Gear reducer and geared motor

Abstract

To provide a small-sized reduction gear which can lock an input from an output side, and a geared motor.SOLUTION: A lock part has: an input body having an input plate part, and rotating around a center axial line accompanying the revolution-rotation of a planetary gear; an output body having an output plate part opposing the input plate part in an axial direction; a connecting part for connecting the input body and the output body with a clearance in a peripheral direction; and a plate spring. A recess having a first inside face oriented to one side in the peripheral direction and a second inside face oriented to the other side in the peripheral direction is formed at an outer edge of the input plate part. A protrusion having a first outside face oriented to one seat in the peripheral direction and a second outside face oriented to the other side in the peripheral direction is formed at an outer edge of the output plate part. The plate spring has a circular-arc shaped circular arc part extending along an internal peripheral face of a case, a first claw part located at an end part of the circular arc part at one side in the peripheral direction, and a second claw part located at an end part of the circular arc part at the other side in the peripheral direction. The first claw part opposes the first inside face and the second outside face. The second claw part opposes the second inside face and the first outside face.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a reduction gear and a geared motor.

Background Art

[0002] For a drive device that requires high torque, a geared motor in which a planetary gear mechanism as a reduction gear is connected to a motor serving as a power source is adopted. Further, the reduction gear of Patent Document 1 discloses a braking reduction mechanism that does not allow power transmission from the output shaft to the motor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a conventional reduction gear, the protrusions and locking pieces for applying the brake also function as a power transmission path. Therefore, a large force is applied to the protrusions and locking pieces, and there is a problem that the reduction gear becomes large in size in order to suppress damage.

[0005] One aspect of the present invention aims to provide a reduction gear that can lock the input from the output side and can be miniaturized, and a geared motor.

Means for Solving the Problems

[0006] A reduction gear according to one aspect of the present invention comprises a sun gear that rotates about a central axis, a plurality of planetary gears that mesh with the sun gear, a locking part that supports the plurality of planetary gears so that they can revolve and rotate around the central axis, an internal gear that meshes with the planetary gears, and a cylindrical case that fixes the internal gear in the circumferential direction with respect to the central axis. The locking part comprises an input body having an input plate portion arranged along a plane perpendicular to the central axis and rotating about the central axis in accordance with the revolving rotation of the planetary gears, an output body having an output plate portion facing the input plate portion in the axial direction, a connecting part that connects the input body and the output body with a gap in the circumferential direction, and a leaf spring that is initially compressed and positioned between the outer edges of the input plate portion and the output plate portion and the inner circumferential surface of the case. The outer edge of the input plate portion is provided with a recess having a first inner surface facing one side in the circumferential direction and a second inner surface facing the other side in the circumferential direction. The outer edge of the output plate portion is provided with a convex portion having a first outer surface facing one side in the circumferential direction and a second outer surface facing the other side in the circumferential direction. The leaf spring has an arc-shaped arc portion extending along the inner circumferential surface of the case, a first claw portion located at one end of the arc portion in the circumferential direction, and a second claw portion located at the other end of the arc portion in the circumferential direction. The first claw portion faces the first inner surface and the second outer surface in the circumferential direction. The second claw portion faces the second inner surface and the first outer surface in the circumferential direction.

[0007] A geared motor according to one aspect of the present invention comprises the reduction gear described above and a motor unit connected to the reduction gear. [Effects of the Invention]

[0008] According to one aspect of the present invention, a miniaturized reduction gear and a geared motor are provided that can lock the input from the output side. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is an exploded perspective view of a geared motor according to one embodiment. [Figure 2] Figure 2 is a cross-sectional view of the locking mechanism in one embodiment. [Figure 3] Figure 3 is a magnified view of a portion of Figure 2. [Figure 4] Figure 4 is a cross-sectional view showing the power transmission process of the locking mechanism 32 in one embodiment. [Figure 5] Figure 5 is a cross-sectional view showing the locking function of the locking part of one embodiment. [Modes for carrying out the invention]

[0010] Hereinafter, a geared motor according to an embodiment of the present invention will be described with reference to the drawings. Note that the scope of the present invention is not limited to the following embodiments, and can be arbitrarily modified within the scope of the technical concept of the present invention.

[0011] The drawing shows the Z-axis parallel to the central axis J. In the following description, unless otherwise specified, the Z-axis direction will simply be referred to as the "axial direction" or "up and down direction," the +Z side as the "one axial side" or "upper side," and the -Z side as the "other axial side" or "downward side." Note that the up and down direction in this specification is a direction set for the convenience of explanation and does not limit the orientation when the geared motor is used. Furthermore, in the following description, the circumferential direction around the central axis J will simply be referred to as the "circumferential direction," and the radial direction with respect to the central axis J will simply be referred to as the "radial direction."

[0012] The arrows θ shown in the diagrams indicate the circumferential direction. In the following explanation, the side pointed to by arrow θ (+θ side) will be referred to as "one side of the circumferential direction," and the side opposite to the direction pointed to by arrow θ (-θ side) will be referred to as "the other side of the circumferential direction."

[0013] <Geared Motor> Figure 1 is an exploded perspective view of the geared motor 1. The geared motor 1 comprises a motor unit 2 and a reduction gear 3 connected to the motor unit 2. The parts of the geared motor 1 will be described in detail below.

[0014] <Motor section> The motor unit 2 has a motor shaft 22 that extends axially around the central axis J. The motor shaft 22 protrudes upward from the motor unit 2. The motor shaft 22 rotates around the central axis J. A first sun gear 33a is fixed to the upper end of the motor shaft 22. The motor unit 2 is connected to the reduction gear 3.

[0015] <Deceleration device> The reduction gear 3 is located above the motor unit 2. The reduction gear 3 reduces the power output from the motor unit 2.

[0016] The reduction gear 3 comprises a first planetary gear mechanism 30A, a second planetary gear mechanism 30B, and a third planetary gear mechanism 30C. The first planetary gear mechanism 30A, the second planetary gear mechanism 30B, and the third planetary gear mechanism 30C are arranged in this order from bottom to top. That is, the reduction gear 3 has a plurality of planetary gear mechanisms 30A, 30B, and 30C connected to each other along the axial direction. Power output from the motor unit 2 is transmitted in the order of the first planetary gear mechanism 30A, the second planetary gear mechanism 30B, and the third planetary gear mechanism 30C, and output at the output shaft 36c of the third planetary gear mechanism 30C.

[0017] The reduction gear 3 includes a cylindrical case 40, a first sun gear 33a, three first planetary gears 33b, a first internal gear 33c, a first carrier 31, three second planetary gears 34b, a second internal gear 34c, a second carrier (carrier, locking part) 32, three third planetary gears 35b, a third internal gear 35c, and a third carrier 36. The first carrier 31 also has a second sun gear 31c. Similarly, the second carrier 32 has a third sun gear 32c.

[0018] The first sun gear 33a, the first planetary gear 33b, the first carrier 31, and the first internal gear 33c constitute a first planetary gear mechanism 30A. The second sun gear 31c, the second planetary gear 34b, the second carrier 32, and the second internal gear 34c constitute a second planetary gear mechanism 30B. The third sun gear 32c, the third planetary gear 35b, the third carrier 36, and the third internal gear 35c constitute a third planetary gear mechanism 30C.

[0019] The case 40 has a cylindrical portion 41 and a bottom portion 42. The cylindrical portion 41 extends in the axial direction about the central axis J. The cylindrical portion 41 holds the first internal gear 33c, the second internal gear 34c, and the third internal gear 35c on the inner peripheral surface 41a and restricts rotation about the central axis J. That is, the cylindrical portion 41 fixes the first internal gear 33c, the second internal gear 34c, and the third internal gear 35c in the circumferential direction about the central axis J. The bottom portion 42 is located at the upper end of the cylindrical portion 41. A hole portion 43 is provided at the center of the bottom portion 42 when viewed from the axial direction. The hole portion 43 is circular about the central axis J. An output shaft 36c is inserted through the hole portion 43. A bearing for rotatably supporting the output shaft 36c may be held on the inner peripheral surface of the hole portion 43.

[0020] The first sun gear 33a extends in the axial direction about the central axis J. The first sun gear 33a is fixed to the motor shaft 22 and rotates about the central axis J together with the motor shaft 22.

[0021] The first internal gear 33c is annular about the central axis J. The first internal gear 33c surrounds the first sun gear 33a from the radially outer side. A gap for arranging the first planetary gear 33b is provided between the first internal gear 33c and the first sun gear 33a. The first internal gear 33c meshes with the first planetary gear 33b. The first internal gear 33c is fixed to the inner peripheral surface 41a of the cylindrical portion 41 of the case 40. The first internal gear 33c does not necessarily have to be fixed to the case 40 as long as its relative rotation with respect to the case 40 is restricted. Also, the first internal gear 33c may be integrally formed with the case 40.

[0022] The three first planetary gears 33b are arranged at equal intervals in the circumferential direction of the central axis J. In the radial direction, the three first planetary gears 33b are positioned between the first sun gear 33a and the first internal gear 33c. The three first planetary gears 33b mesh with the first sun gear 33a and the first internal gear 33c. The three first planetary gears 33b revolve around the central axis J as the first sun gear 33a rotates. A retaining hole opening upwards is provided in the center of each first planetary gear 33b.

[0023] The first carrier 31 has a first disc portion 31b, three first sub-shafts 31a, and a second sun gear 31c. The first disc portion 31b is disc-shaped with respect to the central axis J. The first disc portion 31b is located below the second planetary gear 34b and above the first planetary gear 33b. The first disc portion 31b is connected to the second sun gear 31c. The first disc portion 31b is located above the first sun gear 33a and the first planetary gear 33b. The three first sub-shafts 31a extend downward from the first disc portion 31b. The second sun gear 31c extends upward from the first disc portion 31b with respect to the central axis J.

[0024] The first sub-shaft 31a is inserted into the holding hole of the first planetary gear 33b. Each of the three first sub-shafts 31a rotatably supports the first planetary gear 33b. In other words, the first carrier 31 rotatably supports the multiple first planetary gears 33b from above (one side in the axial direction). The first carrier 31 rotates about the central axis J in accordance with the orbital rotation of the three first planetary gears 33b. In other words, the first carrier 31 supports the multiple first planetary gears 33b so that they can orbit and rotate around the central axis J.

[0025] The second solar gear 31c is located below (on the other axial side of) the third solar gear 32c and inside the second internal gear 34c. The second solar gear 31c extends axially about the central axis J. Since the second solar gear 31c is part of the first carrier 31, it rotates about the central axis J in accordance with the orbital rotation of the first planetary gear 33b.

[0026] The second internal gear 34c is annular in shape with respect to the central axis J. The second internal gear 34c surrounds the second sun gear 31c from the radially outer side. A gap is provided between the second internal gear 34c and the second sun gear 31c for arranging the second planetary gear 34b. The second internal gear 34c meshes with the second planetary gear 34b. The second internal gear 34c is fixed to the inner circumferential surface 41a of the cylindrical portion 41 of the case 40. The second internal gear 34c does not necessarily have to be fixed to the case 40, as long as its relative rotation to the case 40 is restricted. Alternatively, the second internal gear 34c may be integrally molded with the case 40.

[0027] The three second planetary gears 34b are arranged at equal intervals in the circumferential direction of the central axis J. In the radial direction, the three second planetary gears 34b are positioned between the second sun gear 31c and the second internal gear 34c. The three second planetary gears 34b mesh with the second sun gear 31c and the second internal gear 34c. The three second planetary gears 34b revolve and rotate in the circumferential direction of the central axis J as the second sun gear 31c rotates. A retaining hole 34ba opening upwards is provided in the center of the second planetary gear 34b.

[0028] The second carrier 32 includes an input body 50, an output body 60, a leaf spring 70, and a connecting portion 80. The second carrier 32 transmits power received from the second planetary gear 34b in the input body 50 to the output body 60 via the connecting portion 80. The second carrier 32 also functions as a locking mechanism that restricts the transmission of torque from the output body 60 to the input body 50. The function of the second carrier 32 as a locking mechanism will be described in detail later.

[0029] The connecting portion 80 of the second carrier 32 has a shaft portion 81 fixed to the input body 50. The shaft portion 81 has a second sub-shaft portion 81b extending downward from the input body 50. The second sub-shaft portion 81b is inserted into the holding hole 34ba of the second planetary gear 34b. The three second sub-shaft portions 81b each rotatably support the second planetary gear 34b. In other words, the second carrier 32 supports the multiple second planetary gears 34b so that they can revolve and rotate around the central axis J. That is, the second carrier 32 rotatably supports the multiple second planetary gears 34b from above (one side in the axial direction). The second carrier 32 rotates about the central axis J in accordance with the revolving rotation of the three second planetary gears 34b.

[0030] The output body 60 of the second carrier 32 is provided with a third solar gear 32c. That is, the second carrier 32 has a third solar gear 32c. The third solar gear 32c extends upward with respect to the central axis J.

[0031] The third sun gear 32c is positioned inside the third internal gear 35c. The third sun gear 32c extends axially about the central axis J. The third sun gear 32c rotates about the central axis J in accordance with the orbital rotation of the second carrier 32.

[0032] The third internal gear 35c is annular in shape with respect to the central axis J. The third internal gear 35c surrounds the third sun gear 32c from the radially outer side. A gap is provided between the third internal gear 35c and the third sun gear 32c for arranging the third planetary gear 35b. The third internal gear 35c meshes with the third planetary gear 35b. The third internal gear 35c is fixed to the inner circumferential surface 41a of the cylindrical portion 41 of the case 40. The third internal gear 35c does not necessarily have to be fixed to the case 40, as long as its relative rotation to the case 40 is restricted. Alternatively, the third internal gear 35c may be integrally molded with the case 40.

[0033] The three third planetary gears 35b are arranged at equal intervals in the circumferential direction of the central axis J. In the radial direction, the three third planetary gears 35b are positioned between the third sun gear 32c and the third internal gear 35c. The three third planetary gears 35b mesh with the third sun gear 32c and the third internal gear 35c. The three third planetary gears 35b revolve and rotate in the circumferential direction of the central axis J as the third sun gear 32c rotates. A retaining hole 35ba opening upwards is provided in the center of the third planetary gear 35b.

[0034] The third carrier 36 has a third disc portion 36b, three third sub-shafts 36a, and an output shaft 36c. The third disc portion 36b is disc-shaped with respect to the central axis J. The third disc portion 36b is located above the third solar gear 32c and the third planetary gear 35b. The three third sub-shafts 36a extend downward from the third disc portion 36b. The output shaft 36c extends upward from the third disc portion 36b with respect to the central axis J.

[0035] The third sub-shaft 36a is inserted into the holding hole 35ba of the third planetary gear 35b. The three third sub-shafts 36a each rotatably support the third planetary gear 35b. In other words, the third carrier 36 rotatably supports the multiple third planetary gears 35b from above (one side in the axial direction). The third carrier 36 rotates about the central axis J as the three third planetary gears 35b orbit and rotate. In other words, the third carrier 36 supports the multiple third planetary gears 35b so that they can orbit and rotate around the central axis J.

[0036] Since the output shaft 36c is part of the third carrier 36, it rotates around the central axis J in accordance with the orbital rotation of the third planetary gear 35b. The output shaft 36c is cylindrical with respect to the central axis J. The output shaft 36c is inserted through the hole 43 in the case 40 and protrudes upward from the upper end of the case 40.

[0037] <Rock Club> Next, the function of the second carrier 32 as a locking unit will be explained. In the following explanation, the second carrier 32 will be referred to as the locking unit 32. The locking unit 32 receives the torque output from the motor unit 2 from the second planetary gear 34b and transmits it to the subsequent planetary gear mechanism 30C via the third sun gear 32c. On the other hand, the locking unit 32 receives the torque input from the output shaft 36c via the third sun gear 32c, but restricts its transmission to the second planetary gear 34b. This protects the motor unit 2 and restricts the free rotation of the output shaft 36c.

[0038] The locking mechanism 32 is located inside the case 40. The locking mechanism 32 includes an input body 50, an output body 60, a connecting part 80, and a leaf spring 70.

[0039] The input body 50 rotates around the central axis J in accordance with the orbital rotation of the second planetary gear 34b. The input body 50 has a plate-shaped input plate portion 51.

[0040] The input plate portion 51 is arranged along a plane perpendicular to the central axis J. The outer edge 51e of the input plate portion 51 is provided with a recess 53 that is recessed radially inward. The input plate portion 51 is also provided with a plurality of support holes 51h (three in this embodiment) that penetrate in the axial direction. The plurality of support holes 51h are arranged at equal intervals along the circumferential direction. The shaft portion 81 of the connecting portion 80 is press-fitted and fixed into the support holes 51h.

[0041] The output unit 60 rotates together with the input unit 50 around the central axis J due to the torque transmitted from the input unit 50. The output unit 60 has an output plate section 61 and a third sun gear 32c. The output unit 60 transmits power to the subsequent planetary gear mechanism 30C at the third sun gear 32c.

[0042] The output plate portion 61 is arranged along a plane perpendicular to the central axis J. The output plate portion 61 faces the input plate portion 51 in the axial direction. The outer edge 61e of the output plate portion 61 is provided with a convex portion 63 that protrudes radially outward. The output plate portion 61 is also provided with a plurality of holes 82 (three in this embodiment) that penetrate in the axial direction. The plurality of holes 82 are arranged at equal intervals along the circumferential direction. Each hole 82 may be an elongated hole that extends in an arc shape along the circumferential direction. The shaft portion 81 of the connecting portion 80 is inserted into the holes 82.

[0043] Figure 2 is a cross-sectional view of the locking section 32 as seen from the axial direction. Note that the third sun gear 32c is shown in a simplified form in Figure 2. The input plate section 51 and the output plate section 61 are located inside the case 40. The outer diameters of the input plate section 51 and the output plate section 61 are smaller than the inner diameter of the cylindrical section 41 of the case 40. Also, the outer diameter of the output plate section 61 is smaller than the outer diameter of the input plate section 51. Therefore, the outer edge 61e of the output plate section 61 is located radially inward from the outer edge 51e of the input plate section 51.

[0044] Figure 3 is a magnified view of a portion of Figure 2. The recess 53 of the input plate portion 51 has a bottom surface 53c facing radially outward, a first inner surface 53a facing one side in the circumferential direction (+θ side), and a second inner surface 53b facing the other side in the circumferential direction (-θ side). The bottom surface 53c is arc-shaped with the central axis J as its center. The radius of the bottom surface 53c is approximately equal to the radius of the outer edge 61e of the output plate portion 61.

[0045] The projection 63 of the output plate portion 61 has a tip surface 63c facing radially outward, a first outer surface (63a) facing one side in the circumferential direction (+θ side), and a second outer surface 63b facing the other side in the circumferential direction (-θ side). The tip surface 63c of the projection 63 is an arc-shaped surface centered on the central axis J. The tip surface 63c faces the inner circumferential surface 41a of the case 40 in the radial direction. The radius of the tip surface 63c is about the radial length of the leaf spring 70, which is greater than the radius of the outer edge 51e of the input plate portion 51.

[0046] The convex portion 63 overlaps with the recess 53 of the input plate portion 51 when viewed from the axial direction. When viewed from the axial direction, the first inner surface 53a of the recess 53 and the second outer surface 63b of the convex portion 63 are positioned opposite each other with a gap in between. Also, when viewed from the axial direction, the second inner surface 53b of the recess 53 is positioned opposite the first outer surface 63a of the convex portion 63 with a gap in between. The input plate portion 51 and the output plate portion 61 are flat plates with different axial positions from each other, and the inner surface of the recess 53 and the outer surface of the convex portion 63 do not have to face each other in the circumferential direction. Alternatively, the convex portion 63 of the output plate portion 61, which extends in the axial direction, may fit into the recess 53 of the input plate portion 51, or the walls on both sides of the recess 53 of the input plate portion 51 may extend in the axial direction, and the inner surface of the recess 53 and the outer surface of the convex portion 63 may face each other in the circumferential direction.

[0047] As shown in Figure 2, the connecting portion 80 connects the input body 50 and the output body 60 with a gap in the circumferential direction. The rotation of the input body 50 is absorbed by the circumferential gap of the connecting portion 80 and then transmitted to the output body 60. The locking portion 32 has a plurality of (three in this embodiment) connecting portions 80. The plurality of connecting portions 80 are arranged at equal intervals along the circumferential direction. Each connecting portion 80 has a shaft portion 81 fixed to the input plate portion 51 and a hole 82 provided in the output plate portion 61. The shaft portion 81 is inserted into the hole 82.

[0048] The shaft portion 81 is cylindrical. The radial width of the hole 82 is slightly larger than the diameter of the shaft portion 81. On the other hand, the circumferential length of the hole 82 is greater than the diameter of the shaft portion 81. That is, the hole 82 in this embodiment is an elongated hole that extends along the circumferential direction. The shaft portion 81 is movable in the circumferential direction inside the hole 82. When the input body 50 rotates about the central axis J, the shaft portion 81 absorbs the circumferential gap inside the hole 82 and then contacts the inner surface of the hole 82. After contacting the inner surface of the hole 82, the shaft portion 81 transmits the torque of the input body 50 to the output body 60.

[0049] The leaf spring 70 is plate-shaped with its thickness in a direction perpendicular to the axial direction. The leaf spring 70 extends circumferentially with a uniform width dimension (a dimension along the axial direction of the central axis J). When viewed radially, the leaf spring 70 is positioned to overlap with the input plate portion 51 and the output plate portion 61. The leaf spring 70 has an arc portion 73, a first claw portion 71 on one circumferential side of the arc portion 73, and a second claw portion 72 on the other side. The diameter of the circle tangent to the outer surface of the arc portion 73 in a free state is larger than the inner diameter of the inner circumferential surface 41a of the case 40.

[0050] The leaf spring 70 is positioned with initial compression applied between the outer edges of the input plate portion 51 and the output plate portion 61 and the inner circumferential surface 41a of the case 40 such that the diameter of the arc portion 73 becomes smaller.

[0051] The arc portion 73 is arc-shaped and extends along the inner circumferential surface 41a of the case 40. The arc portion 73 faces the inner circumferential surface 41a of the case 40 in the radial direction. In its initial state, the arc portion 73 contacts the inner circumferential surface 41a of the case 40 along its entire circumferential length. The arc portion 73 also faces the outer edge 51e of the input plate portion 51 and the outer edge 61e of the output plate portion 61 in the radial direction. That is, the arc portion 73 is positioned in the gap between the inner circumferential surface 41a of the case 40 and the outer edge 51e of the input plate portion 51, and in the gap between the inner circumferential surface 41a of the case 40 and the outer edge 61e of the output plate portion 61.

[0052] The first claw portion 71 is located at one end of the arc portion 73 in the circumferential direction (+θ side). The second claw portion 72 is located at the other end of the arc portion 73 in the circumferential direction (-θ side). The first claw portion 71 and the second claw portion 72 protrude radially inward from their respective ends of the arc portion 73.

[0053] As shown in Figure 3, when viewed from the axial direction, the first claw portion 71 is positioned between the first inner surface 53a and the second outer surface 63b. Therefore, in the circumferential direction, the first claw portion 71 faces the first inner surface 53a and the second outer surface 63b. Similarly, the second claw portion 72 is positioned between the second inner surface 53b and the first outer surface 63a. Therefore, in the circumferential direction, the second claw portion 72 faces the second inner surface 53b and the first outer surface 63a.

[0054] As shown in Figure 3, the first inner surface 53a and the second inner surface 53b of the recess 53 form a first angle α with respect to the central axis J. The first angle α is the angle that the recess 53 makes with respect to the central axis J. The first outer surface 63a and the second outer surface 63b of the convex portion 63 form a second angle β with respect to the central axis J. The second angle β is the angle that the convex portion 63 makes with respect to the central axis J. The circumferentially opposing surfaces of the first claw portion 71 and the second claw portion 72 form a third angle γi with respect to the central axis J. The circumferentially opposing surfaces of the first claw portion 71 and the second claw portion 72 form a fourth angle γo with respect to the central axis J. The third angle γi is the angle that the circumferentially opposing surfaces of the convex portion 63 of the pair of claw portions 71 and 72 make with respect to the central axis J. On the other hand, the fourth angle γo is the angle formed between the recesses 53 of the pair of claw portions 71 and 72 and the circumferentially facing surfaces with respect to the central axis J. The gap in the connecting portion 80 forms a fifth angle δ with respect to the central axis J. The fifth angle δ is the angle formed between the gap between the shaft portion 81 and the inner surface of the hole 82, which is formed on the other circumferential side of the shaft portion 81 when the shaft portion 81 is moved to one side in the circumferential direction within the hole 82 of the connecting portion 80. The fifth angle δ corresponds to the magnitude of the circumferential play when power is transmitted by the connecting portion 80.

[0055] In this embodiment, the first angle α is greater than the fourth angle γo. The fourth angle γo is greater than the third angle γi. The third angle γi is greater than the second angle β. The second angle β is greater than the fifth angle δ. That is, each angle satisfies the following relationship. α>γo>γi>β>δ

[0056] As shown in Figure 3, in the connecting portion 80, with the shaft portion 81 positioned in the center of the circumferential dimension of the hole 82, the convex portion 63 is positioned in the circumferential center of the concave portion 53. That is, with the shaft portion 81 positioned in the center of the circumferential dimension of the hole 82, the size of the circumferential gap between the first outer surface 63a and the second inner surface 53b is equal to the size of the circumferential gap between the second outer surface 63b and the first inner surface 53a. Therefore, the input body 50 and the output body 60 perform the same operation regardless of whether they rotate in one or the other circumferential direction.

[0057] (Power transmission from input to output) Figure 4 is a cross-sectional view of the locking mechanism 32 showing the process of power transmission from the input body 50 to the output body 60. In Figure 4, the rotation of the input body 50 is indicated by a dashed arrow, and the rotation of the output body 60 is indicated by a solid line. Here, we will explain the case where the input body 50 rotates in one direction (+θ) in the circumferential direction, but the locking mechanism 32 operates similarly even when the input body 50 rotates in the other direction (-θ) in the circumferential direction.

[0058] When the input body 50 rotates around the central axis J in one direction (+θ) in the circumferential direction, the multiple shaft portions 81 rotate along the circumferential direction with the input body 50. The shaft portions 81 move circumferentially inside the hole 82 of the output body 60 until they contact the region of the inner surface of the hole 82 facing the other direction (-θ) in the circumferential direction. When the shaft portions 81 contact the inner surface of the hole 82, the rotation of the input body 50 is transmitted to the output body 60, and the input body 50 and the output body 60 rotate together around the central axis J.

[0059] As the input body 50 rotates circumferentially in one direction (+θ) around the central axis J, the shaft portion 81 contacts the inner surface of the hole 82, and the first inner surface 53a of the recess 53 contacts the first claw portion 71 of the leaf spring 70. Furthermore, the input body 50 displaces the first claw portion 71 circumferentially in one direction (+θ) by the first inner surface 53a of the recess 53, compressing the arc portion 73 of the leaf spring 70 and reducing the outer diameter of the arc portion 73. As a result, a part of the arc portion 73 separates from the inner surface 41a of the case 40. The compression of the leaf spring 70 reduces the static and kinetic friction between the leaf spring 70 and the inner surface 41a of the case 40. As a result, the leaf spring 70 rotates together with the input body 50 around the central axis J while sliding against the inner surface 41a of the case 40 with little sliding resistance. According to this embodiment, when the locking unit 32 transmits power from the input unit 50 to the output unit 60, the leaf spring 70 is compressed, which reduces the energy loss associated with the sliding of the leaf spring 70 and improves the power transmission efficiency of the locking unit 32.

[0060] In the locking portion 32 of this embodiment shown in Figure 3, the difference between the first angle α, which is the angle formed by the recess 53, and the fourth angle γo, which is the angle formed by the opposite faces of the pair of claw portions 71 and 72, the difference between the third angle γi, which is the angle formed by the circumferentially opposing faces of the pair of claw portions 71 and 72, and the second angle β, which is the angle formed by the convex portion 63, and the fifth angle δ, which is the angle of the gap in the connecting portion 80, satisfy the following relationship. (α-γo)-δ<(γi-β)

[0061] Therefore, when the input body 50 rotates, the gap in the connecting portion 80 is completely absorbed before the first claw portion 71 and the second claw portion 72 of the leaf spring 70 come into contact with the second outer surface 63b and the first outer surface 63a of the protrusion 63, respectively, and power transmission at the connecting portion 80 begins. According to this embodiment, power can be transmitted from the input body 50 to the output body 60 by multiple shafts and holes provided around the central axis J.

[0062] Specifically, as shown in Figure 4, the first claw portion 71 of the leaf spring 70 is pressed against the first inner surface 53a of the recess 53 and rotates in one direction (+θ) in the circumferential direction. Since the third angle γi of the leaf spring 70 is greater than the second angle β of the convex portion 63, the second claw portion 72 does not come into contact with the first outer surface 63a of the convex portion, and the arc portion 73 of the leaf spring 70 is not pushed open by the convex portion 63. Therefore, it is possible to suppress the leaf spring 70 from being pressed against the inner circumferential surface 41a of the case 40.

[0063] (Restriction of power transmission from output to input) Figure 5 is a cross-sectional view of the locking section 32, showing how the power transmission from the output unit 60 to the input unit 50 is restricted and the locking function is activated. Here, we will describe the case where the output unit 60 rotates in one direction (+θ) in the circumferential direction, but the locking section 32 operates similarly even when the output unit 60 rotates in the other direction (-θ) in the circumferential direction.

[0064] When the output unit 60 attempts to rotate around the central axis J in one circumferential direction (+θ), the first outer surface 63a of the protrusion 63 displaces the first claw portion 71 of the leaf spring 70 in one circumferential direction (+θ), extending the arc portion 73 of the leaf spring 70 and pressing the outer surface of the arc portion 73 against the inner circumferential surface 41a of the case 40. As the leaf spring 70 is extended, the static friction force between the leaf spring 70 and the inner circumferential surface 41a of the case 40 increases, restricting the rotation of the leaf spring 70 relative to the case 40. Furthermore, as the rotation of the leaf spring 70 is restricted, the rotation of the output unit 60 is restricted by interference between the protrusion 63 and the first claw portion 71 of the leaf spring 70. As a result, the locking portion 32 restricts the transmission of power from the output unit 60 to the input unit 50.

[0065] As described above, in the locking portion 32 of this embodiment shown in Figure 3, the difference between the first angle α and the fourth angle γo, the difference between the third angle γi and the second angle β, and the fifth angle δ, which is the angle of the gap in the connecting portion 80, satisfy the following relationship. (α-γo)-δ<(γi-β)

[0066] Therefore, even when power is transmitted to the input body 50 by the rotation of the output body 60 and the input body 50 rotates, the protrusion 63 comes into contact with the first claw portion 71 or the second claw portion 72 of the leaf spring 70 during rotation, and the lock is activated. According to this embodiment, the transmission of power from the output body 60 to the input body 50 is obstructed and locked.

[0067] Specifically, as shown in Figure 5, even if the output body 60 rotates in one direction (+θ) in the circumferential direction, the first outer surface 63a of the protrusion 63 contacts the second claw 72 of the leaf spring 70 before the shaft 81 contacts the inner surface of the hole 82. As a result, the locking part 32 can press the leaf spring 70 against the inner circumferential surface 41a of the case 40 and lock it before the input body 50 and the output body 60 begin to rotate synchronously. This limits the rotation of the output body 60 and suppresses the transmission of torque from the output body 60 to the input body 50.

[0068] According to this embodiment, the torque applied from the input body 50 is transmitted between the shaft portion 81 of the connecting portion 80 and the inner surface of the hole 82. On the other hand, the torque applied from the output body 60 is transmitted from the protrusion 63 to the leaf spring 70, locking it and limiting its transmission to the input body 50. In other words, with the locking portion 32 of this embodiment, the power transmission path and the portion that performs the locking function are provided in different parts. Therefore, it is possible to suppress the concentration of load in one part of the locking portion 32, and by miniaturizing each part, the locking portion 32 can be made smaller. As a result, the reduction gear 3 can be made smaller.

[0069] The connecting portion 80 in this embodiment consists of a shaft portion 81 fixed to the input body 50 and a hole 82 provided in the output body 60. According to this embodiment, the connecting portion 80 has a simple structure, is easy to assemble, and can transmit a large torque from the input body 50 to the output body 60.

[0070] In this embodiment, the case in which the hole 82 is provided in the output plate portion 61 and the shaft portion 81 is fixed to the input plate portion 51 has been described. However, the hole 82 may be provided in the input plate portion 51 and the shaft portion 81 may be fixed to the output plate portion 61. That is, the hole 82 may be provided in one of the input plate portion 51 and the output plate portion 61, and the shaft portion 81 may be fixed to the other of the input plate portion 51 and the output plate portion 61. Furthermore, the configuration of the connecting portion 80 is not necessarily limited to this embodiment, as long as it connects the input body 50 and the output body with a gap in the circumferential direction. For example, instead of the shaft portion 81 and the hole 82, the recess of the input plate portion 51 and the convex portion of the output plate portion 61 may be arranged to face each other in the circumferential direction via a leaf spring 70.

[0071] In this embodiment, multiple connecting portions 80 are provided along the circumferential direction. According to this embodiment, the stress applied to each connecting portion 80 during the power transmission process from the input body 50 to the output body 60 can be reduced, and by miniaturizing each connecting portion 80, the locking portion 32 can be miniaturized.

[0072] As shown in Figure 1, according to this embodiment, the shaft portion 81 is fixed to the input plate portion 51 and inserted into the hole 82 on one axial side (upper side, +Z side) of the input plate portion 51. The shaft portion 81 also rotatably supports the second planetary gear 34b on the other axial side (lower side, -Z side) of the input plate portion 51. In other words, the shaft portion 81 in this embodiment acts as a connecting portion 80 and plays a part in the power transmission from the input body 50 to the output body 60. Furthermore, the shaft portion 81 acts as a second sub-shaft portion 81b and plays a part in the power transmission from the second planetary gear 34b to the input body 50. In this way, the torque transmitted from the second planetary gear 34b is transmitted to the output body 60 by the shaft portion 81. Therefore, the load on the input body 50 during the power transmission process can be reduced, and the input body 50 can be made smaller. Furthermore, by adopting such a structure, a high-strength material (e.g., a metal material) can be used for the shaft portion 81, allowing a lightweight material (e.g., a resin material) to be used for the input body 50. As a result, the weight of the reduction gear 3 can be reduced.

[0073] The reduction gear 3 of this embodiment has multiple planetary gear mechanisms 30A, 30B, and 30C, each having a sun gear, planetary gears, internal gears, and a carrier. Therefore, the reduction gear 3 can achieve a large reduction ratio.

[0074] Furthermore, the locking portion 32 of this embodiment functions as a carrier (second carrier 32) for one of the multiple planetary gear mechanisms 30A, 30B, and 30C (the second planetary gear mechanism 30B in this embodiment). According to this embodiment, by incorporating the locking portion 32 into a part of the second planetary gear mechanism 30B, the reduction gear 3 can be miniaturized.

[0075] The reduction gear 3 of this embodiment has three planetary gear mechanisms 30A, 30B, and 30C, and the locking part 32 functions as the middle carrier (second carrier 32) of the three carriers (third carrier 36, second carrier 32, and first carrier 31) arranged along the axial direction. The power of the motor unit 2 is reduced in the order of the first planetary gear mechanism 30A, the second planetary gear mechanism 30B, and the third planetary gear mechanism 30C. Therefore, the locking part 32 can be positioned at a point where torque and rotational speed are well balanced. As a result, it is possible to suppress excessive force being applied to the locking part 32 while also suppressing the speed of the locking part 32 from becoming too fast, thereby stabilizing the operation of the locking part 32.

[0076] Although embodiments and modifications of the present invention have been described above, the configurations and combinations thereof in the embodiments are merely examples, and additions, omissions, substitutions, and other modifications are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited by the embodiments.

[0077] For example, in the embodiments described above, the internal gear is fixed and the power input from the sun gear is output from the carrier in the planetary gear mechanisms 30A, 30B, and 30C. However, in the planetary gear mechanism used in the reduction gear, the internal gear, sun gear, and carrier may rotate relative to each other, and the input may come from any of them and the output from any of them. For example, the carrier may be fixed and the power input from the sun gear may be output from the internal gear. Alternatively, the mechanism may have a speed change mechanism that switches the output part to change the reduction ratio.

[0078] Furthermore, the above-described embodiment explained the case where the first angle α, second angle β, third angle γi, fourth angle γo, and fifth angle δ are angles of 180° or less. By using such an angle range, a reduction gear that can achieve the above-described effects with a simple configuration can be realized. However, the above angles may each be angles that exceed 180°. When the first angle α and the second angle β exceed 180°, the concave portion 53 will appear to be convex and the convex portion 63 will be concave, but even with such a configuration, the present invention is satisfied and the effects of the present invention can be obtained. Moreover, the third angle γi and the fourth angle γo may be angles that exceed 360°. In this case, the leaf spring 70 is wrapped around the input body 50 and the output body 60 at least once. [Explanation of symbols]

[0079] 1...Geared motor, 2...Motor section, 3...Reduction device, 30A...First planetary gear mechanism, 30B...Second planetary gear mechanism, 30C...Third planetary gear mechanism, 31...First carrier, 31c...Second sun gear, 32...Second carrier (carrier, lock section), 32c...Third sun gear, 33a...First sun gear, 33b...First planetary gear, 33c...First internal gear, 34b...Second planetary gear, 34c...Second internal gear, 35b …3rd planetary gear (planetary gear), 35c…3rd internal gear (internal gear), 36…3rd carrier (carrier), 40…case, 41a…inner surface, 50…input body, 51…input plate section, 51e, 61e…outer edge, 53…recess, 53a…1st inner surface, 53b…2nd inner surface, 60…output body, 61…output plate section, 63…convex section, 63a…1st outer surface, 63b…2nd outer surface, 70…leaf spring, 71…1st claw section, 72…2nd claw section, 73…arc section, 80…connecting section, 81…shaft section, 82…hole, J…central axis, α…1st angle, β…2nd angle, γi…3rd angle, γo…4th angle, δ…5th angle

Claims

1. A solar gear that rotates around its central axis, Multiple planetary gears that mesh with the aforementioned sun gear, A locking mechanism that supports multiple planetary gears so that they can revolve and rotate around the central axis, An internal gear that meshes with the aforementioned planetary gear, The system comprises a cylindrical case that fixes the internal gear in the circumferential direction, with the aforementioned central axis as the center, The aforementioned locking mechanism is An input body having an input plate portion arranged along a plane perpendicular to the central axis, which rotates about the central axis in conjunction with the orbital rotation of the planetary gear, An output unit having an input plate portion and an output plate portion facing each other in the axial direction, A connecting portion that connects the input body and the output body with a gap in the circumferential direction, The case has a leaf spring that is initially compressed and positioned between the outer edges of the input plate portion and the output plate portion and the inner circumferential surface of the case, The outer edge of the input plate portion is provided with a recess having a first inner surface facing one side in the circumferential direction and a second inner surface facing the other side in the circumferential direction. The outer edge of the output plate portion is provided with a convex portion having a first outer surface facing one side in the circumferential direction and a second outer surface facing the other side in the circumferential direction. The aforementioned leaf spring is An arc-shaped arc portion extending along the inner circumferential surface of the case, The first claw portion is located at one end of the circumferential direction of the arc portion, It has a second claw portion located at the other end of the arc portion in the circumferential direction, The first claw portion faces the first inner surface and the second outer surface in the circumferential direction, The second claw portion faces the second inner surface and the first outer surface in the circumferential direction, The aforementioned connecting portion is A hole extending circumferentially is provided in one of the input plate portion and the output plate portion, It has a shaft portion that is fixed to the other of the input plate portion and the output plate portion and inserted into the hole, The shaft portion is fixed to the input plate portion, inserted into the hole on one axial side of the input plate portion, and rotatably supports the planetary gear on the other axial side of the input plate portion, in the reduction gear.

2. The reduction gear according to claim 1, wherein the aforementioned connecting portion is provided in multiple locations along the circumferential direction.

3. A solar gear that rotates around its central axis, Multiple planetary gears that mesh with the aforementioned sun gear, A locking mechanism that supports multiple planetary gears so that they can revolve and rotate around the central axis, An internal gear that meshes with the aforementioned planetary gear, The system comprises a cylindrical case that fixes the internal gear in the circumferential direction, with the aforementioned central axis as the center, The aforementioned locking mechanism is An input body having an input plate portion arranged along a plane perpendicular to the central axis, which rotates about the central axis in conjunction with the orbital rotation of the planetary gear, An output unit having an input plate portion and an output plate portion facing each other in the axial direction, A connecting portion that connects the input body and the output body with a gap in the circumferential direction, The case has a leaf spring that is initially compressed and positioned between the outer edges of the input plate portion and the output plate portion and the inner circumferential surface of the case, The outer edge of the input plate portion is provided with a recess having a first inner surface facing one side in the circumferential direction and a second inner surface facing the other side in the circumferential direction. The outer edge of the output plate portion is provided with a convex portion having a first outer surface facing one side in the circumferential direction and a second outer surface facing the other side in the circumferential direction. The aforementioned leaf spring is An arc-shaped arc portion extending along the inner circumferential surface of the case, The first claw portion is located at one end of the circumferential direction of the arc portion, It has a second claw portion located at the other end of the arc portion in the circumferential direction, The first claw portion faces the first inner surface and the second outer surface in the circumferential direction, The second claw portion faces the second inner surface and the first outer surface in the circumferential direction, It has multiple planetary gear mechanisms connected to each other along the axial direction, Each of the multiple planetary gear mechanisms is, A sun gear that rotates about the aforementioned central axis, Multiple planetary gears that mesh with the aforementioned sun gear, An internal gear that meshes with the aforementioned planetary gear, It has a carrier that supports a plurality of the planetary gears so that they can revolve and rotate around the central axis, The locking portion is a reduction gear that functions as the carrier of any one of the planetary gear mechanisms.

4. It has three of the aforementioned planetary gear mechanisms, The reduction gear according to claim 3, wherein the locking portion functions as the middle carrier among the three carriers arranged along the axial direction.

5. The first inner surface and the second inner surface form a first angle α with respect to the central axis, The first outer surface and the second outer surface form a second angle β with respect to the central axis, The circumferentially opposing surfaces of the first claw portion and the second claw portion form a third angle γi with respect to the central axis. The surfaces of the first claw portion and the second claw portion facing opposite directions in the circumferential direction form a fourth angle γo with respect to the central axis. The gap in the connecting portion forms a fifth angle δ with respect to the central axis. Let the first angle be α. Let the second angle be β. Let the third angle be γi. Let the fourth angle be γo. A speed reduction device according to any one of claims 1 to 4, wherein, when the fifth angle is δ, each angle satisfies the following relationship. α > γo > γi > β > δ (α-γo)-δ<(γi-β)

6. The reduction gear according to claim 5, wherein the difference between the first angle and the second angle is greater than the fifth angle.

7. A reduction gear according to any one of claims 1 to 6, A geared motor having a motor section connected to the aforementioned reduction gear.

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