JP7402682B2 - Separation structure between internal gear and housing, planetary gear device, actuator - Google Patents

Description

The present invention relates to a separation structure between an internal gear and a housing, a planetary gear device including the separation structure, and an actuator including the planetary gear device.

Planetary gear systems are used in various technologies such as automobiles and robots. Since a planetary gear device is constructed by combining a plurality of gears, noise and vibration are generated during operation. Techniques have been proposed to suppress the generation of noise and vibration during the operation of such planetary gear devices.

As a proposal for such a technique, Patent Document 1 discloses a planetary gear device in which an internal gear and a housing are separated, and a gap is provided between the two. The structure in which the internal gear and the housing are separated makes it difficult for vibrations to be transmitted from the internal gear to the housing, making it difficult to generate noise due to vibration.

Special Publication No. 6-74835

In the planetary gear device of Patent Document 1, the outer circumferential surface of the internal gear and the inner circumferential surface of the housing are formed to fit into each other. Therefore, when the internal gear moves during operation of the planetary gear device, the outer circumferential surface of the internal gear and the inner circumferential surface of the housing come into contact over a certain extent. As a result, when the internal gear and the housing are in contact with each other, vibrations of the planetary gear mechanism that have been transmitted to the internal gear are likely to be transmitted to the housing, and the resulting noise of the planetary gear mechanism is likely to occur.

The present invention was made in order to solve the above-mentioned problems, and it is possible to separate the internal gear and the housing, which can suppress the transmission of vibration from the planetary gear mechanism and the noise generated from the planetary gear mechanism. The present invention aims to provide a structure, a planetary gear device including the separation structure, and an actuator including the planetary gear device.

A separation structure for separating an internal gear and a housing according to the present invention includes an internal gear in which a first convex portion extending from one side in the axial direction to the other side is formed on the outer circumferential surface thereof, and one side in the axial direction a housing for accommodating the internal gear with a gap provided between the housing and the internal gear; Movement of the internal gear inside the housing is restricted by line contact between the first convex portion and the second convex portion.

Among the first convex portion and the second convex portion, one convex portion is formed in a pair with an interval, and the other convex portion is inserted between the one convex portion formed in the pair. At least one of the contact location on the one convex portion and the contact location on the other convex portion that make line contact may be formed as a curved surface.

The one protrusion is the second protrusion, the other protrusion is the first protrusion, and the first protrusion has a triangular shape when cut along a plane perpendicular to the axial direction. The second convex portion may be brought into contact with a slope having a cross section and formed in a planar shape.

Of the contact point of the first convex portion and the contact point of the second convex portion that make line contact, one may be a convex curved surface and the other may be a flat surface.

The contact location of the first convex portion and the contact location of the second convex portion that are in line contact may be convex curved surfaces.

Of the contact point of the first convex portion and the contact point of the second convex portion that make line contact, one may be a convex curved surface and the other may be a concave curved surface.

The internal gear and the housing may be made of synthetic resin, and the internal gear may be made of a synthetic resin having a lower hardness than the synthetic resin forming the housing.

The separation structure between an internal gear and a housing according to the present invention has an inner circumferential surface on which an internal gear is formed, and an outer circumferential surface on which a convex portion is formed on at least a part of the direction from one side to the other side in the axial direction. and an open end face extending between the inner circumferential surface and the outer circumferential surface at the other end, the internal gear is housed in the internal gear, and the internal gear is in contact with the convex part of the internal gear. and a cylindrical housing that limits circumferential movement of the internal gear inside the housing, the housing facing the open end surface on the other side of the internal gear. The opening end face on the other side has a contact portion protruding toward the contact surface portion, and the contact portion contacts the contact surface portion in the axial direction. This restricts movement of the internal gear toward the contact surface portion.

The planetary gear device according to the present invention includes the above-described separation structure between the internal gear and the housing, one or more planetary gears that mesh with the internal gear, and a planetary gear located at the center of the one or more planetary gears. Alternatively, it includes a sun gear that meshes with a plurality of planetary gears, and a carrier that rotatably supports the one or more planetary gears.

a second sun gear that rotates in the same manner as the carrier rotates as the carrier rotates; and one or more second sun gears that are arranged around the second sun gear and mesh with the second sun gear. a second carrier rotatably supporting the one or more second planetary gears, and a second carrier having internal teeth formed on the inner peripheral surface to mesh with the one or more second planetary gears. 2 housing, and the housing and the second housing may be integrally molded.

The planetary gear device according to the present invention includes a sun gear, one or more planet gears arranged around the sun gear and meshing with the sun gear, and a carrier rotatably supporting the one or more planet gears. In a planetary gear device comprising at least two stages of a planetary gear mechanism, of the at least two stages of planetary gear mechanism, the planetary gear mechanism that operates at the highest speed has a separation structure between the internal gear and the housing. The one or more planetary gears of the planetary gear mechanism are in mesh with the internal gear, and of the at least two stages of the planetary gear mechanism, the planetary gear mechanism that operates at the lowest speed is the planetary gear mechanism. The housing includes internal teeth formed on the inner peripheral surface to mesh with the one or more planetary gears.

An actuator according to the present invention includes the above planetary gear device and a motor connected to the planetary gear device and driving the planetary gear device.

According to the present invention, the contact range between the internal gear and the housing is narrower than in the prior art, making it difficult for vibrations caused by the planetary gear mechanism to be transmitted to the housing. This makes it possible to suppress the transmission of vibrations from the planetary gear mechanism and the noise generated from the planetary gear apparatus due to the vibrations of the planetary gear mechanism.

A perspective view of an actuator according to an embodiment of the present invention Front view of the actuator seen from arrow AII in Figure 1 A cross-sectional view of the actuator taken along cutting line III-III in Figure 2 An exploded perspective view of an actuator according to an embodiment of the present invention A sectional view of the second housing according to the embodiment of the present invention A perspective view of a second housing according to an embodiment of the present invention A perspective view of a first planetary gear mechanism according to an embodiment of the present invention A perspective view of a second planetary gear mechanism according to an embodiment of the present invention Diagram for explaining the relationship between the second housing and the internal gear according to the embodiment of the present invention An explanatory diagram focusing on the stopper formed in the second housing shown in FIG. 9 An explanatory diagram focusing on the movement limiting convex portion formed on the internal gear shown in FIG. 9 A diagram for explaining the state in which the internal gear shown in FIG. 9 rotates around the central axis and contacts the second housing. A diagram for explaining a state in which the internal gear shown in FIG. 9 moves in a direction perpendicular to the axis and contacts the second housing. A diagram for explaining the contact mode between the second housing and the internal gear as seen from the arrow XIV in FIG. 12. A schematic diagram comparing the movement-limiting convex portion shown in FIG. 11 with other examples of the movement-limiting convex portion. An explanatory diagram focusing on a contact point between an internal gear and a second housing according to another embodiment of the present invention 17A is a rear view of the internal gear as Modification 1, and FIG. 17B is a right side view of the same gear. FIG. A schematic diagram comparing a convex portion with a pointed tip and a convex portion with a round tip shown in Figure 17. 19A is a rear view of the internal gear as Modification 2, and FIG. 19B is a right side view of the same gear. FIG. 20A is a rear view of the internal gear as Modification 3, and FIG. 20B is a right side view of the same gear. FIG. 21A is a rear view of the internal gear as Modification 4, and FIG. 21B is a right side view of the same gear. FIG. 22A is a rear view of the internal gear as Modification 5, and FIG. 22B is a right side view of the same gear. FIG. 23A is a rear view of the internal gear as Modification 6, and FIG. 23B is a right side view of the same gear. FIG. 24A is a rear view of the internal gear as Modification 7, and FIG. 24B is a right side view of the same gear. FIG. 25A is a rear view of the internal gear as Modification 8, and FIG. 25B is a right side view of the same gear. FIG. 26A is a rear view of the internal gear as Modification 9, and FIG. 26B is a right side view of the same gear. FIG. 27A is a rear view of the internal gear as Modification 10, and FIG. 27B is a right side view of the same gear. FIG. 28A is a rear view of the internal gear as Modification 11, and FIG. 28B is a right side view of the same gear. FIG. 29A is a rear view of the internal gear as Modification 12, and FIG. 29B is a right side view of the same gear. FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a separation structure for separating an internal gear and a housing, a planetary gear device, and an actuator according to preferred embodiments of the present invention will be described with reference to the drawings. Note that in order to facilitate understanding of the drawings, in each figure, orthogonal coordinates having an X axis parallel to the axial direction of the actuator 1 according to the embodiment of the present invention, and Y and Z axes orthogonal to the X axis are shown. The system is illustrated.

(Configuration of actuator 1)
As shown in FIGS. 1 and 2, the actuator 1 includes, for example, a motor 10 and a planetary gear device 20 connected to the motor 10.

The motor 10 includes, for example, a motor body 11 and a rotating shaft 12, as shown in FIGS. 3 and 4. The motor 10 rotates the rotating shaft 12 and drives the planetary gear device 20 under the control of a control section (not shown).

The planetary gear device 20 reduces the rotation input by the motor 10 shown in FIG. 1 at a predetermined reduction ratio and outputs it from the output gear 86a. For example, as shown in FIGS. 3 and 4, the planetary gear device 20 includes a housing 50 having a first housing 30 and a second housing 40, and a planetary gear mechanism 60 housed inside the housing 50. .

The first housing 30 is, for example, a member for attaching the motor 10 to the planetary gear device 20. Further, the first housing 30 is combined with the second housing 40 to form an accommodation space S shown in FIG. 5 for accommodating the planetary gear mechanism 60 therein. As shown in FIG. 4, an opening 30a is formed in the center of the first housing 30, through which the rotating shaft 12 of the motor 10 passes. The rotating shaft 12 passed through the opening 30a is fixed (connected) to a sun gear 71 of the planetary gear mechanism 60, which will be described later. The first housing 30 is made of, for example, synthetic resin and is molded by injection molding.

For example, as shown in FIGS. 5 and 6, the second housing 40 has an open side (one side) to which the first housing 30 is attached, and the planetary gear mechanism 60 shown in FIG. can be accommodated. For example, as shown in FIG. 4, the planetary gear mechanism 60 includes a first planetary gear mechanism 70, a second planetary gear mechanism 80, and an output gear 86a, which are arranged along the axial direction. The planetary gear mechanism 60 decelerates the rotation brought about by the motor 10 (input) in two stages and outputs it from the output gear 86a. For example, as shown in FIG. 5, the second housing 40 includes a first part 41 in which the first planetary gear mechanism 70 is housed, a second part 42 in which the second planetary gear mechanism 80 is housed, and a second planetary gear mechanism It has a third portion 43 for projecting the output gear 86a of the gear mechanism 80 to the outside.

For example, as shown in FIGS. 5 and 6, the first portion 41 of the second housing 40 includes a cylindrical body 44 and a stopper extending along the axial direction (from one side to the other side in the axial direction). (second convex portion) 45. The stopper 45 has a mountain-shaped cross section when cut along a cross section perpendicular to the axial direction, and its shape and size are constant in the axial direction. Although the stopper 45 is formed in a partial range in the axial direction of the first portion 41, it may be formed over the entire range. For example, as shown in FIG. 9, the stoppers 45 are arranged in pairs on the inner wall 44a of the cylindrical body 44 in the circumferential direction. The pair of stoppers 45 are provided, for example, at six locations on the inner wall 44a of the cylindrical body 44 at equal intervals. For example, as shown in FIG. 10, the cross-sectional shape of each stopper 45 includes a rising portion 45a that forms an arc and gradually rises from the inner wall 44a of the cylindrical body 44, a rounded top portion 45c, and a rising portion 45a and a top portion 45c. It has a connecting portion 45b that connects the two while expanding. Note that the cross-sectional shape and size of the stopper 45 are constant in the axial direction. Therefore, as can be understood from, for example, FIG. 6, the rising portion 45a, the connecting portion 45b, and the top portion 45c are curved surfaces that are not curved in the direction parallel to the axis. A movement-limiting convex portion 75 of the internal gear 74 shown in FIG. 9, which will be described later, is inserted between the pair of stoppers 45, thereby restricting movement of the internal gear 74 within the second housing 40.

The second portion 42 of the second housing 40 includes, for example, a cylindrical body 46 and an internal toothed portion 47 formed on the inner wall of the cylindrical body 46, as shown in FIGS. 5 and 6. The internal teeth 47 are, for example, carved obliquely at an angle with respect to the axial direction. That is, the second portion 42 having the internal tooth portion 47 constitutes, for example, a helical gear.

The third portion 43 of the second housing 40 has, for example, a cylindrical shape and has an opening 43a through which the output gear 86a of the planetary gear mechanism 60 shown in FIG. 4 passes. Thereby, the torque output from the output gear 86a can be transmitted to an external mechanism. The second housing 40 is made of synthetic resin, for example, and is molded by injection molding.

In this specification, for convenience, the side of the second housing 40 that is open so that the first housing 30 can be attached is referred to as one side (-X direction side) in FIGS. A certain side of the third portion 43 of the second housing 40 having the opening 43a is called the other side (+X direction side). However, the present invention is not limited to this, and the side having the opening 43a of the third portion 43 of the second housing 40 is considered as one side, and the side of the second housing 40 that is open so that the first housing 30 is attached. It may be reread and interpreted so that it is on the other side.

For example, as shown in FIG. 4, the planetary gear mechanism 60 is housed in the housing 50, reduces the rotation speed transmitted from the motor 10, and outputs it from the output gear 86a. The planetary gear mechanism 60 includes, for example, a first planetary gear mechanism 70 and a second planetary gear mechanism 80 that are arranged along the axial direction.

For example, as shown in FIG. 7, the first planetary gear mechanism 70 includes a sun gear 71, three (plural) planetary gears 72 arranged around the sun gear 71, and three (plural) ) and an internal gear 74. Although only two planetary gears 72 are shown in FIG. 7 due to the perspective view, another planetary gear 72 is provided at a position hidden behind the carrier 73.

The sun gear 71 is an external gear in which a sun tooth portion 71a is formed on the outer peripheral surface, and the rotating shaft 12 of the motor 10 shown in FIG. 4 is fixed (connected) to the sun gear 71. As a result, the sun gear 71 rotates as the motor 10 operates. The sun tooth portion 71a has, for example, spiral teeth cut diagonally with respect to the axis of the sun gear 71. That is, the sun gear 71 is, for example, a helical gear.

The planetary gear 72 is, for example, an external gear in which a planetary tooth portion 72a is formed on the outer peripheral surface. The planetary tooth portion 72a has, for example, spiral teeth cut diagonally with respect to the axis of the planetary gear 72. That is, the planetary gear 72 is, for example, a helical gear. The 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 located between the three planet gears 72, and the sun tooth portion 71a is meshed with each of the planet tooth portions 72a of the three planet gears 72.

The carrier 73 is formed, for example, in a cylindrical shape, and three housing openings 73a for housing the planetary gears 72 are formed on its outer peripheral surface. Each of the planetary gears 72 is rotatably supported within the receiving opening 73a by an axially oriented pin 76, as shown in FIG. The planetary gear 72 is attached, for example, with a part of the planetary tooth portion 72a protruding from the outer peripheral surface of the carrier 73. This allows the planetary tooth portion 72a to mesh with an internal tooth portion 74a of an internal gear 74, which will be described later.

For example, as shown in FIGS. 3 and 7, the internal gear 74 has an internal toothed portion 74a formed on its inner peripheral surface. The internal gear portion 74a is, for example, a helical gear having spiral teeth cut diagonally with respect to the axis of the internal gear 74. The diameter of the tip circle of the internal gear 74 is larger than the diameter of the cylindrical carrier 73. Therefore, a carrier 73 holding the planetary gear 72 is housed inside the internal gear 74 . The planetary tooth portion 72a protruding from the outer peripheral surface of the carrier 73 meshes with the internal tooth portion 74a of the internal gear 74.

Further, on the outer circumferential surface of the internal gear 74, for example, as shown in FIG. is formed. The movement-limiting convex portions 75 are provided, for example, in correspondence with the pair of stoppers 45, and are formed at six locations similarly to the pair of stoppers 45. The movement limiting convex portion 75 has a generally triangular cross section when cut along a plane perpendicular to the axial direction. Further, as shown in FIG. 11, the movement limiting convex portion 75 is located, for example, at a location where a linear oblique side portion 75a rising from the outer circumferential surface 74b of the internal gear 74 and an oblique side portion 75a rising from both sides intersect. It has a rounded top 75b. Note that, as shown in FIG. 7, the shape and size of the cross section of the movement limiting convex portion 75 are constant in the axial direction (extending uniformly from one side to the other side in the axial direction). The oblique side portion 75a of the movement-limiting convex portion 75 constitutes a plane area. Although the movement-limiting convex portion 75 is formed over the entire width of the internal gear 74, it may be formed only over a part of the width. The internal gear 74 is made of synthetic resin, for example. Note that, as will be described later, the internal gear 74 is made of a synthetic resin having a lower hardness than the synthetic resin forming the second housing 40 shown in FIG.

The internal gear 74 has a contact convex portion (contact portion) 742 that projects in the axial direction on an end surface 740 on the other side in the axial direction. The other end surface 740 is an open end surface extending between the inner circumferential surface and the outer circumferential surface at the other end in the axial direction. The contact convex portion 742 is in contact with the second housing 40 in the axial direction. In the second housing 40 , the contact portion with which the contact convex portion 742 comes into contact is such that the internal gear 74 is in contact with the other end in the axial direction within the second housing 40 . This is a contact surface portion 411 that restricts sideward movement. The contact surface portion 411 is provided facing the other end surface 740 of the internal gear. Note that the contact surface portion 411 is provided on the other side of the first portion 41, but in this embodiment, it also serves as one end surface of the second portion 42.
The internal gear 74 is housed in the second housing 40 in contact with the contact surface portion 411 of the second housing 40 via the contact convex portion 742 in the axial direction.

The contact convex portion 742 is provided to protrude toward the contact surface portion 411 side. In this embodiment, a plurality of contact protrusions 742 are provided in the circumferential direction on the end surface 740. The number of contact protrusions 742 is determined by a configuration in which the internal gear 74 stably contacts the contact surface portion 411 within the second housing 40, for example, a structure in which the internal gear 74 contacts the contact surface portion 411 without tilting the shaft around the axial direction. Any number of them may be provided. The end surface 740 is provided with at least three contact convex portions 742 that make point contact with the contact surface portion 411 .
Further, a plurality of contact convex portions 742 may be provided protruding from the end surface (opening end surface) 740 at equal intervals in the circumferential direction, or may be provided in a plurality protruding from the end surface 740 at unequal intervals in the circumferential direction. . Further, the number of contact convex portions 742 is not particularly limited, and it is sufficient that at least one contact convex portion 742 is provided. Furthermore, the contact convex portion 742 may be configured such that the cross-sectional area perpendicular to the axial direction becomes smaller as it moves away from the end surface 740 that is the other open end surface. Further, the contact convex portion 742 may be provided in the same manner as the end surface 740 on the open end surface of the internal gear 74 on one side to which the first housing 30 is attached. Thereby, transmission of vibration to the first housing 30 or transmission of vibration from the first housing 30 can be suppressed.

The contact convex portion 742 contacts the second housing 40 on the other side of the internal gear 74 in the axial direction, and serves as a vibration path for vibrations generated on the internal gear 74 side to the second housing 40 . The contact convex portion 742 has a cross-sectional area perpendicular to the axial direction of the portion of the internal gear 74 that contacts the second housing 40 in the axial direction, which is larger than the cross-sectional area when the end surface 740 contacts the second housing 40 in the axial direction. is also smaller.

The contact convex portion 742 may be configured such that the cross-sectional area perpendicular to the axial direction gradually decreases toward the other side in the axial direction, that is, toward the contact surface portion 411. The contact convex portion 742 suppresses transmission of vibrations generated within the internal gear 74, that is, vibrations caused by driving the first planetary gear mechanism 70, to the second housing 40.

In this embodiment, the contact convex portion 742 is formed in a hemispherical shape, as shown in FIGS. 3 and 7, and makes point contact with the contact surface portion 411 of the second housing 40 on the other side in the axial direction. . Thereby, transmission of vibration in the axial direction from the internal gear 74 side to the second housing 40 is more effectively suppressed.

Although the contact convex portion 742 in this embodiment has a hemispherical configuration, it may be configured in any shape as long as it reduces the propagation area of vibration toward the other end in the axial direction. Good too. For example, the contact convex portion 742 may be formed in the shape of a cone with the tip on the contact surface portion 411 side being the apex. The internal gears provided with the contact convex portions as described above will be described later as Modifications 1 to 11 of the internal gears used in the separation structure, planetary gear device, and actuator of this embodiment.

As shown in FIG. 9, the second housing 40 and the internal gear 74 are physically separated, and a gap is formed between them when the actuator 1 is not operating. Therefore, the internal gear 74 is in a floating state within the second housing 40 and rotates around the axial direction within the second housing 40 by the gap provided between the internal gear 74 and the second housing 40. Movement in a direction perpendicular to the axial direction is allowed. Then, the movement limiting convex portion 75 formed on the internal gear 74 comes into contact with the pair of stoppers 45, thereby restricting further movement of the internal gear 74.

The second planetary gear mechanism 80, which is another planetary gear mechanism, includes, for example, a sun gear 81, three planetary gears 82, and a carrier 83 that rotatably supports the three planetary gears 82, as shown in FIG. and an output shaft 86. Although only two planetary gears 82 are shown in FIG. 8 due to the perspective view, another planetary gear 82 is provided at a position hidden behind the carrier 83.

The sun gear 81 is, for example, an external gear having a sun tooth portion 81a formed on its outer peripheral surface, and is fixed to the carrier 73 of the first planetary gear mechanism 70 shown in FIG. 7 with their axes aligned with each other. (connected). As a result, as the carrier 73 of the first planetary gear mechanism 70 rotates, the sun gear 81 rotates in the same manner as the rotation of the carrier 73 of the first planetary gear mechanism 70 (synchronized, interlocked). That is, as the carrier 73 of the first planetary gear mechanism 70 rotates, the sun gear 81 rotates in the same rotational direction as the carrier 73 of the first planetary gear mechanism 70 and at the same rotational speed as the carrier 73 of the first planetary gear mechanism 70 . Rotate. The sun tooth portion 81a has, for example, spiral teeth cut diagonally with respect to the axis of the sun gear 81. That is, the sun gear 81 is, for example, a helical gear.

The planetary gear 82 is, for example, an external gear in which a planetary tooth portion 82a is formed on the outer peripheral surface. The planetary tooth portion 82a has, for example, spiral teeth cut diagonally with respect to the axis of the planetary gear 82. That is, the planetary gear 82 is, for example, a helical gear. For example, the three planetary gears 82 are arranged at equal intervals on the same circle centered on the axis of the second planetary gear mechanism 80. The sun gear 81 is located between the three planet gears 82, and the sun tooth portion 81a meshes with each of the planet tooth portions 82a of the three planet gears 82. Further, the planetary gear 82 is meshed with an internal tooth portion 47 formed in the second housing 40 shown in FIGS. 5 and 6.

The carrier 83 includes, for example, a gear holding section 84 that holds the planetary gear 82 and an output shaft holding section 85 that holds the output shaft 86. The gear holding portion 84 is formed, for example, in a cylindrical shape, and three accommodation openings 84a for accommodating the planetary gears 82 are formed on its outer peripheral surface. Each of the planetary gears 82 is rotatably mounted within a receiving opening 84a by an axially oriented pin 87, as shown in FIG. The planetary gear 82 is attached to the carrier 83 with a portion of the planetary tooth portion 82a protruding from the outer circumferential surface of the carrier 83. This allows the planetary tooth portion 82a to mesh with the internal tooth portion 47 formed on the second housing 40. Further, as shown in FIG. 8, the output shaft holding portion 85 is formed in a cylindrical shape with a smaller diameter than the gear holding portion 84, and the output shaft holding portion 85 has a central portion for holding the output shaft 86. A fitting hole 85a is formed.

For example, the output shaft 86 is held by the carrier 83 and rotates together with the carrier 83. The output shaft 86 has an output gear 86a having knurled teeth on the shaft. That is, the output shaft 86 constitutes a gear having knurled teeth, for example.

(Operation of actuator 1)
Next, an example of the operation of the actuator 1 will be described. First, when the motor 10 shown in FIG. 4 operates, the rotating shaft 12 rotates in the first direction or the second direction. Hereinafter, a case where the rotating shaft 12 rotates in the first direction will be described.

Note that the first direction regarding the rotational direction of each member is a clockwise direction when each member is viewed from the direction indicated by arrow AII shown in FIG. On the other hand, the second direction regarding the rotational direction of each member is a counterclockwise direction when each member is viewed from the direction indicated by arrow AII shown in FIG.

When the rotating shaft 12 rotates in the first direction, the sun gear 71 shown in FIGS. 3 and 7 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 meshed with the sun gear 71 each rotate (rotate) in the second direction. Further, since the planetary gear 72 is meshed with the internal gear 74, by rotating (rotating) in the second direction, the planetary gear 72 rotates (revolutions) around the axis of the first planetary gear mechanism 70 in the first direction. As the planetary gear 72 rotates (revolutions), the carrier 73 rotates (rotates) in the first direction about its own central axis.

In this way, when the carrier 73 rotates in the first direction, the sun gear 81 shown in FIGS. 3 and 8 fixed to the carrier 73 rotates in the first direction. As the sun gear 81 rotates in the first direction, the three planetary gears 82 meshed with the sun gear 81 each rotate (rotate) in the second direction. In addition, since the planetary gear 82 meshes with the internal tooth portion 47 shown in FIGS. Rotate (revolution) in the direction. As the planetary gear 82 rotates (revolutions) in the first direction, the carrier 83 rotates (rotates) in the first direction about its own central axis. The rotation of the carrier 83 is then transmitted to the output shaft 86 held by the carrier 83.

In the above, a case has been described in which the rotating shaft 12 rotates in the first direction, but if the rotating shaft 12 is rotated in the second direction, the rotation direction of each gear is simply reversed, and the actuator 1 is rotated in the same way. Be able to explain the operation.

As described above, the second housing 40 and the internal gear 74 are physically separated. When the actuator 1 is not operating, a gap is formed between the second housing 40 and the internal gear 74. When the actuator 1 operates, the internal gear 74 is allowed to rotate around the axis and move in a direction perpendicular to the axis within the second housing 40 by the amount of the gap provided. For example, if the internal gear 74 rotates in the first direction (clockwise) from the state shown in FIG. , makes line contact with a corresponding stopper 45 formed on the second housing 40. As a result, the internal gear 74 can no longer rotate clockwise. Since the stoppers 45 are formed in pairs, even when the internal gear 74 rotates in the second direction (counterclockwise), they are in line contact and the rotation of the internal gear 74 around the axis is restricted. .

Further, suppose that the internal gear 74 moves from the state shown in FIG. 9 in a direction perpendicular to the axis, for example, upward in the figure. Then, as shown in FIG. 13, the movement limiting convex portion 75 formed on the internal gear 74 at the upper part in the figure comes into line contact with the pair of stoppers 45 formed on the second housing 40. As a result, the internal gear 74 cannot move upward any further, and its movement in the direction perpendicular to the axis is restricted. At this time, the top 75b of the internal gear 74 (more specifically, the top 75b of the movement limiting convex portion 75) comes into contact with the second housing 40 (more specifically, the inner wall 44a of the cylindrical body 44). contact). Note that the restriction on the movement of the internal gear 74 in the direction orthogonal to the axis is not limited to the case where the internal gear 74 moves upward. Since the six movement-limiting protrusions 75 and the pair of stoppers 45 are arranged at equal intervals in the circumferential direction, movement of the internal gear 74 in various directions such as the vertical direction, the left-right direction, and the diagonal direction is restricted. be able to.

(effect)
According to the above embodiment, in the structure of the separated internal gear 74 and the second housing 40, even if the internal gear 74 moves during operation of the actuator 1, the stopper 45 and the movement limiting convex portion 75 are The movement of the internal gear 74 can be restricted by line contact. FIG. 12 shows a state in which the internal gear 74 and the second housing 40 are in line contact as the internal gear 74 rotates around the axis. At this time, the pair of stoppers 45 and the movement limiting convex portion 75 come into contact at all six locations, but the manner of contact is the same. Therefore, one contact point in the upper part of the figure will be described with reference to the enlarged view of FIG. 12. As shown in the figure, the contact point between the connecting portion 45b of the stopper 45, which is illustrated by a bulging convex curve, and the oblique side portion 75a of the movement limiting convex portion 75, which is illustrated by a straight line, is indicated by a contact point P1. Can be done. In other words, contact occurs within an extremely limited range. Note that the cross section of the second housing 40 and the cross section of the internal gear 74 have a constant shape and size in the axial direction. Therefore, the contact between the connecting portion 45b and the oblique side portion 75a is a contact between a convex curved surface having no bend in a direction parallel to the axis and a plane parallel to the axis. As a result, the contact between the internal gear 74 and the second housing 40 is a line contact along the axial direction parallel to the X-axis, as in the contact area 90 shown in FIG. 14 .

Further, FIG. 13 shows a state in which the second housing 40 and the internal gear 74 are in contact with each other due to the internal gear 74 moving in a direction perpendicular to the axis, for example, upward in the figure. As shown in FIG. 13, there are four contact points between the second housing 40 and the internal gear 74, indicated by contact points P2 to P5. As shown in the enlarged view of FIG. 13, the contact points P2 and P3 are connected to the connecting portion 45b of the stopper 45, which is illustrated by a bulging convex curve, and the oblique side portion 75a of the movement-limiting convex portion 75, which is illustrated by a straight line. This is the point of contact. Similar to the above, such a contact point is a contact between a convex curved surface having no bend in a direction parallel to the axis and a plane parallel to the axis, so that the two come into line contact. Further, the contact between the stopper 45 and the movement limiting convex portion 75 at the contact points P4 and P5 is also a line contact since the convex curved surface and the flat surface are in contact.

In this way, by arranging the chevron-shaped stoppers 45 having a convex curved surface in pairs and inserting the triangular movement-limiting convex part 75 having a flat slope between them, the internal gear 74 Even when the internal gear 74 rotates around the axis or moves in a direction perpendicular to the axis, the contact between the internal gear 74 and the second housing 40 can be kept in line contact. Since the contact area between the internal gear 74 and the second housing 40 that are in line contact in this manner is small, vibrations from the operating internal gear 74 are difficult to be transmitted to the second housing 40 . This suppresses the vibration of the second housing 40 that is transmitted and generated from the first planetary gear mechanism 70, thereby suppressing the noise generated from the planetary gear apparatus 20 due to the vibration caused by the first planetary gear mechanism 70. be able to.

In addition, the "line contact" described in this specification refers to a contact state in which the contact portion has a linear shape, and is simply indicated by one or more points serving as contact points in each cross section. It does not only refer to a contact state where the contact area is closed (point contact), but also includes a contact state in which the width W in the contact area 90 is sufficiently smaller than the length L, as shown in FIG. shall be. In addition, "line contact" described in this specification further refers to contact in a scattered manner so that the width W in the contact area 90 forms a line shape when an imaginary line is drawn along the axial direction (sparse contact). (contact) shall also be included. Moreover, the term "line contact" described in this specification further includes a contact state in which the width W in the contact area 90 is not in the axial direction but in a linear shape so as to draw a diagonal line. Furthermore, the term "line contact" described herein means that the width W in the contact area 90 forms a line shape when an imaginary line is drawn not in the axial direction but in the diagonal direction. It also includes a contact state in which contact is made in a scattered manner (contact is sparse).

In the above-described embodiment, a mode in which the first convex portion and the second convex portion are in line contact is shown and described, but the present invention is not limited to this, and the contact method can be appropriately selected depending on the mode. For example, the first convex portion and the second convex portion may be in point contact or may be in surface contact.

Further, as shown in FIG. 11, the cross section of the movement limiting convex portion 75 cut along a plane perpendicular to the axis is triangular, and the tapered apex 75b is directed outward, so that the inner surface during injection molding is reduced. The gear 74 can be removed from the mold easily. Thereby, the yield can be improved.

Further, as shown in FIG. 15, linear oblique sides 75a are formed on both sides of a cross section of the movement limiting convex portion 75 taken along a plane perpendicular to the axial direction. Further, in FIG. 15, as a comparative example of the movement-limiting convex portion 75, a movement-limiting convex portion 100 having a bulged shape on both sides is illustrated by a two-dot chain line. Comparing the two, the cross-sectional area of the movement-limiting convex portion 75 is smaller than the cross-sectional area of the movement-limiting convex portion 100 by the area of the hatched area. As a result, in this embodiment, the weight of the internal gear 74 can be reduced, so that the load on the motor 10 can be reduced, and manufacturing costs can be reduced. Further, since the operating internal gear 74 can be made lighter, in this embodiment, the impact when the internal gear 74 contacts the second housing 40 can be reduced (suppressed), and therefore the vibration of the second housing can also be reduced. It can be made smaller (suppressed).

Further, the internal gear 74 is made of a synthetic resin having a lower hardness than the synthetic resin forming the second housing 40 . As the synthetic resin forming the internal gear 74 and the second housing 40, it is preferable to use engineering plastics or super engineering plastics from the viewpoints of mechanical strength, wear resistance, heat resistance, etc. Examples of these synthetic resins include ultra-high molecular weight polyethylene (UHPE), polyphenylene sulfide (PPS), polyarylate (PAR), polyacetal (POM), polyamide (PA), polycarbonate (PC), and polybutylene terephthalate (PBT). , polyether sulfone (PE
S), polyetheretherketone (PEEK), and the like.

The synthetic resins forming the internal gear 74 and the second housing 40 may be the same material or different materials. It can be selected as appropriate within the range that provides the effects of the present invention.

Among the above synthetic resins, examples of relatively soft synthetic resins suitable for forming the internal gear 74 include ultra high molecular weight polyethylene (UHPE), polyphenylene sulfide (PPS), polyarylate (PAR), and polyacetal (POM). ), it is desirable to use polyamide (PA). In addition, examples of relatively hard synthetic resins suitable for forming the second housing 40 include polycarbonate (PC), polybutylene terephthalate (PBT), polyether sulfone (PES), polyphenylene sulfide (PPS), and polyether. Preference is given to using etherketone (PEEK), polyacetal (POM), polyamide (PA). In addition, when using synthetic resin materials having the same main components as the synthetic resin material (material) forming the internal gear 74 and the second housing 40, the synthetic resin material forming the second housing 40 may be made by changing the density etc. of the synthetic resin. It is desirable that the resin be harder.

In this embodiment, by forming the internal gear 74 from a synthetic resin having a lower hardness than the second housing 40, it is possible to soften the impact when the internal gear 74 contacts the second housing 40. , the vibrations generated in the second housing 40 can be further reduced (suppressed). As a result, in this embodiment, it is possible to further reduce (suppress) the noise caused by the vibration of the second housing 40, and further to reduce the sound when the internal gear 74 and the second housing 40 collide. can be suppressed). Furthermore, noise generated from the planetary gear device 20 due to vibrations caused by the first planetary gear mechanism 70 can be suppressed.

Furthermore, in this embodiment, the configuration in which the housing and the internal gear are separated is not applied to the second stage planetary gear mechanism that rotates at low speed, but only to the first stage planetary gear mechanism that rotates at high speed. It is applied to In other words, in this embodiment, a structure in which the internal gear is floating is adopted for a mechanism that rotates at high speed where vibration and noise are likely to become large, and a structure in which the internal gear is floating is adopted for a mechanism that rotates at low speed where vibration and noise are relatively less likely to become large. , adopts a housing structure with internal teeth. As a result, in this embodiment, it is possible to suppress the vibration and noise of the planetary gear set caused by the planetary gear set, and also to prevent an unnecessary increase in the number of parts of the planetary gear set, and an increase in assembly work and assembly cost. Can be done. As a result, the manufacturing cost of the planetary gear device can be reduced. In this way, depending on the rotational mode of the planetary gear mechanism, two mechanisms with different configurations can be employed as appropriate, and both mechanisms can coexist.

(Modified example)
This invention is not limited to the embodiments described above, and various modifications and applications are possible. In the above embodiment, the second housing 40 is provided with a pair of stoppers 45, and the internal gear 74 is provided with a movement limiting convex portion 75 that is inserted between the pair of stoppers 45. However, the present invention is not limited to this, and the installation locations of the pair of stoppers 45 and the movement-limiting convex portion 75 are replaced, the movement-limiting convex portion 75 is provided on the inner peripheral surface of the second housing 40, and the outer circumference of the internal gear 74 is A configuration in which a pair of stoppers 45 are provided on the surface may be adopted.

Further, the cross section of the pair of stoppers 45 is made into a chevron shape, and the cross section of the movement limiting convex part 75 is made into a triangular shape. The cross-sectional shape may be changed such that the cross-sectional shape is chevron-shaped.

Further, the number of locations where the pair of stoppers 45 and the corresponding movement limiting protrusions 75 are installed is not particularly limited, and may be greater than the six locations shown in the above embodiment, or may be less. You can also use it as

Furthermore, by bringing the convex curved surface of the pair of stoppers 45 into contact with the flat surface of the movement-limiting convex portion 75, a line contact was made between the two, but a line contact can be achieved by bringing a piece of a different shape into contact. You can also do that. Next, another embodiment for realizing line contact will be described with reference to FIG. 16. The difference from the configuration shown in the enlarged view of FIG. 9 is that the cross section of the movement limiting convex portion (first convex portion) 175 is not triangular but has a rounded mountain shape. Note that the configuration of the second housing 40 is similar to the configuration shown in the enlarged view of FIG. 9 . In FIG. 16, the internal gear 174 is shown in solid lines when the actuator is not operating. Furthermore, the internal gear 174 indicated by the two-dot chain line moves upward and is in contact with the second housing 40 due to the actuator's operation. As shown in FIG. 16, the contact between the pair of stoppers 45 and the movement-limiting convex portion 175 is the contact between their convex curved surfaces, and the contact points P6 and P7 between the pair of stoppers 45 and the movement-limiting convex portion 175 Line contact occurs. In this way, in this embodiment, line contact is achieved by bringing convex curved surfaces with bulges into contact with each other.

In addition, the present invention is not limited to this, and the second housing 40 locally has a concave portion with a large curvature, the internal gear 74 has a convex curved surface with a smaller curvature, and the concave curved surface with a large curvature and the bulge. It is also possible to realize line contact by making contact with a convex curved surface having . In addition, the configuration itself for realizing line contact is arbitrary.

In addition, in other embodiments that realize the above-mentioned line contact, the configuration of the internal gear and the configuration of the second housing at the location where the line contact is made can be replaced.

Further, the actuator 1 is provided with a two-stage planetary gear mechanism including a first planetary gear mechanism 70 and a second planetary gear mechanism 80 as a speed reducer that reduces the rotation of the motor 10, but the number of stages can be set arbitrarily. be able to. For example, three or more stages of the planetary gear mechanism may be provided to further increase the reduction ratio, or the configuration may include only one stage of the planetary gear mechanism.

Further, in the above embodiment, the configuration in which the housing and the internal gear are separated is applied only to the first planetary gear mechanism 70, which is the first stage mechanism that rotates at high speed, and The second planetary gear mechanism 80, which is a mechanism, is equipped with a housing in which internal teeth are formed on the inner peripheral surface. However, the second planetary gear mechanism 80, which is the second stage mechanism, may also adopt a configuration in which the housing and the internal gear are separated to reduce vibration and noise.

Furthermore, in the above embodiment, a case has been described in which the present invention is used as a speed reducer that decelerates the rotation of the motor 10 and outputs it from the output gear 86a, but the application is not limited to this. For example, the part where the output shaft 86 shown in FIG. 8 is provided is the input side and the rotating shaft of the motor is connected, and the part where the sun gear 71 shown in FIG. 7 is provided is the output side and the output shaft is connected. Good too. Thereby, it can be used as a speed increaser that speeds up and outputs the rotation of the motor. Also in this case, since the first planetary gear mechanism 70 shown in FIG. 7 operates at higher speed, it is preferable to adopt a structure in which the internal gear and the housing are separated. Moreover, since the rotation of the motor is directly transmitted to the second planetary gear mechanism 80 shown in FIG. 8, it is preferable to adopt a structure in which the internal gear and the housing are separated, if necessary. Further, the present invention may be applied to industrial machines such as robots and machine tools, and play equipment such as so-called coffee cups.

Further, when using the present invention in various applications, when a planetary gear mechanism with three or more stages is provided, the separation structure of the internal gear and the housing is applied to the planetary gear mechanism that operates at the highest speed. Thereby, generation of vibration and noise can be effectively reduced. Furthermore, since the planetary gear mechanism that operates at the lowest speed generates less vibration and noise, a configuration is applied that includes a housing having internal teeth formed on the inner circumferential surface. This eliminates the need for an unnecessarily separate structure between the internal gear and the housing, which prevents an increase in the number of parts, assembly work, and assembly costs, and ultimately reduces production costs. .

Further, in the above embodiment, each gear used to transmit the power of the motor 10 to the output shaft 86 is described as a helical gear, but other gears may be used. For example, a spur gear may be used. As a result, rattling is more likely to occur at the meshing points than when helical gears are used, but even in such cases, by adopting the configuration of the present invention, vibration and noise of the planetary gear system can be reduced. can be reduced (suppressed).

(Modified example of internal gear)
<Modification example 1 of internal gear>
FIG. 17 is a diagram for explaining Modification 1 of the internal gear 74 according to the embodiment of the present invention, FIG. 17A is a rear view of the internal gear 74A as Modification 1, and FIG. 17B is a diagram of the same. It is a right view of gear 74A. As shown in FIGS. 17A and 17B, the internal gear 74A differs from the internal gear 74 only in the shape of the contact protrusion 742A.

The contact convex portion 742A protrudes toward the contact surface portion 411 side at an end surface (open end surface) 740A of the internal gear 74A on the side (the other side in the axial direction) that contacts the contact surface portion 411 of the second housing 40, and extends toward the contact surface portion 411 side. It is shaped like a square pyramid with the tip of the head as the apex.
As shown in FIG. 18A, the contact convex portion 742A is configured to have a sharp shape such that a tip (apex) 7424A that contacts the contact surface portion 411 is sharp. This makes it possible to reduce the contact area with the contact surface even when the contact protrusion is deformed, compared to the contact protrusion 742 with a round tip 7424 as shown in FIG. 18B. As a result, the contact convex portion 742A reduces vibrations more effectively than the contact convex portion 742 when vibrations generated on the internal gear 74A side, that is, on one side in the axial direction, are transmitted to the other side in the axial direction. It can be transmitted in a suppressed state.

<Modification example 2 of internal gear>
FIG. 19 is a diagram for explaining a second modification of the internal gear 74 according to the embodiment of the present invention, FIG. 19A is a rear view of the internal gear 74B as the second modification, and FIG. It is a right view of gear 74B. The internal gear 74B differs from the internal gear 74 only in the shape of the contact convex portion 742B, and the contact convex portion 742B is located on the side of the internal gear 74B that comes into contact with the contact surface portion 411 of the second housing 40 (in the axial direction). The end face (opening end face) 740B of the other side) protrudes toward the contact surface portion 411 and is formed in a triangular pyramid shape with the tip on the contact surface portion 411 side as the apex. Thereby, the same effects as Modification 1 can be obtained.

<Modification 3 of internal gear>
FIG. 20 is a diagram for explaining a third modification of the internal gear 74 according to the embodiment of the present invention, FIG. 20A is a rear view of an internal gear 74C as the third modification, and FIG. 20B is a diagram of the third modification. It is a right view of gear 74C. The internal gear 74C differs from the internal gear 74 only in the shape of the contact convex portion 742C. The contact convex portion 742C protrudes toward the contact surface portion 411 side at an end surface (open end surface) 740C of the internal gear 74C on the side that contacts the contact surface portion 411 of the second housing 40 (the other side in the axial direction). It is formed into a conical shape with the tip of the head as the apex. Thereby, the same effects as Modification 1 can be obtained.

<Modification example 4 of internal gear>
FIG. 21 is a diagram for explaining a modification 4 of the internal gear according to the embodiment of the present invention, FIG. 21A is a rear view of an internal gear 74D as modification 4, and FIG. 20B is a diagram showing the internal gear 74D as modification 4. 74D is a right side view. Internal gear 74D differs from internal gear 74 only in the shape of contact convex portion 742D.

The contact convex portion 742D protrudes toward the contact surface portion 411 from the end surface (open end surface) 740D of the internal gear 74D on the side that contacts the contact surface portion 411 of the second housing 40 (the other side in the axial direction), and has a rounded and spherical tip. It is formed as a rod-shaped body. Specifically, the contact convex portion 742D has a rod-shaped extending portion and a hemispherical portion provided at the tip of the extending portion. In this case, since the tip has a hemispherical shape, it makes point contact with the contact surface portion 411. Therefore, transmission of vibrations from the internal gear 74D side to the second housing 40 can be further suppressed.

<Modification example 5 of internal gear>
FIG. 22 is a diagram for explaining a fifth modification of the internal gear 74 according to the embodiment of the present invention, FIG. 22A is a rear view of the internal gear 74E as the fifth modification, and FIG. 22B is a rear view of the internal gear 74E as the fifth modification. It is a right view of gear 74E. The internal gear 74E differs from the internal gear 74 only in the shape of the contact protrusion 742E. The contact convex portion 742E protrudes toward the contact surface portion 411 at an end surface (open end surface) 740E of the internal gear 74E on the side (the other side in the axial direction) that contacts the contact surface portion 411 of the second housing 40, and when viewed from the back, It is shaped like a cross. The tip of the contact convex portion 742E has a sharp shape and makes point contact with the contact surface portion 411.

In this way, the contact protrusion 742E has a smaller cross-sectional area perpendicular to the axial direction, that is, a vibration propagation area along the axial direction, compared to the conical contact protrusions 742A to 742C and the rod-shaped contact protrusion 742D. It's getting smaller. Thereby, transmission of vibration from one side to the other side in the axial direction can be further suppressed.

<Modification example 6 of internal gear>
FIG. 23 is a diagram for explaining a sixth modification of the internal gear 74 according to the embodiment of the present invention, FIG. 23A is a rear view of the internal gear 74F as the sixth modification, and FIG. 22B is a diagram showing the internal gear 74F is a right side view. The internal gear 74F shown in FIG. 23 differs from the internal gear 74 only in the shape of the contact convex portion 742F.

The contact convex portion 742F is provided on the end face (open end face) 740F of the internal gear 74F on the side (the other side in the axial direction) that contacts the contact surface portion 411 of the second housing 40 so as to protrude toward the contact surface portion 411 side. A cross section perpendicular to the direction is formed in a cross shape. The outer shape of the contact convex portion 742F is curved so as to protrude toward the tip, and makes point contact with the contact surface portion 411 at the curved tip.

In this way, the contact protrusion 742F has a larger cross-sectional area perpendicular to the axial direction, that is, a vibration propagation area along the axial direction, compared to the conical contact protrusions 742A to 742C and the rod-shaped contact protrusion 742D. is getting smaller. Thereby, transmission of vibration from one side to the other side in the axial direction can be further suppressed.

<Modification example 7 of internal gear>
FIG. 24 is a diagram for explaining a seventh modification of the internal gear 74 according to the embodiment of the present invention, FIG. 24A is a rear view of an internal gear 74G as the seventh modification, and FIG. 24B is a diagram showing the same gear. 74G is a right side view. The internal gear 74G differs from the internal gear 74 only in the shape of the contact convex portion 742G. The contact convex portion 742G protrudes toward the contact surface portion 411 at an end surface (open end surface) 740G of the internal gear 74G on the side that contacts the contact surface portion 411 of the second housing 40 (the other side in the axial direction).

The contact convex portion 742G is an arcuate plate-shaped body that protrudes to the other side and is curved so that the center of the tip surface is the apex. In other words, the tip of the contact convex portion 742G is formed into a spherical shape. The contact protrusions 742G are provided parallel to each other at predetermined intervals in the circumferential direction on the end surface 740G.

The contact protrusion 742G has a smaller cross-sectional area perpendicular to the axial direction, that is, a vibration propagation area along the axial direction, compared to the conical contact protrusions 742A to 742C and the rod-shaped contact protrusion 742D. . Thereby, transmission of vibration from one side to the other side in the axial direction can be further suppressed.

<Modification example 8 of internal gear>
FIG. 25 is a diagram for explaining Modification 8 of the internal gear according to the embodiment of the present invention, FIG. 25A is a rear view of an internal gear 74H as Modification 8, and FIG. 24B is a diagram showing the internal gear 74H as Modification 8. 74H is a right side view. The internal gear 74H has a configuration in which the contact convex portion 742G is changed in the configuration of the internal gear 74G.

Specifically, the internal gear 74H has a contact convex portion 742H having the same shape as the contact convex portion 742G, and the side of the internal gear 74H that comes into contact with the contact surface portion 411 of the second housing 40 (the other side in the axial direction) The end face (opening end face) 740H protrudes toward the contact surface portion 411 side.

The contact convex portions 742H are arcuate plate-like bodies that protrude to the other side, and are provided at predetermined intervals in the circumferential direction on the end surface 740H, with respective surface portions (for example, the back surface) facing the central axis of the second housing 40. It is being Thereby, transmission of vibration from the internal gear 74H to the second housing 40 side can be further suppressed.

Further, the contact convex portion 742H is arranged such that each surface portion (in particular, the inner surface 7421 on the central axis side) of the contact convex portion 742H is arranged along the circumferential direction on the end surface 740H.
The internal gear 74H is provided so as to be floating in the circumferential direction within the second housing 40, and a lubricant such as grease is applied to the sliding portion of the internal gear 74H within the second housing 40. When lubricant is applied to the internal gear 74H, even if the internal gear 74H moves in the circumferential direction within the second housing 40, the lubricant tends to remain on the inner surface 7421 along the circumferential direction, and the second housing The internal gear 74H can be suitably held in a floating state within 40.

<Modification example 9 of internal gear>
FIG. 26 is a diagram for explaining Modification 9 of the internal gear according to the embodiment of the present invention, FIG. 26A is a rear view of an internal gear 74I as Modification 9, and FIG. 26B is a diagram showing the internal gear 74I as Modification 9. 74I is a right side view. The internal gear 74I has a configuration in which the contact convex portion 742G is changed in the configuration of the internal gear 74G.

Specifically, the internal gear 74I has a contact convex portion 742I having the same shape as the contact convex portion 742G, and the side of the internal gear 74I that contacts the contact surface portion 411 of the second housing 40 (the other side in the axial direction) The end face (opening end face) 740I protrudes toward the contact surface portion 411 side.

The contact convex portion 742I is an arcuate plate-like body that protrudes to the other side, and is spaced at a predetermined interval in the circumferential direction on the end surface 740I so that each surface portion (for example, the back surface) extends along the radial direction of the second housing 40. are arranged radially. Thereby, transmission of vibration from the internal gear 74I to the second housing 40 side can be further suppressed.

<Modification example 10 of internal gear>
The contact convex portions 742, 742A to 742I in the above-described embodiment and each modification example 1 to 8 are provided on each end surface (opening end surface) 740, 740A to 740I at equal intervals in the circumferential direction, six each. However, any number of them may be provided. For example, as shown in the internal gear 74J shown in FIG. 27, the contact convex portion 740J is formed in the circumferential direction at the end surface (opening end surface) 740J on the side (the other side in the axial direction) that contacts the contact surface portion 411 of the second housing 40. It may be provided so that three protruding portions are spaced apart from each other. The contact protrusion 740J is configured to have the same shape as the contact protrusion 740 as shown in FIG. 27, but is not limited to this, and may be provided in the same shape as each of the contact protrusions 742A to 742I.

As shown in the internal gear 74J, the fewer the contact convex portions 740 provided on the end surface 740J, the fewer the vibration propagation path to the contact surface portion 411, and the less the vibration from the internal gear 74J side to the second housing 40. transmission can be suppressed. Further, although the contact convex portions 742, 742A to 742J of the internal gears 74, 74A to 74J are arranged on the end surfaces 740, 740A to 740J, respectively, at equal intervals in the circumferential direction, the present invention is not limited to this.

<Modification example 11 of internal gear>
An internal gear 74K as a modification 10 of the internal gear 74 shown in FIG. 28 has contact convex portions 742K protruding from an end surface (opening end surface) 740K at irregular intervals in the circumferential direction on the other side. Note that in the internal gear 74K in Modification 10, the contact convex portion 742K is formed in a hemispherical shape similar to the contact convex portion 740, but the contact convex portions of each of the internal gears 74A to 74I are not limited to this. It may have the same shape as 742A to 742I.

<Modification example 12 of internal gear>
In comparison with the internal gear 74, an internal gear 74L as a modified example 11 of the internal gear 74 shown in FIG. Also includes a contact protrusion 742L. A plurality of contact protrusions 742L are protruded from both sides of the end faces 740L and 741L at predetermined intervals (equal intervals in this embodiment) in the circumferential direction. That is, the internal gear 74L is provided with a protruding contact convex portion (one side contact portion) similar to the contact convex portion 742L on one end surface (open end surface) 741L.

The internal gear 74L has a contact convex portion 742L in point contact with the contact surface portion 411 of the second housing 40 on the other end surface 740L side, and a contact convex portion 742L on the one end surface 741L side through the contact convex portion 742L. point contact with the first housing 30.

Thereby, the internal gear 74L is also connected to the motor side through point contact, and transmission of vibrations to the housing and the motor in the actuator can be suppressed. Note that the configuration in which contact convex portions are provided on each of the opening end surfaces of the internal gear 74 that are spaced apart in the axial direction can be applied to any of the internal gears 74A to 74K of each modification example 1 to 10, and has the above-mentioned effects. Therefore, the same effects as the internal gear 74L can be obtained.

In the internal gears 74, 74A to 74C, and 74E to 74L shown in the present embodiment and Modifications 1 to 11, the contact convex portions 742, 742A to 742C, and 742E to 742L have a cross section orthogonal to the axial direction toward the protruding direction. It is formed to have a small area. That is, the contact convex portions 742, 742A to 742C, 742E to 742L are configured such that the cross-sectional area perpendicular to the axial direction becomes smaller as the distance from the other end surface (opening end surface) 740, 740A to 740C, 740E to 740L increases. In addition, with the respective contact convex portions 742, 742A to 742C, and 742E to 742L in point contact with the contact surface portion 411, the internal gears 74, 74A to 74C, and 74E to 74L are connected to the first housing 30 and the second housing 30. It is held within a housing 40. Thereby, transmission of vibration from the internal gears 74, 74A to 74C, and 74E to 74L to the first housing 30 and the second housing 40 via the contact surface portion 411 can be suppressed.

Moreover, although the case where the separation structure of the internal gear and the housing is used as part of a planetary gear mechanism has been described, its use is not limited and it may be used as part of other gear mechanisms.

Further, in the above embodiment, the planetary gear mechanism of the planetary gear device is realized using three planetary gears, but the present invention is not limited to this. In the present invention, for example, a planetary gear mechanism using one or a plurality of planetary gears other than three may be employed to realize a planetary gear device.

Further, the planetary gear device to which the present invention is applied can be applied to various machines and devices that use reduction gears and speed increasers, such as automobiles, robots, industrial machines, and play equipment.

Further, in the above embodiment, the movement regulating convex part (first convex part) and the pair of stoppers (second convex part) are in line contact along the axial direction, so that movement inside the housing is restricted. Alternatively, a structure may be adopted in which the movement within the housing is restricted by point contact between the movement regulating convex portion (first convex portion) and the pair of stoppers (second convex portion). More specifically, the pair of stoppers (second convex portions) 45 in FIG. 5 may have a shape that exists intermittently in the axial direction, and the movement limiting convex portions (first convex portions) in FIG. 75 may exist intermittently in the axial direction.

1 Actuator 10 Motor 11 Motor body 12 Rotating shaft 20 Planetary gear device 30 First housing 30a Opening 40 Second housing 41 First part 42 Second part 43 Third part 43a Opening 44 Cylindrical body 44a Inner wall 45 Stopper (second convex part )
45a Standing portion 45b Connection portion 45c Top portion 46 Cylindrical body 47 Internal tooth portion 50 Housing 60 Planetary gear mechanism 70 First planetary gear mechanism 71 Sun gear 71a Sun tooth portion 72 Planet gear 72a Planet tooth portion 73 Carrier 73a Accommodating openings 74, 74A, 74B, 74C, 74D, 74E, 74F, 74G, 74H, 74I, 74J, 74K, 74L Internal gear 74a Internal toothed portion 74b Outer peripheral surface 75 Movement limiting convex portion (first convex portion)
75a Oblique side portion 75b Top portion 75c Notch portion 76 Pin 80 Second planetary gear mechanism 81 Sun gear 81a Sun tooth portion 82 Planet gear 82a Planet tooth portion 83 Carrier 84 Gear holding portion 84a Accommodating opening 85 Output shaft holding portion 85a Fitting hole 86 Output shaft 86a Output gear 87 Pin 90 Contact area 140 Second housing 141 Concave portion 174 Internal gear 175 Movement limiting convex portion (first convex portion)
411 Contact surface 740, 740A, 740B, 740C, 740D, 740E, 740G, 740G, 740H, 740J, 741L opening ends 742, 742A, 742C, 742D, 742D, 742D, 742D, 742D. 2F, 742g, 742H, 742I, 742J, 742K, 742L Contact convex portion 7421 inner surface

Claims (15)

an inner circumferential surface on which internal teeth are formed; an outer circumferential surface on which a convex portion is formed in at least a portion of the direction from one side to the other in the axial direction; and the inner circumferential surface at the other end. an internal gear having an open end surface extending between the outer circumferential surface and the outer peripheral surface;
a cylindrical housing that accommodates the internal gear and limits circumferential movement of the internal gear inside the housing by contacting a convex portion of the internal gear;
has
The housing has a contact surface portion provided opposite to the open end surface on the other side of the internal gear,
The opening end surface on the other side has a contact portion protruding toward the contact surface portion side,
The contact portion contacts the contact surface portion in the axial direction, thereby restricting movement of the internal gear toward the contact surface portion.
Separation structure between internal gear and housing. The contact portion includes at least three contact convex portions that make point contact with the contact surface portion.
A separation structure between an internal gear and a housing according to claim 1. A plurality of the contact portions protrude from the opening end surface at equal intervals in the circumferential direction,
The internal gear and housing separation structure according to claim 2. A plurality of the contact portions protrude from the opening end surface at unequal intervals in the circumferential direction,
The internal gear and housing separation structure according to claim 2. The contact portion is configured such that a cross-sectional area perpendicular to the axial direction becomes smaller as the distance from the opening end surface on the other side increases.
The internal gear and housing separation structure according to any one of claims 1 to 4. The contact portion is a cone whose apex is the tip on the side of the contact surface portion.
A separation structure between an internal gear and a housing according to any one of claims 1 to 5. The contact portion has a tip portion of the contact surface portion having a spherical shape.
A separation structure between an internal gear and a housing according to any one of claims 1 to 5. The contact portion includes a rod-shaped extension portion extending from the opening end surface toward the contact surface portion;
and a hemispherical part provided at the tip of the extending part,
A separation structure between an internal gear and a housing according to any one of claims 1 to 4. The contact portion has a cross-shaped cross section perpendicular to the axial direction.
The internal gear and housing separation structure according to any one of claims 1 to 5. The opening end surface on the one side of the internal gear is provided with a contact portion on one side that protrudes similarly to the contact portion.
The internal gear and housing separation structure according to any one of claims 1 to 9. The internal gear and the housing are made of synthetic resin,
The internal gear is made of a synthetic resin having a lower hardness than the synthetic resin forming the housing.
A separation structure between an internal gear and a housing according to any one of claims 1 to 10. A separation structure between an internal gear and a housing according to any one of claims 1 to 11,
one or more planetary gears meshing with the internal gear;
a sun gear located at the center of the one or more planetary gears and meshing with the one or more planetary gears;
a carrier rotatably supporting the one or more planetary gears;
Planetary gear system. a second sun gear that rotates in the same manner as the carrier rotates as the carrier rotates;
one or more second planetary gears disposed around the second sun gear and meshing with the second sun gear;
a second carrier rotatably supporting the one or more second planetary gears;
further comprising a second housing having internal teeth formed on the inner circumferential surface that mesh with the one or more second planetary gears,
the housing and the second housing are integrally molded;
The planetary gear system according to claim 12. sun gear and
one or more planetary gears arranged around the sun gear and meshing with the sun gear;
A planetary gear device comprising at least two stages of a planetary gear mechanism including a carrier rotatably supporting the one or more planetary gears,
Of the at least two stages of the planetary gear mechanism, the planetary gear mechanism that operates at the highest speed is provided with the separation structure between the internal gear and the housing according to any one of claims 1 to 11, and the planetary gear mechanism operates at the highest speed. The one or more planetary gears of the mechanism and the internal gear are in mesh with each other,
Of the at least two-stage planetary gear mechanism, the planetary gear mechanism that operates at the lowest speed includes a housing in which internal teeth are formed on the inner peripheral surface to mesh with the one or more planetary gears of the planetary gear mechanism. ,
Planetary gear system. The planetary gear device according to any one of claims 12 to 14,
a motor connected to the planetary gear device and driving the planetary gear device;
actuator.

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