JPH0424181B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an indexing device for a machine tool or an industrial machine, and more particularly to an indexing device for indexing a rotating body in a short time and without impact using constant speed rotation by an electric motor as power. Conventionally, mechanical indexing devices include Geneva mechanism,
And cam mechanisms are common. However, the Geneva mechanism has high angular velocity and angular acceleration, and the rate of change in angular acceleration is large, as shown in Figure 7, so it cannot be used in applications with large loads, and it tends to cause vibrations in the drive system. It also inherited its shortcomings.
Further, although the cam mechanism can obtain desired motion characteristics due to the shape of the cam, it is mechanically difficult to increase the size of the cam mechanism, and its use is limited to small machines. The present invention has been made in view of the above drawbacks, and
Transmitting rotation to the index gear via the planet gear, and swinging the planet gear with a swing arm,
Prevents sudden changes in acceleration and prevents starting and rotation during rotation indexing.
To provide a high-speed impactless indexing device that can smoothly stop, obtain a smooth acceleration curve, eliminate impact due to inertia, and enable high-speed indexing of heavy objects. In order to achieve the above object, the present invention is comprised of the following elements. That is, a base, a drive shaft rotatably provided on the base and having a drive gear fixed thereto, a driven gear rotatably provided on the base and meshing with the drive gear;
a swing arm that is swingably supported on the axis of the drive shaft and has a long groove formed in a radial direction at one end; a first swing arm that is rotatably provided at the other end of the swing arm and meshes with the drive gear; a second planetary gear formed on the same axis as the first planetary gear, and an indexing gear that rotates about the same axis as the drive shaft and meshes with the second planetary gear. an output shaft having the index gear fixed thereon and pivotally supported on the base on the same axis as the drive shaft; It is equipped with an engaging member that is slidably fitted into the long groove, and by changing the ratio of the number of meshing teeth between the driving gear and the first planetary gear, and between the second planetary gear and the indexing gear, the output to the drive shaft can be adjusted. An indexing device characterized by being able to set the number of indexes on a shaft to a predetermined number, and also preventing sudden changes in acceleration during indexing by planetary motion of planetary gears, eliminating shocks during indexing acceleration/deceleration. Consists of. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing an embodiment of the high-speed impactless indexing device of the present invention, and FIG. 2 is a cross-sectional view of the main part thereof taken along the line A-A. In these figures, the drive gear 1 is mounted on the base 13
The drive shaft (input shaft) 6 is connected to a drive shaft (input shaft) 6 rotatably provided. The drive shaft 6 is connected via a worm wheel 11 and a worm 12 to an electric motor with a brake (not shown), etc., and the drive gear 1
Rotate. A driven gear 5 connected to a driven shaft 15 is disposed below the driving gear 1, and is meshed with the driving gear 1 to rotate as a driven gear. On the other hand, a planetary gear 2 is disposed above the driving gear 1, and meshes with the moving gear 1 to perform planetary motion. A second planetary gear 3 is coaxially connected to the planetary gear 2 . An index gear 4 that meshes with the planetary gear 3 is connected to an output shaft 10 and is rotatably supported coaxially with the drive shaft 6. Further, in order to maintain the positional relationship between the driving gear 1 and the planetary gears 2 and 3, a holding member 14 is swingably attached to them. A clamp pin 7 is fitted in parallel to the axis of the driven shaft 15 at an eccentric position with a radius r of the driven gear 5, and an engagement member 9 is attached to this. The swinging arm 8, whose one end engages with the engaging member 9, is rotatably attached to the drive shaft 6 at its center, and has a long groove 8a extending in the radial direction at one end. The engaging member 9 is slidably engaged and held. The other end of the swing arm 8 is fixed to the connecting shaft of the planetary gears 2 and 3. In such a configuration, the planetary gears 2 and 3 are rotated by the rotational force of the drive gear 1, and the index gear 4 and the output shaft 10 to which it is connected are rotated.
At the same time, the driven gear 5 rotates, and the engagement member 9, which is provided at a position eccentric from the center of rotation, moves circularly. Since this engaging member 9 is engaged with the long groove 8a of the swing arm 8, the engaging member 9 slides in the long groove 8a along the longitudinal direction (radial direction of the arm 8), Swing arm 8
oscillate in the circumferential direction. The planetary gears 2 and 3 oscillate in response to this oscillation, and the indexing gear 4 and output shaft, which rotate in response to the rotation of the planetary gears 2 and 3, perform one stroke of inconstant velocity indexing motion. In this case, by changing the ratio of the number of teeth of each gear 1, 2, 3, 4, for one rotation of the drive shaft 6,
The number of indexes of the output shaft 10 can be changed. Here, the number of teeth of drive gear 1 is Z ₁ , the number of teeth of planetary gear 2 is Z ₂ , the number of teeth of planetary gear 3 is Z ₃ , and the number of teeth of index gear is
Z ₄ , the reduction ratio of the planetary gears 2 and 3 is J, and the index number is I, the number of teeth is expressed by the following formula. Z ₄ = Z ₁ I / J ... (1) Z ₂ = J (Z ₄ - Z ₁ ) / (J + I) ... (2) Z ₃ = Z ₂ / J ... (3) Index number I, The number of teeth Z ₁ and the reduction ratio J of the drive gear 1 are determined, and the number of teeth of each gear is calculated using equations (1), (2), and (3). Examples of the number of teeth are as follows.

[Table] Next, the indexing operation of the above embodiment will be explained in more detail with reference to FIGS. 2 to 6. In FIG. 2, the engagement member 9 on the driven gear 5
is assumed to start from the gear 1 side on the central axis gg. In this state, when the drive gear 1 is rotated at a constant angle W1 in the direction of the arrow, the swing arm 8 swings according to the rotation angle θ of the engagement member 9.
At this time, the planetary gears 2 and 3 rotate in accordance with the rotation of the drive gear 1, and move the index gear 4 with which they are meshed; It works in the opposite way. Here, with respect to the speed of the index gear 4 which is about to move according to the circumferential speed of the drive gear 1, this speed is calculated as The eccentric radius r of the crank pin 7 is determined so as to obtain an initial swing speed of the swing arm 8 that cancels out the deceleration speed of the crank pin 7. As a result, as shown in FIG. 5, the index gear 4 starts from a speed of 0, is gradually accelerated and increases in speed, and reaches Vmax when the rotation angle θ=π of the engagement member 9 is reached. After passing through θ=π, the index gear 4 is gradually decelerated and stops smoothly at θ=2π (the drive gear 1 rotates once). FIG. 5 shows the change in the angular displacement Y of the index gear at this time. A theoretical analysis of the above operation is as follows. That is, when calculating the eccentricity of the engaging member 9 for starting (1) 0 of the crank pin 7 provided at the eccentric position of the driven gear 5 according to FIG. 3, if the radius is r, the swing arm 8
The swing angle of is =tan ^-1 (λsinθ/1-λcosθ)...(1) However, λ=r/a The angular velocity _w2 of the swing arm 8 is _w2 = d/dt=λ(coosθ-λ) /1−2λcosθ+λ ²
×w ₁ ...(2) Axial center movement speed (initial speed) of planetary gears 2 and 3 v ₁
is, v ₁ = w ₂ ×b = λ(cosθ−λ)w ₁ /1−2λcosθ+λ ² b
...(3) The peripheral speed v ₀ of the drive gear 1 is v ₀ = π・D ₁・N ₁ = 30・D ₁・w ₁ (m/min)
...(4) If the relative peripheral speed of the planetary gear 2 due to planetary motion is v ₂ and the peripheral speed of the virtual gear 2', which is assumed to mesh with the outer periphery of the planetary gear 2, is v' ₂ , then the virtual gear 2 The zero starting condition for ' is v' ₂ = v ₀ - (v ₁ + v ₂ ), v' ₂ = 0
However, if the index gear 4 is decelerated or accelerated by the planetary gears 2 and 3, the index gear 4
In order for the vehicle to start and stop at 0, it is necessary to correct the deceleration or speed increase ratio. That is,
In order for the circumferential speed v ₄ of the index gear 4 to start at 0, the above-mentioned condition for v ₃ to start at 0 is corrected by the difference in deceleration of the planetary gear. The relationship shown in equation (5) is required. v ₀ - (1 + (J-1) / J) (v ₁ + v ₂ ) = 0 ... (5) Assuming v ₁ = v ₂ , from equations (3) and (4) (Figure 4) 30. D・w ₁ /60−(J+1)×λ(cosθ−λ)w ₁ /1
-2λcosθ+λ ² ×b=0 ...(6) Assuming θ=0, λ={2D+2(J+1)b-√{2D+2(J+1
)b} ² −4{D ₁ +2(J+1)b}×D/2{D+2
(J+1)b}...(7) r=a×λ...(8) Therefore, the eccentricity r of the crank pin for the peripheral speed v4 of the index gear ₄ to start at 0 is (7), (8 ) From formula λ={2D+2(J+1)b−√{2D+2(J+1
)b} ² −4{D ₁ +2(J+1)b}D/2{D+2(
J+1)b}a...(9) However, D ₁ is the pitch diameter of drive gear 1 (2) Indexing speed V is equivalent rotation speed of swing arm 8 N: N = 30w ₂ /
π The rotation speed N ₂ of the planetary gear shaft is N ₂ = (1 + Z ₁ / Z ₂ ) N - Z ₁ / Z ₂ N ₁ ... (10) However, N ₁ = 60 / T (rpm) T: Indexing time Planet The pitch radial peripheral speed V 3 of gear ₃ is v ₃ = π・D ₃・N ₂ /60 (m/sec) ...(11) The pitch radial peripheral speed V of index gear 4 is V = v ₁ + v ₃ = b・w ₁ (cosθ−λ)λ/1−2λcos
θ+λ ² +π・D3/60 {(Z ₁ + Z ₂ )N−Z ₁ N ₁ /Z ₂ }(m
/scc)...(12) Indexing angular velocity w ₄ of indexing gear 4 (Fig. 5 A) w ₄ =2V/D ₄ =2・b・w ₁ (cosθ−λ)λ/D ₄ (1− 2
λcosθ+λ ² )+π・t) _3/30・D ₄ {(Z ₁ +Z ₂ )N−Z
₁ N ₁ /Z ₂ }(rad/sec)...(13) (3) Indexing acceleration The indexing acceleration A of the pitch diameter of indexing gear 4 is A=dv/dt=dv ₁ /dθ・dθ/dt+dv ₃ /dθ・dθ/dt
=bw ₁ λ(-sinθ)(1- ^λ2 )/(1-2λcosθ+ ^λ2
) ²・w ₁ +D3(Z ₁ +Z ₂ )λ・w(−sinθ)×(1−λ ² )/
2Z ₂ (1−2λcosθ+λ ² ) ²・w ₁ =w ₁・λ・sinθ(1−
λ ² )/(1−2λcosθ+λ ² ) ² (b+D ₃ (Z ₁ +Z ₂ )/2Z ₂ )・w ₁ (m/sec ² )...
(14) The indexing angular acceleration x of the indexing gear 4 is (Fig. 6) x=2A/D ₄ (rad/sec ² ) ...(15) (4) The indexing displacement S of the indexing gear 4 is The displacement S of the pitch diameter of the index gear 4 has the following relationship from FIG. S=J・l+J・l ₁ +l ₂・(mm)...(16) However, if the movement is clockwise (+) and counterclockwise (-), the reduction ratio of planetary gears 2 and 3 is J. do. Now, when the planetary gears 2 and 3 are on the left side of the gg line, the index number is calculated by 40%, and the reduction ratio of the planetary gear is J=
If it is 1/2, S=1/2・θ/360・π・D1−1/2・ζ/360・π
・D1−bζ/180・π=π・D1/720(θ−4)−ζ/18
0・π・b (mm) ...(17) Angular displacement Y of index gear 4 (Figure 5 B) Y=S・180/π・1/R=360・S/π・D ₄ (degrees) (18) FIGS. 5 and 6 are examples of operating characteristic diagrams of the indexing device according to the present invention. As shown by the angular velocity curve and angular displacement curve in FIG. 5, it is clear that the index gear 4 starts smoothly, changes speed continuously without sudden speed changes, and stops smoothly.
As shown in Fig. 6, the acceleration is a modified sine curve with the highest acceleration at the rotation angle of 60° and 300° of the drive gear 1, and the angular acceleration curve is continuous with values of 0 at the start and end points. Therefore, it can be said that it has excellent properties against shock and vibration. FIG. 7 shows an operating characteristic diagram under the same conditions as the above-mentioned embodiment using a Geneva mechanism that has been widely used in the past. Since the Geneva mechanism performs indexing using a portion of the rotation angle of one rotation of the drive pin (90 degrees in the case of 4 indexing), the maximum speed and maximum acceleration are both considerably higher than that of this device, making it difficult to index. The angular acceleration at the starting point and ending point is 0.
Since the angular acceleration curve is not continuous, the angular acceleration curve becomes discontinuous and vibrations are likely to occur. On the other hand, the device of the present invention has a low maximum angular velocity and a low maximum angular acceleration as described above, and since the angular accelerations at the start point and end point of indexing are continuous at D, the impact at the start point and end point is small. As shown in FIG. 8, while the input shaft is continuously rotated, the output shaft can continuously move intermittently in a smooth S-curve shape. As explained above, the present invention has a configuration in which rotation is transmitted to the index gear via the planetary gear, and the planetary gear is oscillated by the swing arm, thereby suppressing sudden changes in acceleration and rotating the index gear. Starting and stopping at the time of departure are smooth, a smooth acceleration curve is obtained, and the impact caused by inertia is eliminated, making it possible to index heavy objects at high speed.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an embodiment of the high speed non-impact indexing device of the present invention, Fig. 2 is a sectional view of the main part thereof taken along the line A-A, Fig. 3 is a diagram explaining the speed of each part, and Fig. 4 is an indexing device. An explanatory diagram of displacement, Fig. 5 is a graph showing changes in angular velocity and displacement of the indexing gear, Fig. 6 is a graph showing changes in indexing acceleration of the indexing gear, and Fig. 7 is a graph showing changes in indexing acceleration of the indexing gear. It is a graph showing changes in indexing acceleration. FIG. 8 is a graph showing the relationship between the rotation of the input shaft and the rotation of the output shaft. 1... Drive gear, 2, 3... Planetary gear, 4...
Index gear, 5... Driven gear, 6... Drive shaft, 7...
... Crank pin, 8 ... Swing arm, 9 ... Engagement member, 10 ... Output shaft, 11 ... Worm wheel, 12 ... Worm, 13 ... Base, 14 ...
Holding member, 15...driven shaft.

Claims (1)

[Scope of Claims] 1. A base, a drive shaft rotatably provided on the base and having a drive gear fixed thereto, and a driven gear rotatably provided on the base and meshing with the drive gear. , a swinging arm pivotably supported on the drive shaft axis and having a long groove formed in a radial direction at one end; and a swinging arm rotatably provided at the other end of the swinging arm;
a first planetary gear that meshes with the drive gear; a second planetary gear formed on the same axis as the first planetary gear; and a second planetary gear that rotates about the same axis as the drive shaft. a gear, an index gear that meshes with the gear; an output shaft to which the index gear is fixedly mounted and pivoted on the base on the same axis as the drive shaft; and a position eccentric from the rotation axis of the driven gear. an engaging member provided in a protruding manner and slidably fitted into the long groove; By changing the number of indexes of the output shaft relative to the drive shaft, it is possible to set the number of indexes to a predetermined number, and the planetary motion of the planetary gear prevents sudden changes in acceleration during indexing, eliminating shock during indexing acceleration/deceleration. An indexing device characterized by: