JP2009150524A - Gear structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gear structure for optionally changing a shaft angle, making an engagement and transmission efficiency of a force excellent, and transmitting high torque force. <P>SOLUTION: The gear structure 1 where a projection gear 10 and a recess gear 20 are engaged employs the constitution where the pitch circle diameter of the projection gear 10 is formed so as to project to the outer peripheral side with a predetermined curvature and change in the thickness direction of the projection gear 10, and the pitch circle diameter of the recess gear 20 is formed so as to recess to the inner peripheral side with the same curvature as the predetermined curvature and change in the thickness direction of the recess gear 20. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a gear structure capable of changing the shaft angle of meshing gears.

  In general, it is known to use a bevel gear to mesh a gear train (gear structure) at a predetermined shaft angle. However, since the bevel gear is usually designed so that the gear does not mesh unless the shaft angle is constant, if a predetermined shaft angle is changed due to a design change or the like, another shaft having a shaft angle after the change is changed. There is a problem that a new bevel gear has to be used, and there is a need for a gear that can change the shaft angle to a desired angle.

Conventionally, as a gear whose shaft angle can be changed, a special gear having disc-shaped teeth provided at a predetermined radius from the center of the tip of the gear is used, and meshed with a spur gear, thereby enabling the shaft angle to be changed. A gear structure is known (see, for example, Patent Document 1 and Patent Document 2).
JP-A-5-123922 Japanese Patent Laid-Open No. 5-240312

  However, the gear described in the above patent document has a convex curved surface at the contact portion with the spur gear, and the spur gear does not have a curved surface corresponding to the special shape. There was a problem that power transmission efficiency was poor. Moreover, since the said gear has the said special tooth | gear, there existed concern that the intensity | strength was insufficient about whether it was the intensity | strength which can endure transmission of the force of high torque with a spur gear.

  The present invention has been made in view of the above problems, and provides a gear structure that can arbitrarily change the shaft angle, improve the meshing and force transmission efficiency, and can transmit a high torque force. The purpose is to do.

In order to solve the above-described problems, the present invention provides a gear structure in which a first gear and a second gear mesh with each other, and the diameter of the pitch circle of the first gear is the thickness direction of the first gear. And the diameter of the pitch circle of the second gear is the same as the predetermined curvature in the thickness direction of the second gear on the inner peripheral side. A configuration is adopted in which it is formed to be recessed and changed.
By adopting such a configuration, in the present invention, the first gear and the second gear form a predetermined curved shape in the thickness direction, and the axial angle along the curved shape can be changed, and Since the curved shape of the first gear and the curved shape of the second gear are formed corresponding to each other, the meshing and the force transmission can be made smooth.

In the present invention, a configuration is adopted in which the tooth thicknesses of the first gear and the second gear change in accordance with the position in the thickness direction.
By employ | adopting such a structure, in this invention, it can be set as the tooth shape corresponding to a curved shape by changing tooth thickness.

In the present invention, the tooth thickness of the first gear and the second gear is such that the dimensional ratio between the maximum tooth thickness and the minimum tooth thickness is the dimensional ratio between the maximum reference pitch circle diameter and the minimum reference pitch circle diameter. A configuration is adopted in which they are formed to be the same.
By adopting such a configuration, in the present invention, a tooth shape corresponding to a curved shape can be obtained by changing the tooth thickness based on the dimensional ratio of the reference pitch circle diameter.

In the present invention, the number of teeth of the first gear and the number of teeth of the second gear are each based on the curvature based on the reference number of teeth obtained by a predetermined relational expression between the module and the diameter of the pitch circle. A configuration in which it is formed to be reduced is adopted.
By adopting such a configuration, in the present invention, the number of teeth is decreased so as to correspond to the magnitude of the curvature, so that the interference between the teeth of the first gear and the teeth of the second gear when the shaft angle is changed is achieved. Can be prevented.

In the present invention, the number of teeth of the first gear and the number of teeth of the second gear are determined based on the reference number of teeth obtained from a predetermined relational expression between the module and the diameter of the pitch circle. A configuration is adopted in which the thickness is reduced based on at least one of the thickness and the thickness of the second gear.
By adopting such a configuration, in the present invention, the number of teeth is reduced so as to correspond to the thickness, thereby causing interference between the teeth of the first gear and the teeth of the second gear when the shaft angle is changed. Can be prevented.

In the present invention, the first gear and the second gear employ a configuration having straight teeth.
By adopting such a configuration, the present invention provides a gear structure that is easy to manufacture and low cost.

In the present invention, the first gear and the second gear employ a configuration having a helical.
By adopting such a configuration, the present invention provides a gear structure with high torque, high transmission efficiency, quietness and low vibration.

According to the present invention, the first gear and the second gear mesh with each other, and the diameter of the pitch circle of the first gear has a predetermined curvature on the outer peripheral side in the thickness direction of the first gear. And the diameter of the pitch circle of the second gear changes so as to be recessed toward the inner peripheral side with the same curvature as the predetermined curvature in the thickness direction of the second gear. By adopting the configuration of being formed, the first gear and the second gear form a predetermined curved shape in the thickness direction, the axial angle along the curved shape can be changed, and the first gear Since the curved shape of the gear and the curved shape of the second gear are formed correspondingly, meshing and transmission of force can be made smooth.
Therefore, according to the present invention, there is an effect that it is possible to provide a gear structure that can improve the meshing and force transmission efficiency and can transmit a high torque force.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size.

FIG. 1 is a perspective view showing a gear structure 1 in the present embodiment.
2 is a cross-sectional view taken along line XX in FIG. 1 of the gear structure 1 according to the present embodiment.
As shown in FIG. 1, the gear structure 1 includes a convex gear (first gear) 10 having a convex outer shape in the thickness direction, and a concave gear (second gear) having a concave shape in the thickness direction meshing with the convex gear. 20. Further, as shown in FIG. 2, the rotating shaft 11 extending in the thickness direction of the convex gear 10 and the rotating shaft 21 extending in the thickness direction of the concave gear 20 are arranged in parallel to each other. The distance between the centers of the gear 10 and the concave gear 20 is set to 60 mm.
In this embodiment, the convex gear 10 and the concave gear 20 are redesigned on the basis of a spur gear having a tooth thickness of 30 mm, a reference pitch circle diameter of 60 mm, a module of 2, and a number of teeth of 30. A specific shape according to the design change will be described below.

First, the shape of the convex gear 10 will be described with reference to FIGS. 3 and 4.
FIG. 3 is a sectional view in the thickness direction of the convex gear 10 in the present embodiment.
FIG. 4 is a cross-sectional view taken along the arrow A along the diameter P1 of the pitch circle of the teeth 15 of the convex gear 10 in the present embodiment.
The convex gear 10 protrudes to the outer peripheral side in the thickness direction with a predetermined curvature with the intersection point of the rotating shaft 11 and the horizontal line 12 that equally divides the thickness of the convex gear 10 in the thickness direction as a center point 13. The outer shape is formed. More specifically, the reference pitch circle diameter, the tip circle diameter, and the root circle diameter of the convex gear 10 similarly change so as to protrude with a predetermined curvature in the thickness direction around the center point 13. It becomes.

More specifically, this embodiment will be described as an example. In the thickness direction, the reference pitch circle diameter of the convex gear 10 is formed in an arc shape whose distance from the center point 13 is 30 mm, and the tooth tip circle diameter is Is formed in an arc shape having a distance of 32 mm from the center point 13, and is further formed in an arc shape having a distance from the center point 13 of 27.5 mm in the root circle diameter.
Therefore, taking the reference pitch circle diameter as an example, the curvature increases from the maximum reference pitch circle diameter at the central portion of the convex gear 10 in the thickness direction from 60 mm to the minimum reference pitch circle diameter at the end in the thickness direction of 51.962 mm. Will change based on.

In addition, since the design of the convex gear 10 is changed so as to change the reference pitch circle diameter in the thickness direction as described above, the interval between the adjacent teeth 15 and the teeth 15 is narrow at the end in the thickness direction. become. Therefore, as shown in FIG. 4, the teeth 15 of the convex gear 10 in the present embodiment are formed so that the tooth thickness swells in the central portion in accordance with the change in the reference pitch circle diameter, and sequentially toward the end portion. The tooth thickness is reduced. Specifically, the tooth 15 is designed based on the tooth thickness (3.14 mm) of the module 2 so that the maximum tooth thickness is 3.14 mm at the center and the minimum tooth thickness is 2.719 mm at the end. Has been.
The dimensional ratio between the maximum tooth thickness and the minimum tooth thickness is designed to be the same as the ratio between the maximum reference pitch circle diameter and the minimum reference pitch circle diameter.

On the other hand, the shape of the concave gear 20 will be described with reference to FIGS.
FIG. 5 is a cross-sectional view in the thickness direction of the concave gear 20 in the present embodiment.
FIG. 6 is a cross-sectional view taken along the arrow B along the diameter P2 of the pitch circle of the teeth 25 of the concave gear 20 in the present embodiment.
As shown in FIG. 5, the concave gear 20 has the same curvature as the predetermined curvature in which the reference pitch circle diameter of the convex gear 10 changes in the thickness direction, and the reference pitch circle diameter inward in the thickness direction. It is formed to be recessed and change. Specifically, the concave gear 20 is on a horizontal line 22 that passes through the rotary shaft 21 and equally divides the thickness of the concave gear 20 in the thickness direction, and is a distance of 60 mm from the rotary shaft 21 (specifically, the convex gear 10 A center point 23 is a point of the distance between the rotating shaft 21 and the center point 13 when the gear 20 and the concave gear 20 are engaged with each other, and an outer shape is formed with a predetermined curvature on the inner peripheral side in the thickness direction. More specifically, the diameter of the addendum circle and the diameter of the root circle of the concave gear 20 similarly change so as to be recessed toward the inner peripheral side with a predetermined curvature in the thickness direction around the center point 23.

More specifically, this embodiment will be described as an example. In the thickness direction, the reference pitch circle diameter of the concave gear 20 is formed in an arc shape with a distance of 30 mm from the center point 23, and the tooth tip circle diameter is Is formed in an arc shape with a distance of 28 mm from the center point 23, and further, in the root diameter, it is formed in an arc shape with a distance of 32.5 mm from the center point 23.
Therefore, taking the reference pitch circle diameter as an example, the curvature of the concave gear 20 from the minimum reference pitch circle diameter at the central portion in the thickness direction from 60 mm to the maximum reference pitch circle diameter at the end in the thickness direction of 68.038 mm. Will change based on.

  Further, since the concave gear 20 has been redesigned to change the reference pitch circle diameter as described above in the thickness direction, the teeth 25 adjacent to each other at the end in the thickness direction are opposite to the case of the convex gear 10. As shown in FIG. 6, the teeth 25 of the concave gear 20 are designed so that the tooth thickness gradually increases from the center to the end. Specifically, the tooth 25 has a minimum tooth thickness of 3.14 mm at the center portion and a maximum tooth thickness of 3.626 mm at the end portion based on the tooth thickness (3.14 mm) of the module 2. The design has been changed. The change in the tooth thickness of the tooth 25 corresponds to the change in the tooth thickness of the tooth 15, and the curvatures of the side surface 25 a of the tooth 25 and the side surface 15 a of the tooth 15 are the same as shown in FIGS. 4 and 6. Designed to be

  Further, the convex gear 10 and the concave gear 20 having the above-described configuration have a reference pitch circle diameter of 60 mm at the center, and if the module is set to 2, the number of teeth is 30 according to a predetermined relational expression. Usually, the convex gear 10 and the concave gear 20 have a special shape, but there is a case where tooth interference (impossibility of meshing) occurs when changing the shaft angle described below. Therefore, in order to prevent the interference of teeth when the shaft angle is changed, the convex gear 10 and the concave gear 20 of the present embodiment are reduced in the number of teeth from five to 30 from the reference number of teeth, each having 25 teeth. It is configured. Note that the reduction of 5 is a result of designing based on the 3D simulation of the gear structure 1 by sequentially reducing the number of teeth one by one and appropriately checking whether there is interference when changing the shaft angle. Furthermore, the tooth-shaped corners at the ends of the teeth 15 and 25 are cut out slightly larger than the chamfers to prevent interference when changing the shaft angle (see FIG. 1).

Next, the shaft angle change of the gear structure 1 including the convex gear 10 and the concave gear 20 having the above-described shape will be described with reference to FIGS. 7, 8, and 9.
FIG. 7 is a diagram for explaining the shaft angle change of the gear structure 1.
FIG. 8 is a cross-sectional view taken along line YY of the gear structure 1 shown in FIG.
FIG. 9 is a cross-sectional view taken along line ZZ of the gear structure 1 shown in FIG.
As shown in FIG. 7A or FIG. 7C, the gear structure 1 having the above-described configuration is shown in FIG. 7A or FIG. 7C from the state where the convex gear 10 and the concave gear 20 are arranged in parallel. In order to arbitrarily change the shaft angle between the convex gear 10 and the concave gear 20, when the concave gear 20 is moved in the thickness direction along the curved shape of the diameter P1 of the pitch circle in the thickness direction of the convex gear 10, The shaft angle is changed so that the concave gear 20 rotates around the axis extending in the direction perpendicular to the paper surface in FIG.
In the gear structure 1 in which the shaft angle is changed, the pitch circle diameter P1 of the convex gear 10 and the pitch circle diameter P2 of the concave gear 20 change with the same curvature. The meshing relationship between the convex gear 10 and the concave gear 20 can be maintained (see FIGS. 8 and 9).

Therefore, according to the above-described embodiment, the gear structure 1 in which the convex gear 10 and the concave gear 20 are engaged with each other, and the diameter P1 of the pitch circle of the convex gear 10 is the outer periphery in the thickness direction of the convex gear 10. The pitch circle diameter P2 of the concave gear 20 is recessed to the inner peripheral side with the same curvature as the predetermined curvature in the thickness direction of the concave gear 20. By adopting the configuration of being formed to change, the convex gear 10 and the concave gear 20 form a predetermined curved shape in the thickness direction, and the axial angle along the curved shape can be changed, And since the curved shape of the convex gear 10 and the curved shape of the concave gear 20 are formed correspondingly, meshing and transmission of force can be made smooth.
Therefore, in this embodiment, the shaft angle can be arbitrarily changed, the meshing and the force transmission efficiency can be improved, and the gear structure 1 capable of transmitting a high torque force can be provided. .

  In the present embodiment, the tooth thickness of the convex gear 10 and the concave gear 20 can be changed to a tooth shape corresponding to the curved shape by adopting a configuration in which the tooth thickness changes according to the position in the thickness direction. .

  In the present embodiment, the tooth thicknesses of the convex gear 10 and the concave gear 20 are the same as the dimensional ratio between the maximum reference pitch circle diameter and the minimum reference pitch circle diameter, respectively. By adopting the configuration of being formed so as to become, the tooth thickness can be changed based on the dimensional ratio of the reference pitch circle diameter, and the tooth shape corresponding to the curved shape can be formed.

  Moreover, in this embodiment, the convex gear 10 and the concave gear 20 employ | adopt the structure that it has a straight tooth, and manufacture is easy and low-cost gear structure 1 is obtained.

(Relationship between number of teeth reduction and curvature and thickness)
Hereinafter, the relationship between the number of reductions in the number of teeth in the gear structure and the curvature and thickness of the pitch circle diameter will be described with reference to FIGS. In addition, description of the part which has the same structure as this embodiment is omitted.
In the following description, the convex gear 10 and the concave gear 20 are designed to have the same reference pitch circle diameter, the number of teeth, and the thickness at the center. Further, in the figure, the center point 13 indicates the intersection of the rotating shaft 11 of the convex gear and the horizontal line 12 that equally divides the thickness of the convex gear and the concave gear in the thickness direction unless otherwise specified. .

(First design change example)
FIG. 10 is a perspective view showing the gear structure 1 in the first design modification example.
FIG. 11 is a cross-sectional view in the thickness direction of the gear structure 1 in the first design modification example.
As shown in FIG. 11, the gear structure 1 shown in FIG. 10 has a distance between the centers of the convex gear 10 and the concave gear 20 of 40 mm, a thickness of 20 mm, a module of 1, and a pitch circle diameter P1 (P2). It is an example in the case of designing so as to change at 20 mm (curvature 0.05) with the center point 13 as the center in the thickness direction. In the first design change example, the number of teeth is reduced to 14 to 26 with a reference number of teeth of 40.

(Second design change example)
FIG. 12 is a perspective view showing the gear structure 1 in the second design modification example.
FIG. 13 is a cross-sectional view in the thickness direction of the gear structure 1 in the second design modification example.
As shown in FIG. 13, the gear structure 1 shown in FIG. 12 has a center-to-center distance between the convex gear 10 and the concave gear 20 of 90 mm, a thickness of 20 mm, a module of 3, and a pitch circle diameter P1 (P2). It is an example in the case of designing so as to change at 45 mm (curvature 0.0222) with the center point 13 as the center in the thickness direction. In the second design change example, the number of teeth is 30 with no reference number of teeth and no reference number of teeth.

(Third design change example)
FIG. 14 is a perspective view showing the gear structure 1 in the third design change example.
FIG. 15 is a cross-sectional view in the thickness direction of the gear structure 1 in the third design modification example.
As shown in FIG. 15, the gear structure 1 of the third design modification example shows a case where the center point 13 is shifted from the position of the rotating shaft 11 by 25 mm so as to be close to the concave gear along the horizontal line 12.
In the gear structure 1 having such a configuration, the distance between the centers of the convex gear 10 and the concave gear 20 is 100 mm, the thickness is 30 mm, the module is 2, and the pitch circle diameter P1 (P2) is the center point in the thickness direction. This is an example in the case of designing to change at 25 mm (curvature 0.04) with 13 as the center. In the third design modification example, the number of teeth is reduced by 11 to 39, where the reference number of teeth is 50.

(4th design change example)
FIG. 16 is a perspective view showing the gear structure 1 in the fourth design modification example.
FIG. 17 is a cross-sectional view in the thickness direction of the gear structure 1 in the fourth design modification example.
As shown in FIG. 17, the gear structure 1 of the fourth design modification example shows a case where the center point 13 is shifted from the position of the rotary shaft 11 by 10 mm so as to be separated from the concave gear along the horizontal line 12.
In the gear structure 1 having such a configuration, the distance between the centers of the convex gear 10 and the concave gear 20 is 40 mm, the thicknesses are each 20 mm, the module is 1, and the pitch circle diameter P1 (P2) is the center point in the thickness direction. This is an example in the case of designing so as to change at 30 mm (curvature 0.0333) with 13 as the center. In the fourth design modification example, the number of teeth is 40, which is reduced by 4 from the reference number of teeth of 40.

(Fifth design change example)
FIG. 18 is a perspective view showing the gear structure 1 in the fifth design modification example.
FIG. 19 is a cross-sectional view in the thickness direction of the gear structure 1 in the fifth design modification example.
As shown in FIG. 19, the gear structure 1 of the fifth design modification example shows a case where the center point 13 is shifted by 5 mm so as to be close to the concave gear along the horizontal line 12.
In the gear structure 1 having such a configuration, the distance between the centers of the convex gear 10 and the concave gear 20 is 75 mm, the thicknesses are each 20 mm, the module is 3, and the pitch circle diameter P1 (P2) is the center point in the thickness direction. This is an example in the case of designing so as to change at 32.5 mm (curvature 0.0308) with 13 as the center. In the fifth design change example, the number of teeth is 25 with no reference number of teeth and no reduction in number.

  According to the above design change example, it is considered that the number of reductions in the number of teeth of the gear structure is caused by the curvature and thickness, and the relationship between the number of reductions in the number of teeth and the curvature and thickness is a graph shown in FIG. Can be expressed as As shown in FIG. 20, when the curvature increases, the number of reductions in the number of teeth increases accordingly, and when the thickness increases, the number of reductions in the number of teeth tends to increase. Therefore, if the gear structure has a small curvature and thickness, it can be manufactured without reducing the number of teeth from the reference number of teeth, so that the fear of a decrease in strength, rigidity, etc. due to a design change can be avoided.

  Therefore, in the present embodiment, the number of teeth of the convex gear 10 and the number of teeth of the concave gear 20 are respectively reduced based on the above curvature from the reference number of teeth obtained by a predetermined relational expression between the module and the diameter of the pitch circle. In the gear structure 1, the tooth 15 of the convex gear 10 and the concave gear 20 when the shaft angle is changed are reduced by reducing the number of teeth so as to correspond to the magnitude of the curvature. Interference with the teeth 25 can be prevented.

  Further, in the present embodiment, the number of teeth of the convex gear 10 and the number of teeth of the concave gear 20 are the thicknesses of the convex gear 10 based on the reference number of teeth obtained from a predetermined relational expression between the module and the diameter of the pitch circle. In the gear structure 1, the number of teeth is set so as to correspond to the thickness of the convex gear 10 and the thickness of the concave gear 20 by adopting a configuration in which the thickness is reduced based on the thickness of the concave gear 20. By reducing, interference between the teeth 15 of the convex gear 10 and the teeth 25 of the concave gear 20 can be prevented.

  As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  For example, in the above-described embodiment, the convex gear 10 and the concave gear 20 have been described as having the same reference pitch circle diameter, number of teeth, and thickness at the center, but the present invention is limited to this configuration. Instead, the reference pitch circle diameter, the number of teeth, and the thickness at the center may be different.

Further, for example, in the present embodiment, the gear structure 1 has been described as having straight teeth because the design is changed based on the spur gear. However, the present invention is not limited to the above configuration, and can be applied to, for example, a gear structure of a helical gear (see FIGS. 21 and 22).
By adopting such a configuration, it is possible to obtain a gear structure with high torque, which is a characteristic of a helical gear, high transmission efficiency, quietness and low vibration.

FIG. 21 is a perspective view showing the helical gear structure 101, and FIG. 22 is a perspective view when the shaft angle of the helical gear structure 101 is changed.
As shown in FIGS. 21 and 22, the helical gear structure 101 has a helical gear 110 having a helical shape and a convex outer shape in the thickness direction, and a helical gear meshing with the convex gear. A concave gear 120 having a concave outer profile is formed. In the helical gear structure 101, the distance between the centers of the convex gear 110 and the concave gear 120 is 55 mm, the thickness is 24 mm, the module is 2, the number of teeth is seven, and the reference number of teeth is 25. It is 18 sheets. The convex gear 110 and the concave gear 120 are designed to have the same reference pitch circle diameter, number of teeth, and thickness at the center.

It is a perspective view which shows the gear structure in embodiment of this invention. FIG. 2 is a cross-sectional view taken along line XX in FIG. 1 of the gear structure in the embodiment of the present invention. It is sectional drawing in the thickness direction of the convex gear in embodiment of this invention. It is arrow A sectional drawing along diameter P1 of the pitch circle of the tooth | gear which the convex gear in embodiment of this invention has. It is sectional drawing in the thickness direction of the concave gear in embodiment of this invention. It is arrow B sectional drawing along the diameter P2 of the pitch circle of the tooth | gear which the concave gear in embodiment of this invention has. It is a figure explaining the shaft angle change of the gear structure in embodiment of this invention. FIG. 8 is a YY sectional view of the gear structure shown in FIG. 7B according to the embodiment of the present invention. FIG. 8 is a cross-sectional ZZ sectional view of the gear structure shown in FIG. 7B in the embodiment of the present invention. It is a perspective view which shows the gear structure in the 1st design change example in embodiment of this invention. It is sectional drawing in the thickness direction of the gear structure in the 1st design change example in embodiment of this invention. It is a perspective view which shows the gear structure in the 2nd design change example in embodiment of this invention. It is sectional drawing in the thickness direction of the gear structure in the 2nd design change example in embodiment of this invention. It is a perspective view which shows the gear structure in the 3rd design change example in embodiment of this invention. It is sectional drawing in the thickness direction of the gear structure in the 3rd design change example in embodiment of this invention. It is a perspective view which shows the gear structure in the 4th design change example in embodiment of this invention. It is sectional drawing in the thickness direction of the gear structure in the 4th design change example in embodiment of this invention. It is a perspective view which shows the gear structure in the 5th design change example in embodiment of this invention. It is sectional drawing in the thickness direction of the gear structure in the 5th design change example in embodiment of this invention. It is a figure which shows the relationship between the number of teeth reduction, curvature, and thickness in embodiment of this invention. It is a perspective view which shows the helical gear structure in embodiment of this invention. It is a perspective view at the time of the shaft angle change of the helical gear structure in embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Gear structure, 10 ... Convex gear (1st gear), 20 ... Concave gear (2nd gear), P1, P2 ... Diameter of pitch circle

Claims (7)

A gear structure in which the first gear and the second gear mesh,
The diameter of the pitch circle of the first gear is formed to protrude and change with a predetermined curvature toward the outer peripheral side in the thickness direction of the first gear, and the diameter of the pitch circle of the second gear is changed to the first gear. 2. A gear structure characterized in that it is formed so as to be concave and change in the inner peripheral side with the same curvature as the predetermined curvature in the thickness direction of the two gears.   2. The gear structure according to claim 1, wherein tooth thicknesses of the first gear and the second gear change according to positions in a thickness direction.   The tooth thicknesses of the first gear and the second gear are formed such that the dimensional ratio between the maximum tooth thickness and the minimum tooth thickness is the same as the dimensional ratio between the maximum reference pitch circle diameter and the minimum reference pitch circle diameter. The gear structure according to claim 2, wherein:   The number of teeth of the first gear and the number of teeth of the second gear are respectively formed by decreasing from the reference number of teeth obtained by a predetermined relational expression between the module and the diameter of the pitch circle based on the curvature. The gear structure as described in any one of Claims 1-3 characterized by the above-mentioned.   The number of teeth of the first gear and the number of teeth of the second gear are respectively determined from the reference number of teeth obtained by a predetermined relational expression between the module and the diameter of the pitch circle, and the thickness of the first gear and the second gear. The gear structure according to any one of claims 1 to 4, wherein the gear structure is formed to be reduced based on at least one of the thicknesses of the gears.   The gear structure according to claim 1, wherein the first gear and the second gear have straight teeth.   The gear structure according to claim 1, wherein the first gear and the second gear have a helical shape.

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