JP2008303906A - Oscillating gear device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oscillating gear device capable of providing a predetermined reduction ratio with high productivity and reduced vibration and noise. <P>SOLUTION: In this oscillating gear device formed of four bevel gears, each of first and fourth gears among the first to fourth gears meshed with and opposed to each other is formed of projecting teeth with equal height by using recessed grooves of semi-circle in cross section extending radially from the center of the gear at equal intervals on the pitch cone and cylindrical rollers rollingly disposed in the recessed grooves. Each of the second and third gears meshed with the first and fourth gears, respectively, is formed of recessed grooves corresponding to the projecting teeth. The length of the tooth trace of the recessed teeth is set shorter than the length of the tooth trace of the projecting teeth. The number of the teeth of the second gear is set larger than the number of the teeth of the first gear. The number of the teeth of the third gear and the number of the teeth of the fourth gear are set to the same number. <P>COPYRIGHT: (C)2009,JPO&INPIT

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. 9 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. A roller 4a is interposed in the meshing portion of each gear, and meshing friction is absorbed by the rolling of the roller.

As shown in FIG. 10, the roller 4a is supported by a concave groove 4b formed in the first gear A1 (fourth gear A4) so as to roll freely. 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 a concave groove and a roller, that is, a roller is interposed in the meshing portion, and a constant pressure is applied to the meshing portion to reduce backlash to zero. In principle, the frictional resistance of the meshing portion is reduced, and the transmission efficiency and positioning accuracy can be increased.

  By the way, this type of oscillating gear device is composed of four bevel gears, and is opposed to the second gear and the third gear formed at both ends in the axial direction of the rotating body in the axial direction. Since the gear and the fourth gear mesh with each other, the first gear and the second gear, and the third gear and the fourth gear, i.e., the two sets of meshing gears have a difference in the number of teeth. A two-stage reduction between the gear and the second gear and a two-stage reduction between the third gear and the fourth gear are obtained, and a wide reduction ratio from a reduced speed to a high speed is obtained.

  However, in the case of a relatively low reduction ratio, in order to obtain a two-stage reduction action as described above, in principle, it is necessary to set a large inclination angle of the inclined portion, and accordingly, the rotation of the rotating body The amplitude of dynamic motion increases and vibration noise increases. In the case of two-stage reduction, the number of teeth of the first to fourth gears needs to be different, so it is necessary to prepare unique processing equipment such as an index for the processing device, which is disadvantageous in productivity. It becomes. Further, in the case of two-stage reduction, meshing is performed with the shaft centers of the second gear and the third gear being eccentric with respect to the shaft cores of the first and fourth gears. Therefore, it is necessary to generate and transfer using a generating machine or the like, and the difference in the number of teeth is further disadvantageous in productivity.

  The present invention has been made in view of the above point, and an object of the present invention is to provide an oscillating gear device that is highly productive and advantageous in reducing vibration noise when obtaining a predetermined reduction ratio.

The means according to claim 1 of the present invention for solving the above problem comprises four conical bevel gears, a first gear having n1 teeth fixed to the housing, and n4 teeth mounted on the output shaft. The fourth gear is arranged so that the respective axis centers of the input shaft coincide with each other, and the second gear having the number of teeth n2 and the third gear having the number of teeth n3 are integrally provided. A rocking gear configured to be supported by the inclined portion of the input shaft so as to mesh with the gear and the third gear to mesh with the fourth gear, and to rotate the rotating body on the inclined portion by the rotation of the input shaft. A dynamic gear device,
The first gear and the fourth gear of the first to fourth gears meshing with each other and facing each other have a semicircular groove having a semicircular cross section extending radially from the gear center at equal intervals on the pitch cone, and the groove The second and third gears, which are configured as convex teeth as contour teeth with a cylindrical roller that is disposed so as to freely roll inside, are meshed with the first gear and the fourth gear, respectively. It is configured as a concave tooth corresponding to
The tooth length of the concave teeth is set shorter than the tooth length of the convex teeth,
The number of teeth of the second gear is set to be larger than the number of teeth of the first gear, and the number of teeth of the third gear and the fourth gear is set to the same number.

  Of the four gears, the third gear and the fourth gear have the same number of teeth, a difference in the number of teeth is given between the first gear and the second gear, and a one-stage reduction between the first gear and the second gear. By configuring so as to obtain a predetermined reduction ratio by the action, the predetermined reduction ratio can be realized by setting the inclination ratio to a small inclination angle (inclination angle of the inclined portion). The amplitude of motion can be reduced, and vibration noise can be greatly reduced.

  Further, by reducing the inclination angle, it is extremely advantageous in forming the tooth profile of the concave tooth of the second gear meshing with the convex tooth as the tooth profile of the first gear. In other words, in the oscillating gear device, the speed reduction action is performed by setting the number of teeth of the second gear to be larger than the number of teeth of the first gear and the shaft core is decentered by a predetermined value. Between the maximum meshing position and the maximum meshing position and between meshing and disengagement, the generatrix line between the gears intersects, and when the concave tooth of the second gear is a simple arc tooth profile, Since interference with the convex teeth of the gear occurs, it is necessary to provide an interference removing portion in the direction of the streaks of the concave teeth.

  This interference portion becomes larger when the inclination angle is larger, and the shape thereof becomes complicated. A special creation machine is required, which not only deteriorates productivity but also affects the degree of freedom of meshing accuracy. Therefore, by setting the first-stage speed reduction using only the first gear and the second gear, it is possible to reduce the inclination angle and the meshing interference portion (tooth direction, root direction, tooth width direction), and the second gear. Thus, the tooth profile can be simplified to improve the productivity and improve the meshing accuracy.

  In order to obtain a one-stage reduction, it is only necessary to give a difference in the number of teeth to one of the two pairs of meshing gears and make the other the same number. Although it may be on the side of the four gears, the operation on the first and second gears side is advantageous in maintaining the lubricity of each part of the gears, and the durability can be improved for long-term use. In other words, when deceleration is performed between the third and fourth gears, the second gear only repeats meshing at the same location of the first gear, and the rotating body does not rotate and is locked to the first gear. As a result, the lubricant inside the rotating body is biased to a specific position, and the flow to the meshing portion of each gear is impaired. Therefore, by giving a speed reducing action to the first and second gears, the rotating body rotates corresponding to the speed reduction ratio, so that the internal lubricant can be prevented from stagnation.

  According to a second aspect of the present invention, in the first aspect, the number of teeth of the third gear among the first to fourth gears is set to the same number of teeth as that of the first gear or the second gear. And By making the number of teeth of at least three gears the same, it is possible to share processing means such as an index table of a processing machine, and productivity is greatly improved. In particular, since the second gear and the third gear are formed at both ends of the rotating body and constitute the same part as the rotating body, the productivity is further improved by sharing the number of teeth.

  According to a third aspect of the present invention, in the first aspect, the number of teeth of the third gear is set to the same number of teeth as that of the second gear, and the bottom positions of the concave teeth of the second gear and the third gear are set. Are set to the same phase. Thus, by setting the positions of the concave teeth of the second gear and the third gear in the circumferential direction to the same phase, the maximum meshing position of the first gear and the second gear and the maximum meshing position of the third gear and the fourth gear. Are in the same phase, and generation of vibration noise due to phase shift can be prevented.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the concave tooth of the second gear has an opening portion that is outside the reference pitch circle diameter and a direction in which the tooth is inserted. It is characterized by being formed in a drum shape that expands inward. With this configuration, the crossing angle of the generatrix line between the first gear and the second gear as the reduction gear is minimized, and the interference portion with the convex teeth can be minimized. As a result, the degree of freedom in processing the concave teeth is increased, and the productivity can be improved and the degree of freedom in meshing accuracy can be increased.

  According to a fifth aspect of the present invention, in the fourth aspect, the concave tooth of the third gear is configured as an arc tooth profile having the same cross section in the tooth line direction corresponding to the cylindrical roller constituting the convex tooth. Features. By configuring in this way, in addition to optimizing the tooth profile of the second gear, the tooth profile of the third gear can be optimized, and the meshing accuracy can be increased and the transmission efficiency can be increased.

  According to a sixth aspect of the present invention, in the fourth aspect, the concave teeth of the third gear are 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. It is characterized by being. By comprising in this way, the 2nd gear and 3rd gear which comprise a concave tooth can be processed using the substantially the same processing means, and the 2nd and 3rd gears are the same components as a rotating body. As a result, productivity is greatly improved. In particular, the meshing accuracy of the fourth gear with the roller is improved by forming the tooth shape of the third gear in a drum shape.

  In other words, since the third gear and the fourth gear have the same number of teeth, the meshing at the same position is repeated without crossing the generatrix in the direction of the tooth trace as in the first and second gears. Therefore, even if it is an arc tooth type with the same cross section in the tooth trace direction, the concave tooth opening does not interfere with the roller, but the misalignment of the positioning accuracy during assembly causes the mutual bus bars in the tooth trace direction to Intersect and may cause interference with rollers. Therefore, the engagement can be promoted by the engagement inducing action by forming the concave teeth of the third gear in a drum shape. Further, the meshing rigidity of the concave teeth can be moderately reduced, and the occurrence of abnormal surface pressure during meshing can be prevented.

  As the tooth profile of the third gear, the interference removal width may be reduced similarly to the tooth profile of the second gear in the sense of preventing abnormal surface pressure, but by making it the same shape as the second gear. Since the same processing as the second gear can be performed, it contributes to the improvement of productivity. In this case, since the second gear and the third gear have the same number of teeth and the same shape, erroneous assembly during assembly can be prevented.

  The present invention can provide an oscillating gear device that is highly productive and advantageous in reducing vibration noise when obtaining a predetermined reduction ratio.

  Hereinafter, embodiments of the present invention will be described 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. Prior to the description of the embodiment according to the present invention, the basic structure and basic principle of the conventional oscillating gear device shown in FIGS. 9 and 10 will be additionally described.

  9 and 10 includes a first gear A1 having n1 teeth fixed to the housing 6 and a fourth gear A4 having n4 teeth attached to the output shaft 2 as input shafts. 1 and the rotating body 3 in which the second gear A2 having the number of teeth n2 and the third gear A3 having the number of teeth n3 are integrally provided, and the second gear A2 is connected to the first gear A1. The center point of a common spherical surface that is supported by the inclined portion 1a of the input shaft 1 so that the third gear A3 meshes with the fourth gear A4 and passes through the pitch circles of the first and second gears, and the first gear A4. 3. The axis G of the input shaft is arranged on the X axis of the XY coordinates with the origin O as the point where the center points of the common spherical surfaces passing through the pitch circles of the fourth and fourth gears coincide with each other. The axis H of the inclined portion 1a is disposed on an axis inclined at an angle of the first and second gears and the fourth and third teeth. It is configured by placing the meshing point of the vehicle 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. Similarly, the same deceleration action is performed between the third gear and the fourth gear, and two-stage deceleration 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.

  A method for obtaining the tooth profile of the oscillating gear device having the above basic configuration and basic principle 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 oscillating gear device shown in FIG. 1, and FIG. 4 is an enlarged view of a main part thereof (development views shown in FIGS. 3 and 4). Is a development based on the premise of one-stage deceleration according to the present invention, and will be described using this figure for convenience of explanation). 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 D1O1, 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 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 that of a conventional spherical involute tooth profile is obtained. Will be.

  The characteristic portions of the oscillating gear device having the above basic configuration and basic principle will be described in detail with reference to FIGS.

  First, setting of the reduction ratio will be described. 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, by setting the number of teeth n1 to n4 of the first to fourth gears to be n1 = 99, n2 = 100, n3 = 100, and n4 = 100, the reduction ratio R is R = 1 according to the equation (i). / 100, and a reduction ratio similar to that of the above-described reduction speed example is obtained.

  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, and the number of teeth of the first gear may be the same. By making the number of teeth of the gear A2 and the third gear A3 the same, the circumferential phases of the second gear and the third gear can be matched, so that the meshing positions of the first gear A1 and the second gear A2 The phases of the meshing positions of the third gear A3 and the fourth gear A4 can be matched, and the axial load acting on the rotating body acts at the same timing, so that 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, 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 include a cylindrical roller 4a and a concave groove 4b that positions and holds the roller so that it cannot be tilted. It is configured as convex teeth 4 as contour teeth with equal bamboo. 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. The reference pitch circle diameter (PCD) of the first to fourth gears is set at the center of the tooth trace direction.

  Hereinafter, the tooth profiles of the first to fourth gears will be described in more detail. 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 line 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 dimension 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 Further, the outer diameter of the roller 4a is the same in the entire region of the tooth trace 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 a 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 grooves 4b that support the rollers 4a as the convex teeth 4 configured as described above are so-called contour concaves that are uniform in cross-section in the entire tooth line direction on the pitch conical surface, that is, of the same width and depth. It is formed as a tooth, and is configured to closely support the roller 4a so as to be slidable in the direction of the teeth and not tiltable in the direction of rotation.

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. 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.

Therefore, the cylindrical roller 4a is reliably supported at the two contact points P ₀ and P ₀ of the concave groove 4b in the entire region of the tooth trace direction, the support rigidity of the roller 4a is increased, and the concave groove of the roller 4a is increased. The tilting in the rotational direction in 4b is reliably prevented, and as a result, the roller 4a and the concave groove 4b are firmly coupled to form a substantially integral convex tooth 4. Further, the support by the contact points P ₀ and P ₀ in the concave groove 4b is important for increasing the degree of freedom of processing accuracy. In other words, if the contact with the roller 4a hits the entire surface, depending on the accuracy, the contact with the roller 4a may hit the part, and the positioning of the roller 4a may be inaccurate. The degree of freedom in positioning accuracy is high, and the support rigidity of the roller 4a can be ensured relatively stably.

Further, as described above, the cross section of the concave groove 4b and the concave tooth 5 is formed by multiple arcs, and the contact points P ₀ and P ₀ are set close to the opening, thereby reducing the contact angle α. 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 roller 4a at the contact point P ₀ of the concave tooth 5 of FIG. 5 when the meshing of the first gear A1 and the second gear A2 is generated. 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. 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. As the generative transfer (processing) method, as disclosed in detail in the previous patent application (Japanese Patent Laid-Open No. 10-235519) by the present inventor, a holding means for holding a workpiece is a so-called swinging object of the present invention. Interference removal that interferes with the convex teeth 4 by moving the cutter wheel paired with the workpiece in the direction of the tooth trace while moving the workpiece and the holding means in a swinging manner. The part is removed, and the creation transfer can be performed as an appropriate tooth profile.

  The shape of the concave tooth 5 created and transferred by such a method will be described in detail below. FIG. 6 shows that when the first gear and the second gear are engaged, the concave teeth of the second gear have the same depth and the same width as the convex teeth of the first gear. When the second gear swings 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. It is a schematic diagram shown in 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 to be larger than the difference in the number of teeth and set to 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 as the contour 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 buses intersect 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 width 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 the above-described generating machine, 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 axial force 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, as long as machining is performed using a creation machine as described above, accuracy can be ensured, but a special machining machine needs to be newly prepared. An extremely complicated machining process is required, and it becomes difficult to ensure both accuracy and freedom of 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 showing the above-described interference removal unit shown in FIG. 7 is a continuous curved surface under continuous rotation, and there is no line defining the area, but the removal area for each angular position is shown for convenience of explanation. It was.

  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 on the outer end side and enlarged on the inner end side to become H ₁ ′ and 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.

  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.

As described above, by making the tooth profile of the third gear an arc tooth profile having the same cross section in the tooth direction, the existing cutting means is used in the processing of the concave teeth in the same manner as the concave grooves of the first gear and the fourth gear. Since machining can be performed linearly with a tool having a predetermined shape for each predetermined angle, machining becomes easy. In this case, if the number of teeth is the same as the number of teeth of the first gear and the fourth gear, the linear arc tooth profile of the three gears can be processed using a common indexing device, and productivity can be increased. Become.
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. In this case, if the number of teeth of the third gear (the number of teeth of the fourth gear is the same) is set to be the same as the number of teeth of the second gear, the productivity is further improved.

  Thus, 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 widened. 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 apparent from the above description, the oscillating gear device of the above embodiment is configured such that the first gear having a high degree of design freedom is formed as a convex tooth having a long tooth length, and the second gear having a low degree of design freedom. The oscillating gear device can be miniaturized by configuring the tooth as a concave tooth with a short tooth length, and the convex tooth with a long tooth length can be used as a contoured tooth that is easy to process. By setting the reference pitch circle diameter in the vicinity of the center of the tooth trace direction as a creation tooth obtained by creating and transferring the above-mentioned convex tooth or an approximate creation tooth, and increasing the degree of freedom of processing accuracy, Further, the rollers constituting the convex teeth are supported in a non-tiltable manner in the rotational direction with concave grooves having a uniform cross-section in the entire region of the tooth trace direction to increase the support rigidity of the rollers, and the rollers and concave grooves constituting the convex teeth By making the convex teeth that are firmly connected and substantially integrated, It is adapted to improve the flexibility of fit accuracy. Therefore, in the oscillating gear device of the above-described embodiment, the meshing accuracy can be increased by increasing the degree of freedom of processing accuracy and the degree of freedom of positioning accuracy, and the transmission efficiency is improved without impairing productivity. It becomes possible.

  In addition, by configuring as a one-stage speed reducer using the first and second gears, in obtaining a predetermined reduction ratio, the productivity is high, the length of the concave teeth is shortened, and the reference pitch circle diameter is set. In combination, the meshing interference portion can be minimized, and the degree of freedom in productivity can be increased. Moreover, by setting the first-stage deceleration, the reduction ratio can be set more finely than the two-stage deceleration, particularly in the reduction speed region, and the degree of freedom of setting is expanded.

  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. 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 tooth 4a Roller 4b Concave groove 5 Concave tooth 6 Housing 7 Outer retainer 8 Inner retainer

Claims (6)

Four conical bevel gears, a first gear with n1 teeth fixed to the housing, and a fourth gear with n4 teeth attached to the output shaft are arranged with their axis centers aligned with the input shaft And the input shaft so that the second gear meshes with the first gear, and the third gear meshes with the fourth gear. An oscillating gear device configured such that the rotating body performs a oscillating motion on the inclined portion by the rotation of the input shaft.
The first gear and the fourth gear of the first to fourth gears meshing with each other and facing each other have a semicircular groove having a semicircular cross section extending radially from the gear center at equal intervals on the pitch cone, and the groove The second and third gears, which are configured as convex teeth as contour teeth with a cylindrical roller that is rotatably arranged inside, are meshed with the first gear and the fourth gear, respectively. It is configured as a concave tooth corresponding to
The tooth length of the concave teeth is set shorter than the tooth length of the convex teeth,
An oscillating gear device, wherein the number of teeth of the second gear is set to be larger than the number of teeth of the first gear, and the number of teeth of the third gear and the fourth gear is set to the same number.   2. The oscillating gear device according to claim 1, wherein the number of teeth of the third gear among the first to fourth gears is set to the same number of teeth as that of the first gear or the second gear. .   The number of teeth of the third gear is set to the same number of teeth as that of the second gear, and the bottom positions of the concave teeth of the second gear and the third gear are set to the same phase. 2. The rocking gear device according to 1.   2. The concave tooth of the second gear is formed in a drum shape whose opening is enlarged outward in the tooth line direction and inward in the tooth line direction with the reference pitch circle diameter interposed therebetween. The rocking | fluctuation type gear apparatus as described in any one of -3.   5. The oscillating gear according to claim 4, wherein the concave gear of the third gear is configured as an arc tooth profile having the same cross section in the tooth trace direction corresponding to the cylindrical roller constituting the convex gear. apparatus.   5. The rocking gear according to claim 4, wherein the concave teeth of the third gear are formed in a drum shape that expands outward in the tooth line direction and inward in the tooth line direction across the reference pitch circle diameter. Dynamic gear device.

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