Transmission

Abstract

A transmission (100) comprises a tubular rotating housing (15) that houses a planetary gear mechanism (40) and that rotates when output rotation, the speed of which has been changed, is transmitted thereto. The planetary gear mechanism (40) has a plurality of annular second planetary gears (53) which mesh with both a second sun gear (51) and an inner gear (42), and a plurality of second planetary carriers (54) which support the second planetary gears (53). Provided to the second planetary carriers (54) are second plates (80) that at least partially cover the second planetary gears (53), that are fixed to the second planetary carriers (54), and that prevent the second planetary gears (53) from slipping off from the second planetary carriers (54). There are a plurality of the second plates (80), and each second plate is fixed to two or more second planetary carriers (54).

Description

Transmission

[0001] The present invention relates to a transmission.

[0002] JP 2017-116055A discloses a transmission including a fixed housing that accommodates a hydraulic motor, a speed change mechanism that changes the output rotation of the hydraulic motor shaft, a rotating housing that accommodates the speed change mechanism and rotates by receiving the changed output rotation, and a cover that closes the open end of the rotating housing. The transmission described in JP 2017-116055A is a planetary gear mechanism that includes a sun gear provided on the shaft of the hydraulic motor, an inner gear provided on the inner wall of the rotating housing, and multiple planetary gears that mesh with both the sun gear and the inner gear. A main body that supports the planetary gears is provided with a retaining plate and a fixing member that fixes the plate to the main body, and the planetary gears are prevented from coming off by covering a portion of the planetary gear with the plate.

[0003] In a transmission such as that described in JP2017-116055A, the plate is formed in an annular shape and is formed by punching out a base material using a press, etc. As a result, a large amount of scrap material is discarded when the plate is formed, which may increase the manufacturing cost of the transmission.

[0004] The present invention aims to reduce the manufacturing costs of a transmission.

[0005] According to one aspect of the present invention, there is provided a transmission comprising: a shaft to which output rotation of a drive source is transmitted; a planetary gear mechanism connected to the shaft and changing the speed of the output rotation of the drive source; and a cylindrical rotating housing that houses the planetary gear mechanism and rotates by the changed output rotation transmitted thereto, wherein the planetary gear mechanism comprises a sun gear to which power from the drive source is transmitted via the shaft; an inner gear formed on the inner surface of the rotating housing; a plurality of annular planetary gears having hollow portions that mesh with both the sun gear and the inner gear; and a plurality of support portions that are inserted into the hollow portions of the plurality of planetary gears and support the planetary gears, wherein the support portions are provided with plates that cover at least a portion of the planetary gears and are fixed to the support portions to prevent the planetary gears from coming off the support portions, and the plates consist of a plurality of plates, each fixed across two or more of the support portions.

[0006] FIG. 1 is a cross-sectional view of a transmission-equipped motor including a transmission according to an embodiment of the present invention. FIG. 2 is a plan view of a second sun gear, a second planetary gear, and a second plate. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 4 is a diagram illustrating the molding process when the second plate is formed by punching out using press molding. FIG. 5 is a plan view of a planetary gear mechanism according to a second modification of the present invention, shown in correspondence with FIG. 2. FIG. 6 is a plan view of a planetary gear mechanism according to a third modification of the present invention, shown in correspondence with FIG. 2. FIG. 7 is a diagram illustrating the molding process when the second plate is formed by punching out using press molding according to the third modification of the present invention. FIG. 8 is a diagram illustrating the molding process when the second plate is formed by punching out using press molding according to a comparative example of the embodiment of the present invention. FIG. 9 is a plan view of a planetary gear mechanism according to a fourth modification of the present invention, shown in correspondence with FIG. 2. FIG. 10 is a plan view of a planetary gear mechanism according to the fourth modification of the present invention, shown in correspondence with FIG. 2. FIG. 11 is a plan view of a planetary gear mechanism according to a fifth modified example of the embodiment of the present invention, and corresponds to FIG. 2.

[0007] Hereinafter, a transmission 100 according to an embodiment of the present invention and a transmission-equipped motor 101 as a drive device including the same will be described with reference to the drawings.

[0008] The transmission-equipped motor 101 is mounted on the axle of a crawler-type working machine such as a hydraulic excavator to drive the crawler belt. As shown in Figure 1, the transmission-equipped motor 101 includes a hydraulic motor 20 as a drive source, and a transmission 100 connected to a motor shaft (not shown) of the hydraulic motor 20 to reduce the output rotation of the motor shaft.

[0009] The transmission 100 includes a planetary gear mechanism 40 as a speed change mechanism that changes the output rotation of the hydraulic motor 20, a fixed housing 10 that houses the hydraulic motor 20, a cylindrical rotating housing 15 that houses the planetary gear mechanism 40 and rotates by receiving the changed output rotation, and a cover 60 that is provided on the inner periphery of an open end 15a of the rotating housing 15 and closes the open end 15a of the rotating housing 15. The specific configuration of the planetary gear mechanism 40 will be described later. The fixed housing 10, the rotating housing 15, and the cover 60 form a housing 1 of the transmission 100.

[0010] The rotating housing 15 rotates relative to the fixed housing 10. An open end 15a of the rotating housing 15 opens on the opposite side of the planetary gear mechanism 40 from the hydraulic motor 20 (the right side in FIG. 1). A sprocket (not shown) is connected to the outer circumferential surface of the rotating housing 15. When the rotating housing 15 and the sprocket rotate together, a crawler belt (not shown) that meshes with the sprocket circulates, causing the vehicle to move.

[0011] The fixed housing 10 and the rotating housing 15 are arranged inside the path along which the crawler belt circulates. The rotating housing 15 is rotatably supported via bearings 3 relative to the fixed housing 10, which is connected to the vehicle body 102, and rotates around its central axis.

[0012] The fixed housing 10 has a main body 11 and a fixed flange 12 formed to protrude from the outer peripheral surface of the main body 11 and attached to the vehicle body 102 .

[0013] The cover 60 is formed in a disk shape and is attached to the inner circumferential surface of the open end 15a of the rotary housing 15. A plug 61 is provided in the center of the cover 60. As will be described later, the plug 61 receives a thrust load generated in the planetary gear mechanism 40 via a first plate 70.

[0014] The gear chamber 4 that houses the planetary gear mechanism 40 is defined by the inner surface of the rotating housing 15, the outer surface of the main body 11 of the fixed housing 10, and the inner surface of the cover 60. Lubricating oil is sealed in the gear chamber 4 as a lubricant that can lubricate the planetary gear mechanism 40.

[0015] A rotary flange 16 is formed on the rotary housing 15 and protrudes annularly from the outer circumferential surface. The sprocket is fastened to the rotary flange 16 with a plurality of bolts (not shown) and rotates together with the rotary housing 15.

[0016] A floating seal 5 is provided between the fixed housing 10 and the rotating housing 15. The floating seal 5 seals the hydraulic oil in the transmission 100 so that it does not leak out to the outside when the rotating housing 15 is rotating, and also prevents foreign matter from entering the transmission 100 from the outside.

[0017] In addition, a labyrinth seal 6 is formed between the fixed housing 10 and the rotating housing 15 to prevent foreign matter such as mud from entering from the outside of the floating seal 5. The labyrinth seal 6 is formed by the gap between the opposing end faces of the fixed housing 10 and the rotating housing 15.

[0018] The hydraulic motor 20 is provided inside the main body 11 of the fixed housing 10. The hydraulic motor 20 is, for example, a swash plate type piston motor that is rotationally driven by the supply and discharge of hydraulic oil (hydraulic fluid). Note that the motor may be a type other than a hydraulic motor, and for example, an electric motor may be used. Since the hydraulic motor 20 can have a known configuration, it is illustrated in a simplified form in FIG. 1 and a detailed description thereof will be omitted in this specification.

[0019] The transmission 100 includes a drive shaft 31 that is coaxially connected to the motor shaft of the hydraulic motor 20 and transmits the output rotation of the motor shaft. The planetary gear mechanism 40 is connected to the drive shaft 31 and reduces the output rotation of the motor shaft of the hydraulic motor 20 before transmitting it to the rotating housing 15. The drive shaft 31 and the motor shaft of the hydraulic motor 20 are connected by, for example, a spline connection. The drive shaft 31 and the motor shaft of the hydraulic motor 20 may be integrally configured. Note that, because the rotating housing 15 and the drive shaft 31 are arranged coaxially, hereinafter the axial direction of the rotating housing 15 and the drive shaft 31 will also be simply referred to as the "axial direction," and the radial direction of the rotating housing 15 and the drive shaft 31 will also be simply referred to as the "radial direction."

[0020] The planetary gear mechanism 40 comprises a first sun gear 41 to which power from the hydraulic motor 20 is transmitted via the drive shaft 31, an inner gear 42 formed on the inner surface of the rotating housing 15, a plurality of annular first planetary gears 43 that mesh with both the first sun gear 41 and the inner gear 42, a plurality of first planetary carriers 44 that are inserted into the hollow portions of the plurality of first planetary gears 43 and support the first planetary gears 43, a second sun gear 51 that meshes with each of the plurality of first planetary carriers 44, a plurality of annular second planetary gears 53 that mesh with both the second sun gear 51 and the inner gear 42, and a plurality of second planetary carriers 54 that are inserted into the hollow portions of the plurality of second planetary gears 53 and support the second planetary gears 53. In this embodiment, the second sun gear 51, the second planetary gear 53, and the second planetary carrier 54 correspond to the "sun gear," "planetary gear," and "support portion" in the claims.

[0021] The multiple first planetary carriers 44 are spaced apart from one another in the circumferential direction, and the multiple second planetary carriers 54 are also spaced apart from one another in the circumferential direction. The second planetary carrier 54 is mounted via a fixing member (not shown) or the like on the end face of the main body 11 of the fixed housing 10 facing the cover 60. The first sun gear 41, the first planetary gears 43, and the first planetary carrier 44 form a first-stage carrier of the planetary gear mechanism 40, and the second sun gear 51, the second planetary gears 53, and the second planetary carrier 54 form a second-stage carrier of the planetary gear mechanism 40. The first-stage carrier is located closer to the cover 60 than the second-stage carrier. The end faces of the first planetary gears 43 and the first planetary carrier 44 facing the cover 60 are flush with each other, and the end faces of the second planetary gears 53 and the second planetary carrier 54 facing the cover 60 are flush with each other. In this embodiment, four second planetary gears 53 are provided (see FIG. 2 ). The second planetary gear 53 is supported by the second planetary carrier 54 via an annular needle bearing 57 and an annular inner bearing 58 provided inside the needle bearing 57 .

[0022] When the motor shaft of the hydraulic motor 20 is driven to rotate, the drive shaft 31 connected to the motor shaft rotates in accordance with the rotation of the motor shaft. The output rotation of the drive shaft 31 acts on the inner gear 42 via the first sun gear 41 and first planetary gear 43, and the second-stage second sun gear 51 and second planetary gear 53, and is then transmitted to the rotating housing 15. In the transmission 100 of this embodiment, the first planetary gear 43 and the inner gear 42, and the second planetary gear 53 and the inner gear 42, are meshed obliquely with each other relative to the axial direction. Therefore, a thrust load (a load along the axial direction) is generated in the planetary gear mechanism 40 due to a reaction force of the forces acting on the inner gear 42 from the first planetary gear 43 and the second planetary gear 53. Therefore, a force acts on the first planetary gear 43 to disengage from the first planetary carrier 44 , and a force acts on the second planetary gear 53 to disengage from the second planetary carrier 54 .

[0023] Therefore, in the planetary gear mechanism 40, a first plate 70 that covers a portion of the first planetary gear 43 and prevents the first planetary gear 43 from coming off the first planetary carrier 44 is fixed to the first planetary carrier 44 by first screw members 46. Also, a second plate 80 that covers a portion of the second planetary gear 53 and prevents the second planetary gear 53 from coming off the second planetary carrier 54 is fixed to the second planetary carrier 54 by second screw members 56. In this embodiment, the second plate 80 corresponds to the "plate" in the claims.

[0024] First, the first plate 70 will be described.

[0025] The first plate 70 is formed in a disk shape by stamping out a single plate using press molding. The first plate 70 is provided across the drive shaft 31, the first sun gear 41, the first planetary carrier 44, and the end faces of each first planetary gear 43 that face the cover 60. The first plate 70 is provided to cover the entire hollow portion of the first planetary gear 43 and also to cover a portion of the first planetary gear 43. Specifically, in the cross-sectional view shown in FIG. 1 , the first plate 70 covers the entire first planetary gear 43 on the drive shaft 31 side of the hollow portion and a portion of the first planetary gear 43 on the opposite side of the hollow portion from the drive shaft 31.

[0026] By fixing the first plate 70 to the first planetary carrier 44, the axial movement of the first planetary gear 43 is restricted by the first plate 70, and the first planetary gear 43 is prevented from coming off the first planetary carrier 44. Furthermore, the thrust load generated in the planetary gear mechanism 40 acts on the plug 61 provided in the cover 60 via the single first plate 70 having a large area. The thrust load of the planetary gear mechanism 40 that the plug 61 receives is equalized by the first plate 70, so the first plate 70 and the plug 61 come into surface contact without making a one-sided contact. This prevents uneven wear of the first plate 70 and the plug 61.

[0027] Next, the second plate 80 will be described.

[0028] FIG. 2 is a plan view of the second sun gear 51, the second planetary gear 53, and the second plate 80. The inner gear 42 and the second screw member 56 are omitted from FIG. 2 and FIGS. 5, 6, 9-11 described below. As shown in FIGS. 1 and 2, the second plate 80 is provided on the end surfaces of the second planetary carrier 54 and the second planetary gear 53 facing the cover 60. As shown in FIG. 2, multiple second plates 80 are provided, each fixed across two circumferentially adjacent second planetary carriers 54. The second plates 80 are provided contiguously with one another so as to surround the second sun gear 51 when viewed in the axial direction of the drive shaft 31. Specifically, the transmission 100 of this embodiment is provided with two second plates 80 of the same shape. By making each second plate 80 the same shape (a common part), the number of types of parts to be inventory managed can be kept constant. Hereinafter, for convenience, the second plate 80 on the right in Fig. 2 will also be referred to as the second plate 80a, and the second plate 80 on the left in Fig. 2 will also be referred to as the second plate 80b. Also, of the second planetary gears 53, the upper one in Fig. 2 will also be referred to as the second planetary gear 53a, the right one as the second planetary gear 53b, the lower one as the second planetary gear 53c, and the left one as the second planetary gear 53d.

[0029] The second plates 80a, 80b are formed by punching out a single plate using press molding. The second plates 80a, 80b have V-shaped main bodies 81a, 81b, and one end portion 82a, 82b is bent to form step portions 83a, 83b in the plate thickness direction.

[0030] The main body portions 81a, 81b are formed so that the width of the linear portions is uniform. Specifically, the main body portion 81a has linear portions 91a, 92a on an inner circumferential surface 86a on the second sun gear 51 side and an outer circumferential surface 87a on the opposite side to the second sun gear 51, respectively, and the linear portions 91a, 92a are formed parallel to each other (with the same shape). The main body portion 81b has linear portions 91b, 92b on an inner circumferential surface 86b on the second sun gear 51 side and an outer circumferential surface 87b on the opposite side to the second sun gear 51, respectively, and the linear portions 91b, 92b are formed parallel to each other (with the same shape). The main body portions 81a, 81b are formed by cutting out root portions 88a, 88b, which are the apexes of the V-shape. As shown in FIG. 3, the step portions 83a, 83b are formed in a stepped shape and higher than the main body portions 81a, 81b. The step portions 83a, 83b have the same thickness as the main body portions 81a, 81b, and when the second plates 80a, 80b are fixed to the second planetary carrier 54, a space is formed between the step portions 83a, 83b and the second planetary carrier 54. No step is formed on the other ends 84a, 84b of the second plates 80a, 80b. As shown in FIG. 2 , the second plate 80a is provided such that the center of the main body portion 81a is located on the second planetary gear 53b, one end 82a (step portion 83a) is located on the second planetary gear 53a, and the other end 84a is located on the second planetary gear 53c. The second plate 80b is provided such that the center of the main body portion 81b is located on the second planetary gear 53d, one end 82b (step portion 83b) is located on the second planetary gear 53c, and the other end 84b is located on the second planetary gear 53a.

[0031] 2 and 3 , the second plates 80a, 80b are arranged such that the other end 84b of the second plate 80b fits into the space below the stepped step 83a of the second plate 80a, and the other end 84a of the second plate 80a fits into the space below the stepped step 83b of the second plate 80b, so that the ends of the second plates 80a, 80b overlap each other. As a result, the second sun gear 51 is surrounded in a quadrangular shape by the second plates 80a, 80b, and each of the second plates 80a, 80b prevents the three second planetary gears 53 from coming off. In this state, the two adjacent second plates 80a, 80b are continuous, and the second planetary gear 53 sides of the second plates 80a, 80b are flat. In other words, the main body 81 a of the second plate 80 a, the other end 84 b of the second plate 80 b, the main body 81 b of the second plate 80 b, and the other end 84 a of the second plate 80 a are located on the same plane. A plurality of fastening holes 55 into which the second screw members 56 are fastened are formed in the second plates 80 a and 80 b.

[0032] FIG. 4 is a diagram illustrating the molding process used to form the second plate 80 by punching it out using a press. In this embodiment, multiple second plates 80 have the same shape. Furthermore, the inner and outer shapes of each second plate 80 are formed to partially correspond to each other. Specifically, as described above, the inner circumferential surface 86 (linear portion 91) and the outer circumferential surface 87 (linear portion 92) of the main body portion 81 are formed parallel to each other (to have the same shape) in the linear portion of the main body portion 81. Therefore, as shown in FIG. 4, multiple second plates 80 can be formed by arranging them side by side with their inner circumferential surfaces 86 and outer circumferential surfaces 87 in contact with each other. As a result, the scrap material discarded during the formation of the second plate 80 can be minimized to include only the notched portion of the base portion 88 of the main body portion 81, the portion between the one end portions 82, the portion between the other end portions 84, and the fastening holes 55.

[0033] As described above, in the transmission 100 of this embodiment, multiple second plates 80 are provided on the second planetary carrier 54 to prevent the second planetary gear 53 from slipping out. Therefore, compared to when a single annular second plate 580 is provided, as shown in FIG. 8 , each second plate 80 can be made smaller, and less scrap material is discarded during the formation of the second plate 80. Specifically, with a single annular second plate 580, a large amount of scrap material is generated in the hollow portion A of the second plate 580 and in the space B between the second plates 580. However, in the transmission 100 of this embodiment, because each second plate 80 is small, the space where scrap material is generated can be reduced. This reduces the manufacturing cost of the transmission 100. Furthermore, because each second plate 80 is small, not only can the storage space required for inventory in a warehouse or the like be reduced, but also the number of second plates 80 that can be processed at one time during heat treatment or surface treatment can be increased, thereby further reducing the manufacturing cost of the transmission 100.

[0034] Furthermore, in the transmission 100, the inner shape (inner circumferential surface 86) and the outer shape (outer circumferential surface 87) of each of the multiple second plates 80 are formed to have partially corresponding shapes. In other words, the inner circumferential surface 86 and the outer circumferential surface 87 of each second plate 80 each have linear portions 91, 92, and the linear portions 91, 92 are formed to have partially corresponding shapes (the same shape). Therefore, when the multiple second plates 80 are punched out by press molding, the multiple second plates 80 can be formed side by side. This reduces waste material. In other words, "the inner circumferential surface 86 and the outer circumferential surface 87 of each of the multiple second plates 80 are formed to have partially corresponding shapes" means that, as shown in FIG. 4 , when a single plate is punched out by press molding to form the multiple second plates 80, the inner circumferential surface 86 (linear portion 91) and the outer circumferential surface 87 (linear portion 92) of adjacent second plates 80 are formed side by side and in contact with each other. By forming the plurality of second plates 80 side by side and in contact with each other, the number of cuts during press molding is reduced, thereby improving the workability of the second plates 80. Note that, as long as the plurality of second plates 80 can be arranged in succession, the second plates 80 do not necessarily need to be formed in contact with each other.

[0035] Furthermore, in the transmission 100, a step 83 is formed in the plate thickness direction at one end 82 of each of the multiple second plates 80, so even if the ends (ends 82 and 84) of the second plates 80 are overlapped, the step 83 makes it possible to flatten the side facing the second planetary gear 53. This prevents the second plates 80 from coming into partial contact with the second planetary gear 53, needle bearing 57, inner bearing 58, etc., and improves the durability of the transmission 100.

[0036] Furthermore, when the transmission 100 is in operation, the multiple second plates 80 receive a rotational load (rotational moment) from the second planetary gear 53 and the second screw member 56 with which they come into contact. This may cause the second plates 80 to tilt, resulting in uneven contact with the second planetary gear 53, the needle bearing 57, the inner bearing 58, etc. However, in the transmission 100 of this embodiment, the multiple second plates 80 are fixed at at least two locations. This makes the second plates 80 less likely to tilt. Furthermore, because the multiple second plates 80 are continuously arranged in an annular shape to surround the second sun gear 51, the second plates 80 are even less likely to tilt. This prevents uneven contact of the second plates 80 and improves durability. Furthermore, because the rigidity of the second plates 80 is higher than when each second plate 80 is fixed at one location, the multiple second plates 80 can also be made thinner.

[0037] According to the present embodiment described above, the following advantageous effects are achieved.

[0038] In the transmission 100, a plurality of second plates 80 are provided on the second planetary carrier 54 to prevent the second planetary gear 53 from coming off. This allows each second plate 80 to be smaller, and reduces the amount of scrap material that is discarded when forming the second plates 80. This allows the manufacturing cost of the transmission 100 to be reduced.

[0039] Next, modifications of the above embodiment will be described. The following modifications are also within the scope of the present invention, and it is also possible to combine the configurations described in the following different modifications.

[0040] <Variation 1> In the above embodiment, one end 82 of each of the second plates 80 is bent to form a step 83 that is higher than the main body 81. The other end 84 of another second plate 80 fits into the space below the step 83, flattening the second planetary gear 53 side. However, the present invention is not limited to this. Instead, one end 82 of each of the second plates 80 may be unbent. Instead, one end 82 of each of the second plates 80 may be cut out in the thickness direction to form a step 83 toward the second planetary gear 53, and the other end 84 may be cut out on the opposite side to the second planetary gear 53, so that the step portions mesh with each other. This configuration also reduces waste material. Furthermore, the other end 84 fits into the space between the step 83 and the second planetary carrier 54, so that the respective end portions 82, 84 overlap each other. This flattens the second planetary gear 53 side, improving the durability of the transmission 100.

[0041] <Modification 2> In the above embodiment, the plurality of second plates 80 have a step portion 83 formed at one end portion 82, and the respective ends 82, 84 are provided so as to overlap each other. However, this is not limited to this. As shown in Fig. 5, the plurality of second plates 180 may be provided so as to be continuous with each other, with the respective ends 182, 184 abutting each other, without the step portion 83. In this configuration, one end 182a of the second plate 180a and the other end 184b of the second plate 180b are abutted against each other, and the other end 184a of the second plate 180a and one end 182b of the second plate 180b are abutted against each other. Furthermore, a fastening hole 55 corresponding to the second planetary gear 53a is provided between one end 182a of the second plate 180a and the other end 184b of the second plate 180b, and a fastening hole 55 corresponding to the second planetary gear 53c is provided between the other end 184a of the second plate 180a and one end 182b of the second plate 180b. The second plates 180a, 180b are connected by fastening second screw members 56 into these fastening holes 55. Even with this configuration, scrap material can be reduced, the multiple second plates 180 are less likely to tilt, and the durability of the multiple second plates 180 is improved. Note that a protrusion or a recess for accommodating the protrusion may be provided at the butted portion of the second plates 180a, 180b.

[0042] <Modification 3> In the above embodiment, the multiple second plates 80 are formed in a V-shape. However, this is not limiting, and the multiple second plates 280 may be formed in an arc-like shape, as shown in FIG. 6 . Specifically, the second plates 280a, 280b have arc-shaped main bodies 281a, 281b. The main bodies 281a, 281b are formed within a 180° range about the axis of the drive shaft 31 so as not to come into contact with the second sun gear 51 when the second plate 280 is attached to the second planetary carrier 54, and the inner circumferential surfaces 86a, 86b and the outer circumferential surfaces 87a, 87b are formed in corresponding shapes (specifically, concentric circles centered on the drive shaft 31). In other words, the inner circumferential surface 86a of the second plate 280a on the second sun gear 51 side and the outer circumferential surface 87a on the opposite side to the second sun gear 51 have curved portions 93a and 94a, respectively, and the curved portions 93a and 94a are formed concentrically (with the same shape) with each other. The inner circumferential surface 86b of the second plate 280b on the second sun gear 51 side and the outer circumferential surface 87b on the opposite side to the second sun gear 51 have curved portions 93b and 94b, respectively, and the curved portions 93b and 94b are formed concentrically (with the same shape) with each other. In this configuration, as in the second modification example 2, one end 282a of the second plate 280a and the other end 284b of the second plate 280b are butted against each other, and the other end 284a of the second plate 280a and one end 282b of the second plate 280b are butted against each other. The butting portions of the second plates 280a, 280b are each provided with a protrusion 288 and a recess 289 for accommodating the protrusion 288, which facilitates positioning of the second plates 280a, 280b relative to one another and improves the ease of assembly of the transmission 100. Note that the protrusion 288 and the recess 289 do not necessarily have to be provided, and the ends of the second plates 280a, 280b may overlap each other, as in the above embodiment. When the ends of the second plates 280 overlap each other, fastening holes 55 are formed at both ends of the second plate 280, and the angle between the centers of the fastening holes 55, centered on the axis of the drive shaft 31, is 180° when the second plate 280 is attached to the second planetary carrier 54.Even with this configuration, it is possible to reduce scrap material, and the second plates 280 are less likely to tilt, improving the durability of the second plates 280.

[0043] As shown in Fig. 6, the second plates 280a, 280b are preferably formed so that the inner diameter D1 is greater than twice the radial width D2. In this configuration, as shown in Fig. 7, when multiple plates 280 are punched out by press molding, the plate 280 can be formed so that the ends 282, 284 of the other two plates 280 fit into the space C inside the plate 280, allowing the space C to be used to form the other second plates 280. Therefore, compared to when a single annular second plate 580 is provided as shown in Fig. 8, the spaces that become waste material, such as the hollow portion A of the second plate 580 and the space B between the second plates 580, can be made smaller, thereby reducing waste material.

[0044] <Modification 4> In the above embodiment, the multiple second plates 80 are formed in a V-shape. However, this is not limiting, and the multiple second plates 380 may each be formed in a strip shape, as shown in FIG. The second plates 380a, 380b are formed with a uniform width, and the inner circumferential surfaces 86a, 86b on the second sun gear 51 side and the outer circumferential surfaces 87a, 87b on the side opposite the second sun gear 51 are formed in corresponding shapes (specifically, parallel to each other). In other words, the inner circumferential surface 86a on the second sun gear 51 side and the outer circumferential surface 87a on the side opposite the second sun gear 51 have linear portions 91a, 92a, respectively, and the linear portions 91a, 92a are formed parallel to each other (in the same shape). The second plate 380b has an inner circumferential surface 86b on the second sun gear 51 side and an outer circumferential surface 87b on the opposite side to the second sun gear 51, each having straight line portions 91b and 92b, and the straight line portions 91b and 92b are formed parallel to each other (with the same shape). In this modification, the entire inner circumferential surface 86a and the entire outer circumferential surface 87a of the second plate 380a are the straight line portions 91a and 92a, respectively, and the entire inner circumferential surface 86b and the outer circumferential surface 87b of the second plate 380b are the straight line portions 91b and 92b, respectively. In this case, the multiple second plates 380a, 380b are each provided between the second planetary gears 53 adjacent to each other in the circumferential direction. Specifically, the second plate 380a is provided between the second planetary gears 53a and 53b, and the second plate 380b is provided between the second planetary gears 53c and 53d. In this way, the plurality of second plates 380 do not necessarily have to be provided continuously so as to surround the second sun gear 51 .

[0045] Additionally, as shown in FIG. 10, second plates 380c and 380d may be provided, with the second plates 380a-380d overlapping each other. Specifically, the second plate 380c is provided between the second planetary gears 53b, and the second plate 380d is provided between the second planetary gears 53a and 53d. As in the above embodiment, a step may be formed on at least one end of each of the second plates 380a-380d, with the respective ends overlapping each other. In this configuration, the second plates 380 adjacent to each other in the circumferential direction are provided contiguously. Even with this configuration, waste material can be reduced.

[0046] <Modification 5> In the above embodiment, four second planetary gears 53 are provided, and two second plates 80 are provided to prevent two or more (three) second planetary gears 53 from coming off. However, the number of second planetary gears 53 and second plates 80 is not limited to the above. For example, as shown in FIG. 11 , three second planetary gears 53 may be provided, and three second plates 480 may be provided to prevent two second planetary gears 53 from coming off. Each of the multiple second plates 480 has an arc-shaped main body 481, and the inner circumferential surface 86 and the outer circumferential surface 87 are formed in corresponding shapes (specifically, the same radius of curvature). In other words, the inner circumferential surface 86 on the second sun gear 51 side and the outer circumferential surface 87 on the opposite side to the second sun gear 51 of the second plate 480 each have curved portions 93, 94, which are formed along each other (in the same shape). Note that the curved portions 93, 94 may or may not be perfectly circular. When the second plate 480 is attached to the second planetary carrier 54, the main body portion 481 is formed within a 120° range around the axis of the drive shaft 31. Specifically, fastening holes 55 are formed at both ends of the second plate 480, and when the second plate 480 is attached to the second planetary carrier 54, the angle between the centers of the fastening holes 55 and the axis of the drive shaft 31 is 120°. In this manner, when the multiple second plates are each formed in an arc shape, the length of the arc-shaped main body portion corresponds to the distance between circumferentially adjacent second planetary carriers 54. In this configuration, similar to the above embodiment, the ends of circumferentially adjacent second plates 480 (ends 482 and 484 on which the step portion 483 is formed) are arranged to overlap each other. Even with this configuration, multiple second plates 480 can be formed side by side with their inner circumferential surfaces 86 and outer circumferential surfaces 87 in contact with each other, as in FIG. 4, thereby reducing waste material. Furthermore, the second plates 480 are less likely to tilt, and the durability of the second plates 480 is improved.

[0047] <Modification 6> In the above embodiment, the inner shape (inner circumferential surface 86) and the outer shape (outer circumferential surface 87) of each of the multiple second plates 80 are formed to have partially corresponding shapes. This is not a limitation, and each of the multiple second plates 80 may be formed to have the entire inner shape and the entire outer shape corresponding to each other. Furthermore, it is not essential that the inner shape and the outer shape of each of the multiple second plates 80 be formed to have partially corresponding shapes.

[0048] <Seventh Modification> In the above embodiment, the plurality of second plates 80 are fixed to the second planetary carrier 54 by the second screw members 56. However, the present invention is not limited to this, and the plurality of second plates 80 may be fixed to the second planetary carrier 54 by, for example, a snap ring. In this configuration, a portion of the second planetary carrier 54 is formed to pass through the fastening hole 55, and the snap ring holds the plurality of second plates 80 so that they do not fall off the second planetary carrier 54.

[0049] The configuration, operation, and effects of the embodiment of the present invention will be described below.

[0050] The transmission 100 includes a drive shaft 31 as a shaft to which the output rotation of a hydraulic motor 20 as a drive source is transmitted, a planetary gear mechanism 40 connected to the drive shaft 31 and changing the speed of the output rotation of the hydraulic motor 20, and a cylindrical rotating housing 15 that houses the planetary gear mechanism 40 and rotates by receiving the changed output rotation, and the planetary gear mechanism 40 includes a second sun gear 51 as a sun gear to which the power of the hydraulic motor 20 is transmitted via the drive shaft 31, an inner gear 42 formed on the inner peripheral surface of the rotating housing 15, and a third sun gear 51 as a plurality of annular planetary gears having hollow portions and meshing with both the second sun gear 51 and the inner gear 42. The gearbox has two planetary gears (53) and a second planetary carrier (54) as a plurality of support parts that are inserted into the hollow parts of the second planetary gears (53) and support the second planetary gears (53), and the second planetary carrier (54) is provided with second plates (80, 180, 280, 380, 480) that cover at least a part of the second planetary gears (53) and are fixed to the second planetary carrier (54) to prevent the second planetary gears (53) from coming off the second planetary carrier (54), and the second plates (80, 180, 280, 380, 480) consist of a plurality of second plates, each fixed across two or more second planetary carriers (54).

[0051] In this configuration, the second planetary carrier 54 is provided with a plurality of second plates 80, 180, 280, 380, and 480, which prevent the planetary gears from coming loose. This allows the second plates 80, 180, 280, 380, and 480 to be smaller, and reduces the amount of scrap material discarded when forming the second plates 80, 180, 280, 380, and 480. This reduces the manufacturing cost of the transmission 100.

[0052] In addition, in the transmission 100, the inner shape (inner peripheral surface 86) on the second sun gear 51 side and the outer shape (outer peripheral surface 87) on the opposite side to the second sun gear 51 of the multiple second plates 80, 180, 380, 480 each have straight sections 91, 92 or curved sections 93, 94, and at least a portion of the straight sections 91, 92 or the curved sections 93, 94 are formed into corresponding shapes.

[0053] In this configuration, when the plurality of second plates 80, 180, 380, 480 are punched out by press molding, the plurality of second plates 80, 180, 380, 480 can be formed side by side, and therefore waste material can be reduced.

[0054] In addition, in the transmission 100, when each of the multiple second plates 280 is attached to the second planetary carrier 54, it is formed in an arc shape with a range of 180° centered on the axis of the drive shaft 31 so as not to come into contact with the second sun gear 51, and the inner diameter D1 is greater than twice the radial width D2.

[0055] In this configuration, when multiple second plates 280 are punched out by press molding, the ends 282, 284 of two other second plates 280 can be placed into the space C inside the second plate 280 to form the second plate 280, thereby reducing waste material.

[0056] Furthermore, in transmission 100, each of the plurality of plates 380 is formed in a strip shape.

[0057] In this configuration, when the plurality of second plates 380 are punched out by press molding, the plurality of second plates 380 can be formed side by side, and therefore scrap material can be reduced.

[0058] Furthermore, in transmission 100, the plurality of second plates 80, 180, 280, 380, 480 are provided continuously so as to surround second sun gear 51 when viewed in the axial direction of drive shaft 31.

[0059] In this configuration, the second plates 80, 180, 280, 380, and 480 are less likely to tilt, and the durability of the second plates 80, 180, 280, 380, and 480 is improved.

[0060] In addition, in the transmission 100, the multiple second plates 80, 480 each have a step 83, 483 formed in the plate thickness direction at at least one end 82, 482, and the other end 84, 484 enters the space between the step 83, 483 and the second planetary carrier 54, so that the respective end portions 82, 84, 482, 484 overlap each other.

[0061] In this configuration, even if the ends 82, 84, 482, 484 of the second plates 80, 480 are overlapped, the stepped portions 83, 483 make it possible to flatten the side facing the second planetary gear 53. This prevents the second plates 80, 480 and the second planetary gear 53 from coming into partial contact with each other, improving the durability of the transmission 100.

[0062] Furthermore, in the transmission 100, the multiple second plates 180, 280 are provided with their respective ends 182, 184, 282, 284 abutting against each other.

[0063] In this configuration, the second plates 180, 280 are less likely to tilt, and the durability of the second plates 180, 280 is improved.

[0064] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0065] This application claims priority based on Japanese Patent Application No. 2023-102358, filed with the Japan Patent Office on June 22, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. A transmission comprising: a shaft to which output rotation of a drive source is transmitted; a planetary gear mechanism connected to the shaft and changing the speed of the output rotation of the drive source; and a cylindrical rotating housing that houses the planetary gear mechanism and rotates by the changed output rotation, wherein the planetary gear mechanism has: a sun gear to which power of the drive source is transmitted via the shaft; an inner gear formed on the inner surface of the rotating housing; a plurality of annular planetary gears having hollow portions and meshing with both the sun gear and the inner gear; and a plurality of support parts that are inserted into the hollow portions of the plurality of planetary gears and support the planetary gears, wherein the support parts are provided with plates that cover at least a portion of the planetary gears and are fixed to the support parts to prevent the planetary gears from coming off the support parts, and the transmission comprises a plurality of plates, each of which is fixed across two or more of the support parts.

2. A transmission as claimed in claim 1, wherein the inner shape of the plurality of plates on the sun gear side and the outer shape on the opposite side to the sun gear each have straight or curved sections, and at least a portion of the straight sections or the curved sections are formed into corresponding shapes.

3. A transmission as claimed in claim 1, wherein the plurality of plates, when attached to the respective supports, are formed in an arc shape of a range of 180° about the axis of the shaft so as not to come into contact with the sun gear, and the inner diameter is greater than twice the radial width.

4. A transmission according to claim 1, wherein each of said plurality of plates is formed in a rectangular shape.

5. A transmission according to any one of claims 1 to 4, wherein the plurality of plates are arranged contiguously with one another so as to surround the sun gear when viewed in the axial direction of the shaft.

6. A transmission as claimed in claim 5, wherein each of the plurality of plates has a step formed in the thickness direction at least on one end thereof, and the other end fits into the space between the step and the support portion, so that the ends overlap each other.

7. A transmission according to claim 5, wherein the plurality of plates are provided with their respective ends butted against each other.

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