Planetary gear transmission

Abstract

To provide a planetary gear type continuously variable transmission that reduces the installation space required for shifting gears and improves the gear range. [Solution] The system includes a speed control mechanism 3 that changes the rotational speed of the input shaft 2, and a planetary gear mechanism 5 that changes the output rotational speed according to the difference between the rotational speed adjusted by the speed control mechanism 3 and the rotational speed of the input shaft 2. The rotational motion of the internal gear 53 constituting the planetary gear mechanism 5 can be adjusted via the input gear 30, speed control gear 31, speed control input gear 32, and bevel gear 33 constituting the speed control mechanism 3, thereby making it possible to adjust the rotational motion of the output shaft 4.

Description

Technical Field

[0001] This invention relates to an epicyclic gear type transmission using bevel gears.

Background Art

[0002] Conventionally, a transmission changes speed by changing the rotational radius of each engaging gear, for example, as shown in FIG. 8. The transmission in FIG. 8 has two friction wheels 70 and 71 formed in a disc shape having rotation axes orthogonal to each other. In this transmission, power can be transmitted from one friction wheel 70 to the other friction wheel 71 by bringing the peripheral portion 71a of the other friction wheel 71 into contact with the rolling surface 70a of one friction wheel 70. The speed is changed by changing the rotation ratio of the other friction wheel 71 with respect to the friction wheel 70 according to the position in the radial direction of the rolling surface 70a of one friction wheel 70 where the peripheral portion 71a of the other friction wheel 71 is brought into contact. In such a transmission, the contact pressure between the friction wheels 70 and 71 on the driving side and the driven side is set high so that power can be reliably transmitted from one friction wheel 70 on the driving side to the other friction wheel 71 on the driven side.

[0003] However, when the contact pressure between the two friction wheels 70 and 71 is set high, there is a problem that the rolling surface 70a and the peripheral portion 71a wear due to contact with each other, significantly reducing the life of the device.

[0004] As means for solving such problems, the techniques described in Patent Document 1 and Patent Document 2 are disclosed. In Patent Document 1, an input-side rotor provided movably along a horizontal input shaft and biased forward by a biasing member provided on the input shaft, and an output shaft provided vertically in a direction orthogonal to the input shaft. An output rotor provided movably along the output shaft and biased upward by a biasing member provided on the output shaft, and the rotation radius can be arbitrarily and continuously adjusted according to the fitting position between the input rotor and the output rotor, enabling stepless speed change. By configuring in this way, speed change is possible according to the contact position between the output rotor and the input rotor.

[0005] Furthermore, Patent Document 2 describes a continuously variable transmission that comprises a conical triple gear, an inverted conical triple gear which is the same as the conical triple gear but inverted vertically, and a relay gear which transmits rotational power from one triple gear to the other. The relay gear is configured to be movable in an oblique vertical direction along the inclined surface of the tooth profiles of the conical triple gear and the inverted conical triple gear, thereby enabling stepless speed control. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2001-153190 [Patent Document 2] Japanese Patent Publication No. 2017-190864 [Disclosure of the Invention] [Problems that the invention aims to solve]

[0007] However, while the above-mentioned Patent Documents 1 and 2 can improve transmission efficiency, their structure becomes complex and they do not contribute to saving space for the entire transmission.

[0008] This invention was made in view of the above-mentioned problems, and aims to provide a planetary gear type transmission that reduces the installation space required for shifting speeds and improves the shifting range. [Means for solving the problem]

[0009] The planetary gear type transmission according to the present invention comprises a transmission mechanism for changing the rotational speed of an input shaft, and a planetary mechanism for changing the output rotational speed according to the difference between the rotational speed adjusted by the transmission mechanism and the rotational speed of the input shaft, wherein the transmission mechanism comprises an input gear rotatably connected to the input shaft, a transmission gear meshing with the input gear, a power transmission shaft connected to the transmission gear and extending in a direction along the axis of the transmission gear, a constant velocity joint provided at the tip of the power transmission shaft, a transmission input gear rotatably connected to the constant velocity joint, and a bevel gear meshing with the transmission input gear, wherein the planetary mechanism is connected to one end of the input shaft The present invention comprises a sun gear connected to one end of the input shaft so as to be synchronously rotatable with the input shaft, an internal gear provided around the sun gear so as to be rotatable about the axis of the sun gear, a planetary gear provided between the sun gear and the internal gear and meshing with the sun gear and the internal gear, and a planetary carrier configured to be rotatable about the axis of the sun gear while rotatably supporting the planetary gear, wherein the base end of the planetary carrier is connected to the bevel gear so as to be rotatable together, and the rotational speed of the output shaft connected to the internal gear can be adjusted according to the difference in rotational speed between the sun gear connected to the tip of the input shaft and the planetary carrier.

[0010] Another aspect of the present invention relates to a planetary gear type transmission, characterized in that the meshing position between the transmission input gear and the bevel gear is displaceable around the constant velocity joint.

[0011] Another aspect of the present invention relates to a planetary gear type transmission, characterized in that the transmission input gear has a gear cog on its outer circumferential surface, and the width of the gear cog is configured to gradually narrow from one end to the other. [Effects of the Invention]

[0012] This invention comprises a speed control mechanism for changing the rotational speed of an input shaft, and a planetary gear mechanism for changing the output rotational speed according to the difference between the rotational speed adjusted by the speed control mechanism and the rotational speed of the input shaft. The speed control mechanism comprises an input gear rotatably connected to the input shaft, a speed control gear meshing with the input gear, a power transmission shaft connected to the speed control gear and extending in a direction along the axis of the speed control gear, a constant velocity joint provided at the tip of the power transmission shaft, a speed control input gear rotatably connected to the constant velocity joint, and a bevel gear meshing with the speed control input gear. The planetary gear mechanism is connected to one end of the input shaft and rotatably connected to the input shaft. The transmission comprises a sun gear connected to one end of the input shaft, an internal gear rotatably mounted around the sun gear's axis, planetary gears mounted between the sun gear and the internal gear and meshing with the sun gear and the internal gear, and a planetary carrier configured to rotatably support the planetary gears while being rotatable around the axis of the sun gear. The base end of the planetary carrier is connected to the bevel gear so as to be rotatable together, and the rotational speed of the output shaft connected to the internal gear can be adjusted according to the difference in rotational speed between the sun gear and the planetary carrier connected to the tip of the input shaft. This configuration allows for a compact overall transmission, reducing the installation space required for the transmission. Furthermore, because the sun gear, planetary gears, internal gear, and planetary carrier constituting the planetary mechanism are rotated without being fixed, the rotational speed of the output shaft can be adjusted simply by adjusting the rotational speed of the planetary carrier by the transmission mechanism, thereby widening the overall transmission range.

[0013] Furthermore, this planetary gear type transmission allows for a change in the transmission speed from the input gear to the bevel gear by making the meshing position between the input gear and the bevel gear freely displaceable around the constant velocity joint, thereby enabling a more compact overall device.

[0014] In addition, in this planetary gear type transmission, the transmission input gear has gear teeth on its outer peripheral surface, and the width of the gear teeth is configured to gradually decrease from one end to the other end, so that the rotational speed transmitted from the input shaft to the output shaft can be changed with a simple structure. Further, since the transmission can be realized with a simple structure that only rotates the gear teeth of the transmission input gear, the entire device can be made compact.

Brief Description of the Drawings

[0015] [Figure 1] It is a schematic diagram showing a planetary transmission according to an embodiment of the present invention. [Figure 2] It is a side view showing a transmission input gear according to an embodiment of the present invention. [Figure 3] It is a rear side perspective view showing a transmission input gear according to an embodiment of the present invention. [Figure 4] It is a front side perspective view showing a transmission input gear according to an embodiment of the present invention. [Figure 5] It is a front view showing a hub gear according to an embodiment of the present invention. [Figure 6] It is a side view showing a planetary mechanism part according to an embodiment of the present invention. [Figure 7] It is a side view showing the power transmission of a planetary mechanism part according to an embodiment of the present invention. [Figure 8] It is a schematic diagram showing a conventional transmission.

Embodiments for Carrying Out the Invention

[0016] The gist of this invention is to provide a planetary gear type transmission that is compact and has a wide transmission range by devising a power transmission mechanism to the output shaft with a transmission mechanism part having an input gear, a transmission gear, a transmission input gear, and a hub gear, and a planetary mechanism part having a sun gear, a planetary gear, an internal gear, and a planetary carrier.

[0017] The configuration of the planetary gear type transmission 1 according to this embodiment will be described with reference to FIGS. 1 to 7. FIG. 1 is a diagram showing the schematic structure of the planetary gear type transmission 1 according to this embodiment. FIGS. 2 to 5 are drawings showing the transmission input gear 32 and the bevel gear 33 that constitute the transmission mechanism portion 3 of the planetary gear type transmission 1. FIG. 6 is a diagram showing the positional relationship of the sun gear 50, the planetary gears 51, the planetary carrier 52, and the internal gear 53 that constitute the planetary mechanism portion 5 of the planetary gear type transmission 1. FIG. 7 is a diagram showing the power transmission of each gear that constitutes the planetary mechanism portion 5 of the planetary gear type transmission 1. In describing this embodiment, the left-right direction in FIG. 1 is taken as the front-rear direction, the up-down direction is taken as the left-right direction, the input shaft 2 side is taken as the rear side, and the output shaft 4 side is taken as the front side. Also, in this embodiment, an example is shown in which the rotational power is transmitted from the input shaft 2 side provided on the right side of FIG. 1 to the output shaft 4 side provided on the left side. However, the relationship between the input shaft 2 and the output shaft 4 is not limited to this, and it can also be configured such that the left side of FIG. 1 is the input shaft 2 and the right side of FIG. 1 is the output shaft 4.

[0018] The planetary gear type transmission 1 according to this embodiment has a transmission mechanism portion 3 that variably adjusts the rotational power transmitted through the input shaft 2, and a planetary mechanism portion 5 that variably transmits the rotational power output from the output shaft 4 after receiving the variable adjustment by the transmission mechanism portion 3.

[0019] The transmission mechanism portion 3 has an input shaft 2 that transmits rotational power, an input gear 30 connected to an intermediate portion of the input shaft 2, a transmission gear 31 meshing with the input gear 30, a transmission input gear 32 connected to the transmission gear � via a power transmission shaft 34, and a bevel gear 33 connected to the transmission input gear 32.

[0020] The input shaft 2 is formed in a substantially cylindrical shape extending linearly, with its base end connected to a motor and its tip end connected to the sun gear 50 of the planetary mechanism portion 5 described later. The input shaft 2 engages and fixes the input gear 30 between the motor and the sun gear 50, and is configured such that the input gear 30 and the sun gear 50 rotate in synchronization with the rotational operation of the input shaft 2. Note that the motor described above refers to a device that transmits power to rotate the input shaft 2 around the axis C1 of the input shaft 2, and is not limited to a motor such as an engine.

[0021] The input gear 30 is a bevel gear formed in the shape of a flattened frustoconical cone, and a speed-shifting gear 31 meshes with a gear cog provided on its circumferential surface. The outer diameter of the input gear 30 is formed to be approximately the same as that of the internal gear 53, which constitutes the planetary mechanism 5 described later, when viewed from the front. The outer diameter of the input gear 30 is not limited to the size described in this embodiment, and may be formed to be smaller or larger than that of the internal gear 53. However, in order to avoid interference between the speed-shifting gear 31, which meshes with the gear cog, and the bevel gear 33, when viewed from the rear, the input gear 30 is formed to be larger in diameter than that of the bevel gear 33, as described later.

[0022] As shown in Figure 1, the variable speed gear 31 is a bevel gear formed in the shape of a frustoconical pyramid, and is formed to have a smaller diameter than the input gear 30. The variable speed gear 31 meshes with the input gear 30 in such a manner that its axis C3 is inclined at an angle α with respect to the axis C2 of the input gear 30.

[0023] The variable speed gear 31 has a straight rod-shaped power transmission shaft 34 connected to its approximate center. The power transmission shaft 34 extends in a direction along the axis C3 of the variable speed gear 31, with its base end connected to the variable speed gear 31, and a constant velocity joint 35 connected to its tip.

[0024] The constant velocity joint 35 is made of a ball joint and engages with the variable speed input gear 32. This allows for smooth transmission of rotational power from the variable speed gear 31 to the variable speed input gear 32. In other words, by using the constant velocity joint 35 for power transmission, the variable speed gear 31 and the variable speed input gear 32 are connected in a manner in which the axis C4 of the variable speed input gear 32 is inclined relative to the axis C3 of the variable speed gear 31, but rotational power loss is reduced and the rotational motion of the variable speed gear 31 can be transmitted without reducing rotational efficiency. In this embodiment, the constant velocity joint 35 is made of a constant velocity ball joint, but it can be made of any type as long as there is little power loss in the process of transmitting the rotational power of the power transmission shaft 34 to the variable speed input gear 32.

[0025] As shown in Figures 2 to 4, the speed change input gear 32 has a gear body 32a formed in a substantially cylindrical shape and a gear cog 32b provided on the outer circumferential surface of the gear body 32a along the longitudinal direction of the gear body 32a. The gear body 32a is formed in a substantially cup shape, with a hollow section extending from the center of the end on the speed change gear 31 side to the center of the gear body 32a, and the constant velocity joint 35 is housed in this hollow section. In other words, the gear body 32a is tiltable with respect to the axis C3 around the constant velocity joint 35. The axes C2 and C3 are located on the same plane, and when axis C3 is extended, it intersects with axis C2 at a single point. In other words, axes C2 and C3 are set at an angle α. Angle α is set to an angle at which the speed change input gear 32 and the bevel gear 33 can mesh, and in this embodiment, it is set to 45 degrees. However, angle α is not limited to 45 degrees; it can be set to any angle that allows the speed input gear 32 and the bevel gear 33 to mesh.

[0026] Furthermore, the angle β between axis C3 and axis C4 can be arbitrarily changed within the range of 0 to 20 degrees. The rotational speed of the bevel gear 33 meshed with the speed-shifting input gear 32 is such that when the angle β is 0 degrees, i.e., when axis C3 and axis C4 coincide, the bevel gear 33 rotates at high speed, and the rotational speed of the bevel gear 33 gradually decreases as the angle increases.

[0027] Multiple gear cogs 32b are provided on the outer circumferential surface of the gear body 32a at regular intervals in the circumferential direction of the gear body 32a. The gear cogs 32b are configured such that their width gradually narrows from one end (the side of the variable speed gear 31) to the other end (the side of the tip of the variable speed gear 31) in the longitudinal direction of the gear body 32a. Furthermore, as shown in Figure 2, the gear cogs 32b are configured such that their height gradually increases from the outer circumferential surface of the gear body 32a towards the radially outward direction of the gear body 32a, from the narrow end to the wide end. By forming the gear cogs 32b in this way, recesses 32c are formed on the outer circumferential surface of the gear body 32a between adjacent gear cogs 32b. The recesses 32c are formed in the shape of an inverted gear cog 32b. In other words, the recesses 32c are formed to gradually widen or gradually narrow from one end to the other, similar to the gear cogs 32b. A bevel gear 33 meshes with the speed input gear 32 formed in this manner.

[0028] As shown in Figure 5, the bevel gear 33 has a gear body 33a formed in the shape of a frustoconical pyramid and a gear cog 33b provided on the outer circumferential surface of the gear body 33a. The gear body 33a has a hole 33d formed through the central part along the front-rear direction. In a cross-sectional view of the bevel gear 33, the gear cog 33b is formed in the shape of a convex arc that is convex outward in the radial direction. Furthermore, the gear cog 33b is formed with a substantially constant width from one end on the central side to the other end on the peripheral side. In other words, the gear cog 33b is configured such that the distance between adjacent gear cogs 33b gradually increases from the central part 33c to the peripheral side 33e.

[0029] In this way, the gear cogs 33b provided on the outer circumferential surface of the gear body 33a of the bevel gear 33 are formed with a substantially constant width, and the spacing between adjacent gear cogs 33b gradually widens from the central part 33c to the peripheral part 33e, allowing the meshing position between the speed input gear 32 and the bevel gear 33 to be adjusted arbitrarily. In other words, by forming the spacing between adjacent gear cogs 33b of the bevel gear 33 and the width of the gear cogs 32b of the speed input gear 32 to be substantially the same, or by forming the spacing between adjacent gear cogs 33b to be slightly wider than the width of the gear cogs 32b, the speed input gear 32 and the bevel gear 33 can be meshed at any position from the central part 33c to the peripheral part 33e. In other words, the gear ratio between the speed input gear 32 and the bevel gear 33 can be changed arbitrarily.

[0030] For example, when rotating the bevel gear 33 at high speed, the gear cog 32b on the front end of the speed input gear 32 meshes with the gear cog 33b on the central part 33c of the bevel gear 33. When rotating the bevel gear 33 at low speed, the gear cog 32b on the rear end of the speed input gear 32 meshes with the gear cog 33b on the peripheral part 33e of the bevel gear 33. In this way, the gear ratio can be arbitrarily changed between the speed input gear 32 and the bevel gear 33. Furthermore, by forming the spacing between adjacent gear cogs 33b of the bevel gear 33 to be approximately the same as, or slightly wider than, the width of the gear cog 32b of the speed input gear 32, the speed input gear 32 and the bevel gear 33 can mesh reliably, and rotational power can be reliably transmitted from the speed input gear 32 to the bevel gear 33. Furthermore, the method for changing the meshing position of the speed-shifting input gear 32 with respect to the bevel gear 33 is not particularly limited and can be changed by any method.

[0031] Furthermore, the input shaft 2 and the planetary carrier 52 are inserted through a hole 33d formed through the center of the bevel gear 33 from front to back. The gear body 33a and the planetary carrier 52 are connected in a spline manner, allowing the planetary carrier 52 to rotate in conjunction with the rotational movement of the bevel gear 33. In other words, the planetary carrier 52 can rotate in sync with the rotational movement of the bevel gear 33. To put it another way, the bevel gear 33 and the planetary carrier 52 rotate at the same angular velocity. The input shaft 2 does not interfere with either the planetary carrier 52 or the bevel gear 33, and therefore rotates independently of the planetary carrier 52. In other words, the input shaft 2 rotates without interference from the bevel gear 33 or the planetary carrier 52.

[0032] The planetary gear mechanism 5 is composed of a so-called planetary gear mechanism and includes a sun gear 50 connected to the tip of the input shaft 2 and located in the center of the planetary gear mechanism 5, a plurality of planetary gears 51 provided around the sun gear 50, a planetary carrier 52 that synchronously rotates the plurality of planetary gears 51 around the axis of the sun gear 50, an internal gear 53 provided radially outside the planetary gears 51 so as to be rotatable around the sun gear 50 around the axis of the sun gear 50 and having a meshing surface with the planetary gears 51, and an output shaft 4 integrally connected to the internal gear 53.

[0033] The sun gear 50 is connected to the tip of the input shaft 2 and has a gear cog 50a formed in a beveled tooth shape on its outer circumference. The sun gear 50 and the input shaft 2 share the same axis (axis C1, axis C2). The sun gear 50 and the input shaft 2 are fitted together by a spline, and the input shaft 2 and the sun gear 50 are configured to rotate synchronously. In this embodiment, the gear cog 50a of the sun gear 50 is shown as a beveled tooth shape, but the shape of the gear cog 50a is not limited to a beveled tooth shape and may be formed in a spur tooth shape as long as the rotational motion of the sun gear 50 is transmitted to the planetary gear 51.

[0034] The planetary carrier 52 has a rotating shaft body portion 52a that engages with the bevel gear 33, a rotation transmission arm portion 52b that branches out radially outward from the tip of the rotating shaft body portion 52a in a bifurcated manner, and a rotation support portion 52c that extends from the rotation transmission arm portion 52b in the direction of the output shaft 4, substantially parallel to the input shaft 2.

[0035] The rotating shaft body 52a is a hollow cylindrical body that extends substantially linearly along the input shaft 2. Its base end is fitted into the hole 33d of the bevel gear 33 by a spline, and its tip is connected to the rotation transmission arm 52b. The input shaft 2 is inserted through the hollow part of the rotating shaft body 52a. Ball bearings are placed between the rotating shaft body 52a and the input shaft 2 so that they do not come into contact. This allows the planetary carrier 52 and the sun gear 50 to rotate independently.

[0036] The rotation transmission arm portion 52b extends radially outward from the tip of the rotating shaft body portion 52a. The rotation transmission arm portion 52b is connected to the rotation support portion 52c near its tip.

[0037] The rotation support portion 52c bends from the tip of the rotation transmission arm portion 52b in the direction of the output shaft 4 and extends substantially parallel to the input shaft 2 or the output shaft 4. The rotation support portion 52c is formed in a solid cylindrical shape and rotatably supports the planetary gear 51 near its tip.

[0038] The planetary gear 51 is a cylindrical body with a hollow interior and has a gear cog 51a formed in an oblique tooth shape on its outer circumference. The planetary gear 51 is pivotally supported by the rotation support portion 52c of the planetary carrier 52, and the gear cog 51a on its circumference meshes with the sun gear 50 and the internal gear 53. In other words, the inner portion (axis C1 side) of the planetary gear 51 meshes with the sun gear 50 in the rotational motion of the planetary carrier 52, and the outer portion (radially outside the axis C1) meshes with the internal gear 53 in the rotational motion. To put it another way, the planetary gear 51 is configured to rotate around axis C1 while meshing with both the sun gear 50 and the internal gear 53.

[0039] As shown in Figure 1, the internal gear 53 has a gear body 53a connected to the output shaft 4 and a gear portion 53b that meshes with the planetary gear 51.

[0040] As shown in Figures 1 and 6, the gear body 53a is formed as a hollow interior with a closed end and a bottom, and is open in the direction facing the input shaft 2. The gear body 53a has a bottom side wall 53c and a side wall 53d that extends from the periphery of the bottom side wall 53c toward the input shaft 2 along the axis C1 of the input shaft 2. The bottom side wall 53c is formed in a substantially disc shape with the axis C1 direction as the thickness direction, and the output shaft 4 is connected to its center. In other words, the gear body 53a and the output shaft 4 are integrally formed, and the output shaft 4 rotates in synchronization with the rotational movement of the internal gear 53. Furthermore, the side wall 53d extends its rear end (the end on the input shaft 2 side) to the rear end of the sun gear 50. In other words, the rear end of the side wall 53d and the rear end of the sun gear 50 are located on substantially the same vertical plane in a plan view, as shown in Figure 1. Furthermore, the output shaft 4 is connected to the front center of the bottom side wall portion 53c. In other words, the rotational motion of the gear body portion 53a is transmitted to the output shaft 4, and the gear body portion 53a and the output shaft 4 are configured to rotate together as a single unit.

[0041] The inner surface of the side wall portion 53d has a gear portion 53b. As shown in Figure 1, the gear portion 53b is formed to have a front-to-back width approximately the same as the front-to-back width of the sun gear 50, and has a gear cog 53e formed in an oblique tooth shape on the surface that meshes with the planet gear 51. The gear portion 53b meshes with the planet gear 51 via the cog formed in an oblique tooth shape.

[0042] The planetary gear mechanism 5 is formed as described above and controls the rotational movement of the internal gear 53, which rotates integrally with the output shaft 4, in response to two input rotational movements: a sun gear 50 that rotates in conjunction with the rotational movement of the input shaft 2, and planetary gears 51 that rotate around the sun gear 50 with its axis C2 as the center, in the same direction as the rotation of the sun gear 50, in conjunction with the rotational movement of the planetary carrier 52.

[0043] In other words, the rotational speed of the internal gear 53 can be changed according to the difference in rotational speed of the planetary gears 51 corresponding to the rotational motion of the sun gear 50 and the planetary carrier 52 around axis C2. To put it another way, the rotational speed (angular velocity) of the output shaft 4 can be adjusted according to the difference between the rotational motion of the planetary gears 51 caused by the rotational motion of the sun gear 50 and the rotational motion of the planetary gears 51 caused by the rotational motion of the planetary carrier 52 around axis C2. In this way, by configuring the rotational speed of the planetary gears 51 constituting the planetary mechanism 5 to be adjustable with a single input shaft 2, the entire device can be made compact, and the rotational speed of the planetary carrier 52 can be changed by passing the power branched from the input shaft 2 through the speed change mechanism 3, thereby expanding the range of speed change of the output shaft 4.

[0044] <About operation> Next, the operation of the planetary gear type transmission 1 will be explained with reference to Figures 1 and 7.

[0045] The planetary gear type transmission 1 is configured such that the planetary motion of the planetary gears 51 is controlled by the transmission mechanism 3, and that none of the gears constituting the planetary mechanism 5—the sun gear 50, the planetary gears 51, and the internal gear 53—are fixed, allowing them to rotate freely around the axis C2 of the sun gear 50. This configuration allows for a wider range of adjustment of the reduction ratio between the input shaft 2 and the output shaft 4. The control operation of this planetary gear type transmission 1, which changes the reduction ratio between the input shaft 2 and the output shaft 4, will be described in detail below.

[0046] First, when the input shaft 2 rotates, the input gear 30 and the sun gear 50 begin to rotate simultaneously. At this time, the input gear 30 and the sun gear 50 rotate at the same angular velocity as the input shaft 2. The rotational motion of the input gear 30 is then transmitted to the variable gear 31.

[0047] Next, the angular velocity of the variable speed gear 31 changes according to the gear ratio with respect to the input gear 30. In this embodiment, by forming the variable speed gear 31 with a smaller diameter than the input gear 30, the angular velocity of the variable speed gear 31 becomes faster than that of the input gear 30.

[0048] Subsequently, the rotational motion of the variable speed gear 31 is transmitted to the variable speed input gear 32 via the power transmission shaft 34 and the constant velocity joint 35. The variable speed gear 31, the variable speed input gear 32, the power transmission shaft 34, and the constant velocity joint 35 rotate at approximately the same angular velocity.

[0049] The rotational motion of the speed-shifting input gear 32 is transmitted to the bevel gear 33. In this process, the transmission of rotational power is varied according to the contact position between the gear cog 32b provided on the outer circumferential surface of the gear body 32a constituting the speed-shifting input gear 32 and the gear cog 33b of the gear body 33a constituting the bevel gear 33.

[0050] In this embodiment, a configuration in which the gear cog 32b on the tip side of the speed-shifting input gear 32, that is, the end side different from the end that connects to the constant velocity joint 35, contacts the gear cog 33b provided on the front side of the outer circumference of the bevel gear 33 results in high-speed rotation, while a configuration in which the gear cog 32b on the base end side, that is, the end side that connects to the constant velocity joint 35, contacts the gear cog 33b provided on the rear side of the outer circumference of the bevel gear 33 results in low-speed rotation. In other words, the smaller the angle β that the axis C4 of the speed-shifting input gear 32 makes with the axis C3 of the power transmission shaft 34, the faster the bevel gear 33 rotates, and the larger the angle β, the slower the bevel gear 33 rotates.

[0051] Here, the change in rotational power transmitted from the speed input gear 32 to the bevel gear 33 will be explained in detail using Figure 7.

[0052] First, let's describe the pattern in which the rotational power transmitted from the speed-shifting input gear 32 to the bevel gear 33 is at a low speed. When the rotational power of the speed-shifting input gear 32 is transmitted to the bevel gear 33 at a low speed, the rear end of the gear cog 32b constituting the speed-shifting input gear 32 is meshed with the circumferential surface of the rear end of the gear cog 33b of the bevel gear 33. As a result, the rotational radius of the gear cog 33b that meshes with the gear cog 32b increases, and the distance the bevel gear 33 rotates while the speed-shifting input gear 32 rotates once increases. Consequently, the rotational speed of the rotating shaft body 52a of the planetary carrier 52 connected to the bevel gear 33 can be reduced.

[0053] Next, we will describe a pattern in which rotational power is transmitted from the speed-shifting input gear 32 to the bevel gear 33 at high speed. When the rotational power of the speed-shifting input gear 32 is transmitted to the bevel gear 33 at high speed, the front end of the gear cog 32b constituting the speed-shifting input gear 32 is meshed with the circumferential surface of the front end of the gear cog 33b of the bevel gear 33. As a result, the rotational radius of the gear cog 33b that meshes with the gear cog 32b is reduced, and the distance the bevel gear 33 rotates while the speed-shifting input gear 32 rotates once is shortened. As a result, the rotational speed of the rotating shaft body portion 52a of the planetary carrier 52 connected to the bevel gear 33 can be increased.

[0054] The bevel gear 33 is spline-fitted to the rotating shaft body 52a of the planetary carrier 52, causing the planetary carrier 52 to rotate at the same angular velocity as the bevel gear 33.

[0055] As the planetary carrier 52 rotates, the planetary gear 51, pivotally supported by the rotation support part 52c provided at the tip of the planetary carrier 52, rotates around the sun gear 50 with its axis C2 at an angular velocity approximately the same as that of the planetary carrier 52.

[0056] Then, the rotational motion of the planetary gear 51 and the rotational motion of the internal gear 53 change according to the difference between the rotational motion of the sun gear 50 connected to the input shaft 2 and the rotational motion of the planetary carrier 52 connected to the bevel gear 33.

[0057] In detail, as shown in Figure 7, the angular velocity of the input shaft 2 when it rotates is denoted as angular velocity A, and the angular velocity of the planetary carrier 52 when it rotates around the sun gear 50 with axis C2 is denoted as angular velocity B. When the input shaft 2 rotates clockwise at angular velocity A, the sun gear 50 also rotates clockwise at angular velocity A, and the rotational motion of the sun gear 50 is transmitted to the planetary gear 51, causing the planetary gear 51 to rotate counterclockwise at angular velocity A. Then, the counterclockwise angular velocity A of the planetary gear 51 is transmitted to the internal gear 53. In other words, the rotational power of the input shaft 2 becomes rotational motion in the opposite direction to the input shaft 2, and becomes the rotational power that rotates the internal gear 53. To put it another way, the internal gear 53 rotates at the angular velocity A of the input shaft 2, and that rotational power is transmitted to the internal gear 53. In other words, the rotational power of the input shaft 2 becomes the rotational power that rotates the internal gear 53.

[0058] Furthermore, when the planetary carrier 52 rotates clockwise at an angular velocity B, the planetary gear 51 begins rotational motion around the sun gear 50 with respect to the axis C2, in a manner that meshes with the sun gear 50 and the internal gear 53. As a result, loads corresponding to the angular velocity B of the planetary carrier 52 are generated on the sun gear 50 and the internal gear 53, respectively. Specifically, when the planetary carrier 52 rotates clockwise, the planetary gear 51 generates a load on the sun gear 50 in a direction that causes it to rotate clockwise. Also, a load is generated on the internal gear 53 from the planetary carrier 52 in a direction that causes it to rotate clockwise. The internal gear 53 then rotates at an angular velocity corresponding to the difference between the angular velocity A of the sun gear 50 and the angular velocity B of the planetary carrier 52. In this case, if the angular velocity A of the sun gear 50 is greater than the angular velocity B of the planetary carrier 52, it rotates clockwise, and if the angular velocity A of the sun gear 50 is less than the angular velocity B of the planetary carrier 52, it rotates counterclockwise. In other words, the state in which the angular velocity B of the planetary carrier 52 is minimized corresponds to the state in which the angular velocity of the output shaft 4 is fastest, and the state in which the angular velocity B of the planetary carrier 52 is maximized corresponds to the state in which the angular velocity of the output shaft 4 is slowest.

[0059] Thus, in this embodiment, the planetary gear type transmission 1 has a configuration in which the sun gear 50, planetary carrier 52, and planetary gear 51 forming the planetary mechanism 5 are the input side of rotational power, and the internal gear 53 is the output side. This configuration allows the angular velocity of the internal gear 53 to be affected according to the difference between the angular velocities A and B of the sun gear 50 and the planetary carrier 52, and as a result, the angular velocity of the output shaft 4 which rotates integrally with the internal gear 53 can be affected.

[0060] In other words, the essential part of the planetary gear type transmission 1 in this embodiment is configured to adjust the rotational motion of the output shaft 4 by dividing the rotational motion of the input shaft 2, which is the starting point of rotational power, into a sun gear 50 and a planetary carrier 52, transmitting them to the planetary gear 51, and transmitting the rotational motion of the planetary carrier 52 to the internal gear 53.

[0061] Then, the internal gear 53 rotates in response to the rotational motion of the planetary gear 51, causing the output shaft 4 to rotate. The load transmitted from the planetary gear 51 to the internal gear 53 at this time is as shown in Figure 7. In other words, the internal gear 53 can change its rotational speed according to the difference between the rotational speed of the sun gear 50 and the rotational speed of the planetary carrier 52 that constitute the planetary gear 51.

[0062] Thus, in this embodiment, the gear ratio between the input shaft 2 and the output shaft 4 changes according to the difference between the angular velocity of the sun gear 50 and the angular velocity of the planetary carrier 52 that constitute the planetary mechanism 5. In particular, by adjusting the gear ratio between the input gear 30 connected to the input shaft 2 and the variable gear 31 meshed with the input gear 30, and the gear ratio between the variable input gear 32 and the bevel gear 33, the rotational speed that rotates the planetary carrier 52 can be changed, thereby adjusting the difference in rotational speed between the sun gear 50 and the planetary carrier 52 and expanding the gear ratio of the speed that rotates the output shaft 4.

[0063] Furthermore, in this embodiment, the transmission mechanism 3 is configured to be able to change speed using two gears: the gear ratio between the input gear 30 and the gear change gear 31, and the gear ratio between the gear change input gear 32 and the bevel gear 33. The configuration also allows for adjustment of the gear range in the planetary gear mechanism 5 by adjusting the gear change in the transmission mechanism 3. This provides a compact planetary gear type transmission 1 with an expanded range of adjustable gear changes. Additionally, by adjusting the gear ratio between the input gear 30 and the gear change gear 31, it is possible to transmit rotational power from the power source to the input shaft 2 while simultaneously stopping the rotational motion of the output shaft 4. In other words, by adjusting the gear ratio between the input gear 30 and the gear change gear 31, and between the gear change input gear 32 and the bevel gear 33, the rotational motion of the internal gear 53 can be prevented, thereby stopping the rotation of the output shaft 4. In other words, the rotational motion of the output shaft 4 can be stopped without disengaging the power transmission components using a clutch or the like, and the rotational motion of the output shaft 4 can be changed while including a state of no rotation (angular velocity of 0). This allows for a reduction in the number of parts, making the entire device compact while expanding the range of speed changes.

[0064] Furthermore, the present invention is not limited to the embodiments described above, but also includes configurations in which the components disclosed in the embodiments described above are substituted for each other or combined in different ways. In addition, the technical scope of the present invention is not limited to the embodiments described above, but extends to the matters described in the claims and their equivalents. [Explanation of Symbols]

[0065] 1. Planetary gear transmission 2 Input axes 3. Transmission mechanism 4 Output shafts 5. Planetary Mechanism 30 Input Gears 31 Gearbox 32 Gear shift input gear 32a Gear body 32b Gear Cog 32c recess 33 Bevel gear 33a Gear body 33b Gear Cog 33c central part 33d hole 33e Peripheral area 34 Power transmission shaft 35 Constant velocity joint 50 Sun Gear 50a Gear Cog 51 Planetary gear 51a Gear Cog 52 Planetary Carriers 52a Rotating shaft main body 52b Rotation transmission arm section 52c Rotating support part 53 Internal gear 53a Gear body 53b Gear section 53c Bottom wall 53d Side wall part 53e Gear Cog 70,71 Friction wheel C1,C2,C3,C4 Axis

Claims

1. A speed control mechanism that changes the rotational speed of the input shaft, A planetary gear mechanism that changes the output rotational speed according to the difference between the rotational speed adjusted by the aforementioned speed change mechanism and the rotational speed of the input shaft, It has, The aforementioned gear shifting mechanism is An input gear is connected to the aforementioned input shaft so as to be rotatable together with it, A gear change gear meshed with the aforementioned input gear, A power transmission shaft connected to the aforementioned gearbox and extending in a direction along the axis of the gearbox, A constant velocity joint is provided at the tip of the power transmission shaft, A variable speed input gear is rotatably connected to the constant velocity joint, A bevel gear meshed with the aforementioned gear shift input gear, Equipped with, The aforementioned planetary mechanism section is Connected to one end of the input shaft A sun gear is connected to one end of the input shaft so as to be synchronously rotatable with the input shaft, An internal gear is provided around the aforementioned sun gear so as to be rotatable about the axis of the sun gear, A planetary gear is provided between the sun gear and the internal gear, and meshes with the sun gear and the internal gear. A planetary carrier is configured to be rotatable around the axis of the sun gear, while rotatably supporting the planetary gears. Equipped with, The base end of the planetary carrier is connected to the bevel gear so as to be rotatable together, A planetary gear type transmission characterized in that the rotational speed of the output shaft connected to the internal gear can be adjusted according to the difference in rotational speed between the sun gear connected to the tip of the input shaft and the planetary carrier.

2. The planetary gear type transmission according to claim 1, characterized in that the meshing position between the speed input gear and the bevel gear is freely displaceable around the constant velocity joint.

3. The aforementioned speed change input gear has a gear cog on its outer surface, The planetary gear type transmission according to claim 1 or 2, characterized in that the width of the gear cog is configured to gradually narrow from one end to the other.

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