Gears, gear units and planetary gear units

Abstract

To provide a gear which can be produced in low cost and can smoothly engage with another gear.SOLUTION: A gear has a gear body 2 through which a through hole 3 for insertion of a shaft 110 is formed in an axial direction. The through hole 3 has an enlarged diameter part 5 radially enlarged from a position away from one end face 2a toward the one end face 2a.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a gear, a gear device, and a planetary gear device. [Background technology]

[0002] Conventionally, in gear devices used in various mechanical devices such as automobiles and robots, it is known that the teeth are crowned to ensure smooth meshing even if the teeth and bearings are deformed due to load or heat during gear operation, or even if there are manufacturing and assembly errors.

[0003] Crowning is a process in which the gear teeth are rounded toward the center, convex across the entire tooth width, and the tooth thickness gradually increases from both axial ends toward the axial center. This prevents the gear from having a bad tooth contact at the end of the tooth width, and concentrates the tooth contact at the center of the tooth width.

[0004] Patent document 1 discloses a planetary gear device in which the teeth of a sun gear, an internal gear arranged on the outer periphery of the sun gear and coaxial with the sun gear, and a planetary gear arranged between the sun gear and the internal gear so as to mesh with both, are crowned. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2003-130147 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, when gears have a unique tooth shape compared to spur gears, such as helical gears in which the tooth traces are twisted and spirally formed so as to extend in the tooth width direction, machining the teeth with high precision in the tooth width direction by crowning as described above increases the manufacturing cost. Therefore, there is a demand for gears that can smoothly mesh with other gears at low cost, even if there are deformations in the teeth or bearings, or machining and assembly errors.

[0007] The present invention has been made in consideration of the above-mentioned points, and an object of the present invention is to provide a gear, a gear device, and a planetary gear device that can smoothly mesh with other gears at low cost. [Means for solving the problem]

[0008] One embodiment of the gear of the present invention is as follows: a gear body having an insertion hole for inserting a shaft formed therethrough in the axial direction; The insertion hole is Both Away from the end face Each From the position On both ends Radially expands toward The first enlarged diameter portion and the second It has an enlarged diameter portion, When the shaft is inclined with respect to the insertion hole, the first enlarged diameter portion and the second enlarged diameter portion each make surface contact or line contact with the shaft. Adopt the configuration.

[0009] One embodiment of the gear device of the present invention is a gear device having the above-mentioned gears, The shaft; the gear body having the shaft inserted through the insertion hole; Have 、 before The first enlarged diameter portion and the second enlarged diameter portion each have a relatively small diameter portion and a relatively large diameter portion at different positions in the axial direction, and when the shaft is inclined with respect to the insertion hole, the shaft contacts the small diameter portion and enters a space radially outward of the small diameter portion at the large diameter portion.

[0010] One embodiment of the gear device of the present invention is 、 The gear body has an insertion hole for inserting a shaft formed therethrough in the axial direction, and the insertion hole has an enlarged diameter portion that radially expands in diameter from a position away from one end face in the axial direction toward the one end face.Has a pair of gears death, The shaft; a first gear of the pair of gears, the shaft of which is inserted through the insertion hole; a second gear of the pair of gears, the shaft of which is inserted through the insertion hole; having The first gear and the second gear are such that the enlarged diameter portions face in directions away from each other, The first gear and the second gear have a radially expanding diameter toward the one end faces separated from each other. They are arranged as follows: the enlarged diameter portion of the first gear and the enlarged diameter portion of the second gear each have a small diameter portion having a relatively small diameter and a large diameter portion having a relatively large diameter, at different positions in the axial direction, When the shaft is inclined with respect to the insertion hole, The enlarged diameter portion of the first gear and the enlarged diameter portion of the second gear are in surface contact or line contact with the shaft, and the shaft is Contact with each of the small diameter portions death In each of the large diameter portions, a configuration is adopted in which the large diameter portions enter into spaces radially outward of the corresponding small diameter portions.

[0011] One embodiment of the planetary gear device of the present invention has the gear device having the above-mentioned configuration, The gear is a planetary gear that is disposed between the sun gear and the internal gear and meshes with both of them, The shaft is configured to support the planetary gear so that it can revolve around the sun gear, and is a planetary shaft portion provided on a carrier that rotates based on the revolution of the planetary gear. Effect of the Invention

[0012] According to the present invention, the gear can be manufactured at low cost and can smoothly mesh with other gears. [Brief description of the drawings]

[0013] [Figure 1] 1 is an external perspective view of a gear according to an embodiment of the present invention; FIG. [Diagram 2] 1 is a vertical sectional view of a gear according to one embodiment of the present invention; [Diagram 3] 1 is a cross-sectional view showing a schematic state of use of a gear according to an embodiment of the present invention; [Figure 4] FIG. 2 is a diagram showing an example of a gear device using the gear. [Diagram 5] FIG. 2 is a diagram showing a state in which a gear device using the same gear is used. [Figure 6] FIG. 11 is an external perspective view of a modified example of a gear according to an embodiment of the present invention. [Figure 7] FIG. 11 is a cross-sectional view showing a schematic state of use of a modified example of the gear according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an external perspective view of a gear according to an embodiment of the present invention, and FIG. 2 is a vertical sectional view of the gear according to the embodiment of the present invention.

[0015] The gear 1 shown in Figures 1 and 2 has a gear body 2 with an insertion hole 3 for inserting a shaft formed therethrough in the axial direction, and the insertion hole 3 has an enlarged diameter portion 4 whose diameter radially increases from a position away from one end face (2a, 2b) in the axial direction toward the one end face (2a, 2b).

[0016] Gear 1 is a gear that rotates around a shaft 11 (see FIG. 3) that is inserted through insertion hole 3. Gear 1 may be, for example, a planetary gear disposed between a sun gear and an internal gear, or an idle gear that serves as an intermediate gear inserted between a driving gear and a driven gear.

[0017] The gear body 2 is a cylindrical body having teeth 22 on its outer periphery, and is an external gear. The teeth 22 may have, for example, helical teeth cut obliquely to the gear axis, or may have teeth whose tooth traces are straight and parallel to the axis. The gear 1 shown in Fig. 1 is, for example, a helical gear, and is formed by injection molding.

[0018] The insertion hole 3 is disposed in the center of the gear body 2. A shaft 11 (see FIG. 3), which is the center of rotation of the gear 1, is inserted into the insertion hole 3. The insertion hole 3 is surrounded by an inner circumferential surface having a diameter that allows the gear body 2 to freely rotate around the inserted shaft 11 (see FIG. 3).

[0019] The expanded diameter portion 4 has a first expanded diameter portion 5 and a second expanded diameter portion 6. The first expanded diameter portion 5 is formed in an axial direction so as to expand radially from a position 51 away from one end face 2a of the gear body 2 toward the one end face 2a. The second expanded diameter portion 6 is formed in an axial direction so as to expand radially from a position 61 away from the other end face 2b of the gear body 2 toward the other end face 2b.

[0020] The first enlarged diameter portion 5 and the second enlarged diameter portion 6 each have a small diameter portion 5a, 6a having a relatively small diameter and a large diameter portion 5b, 6b having a relatively large diameter at different positions in the axial direction.

[0021] The inner peripheral surfaces of the first enlarged diameter portion 5 and the second enlarged diameter portion 6 may be linear in cross section or curved in cross section. The first enlarged diameter portion 5 and the second enlarged diameter portion 6 have a surface that is more gently inclined than a chamfered surface. One end surface 2a of the gear 1 has a cylindrical protrusion 24 that is protruding so as to surround the insertion hole 3 and has a cutout portion that is partially cut out. The tip surface of the cylindrical protrusion 24 is a plane perpendicular to the axis. The cutout portion is provided with a cutout portion with the runner during molding, so that unnecessary foreign matter such as remaining cutouts of the runner do not protrude outward from the end surface of the gear 1. Furthermore, the cutout portion of the cylindrical projection 24 may function as an oil reservoir for storing lubricating oil for the planetary gears.

[0022] FIG. 3 is a cross-sectional view that typically shows a state in which a gear according to an embodiment of the present invention is used.

[0023] As shown in FIG. 3, in the first enlarged diameter portion 5 and the second enlarged diameter portion 6, when the shaft 11 is inclined relative to the insertion hole 3, the shaft 11 contacts the small diameter portion 5a and enters the space radially outward of the small diameter portion 5a in the large diameter portion 5b.

[0024] As a result, when the shaft 11 of the gear 1 is inclined relative to the insertion hole 3, the gear 1 comes into contact with the shaft 11 at each of the first enlarged diameter portion 5 and the second enlarged diameter portion 6, and is supported by the shaft 11 via these contact portions so as to be rotatable around the shaft 11.

[0025] The contact between gear 1 and shaft 11 is preferably surface contact, but may be line contact or point contact. In either case, it is preferable that gear 1 and shaft 11 contact each other at multiple points. This allows gear 1 to mesh with other gears that are adjacently arranged and connected to each other without applying a load to the other gears, even if shaft 11 is arranged at an angle during rotation.

[0026] Fig. 4 is a diagram showing an example of a gear device using the same gear. The gear device shown in Fig. 4 will be described as a planetary gear device 100 that uses gear 1 as a planetary gear, but it may be any gear device as long as it has a configuration including a gear through which a shaft is inserted.

[0027] 4 reduces the rotation input from a motor (not shown) at a predetermined reduction ratio and outputs the reduced rotation. The planetary gear device 100 has a housing 140 that accommodates a planetary gear mechanism as the gear mechanism 130, and a housing cover 150 that is disposed at one end of the housing 140 in the axial direction (one axial end).

[0028] The planetary gear device 100 is attached to, for example, a rotating shaft (drive shaft) 110 of a motor to constitute an actuator (not shown).

[0029] In this embodiment, the housing 140 accommodates the gear mechanism 130 having a first planetary gear mechanism 170 and a second planetary gear mechanism 180 arranged along the axial direction together with the housing cover 150, thereby realizing multiple stages of reduction in speed. In the housing 140, the gear mechanism 130 reduces the rotation of the rotating shaft 110 driven by the motor in two stages and outputs the rotation from the output shaft connection portion 187.

[0030] The housing 140 is a cylindrical body with an open end on one axial side (the left side in FIG. 4) to which the housing cover 150 is attached. The housing 140 has a cylindrical main body portion 145 to which a circular ring portion 146 having a support cylindrical portion 147 is joined at an end on the other axial side (the right side in FIG. 4).

[0031] The main body cylinder portion 145 accommodates, from one side to the other side in the axial direction, the first planetary gear mechanism 170 and the second planetary gear mechanism 180. The main body cylinder portion 145 accommodates the second planetary gear mechanism 180 with its output shaft connection portion 187 protruding from the other end portion of the main body cylinder portion 145 in the axial direction to the other side.

[0032] The inner peripheral surface of the main body tubular portion 145 engages with the outer peripheral surface of the first internal gear 174 of the first planetary gear mechanism 170 .

[0033] The main body cylinder portion 145 supports the first internal gear 174 in a floating state such that the axis of the first internal gear 174 is slightly inclined with respect to the central axis of the main body cylinder portion 145 (housing 140).

[0034] The main body cylinder portion 145 is provided with a second internal gear portion (not shown) having a plurality of teeth extending in the axial direction on the inner peripheral surface on the other side in the axial direction adjacent to the housing region that houses the first internal gear 174. The second internal gear portion is a helical gear, and meshes with the planetary gear 182 of the second planetary gear mechanism 180. Note that this second internal gear portion can also be regarded as the internal gear of the second planetary gear mechanism 180. Furthermore, this second internal gear portion may be a member separate from the main body cylinder portion 145, i.e., the housing 140, as the internal gear of the second planetary gear mechanism 180.

[0035] Housing cover 150 is an annular body, and has a central opening 151 in the center for arranging rotating shaft 110, which is a connecting shaft with the planetary gear mechanism (gears). Central opening 151 is arranged so as to be coaxial with the axis of sun gear 171 inside housing 140. Rotating shaft 110 is inserted into central opening 151.

[0036] The first planetary gear mechanism 170 includes a sun gear 171, a plurality of (for example, three) planetary gears 172 arranged around the sun gear 171 at the center, a first carrier 173 that rotatably supports the plurality of planetary gears 172, and a first internal gear 174. The gear 1 of this embodiment is applied to the planetary gear 172, and the shaft 11 is applied to a planetary shaft portion 173c of a carrier cover 1734 of the first carrier 173.

[0037] The sun gear 171 is an external gear with sun teeth formed on its outer circumferential surface, and is fixed to the rotating shaft 110 inserted into the planetary gear set 100 through the central opening 151. The sun gear 171 rotates coaxially with the rotating shaft 110 when driven by the motor. The sun gear 171 is, for example, a helical gear having spiral teeth cut obliquely with respect to the axis of the sun gear 171.

[0038] The planetary gear 172 is an external gear with a planetary teeth portion formed on its outer circumferential surface. The multiple planetary gears 172 are arranged at equal intervals between the sun gear 171 and the first internal gear 174, and mesh with both the sun gear 171 and the first internal gear 174. The multiple planetary gears 172 are arranged, for example, on the same circle centered on the axis of the first planetary gear mechanism 170, and are rotatably supported by the first carrier 173. The planetary teeth portion has, for example, helical teeth cut obliquely with respect to the axis of the planetary gear 172. The planetary gear 172 is a so-called helical gear.

[0039] The gear 1 of the first embodiment is applied to the planetary gear 172. That is, the planetary gear 172 has an insertion hole 3 through which the planetary shaft portion 173c (corresponding to the shaft 11) is inserted. The insertion hole 3 has a first enlarged diameter portion 5 and a second enlarged diameter portion 6 which radially enlarge in diameter from positions away from both end faces 2a in the axial direction toward both end faces 2a.

[0040] Each of the planetary gears 172 rotates about its own central axis (planetary shaft portion 173c) based on the rotation of the sun gear 171. Also, each of the planetary gears 172 revolves around the sun gear 171 based on its own rotation and meshing with the first internal gear 174. The central axis of revolution of the planetary gears 172 may coincide with the central axis of the sun gear 171.

[0041] The first carrier 173 rotatably supports the planetary gear 172. In addition, the first carrier 173 rotates based on the revolution of the planetary gear 172 and transmits the rotation to the second planetary gear mechanism 180.

[0042] The first carrier 173 is formed into a cylindrical shape by a carrier body 1732 and a carrier cover 1734 that engages with the carrier body 1732. An accommodation opening 173a is formed on the peripheral surface of the carrier body 1732, and the planetary gear 172 is rotatably supported in the accommodation opening 173a by a planetary shaft portion 173c that faces in the axial direction. A part of the planetary gear 172 protrudes radially outward through the accommodation opening 173a. As a result, the planetary teeth portion meshes with a first internal teeth portion 174a of the first internal gear 174.

[0043] The first carrier 173 rotatably houses the sun gear 171 and the planetary gears 172, and a sun gear 181 of a second planetary gear mechanism 180 is fixed to a carrier body 1732, the sun gear 181 rotating on the same axis as the sun gear.

[0044] The carrier cover 1734 is attached to the carrier body 1732 from one side in the axial direction. The carrier cover 1734 has an annular body 173b having a through hole in the center through which the rotating shaft 110 is inserted, and a planetary shaft portion 173c formed integrally with the annular body 173b and protruding therefrom. The planetary shaft portion 173c corresponds to the shaft 11 shown in FIG. 3, and a planetary gear 172 having the configuration of the gear 1 is inserted through the planetary shaft portion 173c. The carrier cover 1734 is disposed adjacent to the housing cover 150 in the axial direction inside the housing 140, and is slidable with respect to the housing cover 150.

[0045] The first carrier 173 is configured by assembling the carrier body 1732 and the carrier cover 1734 having the planetary shaft portion 173c, and thus the assembly efficiency of the first carrier 173 is improved. On the other hand, assembling a plurality of parts to form the first carrier 173 increases the tolerance, which may increase noise and reduce gear efficiency. However, since the planetary gear 172 has the first enlarged diameter portion 5 and the second enlarged diameter portion 6, the planetary gear 172 contacts the planetary shaft portion 173c at each of the first enlarged diameter portion 5 and the second enlarged diameter portion 6, and is supported rotatably about the planetary shaft portion 173c via these contact portions. This improves the meshing of the teeth and reduces noise.

[0046] The planetary shaft portion 173c of the carrier cover 1734 may be set to a diameter smaller than the hole into which the planetary shaft portion of the carrier body 1732 is inserted. By making the diameter of the planetary shaft portion 173c smaller than the diameter of the hole into which the planetary shaft portion of the carrier body 1732 is inserted, it is possible to suppress cracking of the carrier body due to the press-fitting of the planetary shaft portion 173c. On the other hand, it is considered that the planetary shaft portion 173c may be inclined due to the small diameter of the planetary shaft portion 173c. Even in this case, the planetary gear 172 contacts the planetary shaft portion 173c at each of the first enlarged diameter portion 5 and the second enlarged diameter portion 6, and is supported rotatably around the planetary shaft portion 173c through these contact portions. Therefore, the planetary gear 172 can mesh with other gears arranged adjacent to and connected to other gears without applying a load to the other gears.

[0047] The first internal gear 174 is a cylindrical body arranged around the planetary gear 172, and meshes with the planetary gear 172 at a first internal tooth portion 174a provided on the inner circumferential surface. The first internal tooth portion 174a has helical teeth cut obliquely with respect to the central axis of the first internal gear 174 (the central axis shared with the central axis of the motor rotating shaft 110). The first internal gear 174 is a helical gear.

[0048] A plurality of first ridges 174c (in this embodiment, three at each end spaced apart in the axial direction) having outer circumferential grooves 174b are provided on the outer circumferential surface of the first internal gear 174. The outer circumferential grooves 174b engage with ridges (not shown) formed on the inner circumferential surface of the main body tube portion 145, thereby restricting the rotation of the first internal gear 174 relative to the housing 140.

[0049] The second planetary gear mechanism 180 reduces the rotation transmitted from the first planetary gear mechanism 170 at a predetermined reduction ratio and outputs the reduced rotation. The second planetary gear mechanism 180 is provided on the other side in the axial direction (the right side in FIG. 4, the output side) of the first planetary gear mechanism 170.

[0050] The second planetary gear mechanism 180 is accommodated in the accommodation space of the housing 140 on the other axial side of the main body cylindrical portion 145 of the housing 140. Specifically, the second planetary gear mechanism 180 is disposed in a portion corresponding to the second internal gear portion (not shown) of the main body cylindrical portion 145. The second planetary gear mechanism 180 may be omitted.

[0051] The second planetary gear mechanism 180 includes a sun gear 181, a planetary gear 182, and a second carrier 183 that rotatably supports the planetary gear 182. The planetary gear 182 may be the gear 1 of the present embodiment.

[0052] The sun gear 181 is an external gear having a sun teeth portion on its outer circumferential surface. The sun teeth portion has helical teeth cut obliquely with respect to the central axis of the sun gear 181. The sun gear 181 is fixed to the first carrier 173 with their axes aligned. As a result, the sun gear 181 rotates in the same rotational direction as the first carrier 173 and at the same rotational speed as the first carrier 173 in conjunction with the rotation of the first carrier 173.

[0053] The planetary gear 182 is an external gear with planetary teeth formed on its outer circumferential surface. The multiple planetary gears 182 are arranged at equal intervals between the sun gear 181 and the second internal gear portion inside the main body tube portion 145, and mesh with both the sun gear 181 and the second internal gear portion. The multiple planetary gears 182 are arranged on the same circle centered on the axis of the second planetary gear mechanism 180, and are rotatably supported by the planetary shaft 186 of the second carrier 183. The planetary teeth portion of the planetary gear 182 has helical teeth that are cut obliquely with respect to the axis of the planetary gear 182. The planetary gear 182 is a so-called helical gear.

[0054] Each of the planetary gears 182 rotates about its own central axis (planetary axis 186) based on the rotation of the sun gear 181. Also, each of the planetary gears 182 revolves around the sun gear 181 based on its own rotation and meshing with the second internal gear portion. The central axis of revolution of the planetary gears 182 may coincide with the central axis of the sun gear 181.

[0055] The second carrier 183 rotatably supports the planetary gears 182 (rotatably). In addition, the second carrier 183 rotates based on the revolution of the planetary gears 182, and transmits the rotation to an output shaft connected to an output shaft connecting portion 187. The second carrier 183 has a gear holding portion 1834 and a second carrier body 1835 that holds the output shaft connecting portion 187.

[0056] The gear holder 1834 has a planetary shaft 186 provided in the axial direction on a ring portion disposed on the outer periphery of the sun gear 181. The planetary gears 182 are inserted into the planetary shaft 186, which supports the planetary gears 182 rotatably. The gear holder 1834 is joined to a second carrier body 1835. Each of the planetary gears 182 is exposed from an accommodation opening 183a formed on the outer periphery of the second carrier body 1835. The planetary teeth of the planetary gears 182 mesh with the teeth of the second internal gear portion through the accommodation opening 183a. The planetary shaft 185 may be formed integrally with the gear holder 1834 .

[0057] By configuring second carrier 183 by assembling second carrier body 1835 and gear holder 1834 having planetary shaft 185, it is possible to obtain the same effects as first carrier 173 described above.

[0058] Furthermore, the planetary shaft 185 of the gear holding portion 1834 may be set to have a smaller diameter than the hole into which the planetary shaft of the second carrier body 1835 is inserted. By making the diameter of the planetary shaft 185 smaller than the diameter of the hole into which the planetary shaft of the second carrier body 1835 is inserted, it is possible to obtain the same effect as that of the first carrier 173 described above.

[0059] The output shaft connecting portion 187 protrudes toward the other side (output side) beyond the second carrier body 1835, and is formed in a cylindrical shape with a smaller diameter than the second carrier body 1835. A knurled tooth is provided on the radially inner side of the output shaft connecting portion 187, and an output shaft is connected thereto.

[0060] FIG. 5 is a partial cross-sectional view of a main portion of the planetary gear device 100, showing a meshing state of the planetary gears when a misalignment occurs between the axis of the sun gear and the output shaft of the planetary gear device.

[0061] In the planetary gear set 100, for example, it is assumed that the rotating shaft 110 fixed to the sun gear 171 and the axis of the output shaft portion of the planetary gear set 100 (corresponding to the planetary shaft 186 provided on the carrier cover 1734 of the first carrier 173 in FIG. 5) are misaligned. In this case, when the sun gear 171 is coupled to the rotating shaft 110, the axis of the sun gear 171 itself also misaligns following the misalignment of the rotating shaft 110, and the planetary gear 172 meshing with the sun gear 171 also follows, causing the axis of the planetary gear 172 (shown as the axis of the insertion hole 3 in FIG. 5) to misalign.

[0062] 5, even if an external load is applied, the planetary gear 172 (corresponding to the gear 1) can tilt with respect to the planetary shaft portion 173c (corresponding to the shaft 11) inserted into the insertion hole 3. Also, the planetary gear 172 can rotate around the shaft 11 while making surface contact, line contact or point contact at a plurality of points (first enlarged diameter portion 5, second enlarged diameter portion 6) spaced apart in the axial direction.

[0063] Therefore, the planetary gear 172 can maintain a state of meshing with the sun gear 171 and the first internal tooth portion 174a of the first internal gear 174 while tilting with respect to the planetary shaft portion 173c due to the load. In other words, the same effect as a structure with crowning on the tooth surface can be obtained.

[0064] According to the gear 1 of this embodiment, the tooth surface can be provided with the same effect as that obtained by crowning the tooth surface without crowning the tooth surface, and therefore a die for crowning is not required, thereby reducing manufacturing costs. Also, the insertion hole 3 has an inner diameter that allows the shaft 11 to tilt inside the insertion hole 3, and the gear 1 can be rotatably supported on the shaft 11 via multiple points of surface contact or line contact.

[0065] <Variation 1> FIG. 6 is an external perspective view of gears in a modified example of the gear device according to one embodiment of the present invention, and FIG. 7 is a cross-sectional view showing a schematic diagram of the modified example of the same gear device.

[0066] 6 and 7, a gear device 10A having gear 1A is configured similarly to gear device 10 having gear 1 except that it has multiple gear bodies 2A, 2B. Therefore, for gear 1A, components common to the configuration of gear 1 are given the same reference numerals with A suffixed, and descriptions thereof will be omitted as appropriate.

[0067] The gear device 10A has a shaft 11A and a pair of gears (a first gear 20a and a second gear 20b) that constitute a gear main body 2A having an insertion hole 3A through which the shaft 11A is inserted.

[0068] The insertion hole 3A in the gear body 2A has enlarged diameter portions (first enlarged diameter portion 5A, second enlarged diameter portion 6A) that enlarge radially from positions 51A, 61A away from both end faces 2a, 2b toward each of the end faces 2a, 2b in the axial direction.

[0069] The first gear 20a has a first insertion hole 30a which constitutes the insertion hole 3A, and the first insertion hole 30a has a first enlarged diameter portion 5A.

[0070] The first enlarged diameter portion 5A radially enlarges from a position 51A away from one end face 2a of the first gear 20a toward the one end face 2a. The first enlarged diameter portion 5A has a first small diameter portion 50a with a relatively small diameter and a first large diameter portion 50b with a relatively large diameter at different positions in the axial direction. The first large diameter portion 50b has a larger diameter than the first small diameter portion 50a.

[0071] In the first gear 20a, when the shaft 11A is inclined relative to the first insertion hole 30a, the shaft 11A contacts the first small diameter portion 50a and enters into a space radially outward of the first small diameter portion 50a corresponding to the first large diameter portion 50b in the first large diameter portion 50b.

[0072] On the other hand, the second gear 20b has a second insertion hole 30b which constitutes the insertion hole 3A, and the second insertion hole 30b has a second enlarged diameter portion 6A.

[0073] The second enlarged diameter portion 6A radially enlarges from a position 61A away from one end face 2b of the second gear 20b toward the one end face 2b. The second enlarged diameter portion 6A has a second small diameter portion 60a with a relatively small diameter and a second large diameter portion 60b with a relatively large diameter at different positions in the axial direction. The second large diameter portion 60b has a larger diameter than the second small diameter portion 60a.

[0074] The first gear 20a and the second gear 20b are arranged such that the first enlarged diameter portion 5A and the second enlarged diameter portion 6A face in directions away from each other. The first gear 20a and the second gear 20b are formed, for example, in the same shape. The first gear 20a and the second gear 20b may be molded by injection molding.

[0075] In the second gear 20b, when the shaft 11A is inclined relative to the second enlarged diameter portion 6A, the shaft 11A contacts the second small diameter portion 60a and enters a space radially outward of the second small diameter portion 60a corresponding to the second large diameter portion 60b in the second large diameter portion 60b.

[0076] The first enlarged diameter portion 5A and the second enlarged diameter portion 6A each have a tapered surface, and the tapered surface may be linear or curved in cross section.

[0077] In variant example 1, in a gear 1A having an insertion hole 3A through which an axis 11A is inserted and which penetrates in the axial direction, the insertion hole 3A has a first expanded diameter portion 5A and a second expanded diameter portion 6A which radially expand in diameter from positions 51A, 61A away from both end faces 2a, 2b in the axial direction toward both end faces 2a, 2b.

[0078] In this way, the gear 1A having an insertion hole 3A whose diameter expands toward both sides in the axial direction due to the first enlarged diameter portion 5A and the second enlarged diameter portion 6A is composed of a pair of gears, the first gear 20a and the second gear 20b.

[0079] In the first gear 20a and the second gear 20b, the first insertion hole 30a and the second insertion hole 30b are each formed to expand in one axial direction, so that the first gear 20a and the second gear 20b can be injection molded using a simple mold that is simply punched in one axial direction, which is the opening direction of the first insertion hole 30a and the second insertion hole 30b.

[0080] As a result, according to the gear device 10A having the gear 1A of the first modification, when a gear having the above-mentioned effects is molded by injection molding, secondary processing for removing the axial ends is not required, making the manufacturing process easier. In addition, since there is no need to use a complicated mold that uses a separate core for secondary processing, the manufacturing cost can be reduced.

[0081] Furthermore, since the first gear 20a and the second gear 20b have the same shape, it is possible to mold the gear 1A using a single mold without preparing separate molds for manufacturing the first gear 20a and the second gear 20b, thereby reducing production costs.

[0082] In the gears 1, 1A, the through holes 3, 3A formed through the gear bodies 2, 2A and through which the shafts 11, 11A are inserted have a central portion having a cylindrical inner peripheral surface along the axial direction at the center of the gear bodies 2, 2A. The axial ends of this central portion are, for example, positions 51, 51A, 61, 61A away from the end ends 2a, 3b. From these positions 51, 51A, 61, 61A, the first enlarged diameter portions 5, 5A and the second enlarged diameter portions 6, 6A are provided, which are enlarged in diameter at a predetermined taper (including a curved linear surface shape) toward the end faces 2a, 2b, respectively. The tapers of the first enlarged diameter portions 5, 5A and the second enlarged diameter portions 6, 6A formed on either side of these central portions are preferably shaped to make surface contact, line contact in the axial direction, etc. when the shafts 11, 11A inserted through the through holes 3, 3A are inclined. The first enlarged diameter portion 5, 5A and the second enlarged diameter portion 6, 6A have, for example, a space having a truncated cone shape.

[0083] This allows the gears 1, 1A to be rotatably supported on the shafts 11, 11A even if the shafts 11, 11A are inclined relative to the insertion holes 3, 3A (in other words, the gears 1, 1A), or even if the insertion holes 3, 3A are inclined relative to the shafts 11, 11A.

[0084] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0085] The above describes the embodiment of the present invention. Note that the above description is an example of a preferred embodiment of the present invention, and the scope of the present invention is not limited thereto. In other words, the above description of the gears and gear device configurations and the shapes of each part are examples, and it is clear that various modifications and additions to these examples are possible within the scope of the present invention. [Industrial Applicability]

[0086] INDUSTRIAL APPLICABILITY The gear, gear device, and planetary gear device according to the present invention have the effect of being low cost and capable of smoothly meshing with other gears, and are useful for use in various mechanical devices such as automobiles and robots. [Explanation of symbols]

[0087] 1. 1A Gear 2, 2A, 2B Gear body 2a, 2b One end surface 3, 3A Insertion hole 4 Expanded diameter part 5, 5A 1st enlarged diameter section 5a, 6a Small diameter section 5b, 6b Large diameter section 6, 6A 2nd enlarged diameter section 10, 10A Gearing 11, 11A axis 20a 1st Gear 20b 2nd Gear 22 Teeth 24 Cylindrical protrusion 30a First insertion hole 30b Second insertion hole 50a First small diameter section 50b First large diameter section 51, 51A, 61, 61A positions 60a Second small diameter section 60b Second large diameter section 100 Planetary Gear Unit 110 Rotational axis 130 Gear mechanism 140 Housing 145 Main body cylinder 146 Circular limbus 147 Support cylinder part 150 housing cover 151 Central opening 170 First planetary gear mechanism 171, 181 Sun gear 172, 182 Planetary gear 173 First Career 173a Storage opening 173b Circular body 173c Planetary shaft 174 First internal gear 174a First inner teeth 174b Outer circumferential groove 174c 1st protrusion 180 Second planetary gear mechanism 183 Second Career 183a Storage opening 186 Planetary shaft 187 Output shaft connection 1732 Carrier body 1734 Carrier Cover 1834 Gear holder 1835 2nd Carrier Body

Claims

1. a gear body having an insertion hole for inserting a shaft formed therethrough in the axial direction; the insertion hole has a first enlarged diameter portion and a second enlarged diameter portion that radially enlarge from respective positions away from both end faces in the axial direction toward the both end faces, When the shaft is inclined with respect to the insertion hole, each of the first enlarged diameter portion and the second enlarged diameter portion comes into surface contact or line contact with the shaft. gear.

2. A gear device having the gear according to claim 1, The shaft; the gear body having the shaft inserted through the insertion hole; having the first enlarged diameter portion and the second enlarged diameter portion each have a small diameter portion having a relatively small diameter and a large diameter portion having a relatively large diameter at different positions in the axial direction, and when the shaft is inclined with respect to the insertion hole, the shaft comes into contact with the small diameter portion and enters a space radially outward of the small diameter portion at the large diameter portion; Gear mechanism.

3. A gear body having an insertion hole for inserting a shaft penetrating therethrough in the axial direction, the insertion hole having a pair of gears having an enlarged diameter portion which expands radially from a position away from one end face in the axial direction toward the one end face, The shaft; a first gear of the pair of gears, the shaft of which is inserted through the insertion hole; a second gear of the pair of gears, the shaft of which is inserted through the insertion hole; having the first gear and the second gear are disposed such that the enlarged diameter portions face in directions away from each other and radially enlarge toward the one end faces of the first gear and the second gear that are separated from each other, the enlarged diameter portion of the first gear and the enlarged diameter portion of the second gear each have a small diameter portion having a relatively small diameter and a large diameter portion having a relatively large diameter, at different positions in the axial direction, When the shaft is inclined with respect to the insertion hole, the enlarged diameter portion of the first gear and the enlarged diameter portion of the second gear come into surface contact or line contact with the shaft, and the shaft comes into contact with each of the small diameter portions, and at each of the large diameter portions, the shaft enters a space radially outward of each of the small diameter portions corresponding to each of the large diameter portions. Gear mechanism.

4. The gear device according to claim 2 or 3, The gear is a planetary gear that is disposed between the sun gear and the internal gear and meshes with both of them, The shaft is a planetary shaft portion provided on a carrier that supports the planetary gear so as to be able to revolve around the sun gear and rotates based on the revolution of the planetary gear. Planetary gear set.

5. The carrier and the planetary shaft portion are integrally formed.

5. The planetary gear device according to claim 4.

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