linear contact with the corresponding second protruding portions 45 formed on the housing main body 4. Although this prevents the first ring gear 90 from rotating further clockwise, the first ring gear 90 is held by the first housing element 40 of the housing main body 4 so that its axis can tilt relative to the axis of the housing main body 4. It should be noted that in this embodiment, the second protruding portions 45 are formed in pairs, so that even if the first ring gear 90 is to rotate in the second direction (counterclockwise), linear contact can similarly exist, and the first ring gear 90 can be held with the ability to tilt while restricting the rotation of the first ring gear 90 about its axis.

[0118] Figure 9 It is a longitudinal sectional view for explaining the operation of the structural unit 10 built into the planetary gear device 3. In this embodiment, the outer peripheral surface 92 of the first ring gear 90 and the inner peripheral surface 46 of the first cylinder 44 are both convex surfaces, thereby enabling relative movement in all directions while resisting separation.

[0119] like Figure 9 As shown, when the motor 2 is driven to actuate the planetary gear mechanism 6 in this embodiment, the meshing of the planetary gears 82 and the like causes the first ring gear 90 to move within the first cylinder 44 of the first housing element 40. As a result, the first protruding portion 95 contacts the second protruding portion 45 in the circumferential direction. The first ring gear 90 is movable in all directions, with movement in the circumferential direction being restricted by point contact or linear contact between the first protruding portion 95 and the second protruding portion 45.

[0120] This makes it possible to achieve ideal meshing with the tilt-accommodating planetary gears even when the axis of the carrier 73 supporting the planetary gears 72 meshing with the first ring gear 90 is not accurate in its alignment, such as when it is angled relative to the axis of the housing main body 4 (first housing element 40). Therefore, this embodiment makes it possible to achieve improved robustness against inaccurate alignment between the gears, thereby making it possible to suppress the transmission of vibrations from the ring gear side and suppress the noise generated by the planetary gear device.

[0121] It should be noted that the synthetic resin used to form the first housing element 40 and the housing main body 4 can be, for example, polyarylate (PAAR), polyacetal (POM), polyamide (PA), polycarbonate (PC), polybutylene terephthalate (PBT), polyethersulfone (PES), polyetheretherketone (PEEK), etc. The synthetic resin used to form the first ring gear 90 and the first housing element 40 (including the first cylinder 44) can be the same material or can be different materials. They can be appropriately selected within the scope of producing the effects of the present disclosure. In addition, with respect to the synthetic resin material (material) used to form the first cylinder 44 and the first ring gear 90, the main components can use the same synthetic resin material, and the density of the synthetic resin, etc. can be changed so that for a suitable embodiment, the synthetic resin used to form the first cylinder 44 can be harder.

[0122] (Modified embodiment)

[0123] The present disclosure is not limited to the above-described embodiment, but various modifications and applications are possible. In the above-described embodiment, in the structure of the structural unit 10 having the first housing element 40 and the first ring gear 90, both the inner peripheral surface 46 of the first cylinder 44 of the first housing element 40 and the outer peripheral surface 92 of the first ring gear 90 contained in the first cylinder 44 are surfaces having a convex shape.

[0124] Here, the first housing element 40 and the first ring gear 90 can use any structure as long as the first ring gear 90 is supported so as to be able to move, so that the axis of the first ring gear 90 can be tilted relative to the axis of the first housing element 40 through point contact or linear contact between the first protrusion portion 95 and the second protrusion portion 45.

[0125] In the following Figures 10 to 23 In the description of the various modified examples, structures different from those of the housing main unit 4 and the first ring gear 90 are described, and the same names and the same reference symbols may be assigned to the same structural elements, and their description may be omitted.

[0126] In the structural unit 10A, as a first modified example, as Figures 10 to 14 As depicted, the second convex portion 45 of the first housing element (housing) 40 and the first convex portion 95 of the first ring gear 90 of the structure of the structural unit 10 are reversed. That is, the shape is such that the second convex portion 45A is inserted between the paired first convex portions 95A.

[0127] The first ring gear 90A has an outer peripheral surface 92A extending in the axial direction. The outer peripheral surface 92A is a convex surface protruding in the outer radial direction, similar to the first ring gear 90, and a first convex portion 95A configured similarly to the second convex portion 45 extends in the axial direction on the outer peripheral surface 92A.

[0128] The distal end portions of the first convex portions 95A are provided in a pair on the outer peripheral surface 92A, and the axial direction center portions are formed in a convex shape that convex in directions facing each other in the circumferential direction.

[0129] On the other hand, the first housing element 40A is arranged to surround the first ring gear 90A and has an inner peripheral surface 46A that is arranged to face the outer peripheral surface 92A of the first ring gear 90A (with a gap). Inner peripheral surface 46A has a convex surface with a concave shape that is recessed in the outer radial direction, similar to inner peripheral surface 46, and is provided in the first cylinder 44A. Inner peripheral surface 46A has a second convex portion 45A that extends in the axial direction, similar to inner peripheral surface 46. Second convex portion 45A is arranged similarly to first convex portion 95. Second convex portion 45A in the first modified example has a triangular cross-sectional shape, formed so as to have the same shape that continues in the axial direction.

[0130] In the first housing element 40A, when the first ring gear 90A rotates in the circumferential direction with the operation of the planetary gear device 3, the second convex portion 45A enters between the paired first convex portions 95A, thereby achieving the same effect as in the above-described structural unit 10.

[0131] In addition, Figure 15 to Figure 1 In the first housing element 40B of the structural unit 10B of the second modified example illustrated in FIG9 , the paired second protrusions 45 are configured such that the paired second protrusions 45B extend parallel to each other in the axial direction. The inner peripheral surface 46B of the first cylinder 44B of the first housing element 40B has a concave convex shape, with the axial center portion being the most concave. The second protrusions 45B are arranged in pairs, extending from the convex inner peripheral surface 46B with the same cross-sectional shape and the same height.

[0132] On the other hand, when comparing the first ring gear 90B with the first ring gear 90, the outer peripheral surface does not have a convex surface, but the outer peripheral surface 92B is a cylinder parallel to the axis. The protrusion 95B is provided so as to protrude in the outer radial direction as a first convex portion in the axial direction center portion of the outer peripheral surface 92B.

[0133] The protruding portion 95B is conical and has a sharp top portion. The protruding portion 95B is capable of contacting the inner peripheral surface 46B, which is the convex surface of the first housing element 40B.

[0134] Even when the structural unit 10B is in Figure 15 In the depicted state, when the first ring gear 90B is moved by the operation of the planetary gear device 3, the first ring gear 90B moves in the circumferential direction, and the protruding portion 95B enters between the paired second protruding portions 45B, and so on, to make point contact or line contact with the second protruding portions 45B. In the structural unit 10B of the second modified example, neither the outer peripheral surface of the first ring gear 90 nor the inner peripheral surface of the first housing element 40 is a convex surface. In this structure, the first housing element 40B supports the first ring gear 90B so that it can move, so that the axis of the first ring gear 90B can be tilted relative to the axis of the first housing element 40B.

[0135] Will Figure 20 to Figure 2 A structural unit 10C of the third modified example of the structural unit depicted here is different from the structural unit 10 in the shape of the second convex portion 45 of the first housing element (housing) 40 and the shape of the first convex portion 95 of the first ring gear 90.

[0136] The first ring gear 90C has an outer peripheral surface 92C extending in the axial direction. The outer peripheral surface 92C is a convex surface that protrudes in the radial direction, similar to the first ring gear 90. The outer peripheral surface 92C protrudes in the outer radial direction and forms a pair of first protrusions 95C extending in the axial direction.

[0137] As depicted in Figure 22, the first protrusions 95C have a triangular cross-sectional shape having the same size regardless of the position in the axial direction and are formed at the same height from the outer peripheral surface 92C. The pair of first protrusions 95C are provided parallel to each other on the outer peripheral surface 92C.

[0138] On the other hand, the first housing element 40C is provided so as to surround the first ring gear 90C, wherein the first housing element 40C has an inner peripheral surface 46C of the first cylinder 44C, which is provided to face the outer peripheral surface 92C of the first ring gear 90C (with a gap therebetween). Like the inner peripheral surface 46, the inner peripheral surface 46C is a convex surface having a concave shape that is concave in the outer radial direction and corresponds to the outer peripheral surface 92C.

[0139] The inner peripheral surface 46C has a second convex portion 45C extending in the axial direction, as in the structure of the inner peripheral surface 46. The second convex portion 45C is provided on the convex surface so as to extend in the axial direction.

[0140] The second convex portion 45C is inserted between the pair of first convex portions 95C in the first ring gear 90C to make point contact or linear contact in the circumferential direction.

[0141] As shown in FIG21, the second protrusion 45C has a triangular cross-section perpendicular to the axial direction, that is, a rib having a triangular cross-section, and is formed to be wider in the central portion in the axial direction. Therefore, when the first protrusion 95C is contacted in the circumferential direction, the second protrusion 45C first contacts the central portion thereof, which protrudes in the circumferential direction.

[0142] Furthermore, when the second protrusion 45C enters between the paired first protrusions 95C, point contact or linear contact with the first protrusion 95C is made at the center thereof. This further improves robustness against inaccurate alignment by enabling the first ring gear 90C and the planetary gears 72 to properly mesh even when the axis of the first ring gear 90C is tilted relative to the axis of the first housing element 40.

[0143] Note that with the structural units 10, 10A, and 10C of the above-described embodiments and the first and third modified examples, the outer peripheral surfaces 92, 92A, and 92C of the first ring gears 90, 90A, and 90C and the inner peripheral surfaces 46, 46A, and 46C of the first housing elements 40, 40A, and 40C are all convex surfaces. This makes it possible to restrict the movement of the first ring gear in the radial direction toward the housing space of the first housing element by adjusting the slack (that is, the size of the gap) between the first ring gear and the first housing element.

[0144] For example, in Figure 23 In the structural unit 10D of the fourth modified example depicted, the inner peripheral surface 46D of the first housing element 40D and the outer peripheral surface 92D of the first ring gear 90D (depicted by hatching for convenience) are convex surfaces, and the first ring gear 90D is contained within the first housing element 40D. Thus, by having both surfaces being convex, the first ring gear 90D can be restricted in its axial movement relative to the first housing element 40D, including to the other side (+X side). It should be noted that the first cylinder 44D, the second convex portion 45D, and the first convex portion 95D have the same structure and function as, for example, the first cylinder 44, the second convex portion 45, and the first convex portion 95.

[0145] Therefore, in the first ring gear, for example, there is no need to provide a protruding portion (indicated by P) on the end face of the opening on the other side to contact the end face of the housing inside the housing. Note that the structural units 10A to 10D of the first to fourth modified examples described above can each replace the structural unit 10 to produce the planetary gear device 3 and the actuator 1 incorporating the planetary gear device 3.

[0146] As depicted in structural units 10 and 10A to 10D, the outer peripheral surface of the first ring gear (ring gear) and / or the inner peripheral surface of the first housing element (housing) have a convex surface. Furthermore, the first raised portion of the outer peripheral surface and / or the second raised portion of the inner peripheral surface may have any shape, as long as the portion that contacts another portion in the circumferential direction is configured as a curved portion having a shape that protrudes so as to make point contact or line contact in the circumferential direction. This contact allows the first ring gear to be enclosed by the first housing element in a state where its movement in the circumferential direction within the first housing element is restricted, and even when the axis of the first ring gear is tilted relative to the axis of the first housing element, the first ring gear does not lose its function as the first ring gear in the gear mechanism.

[0147] Furthermore, although the description is directed to a case where the housing main unit 4 is used as a part of a planetary gear device, the present application is not limited thereto, but may alternatively be used as a part of another gear mechanism.

[0148] The embodiments according to the present disclosure have been explained above. It should be noted that the above description shows suitable embodiments of the present disclosure, but the scope of the present disclosure is by no means limited thereto. In other words, the above description of the structure of the device and the shapes of the various components are examples, and it is obvious that various modifications and additions can be made to these examples within the scope of the present disclosure.

[0149] [Possibility of use in industry]

[0150] The planetary gear device and the actuator according to the present disclosure may be built into various mechanical equipment.

[0151] [Explanation of Reference Symbols]

[0152] 1: Actuator

[0153] 2: Motor

[0154] 3: Planetary gear unit

[0155] 4: Shell host

[0156] 5: Shell

[0157] 6: Planetary gear mechanism

[0158] 7: First planetary gear mechanism

[0159] 8: Second planetary gear mechanism

[0160] 10, 10A, 10B, 10C, 10D: Structural units

[0161] 21: Motor host

[0162] 22: Rotation axis

[0163] 31a: Opening

[0164] 40, 40A, 40B, 40C, 40D: first housing element (housing)

[0165] 40a: Open end surface

[0166] 41: Connecting cover unit

[0167] 42: Joint

[0168] 57a: Opening

[0169] 44, 44A, 44B, 44C, 44D: First cylinder

[0170] 45, 45A, 45B, 45C: Second raised portion

[0171] 46, 46A, 46B, 46C: Inner peripheral surface

[0172] 50: Second shell element

[0173] 54: Second Cylinder

[0174] 56: Second ring gear part

[0175] 57: Open / Close Section

[0176] 71, 81: Sun gear

[0177] 71a: Sun gear part

[0178] 72, 82: Planetary gears

[0179] 72a: Planetary gear part

[0180] 73, 83: Bracket

[0181] 76, 86: Planetary axis

[0182] 81a: Sun gear part

[0183] 84: Gear holding part

[0184] 85: Output hold part

[0185] 87: Output shaft

[0186] 87a: Gear

[0187] 90, 90A, 90B, 90C, 90D: First ring gear (ring gear)

[0188] 91: Inner tooth part

[0189] 92, 92A, 92B, 92C, 92D: Outer peripheral surface

[0190] 95, 95A, 95C, 95D: First raised part

[0191] 95A: Inclined surface section

[0192] 95b: Top

[0193] 95B: protrusion

Claims

1. A structural unit comprising: a ring gear having an outer peripheral surface extending in an axial direction, wherein a first protrusion portion is formed on the outer peripheral surface; and a housing having an inner peripheral surface that is arranged to face the outer peripheral surface of the ring gear with a gap therewith, wherein a second protruding portion is formed on the inner peripheral surface, and wherein movement of the ring gear in the circumferential direction is restricted by linear contact or point contact between the first protruding portion and the second protruding portion, wherein the outer peripheral surface and / or the inner peripheral surface is a convex-shaped surface curved in an outer radial direction, and The first protruding portion and / or the second protruding portion extend in the axial direction, and the axial center portion of the first protruding portion and / or the second protruding portion is bent into a shape extending in the circumferential direction so as to make point contact or linear contact with the protruding portion of the other.

2. The structural unit according to claim 1, wherein: The housing movably supports the ring gear so that the axis of the ring gear is tilted relative to the axis of the housing by linear contact or point contact between the first protruding portion and the second protruding portion.

3. The structural unit according to claim 1 or claim 2, wherein: The outer peripheral surface and the inner peripheral surface are surfaces each having a convex shape curved in the outer radial direction.

4. The structural unit according to claim 1 or 2, wherein: The surface of the convex shape is the inner peripheral surface, the inner peripheral surface being recessed in the outer radial direction; and The first convex portion of the outer peripheral surface is formed to move along the inner peripheral surface and contact the second convex portion in the circumferential direction.

5. A planetary gear device comprising: The structural unit according to any one of claims 1 to 4; one or more planetary gears meshing with the ring gear; a sun gear positioned at the center of the one or more planet gears and meshing with the one or more planet gears; and A carrier rotatably supports the one or more planetary gears.

6. The planetary gear device according to claim 5, further comprising: a second sun gear that rotates according to the rotation of the bracket; one or more second planetary gears, the one or more second planetary gears being disposed around the second sun gear and meshing with the second sun gear; a second bracket rotatably supporting the one or more second planetary gears; and a second housing, wherein internal teeth meshing with the one or more second planetary gears are formed on an inner peripheral surface of the second housing, wherein: The housing and the second housing are formed as a single unit.

7. An actuator comprising: The planetary gear device according to claim 5 or 6; and A motor is connected to the planetary gear device for driving the planetary gear device.

Images