JPH0828632A - Gear mechanism - Google Patents

Abstract

PURPOSE:To secure smooth meshing by forming involute curves or approximate curves from pitch angle intersections in an area of circumferences of tooth ends and tooth bottoms, for forming gear phases of an external gear and an internal gear, and thereby eliminating interference in the gear in case that tooth length and number of theeth are reduced. CONSTITUTION:Involute curves IC1, IC2 are alternatively prepared outward from a required toth bottom periphery drtheta in respect to each of pitch angle intersections PP1 to be supplied to required number of teeth. An intersection PP2 of both the curves serves as a temporary length of an external gear. An approximate line ICr is prepared in the vicinity of the intersection. An external gear G' having tooth length (h) which is 30 to 70% of the temporary length. The required number of teeth exceeds the number of teeth of the external gear. In an internal gear Gi, a required pitch angle is narrowed and the number of pitches are increased compared to those of the external gear. The internal gear Gi has a tooth end diameter and a toot bottom diameter obtained respectively by multiplying those of the external gear G'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combination of an internal gear and an external gear that does not impair transmission efficiency and can be expected to have a large reduction ratio. The present invention relates to a gear mechanism in which an eccentric rotation of an external gear, which is rotationally displaced only by the difference in the number of teeth, is extracted through a bellows mechanism for center rotation, and which combines an internal gear and an external gear used for a reduction gear.

[0002]

2. Description of the Related Art Generally, when meshing an internal gear and an external gear (pinion), if the number of teeth of the internal gear is small or the difference in the number of teeth of the internal gear and the external gear is small, it is impossible to assemble due to interference in the gear. Therefore, it is necessary to increase the difference between the number of teeth of the internal gear and the number of teeth of both gears. A gear mechanism that combines an internal gear and an external gear makes inward contact with the internal gear and meshes the external gear, the rotation directions of both gears are the same, and the space is saved.
A large speed ratio can be transmitted. In the conventional mechanism, a cup-shaped thin spring material called a harmonic gear is used to form an external gear by thickening only the edges, and the external gear is deformed by a cam with respect to the internal gear, and the meshing engagement position. Is sequentially moved to extract the center rotation from the cup-shaped bottom.

[0003]

In the prior art, the external gear is formed into a ring shape, and the outer peripheral side surface thereof is provided with a tooth profile of a required tooth phase, and the external gear is rotated by a cam drive so that the conventional solid gear is used. There was no speed reducer in which a ring-shaped external gear was meshed with an internal gear.

[0004]

The present invention has been made in view of this point, and has a low tooth height, a small difference in the number of teeth of an internal gear and an external gear, and a smooth internal gear and external gear. It is an object of the present invention to provide a gear mechanism capable of engaging with each other and contributing to an increase in a reduction ratio when the gear mechanism is used in a speed reducer. That is, the mechanism of the present invention alternately draws the involute curves IC1 and IC2 for forming the tooth profile outward from the desired tooth bottom circumference drθ from each of the pitch angles dθ ′ intersection points PP1 to be provided for the required number of teeth, and the pitch concerned. Within the extended range of the angle dθ ', the intersection point PP2 of the involute curve is the temporary tooth length of the external gear G', the approximate curve ICr near the front and rear of the intersection point PP2 of the involute curve is drawn, and the approximate curve ICr is the tooth phase, An external gear that is formed with a tooth height h of 30% to 70% of the height of the temporary tooth height while obtaining the center of the radius Gr of the tooth phase, and has a tooth circumference dKSθ and a tooth circumference drθ. In the range, an external gear G'formed by drawing the involute curves IC1, IC2 or the approximate curve ICr from each pitch angle intersection PP1 to form a tooth phase, and an internal gear meshingly engaged with the external gear G '. Gi The required number of teeth is greater than the number of teeth of the external gear, the pitch angle dθi of the internal gear Gi is narrow and the number is large compared to the angle and number of the pitch angle dθ ′ of the external gear G ′. A value obtained by dividing the angle of the gear pitch angle dθ ′ by the angle of the inner gear pitch angle dθi is taken as a multiple, and the value obtained by multiplying the root diameter dr of the external gear by the multiple is taken as the tip diameter dKi of the internal gear. A value obtained by multiplying the tip diameter dKS of the external gear G ′ by the multiple is set as the root diameter dri of the internal gear Gi, and within the range of the tip circumference dKiθ of the internal gear and the root circumference driθ, A combination of an internal gear Gi formed by forming an involute curve or an approximate curve from the pitch angle intersection point P6i on the tooth bottom circumference toward the tooth tip circumference dKiθ existing inside to form a tooth phase. To do.

[0005]

[Operation] By adopting the above-mentioned method, the external gear G'and the internal gear Gi have low tooth heights, and even if the difference in the number of teeth of both gears is reduced, there is no interference in the gears and smooth operation is achieved. The internal gear and the external gear can be meshed with each other, and when the cam gear is used for a speed reducer that drives the external gear, the reduction ratio can be increased.

[0006]

EXAMPLE The formation of the internal gear and the external gear of the present invention has a low tooth height, and even if the difference in the number of teeth of the internal gear and the external gear is reduced, a tooth phase without interference is formed. In a small module, the difference in the number of teeth between the two allows for one tooth. In the present description, one embodiment of the present invention is shown in which the present invention can smoothly rotate even if the number of teeth is such that it is easy to draw and does not mesh due to interference in the conventional tooth phase. The difference in the number of gear teeth is described as having four teeth. The external gear described has a root diameter of 75 mm, the number of teeth is 24, and the number of teeth of an internal gear that meshes with this is 28.

FIG. 1A is a development view of an external gear G'for calculating basic numerical values. The pitch angle dθ 'per tooth is 360 ° / 24 = 15 °, which is a value obtained by dividing the central angle by the total number of teeth. An intersection point PP1 of the tooth bottom circumference drθ and the pitch angle dθ ′
Draw the respective involute curves IC1 and IC2 from, and set the intersection point PP of both involute curves IC1 and IC2
2 is the tip diameter dKS in FIG. 1 (A). In order to obtain the approximate curve ICr of the involute curve IC1, from the intersection points P1 and P2 on the involute curve IC1 before and after the intersection point PP2 of the involute curve, respective radii r ₁ ,
r ′ ₁ and r ₂ , r ′ ₂ are drawn, and the respective intersection points P3 and P
3'is obtained, and a straight line rs connecting the intersection points P3 and P3 'and an approximate curve ICr approximate to the involute curve IC1 are obtained. The length of the approximate curve ICr to the radius center is the approximate radius Gr, and the involute curve IC1 or the approximate curve ICr shows the tooth phase Gf that determines the tooth shape.

The tooth height h is from the root circumference drθ to the tip circumference dKSθ. From the actual measurement from Fig. 1 (A), tooth height h
Is 11.5 mm and the approximate radius Gr is 32 mm. FIG.
In the case of the tooth height h of 11.5 mm in (A), since meshing with the corresponding internal gear is impossible due to interference, the external gear is set by this method to make this possible. 11.5 mm of the tooth height h according to FIG. 1 (A) is 11.5 mm × 0.6 = 6.
9 mm = 7 mm. As a result, the number of teeth is Z 24, the root diameter is dr 75 mm, the tip diameter is dK1 89 mm, the pitch angle is dθ 15 °, the approximate radius is Gr 32 mm, and the unknown is the pitch circle diameter dO.

The pitch circle diameter dO will be described below for extraction from the drawing. The case of forming the external gear G shown in FIG. 2 will be described in detail with reference to the enlarged view shown in FIG. The root radius dr / 2 of the external gear G is 75/2 = 37.5 mm, the tooth length h1 is 7 mm, the tip radius dK1 / 2 is the root radius dr / 2 + the tooth length h1 to 37.5 mm + 7 mm = 44.5 mm. is there.
As can be seen from FIG. 3, the tooth tip Gt has a pitch angle dθ0 (see FIG.
(Same as dθ 'in (A)), which is the half pitch angle dθ
Each straight line SS1 from the center SS passing through the contact point P7 of No. 1 and the intersection P6 group on the tooth tip circumference dK1θ indicate the position of the tooth tip Gt. The position showing the valley portion Gr1 of the tooth bottom is the pitch angle d.
This is the position of the group P5 of the intersection of the straight line SS0 of the boundary forming θ0 and the tooth root circumference dr1θ. The intersection points P6 and P5 are staggered on each of the tooth tip circumference dK1θ and the tooth bottom circumference dr1θ, and the intersection point P6 is at an approximate radius GrO (the same as Gr in FIG. 1A) 32 mm as shown in the figure. And the intersection point P5 is connected by an approximated curve GfO (the same as ICr in FIG. 1A). The approximate curve GfO is called a tooth phase.

Next, the pitch circle diameter dO will be determined. Circle pitch tO on pitch circle dOθ of external gear G
And the arc tooth thickness SO, it is necessary that 1/2 of the circular pitch tO be equal to the arc tooth thickness SO. This means that the circular arc tooth thickness SO and the circular arc non-tooth thickness SOn are equal, and the circular arc tooth thickness angle SOθ corresponding to the half pitch angle corresponding to this.
And the arc non-tooth thickness angle SOnθ are equal. Therefore, the pitch angle dθ2 (pitch angle dθ) which is half the arc tooth thickness angle SOθ occupied in dθ1 which is half the pitch angle dθ
0/4) and the pitch angle dθ2 (1/4 of the pitch angle dθ0), which is half the arc non-tooth thickness angle SOnθ, are equal, so from the center SS passing through the contact point P9 forming the boundary between the pitch angles dθ2. The position of the intersection P8 of the straight line SS2 with the approximate curve GfO is the pitch circle radius dO / 2 from the center SS. The measured value in the figure is 41.2 mm. Therefore, the pitch circle diameter dO is twice that, which is 82.4 mm. The numerical values of the respective parts of the external gear G are shown above.

The calculation of the numerical values of the respective parts forming the internal gear Gi shown in FIG. 4 will be described in detail with reference to the enlarged view of FIG. 1 (B). Since the number of teeth zi of the internal gear Gi has already been described as 28, the pitch angle dθi is 360 ° / 28 = 12.8571428.
It is 6 ° but 12.857 °. The tooth tip diameter dKi of the internal gear Gi corresponding to the tooth bottom diameter dr of the external gear G is a value obtained by multiplying the tooth bottom diameter dr of the external gear G by a multiple, and the multiple is the value of the pitch angle dθ0 of the external gear G. Is divided by the value of the pitch angle dθi of the internal gear Gi, and the multiple is 15 ° / 12.8.
57 ° = 1.167. Therefore, the tip diameter dKi is 7
It is 5 mm x 1.167 = 87.525 mm. The tip radius dKi / 2 is half that, 87.525 / 2 ≈ 44 mm
Is. The root diameter dri of the internal gear Gi corresponding to the tip diameter dK1 of the external gear G is a value obtained by multiplying the tip diameter dK1 by a multiple, which is 89 mm × 1.167 = 104 mm. The addendum radius dKi / 2 is 52 mm. Tooth tip Gti
Is the intersection point P5i of each boundary line SS0i of the pitch angle dθi and the tooth tip circumference dKiθ. Internal gear Gi
The position of the valley portion Gni is a straight line SS1i from the center SSi passing through the contact point P7i having a pitch angle dθi1 that is a half-pitch angle that divides the pitch angle dθi into two intersections P6i on the tooth circumference driθ. Intersection P5 on the tip circumference dKiθ
i and the intersection point P6i on the tooth circumference driθ are approximated by the radius Gr
i (same as Gr in FIG. 1 (A)) is drawn at 32 mm, and the approximated curve Gfi (same as ICr in FIG. 1 (A)) forms a connecting tooth phase.

On the pitch circumference dOiθ, the circle pitch tOi
And the circular arc tooth thickness SOi require that the value of 1/2 of the circular pitch tOi and the circular arc tooth thickness SOi be equal. Therefore, the value of the arc tooth thickness SOi and the value of the arc non-tooth thickness SOni are equal, and the corresponding arc tooth thickness angle SOiθ and arc non-tooth thickness angle SOniθ are equal. Arc tooth thickness angle S
Both Oiθ and arc non-tooth thickness angle SOniθ are pitch angles d
The angle is 1/2 of θi and is the same value as the pitch angle dθi1 which is 1/2 of the pitch angle dθi. From the above, the pitch angle dθi2 (1/4 of the pitch angle dθi), which is ½ of each arc tooth thickness angle SOiθ within the angular range of the pitch angle dθi1, which is ½ of the pitch angle dθi, and the arc non- The pitch angle dθi2 (1/4 of the pitch angle dθi), which is ½ of the tooth thickness angle SOniθ, is equal to the pitch angle d.
It passes through the boundary point P9i of the pitch angle dθi2 which is ¼ of θi,
A straight line SS from the center SSi that bisects the pitch angle dθi1
The position of the intersection P8i between 2i and the approximate curve Gfi (the same as ICr in FIG. 1A) is the pitch circle radius d from the center SSi.
It is Oi / 2. Pitch circle radius dOi / 2 is 4 measured
7 mm. Therefore, the pitch circle diameter dOi is 47 mm ×
2 = 94 mm.

Summarizing the numerical values of the above results, the internal gear Gi
Is the number of teeth zi 28 teeth tip diameter dKi 87.525 mm root diameter dri 104 mm pitch angle dθi 12.857 ° approximate radius Gr 32 mm pitch circle diameter dOi 94 mm. As described above, the pitch circle diameter dO of the external gear G is 82.4 mm, while the pitch circle diameter dO of the internal gear Gi is
Since i is 94 mm, the eccentricity VB of the center SS of the external gear G with respect to the center SSi of the internal gear Gi is 94 mm-82.4 mm.
/2=5.8 mm, and the state of meshing with the internal gear Gi and the external gear G is shown in FIGS. 5 and 6. As shown in FIG. 6, the tips are dropped to strengthen the tip of each tooth.

[0014]

As described above, according to the present invention, an involute curve or an approximate curve is drawn from each pitch angle boundary point in the range of the tip circumference and the root circumference to draw the external gear and the internal gear. By forming a tooth phase, the tooth height of both gears is low, there is no interference in the gears even if the difference in the number of teeth is reduced, and smooth meshing is possible, and a cam mechanism that drives the external gear A large reduction ratio can be obtained when used as a reduction gear for practical use.

[Brief description of drawings]

FIG. 1A and FIG. 1B are structural explanatory views of an external gear and an internal gear in one embodiment of the mechanism of the present invention.

FIG. 2 is a front view showing a tooth profile of the entire external gear according to the present invention.

FIG. 3 is an enlarged front view of a main part of FIG.

FIG. 4 is a front view showing the tooth profile of the entire internal gear according to the present invention.

FIG. 5 is a front view showing a meshing state of an external gear and an internal gear in the present invention.

FIG. 6 is a front view showing another example of the meshed state.

[Explanation of symbols]

dθ 'Pitch angle (external gear G') dθ Pitch angle (external gear G) dθ0 Pitch angle dθ1 Pitch angle (1/2 of dθ) dθ2 Pitch angle (1/4 of dθ0) dθi Pitch angle (internal gear Gi) dθi1 Pitch angle (1/2 of dθi) dθi2 Pitch angle (1/4 of dθi) IC1 Involute curve IC2 Involute curve ICr Approximate curve (tooth phase) Gfi Approximate curve (tooth phase) GfO Approximate curve (tooth phase) G ′ External gear G in outer gears Gi gear r ₁ radius r _'1 radius r ₂ the radius r' ₂ radius rs linear hi tooth height h tooth depth GrO approximate radius Gr approximate radius Gri approximate radius SS center SSi center Gf tooth phase Gni valley Gr1 valleys Gt tooth tip Gti tooth tip P1 to P3 intersection point P3 'intersection point PP1 intersection point PP2 intersection point P5 intersection point P6 intersection point P8 intersection point P5i intersection point P6i intersection point P8i Point P7i Boundary point P9i Boundary point P7 contact point P9 contact point dr Root diameter dri root diameter dKs Tip diameter dK1 Tip diameter dKi Tip diameter SS0 straight line SS1 straight line SS2 straight line SOn arc non-tooth thickness SOn arc pitch non-tooth thickness tO tOi circle pitch SO arc tooth thickness SOi arc tooth thickness dO pitch circle diameter dOi pitch circle diameter drθ tooth bottom circumference dr1θ tooth bottom circumference driθ tooth bottom circumference VB eccentricity dKSθ tooth tip circumference dK1θ tooth tip circumference dKiθ tooth circumference Circumference dOθ pitch circumference dOiθ pitch circumference

Claims (1)

[Claims] 1. An involute curve for forming a tooth profile is alternately drawn outward from each pitch angle intersection point to provide a required number of teeth from the circumference of the required tooth bottom, and the involute curve is extended within the extension range of the pitch angle. The temporary gear length of the external gear at the intersection of
Draw an approximate curve near the intersection of the involute curve, use the approximate curve as a tooth phase, obtain the radius center of the tooth phase, and obtain a tooth height h of 30% to 70% of the height of the temporary tooth height.
An external gear formed by forming an involute curve or an approximate curve from each pitch angle intersection point in the range of the tooth tip circumference and the tooth root circumference to form a tooth phase. , The internal gear meshingly engaged with this external gear, the required number of teeth is greater than the number of teeth of the external gear, and the pitch angle angle of the internal gear is narrower than the pitch angle angle and number of the external gear. The number should be increased, and the value obtained by dividing the pitch angle of the external gear by the pitch angle of the internal gear shall be a multiple, and the value obtained by multiplying the root diameter of the external gear by the multiple shall be the tip of the internal gear. In addition to the diameter, the value obtained by multiplying the tip diameter of the external gear by the multiple is taken as the root diameter of the internal gear, and within the range of the tip circumference of the internal gear and the root circumference, the root circle concerned The involute curve or approximate curve is drawn from the intersection of the pitch angles on the circumference toward the inner circumference of the tooth tip to form the tooth phase. Gear mechanism, characterized in that the internal gear combination composed.