Speed reduction mechanism and drive device

Abstract

A reduction mechanism and a driving device are provided. The reduction mechanism of an embodiment of the present application includes: a two-stage planetary gear mechanism; a first planetary gear carrier that restricts a second planetary gear of the second-stage planetary gear mechanism from falling out of a second support shaft portion; and a ring-shaped second thrust plate that is provided between the first planetary gear carrier and the second planetary gear, into which the second support shaft portion is inserted. The thickness of the second thrust plate is greater than the gap between the tip surface of the second support shaft portion and the first planetary gear carrier.

Description

Technical Field

[0001] This invention relates to a speed reduction mechanism and a drive device. Background Technology

[0002] Generally, multi-stage planetary gear mechanisms are used as speed reduction mechanisms. Each stage of a multi-stage planetary gear mechanism includes: a sun gear, which is integrally mounted with the input-side rotating shaft; planet gears, which mesh with the sun gear; and a planetary gear carrier, which supports the planet gears and allows them to rotate freely, and is integrally mounted with the output-side rotating shaft. The planet gears are rotatably supported on a support shaft provided on the planetary gear carrier.

[0003] Various techniques have been disclosed for preventing planetary gears of any stage from contacting planetary gear carriers of other stages adjacent to the planetary gear, thereby limiting the detachment of planetary gears relative to the support shaft. For example, a technique has been disclosed in which a thrust plate (thrust ring) is fixed to the end face of the support shaft by bolts, the thrust plate (thrust ring) being formed in a ring shape that extends across the support shaft and the end face of the planetary gear (see, for example, Patent Document 1).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 9-269036 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] However, in the aforementioned prior art, it is necessary to form an internal thread for bolt fastening in the support shaft or a hole for bolt penetration in the thrust plate, which may complicate the construction.

[0009] The present invention provides a speed reduction mechanism and drive device that can simplify the construction even when a thrust plate is provided to prevent unwanted contact between components.

[0010] Solution for solving the problem

[0011] (1) A speed reduction mechanism according to a technical solution of the present invention comprises: a planetary gear mechanism having: a sun gear; a planetary gear meshing with the sun gear; and a planetary gear carrier having a support shaft portion that supports the planetary gear for rotation; a limiting portion that limits the planetary gear from falling off the support shaft portion; and an annular thrust plate disposed between the planetary gear and the limiting portion and inserted into the support shaft portion, wherein the maximum thickness of the thickest part of the thrust plate is greater than the distance between the top surface of the support shaft portion on the side of the limiting portion and the limiting portion.

[0012] With this configuration, the thrust plate can be used to prevent the planetary gear from detaching from the support shaft without fixing it to the support shaft. Therefore, the structure of the reduction mechanism can be simplified.

[0013] The maximum thickness of the thrust plate is greater than the gap between the top surface of the support shaft on the side of the limiting part and the limiting part, thus preventing the planetary gear, the support shaft and the limiting part from direct contact.

[0014] (2) Alternatively, the planetary gear may have: an insertion hole for the support shaft portion to be inserted; and a recess formed on the inner circumference of the planetary gear on one end face near the limiting portion in a manner communicating with the insertion hole, the thrust plate being disposed in the recess, the recess having an inner surface that limits radial displacement of the thrust plate.

[0015] (3) Alternatively, the reduction mechanism may have a bearing that fits into the outer circumferential surface of the support shaft and into the inner circumferential surface of the insertion hole of the planetary gear, for supporting the planetary gear to rotate freely relative to the support shaft, and the thrust plate is disposed at a position in the axial direction of the support shaft where the thrust plate overlaps with the bearing around its entire circumference.

[0016] (4) Alternatively, the thrust plate may have a fluid passage formed in such a way that it passes through the axial direction of the support shaft, allowing fluid to pass through.

[0017] (5) Alternatively, the planetary gear mechanism may have a plurality of planetary gears and a support shaft, and each of the plurality of planetary gears may be provided with a thrust plate.

[0018] (6) Alternatively, a plurality of planetary gear mechanisms may be arranged along the axial direction of the support shaft, and the limiting part is the planetary gear carrier, which is arranged between the planetary gear of one planetary gear mechanism and the planetary gear of another planetary gear mechanism in the planetary gear mechanisms that are adjacent to each other in the axial direction.

[0019] (7) Another technical solution of the present invention provides a deceleration mechanism comprising: a plurality of planetary gear mechanisms; and a thrust plate disposed between two of the planetary gear mechanisms, wherein the planetary gear mechanism comprises: a sun gear; planetary gears meshing with the sun gear and revolving around the sun gear due to the rotation of the sun gear; a planetary gear carrier having a protruding support shaft portion supporting the planetary gears in a rotatable manner, the planetary gear carrier being rotatable about the central axis of the sun gear; and a bearing fitted into the outer peripheral surface of the support shaft portion for supporting the planetary gears rotatably on the support shaft portion, wherein a plurality of planetary gear mechanisms are arranged along the axial direction of the support shaft portion, and in In the axially adjacent planetary gear mechanisms, the planetary gears of one planetary gear mechanism and the planetary gear carriers of the other planetary gear mechanism are arranged adjacently. The thrust plate is formed as an annular shape that is inserted into the support shaft portion and is disposed between the planetary gears of one planetary gear mechanism and the planetary gear carriers of the other planetary gear mechanism. It is also disposed at a position where the thrust plate overlaps with the bearing around its entire circumference in the axial direction of the support shaft portion. The maximum thickness of the thrust plate at its thickest part is greater than the interval between the top surface of the support shaft portion of one planetary gear mechanism and the planetary gear carrier of the other planetary gear mechanism.

[0020] This configuration also allows the thrust plate to be used to prevent the planetary gear from detaching from the support shaft without fixing it to the support shaft. Therefore, the structure of the reduction mechanism can be simplified.

[0021] The maximum thickness of the thrust plate is greater than the distance between the top surface of the support shaft on the side of the limiting part and the limiting part, thus preventing the planetary gear from directly contacting the limiting part. In addition, the insertion hole and the recess are connected, and the thrust plate is positioned in the axial direction of the support shaft where the thrust plate overlaps with the bearing around its entire circumference, thus ensuring that lubricating oil is distributed evenly throughout the bearing, the insertion hole, and the recess without any leakage.

[0022] (8) Another driving device according to the present invention includes: a reduction mechanism; and a driving source that transmits driving force to the reduction mechanism, the reduction mechanism including: a planetary gear mechanism having: a sun gear; planetary gears that mesh with the sun gear and revolve around the sun gear due to the rotation of the sun gear; and a planetary gear carrier that is provided with a support shaft portion that supports the planetary gears to be rotatable, the planetary gear carrier being rotatable about the central axis of the sun gear; a limiting portion that limits the planetary gears from falling off the support shaft portion; and an annular thrust plate that is disposed between the planetary gears and the limiting portion and is inserted into the support shaft portion, the maximum thickness of the thickest part of the thrust plate being greater than the distance between the top surface of the support shaft portion on the limiting portion side and the limiting portion.

[0023] With this configuration, a drive unit whose construction is simplified can be provided even when a thrust plate is provided to prevent unwanted contact between parts.

[0024] The effects of the invention

[0025] The deceleration mechanism and drive device according to the present invention can simplify the construction even when a thrust plate is provided to prevent undesirable contact between components. Attached Figure Description

[0026] Figure 1 This is a cross-sectional view showing the motor with a speed reducer according to the first embodiment of the present invention, and is taken along the central axis.

[0027] Figure 2 yes Figure 1 Enlarged view of part A.

[0028] Figure 3 This is an enlarged view of the main part of the second-stage planetary gear mechanism in the second embodiment of the present invention.

[0029] Figure 4 This is an enlarged view of the main part of the second-stage planetary gear mechanism in the third embodiment of the present invention.

[0030] Figure 5 This is a top view obtained by viewing the second thrust plate in the fourth embodiment of the present invention from the direction of the central axis.

[0031] Figure 6 This is a top view obtained by viewing the second thrust plate in the fifth embodiment of the present invention from the direction of the central axis.

[0032] Explanation of reference numerals in the attached figures

[0033] 1. Motor with reducer (drive unit); 2. Motor (drive source); 3. Reduction mechanism; 24, 224, 424, 524, Second thrust plate (thrust plate); 25. Recess; 25b. Inner surface; 31A. First stage planetary gear mechanism; 31B. Second stage planetary gear mechanism; 35. First planetary gear carrier (restriction part); 43. Second sun gear (sun gear); 44, 244, 344. Second planetary gear (planetary gear); 44h. Insertion hole; 45. Second planetary gear carrier (planetary gear carrier); 46. Bearing; 47, 247. Second support shaft (support shaft part); 47a, 247a. Top surface; 428. Recess (fluid passage); 528. Hole (fluid passage); C. Central axis; G. Spacing. Detailed Implementation

[0034] Next, embodiments of the present invention will be described with reference to the accompanying drawings.

[0035] [First Implementation]

[0036] <Motor with speed reducer>

[0037] Figure 1 This is a cross-sectional view of a motor 1 with a speed reducer, which is used as a drive device, along the central axis C. Figure 2 yes Figure 1 Enlarged view of part A.

[0038] like Figure 1 , Figure 2 As shown, the motor 1 with a speed reducer includes a motor (an example of the drive source in the claims) 2 and a speed reduction mechanism 3 connected to the motor shaft 2a of the motor 2.

[0039] Motor 2 has a housing 7 for integration with reduction gear 3. Motor shaft 2a protrudes through housing 7 toward reduction gear 3. Motor 2 is connected to an external power source (not shown) from which power is supplied. Motor shaft 2a rotates using this power, and this rotation is transmitted to reduction gear 3. That is, motor 2 is the drive source that transmits driving force to reduction gear 3. The axis of motor shaft 2a coincides with the central axis C of motor 1 with reduction gear.

[0040] <Speed ​​Reduction Mechanism>

[0041] The reduction mechanism 3 includes a housing 30 and a multi-stage (two-stage in this embodiment) planetary gear mechanism 31A, 31B (first-stage planetary gear mechanism 31A and second-stage planetary gear mechanism 31B) disposed within the housing 30.

[0042] The housing 30 is integrally formed by a cylindrical portion 30a with the central axis C as the axial direction and a sealing plate portion 30b that seals the end of the cylindrical portion 30a opposite to the motor 2. The open end of the cylindrical portion 30a on the side facing the motor 2 is mated with the housing 7 of the motor 2 and fixed to the housing 7 by bolts (not shown).

[0043] A gear ring 40 is provided on the inner circumferential surface of the cylindrical portion 30a, on the motor 2 side. The gear ring 40 is formed into a cylindrical shape along the inner circumferential surface of the cylindrical portion 30a. Gear teeth 40g are formed on the inner circumferential surface of the gear ring 40. Two-stage planetary gear mechanisms 31A and 31B mesh with the gear teeth 40g. The two-stage planetary gear mechanisms 31A and 31B are arranged from the motor 2 side along the central axis C in the order of first-stage planetary gear mechanism 31A and second-stage planetary gear mechanism 31B.

[0044] A shaft through hole 30h is formed radially at the center of the sealing plate portion 30b. Two bearings 41A and 41B (first bearing 41A and second bearing 41B) are provided in the shaft through hole 30h. These bearings 41A and 41B are used to rotatably support the output shaft 42 of the second-stage planetary gear mechanism 31B, which will be discussed later, on the sealing plate portion 30b. For example, tapered roller bearings can be used as each of the bearings 41A and 41B.

[0045] A sealing member 21 is provided between the two bearings 41A and 41B in the shaft through hole 30h. Furthermore, an O-ring seal 22 is provided in the shaft through hole 30h at a position further outward than the first bearing 41A of the two bearings 41A and 41B, which is located on the side opposite to the motor 2. These sealing members 21 and O-ring seals 22 are used to ensure a tight seal between the sealing plate portion 30b and the output shaft 42.

[0046] The first-stage planetary gear mechanism 31A includes: a first sun gear 33, which is fixed to the outer peripheral surface of the motor shaft 2a and rotates integrally with the motor shaft 2a; a first planetary gear 34, which meshes with the first sun gear 33; and a first planetary gear carrier 35, which supports the first planetary gear 34.

[0047] Gear teeth 33g are formed on the outer peripheral surface of the first sun gear 33. Gear teeth 34g formed on the outer peripheral surface of the first planetary gear 34 mesh with the gear teeth 33g.

[0048] Multiple first planetary gears 34 are provided (e.g., three). Each first planetary gear 34 is arranged at equal intervals around the first sun gear 33. The gear teeth 34g of the first planetary gear 34 also mesh with the gear teeth 40g of the gear ring 40 located on the outer periphery.

[0049] An insertion hole 34h is formed in the radial center of the first planetary gear 34, extending along the central axis C. A bearing 36 is provided in this insertion hole 34h, and the first support shaft 37 of the first planetary gear carrier 35 (described later) is inserted through this bearing 36. As the bearing 36, a sliding bearing, for example, can be used.

[0050] The first planetary gear carrier 35 is independently provided with respect to the first planetary gear 34. The first planetary gear carrier 35 is located on the side opposite to the motor 2 (the side of the second-stage planetary gear mechanism 31B) relative to the first planetary gear 34. The first planetary gear carrier 35 is formed as a circular plate with its thickness along the direction of its central axis C. An opening 35h is formed in the radial center of the first planetary gear carrier 35. Gear teeth 35g are formed on the inner circumferential surface of the opening 35h.

[0051] A recess 35a is formed on the surface of the first planetary gear carrier 35 located on the side of the first planetary gear 34, surrounding the opening 35h. The first sun gear 33 is disposed in this recess 35a.

[0052] The first support shaft portion 37 protrudes from the surface of the first planetary gear carrier 35 located on the side of the first planetary gear 34. The first support shaft portion 37 is positioned corresponding to the first planetary gear 34 located near the outer periphery of the first planetary gear carrier 35. The first planetary gear 34 is rotatably supported by the first support shaft portion 37 via a bearing 36. The top end portion 37a of the first support shaft portion 37 passes through the insertion hole 34h of the first planetary gear 34 and protrudes beyond the first planetary gear 34.

[0053] A continuous circumferential groove 37b is formed at the top end 37a of the first support shaft portion 37. A C-shaped retaining ring 38 with an outer diameter larger than the inner diameter of the insertion hole 34h of the first planetary gear 34 is installed in the groove 37b. The retaining ring 38 prevents the first planetary gear 34 from detaching from the first support shaft portion 37. An annular thrust plate 39 is provided between the retaining ring 38 and the first planetary gear 34.

[0054] The second-stage planetary gear mechanism 31B includes: an output shaft 42, which is coaxially arranged with the rotation shaft 11; a second sun gear 43, which is arranged between the output shaft 42 and the first sun gear 33 in the first-stage planetary gear mechanism 31A; a second planetary gear 44, which meshes with the second sun gear 43; and a second planetary gear carrier 45, which supports the second planetary gear 44.

[0055] One end 42a of the output shaft 42 protrudes outward from the housing 30 via a shaft through hole 30h (bearings 41A, 41B) formed in the sealing plate portion 30b of the housing 30. The central axis of the output shaft 42 is aligned with the central axis C.

[0056] Gear teeth 43g are formed on the outer peripheral surface of the second sun gear 43. Gear teeth 35g of the first planetary gear carrier 35 in the first-stage planetary gear mechanism 31A mesh with gear teeth 43g. Gear teeth 44g formed on the outer peripheral surface of the second planetary gear 44 in the second-stage planetary gear mechanism 31B mesh with gear teeth 43g.

[0057] Multiple second planetary gears 44 are provided (e.g., three). Each second planetary gear 44 is equally spaced around the second sun gear 43. The gear teeth 44g of the second planetary gear 44 also mesh with the gear teeth 40g of the gear ring 40 located on the outer periphery. That is, the gear teeth 34g of the first planetary gear 34 in the first-stage planetary gear mechanism 31A arranged in the direction of the central axis C and the gear teeth 44g of the second planetary gear 44 in the second-stage planetary gear mechanism 31B mesh with the gear teeth 40g of the gear ring 40.

[0058] An insertion hole 44h is formed in the radial center of the second planetary gear 44, extending along the central axis C. A bearing 46 is provided in this insertion hole 44h. Furthermore, the second support shaft portion 47 of the second planetary gear carrier 45 (described later) is inserted into the insertion hole 44h, across the bearing 46. As the bearing 46, a sliding bearing, for example, can be used.

[0059] The second planetary gear carrier 45 is independently provided with respect to the second planetary gear 44. The second planetary gear carrier 45 is positioned relative to the second planetary gear 44 on the side of the housing 30 closest to the sealing plate portion 30b. The second planetary gear carrier 45 is formed as a circular plate with its thickness along the central axis C. An opening 45h is formed at the radial center of the second planetary gear carrier 45. Gear teeth 45g are formed on the inner circumferential surface of the opening 45h. The gear teeth 45g mesh with gear teeth 42g formed on the outer circumferential surface of the output shaft 42. Thus, the second planetary gear carrier 45 and the output shaft 42 rotate integrally.

[0060] The second support shaft portion (an example of the support shaft portion in the claim) 47 protrudes from the surface of the second planetary gear carrier 45 located on the side of the second planetary gear 44. The second support shaft portion 47 is provided at a position corresponding to the second planetary gear 44 located near the outer periphery of the second planetary gear carrier 45. The second planetary gear 44 is rotatably supported on the second support shaft portion 47 by means of a bearing 46.

[0061] A recess 45a is formed on the surface of the second planetary gear carrier 45 located on the side of the second planetary gear 44, surrounding the second support shaft portion 47. A first thrust plate 23 is disposed in this recess 45a. The first thrust plate 23 is formed in an annular shape, and the second support shaft portion 47 is inserted into the first thrust plate 23 to position the first thrust plate 23 in the recess 45a. The first thrust plate 23 is a plate subjected to the thrust force of the second planetary gear 44 toward the second planetary gear carrier 45.

[0062] Furthermore, an annular second thrust plate (an example of the thrust plate in the claims) 24 is disposed between the first planetary gear carrier 35 and each of the second planetary gears 44, and the annular second thrust plate 24 is inserted into the second support shaft portion 47. The second thrust plate 24 is used to prevent the second planetary gears 44 from falling off the second support shaft portion 47 and to prevent contact between the second planetary gears 44 and the first planetary gear carrier 35.

[0063] When the thickness of the second thrust plate 24 is set to T, the interval between the first planetary gear carrier 35 and the top surface 47a of the second support shaft 47 is set to G, the inner diameter of the second thrust plate 24 is set to D1, the inner diameter of the bearing 46 provided on the second support shaft 47 is set to D2, and the outer diameter of the bearing 46 is set to D3, these thicknesses T, intervals G, and diameters D1 to D3 satisfy the following formula:

[0064] T>G···Equation (1)

[0065] D2<D1<D3···Equation (2).

[0066] If we discuss equation (1) in detail, the thickness T is not particularly large relative to the interval G. The interval G is just a distance that ensures that the second support shaft 47 will not come into contact with the first planetary gear carrier 35 even if each planetary gear mechanism 31A, 31B wobbles slightly.

[0067] By satisfying equation (2), the entire inner periphery of the second thrust plate 24 is positioned to overlap with the bearing 46 when viewed from the direction of the central axis C.

[0068] For a motor 1 with a speed reducer, if the motor shaft 2a of the motor 2 rotates, the rotational force of the motor shaft 2a is input to the first-stage planetary gear mechanism 31A. That is, the first sun gear 33 rotates integrally with the motor shaft 2a, and the first planetary gear 34, which meshes with the first sun gear 33, rotates around the first support shaft 37 while also revolving around the radially outer side of the first sun gear 33. Through the revolution of the first planetary gear 34 around the first sun gear 33, the first planetary gear carrier 35 rotates around the rotation axis C.

[0069] The second sun gear 43 of the second-stage planetary gear mechanism 31B, which meshes with the gear teeth 35g of the first planetary gear carrier 35, rotates together with the first planetary gear carrier 35. If the second sun gear 43 rotates, the second planetary gear 44, which meshes with the second sun gear 43, rotates around the second support shaft 47 while simultaneously revolving around the radially outer side of the second sun gear 43. Through this revolution of the second planetary gear 44 around the second sun gear 43, the second planetary gear carrier 45 and the output shaft 42 rotate around their central axis.

[0070] In this way, the rotation of the rotating shaft 11 of motor 2 is reduced by the two-stage planetary gear mechanism 31A, 31B, and the output shaft 42 is driven to rotate.

[0071] A second thrust plate 24 is provided between the first planetary gear carrier 35 and the second planetary gear 44. The second thrust plate 24 is configured to be inserted into the second support shaft portion 47, thus limiting the radial displacement of the second thrust plate 24 by the second support shaft portion 47. The thickness T of the second thrust plate 24 and the distance G between the top surface 47a of the first planetary gear carrier 35 and the second support shaft portion 47 satisfy the above equation (1). Therefore, the length in the direction of the central axis C of the reduction mechanism 3 can be suppressed, and the second planetary gear 44 can be prevented from falling off the second support shaft portion 47 by means of the second thrust plate 24. Contact between the second planetary gear 44, the second support shaft portion 47 and the first planetary gear carrier 35 can be prevented. As a result, the second planetary gear 44 rotates (revolves) with almost no wobble. The planetary gear mechanisms 31A and 31B are driven smoothly.

[0072] The reduction mechanism 3 consists of two-stage planetary gear mechanisms 31A and 31B, and the displacement of the second thrust plate 24 in the direction of its central axis C is limited by the first planetary gear carrier 35. Therefore, the second thrust plate 24 can also be used to prevent the second planetary gear 44 from detaching from the second support shaft portion 47. Consequently, it is unnecessary to fix the second thrust plate 24 to the second support shaft portion 47, etc., thus simplifying the structure of the reduction mechanism 3.

[0073] However, lubricating oil is applied or filled to each planetary gear mechanism 31A and 31B to reduce the meshing resistance of each gear 33 to 44 and the sliding resistance of each bearing 36 and 46.

[0074] The second thrust plate 24, which is formed in an annular shape surrounding the second support shaft portion 47, is formed in accordance with the above formula (2). That is, the entire inner periphery of the second thrust plate 24 is positioned to overlap with the bearing 46 when viewed from the central axis C direction. Therefore, the second thrust plate 24 does not completely block one end of the bearing 46 in the central axis C direction, and a radial gap is formed between the second support shaft portion 47 and the second thrust plate 24. This allows lubricating oil to be distributed evenly to the bearing 46 and the insertion hole 44h through this gap.

[0075] A second thrust plate 24 is inserted (configured) into the second support shaft portion 47 of each second planetary gear 44. With this configuration, compared to, for example, the case where a large annular thrust plate is provided around the central axis C, the enlargement of the reduction mechanism 3 can be suppressed. The second planetary gear 44 can be reliably prevented from falling off from each of the second support shaft portions 47.

[0076] [Second Implementation]

[0077] Then, on the other hand, also refer to Figure 1 On one hand based on Figure 3 The second embodiment of the present invention will be described.

[0078] Figure 3 This is an enlarged view of the main part of the second-stage planetary gear mechanism 231B in the second embodiment. Figure 3 With the aforementioned Figure 2 Correspondingly, the same reference numerals are used for the same forms as in the first embodiment, and descriptions are omitted (the same applies to the following embodiments).

[0079] In the second embodiment, the motor 1 with a reducer has the same basic structure as the first embodiment described above (and the same for the following embodiments). This includes the motor 2 and the reduction mechanism 3 connected to the motor shaft 2a of the motor 2; the reduction mechanism 3 has two-stage planetary gear mechanisms 31A and 231B; a second thrust plate 224 is provided between the first planetary gear carrier 35 and the second planetary gear 244 and on each planetary gear 244; the thickness T of the second thrust plate 224 and the distance G between the first planetary gear carrier 35 and the top surface 47a of the second support shaft 47 satisfy the above formula (1).

[0080] like Figure 3 As shown, the difference between the first embodiment and the second embodiment is that the second thrust plate 24 and the second support shaft portion 47 of the first embodiment are different from the second thrust plate 224 and the second support shaft portion 247 of the second embodiment.

[0081] That is, a recess 247b is formed on the outer periphery of the top surface 247a of the second support shaft portion 247. The recess 247b is formed on the entire circumference of the second support shaft portion 247. The bottom surface 247c of the recess 247b is located on a plane that is approximately the same as the end surface 244a of the second planetary gear 244, or is located slightly closer to the first stage planetary gear mechanism 31A than the end surface 244a. In other words, the distance Gg between the end surface 244a of the first planetary gear carrier 35 and the second planetary gear 244 is the same as the distance Gj between the first planetary gear carrier 35 and the bottom surface 247c of the recess 247b, or slightly larger than that distance Gj.

[0082] The second thrust plate 224 is arranged across the recess 247b and the end face 244a of the second planetary gear 244. Therefore, the second thrust plate 224 is positioned above the bearing 46 (on the side of the first planetary gear carrier 35).

[0083] The second thrust plate 224 is formed in a shape that is radially contracted inward compared to the second thrust plate 24 in the first embodiment, corresponding to the recess 247b. The radial thickness of the second thrust plate 224 in the second embodiment is approximately the same as that of the second thrust plate 24 in the first embodiment.

[0084] Thus, according to the second embodiment described above, the same effect as that of the first embodiment described above is achieved. The inner peripheral surface of the second thrust plate 224 fits into the outer peripheral surface of the protrusion 247d formed on the top surface 247a of the second support shaft portion 247, thereby preventing the second thrust plate 224 from shaking and enabling the second thrust plate 224 to be stably positioned.

[0085] The distance Gg between the end faces 244a of the first planetary gear carrier 35 and the second planetary gear 244 is the same as, or slightly larger than, the distance Gj between the first planetary gear carrier 35 and the bottom face 247c of the recess 247b. Therefore, even when, for example, the second thrust plate 224 is pressed against the second support shaft portion 247, the sliding friction resistance between the second thrust plate 224 and the second planetary gear 244 can be prevented from increasing. Consequently, the rotational resistance of the second planetary gear 244 can be reduced, allowing the second planetary gear 244 to rotate smoothly at all times.

[0086] Furthermore, in the second embodiment described above, the radial thickness of the second thrust plate 224 in the second embodiment is approximately the same as the radial thickness of the second thrust plate 24 in the first embodiment. However, this is not a limitation; the outer diameter of the second thrust plate 224 in the second embodiment may also be approximately the same as the outer diameter of the second thrust plate 24 in the first embodiment. With this configuration, the area at both ends of the second thrust plate 224 in the thickness direction can be increased. Therefore, the surface pressure when the second thrust plate 224 contacts each part can be reduced. Consequently, wear on the second thrust plate 224 and the parts in contact with it can be suppressed.

[0087] [Third Implementation]

[0088] Next, based on Figure 4 The third embodiment of the present invention will be described.

[0089] Figure 4 This is an enlarged view of the main part of the second-stage planetary gear mechanism 331B in the third embodiment. Figure 4 With the aforementioned Figure 2 Correspondingly.

[0090] like Figure 4 As shown, the difference between the first embodiment and the third embodiment lies in the fact that the second planetary gear 44 of the first embodiment is different from the second planetary gear 344 of the third embodiment.

[0091] That is, a recess 25 is formed on the end face 344a of the second planetary gear 344 located on the side of the first planetary gear carrier 35, at a position radially inward compared to the gear teeth 44g. The recess 25 is formed in an annular shape when viewed from the central axis C. The inner periphery of the recess 25 communicates with the insertion hole 44h. The recess 25 thus formed has an inner surface 25b facing radially inward. The top surface 47a of the second support shaft portion 47, which supports the second planetary gear 344 for rotation, is located on a plane substantially the same as the end face 344a of the second planetary gear 344.

[0092] The diameter D4 of the inner surface 25b of the recess 25 is approximately the same as or slightly larger than the outer diameter D5 of the second thrust plate 24. That is, the inner surface 25b of the recess 25 has the function of restricting the radial displacement of the second thrust plate 24.

[0093] Therefore, according to the third embodiment described above, the same effect as that of the first embodiment described above is achieved. The inner periphery of the recess 25 communicates with the insertion hole 44h. Therefore, lubricating oil can be distributed evenly throughout the insertion hole 44h and the recess 25 without any leakage.

[0094] By utilizing the inner surface 25b of the recess 25, the radial displacement of the second thrust plate 24 can be easily restricted. Therefore, the position of the second thrust plate 24 can be stabilized.

[0095] [Fourth Implementation]

[0096] Next, based on Figure 5 The fourth embodiment of the present invention will now be described.

[0097] Figure 5 This is a top view obtained by observing the second thrust plate 424 in the fourth embodiment from the direction of the central axis C.

[0098] like Figure 5 As shown, the difference between the first embodiment and the fourth embodiment lies in the fact that the second thrust plate 24 of the first embodiment is different from the second thrust plate 424 of the fourth embodiment.

[0099] That is, a plurality of recesses (an example of the fluid passage in the claim) 428 are formed on the inner periphery of the second thrust plate 424. The plurality of recesses 428 are arranged at equal intervals in the circumferential direction.

[0100] Based on this structure, lubricating oil flows smoothly through multiple recesses 428 in the thickness direction of the second thrust plate 424. That is, the multiple recesses 428 function as fluid passages for smoothly distributing lubricating oil in the thickness direction of the second thrust plate 424.

[0101] Therefore, according to the fourth embodiment described above, in addition to having the same effect as the first embodiment described above, it is possible to further facilitate the distribution of lubricating oil throughout the entire reduction gear 3.

[0102] [Fifth Implementation]

[0103] Next, based on Figure 6 The fifth embodiment of the present invention will be described.

[0104] Figure 6 This is a top view obtained by observing the second thrust plate 524 in the fifth embodiment from the direction of the central axis C.

[0105] like Figure 6 As shown, the difference between the fourth and fifth embodiments lies in the fact that the second thrust plate 424 of the fourth embodiment is different from the second thrust plate 524 of the fifth embodiment.

[0106] That is, in the fifth embodiment, a plurality of holes 528 (an example of a fluid passage in the claims) extending in the thickness direction are formed around the entire circumference of the second thrust plate 524 to replace the recess 428 of the fourth embodiment. The plurality of holes 528 are arranged at equal intervals in the circumferential direction.

[0107] Based on this structure, lubricating oil flows smoothly through multiple holes 528 in the thickness direction of the second thrust plate 524. That is, the multiple holes 528 function as fluid passages for smoothly distributing lubricating oil in the thickness direction of the second thrust plate 524.

[0108] Therefore, according to the fifth embodiment described above, it achieves the same effect as the fourth embodiment described above.

[0109] Furthermore, the present invention is not limited to the embodiments described above, and includes embodiments with various modifications made to the embodiments described above without departing from the spirit of the present invention.

[0110] For example, in the above embodiment, the case where a motor 2 is provided as the drive source for transmitting driving force to the reduction mechanism 3 has been described. However, it is not limited to this; any drive source that transmits driving force to the reduction mechanism 3 can be provided. For example, an engine or the like can be used instead of a motor 2.

[0111] Furthermore, the case of an electric motor, in which motor 2 is connected to an external power source (not shown) and is supplied with electricity from that external power source to rotate the motor shaft 2a, has been described. However, it is not limited to this; a hydraulic motor may also be used as motor 2.

[0112] In the above embodiments, the case in which three planetary gears 34 and 44 are provided in each planetary gear mechanism 31A and 31B is described, for example. However, it is not limited to this, and the number of planetary gears 34 and 44 in each planetary gear mechanism 31A and 31B may be at least one.

[0113] In the above embodiments, the reduction mechanism 3 has been described as having, for example, a two-stage planetary gear mechanism 31A, 31B. However, it is not limited to this; the reduction mechanism 3 may have at least a single-stage planetary gear mechanism. For example, if the planetary gear mechanism is single-stage, a limiting part can be provided instead of the first planetary gear carrier 35 that limits the displacement of the second thrust plates 24, 224, 424, 524 in the direction of the central axis C. The second thrust plates 24, 224, 424, 524 are used to prevent the second planetary gears 44, 244, 344 from falling off the second support shaft portions 47, 247.

[0114] In the above embodiments, the second thrust plates 24, 224, 424, and 524 were described as being formed in annular shape. However, this is not a limitation; the shapes of the second thrust plates 24, 224, 424, and 524 can be annular when viewed from the central axis C. That is, the shapes of the outer and inner peripheries of the second thrust plates 24, 224, 424, and 524 can take into account their relationship with other parts and can be various shapes, such as polygonal, elliptical, curved, or straight and curved shapes when viewed from the direction of the central axis C. The shapes of the second thrust plates 24, 224, 424, and 524 do not need to be symmetrical about the second support shaft portions 47 and 247; they can also be asymmetrical.

[0115] Furthermore, the second thrust plates 24, 224, 424, and 524 may not be formed as plates of uniform thickness. In this case, the maximum thickness Tmax of the portion of the second thrust plates 24, 224, 424, and 524 with the largest thickness T satisfies the above formula (1). The maximum thickness Tmax refers to the maximum thickness between the portion of the second thrust plates 24, 224, 424, and 524 that contacts the first planetary gear carrier 35 and the portion that contacts the second planetary gears 44, 244, and 344 or the bottom surface 247c of the recess 247b formed in the second support shaft portion 247. The second thrust plates 24, 224, 424, and 524 with uniform thickness are defined as T = Tmax.

[0116] Industrial availability

[0117] According to the present invention, even when a thrust plate is provided to prevent undesirable contact between components, the construction can be simplified. Therefore, it has industrial applicability.

Claims

1. A speed reduction mechanism, wherein, This deceleration mechanism has the following features: A planetary gear mechanism comprising: a sun gear; planetary gears meshing with the sun gear; and a planetary gear carrier having a support shaft portion that supports the planetary gears for rotational movement. A limiting part that prevents the planetary gear from detaching from the support shaft; and An annular thrust plate is disposed between the planetary gear and the limiting part, and the top surface of the support shaft on the limiting part side is inserted into its inner side. The maximum thickness of the thickest part of the thrust plate is greater than the distance between the top surface of the support shaft on the side near the limiting part and the limiting part. The thrust plate protrudes from the top end of the support shaft toward the limiting portion.

2. The deceleration mechanism according to claim 1, wherein, The planetary gear has: an insertion hole for the support shaft portion to be inserted; and a recess formed on the inner circumference of the planetary gear on one end face near the limiting portion, in communication with the insertion hole. The thrust plate is disposed in the recess. The recess has an inner surface that restricts radial displacement of the thrust plate.

3. The deceleration mechanism according to claim 2, wherein, The reduction mechanism has a bearing that fits into the outer peripheral surface of the support shaft and into the inner peripheral surface of the insertion hole of the planetary gear, for supporting the planetary gear to rotate freely relative to the support shaft. The thrust plate is positioned in the axial direction of the support shaft, overlapping the bearing around its entire circumference.

4. The speed reduction mechanism according to any one of claims 1 to 3, wherein, The thrust plate has a fluid passage formed in such a way that it extends axially through the support shaft, allowing fluid to pass through.

5. The speed reduction mechanism according to any one of claims 1 to 3, wherein, The planetary gear mechanism has multiple planetary gears and a support shaft. Each of the planetary gears is provided with a thrust plate.

6. The speed reduction mechanism according to any one of claims 1 to 3, wherein, A plurality of planetary gear mechanisms are arranged along the axial direction of the support shaft. The limiting part is the planetary gear carrier, which is disposed between the planetary gears of one planetary gear mechanism and the planetary gears of the other planetary gear mechanism in the planetary gear mechanisms that are adjacent to each other in the axial direction.

7. A speed reduction mechanism, wherein, This deceleration mechanism has the following features: Multiple planetary gear mechanisms; and A thrust plate, which is disposed between the two planetary gear mechanisms, The planetary gear mechanism has the following features: Sun gear; Planetary gears that mesh with the sun gear and revolve around the sun gear due to the rotation of the sun gear; A planetary gear carrier is provided with a support shaft that supports the planetary gears so that they can rotate freely about the central axis of the sun gear. as well as A bearing, fitted onto the outer circumferential surface of the support shaft, is used to support the planetary gear in a rotatable manner on the support shaft. Multiple planetary gear mechanisms are arranged along the axial direction of the support shaft, and in planetary gear mechanisms that are adjacent to each other in the axial direction, the planetary gears of one planetary gear mechanism and the planetary gear carriers of another planetary gear mechanism are arranged in an adjacent manner. The thrust plate is formed as an annular shape, inserted on the inner side by the top surface of the support shaft of one planetary gear mechanism near the planetary gear carrier of the other planetary gear mechanism. It is disposed between the planetary gear of one planetary gear mechanism and the planetary gear carrier of the other planetary gear mechanism, and is positioned such that the thrust plate overlaps with the bearing circumferentially on the support shaft. The maximum thickness of the thickest part of the thrust plate is greater than the distance between the top surface of the support shaft of one planetary gear mechanism and the planetary gear carrier of the other planetary gear mechanism. The thrust plate protrudes from the top end of the support shaft of one planetary gear mechanism toward the planetary gear carrier side of the other planetary gear mechanism.

8. A driving device, wherein, The drive unit has: Speed ​​reduction mechanism; and The drive source transmits driving force to the reduction mechanism. The deceleration mechanism includes: A planetary gear mechanism comprising: a sun gear; planetary gears meshing with the sun gear and revolving around the sun gear due to the rotation of the sun gear; and a planetary gear carrier having a protruding support shaft portion supporting the planetary gears so as to be rotatable, the planetary gear carrier being rotatable about the central axis of the sun gear. A limiting part that prevents the planetary gear from detaching from the support shaft; and An annular thrust plate is disposed between the planetary gear and the limiting part, and the top surface of the support shaft on the limiting part side is inserted into its inner side. The maximum thickness of the thickest part of the thrust plate is greater than the distance between the top surface of the support shaft on the side near the limiting part and the limiting part. The thrust plate protrudes from the top end of the support shaft toward the limiting portion.

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