Planetary gear device

Abstract

A planetary gear device (1) is provided with a sun gear (5), a carrier (6), and a plurality of planetary units (7) and a ring gear (9) provided on the carrier (6). Each planetary unit (7) is provided with: a first planetary gear (71) that meshes with the sun gear (5); a second planetary gear (72) that meshes with the ring gear (9); a first rotating body (73) disposed coaxially with the first planetary gear (71); a second rotating body (74) disposed coaxially with the second planetary gear (72); and a winding transmission body (75) wound around the first rotating body (73) and the second rotating body (74). The winding transmission bodies (75) of the plurality of planetary units (7) are arranged so that at least parts of the winding transmission bodies (75) overlap each other in the axial direction when viewed from a direction orthogonal to the axial direction.

Description

Technical Field

[0001] The present invention relates to a planetary gear arrangement. Background Art

[0002] In the past, a planetary transmission has been proposed, which includes a housing, two sun gears, a planet carrier, two planetary gears, a meshed wheel, and two toothed belts. The two planetary gears are respectively formed by integrating a small diameter gear and a large diameter sprocket, and the large diameter sprockets of these planetary gears are respectively meshed with the meshed wheel.

[0003] In addition, one of the two toothed belts is wound around the sun gear of one of the two sun gears and the small diameter gear of one of the two planetary gears, and the other of the two toothed belts is wound around the sun gear of the other of the two planetary gears and the small diameter gear of the other of the two planetary gears.

[0004] Patent Document 1: Japanese Utility Model Application Laid-Open No. 6-69494

[0005] The planetary transmission of the above-mentioned patent document 1 is configured such that, among the three elements of the sun gear, the planet carrier, and the meshed gear, for example, the meshed gear is fixed and the sun gear is used as input, thereby being able to function as a speed reducer that outputs a reduced speed rotation from the planet carrier. Alternatively, the meshed gear is fixed and the planet carrier is used as input, thereby being able to function as a speed increaser that outputs a increased speed rotation from the sun gear.

[0006] However, the planetary transmission of Patent Document 1 has a problem that the axial length of the planetary transmission becomes longer because the two toothed belts are offset in the direction of the rotation axis. In particular, in the case of this structure, the more the number of planetary gears and toothed belts, the longer the axial length of the planetary transmission. Summary of the invention

[0007] The present invention provides a planetary gear device which is compact in the axial direction.

[0008] One embodiment of the present invention is a planetary gear device, characterized in that it comprises: a sun gear, a planetary carrier, a plurality of planetary units arranged on the above-mentioned planetary carrier, and a ring gear, the above-mentioned planetary units respectively comprise: a first planetary gear, which is meshed with the above-mentioned sun gear and is rotatably supported on the above-mentioned planetary carrier; a second planetary gear, which is meshed with the above-mentioned ring gear and is rotatably supported on the above-mentioned planetary carrier; a first rotating body, which is coaxially arranged with the above-mentioned first planetary gear; a second rotating body, which is coaxially arranged with the above-mentioned second planetary gear; and a winding transmission body, which is wound around the above-mentioned first rotating body and the second rotating body, and each winding transmission body of the above-mentioned plurality of planetary units is configured so that when viewed from a direction orthogonal to the axial direction, at least a portion of them overlap with each other in the above-mentioned axial direction.

[0009] A planetary gear device that is compact in the axial direction can be provided.

[0010] Other features and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings. In addition, in the accompanying drawings, the same reference numerals are used to designate the same or similar structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a front view showing the planetary gear device of the present embodiment with the planetary carrier removed.

[0012] Figure 2 yes Figure 1 A II-II sectional view of the planetary gear device is shown.

[0013] Figure 3A It is a side view showing a planetary gear device of a comparative example.

[0014] Figure 3B It is a side view showing the planetary gear device according to the present embodiment.

[0015] Figure 4 This is a diagram for explaining the tension adjustment mechanism of the planetary chain 75 .

[0016] Figure 5 It is a front view of a planetary gear device according to a modified example, showing a state in which the planetary carrier is removed. DETAILED DESCRIPTION

[0017] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0018] (Brief structure of chain-type planetary sprocket reducer)

[0019] Figure 1 The planetary gear device of this embodiment is a chain-type planetary sprocket reducer 1. Figure 2 As shown, the chain-type planetary sprocket reducer 1 is arranged between an input shaft 2 as a first shaft for transmitting input rotation from a driving source not shown in the figure and an output shaft 3 as a second shaft whose axis is consistent with the input shaft 2, and reduces the input rotation input to the input shaft 2 from the output shaft 3 and outputs it.

[0020] Specifically, the speed reducer 1 is configured to include: a sun gear 5 provided on the input shaft 2, a planetary carrier 6, a plurality of (three in this embodiment) planetary units 7 provided on the planetary carrier 6, and a ring gear (internal gear) 9 provided on the output shaft 3. When the input shaft 2 is driven to rotate by a driving force from a driving source such as a motor of a motorcycle, the sun gear 5 rotates integrally with the input shaft 2.

[0021] The planetary carrier 6 is composed of a pair of circular flat plates 61 and 62 connected by bushing bolts 63 as fasteners at a predetermined interval in the axial direction, and a plurality of planetary units 7 are arranged between the flat plates 61 and 62. In the present embodiment, the planetary carrier 6 is fixed to a fixing member (not shown).

[0022] The plurality of planetary units 7 each include a first planetary gear 71 meshing with the sun gear 5 , a second planetary gear 72 meshing with the ring gear 9 , a first planetary sprocket 73 , a second planetary sprocket 74 , and a planetary chain 75 wound around the first planetary sprocket 73 and the second planetary sprocket 74 .

[0023] The first planetary gear 71 is rotatably supported on the planetary carrier 6 via the first planetary shaft 76. In addition, the first planetary sprocket 73 is provided on the first planetary shaft 76, and the first planetary sprocket 73 and the first planetary gear 71 are configured to rotate integrally. More specifically, the first planetary sprocket 73 is supported to be rotatable relative to the first planetary shaft 76, and the first planetary gear 71 is fixed to the hub portion 73a of the first planetary sprocket 73 extending in the axial direction of the first planetary shaft 76.

[0024] The second planetary gear 72 is formed to have a larger number of teeth and a larger diameter than the first planetary gear 71, and is rotatably supported by the planetary carrier 6 via the second planetary shaft 77. In addition, the second planetary shaft 77 is provided with a second planetary sprocket 74 having a larger diameter than the first planetary sprocket 73, and the second planetary sprocket 74 and the second planetary gear 72 are configured to rotate integrally.

[0025] More specifically, the second planetary sprocket 74 and the second planetary gear 72 are supported to rotate freely relative to the second planetary shaft 77, and the second planetary sprocket 74 and the second planetary gear 72 are connected by bolts 78 as fastening members to rotate integrally. In addition, the first planetary sprocket 73 and the second planetary sprocket 74 are driven and connected by the planetary chain 75, thereby driving and connecting the first planetary gear 71 and the second planetary gear 72. In addition, a tension roller (not shown) is arranged between the first planetary sprocket 73 and the second planetary sprocket 74, and an appropriate tension is applied to the planetary chain 75 in a manner that does not cause tooth jump.

[0026] The ring gear 9 is formed in a drum-like shape and has a bottom 91 extending in the radial direction and a flange 92 extending in the axial direction from the outer peripheral edge of the bottom 91. The bottom 91 is fixed to the flange 3a of the output shaft 3 by a fastener 93 such as a bolt. The flange 92 is formed separately from the bottom 91 and is fixed to the bottom 91 by a fastener 95 such as a bolt. In addition, a tooth surface that meshes with the second planetary gear 72 is formed on the inner peripheral surface of the flange 92. The ring gear 9 has a larger number of teeth and a larger diameter than the sun gear 5 and the first and second planetary gears 71 and 72.

[0027] Since the structure is constructed as described above, if the input rotation is input to the input shaft 2, the sun gear 5 rotates. If the sun gear 5 rotates, the power is transmitted to each of the three planetary units 7 via the first planetary gear 71 meshing with the sun gear 5. For the three planetary units 7, since the planet carrier 6 is fixed, if the rotation is input from the sun gear 5, each rotating body 71, 72, 73, 74 rotates without revolving. More specifically, the second planetary sprocket 74 is a sprocket with a larger number of teeth than the first planetary sprocket 73, so the rotation input from the sun gear 5 is decelerated and transmitted to the ring gear 9 through the second planetary gear 72. The ring gear 9 rotates through the second planetary gear 72, and thus, the rotation that is decelerated compared to the rotation speed of the input shaft 2 is output from the output shaft 3 that is integral with the ring gear 9.

[0028] (Axial length of chain-type planetary sprocket reducer)

[0029] Next, the axial length of the chain type planetary sprocket reducer 1 is described. As described above, in this embodiment, the planetary unit 7 is configured such that the planetary chain 75 is not directly wound around the sun gear 5, but the first planetary gear 71 is provided as an intermediate gear so that the first planetary gear 71 meshes with the sun gear 5.

[0030] Therefore, even if the speed reducer 1 of the present embodiment includes a plurality of planetary units 7 , the axial positions of the first planetary sprocket 73 , the second planetary sprocket 74 , and the planetary chain 75 of each planetary unit 7 can be made consistent by changing the phases of the planetary units 7 .

[0031] When a plurality of planetary chains 75 are directly wound around the sun gear 51, it is necessary to arrange the chains 75 in an axially offset manner without interfering with each other. Figure 3A When three planetary units are arranged as in the comparative example shown, a width L3 of at least three chains is required.

[0032] On the other hand, in this embodiment, if Figure 3B As shown, the planetary chain 75 is arranged in such a way that the axial positions overlap, so that, for example, even when three planetary units 7 are arranged, they can be arranged with a width L1 of one chain. Therefore, even if the allowable torque is the same in the reducer of the comparative example and the reducer 1 of the present embodiment, the reducer 1 of the present embodiment can be compactly configured in the axial length.

[0033] In addition, if Figure 2As shown, the gear train of the sun gear 5 and the first planetary gear 71, the ring gear 9, and the second planetary gear 72 is located radially inside the tooth surface of the ring gear 9, while the drive train of the first planetary sprocket 73, the second planetary sprocket 74, and the planetary chain 75 is axially offset and arranged on the input shaft side relative to the ring gear 9. Therefore, the tooth top position of the second planetary sprocket 74 is located radially outside the tooth top of the ring gear 9, and the planetary sprockets 73 and 74 with larger diameters can be used. Therefore, the degree of freedom in design is large, and the speed ratio can be designed in a wide range.

[0034] (Tension adjustment mechanism)

[0035] Next, the tension adjustment mechanism of the planetary chain 75 will be described. In the tension adjustment mechanism of the present embodiment, the second planetary sprocket 74 can be mounted at a plurality of different phases, thereby configuring the tension adjustment mechanism of the planetary chain 75.

[0036] Specifically, if Figure 4 As shown, six mounting holes 741 to 743 for bolts 78 for fixing the second planetary sprocket 74 to the second planetary gear 72 are formed on the side surface of the second planetary sprocket 74. These mounting holes 741 to 743 are grouped into two mounting holes located on a diagonal line, so that the second planetary sprocket 74 can be mounted at three different phases with different degrees of meshing between the planetary chain 75 and the second planetary sprocket 74.

[0037] Right now, Figure 4 The angles A, B, and C in the figure are in different phases, and the second planetary sprocket 74 can be fixed at the first mounting position fixed by the first mounting hole 741, the second mounting position fixed by the second mounting hole 742, and the third mounting position fixed by the third mounting hole 743. It can be seen that the positions where the imaginary lines 741L to 743L obtained by connecting the centers of the mounting holes 741 to 743 intersect with the tooth surfaces between the adjacent tooth tops are different in phase with each other in the rotation direction of the second planetary sprocket 74 at the above-mentioned first to third mounting positions, and the first to third mounting positions are positions with different degrees of progress in the degree of meshing between the planetary chain 75 and the second planetary sprocket 74.

[0038] As described above, the chain changes its distance from the center of the sprocket according to the degree of engagement with the sprocket. Therefore, by changing the fixed position of the second planetary sprocket 74 between these first to third installation positions, the relative phase of the second planetary sprocket 74 with respect to the first planetary sprocket 73 can be changed, and the tension of the planetary chain 75 can be adjusted.

[0039] As such, in this embodiment, the plurality of mounting holes 741 to 743 and the bolt 78 constitute a tension adjustment mechanism. Figure 4As shown, the second planetary sprocket 74 can be fixed at a plurality of phase positions with different degrees of chain meshing relative to the first planetary sprocket 73 at the first phase position. Furthermore, by changing the relative rotational phase relationship (rotational position relationship) between the first planetary sprocket 73 and the second planetary sprocket 74, the tension of the planetary chain 75 can be adjusted.

[0040] Summary

[0041] The planetary gear device (1) of this embodiment includes:

[0042] Sun gear (5);

[0043] Planet carrier (6);

[0044] A plurality of planetary units (7) arranged on the planetary carrier (6); and

[0045] Ring gear (9),

[0046] The planetary units (7) are respectively equipped with:

[0047] a first planetary gear (71) meshing with the sun gear (5) and rotatably supported by the planetary carrier (6);

[0048] a second planetary gear (72) meshing with the ring gear (9) and rotatably supported by the planetary carrier (6);

[0049] A first rotating body (73) which is coaxially arranged with the first planetary gear (71);

[0050] a second rotating body (74) disposed coaxially with the second planetary gear (72); and

[0051] A winding transmission body (75) is wound around the first rotating body (73) and the second rotating body (74).

[0052] The winding transmission bodies (75) of the plurality of planetary units (7) are arranged so that, when viewed from a direction perpendicular to the axial direction, at least a portion of them overlap each other in the axial direction.

[0053] In this way, by arranging the winding transmission bodies 75 of the plurality of planetary units 7 so that at least a portion overlaps each other in the axial direction when viewed from a direction orthogonal to the axial direction, the planetary gear device 1 can be compactly configured in the axial direction. In particular, in the case of a motorcycle using a high-rotation, low-torque motor as a drive source, the axial length of the motor becomes long, so it is required to shorten the axial length of the transmission. By using the planetary gear device 1 of the embodiment of the present application, a transmission that is compact in the axial direction can be configured. In addition, the drive source is not limited to a motor, and may be, for example, an engine, etc. In addition, it is not limited to a motorcycle, and the planetary gear device 1 of the embodiment of the present application can be used for transmissions of bicycles, automobiles, etc.

[0054] In addition, the planetary gear device 1 of this embodiment can easily adjust the backlash by using the winding transmission body 75 compared with the conventional gear-type planetary gear mechanism, and can reduce the design and assembly cost. In addition, the allowable torque can be easily changed by changing the size and number of the winding transmission body 75. In addition, the number of planetary units 7 can be changed without changing the axial length of the planetary gear device 1, so the allowable input value can be increased while the planetary gear device 1 is kept compact.

[0055] In addition, in the above-mentioned embodiment, an example of using the planetary gear device 1 as a speed reducer by fixing the planetary carrier 6 is described, but it is not limited to this. The planetary gear device 1 can not only reduce speed, but also generate speed-up rotation and reverse rotation by changing the input, output, and fixation between the three elements of the sun gear 5, the planetary carrier 6, and the ring gear 9. For example, by setting the planetary carrier to be fixed, the ring gear to be input, and the sun gear to be output, it can function as a speed increaser.

[0056] In the above-mentioned embodiment, the planetary chain 75 is exemplified as the winding transmission body, the first planetary sprocket 73 is exemplified as the first rotating body, and the second planetary sprocket 74 is exemplified as the second rotating body. However, the planetary chain 75 may be other types of chains instead of roller chains. For example, Figure 5 As shown, the planetary chain can also be composed of a silent chain 751. In addition, the winding transmission body does not necessarily have to be a chain, and can also be, for example, a toothed belt, a flat belt, a V-belt, etc. In addition, the first rotating body and the second rotating body can also be composed of pulleys, etc.

[0057] In addition, the first planetary gear 71 and the first planetary sprocket 73 may be provided integrally, and the second planetary gear 72 and the second planetary sprocket 74 may be provided integrally. In addition, the first planetary gear 71, the first planetary sprocket 73, the second planetary gear 72, and the second planetary sprocket 74 may be of any size, and for example, the number of teeth of the first planetary sprocket 73 and the second planetary sprocket 74 may be the same. In addition, in the above-mentioned embodiment, the relative rotational phase relationship (rotational position relationship) between the first planetary sprocket 73 and the second planetary sprocket 74 is configured to be able to be installed in multiple positions, but it is also possible to configure the first planetary sprocket 73 to be able to be installed in multiple positions. In addition, as long as the relative rotational phase relationship (rotational position relationship) between the first planetary sprocket 73 and the second planetary sprocket 74 can be changed, it is not necessary to fix the position of the sprocket by bolts and mounting holes, and for example, the position of the sprocket may be fixed by concave and convex fitting.

[0058] Industrial Applicability

[0059] The present invention can be widely implemented in the field of planetary gear devices.

[0060] The present invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, in order to disclose the scope of the present invention, the following claims are attached.

[0061] Description of Reference Numerals

[0062] 1…planetary gear device (chain-type planetary sprocket reducer); 5…sun gear; 6…planet carrier; 7…planetary unit; 9…ring gear; 71…first planetary gear; 72…second planetary gear; 73…first rotating body (first planetary sprocket); 74…second rotating body (second planetary sprocket); 75…winding transmission body (planetary chain).

Claims

1. A planetary gear device, characterized in that: have: Sun gear; Planet carrier; A plurality of planetary units disposed on the planet carrier; and Ring gear, The planetary units respectively include: a first planetary gear meshing with the sun gear and rotatably supported by the planet carrier; a second planetary gear meshing with the ring gear and rotatably supported by the planet carrier; a first rotating body, wherein the first rotating body and the first planetary gear are arranged on the same axis; a second rotating body, wherein the second rotating body and the second planetary gear are arranged on the same axis; as well as a winding transmission body, wherein the winding transmission body is wound around the first rotating body and the second rotating body, The winding transmission bodies of the plurality of planetary units are arranged so that at least a portion of them overlap with each other in the axial direction when viewed from a direction perpendicular to the axial direction.

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