Continuously variable transmission mechanism

Abstract

To provide a continuously variable transmission mechanism that is capable of mechanically performing continuously variable transmission without the use of a high-cost device such as an inverter.SOLUTION: A continuously variable transmission mechanism comprises: an input-side worm gear body configured to have a gradually changing spiral pitch of a spiral screw gear formed on a circumferential surface of a gear shaft body; an output-side wheel gear body configured such that an engagement position thereof can be adjusted so as to engage the worm gear body at any position; and an adjustment operation part that is disposed contiguously to and interlocked with the wheel gear body and / or worm gear body in order to adjust the engagement position of the wheel gear body and worm gear body. The continuously variable transmission mechanism is also configured such that a gear rotational speed from the input side can be changed to a continuously variable gear rotational speed on the output side by operation of the adjustment operation part.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a continuously variable transmission mechanism that can not only decelerate but also shift gears.

Background Art

[0002] Conventionally, as one of the deceleration mechanisms, there is known a worm gear mechanism composed of a worm gear body (worm shaft) made of a screw gear, which is a kind of helical gear, and a wheel gear body generally having a larger diameter than the worm gear body, which is composed of a spur gear or a helical gear that meshes with the worm gear body (for example, Patent Document 1).

[0003] FIG. 9 is a perspective view showing a conventional worm gear mechanism. Usually, as shown in FIG. 9, by using a worm gear body W1, which is a screw gear, as an input shaft IS and using a wheel mounting shaft with a wheel gear body W2 mounted thereon as an output shaft OS, the output shaft OS can be rotated at a large reduction ratio (for example, 10 or more) with respect to the input shaft IS. Further, the worm gear mechanism is also characterized in that the direction of the output shaft OS can be set to a direction intersecting the input shaft IS, including a direction orthogonal thereto.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the above-described conventional worm gear mechanism, since the helix pitch of the gear teeth W11 of the worm gear body W1 that meshes with the gear teeth W21 of the wheel gear body W2 is constant, although it is possible to decelerate at a large reduction ratio, the reduction ratio cannot be changed. Therefore, in order to change the reduction ratio, it is necessary to separately use an inverter or the like, but since the inverter or the like is expensive, there is a problem in terms of cost.

[0006] The present invention has been made in view of such problems, and an object thereof is to provide a continuously variable transmission mechanism that can mechanically perform continuously variable transmission in addition to speed reduction without using an expensive device such as an inverter.

Means for Solving the Problems

[0007] In order to solve the above problems, the continuously variable transmission mechanism according to the present invention includes an input-side worm gear body configured by gradually changing the spiral pitch of a spiral screw gear formed on the peripheral surface of a gear shaft body, and an output-side wheel gear body configured to be able to adjust the meshing position so as to mesh at an arbitrary position of the worm gear body, and an adjustment operation unit interlocked and connected to the wheel gear body or the worm gear body or both gears for adjusting the meshing position and the meshing state between the wheel gear body and the worm gear body, and is characterized in that the rotational speed of the gear from the input side can be shifted to a continuously variable rotational speed on the output side by operating the adjustment operation unit.

[0008] Further, the continuously variable transmission mechanism according to the present invention includes a longitudinally rod-shaped wheel gear body having gear teeth formed on its peripheral surface, and a worm gear body meshing with the gear teeth on the peripheral surface of the wheel gear body. The wheel gear body has a tapered shape in which the diameter gradually increases or decreases from one end to the other end, and the worm gear body is movable along the peripheral surface of the wheel gear body while the gear teeth on the peripheral surface mesh with the gear teeth on the peripheral surface of the wheel gear body. The rotational speed from the worm gear body is continuously variable and transmitted to the wheel gear body according to the gear position on the peripheral surface of the wheel gear body with which the worm gear body meshes.

Effects of the Invention

[0009] According to the present invention, there is provided a continuously variable transmission mechanism comprising: a worm gear body configured by gradually changing the spiral pitch of a spiral screw gear formed on the circumferential surface of a gear shaft body; a wheel gear body configured to be adjustable in engagement position so as to engage at an arbitrary position of the worm gear body; and an adjustment operation unit interlocked and connected to the wheel gear body, the worm gear body, or both gears for adjusting the engagement position between the wheel gear body and the worm gear body. By configuring the continuously variable transmission mechanism such that the rotational speed of the gear input from the input side can be mechanically shifted to a continuously variable rotational speed on the output side by operating the adjustment operation unit, it is possible to provide a continuously variable transmission mechanism that can mechanically perform continuously variable speed change in addition to speed reduction without using an expensive device such as an inverter.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

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Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Embodiments for Carrying Out the Invention

[0011] The gist of the present invention is to provide an input-side worm gear body configured by gradually changing the spiral pitch of a spiral screw gear formed on the peripheral surface of a gear shaft body, an output-side wheel gear body configured to be able to adjust the meshing position so as to mesh at an arbitrary position of the worm gear body, and an adjustment operation part interlocked and connected to the wheel gear body or the worm gear body or both gears for adjusting the meshing position between the wheel gear body and the worm gear body, and to provide a continuously variable transmission mechanism configured to be able to shift the gear rotation speed from the input side to a continuously variable gear rotation speed on the output side by operating the adjustment operation part.

[0012] Further, it is composed of a longitudinal rod-shaped wheel gear body having gear teeth formed on its peripheral surface, and a worm gear body that meshes with the gear teeth on the peripheral surface of the wheel gear body. The wheel gear body has a tapered shape with a diameter gradually increasing or decreasing from one end to the other end. The worm gear body is such that the gear teeth on its peripheral surface mesh with the gear teeth on the peripheral surface of the wheel gear body and can move freely along the peripheral surface of the wheel gear body. According to the gear position on the peripheral surface of the wheel gear body with which the worm gear body meshes, the rotation speed from the worm gear body is steplessly changed and transmitted to the wheel gear body, and the object is to provide a stepless speed change mechanism.

[0013] <First Embodiment> Hereinafter, the stepless speed change mechanism A according to the first embodiment will be described in detail with reference to the drawings. FIG. 1 is a schematic plan view showing the basic configuration of the stepless speed change mechanism A.

[0014] As shown in the drawing, the stepless speed change mechanism A generally includes: (1) A plurality (four in this embodiment) of input-side worm gear bodies 1 formed by gradually changing the spiral pitch of the spiral gear teeth 12 formed on the peripheral surface of the gear main body 11 as a gear shaft body; (2) An output-side wheel gear body 2 configured to be adjustable in the meshing position so as to mesh at an arbitrary position (meshing position) of the worm gear body 1; (3) An adjustment operation unit 3 interlocked and connected to the wheel gear body 2 or the worm gear body 1 or both gear bodies 1 and 2 for adjusting the meshing position between the wheel gear body 2 and the worm gear body 1. It is composed of the above.

[0015] The worm gear body 1 is an input-side gear body that meshes with the wheel gear body 2 to transmit the rotational force. As shown in FIG. 1, the worm gear body 1 includes an input shaft 10 that is rotationally driven, a columnar gear main body 11 that rotates integrally with the input shaft 10, and gear teeth 12 that are formed spirally along the axial direction on the outer peripheral surface of the gear main body 11.

[0016] As shown in FIGS. 1 to 3, the gear teeth 12 of the worm gear body 1 are a single helical ridge continuously formed on the outer peripheral surface of the gear body 11, and the helical pitch is gradually enlarged or reduced from one end to the other end on the outer peripheral surface of the gear body 11. The gear teeth 12 are formed with a gear width and a gear height that meshes with the gear teeth 22 of the wheel gear body 2.

[0017] A plurality of such worm gear bodies 1 are arranged in parallel in the same axial direction of the input shaft 10. The number of worm gear bodies 1 of the continuously variable transmission mechanism A of this embodiment is 4, but it may be 1, or may be 2, 3, or 5 or more.

[0018] As shown in FIGS. 3, 4(a) and 4(b), the wheel gear body 2 is configured as a spur gear having a plurality of gear teeth 22 which are long meshing teeth (cogs) provided at regular intervals extending along the axial direction on its outer peripheral surface. Note that the wheel gear body 2 is not limited to a spur gear and may be formed of a helical gear.

[0019] Specifically, the wheel gear body 2 is an output-side gear body that meshes with the worm gear body 1 and rotates by receiving the rotational force from the worm gear body 1. The wheel gear body 2 includes an output shaft 20, a cylindrical gear body 21 that rotates integrally with the output shaft 20, and a plurality of gear teeth 22 formed on the outer peripheral surface of the gear body 21.

[0020] As shown in FIG. 2 or FIG. 3, the gear teeth 22 of the wheel gear body 2 are ridges linearly formed along the axial direction on the outer peripheral surface of the gear body 21, and a plurality of them are formed while maintaining a constant pitch in the circumferential direction. That is, the wheel gear body 2 inserts the gear teeth 12 of the worm gear body 1 into the gear grooves between adjacent gear teeth 22 to mesh with the worm gear body 1.

[0021] Further, the wheel gear body 2 is formed in a long shape. The length of the wheel gear body 2 is set to be at least long enough to mesh with a plurality of worm gear bodies 1 located below. Thereby, the continuously variable transmission mechanism A can change the number of worm gear bodies 1 meshing with the wheel gear body 2 according to the required torque amount on the output shaft side. For example, when the transmitted power transmitted to the output shaft side is small, the number of worm gear bodies 1 can be set to one, and the power of the entire continuously variable transmission mechanism A can be set low.

[0022] The adjustment operation unit 3 is configured such that by its operation, the gear rotation speed of the input-side worm gear body 1 is transmitted to the output-side wheel gear body 2 at a constant reduction ratio, and by adjusting the meshing position of the gear teeth 12 of the worm gear body 1 and the gear teeth 22 of the wheel gear body 2, the gear rotation speed can be continuously and steplessly shifted.

[0023] As shown in FIG. 1, such a continuously variable transmission mechanism A has, in a plan view, four worm gear bodies 1, 1, 1, 1 obliquely intersecting the wheel gear body 2 by an oblique intersection angle α (the axial intersection angle of the input shaft 10 of the worm gear body 1 with respect to the orthogonal direction of the output shaft 20 of the wheel gear body 2) through the adjustment operation unit 3 and meshing therewith.

[0024] That is, the worm gear bodies 1, 1, 1, 1 are configured to be movable by the adjustment operation unit 3 so that the oblique intersection angle of the input shaft 10 with respect to the output shaft 20 of the wheel gear body 2 can be made variable.

[0025] As shown in FIG. 1, the continuously variable transmission mechanism A has a rectangular box-shaped mount 4, and the mount 4 is provided with a worm gear body 1 and a wheel gear body 2. The mount 4 is configured to have a bottom plate 40, a pair of output-side support portions 41, 41' standing upright facing each other on the bottom plate 40, and input-side support portions 42, 42' standing upright on the bottom plate 40.

[0026] A pair of output-side support portions 41, 41' are provided opposite to each other at a certain interval on the left and right sides of the bottom plate 40, and above each worm gear body 1, 1, 1, 1, the wheel gear body 2 is rotatably mounted on a shaft at a certain height. That is, the output-side support portions 41, 41' function as bearings that rotatably support both ends of the output shaft 20 of the wheel gear body 2.

[0027] Note that an output conversion mechanism (not shown) that rotates integrally with the wheel gear body 2 is attached to one end of the output shaft 20 of the wheel gear body 2, and it is configured to output the rotational power that is steplessly shifted by the worm gear body 1 and the adjustment operation portion 3 and transmitted to the wheel gear body 2.

[0028] Also, inside the gantry 4, as shown in FIG. 1, four worm gear bodies 1, 1, 1, 1 forming the input side having the same shape and the same length extend in an inclined state in the left-right direction of the gantry 4 in a plan view. Each worm gear body 1, 1, 1, 1 is arranged at the same skew angle α (60° in FIG. 1) with respect to the wheel gear body 2 and at a certain interval from each other with the input shafts 10, 10, 10, 10 parallel to each other.

[0029] Each worm gear body 1, 1, 1, 1 is rotatably pivotally supported between a pair of long input-side support portions 42, 42' arranged inside the gantry 4 and is provided so as to be horizontally swingable inside the gantry 4. Specifically, each worm gear body 1 is horizontally rotatably pivotally supported by a rotating shaft 30 provided at one end of the input shaft 10 on one input-side support portion 42, and the other end of the input shaft 10 is horizontally rotatably pivotally supported by a rotating shaft 50 provided on the other input-side support portion 42', and horizontally swings while maintaining a parallel state with each other inside the gantry 4.

[0030] The right ends of the input shafts 10, 10, 10, 10 of each worm gear body 1, 1, 1, 1 are pivotally connected to a rotating shaft 50 (see FIGS. 6(a) to 6(c)) attached to the right input-side support portion 42' via a pair of bevel gears 13, 51.

[0031] In addition, the left end portions of the input shafts 10, 10, 10, 10 of the respective worm gear bodies 1, 1, 1, 1 are pivotally connected to the left input side support portion 42 via the rotating shaft 30 (see FIG. 1).

[0032] In this way, the continuously variable transmission mechanism A forms a worm gear body support frame 6 having a parallelogram shape in plan view that can be changed in shape by the right input side support portion 42', the left input side support portion 42, the worm gear body 1 arranged at the uppermost stage, and the worm gear body 1 arranged at the lowermost stage (see FIG. 1).

[0033] Sprocket wheels (not shown) are attached to the respective rotating shafts 50 disposed on the right input side support portion 42'. The sprocket wheels are tandem-connected to each other by a plurality of endless chains 52, 52, 52.

[0034] A large reduction gear 53 is fixed to the rotating shaft 50 at the uppermost stage, and the large reduction gear 53 meshes with a small reduction gear 54. The small reduction gear 54 is connected to a worm gear body driving motor (not shown) as a driving portion.

[0035] That is, when the worm gear body driving motor as the driving portion is driven, the small reduction gear 54 and the large reduction gear 53 rotate, and the respective rotating shafts 50, 50, 50, 50 are rotationally driven via the endless chains 52, 52, 52. As the rotating shafts 50 rotate, the bevel gears 51, 13 rotate, so that the four worm gear bodies 1, 1, 1, 1 rotate synchronously about their axes.

[0036] The adjustment operation portion 3 is an operation portion that can adjust the skew angle α of the worm gear body 1 with respect to the wheel gear body 2. This adjustment operation portion 3 will be described with reference to FIGS. 1 and 6(a) to 6(c).

[0037] The adjustment operation portion 3 can change the skew angle α of the worm gear body 1 with respect to the wheel gear body 2 by changing the form of the worm gear body support frame 6 as shown in FIGS. 6(a) to 6(c) by a drive mechanism that adjusts the adjustment operation portion 3.

[0038] Incidentally, as described above, if only the input-side worm gear body 1 configured by gradually changing the spiral pitch of the spiral worm gear formed on the peripheral surface of the gear shaft body is adopted, as shown in FIG. 1, due to the change in the spiral pitch of the worm gear body 1, the twist angle of the worm gear changes. Therefore, as it is, it is difficult to ensure good meshing between the gear teeth 12 of the worm gear body 1 and the gear teeth 22 of the wheel gear body 2.

[0039] Therefore, in the continuously variable transmission mechanism of the present embodiment, the meshing position between the wheel gear body 2 and the worm gear body 1 is adjusted by changing the skew angle α of the worm gear body 1 with respect to the wheel gear body 2 using the adjustment operation portion 3.

[0040] The adjustment operation portion 3 can be easily configured, for example, by connecting the tip of a telescopic cylinder (not shown) to the middle portion of the left input-side support portion 42. That is, the adjustment operation portion 3 is composed of a telescopic cylinder and the left input-side support portion 42 that moves by the telescopic operation of the telescopic cylinder.

[0041] In other words, each worm gear body 1 rotates horizontally about the rotation axis 50 of the right input-side support portion 42' that rotatably supports the other end portion of the input shaft 10 together with the left input-side support portion 42 that rotatably supports one end portion of the input shaft 10 as the telescopic cylinder of the adjustment operation portion 3 expands and contracts.

[0042] That is, the input shaft 10 of the worm gear body 1 is configured as a movable shaft that has a fixed end portion where the other end portion is connected to the drive portion and the rotational driving force is transmitted, and a free end portion where one end portion is horizontally rotated about the rotation axis 50 at the other end portion.

[0043] Accordingly, based on the meshing position, the direction of the tooth flanks of the gear teeth 12 of the worm gear body 1 (the direction perpendicular to the cross section) and the direction of the tooth flanks of the gear teeth 22 of the wheel gear body 2 (the direction perpendicular to the cross section) are made to coincide, so that good meshing can be ensured between the gear teeth 12 of the worm gear body 1 and the gear teeth 22 of the wheel gear body 2.

[0044] That is, in FIG. 1, in this embodiment, by operating the telescopic cylinder that constitutes the adjustment operation unit 3, the form of the worm gear body support frame 6 is changed from the form shown in FIG. 6(a) to any one of the forms shown in FIGS. 6(a) to 6(c) with the rotation axis 50 that pivotally supports the right end of the input shaft 10 of the uppermost worm gear body 1 in FIG. 1 as the rotation center.

[0045] Due to the change in the form of the worm gear body support frame 6, when the telescopic cylinder retracts, the worm gear body support frame 6 has the parallelogram shape shown in FIG. 6(a) and is in the position shown by the solid line.

[0046] At this position, at the pitch portion having a 15-degree screw angle formed at one end of each worm gear body 1, the gear teeth 12 of the worm gear body 1 and the gear teeth 22 of the wheel gear body 2 mesh at a 15-degree inclination angle.

[0047] Next, when the telescopic cylinder extends to the intermediate position, the worm gear body 1 moves to the position shown by the solid line, and the worm gear body support frame 6 rotates counterclockwise around the rotation axis 50 from the form shown in FIG. 6(a) and transforms into the form on the right side of FIG. 6(b).

[0048] At this position, at the pitch portion having a 30-degree screw angle formed at one end of each worm gear body 1, the gear teeth 12 of the worm gear body 1 and the gear teeth 22 of the wheel gear body 2 mesh at a 30-degree inclination angle.

[0049] Furthermore, when the telescopic cylinder extends to its maximum length, the worm gear body 1 moves to the position shown by the solid line, and the worm gear body support frame 6 rotates counterclockwise about the rotation axis 50 from the form shown in Fig. 6(a) and transforms into the form on the right side of Fig. 6(c).

[0050] At this position, at the pitch portion with a 60-degree thread angle formed at one end of each worm gear body 1, the gear teeth 12 of the worm gear body 1 and the gear teeth 22 of the wheel gear body 2 mesh with each other at a 60-degree inclination angle.

[0051] The operation and effect of the continuously variable transmission mechanism A having the above configuration will be described. When the continuously variable transmission mechanism A drives the worm gear body driving motor, the input-side worm gear body 1 rotates, and the rotational force generated by the worm gear body driving motor is transmitted to the wheel gear body 2 and the load connected to the output side of the wheel gear body 2 through meshing with the output-side wheel gear body 2.

[0052] Also, in the continuously variable transmission mechanism A, when the telescopic cylinder, which is the adjustment operation unit 3, expands and contracts, the parallelogram of the worm gear body support frame 6 is transformed with the rotation axis 50 at the right end of the uppermost worm gear body 1 as the center of rotation, and the skew angle α of the worm gear body 1 with respect to the wheel gear body 2 can be changed.

[0053] As shown in Fig. 6(a), by positioning the pitch portion with a 15-degree thread angle formed at one end of each worm gear body 1 to coincide with the wheel gear body 2, the gear teeth 12 of the worm gear body 1 and the gear teeth 22 of the wheel gear body 2 can be meshed at a 15-degree inclination angle.

[0054] On the other hand, when the telescopic cylinder extends to the intermediate position, the worm gear body support frame 6 moves from the position shown in Fig. 6(a) to the position shown in Fig. 6(b), and the parallelogram shape of the worm gear body support frame 6 is transformed. As a result, the gear teeth 12 at the pitch portion with a 30-degree thread angle formed at the other end of each worm gear body 1 mesh with the gear teeth 22 of the wheel gear body 2 at a 30-degree angle.

[0055] Furthermore, when the telescopic cylinder is fully extended, the worm gear body support frame 6 moves from the position shown in Fig. 6(b) to the position shown in Fig. 6(c), further deforming the parallelogram shape.

[0056] As a result, the gear teeth 12 at the pitch portion having a 60-degree thread angle formed at the other end of each worm gear body 1 will mesh with the gear teeth 22 of the wheel gear body 2 at a 60-degree angle.

[0057] Also, as shown in Figs. 5(a) and 5(b), the continuously variable transmission mechanism A continuously changes the spiral pitch of the spiral gear teeth 12 formed on the peripheral surface of the gear shaft body of the worm gear body 1 between 15 degrees and 45 degrees.

[0058] Therefore, the continuously variable transmission mechanism A described in this embodiment can easily change the reduction ratio between the worm gear body 1 and the wheel gear body 2 by configuring the spiral gear teeth 12 to continuously change at angles with different spiral pitches.

[0059] That is, the continuously variable transmission mechanism A can be continuously and steplessly shifted by configuring the spiral gear teeth 12 to continuously change such that the spiral pitch expands from one end to the other end of the worm gear body 1. Also, with such a configuration, good meshing can be ensured between the gear teeth 12 of the worm gear body 1 and the gear teeth 22 of the wheel gear body 2 over the entire length of the worm gear body 1.

[0060] <Second Embodiment> Next, the continuously variable transmission mechanism A2 according to the second embodiment will be described with reference to Fig. 10. In the continuously variable transmission mechanism A according to the first embodiment described above, when adjusting the meshing position between the four worm gear bodies 1 on the input side and the wheel gear body 2 on the output side, the four worm gear bodies 1 on the input side are translated while the wheel gear body 2 is held in a fixed position.

[0061] In contrast, in the continuously variable transmission mechanism A2 according to this embodiment, when adjusting the meshing position between the four worm gear bodies 1 on the input side and the wheel gear body 2 on the output side, the worm gear body 1 on the input side is fixed, and the wheel gear body 2 on the output side is configured to be translatable in the lateral direction.

[0062] Note that since the basic configuration of the continuously variable transmission mechanism A2 according to this embodiment is the same as that of the continuously variable transmission mechanism A, only the different components will be described, and the same components will be denoted by the same reference numerals and their detailed description will be omitted.

[0063] As shown in FIG. 10, by using the worm wheel translation device 60, the wheel gear body 2 can be translated between a meshing position P1 (the position shown by the solid line) where the gear teeth 12 of the worm gear body 1 and the gear teeth 22 of the wheel gear body 2 mesh at an angle of 15 degrees, and a meshing position P2 (the position shown by the dashed line) where the gear teeth 12 of the worm gear body 1 and the gear teeth 22 of the wheel gear body 2 mesh at an angle of 60 degrees.

[0064] Specifically, the worm wheel translation device 60 includes (1) A pair of transfer screw shafts 61, 61' arranged in an extended state in a direction orthogonal to the axis of the wheel gear body 2 (the lateral direction in the drawing) at both ends of the wheel gear body 2 extending in the vertical direction in the drawing; (2) A pair of moving blocks 62, 62' that rotatably support both ends of the output shaft 20 to which the wheel gear body 2 is fixed and have screwing portions screwed to the transfer screw shafts 61, 61'; (3) Sprocket wheels 63, 63' fixed to the corresponding one ends of the transfer screw shafts 61, 61', and a wheel gear body drive motor (not shown) connected to one end of one of the transfer screw shafts 61 and functioning as an adjustment operation unit; (4) A synchronous endless chain 64 wound between the sprocket wheels 63, 63' parallel to the axis of the output shaft 20 of the wheel gear body 2.

[0065] With the above-described configuration, when the wheel gear body drive motor that forms part of the adjustment operation unit is driven, the transfer screw shafts 61, 61' rotate synchronously by the synchronous endless chain 64.

[0066] Due to this rotation, the moving blocks 62, 62' that are screwed onto the transfer screw shafts 61, 61' and the wheel gear body 2 installed between the moving blocks 62, 62' will translate.

[0067] That is, the wheel gear body 2 can translate between the meshing position P1 and the meshing position P2. Thereby, the stepless speed change mechanism A2 translates the wheel gear body 2 to adjust the meshing position with the worm gear body 1.

[0068] Specifically, based on the meshing position, the direction of the tooth flanks of the gear teeth 12 of the worm gear body 1 (the direction perpendicular to the cross-section) and the direction of the tooth flanks of the gear teeth 22 of the wheel gear body 2 (the direction perpendicular to the cross-section) are made to coincide, and the meshing position between the gear teeth 12 of the worm gear body 1 and the gear teeth 22 of the wheel gear body 2 is adjusted. By this adjustment, the gear rotation speed can be steplessly changed.

[0069] <Third Embodiment> Next, the stepless speed change mechanism A3 according to the above-described third embodiment will be described with reference to FIG. 11. In the above-described stepless speed change mechanism A, when adjusting the meshing position between the four worm gear bodies 1 on the input side and the wheel gear body 2 on the output side, with the rotation shaft 50 (see FIG. 6(a)) that pivotally supports the right end of the uppermost worm gear body 1 in FIG. 1 as the center of rotation, the worm gear body support frame 6 is deformed to translate the four worm gear bodies 1 on the input side. On the other hand, the wheel gear body 2 is held in a fixed position.

[0070] On the other hand, as shown in FIG. 11, the continuously variable transmission mechanism A3 according to this embodiment is characterized in that one end of the output shaft 20 of the wheel gear body 2 is rotatably supported by a pivot shaft 70 erected on the pedestal 4, and the other end of the output shaft 20 of the wheel gear body 2 is translated. The continuously variable transmission mechanism A3 adjusts the meshing position between the wheel gear body 2 and the worm gear body 1 according to the above-described configuration.

[0071] Specifically, based on the meshing position, the direction of the tooth flanks of the gear teeth 12 of the worm gear body 1 (the direction orthogonal to the cross section) is made to coincide with the direction of the tooth flanks of the gear teeth 22 of the wheel gear body 2 (the direction orthogonal to the cross section).

[0072] Thereby, a good meshing can be ensured between the gear teeth 12 of the worm gear body 1 and the gear teeth 22 of the wheel gear body 2.

[0073] As described above, the continuously variable transmission mechanisms A to A3 according to the first to third embodiments have been described. However, these continuously variable transmission mechanisms can also have the following configurations.

[0074] As shown in FIG. 8, within a predetermined pitch, considering the actual meshing state, the cross sections C-C, D-D, and E-E in FIG. 8(a) can also be made into an optimal shape (FIG. 8(b), FIG. 8(c), FIG. 8(d)) in order to obtain a smooth meshing.

[0075] <Fourth Embodiment> Next, the continuously variable transmission mechanism A4 of the fourth embodiment described above will be described with reference to FIGS. 12 to 15. The continuously variable transmission mechanism A4 according to this embodiment has the same configuration as the continuously variable transmission mechanism A according to the first embodiment described above in that it is composed of a longitudinally rod-shaped wheel gear body 2 having gear teeth 22 formed on its circumferential surface and a worm gear body 1 having gear teeth 12 meshing with the gear teeth 22 on the circumferential surface of the wheel gear body 2.

[0076] The difference between the continuously variable transmission mechanism A4 of this embodiment and the above-described continuously variable transmission mechanism A is that the continuously variable transmission mechanism A4 of this embodiment (1) The wheel gear body 2 has a tapered shape with a gradually increasing or decreasing diameter from one end to the other end of the gear body 210, (2) The worm gear bodies 1, 1, 1, 1 mesh the gear teeth 12 on the circumferential surface with the gear teeth 22 on the circumferential surface of the wheel gear body 2 and are movable along the circumferential surface of the wheel gear body 2, (3) It is configured to continuously variable speed the rotation speed from the worm gear bodies 1, 1, 1, 1 and transmit it to the wheel gear body 2 according to the gear position on the circumferential surface of the wheel gear body 2 with which the worm gear bodies 1, 1, 1, 1 mesh.

[0077] As shown in FIGS. 12 to 13(b), the wheel gear body 2 includes an elongated frustum-shaped or conical gear body 210 integrally externally fitted and fixed to the output shaft 20, and formed on the outer peripheral surface of the gear body 210 Co gear teeth 22 as teeth, and is constituted thereby.

[0078] The output shaft 20 is connected to the drive shaft (not shown) of the rotation drive device at a predetermined position to be speed-changed, and is pivotally supported by a predetermined bearing (not shown) provided on the mount. The gear body 210 is arranged concentrically with the center of the output shaft 20 at the center of a substantially circular shape in a cross-sectional view along the longitudinal direction (axial direction) along the axial direction of the output shaft 20, and is fixed to the output shaft 20.

[0079] As shown in FIGS. 12 to 13(b), the gear body 210 has an outer diameter gradually increasing or decreasing from one end side to the other end side in the longitudinal direction (axial direction), and the outer peripheral surface 211 is formed as a tapered surface inclined along the longitudinal direction (axial direction).

[0080] The gear teeth 22 are formed in a plurality on the outer peripheral surface 211 of the gear body 210 at a constant pitch in the circumferential direction, and tooth streaks are formed along the longitudinal direction (axial direction) of the gear body 210. Specifically, the gear teeth 22 are constituted by a plurality of gear crest portions 220 and a plurality of gear trough portions 221 alternately formed in the circumferential direction on the outer peripheral surface 211 of the gear body 210.

[0081] The tooth crest portion 220 of the gear gradually expands or contracts from one end side to the other end side so as to conform to the tapered shape of the gear body 210. That is, the tooth line shape formed by the top surface of the tooth crest portion 220 is an elongated substantially trapezoidal shape that gradually expands or contracts along the axial direction of the gear body 210 as shown in FIGS. 12 to 13(b). 、 Gi It becomes an elongated substantially trapezoidal shape that gradually expands or contracts along the axial direction of the gear body 210.

[0082] The tooth groove portion 221 has the same pitch length of the tooth groove, and is formed as a groove having a semicircular cross section between adjacent tooth crest portions 220, 220 along the axial direction of the gear body 210. That is, the groove line shape of the tooth groove portion 221 is an elongated substantially rectangular shape along the axial direction of the gear body 210 as shown in FIGS. 12 to 13(b).

[0083] Around the outer periphery of such an output-side wheel gear body 2, a plurality of input-side worm gear bodies 1, 1, 1, 1 are rotatably arranged so that the gear teeth 12 formed on the peripheral surface mesh with the gear teeth 22 of the wheel gear body 2. 0 The worm gear bodies 1, 1, 1, 1 are arranged in a cross-symmetrical shape of four around the output shaft 20 in the axial view of the wheel gear body 2.

[0084] The worm gear body 1 includes an input shaft 100 that is connected to a predetermined drive source and rotates integrally therewith and is configured to be movable along the input shaft 100, and a gear body 110 that is formed to project radially outward on the outer peripheral surface of the gear body 110, and gear teeth 120.

[0085] As shown in FIGS. 12 to 13(b), the plurality of input shafts 100, 100, 100, 100 are arranged at four equal intervals around the outer periphery of the wheel gear body 2 along the inclination of the tapered outer peripheral surface 211 of the wheel gear body 2.

[0086] Specifically, each input shaft 100, 100, 100, 100 is inclined with respect to the output shaft 20 of the wheel gear body 2 and is arranged around the outer periphery of the output shaft 20 so that a predetermined position of the output shaft 20 is the same intersection point. Each input shaft 100, 100, 100, 100 is configured to rotate synchronously in the same rotation direction and with the same rotation amount.

[0087] The gear main body 110 is in the shape of a short cylinder, into which the input shaft 100 is inserted and externally fitted to the input shaft 100. It is configured to be movable in the axial direction of the input shaft 100 but fixed to the input shaft 100 in the circumferential direction and restricted from moving.

[0088] As such a fitting structure between the worm gear body 1 and the input shaft 100, for example, a spline fitting structure in which the cylindrical hole of the gear main body 110 of the worm gear body 1 and the outer peripheral surface of the input shaft 100 are male-female fitted to each other can be adopted.

[0089] Specifically, a male-side spline fitting portion along the axial direction is formed on the outer peripheral surface of the input shaft 100, and a female-side spline fitting portion corresponding to the male-side spline fitting portion of the input shaft 100 is formed on the inner peripheral surface of the cylindrical hole of the gear main body 110, thereby constituting a fitting structure between the worm gear body 1 and the input shaft 100.

[0090] Further, the plurality of worm gear bodies 1, 1, 1, 1 are each subjected to synchronous parallel movement by the adjustment operation portion 3 so that the positions in the longitudinal direction of the outer peripheral surface 211 of the wheel gear body 2 are the same (the phases (levels) with respect to the axial direction of the input shaft 100 are the same). That is, each worm gear body 1, 1, 1, 1 performs movement along the input shaft 100 synchronized with each other by the adjustment operation portion 3 so as to always be positioned on the virtual diametral plane of the wheel gear body 2.

[0091] Such a movement configuration of each worm gear body 1, 1, 1, 1 by the adjustment operation portion 3 may be a configuration in which the gear main body 110 is moved along the input shaft 100, or may be a configuration in which the gear main body 110 integrated with the input shaft 100 is moved along the axial direction together with the input shaft 100.

[0092] The gear tooth 120 is formed as a single protruding portion that protrudes radially outward from the input shaft 10 at a predetermined position on the outer peripheral surface of the gear body 110. Specifically, the gear tooth 120 is formed in a semi-circular shape in a sectional view so as to fit into the gear groove portion 221 of the gear tooth 22 in order to mesh with or disengage from the gear tooth 22 of the wheel gear body 2 as the input shaft 10 rotates.

[0093] In particular, in the continuously variable transmission mechanism A4 of the present embodiment, at least one of the plurality of worm gear bodies 1, 1, 1, 1 arranged around the wheel gear body 2 rotates on the outer peripheral side and is always in mesh with the central wheel gear body 2, and is configured to always transmit the rotational power from the plurality of input shafts 100, 100, 100, 100 to the wheel gear body 2.

[0094] Specifically, as shown in FIGS. 14(a) to 15(d), the plurality of worm gear bodies 1, 1, 1, 1 are arranged around the wheel gear body 2 in the left, right, front, and rear directions with the protruding directions of the respective single gear teeth 120, 120, 120, 120 being the same in the axial view.

[0095] For example, as shown in FIGS. 14(a) and 15(a), when the gear tooth 120 of the rear worm gear body 1 is in mesh with the gear tooth 22 of the wheel gear body 2, the gear teeth 120, 120, 120 of the other front, left, and right worm gear bodies 1, 1, 1 are in a disengaged state.

[0096] That is, as the synchronous rotation of each worm gear body 1, 1, 1, 1 progresses, the rotational power is transmitted to the central wheel gear body 2 while sequentially engaging each worm gear body 1, 1, 1, 1 with the wheel gear body 2, such as the meshing state between the right worm gear body 1 and the wheel gear body 2 shown in FIGS. 14(b) and 15(b), the meshing state between the upper worm gear body 1 and the wheel gear body 2 shown in FIGS. 14(c) and 15(c), and the meshing state of the left worm gear body 1 shown in FIGS. 14(d) and 15(d), to continuously rotate the wheel gear body 2.

[0097] Due to the meshing position of the wheel gear body 2 with each worm gear body 1, 1, 1, 1, the rotational diameter of the wheel gear body 2 changes, so the gear ratio (rotation amount) also naturally changes, enabling variable deceleration and acceleration of the output shaft 20.

[0098] That is, as shown in FIGS. 13(a), 14(a) to 14(d), when each worm gear body 1, 1, 1, 1 is translated along each input shaft 100, 100, 100, 100 and positioned on the enlarged diameter side of the wheel gear body 2, the wheel gear body 2 that receives the rotational force from each worm gear body 1, 1, 1, 1 on the input side increases the rotational torque of the output shaft 20 and slows down the rotational speed.

[0099] On the other hand, as shown in FIGS. 13(b), 15(a) to 15(d), when each worm gear body 1, 1, 1, 1 is translated along each input shaft 100, 100, 100, 100 and positioned on the reduced diameter side of the wheel gear body 2, the wheel gear body 2 that receives the rotational force from each worm gear body 1, 1, 1, 1 on the input side decreases the rotational torque of the output shaft 20 and speeds up the rotational speed.

[0100] Thus, according to the continuously variable transmission mechanism A4 of this embodiment, along the taper shape of the wheel gear body 2, a plurality of worm gear bodies 1, 1, 1, 1 are movable, and according to the gear position on the circumferential surface of the wheel gear body 2 with which the worm gear bodies mesh, without using a device such as a special inverter, the rotational speed from the worm gear bodies 1, 1, 1, 1 can be continuously variable and the rotational power can be transmitted to the wheel gear body 2.

Explanation of Reference Numerals

[0101] A Continuously variable transmission mechanism 1 Worm gear body 10 Input shaft 11 Gear main body 12 Gear teeth 2 Wheel gear body 20 Output shaft 21 Gear main body 22 Gear teeth

Claims

【Claim 1】 It is composed of a longitudinal rod-shaped wheel gear body with gear teeth formed on its circumferential surface, and a worm gear body that meshes with the gear teeth on the circumferential surface of the wheel gear body. The wheel gear body is in a tapered shape with a diameter gradually increasing or decreasing from one end to the other end. The gear teeth are formed at a constant pitch in the circumferential direction of the wheel gear body. It has gear valley portions formed with tooth grooves provided in the gear teeth in a semi-circular shape in cross-section, while the pitch length is formed to be the same from one end to the other end of the wheel gear body. The worm gear body is such that the gear teeth on its circumferential surface mesh with the gear valley portions on the circumferential surface of the wheel gear body and is movable in the direction along the input shaft extending along the circumferential surface of the wheel gear body. While a plurality of the worm gear bodies are arranged around the wheel gear body, the gear teeth of the worm gear body are formed as a single semi-circular protrusion protruding radially outward of the diameter of the input shaft. The input shaft is provided in a manner inclined with respect to the axial direction of the wheel gear body. A continuously variable transmission mechanism, characterized in that the rotational speed from the worm gear body is continuously variable and transmitted to the wheel gear body according to the gear position on the circumferential surface of the wheel gear body with which the worm gear body meshes.

Images