Continuously variable transmission using bevel gears

Abstract

To provide a continuously variable transmission that reduces the installation space required for performing continuous speed variation, reduces energy loss during speed change as much as possible, and achieves high power transmission efficiency.SOLUTION: The continuously variable transmission includes an input bevel gear provided at the tip of an input shaft, an output gear provided at the tip of an output shaft, and an output gear tilting mechanism operationally connected to the output gear. By making the meshing position between the output gear and the input bevel gear displaceable through the output gear tilting mechanism, the transmission rotational speed from the output gear to the input bevel gear can be varied.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a continuously variable transmission using a bevel gear. [Background technology]

[0002] Conventionally, continuously variable transmissions change speed by changing the gear ratio between engaged gears, as shown in FIG. 7. The transmission in FIG. 7 has two disk-shaped friction wheels 70, 71 with mutually orthogonal rotation axes. Power can be transmitted from one friction wheel 70 to the other friction wheel 71 by bringing the rolling surface 70a of one friction wheel 70 into contact with the peripheral edge 71a of the other friction wheel 71. In this transmission, speed is changed by varying the rotation ratio of one friction wheel 71 to the other friction wheel 70, depending on the radial position of the rolling surface 70a of the one friction wheel 70 at which the peripheral edge 71a of the other friction wheel 71 is brought into contact. In such a transmission, the contact pressure between the driving side friction wheel 70 and the driven side friction wheel 71 is set high to ensure reliable power transmission between the driving side friction wheel 70 and the driven side friction wheel 71.

[0003] However, if the contact pressure between the two friction wheels 70, 71 is set too high, the rolling surface 70a and the peripheral edge 71a come into contact with each other, causing wear, and the life of the device is significantly shortened.

[0004] As means for solving such problems, the technologies described in Patent Documents 1 and 2 are disclosed. Patent Document 1 describes a gear configuration that has an input rotor that is movable back and forth along a horizontally installed input shaft and is biased forward by a biasing member attached to the input shaft, and an output rotor that is movable up and down along a vertically installed output shaft that is perpendicular to the input shaft and is biased upward by a biasing member attached to the output shaft, and that allows the rotation radius to be continuously adjusted as desired depending on the fitting position between the input rotor and the output rotor, thereby enabling continuous speed change. This configuration makes it possible to change speed depending on the contact position between the output rotor and the input rotor.

[0005] Furthermore, Patent Document 2 describes a continuously variable transmission that is composed of a conical triple gear, an inverted conical triple gear that is the conical triple gear turned upside down, and an intermediate gear that transmits rotational power from one triple gear to the other triple gear, and that allows the intermediate gear to move diagonally up and down along the inclined surfaces of the tooth profiles of the conical triple gear and the inverted conical triple gear, thereby enabling continuous speed change. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-153190 [Patent Document 2] Japanese Patent Application Publication No. 2017-190864 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0007] However, although the above-mentioned Patent Documents 1 and 2 achieve a space-saving function of minimizing the installation space, they are not capable of realizing high power transmission efficiency.

[0008] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a continuously variable transmission that reduces the installation space required when changing gears, reduces energy loss when changing gears as much as possible, and achieves high power transmission efficiency. [Means for solving the problem]

[0009] The continuously variable transmission device using bevel gears according to the present invention is composed of an input bevel gear provided at the tip of the input shaft, an output gear provided at the tip of the output shaft, and an output gear tilting mechanism connected in conjunction with the output gear, and is characterized in that the meshing position between the output gear and the input bevel gear can be freely displaced via the output gear tilting mechanism, thereby making it possible to change the rotational speed transmitted from the output gear to the input bevel gear.

[0010] Another aspect of the present invention is a continuously variable transmission using a bevel gear, characterized in that the output gear provided on the output shaft is configured so that the gear cog width gradually narrows toward one end.

[0011] Another aspect of the present invention is a continuously variable transmission using bevel gears, characterized in that the gear cog width of the input bevel gear is synchronized with the gear cog width of the output gear.

[0012] Another aspect of the present invention is a continuously variable transmission using bevel gears, characterized in that the input and output of both the input bevel gear and the output gear can be reversed.

[0013] Another aspect of the present invention is a continuously variable transmission using bevel gears, characterized in that the cog rows of the input bevel gear are formed in semicircular arc shapes that are convex upward in the radial direction of the input bevel gear, and are configured so that the cog side surfaces of each cog row come into surface contact as much as possible in response to tilting of the output gear. [Effects of the Invention]

[0014] This invention is composed of an input bevel gear provided at the tip of the input shaft, an output gear provided at the tip of the output shaft, and an output gear tilting mechanism interlocked with the output gear. By freely displacing the meshing position between the output gear and the input bevel gear via the output gear tilting mechanism, the number of rotations transmitted from the output gear to the input bevel gear can be freely changed. In addition, the output gear provided on the output shaft is configured so that the gear cog width gradually narrows toward one end, and the gear cog width of the input bevel gear is synchronized with the output gear width. In addition, the input and output of both the input bevel gear and the output gear can be reversed, and this continuously variable transmission device is configured so that the cog rows of the input bevel gear are formed in a semicircular arc shape that is convex upward in the radial direction of the input bevel gear, and the cog sides of each cog row come into surface contact as much as possible in accordance with the tilting of the output gear.As a result, the meshing position with the input bevel gear can be displaced in accordance with the amount of tilting of the output gear by the output gear tilting mechanism, thereby making it possible to continuously change the rotational speed of the input and output shafts connected to each gear.

[0015] In particular, by providing a constant velocity joint mechanism at the connection between the input bevel gear and the input shaft, the rotational driving force of the input shaft can be reliably transmitted to the output gear without reducing power transmission efficiency, and furthermore, the attitude of the input bevel gear can be displaced around the tip of the input / output shaft, allowing for fine adjustment of the meshing position with each group of conical gears to achieve stepless speed changes.

[0016] Furthermore, in this continuously variable transmission, the cog rows of the input bevel gear are formed in a semicircular arc shape that is convex upward in the radial direction of the input bevel gear, and the cog sides of each cog row are configured to make surface contact as much as possible in response to the tilting of the output gear. This reduces the amount of displacement of the device, and has the effect of making the entire continuously variable transmission device more compact.

[0017] Furthermore, the cog row of the input bevel gear is formed in a semicircular arc shape that is convex upward in the radial direction of the input bevel gear, and is configured so that the cog sides of each cog row abut in surface contact as the output gear tilts, thereby ensuring that the power of the output gear is transmitted reliably to the input bevel gear, and further ensuring that power is transmitted reliably from the input bevel gear to the output gear. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a perspective view showing a continuously variable transmission using a bevel gear according to an embodiment of the present invention; [Figure 2] FIG. 3 is a diagram showing an output gear of a continuously variable transmission according to one embodiment of the present invention. [Figure 3] FIG. 2 is a front perspective view showing an output gear of a continuously variable transmission according to one embodiment of the present invention. [Figure 4] FIG. 2 is a rear perspective view showing an output gear of a continuously variable transmission according to one embodiment of the present invention. [Figure 5] 1A and 1B are schematic diagrams showing the speed change state of a continuously variable transmission using a bevel gear according to one embodiment of the present invention, in which (a) is a diagram showing a low-speed state, (b) is a diagram showing a high-speed state, and (c) is a schematic diagram showing the displacement of an output gear from the low-speed state to the high-speed state. [Figure 6] FIG. 10 is a schematic diagram showing a continuously variable transmission using a bevel gear according to another embodiment of the present invention. [Figure 7] FIG. 1 is a schematic diagram showing a conventional continuously variable transmission. DETAILED DESCRIPTION OF THE INVENTION

[0019] The gist of this invention relates to a continuously variable transmission M using bevel gears, which is composed of an input bevel gear 1 provided at the tip of an input shaft 11, an output gear 2 provided at the tip of an output shaft 21, and an output gear tilting mechanism 3 interlocked with the output gear 2, and is characterized in that the meshing position between the output gear 2 and the input bevel gear 1 can be freely displaced via the output gear tilting mechanism 3, thereby making it possible to change the rotation speed transmitted from the output gear 2 to the input bevel gear 1.

[0020] The output gear 2 provided on the output shaft 21 is characterized in that the width of the gear cogs 22 gradually narrows toward one end, and the width between adjacent gear cogs 12 of the input bevel gear 1 is synchronized with the width of the gear cogs 22 of the output gear 2, and the input and output of both the input bevel gear 1 and the output gear 2 can be reversed.

[0021] In addition, the gear cogs 12 of the cog row of the input bevel gear 1 are formed in a semicircular arc shape that is convex upward in the radial direction of the input bevel gear 1, and are characterized in that the cog side surfaces 12a and 22a of each gear cog come into surface contact with each other in accordance with the tilting of the output gear 2, thereby abutting over as wide an area as possible.

[0022] The configuration of the continuously variable transmission M according to this embodiment will be described with reference to Figs. 1 to 5. Fig. 1 is an overall perspective view showing the configuration of the continuously variable transmission M using an input bevel gear 1. Figs. 2 to 4 are views showing an output gear 2 that constitutes the continuously variable transmission M. Fig. 5 is a schematic diagram showing the mode of power transmission by the continuously variable transmission M, in which (a) is a perspective view showing the power transmission state in a low-speed state, (b) is a perspective view showing the power transmission state in a high-speed state, and (c) is a diagram showing the movement of the output gear 2 when changing speeds.

[0023] An embodiment of the present invention is a bevel gear-based continuously variable transmission M including an input bevel gear 1 connected to the tip of an input shaft 11 via a constant velocity joint, an output gear 2 connected to the tip of an output shaft 21, and an output gear tilting mechanism 3 interlocked with the base end of the output shaft 21 via a constant velocity joint 31. The meshing position between the output gear 2 and the input bevel gear 1 can be freely displaced via the output gear tilting mechanism 3, thereby changing the rotation speed transmitted from the output gear 2 to the input bevel gear 1. The output gear 2 provided at the tip of the output shaft 21 is configured such that the width of the gear cogs 22 gradually narrows toward one end (tip). The width between adjacent gear cogs 12 of the input bevel gear 1 is also set to the same width as the width of the gear cogs 22 of the output gear 2. The input and output roles of the input bevel gear 1 and the output gear 2 can both be reversed.

[0024] An embodiment of a continuously variable transmission M using a bevel gear according to the present invention will be described in detail below with reference to the drawings. As shown in Fig. 1, the present invention comprises an input bevel gear 1 provided at the tip of an input shaft 11, an output gear 2 provided at the tip of an output shaft 21, and an output gear tilting mechanism 3 interlocked with the output gear 2.

[0025] The meshing position between the output gear 2 and the input bevel gear 1 is displaced via the output gear 2, thereby changing the rotation speed transmitted from the output gear 2 to the input bevel gear 1. In other words, the continuously variable transmission M changes speed by adjusting the meshing position between the input bevel gear 1 and the output gear 2 by displacing the output gear 2.

[0026] As shown in FIG. 1, the general configuration of the present invention comprises an input bevel gear 1 provided at the tip of an input shaft 11, an output gear 2 provided at the tip of an output shaft 21, and an output gear tilting mechanism 3 interlocked and connected to the base end of the output shaft 21.

[0027] The continuously variable transmission M changes the rotation speed of the transmission cog transmitted from the output gear 2 to the input bevel gear 1 by displacing the meshing position between the output gear 2 and the input bevel gear 1 via the output gear tilting mechanism 3. In other words, the continuously variable transmission M can adjust the rotation speed transmitted from the output gear 2 to the input bevel gear 1 depending on whether the meshing position between the output gear 2 and the input bevel gear 1 is at the tip or base end of the input bevel gear 1.

[0028] 2 to 4, the output gear 2 provided on the output shaft 21 is characterized in that the width of the gear cogs 22 gradually narrows toward one end (from the base end to the tip end in this embodiment). The gear cogs 12 of the input bevel gear 1 are spaced apart at a width that is in sync with the width of the gear cogs 22 of the output gear 2. In this embodiment, the input bevel gear 1 and the output gear 2 are described as being on the driving side and the input bevel gear 1 as being on the driven side, but in the present invention, the input bevel gear 1 can also function as the driving side and the output gear 2 as the driven side.

[0029] The output gear tilting mechanism 3 has a constant velocity joint 31 connected to the base end portion of the output shaft 21, which extends rearward from the base end side of the output gear 2 along the axis C1 of the output gear 2, and an input shaft 32 vertically attached to the constant velocity joint 31 and rotatably mounted. By raising and lowering the input shaft 32, the output gear tilting mechanism 3 can adjust the angle of the output shaft 21 via the constant velocity joint 31, and change the tilt angle of the output gear 2 connected near the tip end of the output shaft 21, thereby adjusting the meshing position between the input bevel gear 1 and the output gear 2.

[0030] For example, when the input shaft 32 of the output gear tilting mechanism 3 is raised and the output gear 2 is displaced to a position close to horizontal (see FIG. 5(b)), the output gear 2 and the input bevel gear 1 mesh near the center of the input bevel gear 1, and the rotation speed of the output shaft increases. Conversely, when the input shaft 32 of the output gear tilting mechanism 3 is lowered and the output gear 2 is displaced to a position inclined upward from the base end to the tip end (see FIG. 5(a)), the output gear 2 meshes near the periphery of the input bevel gear 1, and the rotation speed of the output shaft decreases. Such operation of the output gear 2 is performed by the output gear tilting mechanism 3 connected to the base end of the output shaft 21 of the output gear 2. In other words, the meshing position of the output gear 2 and the input bevel gear 1 can be easily changed by operating the output gear tilting mechanism 3. Furthermore, since the input shaft 32 and the output shaft 21 are connected via a constant velocity joint 31, the rotational power of the input shaft 32 can be transmitted to the output shaft 21 without loss regardless of the angle at which the input shaft 32 and the output shaft 21 are connected.

[0031] By operating the output gear tilting mechanism 3 in accordance with the selection of the meshing position between the input bevel gear 1 and the output gear 2, the meshing position between the input bevel gear 1 and the output gear 2 can be changed, and the speed change form of the continuously variable transmission M can be changed.

[0032] To explain a specific form of the continuously variable transmission M described in the embodiment, the gear cogs 22 of the output gear 2 are formed to be tapered from the tip end to the base end, and the tapered width is formed to correspond to the spacing width between adjacent gear cogs 12 of the input bevel gear 1. By making the tapered width of the output gear 2 (the width of the gear cogs 22) a harmonic width corresponding to the width between adjacent gear cogs 12 of the input bevel gear 1, the gear cogs 22 of the output gear 2 can be fitted loosely between the gear cogs 12 of the input bevel gear 1. That is, the tapered gear cogs 22 of the output gear 2 are loosely fitted into the tapered recesses between the adjacent gear cogs 12 of the input bevel gear 1, and the cog side surfaces 22a of the gear cogs 22 press against the cog side surfaces 12a of the gear cogs 12, thereby transmitting the rotational power of the output gear 2 to the input bevel gear 1. Moreover, speed changes are possible by determining which parts of the gear cogs 22 of the output gear 2 mesh with which parts of the gear cogs 12 of the input bevel gear 1.

[0033] For example, when the wide portion (base end side) of the gear cog 22 of the output gear 2 is meshed with the vicinity of the outer periphery of the gear cog 12 of the input bevel gear 1, the rotation speed of the input bevel gear 1 becomes slow, whereas when the narrow portion (tip end side) of the gear cog 22 of the output gear 2 is meshed with the vicinity of the center of the gear cog 12 of the input bevel gear 1, the rotation speed becomes high. In this way, the rotation speed of the input bevel gear 1 can be adjusted by meshing the vicinity of the base end of the gear cog 22 of the output gear 2, which is configured to be wide, with the gear cog 12 near the outer periphery of the input bevel gear 1, or by meshing the vicinity of the tip end of the gear cog 22 of the output gear 2, which is configured to be narrow, with the gear cog 12 near the outer periphery of the input bevel gear 1.

[0034] Furthermore, when adjusting the meshing position between the input bevel gear 1 and the output gear 2, the output gear 2 tilts along the curved surface of the gear cog 12 of the input bevel gear 1, thereby continuously changing the meshing position between the output gear 2 and the input bevel gear 1. In other words, by configuring the upper surface of the gear cog 12 of the input bevel gear 1 to be curved in an upward convex shape from near the center of the input bevel gear 1 to near the periphery, the output gear 2 can be continuously displaced along the curved surface of the gear cog 12, and the rotational speed of the output shaft can be changed continuously.

[0035] Furthermore, in the above-described embodiment, a configuration has been described in which the input bevel gear 1 is fixed and the output gear 2 tilts along the circumferential surface of the gear cog 12 of the input bevel gear 1. However, the present invention is not limited to this, and the input bevel gear 1 may be tilted to adjust the meshing position with the output gear 2. By configuring the input bevel gear 1 to be tiltable in this manner, the tilting range of the output gear 2 by the output gear tilting mechanism 3 can be reduced, allowing the continuously variable transmission M to be more compact than if the speed were changed by tilting the output gear 2 alone. Note that, because the input bevel gear 1 is connected to the input shaft 11 via a constant velocity joint, there is no risk of a decrease in the transmission efficiency of rotational power even if the connection angle between the input bevel gear 1 and the input shaft 11 is changed.

[0036] Furthermore, as shown in FIG. 6 , the continuously variable transmission M of the present invention is configured such that one of two input bevel gears 1,1 is inverted and the flat bottom surfaces are joined to form an integrated input bevel gear 4, and output gears 2,2 are provided on the outer peripheral surfaces of the upper and lower input bevel gears 1,1 that constitute the input bevel gear 4, respectively, thereby making it possible to individually adjust the rotation speed transmitted to each output gear 2,2. In other words, by meshing the input bevel gear 4 with the output gears 2,2 at different meshing positions, the rotation speed transmitted from the input bevel gear 4 to the output gears 2,2 can be changed. For example, if the meshing position between the input bevel gear 1 located at the top of FIG. 6 and the upper output gear 2 is near the center of the upper input bevel gear 1 and the meshing position between the input bevel gear 1 located at the bottom of FIG. 6 and the lower output gear 2 is near the periphery of the lower input bevel gear 1, the upper output gear 2 rotates at a high speed and the lower output gear 2 rotates at a slower speed. In this way, by configuring each output gear 2 so that it can be displaced individually by the output gear tilting mechanism 3 connected to the base end of the output shaft 21, it is possible to realize rotation of two different transmitted rotational speeds from one input bevel gear 4.

[0037] The present invention is not limited to the above-described embodiments, but also includes configurations in which the configurations disclosed in the above-described embodiments are mutually substituted or combined. Furthermore, the technical scope of the present invention is not limited to the above-described embodiments, but extends to the matters set forth in the claims and their equivalents. [Explanation of symbols]

[0038] 1 Input bevel gear 2 output gears 3. Output gear tilting mechanism 4 Input bevel gear 11 Input shaft 12 gear cog 12a Cog Side 21 Output shaft 22 gear cog 22a Cog Side 31 Constant velocity joint 32 Input shaft 70,71 Friction wheel M continuously variable transmission

Claims

1. an input bevel gear provided at the tip of the input shaft; an output gear provided at the tip of the output shaft; an output gear tilting mechanism interlocked with the output gear, the input bevel gear has gear cogs formed in an upwardly convex curve; The output gear is formed to be shorter than the overall length of the gear cogs of the input bevel gear, A continuously variable transmission using bevel gears, characterized in that the meshing position between the output gear and the input bevel gear can be freely displaced by raising and lowering the input shaft that constitutes the output gear tilting mechanism, thereby making it possible to change the number of rotations transmitted from the output gear to the input bevel gear.

2. A continuously variable transmission using bevel gears as described in Claim 1, characterized in that the output gear is configured so that the gear cog width gradually narrows toward one end.

3. A continuously variable transmission using bevel gears as described in claim 1 or claim 2, characterized in that the input and output of both the input bevel gear and the output gear can be reversed.

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