JP4884315B2 - Oscillating gear unit - Google Patents

Description

  According to the present invention, a first gear having n1 teeth fixed to a housing and a fourth gear having n4 teeth attached to an output shaft are arranged with their respective axis centers aligned with the input shaft, and the number of teeth A rotating body integrally provided with a second gear with n2 and a third gear with n3 teeth is provided at the inclined portion of the input shaft so that the second gear meshes with the first gear and the third gear meshes with the fourth gear. A point where the center point of the common sphere passing through the pitch circles of the first and second gears and the center point of the common sphere passing through the pitch circles of the third and fourth gears coincides with the origin. The axis of the input shaft is arranged on the X axis of the XY coordinates to be used, and the meshing points of the first and second gears and the meshing points of the fourth and third gears are the same quadrant or different quadrants of the XY coordinates. The present invention relates to a rocking gear device placed on top.

  Conventionally, the principle of a reduction gear device using a so-called oscillating gear device for oscillating motion has been known. This oscillating gear device can obtain a large reduction ratio with only four gears, and has various advantages. However, the oscillating gear device needs to have a spherical involute tooth profile that is difficult to produce with high accuracy and low cost, and has not been put into practical use. Instead of this spherical involute tooth profile, the present inventor changed the tooth profile of one of the gears to a so-called contour tooth having the same tooth thickness and tooth depth in the tooth direction, and the other tooth profile was created and transferred to the tooth profile of the contour tooth. Furthermore, the swing-type gear device can be put to practical use by using the contoured teeth and roller-shaped rollers as convex teeth. The details of the oscillating gear device are disclosed in Japanese Patent Publication No. 7-56324 (Patent Document 1).

  FIG. 10 shows a cross section of the main part of the oscillating gear device by the present inventor. In the oscillating gear device, the input shaft 1 and the output shaft 2 are connected by first to fourth gears A1 to A4, and the speed is reduced by these gears. The first to fourth gears A1 to A4 are bevel gears. The first gear A1 is fixed integrally to the housing 6. The second gear A2 and the third gear A3 are provided on one rotating body 3, and the rotating body 3 is rotatably supported by the inclined portion 1a of the input shaft 1. When the rotating body 3 is supported in an inclined manner as described above, a swinging motion can be generated in the rotating body 3 as the input shaft 1 rotates. In addition, a roller 4a is interposed in the meshing portion of each gear, and meshing friction is absorbed by the rolling of this roller.

As shown in FIG. 11, the roller 4a is rotatably supported by a concave groove 4b formed in the first gear A1 (fourth gear A4). And the semicylindrical convex tooth | gear 4 is formed with the roller 4a which protrudes from the ditch | groove 4b. Further, the second gear A2 (third gear A3) is also formed with a semicircular arc-shaped groove and formed as a concave tooth 5. When the rotating body 3 swings in the direction indicated by the arrow B, the second gear A2 (third gear A3) moves in the direction indicated by the arrow C, and the concave teeth 5 and the convex teeth 4 are moved. Engage with each other. At this time, the sliding generated between the concave teeth and the convex teeth is absorbed by the rolling of the rollers 4a.
Japanese Examined Patent Publication No. 7-56324

  In the above-mentioned oscillating gear device, the convex teeth are composed of concave grooves and rollers, that is, by interposing the rollers in the meshing portion, the frictional resistance of the meshing portion is reduced in principle. It becomes possible to increase the transmission efficiency. However, securing the meshing accuracy becomes a major issue due to the increase in the components of the meshing portion. If it is meshing of integral convex teeth and concave teeth, it is sufficient to ensure the accuracy of each of the two parts and the positioning accuracy between the two, but by increasing the roller as the meshing component, the individual precision of the three parts is increased. In addition, ensuring the positioning accuracy among the three parties becomes extremely complicated.

  In this type of oscillating gear device, the meshing of the first gear A1 to the fourth gear A4 causes the second gear A2 and the third gear A3 to run out of motion relative to the first gear A1 and the fourth gear A4. Since the meshing is carried out while the meshing is started and the meshing is disengaged, the generatrix of each gear will cross each other, and if the convex and concave teeth are formed in a simple linear shape, they mesh with each other. An interference part is generated and the meshing gear is not established. Therefore, both convex teeth and concave teeth cannot be made into simple shapes, one is made into a contoured tooth with a simple shape, and the other tooth form is created and transferred using a creation machine. By using the generated tooth profile, proper meshing without interference can be obtained.

  However, since the concave tooth as the generating tooth has a very complicated shape, it is necessary to position the concave tooth not only in the rotational direction but also in the tooth line direction. This is not only complicated, but also more complicated. In order to obtain a high positioning accuracy, it is possible to some extent by using a complicated assembly jig or performing a complicated operation, but there is a limit in considering productivity. Therefore, even if there is some variation in positioning accuracy, it may be possible to remove the interference portion by performing individual fitting for each combination gear prior to final assembly so that proper meshing accuracy can be obtained. This method not only increases the number of extra processing steps, but also has a problem in productivity because it requires the use of a special generating machine, particularly when the generating teeth are used.

  Therefore, in order to solve such problems, the support rigidity of the rollers in the rotation direction of the rollers constituting the convex teeth is increased, and the hardness of the rollers is made higher than the hardness of the concave teeth, so that Although it is conceivable to promote initial conformation of the concave teeth by the teeth, this method is not a sufficient solution.

  That is, according to this method, there is no need for special work such as running-in before assembling. However, until the initial running-in is completed, an abnormal hit occurs and it is difficult to generate noise. In order to shorten the conforming time, it is necessary to lower the hardness of the concave teeth so as to be more easily worn. However, if it is too low, the durability of the concave teeth will be affected. There is a contradictory property between shortening the fitting time and maintaining durability, and it is difficult to achieve both.

  The present invention has been made in view of the above points, and an oscillating gear device that ensures both the durability of the meshing teeth and the meshing accuracy, and has a high degree of freedom in machining accuracy and positioning accuracy. Its purpose is to provide.

According to a first aspect of the present invention for solving the above-mentioned problems, a first gear having n1 teeth fixed to the housing and a fourth gear having n4 teeth attached to the output shaft are connected to the input shaft. And the second gear meshes with the first gear, and the third gear rotates with the rotating gear integrally provided with the second gear having the number of teeth n2 and the third gear having the number of teeth n3. A center point of a common spherical surface that passes through the pitch circles of the first and second gears and is supported by the inclined portion of the input shaft so as to mesh with the fourth gear, and the pitch circles of the third and fourth gears. The axis of the input shaft is arranged on the X axis of the XY coordinates with the origin coincident with the center point of the common spherical surface that passes through, and the meshing point of the first and second gears and the fourth and third gears And the meshing point of the oscillating gear device in the same or different quadrants of the XY coordinates,
The first to fourth gears are configured as bevel gears,
Of the first to fourth gears, the first gear and the fourth gear have a semicircular groove having a semicircular cross section extending radially from the gear center at equal intervals on the pitch cone, and can freely roll into the groove. The second and third gears, which are configured as convex teeth as contour teeth with the arranged cylindrical rollers and mesh with the first gear and the fourth gear, respectively, have a predetermined arc shape that meshes with the convex teeth. Configured as concave teeth,
The convex teeth are set such that the tooth length is longer than the tooth length of the concave teeth,
The concave groove that constitutes the convex teeth has an enlarged portion whose opening expands toward the end of the tooth-pitch direction with the reference pitch circle diameter as a base point so that the rollers allow tilting in the circumferential direction within the concave groove. Is formed.

  By configuring as described above, even if there is a slight deviation in the assembly accuracy of each gear, in the meshing process between the convex teeth and the concave teeth, the rollers start from the reference pitch circle in the concave groove, and the concave teeth By tilting in accordance with the position of the tooth tip, the meshing with the concave teeth becomes appropriate, and the occurrence of local abnormal surface pressure is suppressed. Therefore, the degree of freedom of processing accuracy and positioning accuracy is increased, and productivity can be improved without impairing the durability of the meshing teeth.

  In addition, the shape of the concave grooves constituting the convex teeth can be the same shape as the concave teeth for generating and transferring the convex teeth, so that it can be processed by the same processing means, and productivity is increased. Especially improved. In particular, when using the processing means disclosed in Japanese Patent Laid-Open No. 10-235519 as a processing means for generating and transferring a concave tooth as a generating tooth, continuous processing is performed while swinging the workpiece using a so-called oscillating gear mechanism. Compared with the processing using the indexing means, the processing speed can be extremely increased and the error between pitches can be minimized.

  According to a second aspect of the present invention, in the first aspect, a reference pitch circle diameter of the convex teeth and the concave teeth is set at substantially the center of the streak direction, and the enlarged portion of the concave groove constituting the convex teeth is The opening is formed in a drum shape that expands outward in the tooth trace direction and inward in the tooth trace direction across the reference pitch circle diameter. With this configuration, the enlarged width of the enlarged portion can be minimized with respect to the angle error with the concave tooth, so that the engagement accuracy with the concave tooth is ensured and the positioning stability in the concave groove of the roller is ensured. It is possible to achieve compatibility with

  According to a third aspect of the present invention, in the first aspect of the present invention, the concave groove of the convex tooth is a generating tooth profile or an approximate generating tooth profile obtained by creating and transferring a convex tooth in the same manner as the concave tooth. By configuring in this way, processing with exactly the same production means becomes possible, and productivity is improved.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the hardness of the rollers constituting the convex teeth is set higher than the hardness of the concave teeth. By comprising in this way, it becomes possible to make small the expansion width of the expansion part of a ditch | groove by the improvement of initial conformity, and can improve the positioning stability in the ditch | groove of a roller more.

  The present invention can provide an oscillating gear device that ensures both the durability of the meshing teeth and the meshing accuracy, and has a high degree of freedom in processing accuracy and positioning accuracy.

  Embodiments of the present invention will be described below with reference to FIGS. The same or corresponding parts as those in the conventional example are given the same reference numerals, and detailed description thereof is omitted.

  First, prior to the description of the embodiments according to the present invention, the basic structure and basic principle of the oscillating gear device will be additionally described. The oscillating gear device shown in the figure includes a first gear A1 having n1 teeth fixed to a housing 6 and a fourth gear A4 having n4 teeth attached to an output shaft 2 and each input shaft 1. The rotating body 3 is arranged in such a manner that the shaft center is aligned and the second gear A2 having the number of teeth n2 and the third gear A3 having the number of teeth n3 are integrally provided. The second gear A2 meshes with the first gear A1, and the third gear A center point of a common spherical surface that is supported by the inclined portion 1a of the input shaft 1 so that the gear A3 meshes with the fourth gear A4 and passes through the pitch circles of the first and second gears, and the third and fourth The axis G of the input shaft is arranged on the X axis of the XY coordinates with the origin O as a point where the center points of the common spherical surfaces passing through the pitch circles of the gears coincide with each other, and the input shaft is inclined at a predetermined angle from the origin O. The axis H of the inclined portion 1a is disposed on the shaft, and the meshing points of the first and second gears and the meshing points of the fourth and third gears Are placed in the same quadrant or different quadrants of the XY coordinates.

  More specifically, the oscillating gear device has first to fourth gears A1 to A4 as four conical bevel gears set to the number of teeth corresponding to the reduction ratio, and the first gear and the second gear. It is composed of two gear pairs, a gear pair of gears and a gear pair of third gear and fourth gear. A predetermined reduction ratio is obtained by giving a predetermined difference in the number of teeth to each of the two sets of gear pairs. Of these, the first gear A1 is a fixed gear that is integrally fixed to the housing 6 and does not rotate. The second gear A 2 and the third gear A 3 are formed on the rotating body 3 that is supported by the inclined portion 1 a of the input shaft 1. The fourth gear A4 is provided on the output shaft 2.

  The rotating body 3 is supported by an inclined portion 1 a having an axis H that forms a predetermined angle with respect to the axis G of the input shaft 1. This inclination angle is set to be an eccentric amount corresponding to the difference in the number of teeth between the gears of the meshing gear pair, that is, the difference in the reference pitch circle diameter.

  Therefore, when the input shaft 1 rotates, the inclined portion 1a moves such that the head swings, and the rotating body 3 pivotally supported by the inclined portion 1a performs a swinging motion. As the rotator 3 swings, the second gear A2 is engaged with the first gear A1, and the third gear A3 is engaged with the fourth gear A4. Then, the second gear A2 rotates with respect to the first gear A1 by an amount corresponding to the difference in the number of teeth from the first gear A1 per one cycle of swinging motion (one rotation of the input shaft 1). That is, a one-stage reduction is performed between the first gear A1 and the second gear A2. Further, if a difference in the number of teeth is given between the third gear and the fourth gear, the same speed reduction action is performed during this time, and two-stage speed reduction is performed.

In this case, the final reduction ratio is determined by the difference in the number of teeth of the two sets of gear pairs. In other words, if the reduction ratio is R (the rotational speed of the output shaft 2 when the input shaft 1 makes one revolution),
R = 1− (n1 × n3) / (n2 × n4) (i)
It can be expressed as.

  Here, n1: number of teeth of the first gear A1, n2: number of teeth of the second gear A2, n3: number of teeth of the third gear A3, n4: number of teeth of the fourth gear A4, n1 = 99, n2 = When 100, n3 = 101, and n4 = 100, the reduction ratio R = 1/10000. If n1 = 9, n2 = 10, n3 = 11, and n4 = 10, the reduction ratio R = 1/100. In this way, by setting the number of teeth of the four gears arbitrarily, a wide reduction ratio from high speed reduction to reduction speed can be obtained.

  As described above, when the difference between the number of teeth of the first gear A1 and the number of teeth of the second gear A2 is 1, when the oscillating motion advances by one cycle, the distance between the first gear A1 and the second gear A2 Thus, the teeth that mesh are shifted by one. Further, when the difference in the number of teeth is 2, when the oscillating motion advances by one cycle, the meshing teeth are shifted between the first gear A1 and the second gear A2. Similarly, when the difference in the number of teeth is n, the meshing teeth are shifted by n. This also applies to the relationship between the third and fourth gears A3 and A4. The embodiment shown in FIG. 1 shows an embodiment of one-stage reduction in which the difference in the number of teeth is given only between the first and second gears and the difference in the number of teeth is zero between the third and fourth gears.

  The speed reduction ratio of the oscillating gear device can obtain a wide speed reduction ratio from a high speed reduction to a reduction speed, as is clear from the above description. In particular, when obtaining a reduction speed ratio, the reference pitch circle between the meshing gears. The difference in diameter becomes large, and it is necessary to increase the inclination angle of the inclined portion corresponding to this difference. This increases the amplitude of the oscillating motion of the rotating body, which is disadvantageous in terms of vibration.

Although this vibration can be reduced by providing a balancer, a new problem arises that the structure becomes complicated and the cost increases. Therefore, in the embodiment according to the present invention, a gear number difference is given to the gear pair of the first gear A1 and the second gear A2 of the two gear pairs, and the gear pair of the third gear A3 and the fourth gear A4. A predetermined reduction ratio is obtained by setting the difference in the number of teeth on the side to zero. As an example, the number of teeth n1 to n4 of the first to fourth gears,
By setting n1 = 99, n2 = 100, n3 = 100, and n4 = 100, the reduction ratio R becomes R = 1/100 according to the equation (i), and the same reduction ratio as the above-described reduction speed example is obtained. It is done.

  As described above, the single pitch reduction of only the gear pair composed of the first gear A1 and the second gear A2 makes the reference pitch circle diameter larger than that of the above-described two-step reduction example, but the reference pitch circle diameter. Thus, the same reduction ratio can be obtained with a small inclination angle. Thus, by reducing the inclination angle, not only the vibration can be reduced, but also the distance between the first gear and the fourth gear can be shortened and the tooth profile of the third gear can be simplified.

  Furthermore, in the case of one-stage reduction only on the side of the gear pair consisting of the first gear and the second gear, the third gear and the fourth gear do not affect the reduction ratio as long as they have the same number of teeth, and are arbitrary. Can be set. Therefore, by setting the number of teeth of the third gear A3 and the fourth gear A4 to be the same as the number of teeth of either the first gear A1 or the second gear A2, the teeth of three gears out of the four gears. The number can be made the same, greatly contributing to the improvement of processing efficiency, that is, production efficiency.

  In this case, the number of teeth of the third gear A3 and the fourth gear may be the same as the number of teeth of the second gear or the number of teeth of the first gear, but in the former case, the second gear A2, the third gear. By making the number of teeth of the gear A3 the same, the circumferential phase of the second gear and the third gear can be matched, so that the meshing position of the first gear A1 and the second gear A2 and the third gear A3 , The phase of the meshing position of the fourth gear A4 can be matched, and the axial load acting on the rotating body acts at the same timing, and the vibration of the rotating body can be minimized.

  In the latter case, it is particularly advantageous in improving processing efficiency. That is, when the first gear and the second gear are provided with a difference in the number of teeth and one-stage reduction is performed, only the second gear of the four gears is different from the first gear A1, the third gear. Since the shapes of the remaining three gears of the gear A3 and the fourth gear A4 can be made common, common machining with the same machining facility becomes possible.

  Next, a method for obtaining the tooth profile of the oscillating gear device will be described below. Here, FIG. 3 is a development view showing a method for obtaining the tooth profile of each bevel gear of the swinging gear device shown in FIG. 1, and FIG. Each gear A1, A2, A3, A4 is schematically shown as a pitch cone.

  Here, a common spherical surface Cir1 passing through the pitch circles of the first gear A1 and the second gear A2 and a common spherical surface Cir2 passing through the pitch circles of the third gear A3 and the fourth gear A4 are considered. Then, the center points of the respective common spherical surfaces are made coincident with each other, and the coincidence point is set as the origin O. Further, XY coordinates with the origin O as the origin are considered. The axis G of the input shaft 1 is arranged on the X axis of the XY coordinates. Further, the meshing point of the first and second gears A1 and A2 is C1, and the meshing point of the third and fourth gears A3 and A4 is C2. Then, the meshing points C1, C2 are placed in the first quadrant and the third quadrant or the second quadrant and the fourth quadrant.

The angle formed between the axis G of the input shaft 1 and the axis H of the inclined portion 1a is θ, the angle formed between the back cone of the first gear A1 and the center line of the pitch cone is θ ₁ , and the second gear A2 If the angle formed by the back cone and the center line of the pitch cone is θ ₂ , θ ₁ + θ ₂ = θ. It is also possible to make either one of the angles θ ₁ and θ ₂ zero, and in this case, the gear having the zero angle becomes the crown gear. Similarly, the third angle formed by the fourth gear A3, back cone and the center line of each pitch cone of A4, the third gear A3 is theta _3, the fourth gear A4 theta ₄ cutlet theta ₃ + theta ₄ = θ.

The number of teeth of the first to fourth gears is n1, n2, n3, and n4, respectively. Here, the distances D1D2, D2O2, D3O3, D4O4 from the vertices O1, O2, O3, O4 of the pitch cones of the first to fourth gears A1-A4 to the vertices D1, D2, D3, D4 of the dorsal cones are set. Consider the cylindrical gears ER1, ER2, ER3, ER4 with pitch circle radii. An involute tooth profile or an arbitrary tooth profile formed on the pitch circle is assumed, and this is assumed to be an equivalent cylindrical gear of the first to fourth gears A1 to A4. Here, if the equivalent number of teeth of the equivalent cylindrical gear is Z1, Z2, Z3, Z4,
Z1 = n1 / Sinθ ₁ (ii)
Z2 = n2 / Sinθ ₂ (iii)
Z3 = n3 / Sinθ ₃ (iv)
Z4 = n4 / Sinθ ₄ (v)
It can be expressed as.

Therefore, the tooth profile of this type of oscillating gear device is the equivalent cylindrical gear having the relationship obtained by the above formulas (ii) and (iii), and the tooth profile of the contour tooth is formed on the first gear A1. It is formed by generating and transferring the tooth profile to the second gear A2. The third and fourth gears A3 and A4 are formed in the same manner. That is, the first to fourth gears A1 to A4 are formed with two pairs of constant-tooth gears, and an oscillating gear device having a higher degree of freedom in machining accuracy than a conventional spherical involute tooth profile is obtained. Will be. (In the case of a one-stage reduction between the first and second gears, the third gear does not necessarily require the creation of convex teeth.)
The characteristic portions according to the present invention of the oscillating gear device having the basic configuration and the basic principle as described above will be described in detail with reference to FIGS.

  Next, each tooth profile shape of the one-stage reduction mechanism configured as described above will be described. Of the first to fourth gears, the first gear A1 and the fourth gear A4 are provided with a cylindrical roller 4a and a concave groove 4b for positioning and holding the roller, and the tooth thickness, tooth depth, etc. are equal in the direction of the tooth trace. It is configured as convex teeth 4 as high teeth. On the other hand, the second gear A2 and the third gear A3 meshing with the first and fourth gears are configured as concave teeth 5 having a predetermined arc shape meshing with the convex teeth 4 as the contour teeth.

  Of these, the second gear A2 has a difference in the number of teeth from the first gear A1, and has a predetermined amount of eccentricity due to the inclined portion 1a. Since meshing is performed while the generatrix line crosses from the meshing position to the meshing disengagement position, interference is generated at the opening of the concave tooth 5 when a simple straight concave tooth is used. Accordingly, the tooth profile of the second gear A2 is formed as a generating tooth or an approximate generating tooth obtained by generating and transferring the convex tooth 4 so that the mesh with the convex tooth 4 is properly performed as will be described in detail later. .

Further, the third gear A3 formed on the other shaft end surface of the rotating body 3 and meshed with the fourth gear A4 has the same axis as the fourth gear and the same number of teeth. Along with the movement, although the behavior along the cycloid curve is performed, the generatrix in the tooth trace direction does not intersect like the second gear, so that it is formed as an arc tooth profile having the same cross section in the tooth trace direction.
In addition, when a difference in the number of teeth is given between the third and fourth gears, and the two-stage reduction is performed, the tooth profile of the third gear is the same as the second gear, which is a generating tooth profile obtained by creating and transferring convex teeth or an approximation. It is necessary to form as a tooth. Further, the reference pitch circle diameter (PCD) of the first to fourth gears is set at the center of the tooth trace direction.

  Furthermore, the convex teeth 4 and the concave teeth 5 constituting the first to fourth gears are formed of high carbon chromium bearing steel (SUJ2) as an example, and are adjusted to a predetermined hardness by heat treatment. Specifically, the rollers 4a and the concave teeth 5 as the meshing elements have a Rockwell hardness in the range of 58 to 68 so that the hardness of the rollers 4a is higher than the hardness of the concave teeth 5 so that a predetermined load capacity can be obtained. Is set. As an example, the roller is 65 and the concave teeth are 62, and the hardness difference is set to about 3. This hardness difference may be about 2 to 5, but if the difference is too large, it is advantageous for initial familiarity, but it will affect the durability associated with the wear of concave teeth, and the hardness The opposite is true if the difference is reduced. A hardness difference of about 3 is preferable as in the above example.

  As described above, the roller 4a is configured as a reference tooth having high wear resistance and high rigidity and the concave tooth 5 is configured as a generating tooth profile having relatively low wear resistance. Even if the positioning accuracy is slightly deviated, the initial fit-in of the concave teeth 5 is promoted by the meshing of the rollers 4a and the concave teeth 5 with the swinging motion of the rotating body 3. In the above embodiment, the rollers 4a and the concave teeth 5 as convex teeth are formed of the same material, but may be different materials. In that case, the roller 4a as the reference tooth may be a material having a relatively high wear resistance with respect to the concave tooth 5.

  In addition, the conformability of the concave teeth 5 is greatly affected by the hardness, but is also greatly affected by the degree of interference associated with the positioning error. Accordingly, as described above, the length of the streaks of the concave teeth 5 is shortened, and the PCD is set near the central portion in the streak direction, thereby minimizing the interference portion with the convex teeth, so that the rollers 4a and This is more advantageous in improving the conformability of the concave teeth 5 without impairing the durability of the concave teeth 5.

  Further, the concave groove 4b constituting the convex tooth is in constant contact with the roller 4a and holds the roller 4a as a reference tooth at a predetermined position, so that the meshing compatibility between the roller 4a and the concave tooth 5 is good. Is not particularly necessary, and may be made of the same material and the same hardness as the roller 4a, or may be adjusted to a hardness comparable to the concave tooth 5 and lower than the hardness of the roller 4a. In this case, since the hardness of the concave groove 4b is lower than that of the roller 4a, the wear of the roller 4a can be relatively prevented to a minimum, and the contact surface pressure that can be placed in meshing between the roller 4a and the concave tooth 5 is stably maintained. It is more preferable because it is possible.

  That is, when the roller 4a rolls in the concave groove 4b due to long-term use and the mutual wear progresses, the wear of the concave groove 4b is worn along the outer shape of the roller 4a. Although the increase is advantageous, the wear of the roller 4a decreases the diameter of the roller 4a due to the wear and increases the surface pressure against the concave groove 4b. Therefore, it is possible to stabilize the contact surface pressure by setting the hardness of the concave groove 4b to be lower than the hardness of the roller 4a in the same manner as the concave tooth 5, and to prevent a vicious cycle of wear due to an increase in the surface pressure. Durability can be improved.

  Hereinafter, the tooth profiles of the first to fourth gears will be described in more detail. First, the first gear and the fourth gear configured as convex teeth will be described. Since the first gear A1 and the fourth gear A4 have the same tooth profile, the first gear will be described below as a representative.

  The convex teeth 4 are set so that the tooth length is longer than the tooth length of the concave teeth 5. The length is such that the interference removal width at the concave tooth opening of the second gear A2 is maximized at both ends of the tooth trace direction between the meshing start position and the meshing disengagement position associated with the swinging motion of the second gear A2. The effective meshing length is set to be long. Further, since the rollers 4a constituting the convex teeth 4 need to be locked at both ends in the tooth trace direction by retainers 7 and 8 as fixing means to the hub of the first gear A1, the length of the convex teeth 4 is as follows. The length of the roller 4a is set longer in consideration of the size of the locking portion. That is, the length of the tooth 4a of the roller 4a constituting the convex tooth 4 is a dimension obtained by adding the difference of the effective tooth length and the length of the retainer to the tooth length of the concave tooth 5. Is set as Moreover, the outer diameter of the roller 4a is the same diameter in the whole tooth line direction.

  The rollers 4a configured as the convex teeth 4 have the same number as the number of teeth of the first gear, and are positioned and held by the outer retainer 7 and the inner retainer 8 at both ends in the axial direction (tooth direction). The retainers 7 and 8 are formed in a ring shape, and annular locking claws that are engaged with the locking grooves 9 of the first and fourth gears A1 and A4 are formed at the inner ends in the axial direction. At the outer end in the axial direction, annular locking claws that hold the shaft end portion of the roller 4a are formed. The retainers 7 and 8 are made of polyamide or polyimide resin, and can be deformed by the action of a predetermined external force, and are elastically allowed to displace the rollers 4a.

The concave groove 4b that supports the roller 4a as the convex tooth 4 configured as described above is formed as an arc tooth shape corresponding to the outer shape of the roller, and the opening shape thereof is a concave tooth 5 as shown in FIG. When the roller 4a meshes with the roller 4a, the tooth pitches with the reference pitch circle diameter position as the base point so that the roller can tilt in the circumferential direction (tooth thickness direction) with the reference pitch circle diameter position (PCD) as the base point in the groove. It is formed in a so-called drum shape that continuously expands outward in the direction and inward in the tooth trace direction. (FIG. 9 shows an enlarged perspective view of the main part of FIG. 2, but the enlarged portion 4e is not shown in FIG. 2 due to the reduced scale.)
As the degree of enlargement of the enlarged portion 4e increases, the absorption margin for the misalignment of the meshing position increases, but if it is increased excessively, the positioning and holding of the roller 4a becomes unstable. Therefore, the degree of enlargement is minimized, and the elasticity of the groove 4b is reduced. It is necessary to form the tilt width to be shared by the deformation. In that sense, the enlarged shape of the enlarged portion 4e is a linear portion having the same cross section in the tooth trace direction within a predetermined range including the reference pitch circle diameter position, and continuously expands from the end portion to the end of the tooth trace direction. An enlarged portion may be formed. In this case, it is necessary to set the length of the straight portion so that the inner surface of the groove is easily elastically deformed when engaged with the concave teeth and no abnormal surface pressure is generated during the engagement. Further, the role function of the enlarged portion is to absorb an error between the gears and promote proper meshing in the same manner as the conforming action due to the hardness difference between the roller 4a and the concave tooth 5 described above. Therefore, it is possible to minimize the enlargement range of the enlargement portion 4e in consideration of the conforming action.

As shown in FIG. 5, the cross-sectional shape is formed by multiple arcs as in the cross-sectional shape of the concave tooth 5. Specifically, two arcs having a radius r larger than 1 with respect to the radius of the roller 4a are formed by offsetting the center of the arc with respect to the center of the roller 4a. Therefore, two contact points P ₀ and P ₀ are formed near the openings of the concave groove 4b and the concave teeth 5, and a predetermined contact angle smaller than 45 degrees (for example, 15 degrees) with the roller 4a. α is obtained, and predetermined oil reservoirs 4d and 5b are formed in the vicinity of the groove bottom by gradually separating from the outer periphery of the roller 4a from the contact points P ₀ and P ₀ toward the groove bottom.

The cross-sectional position in FIG. 5 shows a cross section at the center of the tooth trace direction, that is, at the reference pitch circle diameter position, and the inside and outside of the tooth trace direction from that position are larger than the arc at the reference pitch circle position corresponding to the enlarged portion 4e. A circular arc of a radius (imaginary line in FIG. 5) is formed.
Note that the contact angle α is basically an angle at the maximum meshing position where the buses overlap each other when meshing the convex teeth 4 a and the concave teeth 5.

Moreover, the contact angle α can be reduced by forming the cross section of the concave groove 4b and the concave tooth 5 as multiple arcs as described above and setting the contact points P ₀ and P ₀ near the opening, In particular, the concave tooth 5 greatly contributes to improvement of transmission efficiency and durability of each part of the gear.

That is, the load P is applied to the first gear A1 and the second contact point P ₀ in the roller 4a of the concave tooth 5 of FIG. 5 in the engaging portion of the gear A2. This load P has components for a rotational transmission force T, which is a component force in a direction parallel to the pitch cone of the first and second gears A1, A2, and an axial force F, which is also a component force in a direction perpendicular to the pitch cone. Can be considered separately. Conversely, if this axial force increases, the rotation transmission force decreases. In addition, the axial force acts as a bending force on the rotating body 3 on which the second gear A2 is formed, adversely affects the bearing that interferes with the rotating body 3, and impairs the durability of the gear device.

  Therefore, if the contact angle α is reduced, the axial force is reduced, and both transmission efficiency and durability can be improved. Note that, in the concave groove 4b constituting the convex teeth, this axial force is received by the housing 6 to which the first gear is fixed, and thus the above-described durability is not affected.

  Next, the tooth profile of the concave tooth 5 formed on the second gear A2 will be described in detail. The concave teeth 5 are formed by generating and transferring the convex teeth 4 as the first gear A1, as schematically described above.

  FIG. 6 shows that when meshing the first gear and the second gear, the concave gear teeth of the second gear are the same depth as the convex teeth of the first gear. When the second gear swings and moves in the direction of the arrow, the relationship between the roller 4a as a convex contour tooth and the concave tooth 5 as a contour concave tooth is two-dimensional. FIG. In this case, the number of teeth of the second gear is set to be larger than the number of teeth of the first gear, and the reference pitch circle diameter is set larger than the difference in the number of teeth and set in the center of the tooth line direction. The center of the first gear is centered on the axis G of the input / output shaft, the second gear has the center on the axis H of the inclined portion, and the center H rotates eccentrically around the center G.

  Therefore, when the second gear swings in the direction of the arrow, that is, moves eccentrically, the concave teeth and the rollers are engaged in a predetermined angle range E. In this case, the rollers and the concave teeth are formed to have the same width (the same diameter) in the direction of the teeth with respect to the buses M1 and M2, and therefore the proper meshing occurs at the maximum meshing position W1 where the buses overlap. At the meshing angle positions before and after that, the bus lines intersect with each other, and the concave teeth 5 interfere with the rollers 4a.

  The intersection of the buses is maximum at the meshing start position W2 and the meshing disengagement position W3, and the crossing direction has a reverse inclination before and after the maximum meshing position as a base point, so that the interference part (hatched part in the figure) is In the angle range from the meshing start position W2 to the maximum meshing position W1, it occurs on the counter-rotation direction side of the concave teeth 5 outside the reference pitch circle diameter (PCD), and occurs on the rotation direction side inside the reference pitch circle diameter. Further, in the angle range from the maximum meshing position W1 to the meshing disengagement position W3, interference portions are generated in the direction opposite to the above on the outside and inside of the reference pitch circle diameter.

  Therefore, in the opening portion of the concave tooth 5, a drum-shaped interference portion is created that expands in and out of the tooth trace direction with the reference pitch circle diameter as a base point in the meshing range from the meshing start position to the meshing disengagement position.

  The interference portion is affected by the difference in the reference pitch circle diameter between the first gear and the second gear, that is, the inclination angle of the inclined portion. If the inclination angle is small, the amount of eccentricity between the first gear and the second gear is small. When the crossing angle of the above-mentioned bus line becomes small, the above-mentioned interference part becomes small, and conversely, when the inclination angle becomes large, the crossing angle becomes large and the interference part becomes large (both the tooth trace direction, the root direction and the tooth thickness direction )Become.

  In addition, the interference portion is greatly influenced not only by the difference between the reference pitch circle diameters of the first gear and the second gear but also by the setting positions of the tooth length of the concave teeth and the reference pitch circle diameter. As the tooth trace length increases, the interference width at the end of the tooth trace direction increases. In addition, even if the tooth trace length is constant, when the reference pitch circle diameter setting position is set at, for example, the inner end and the outer end in the tooth trace direction, the distance from the reference pitch circle diameter to one end is increased. Therefore, an extremely large interference portion is generated that spreads in a so-called trumpet shape toward the other end in the tooth trace direction starting from the reference pitch circle diameter.

  Therefore, the concave teeth can be properly meshed in the predetermined meshing range by removing the interference part by a generating machine, which will be described later, but the tooth profile after the interference part removal is free of transmission efficiency and machining accuracy. Therefore, it is necessary to consider the setting of the streak length of the concave tooth that governs the interference width and the reference pitch circle diameter so that the interference width is minimized. That is, when the interference width increases, the meshing angle range with the roller 4a, particularly the contact angle with the roller at the meshing start position and the meshing disengagement position, and the component force in the axial direction increases accordingly, leading to a decrease in transmission efficiency. .

  In addition, the increase in the interference width also affects the degree of freedom of the processing form and the degree of freedom of the processing accuracy. In other words, it is possible to ensure accuracy if machining is performed using a creation machine, but it is necessary to prepare a new special machine, which is too complicated to process with a conventional linear machine. Processing steps are required, making it difficult to achieve both accuracy and productivity.

  Therefore, in this embodiment, in addition to minimizing the inclination angle by setting the speed reducing action of only one speed reduction in the first gear and the second gear, the tooth length of the concave teeth is significantly shorter than that of the convex teeth. Since it is set and the reference pitch circle diameter is set at the center of the tooth trace, the interference portion can be minimized, and both ensuring of accuracy and ensuring of freedom of productivity can be achieved.

  FIG. 7 shows the tooth profile of the concave tooth with the interference portion clarified in FIG. 6 removed, and shows the removal state of the interference portion at the front and rear meshing positions including the maximum meshing position in the meshing range. .

  In the drawing, a triangular area drawn from the root of the tooth to the opening end shows an interference removing portion from which the interference portion generated at each angular position is removed. That is, the first area E1 is an area corresponding to the interference removing portion at the meshing start position, and is located on the rotation direction side and the half rotation direction side across the reference pitch circle diameter PCD1. The second area E2 indicates an area corresponding to the interference removal unit at an intermediate angle position between the meshing start position W2 and the maximum meshing position W1. The third and fourth areas E3 and E4 indicate the same interference removal area as described above in the meshing disengagement direction from the maximum meshing position W3. Area E3 is a non-interference removing portion where interference does not occur, and indicates an area where the roller contacts at the maximum meshing position W1.

  As is clear from this figure, each of the interference canceling parts expands radially inward and outward (inside and outside of the streak direction) with the reference pitch circle diameter as a base point, but in addition to the small inclination angle, the reference pitch circle The enlargement ratio is kept relatively small by the fact that the diameter is in the center and the tooth trace length is short. Note that the area indicating the above-described interference removal unit shown in FIG. 7 is a continuous curved surface under continuous rotation, and there is no line that defines the area, but for the convenience of explanation, the removal area for each angular position is described above. Indicated.

  As is clear from the above explanation, the enlargement ratio of the interference removal portion at both ends of the tooth trace direction is reduced by minimizing the inclination angle, shortening the tooth trace length, and setting the reference pitch circle diameter at the center of the tooth trace. The contact angle with the roller at the meshing start position and the meshing disengagement position is reduced, and transmission efficiency is improved accordingly. In that sense, it is desirable that the reference pitch circle diameter is set within 30% of the length of the tooth streak inward or outward from the center of the tooth streak direction, and further deviates from the center. Since the enlargement ratio of the interference removal portion at one end is too large, it is not preferable. More preferably, it is necessary to set the reference pitch circle diameter so that the interference removal portions at both ends are substantially equal.

In that sense, the position of the reference pitch circle diameter needs to be arranged slightly outward from the center of the tooth trace. In other words, when the reference pitch circle diameter is set at the center of the tooth trace direction, there is a difference in the module between the inner end and the outer end in the radial direction, and this causes a difference in interference width between the inner end and the outer end. The outer end tends to be larger than the inner end. Fig. 7 shows the inner and outer edges of the opening when the reference pitch circle diameter is set at the center of the concave teeth (PCD1) and radially outward from the center (reference pitch circle diameter PCD2). FIG. 6 shows the relationship between the opening widths of the ends. As is apparent from this figure, in the case of PCD1, the width H ₁ of the radially outer end is wider than the width H _{2 of the} inner end, and in the case of PCD2, the opening thereof The width is reduced at the outer end side and enlarged at the inner end side to become H ₁ ′, H ₂ ′. As a result, both have substantially the same opening width. Therefore, the interference width can be made equal by setting the reference pitch circle diameter outward from the center. FIG. 8 is a cross-sectional view at the reference pitch circle diameter (PCD) position. The dotted line indicates the outer end portion in the tooth trace direction, and the one-dot difference line indicates the inner end in the tooth trace direction.

  As a method of forming the tooth profile of the concave tooth 5 of the second gear A2 and the concave groove 5 of the first and fourth gears configured as described above, there is a processing means disclosed in detail in Japanese Patent Laid-Open No. 10-235519. is there. This processing means is configured to drive the holding means for holding the workpiece via a so-called oscillating gear mechanism that is the subject of the present invention. The processing means is paired with the workpiece while oscillating the workpiece and the holding means. By moving the cutter wheel having a convex arcuate cross section in the tooth trace direction, the above-described tooth-shaped tooth profile is formed.

  That is, the concave tooth 5 of the second gear A2 is created and transferred as an appropriate tooth shape by removing the interference removing portion that interferes with the convex tooth 4, and the concave groove 4b holding the roller 4a is formed in the circumferential direction of the roller 4a. Thus, the enlarged portion 4e that expands in the tooth trace direction is formed. In this case, the formation of the concave teeth 5 of the second gear A2 is for proper engagement with the convex teeth 4 without interference with the rollers 4a, and the concave grooves 4b for positioning and holding the rollers 4a. The molding is for absorbing the variation in positioning accuracy when meshing with the concave teeth 5, and the purpose of both is different.

  Therefore, when forming the concave teeth 5, it is necessary to make the reduction ratio of the oscillating gear mechanism as the processing means and the inclination angle of the inclined portion have the same specifications as the reduction ratio and the inclination angle of the oscillating gear device. On the other hand, in forming the concave groove, it is possible to make the processing specification different from that of the concave tooth 5, but it is advantageous to increase the productivity by making the same specification. The formation of the concave groove 4b is not limited to the creation processing means using the swinging gear mechanism, and may be, for example, the forming means using the indexing means, but by the creation processing means using the swinging gear mechanism. Molding is more preferable because the pitch error between the tooth profiles can be minimized.

  That is, the concave grooves constituting the convex teeth can generally be formed by using the indexing means, but when using the indexing means, the accuracy between the pitches is governed by the accuracy of the indexing means. However, according to the generating means using the oscillating gear mechanism, the tooth profile is continuously oscillated while the workpiece is oscillated by the oscillating gear mechanism corresponding to the predetermined specifications, for example, the number of teeth and the inclination angle of the concave teeth. Can be formed, so the pitch accuracy is greatly improved.

  Next, the tooth profile of the third gear will be described. The third gear has the same number of teeth and reference pitch circle diameter as the fourth gear, and is arranged so that the apex of the pitch cone of both gears coincides with the origin O (the zero eccentricity zero position). The meshing between the gear and the fourth gear is merely repeated meshing and disengaging at the same position, there is no movement of the relative meshing position, and no deceleration action occurs between them. Therefore, in the meshing process of the third gear and the fourth gear, the crossing of the generatrix line does not occur unlike the meshing process of the first gear and the second gear. No interference occurs. Therefore, the tooth shape of the third gear, that is, the shape of the concave tooth is formed in an arc shape having the same cross section in the tooth trace direction so as to mesh with the linear roller of the fourth gear.

  Specifically, it is composed of multiple arcs so that the contact angle with the roller is 15 degrees, similar to the contact angle of the second gear. Accordingly, the third gear repeatedly engages and disengages with the fourth gear along the cycloid curve as the rotating body swings. In the substantial meshing process, the center of the concave teeth and the convex teeth are repeated. The center of the shaft moves linearly on the same line in the axial direction, and proper meshing is performed without interference.

  On the other hand, the third gear is formed on the shaft end surface of the rotating body like the second gear, and constitutes the same part as the rotating body. The second gear and the third gear can be processed by the same processing means, and the productivity as a rotating body is improved. Further, by forming the third gear into a drum shape, all of the concave grooves and the concave teeth of the first to fourth gears can be processed by the same processing means, and in particular, the processing means using the above-described swinging gear mechanism. In addition to improving the productivity, it is possible to minimize the pitch error of all meshing gears, and the meshing accuracy is greatly improved.

  Further, by making the tooth profile of the third gear the same as the tooth profile of the second gear, not only the productivity is improved, but also the openings at both ends of the concave teeth of the third gear are formed wide. Therefore, even when a positioning error with the fourth gear occurs, meshing can be promoted by a so-called self-centering action that guides the tip of the convex tooth into the concave tooth. Moreover, since the rigidity of the concave teeth is moderately weakened by forming the drum shape in this way, even if there is some error in the angular position with the fourth gear, abnormal surface pressure is generated due to the elastic deformation of the concave teeth. Can be suppressed.

  As is clear from the above description, by configuring the tooth profiles of the first to fourth gears as in the above embodiment, it is possible to achieve both ensuring of the durability of the meshing teeth and securing of the meshing accuracy, and the processing accuracy. An oscillating gear device having a high degree of freedom and positioning accuracy can be obtained.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

Sectional drawing of the rocking gear apparatus concerning this invention. The front view of the principal part of the rocking gear apparatus concerning this invention. Explanatory drawing to the equivalent spur gear of the rocking gear apparatus concerning this invention. The enlarged view of the principal part of FIG. The tooth profile section of the 1st embodiment of the rocking gear device concerning the present invention. The schematic diagram which shows the relationship between the convex-tooth and concave-tooth of the rocking gear apparatus concerning this invention. The expansion perspective view of the concave tooth of the rocking gear device concerning the present invention. Sectional drawing of FIG. The expansion perspective view which shows the tooth profile shape of a 1st gearwheel (4th gearwheel). Sectional view of a conventional oscillating gear device Explanatory drawing of the meshing part of the conventional rocking | fluctuation type gear apparatus.

Explanation of symbols

1 Input shaft 1a Inclined part 2 Output shaft 3 Rotating body 3
4 Convex Teeth 4a Roller 4b Concave Groove 4e Enlarged Part 5 Concave Teeth

Claims (4)

A first gear having n1 teeth fixed to the housing and a fourth gear having n4 teeth attached to the output shaft are arranged with their axis centers aligned with the input shaft, and a second gear having n2 teeth A rotating body integrally provided with a gear and a third gear having n3 teeth is pivotally supported by the inclined portion of the input shaft so that the second gear meshes with the first gear and the third gear meshes with the fourth gear; An XY coordinate having an origin at a point where the center point of the common spherical surface passing through each pitch circle of the first and second gears coincides with the center point of the common spherical surface passing through each pitch circle of the third and fourth gears. The axis of the input shaft is disposed on the X axis, and the meshing points of the first and second gears and the meshing points of the fourth and third gears are placed in the same quadrant or different quadrants of the XY coordinates. An oscillating gear device comprising:
The first to fourth gears are configured as bevel gears,
Of the first to fourth gears, the first gear and the fourth gear have a semicircular groove having a semicircular cross section extending radially from the gear center at equal intervals on the pitch cone, and can freely roll into the groove. The second and third gears, which are configured as convex teeth as contour teeth with the arranged cylindrical rollers and mesh with the first gear and the fourth gear, respectively, have a predetermined arc shape that meshes with the convex teeth. Configured as concave teeth,
The convex teeth are set such that the tooth length is longer than the tooth length of the concave teeth,
The concave groove that constitutes the convex teeth has an enlarged portion whose opening expands toward the end of the tooth-pitch direction with the reference pitch circle diameter as a base point so that the rollers allow tilting in the circumferential direction within the concave groove. An oscillating gear device characterized in that is formed.   The reference pitch circle diameter of the convex tooth and the concave tooth is set at the center of the tooth trace direction, and the enlarged portion of the concave groove constituting the convex tooth is a tooth with the opening portion sandwiching the reference pitch circle diameter. 2. The oscillating gear device according to claim 1, wherein the oscillating gear device is formed in a drum shape that expands outward in the stripe direction and inward in the tooth stripe direction.   2. The oscillating gear device according to claim 1, wherein the concave groove of the convex tooth is a generating tooth profile or an approximate generating tooth profile obtained by generating and transferring a convex tooth in the same manner as the concave tooth.   The oscillating gear device according to any one of claims 1 to 3, wherein a hardness of the rollers constituting the convex teeth is set to be higher than a hardness of the concave teeth.

Images