JP2014145433A - Series of eccentric oscillation type reduction gears - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further reduce construction cost of entire series of eccentric oscillation type reduction gears.SOLUTION: The series of reduction gears is formed from a plurality of reduction gears belonging to a plurality of frame numbers which are set in accordance with a magnitude of transmission torque. Reduction gears 10a, 10b belonging to the series comprise: internal gears 12a, 12b; first and second external gears 14a, 14b and 16a, 16b; a plurality of crankshafts 18a, 18b provided at positions offset from an axial center (O3) of the internal gears just by (L1) for oscillating the first and second external gears; and crankshaft gears 30a, 30b for transmitting power from an input side to the crankshafts. In end portions of the crankshafts, outer splines 24a, 24b are formed for concatenating the crankshaft gears and between the reduction gears 10a, 10b belonging to different frame numbers W1, W2, the size/shape of the outer splines is made common.

Description

  The present invention relates to a series of eccentric oscillating speed reducers.

  Patent Document 1 discloses an eccentric oscillating type speed reducer called a “sorting type” as shown in FIGS. 4 to 6.

  The speed reducer 910 includes an internal gear 912 and first and second external gears 914 and 916 that mesh with the internal gear 912. The first and second external gears 914 and 916 The internal gear 912 is in mesh with the internal gear 912 while swinging. In order to swing the first and second external gears 914 and 916, a plurality (three in this disclosure) of crankshafts 918 (918A to 918C) are offset from the axis O1 of the internal gear 912. The first and second external gears 914 and 916 are provided in a penetrating manner.

  The three crankshafts 918 each have a first eccentric body 920 (920A to 920C) whose eccentric phases are aligned at the same axial position, and similarly, a second eccentricity whose eccentric phases are aligned at the same axial position. It has a body 922 (922A to 922C). By rotating all the crankshafts 918 synchronously, the first external gear 914 is swung by the first eccentric body 920, and the second external gear 916 is swung by the second eccentric body 922, respectively. It is configured.

  In order to rotate the three crankshafts 918 in synchronization, outer splines 924 (924A to 924C) are formed at the ends of the crankshafts 918, respectively. Crankshaft gears 930 (930A to 930C) that transmit power from the joint shaft (input shaft) 926 side to each crankshaft 918 are connected to the outer spline 924.

  Each crankshaft gear 930 meshes simultaneously with the input pinion 932 formed on the joint shaft 926. As a result, the input pinion 932 of the joint shaft 926 rotates, whereby each crankshaft 918 is configured to rotate in the same direction at the same rotational speed.

  In this type of reducer, a plurality of frame numbers (large and small) set corresponding to the magnitude of the transmission torque are prepared, and a plurality of reducers having a plurality of gear ratio variations for each of the plurality of frame numbers. The group is provided as "Eccentric oscillating speed reducer series".

JP 2010-286098 A (FIGS. 1 to 3)

  In the series of eccentric oscillating speed reducers with such a configuration, each member of different frame numbers is basically designed for each frame number, and an outer spline formed at the end of the crankshaft is also provided. The size and shape were designed for each frame number.

  However, if the outer spline formed at the end of the crankshaft is different for each frame number, as a result, the inner spline of the corresponding crankshaft gear will also be different for each frame number. Was a factor that increased.

  This invention is made | formed in view of such a situation, Comprising: It makes it the subject to further reduce the construction cost of the whole series of eccentric rocking | fluctuation type reduction gears.

  The present invention is a series of reduction gears composed of a plurality of reduction gears belonging to a plurality of frame numbers set corresponding to the magnitude of transmission torque, the reduction gear belonging to the series includes an internal gear, An external gear internally meshing with the internal gear, a plurality of crankshafts provided at positions offset from the axis of the internal gear and swinging the external gear, and power from the input side Each of the crankshaft gears that transmit to the shaft, and an outer spline for connecting the crankshaft gear is formed at the end of the crankshaft. The above problem is solved by adopting a configuration in which the size and shape of the outer spline are made common among the reduction gears to which they belong.

  In the present invention, the outer spline formed at the end of the crankshaft for connecting the crankshaft gear is deliberately placed between the speed reducers belonging to different frame numbers set in accordance with the magnitude of the transmission torque. Same size and shape.

  Therefore, in the reduction gears belonging to different frame numbers, at least the production process of the inner spline of the crankshaft gear can be shared, and as a result, the series can be constructed at a lower cost.

  According to the present invention, it is possible to further reduce the construction cost of the entire series of eccentric oscillating speed reducers.

FIG. 2 is an overall cross-sectional view showing a comparison of two speed reducers constituting a series of eccentric oscillating speed reducers according to an example of an embodiment of the present invention. Cross-sectional view of the main part showing an enlarged view of the vicinity of the crankshaft gear of the speed reducer Diagram showing how the outer spline, inner spline, and teeth are shared in the above series Cross-sectional view of a conventional eccentric oscillating speed reducer Sectional drawing which follows the arrow VV line of FIG. Sectional view along line VI-VI in FIG.

  Hereinafter, an example of an embodiment of the present invention will be described in detail based on the drawings.

  FIG. 1 is an overall cross-sectional view showing a comparison of two reduction gears constituting a series of eccentric oscillating type reduction gears according to an example of an embodiment of the present invention, and FIG. 2 is a diagram of a crankshaft gear of the reduction gear. It is principal part sectional drawing which expands and shows the vicinity.

  In this series of eccentric oscillating speed reducers, a plurality of frame numbers are set corresponding to the magnitude of the transmission torque, and a plurality of gear ratio reduction gears are prepared for each of the plurality of frame numbers. ing.

  In addition, if it supplements about "setting of a frame number", "the frame number set corresponding to the magnitude of transmission torque" in the present invention is "the same reduction ratio, the output torque of the reducer, the peak torque, Alternatively, it means “large or small classification when attention is paid to any one of various concepts of transmission torque such as rated torque”. The method of setting the frame number is roughly divided into a method for setting corresponding to the magnitude of the transmission torque and a method for setting corresponding to the size of the reduction gear. In the case of “frame number set corresponding to the magnitude of the transmission torque”, if the speed reduction ratio is the same, gearboxes with different frame numbers will have the same magnitude relationship regardless of the specific type of transmission torque of interest. This trend is consistent with the size relationship of the reduction gears (size) (there is no reversal of the size relationship). Furthermore, in the present invention, the definition as described below is made as “series of eccentric oscillating speed reducers”, and therefore, “setting of frame number” is basically made according to the size of any concept. Even so, there is virtually no difference.

  In the present invention, the “series of eccentric oscillating speed reducers” is a group of speed reducers that are lined up as the same series, and that transmits power (except for the outer spline of the crankshaft). Deceleration having an eccentric oscillating speed reduction mechanism in which the shape of each member is basically similar, and having different transmission torque (including concepts such as rated torque and allowable torque) and reduction ratios A group of machines.

  Therefore, for example, the configuration itself of the eccentric oscillating speed reduction mechanism in the speed reducer is similar, such as a solid eccentric oscillating speed reducer and a hollow eccentric oscillating speed reducer. The reduction gears that are not included are not included in the concept of reduction gears belonging to the same series in the present invention. On the other hand, even if it is “a group of reducers lined up as the same series”, only some reducers, for example, specific reducers with specific frame numbers, bearing types and oil seal types May be different, or some other members may be different. Further, when different reduction ratios are obtained in the eccentric oscillating speed reduction mechanism, the “tooth shapes” of the external gear and the internal gear are not necessarily completely similar. However, this case is included in the concept of the same series of the present invention as long as it is “a group of speed reducers lined up as the same series”. In the above definition, “having an eccentric oscillating type speed reduction mechanism in which the shape of each member is basically similar” is basically similar. It is intended to include the case where only a part of the members or only a part of the members are non-similar. In addition, for example, as in the reducer belonging to the old series and the reducer belonging to the improved new series, “reducers that have not been lined up as being the same series (different series over time)” This is not included in the concept of the speed reducer belonging to the same series according to the present invention. This is because the same or similar parts may be used between the old series and the improved new series, but the reduction gear included in the series is used to increase the transmission torque of the entire series. This is because structural modifications common to the above are added.

  1 (A) and 2 (A) show a reduction gear 10a with a frame number W1 having a small transmission torque, and FIGS. 1 (B) and 2 (B) show a reduction gear 10b with a frame number W2 larger than that. Each of them shows. In the eccentric oscillating speed reducer series, it is practically difficult to obtain various speed ratio variations in the eccentric oscillating speed reduction mechanisms G2a and G2b. The first reduction mechanism G1a, G1b (ie, adjustment of the combination of the input pinions 32a, 32b and the crankshaft gears 30a, 30b) is ensured (however, the eccentric oscillation type reduction mechanisms G2a, G2b Different reduction ratios may be prepared). Accordingly, the members of the eccentric oscillating type deceleration mechanisms G2a and G2b are basically similar to each other even if the frame numbers are different, and are functionally the same. Therefore, here, for convenience, the same reference numerals are given to the functionally identical members, and a member of the frame number W1 corresponding to the speed reducer 10a has a frame number W2 of a greater than that at the end of the code. For the members related to the speed reducer 10b, after adding b to the end of the same reference numeral, the speed reducers 10a and 10b of both frame numbers W1 and W2 will be described simultaneously.

  In this embodiment, the power of a motor (not shown) is input via joint shafts (input shaft: the whole is not shown and is equivalent to the joint shaft 926) 26a, 26b. Input pinions (input-side gears) 32a and 32b are directly cut and formed at the ends of the joint shafts 26a and 26b on the non-motor side.

  The input pinions 32a and 32b mesh with the plurality of crankshaft gears 30a and 30b at the same time to form first reduction mechanisms G1a and G1b. The reduction ratios of the reduction gears 10a and 10b are adjusted by adjusting the reduction ratios of the first reduction gear mechanisms G1a and G1b. In this embodiment, each of the crankshaft gears 30a and 30b is provided with three (only one is shown) and is connected to three (only one is shown) crankshafts 18a and 18b, respectively. The configuration in the vicinity of the crankshafts 18a and 18b and the crankshaft gears 30a and 30b will be described in detail later.

  The crankshafts 18a and 18b correspond to the input shafts of the eccentric oscillating speed reduction mechanisms G2a and G2b. In this embodiment, three crankshafts 18a and 18b (only one is shown) are provided. The crankshafts 18a and 18b are arranged at intervals of 120 degrees in the circumferential direction at positions offset by L1a and L1b from the axial centers O1a and O1b of the internal gears 12a and 12b. Each crankshaft 18a, 18b is formed with a first eccentric body 20a, 20b at the same axial position, and adjacent to the first eccentric body 20a, 20b, a second eccentric body at the same axial position. 22a and 22b are formed. The first eccentric bodies 20a, 20b and the second eccentric bodies 22a, 22b of the crankshafts 18a, 18b are aligned in eccentric phase. The eccentric phase difference between the first eccentric bodies 20a, 20b and the second eccentric bodies 22a, 22b is 180 degrees.

  First external gears 14a and 14b are incorporated on the outer circumferences of the first eccentric bodies 20a and 20b of the crankshafts 18a and 18b via first roller bearings 34a and 34b. Second external gears 16a and 16b are incorporated on the outer circumferences of the second eccentric bodies 22a and 22b of the crankshafts 18a and 18b via second roller bearings 36a and 36b. As a result, the first eccentric bodies 20a, 20b on the three crankshafts 18a, 18b rotate synchronously to swing the first external gears 14a, 14b, and similarly, the three crankshafts 18a , 18b, the second eccentric gears 16a, 16b can be swung by the second eccentric bodies 22a, 22b rotating synchronously.

  The first carriers 38a, 38b and the second carriers 40a, 40b are arranged on both sides in the axial direction of the first external gears 14a, 14b and the second external gears 16a, 16b, and the crankshafts 18a, 18b are arranged. Is supported by the first carrier 38a, 38b and the second carrier 40a, 40b via a pair of tapered roller bearings 44a, 44b and 46a, 46b. The first carrier 38a, 38b and the second carrier 40a, 40b are supported by the casing 52a, 52b via a pair of angular ball bearings 48a, 48b and 50a, 50b. Note that carrier bridges 43a and 43b protrude from the second carriers 40a and 40b, and the first carriers 38a and 38b and the second carriers 40a and 40b pass through the carrier bridges 43a and 43b, so that the knock pins 53a, 53b and a bolt (not shown) are connected and integrated.

  The first external gears 14a and 14b and the second external gears 16a and 16b are in mesh with the internal gears 12a and 12b. In this embodiment, the internal gears 12a and 12b are rotatably incorporated in the internal gear main bodies 13a and 13b integrated with the casings 52a and 52b, and the internal gear main bodies 13a and 13b. , 12b and outer pins 15a, 15b constituting the inner teeth. The number of teeth of the internal gears 12a, 12b (the number of the external pins 15a, 15b) is slightly smaller than the number of teeth of the first external gears 14a, 14b and the second external gears 16a, 16b (only 1 in this example). ) Many.

  A first arm (not shown) of the robot is connected to the casings 52a and 52b via bolts (only bolt holes 53a and 53b are shown), and the robots of the robot are connected to the second carriers 40a and 40b via bolts (not shown). Second arms (not shown) are connected to each other.

  Here, the configuration in the vicinity of the crankshaft gears 30a and 30b will be described in detail.

  Referring mainly to FIG. 2, outer splines 24a and 24b are formed at the respective ends of a plurality of (three in this embodiment) crankshafts 18a and 18b. The crankshaft gears 30a and 30b are connected to the crankshafts 18a and 18b in a cantilever state via the outer splines 24a and 24b.

  More specifically, the crankshafts 18a and 18b are provided with tip portions 19a and 19b whose end surfaces in the axial direction are slightly chamfered, and the retaining ring recesses 21a and 21b are provided at the axially inner positions of the tip portions 19a and 19b. I have. Retaining rings 54a, 54b for positioning the crankshaft gears 30a, 30b in the axial direction are fitted into the retaining ring recesses 21a, 21b.

  Further, recessed portions 58a and 58b deeper than the tooth bottoms of the outer splines 24a and 24b are formed on the inner sides in the axial direction of the outer splines 24a and 24b of the crankshafts 18a and 18b. The formation lengths of the outer splines 24a and 24b in the axial direction are L3a and L3b.

  In this embodiment, the outer splines 24a and 24b are formed by rolling (plastic working). The recesses 58a and 58b also function as a “material escape” space during processing.

  On the other hand, the crankshaft gears 30a and 30b mesh with the input pinions 32a and 32b, and transmit power from the input side to the crankshafts 18a and 18b. The crankshaft gears 30a and 30b have teeth 33a and 33b meshing with the input pinions 32a and 32b on the outer periphery, and inner splines 31a and 31b engaged with the outer splines 24a and 24b of the crankshafts 18a and 18b on the inner periphery. Is provided. The inner splines 31a, 31b are formed over the entire axial length L5a, L5b of the crankshaft gears 30a, 30b (however, the entire axial length L5a, L5b of the crankshaft gears 30a, 30b is not limited). It is not necessary to form over a portion, and a portion that is not partially formed may remain).

  Reference numerals 61a and 61b in FIGS. 1 and 2 are spacers for determining the axial positions of the crankshaft gears 30a and 30b on the crankshafts 18a and 18b, respectively.

  In this embodiment, the crankshaft gears 30a and 30b are incorporated into the outer splines 24a and 24b in a state where grease is applied to the outer splines 24a and 24b (and the recesses 58a and 58b).

  In this embodiment, the outer spline 24b of the crankshaft 18b having the larger frame number W2 and the inner spline 31b of the crankshaft gear 30b are connected by “an interference fit” (described later).

  Here, the speed reducer 10a in FIGS. 1A and 2A corresponds to the speed reducer 10a having the specifications of the frame number W1 and the speed reduction ratio R3 in the list shown in FIG. The speed reducer 10b in FIGS. 1B and 2B corresponds to the speed reducer 10b having the specifications of the frame number W2 and the speed reduction ratio R2 in the list shown in FIG. The transmission torque of the frame number W2 is larger than the transmission torque of the frame number W1, and the reduction ratio R3 is larger than the reduction ratio R2. That is, W1 <W2 and R2 <R3.

  First, attention is paid to the outer spline 24a of the crankshaft 18a of the speed reducer 10a with the frame number W1 and the outer spline 24b of the crankshaft 18b of the speed reducer 10b with the frame number W2. As described above, in this embodiment, the outer splines 24a and 24b are processed by rolling (plastic processing).

  As shown in FIG. 2A, in this embodiment, the pitch circle radius of the outer spline 24a of the crankshaft 18a of the speed reducer 10a with the frame number W1 is Rs1. The module is Ms1 and the number of teeth is Ts1. On the other hand, as shown in FIG. 2B, the pitch circle radius of the outer spline 24b of the crankshaft 18b in the speed reducer 10b with the frame number W2 is Rs1. The module is Ms1, and the number of teeth is Ts1. That is, between the different frame numbers W1, W2, the outer splines 24a, 24b of the crankshafts 18a, 18b have the same pitch circle radius, Rs1, both modules, Ms1, and the number of teeth are both Ts1. There are common sizes and shapes (including the tip portions 19a and 19b, the retaining ring recesses 21a and 21b, and the recesses 58a and 58b).

  3, in this embodiment, not only the speed reducers 10a and 10b, but also the speed reducers 10c, 10d and 10e with the frame number W1, and the speed reducer 10f with the frame number W2, 10g and 10h are all the same size and shape as the outer splines 24a and 24b. However, in the present invention, it is not required that the size and shape of the outer spline be the same in all the reduction ratios of the paired frame numbers (some may be common).

  Next, attention is paid to the inner spline 31a of the crankshaft gear 30a of the speed reducer 10a with the frame number W1 and the inner spline 31b of the crankshaft gear 30b of the speed reducer 10b with the frame number W2. In this embodiment, the inner splines 31a and 31b are processed by broaching (may be processed by a gear shaper or the like).

  In this embodiment, both the inner spline 31a of the crankshaft gear 30a with the frame number W1 and the inner spline 31b of the crankshaft gear 30b with the frame number W2 (to engage with the same outer splines 24a and 24b) are pitched. The circle radius is Rs1, the module is Ms1, and the number of teeth is Ts1. That is, between the different frame numbers W1, W2, the inner splines 31a, 31b of the crankshaft gears 30a, 30b have the same pitch circle radius Rs1, both modules Ms1, and both teeth Ts1, and are the same. The size and shape are common. In other words, both the inner spline 31a of the frame number W1 and the inner spline 31b of the frame number W2 can be engaged and connected to both the outer spline 24a of the frame number W1 and the outer spline 24b of the frame number W2. It is.

  In this embodiment, as shown by white “◯” marks in FIG. 3, the speed reducers corresponding to the black “●” speed reducers, that is, the speed reducers 10c, 10d, 10e of the frame number W1, And in the speed reducers 10f, 10g, and 10h of the frame number W2, an inner spline (31) having the same size and shape (pitch circle radius Rs1, module Ms1, number of teeth Ts1) is formed.

  Further, when focusing on the tooth portion 33a of the crankshaft gear 30a of the speed reducer 10a with the frame number W1 and the tooth portion 33b of the crankshaft gear 30b of the speed reducer 10b with the frame number W2, in this embodiment, The pitch circle radius of the tooth portion 33a of the crankshaft gear 30a is Rg1, the module is Mg1, and the number of teeth is Tg1. On the other hand, the crankshaft gear 30b of the frame number W2 also has a pitch circle radius of Rg1, a module of Mg1, and a number of teeth of Tg1. That is, between the different frame numbers W1 and W2, the pitch circle radii of the teeth 33a and 33b of the crankshaft gears 30a and 30b are both Rg1, the modules are both Mg1, and the number of teeth is both Tg1, and they are the same. The size and shape are common (see double circle “◎” in FIG. 3).

  In other words, the crankshaft gear 30a of the speed reducer 10a with the frame number W1 & reduction ratio R3 and the crankshaft gear 30b of the speed reducer 10b with the frame number W2 & reduction ratio R2 have the same internal splines 31a and 31b ("O"). In addition, the teeth 33a and 33b are also common (the module Mg1 and the number of teeth Tg1 are common: “◎” marks), and are completely identical (joint) members. That is, the crankshaft gears 30a and 30b themselves are shared between different frame numbers W1 and W2.

  The input pinion 32a meshed with the crankshaft gear 30a of the frame number W1 has a pitch circle radius of Rg2, a module (common to the module Mg1 of the crankshaft gears 30a and 30b) Mg1, and the number of teeth Tg2. Thus, the reduction ratio R3 (Tg1 / Tg2) is realized by meshing with the crankshaft gear 30a. The input pinion 32b of the frame number W2 has a pitch circle radius Rg3, a module Mg1 (common to the module Mg1 of the crankshaft gears 30a and 30b), and the number of teeth Tg3, and meshes with the crankshaft gear 30b. Thus, a reduction ratio R2 (Tg1 / Tg3) (smaller than R3) is realized.

  As is apparent from this configuration, the crankshaft gears 30a and 30b themselves are shared by the speed reducer 10a and the speed reducer 10b only having the same size and shape of the inner splines 31a and 31b of the crankshaft gears 30a and 30b. In addition, the modules of the teeth 33a and 33b of the crankshaft gears 30a and 30b are both equal to Mg1, and further, “the sum of the pitch circle radius Rg1 of the crankshaft gear 30a and the pitch circle radius Rg2 of the input pinion 32a”. And “the sum of the pitch circle radius Rg1 of the crankshaft gear 30b and the pitch circle radius Rg3 of the input pinion 32b” are both the axis O1a, O1b of the internal gears 12a, 12b and the axis of the crankshaft 18a, 18b. It is equal to the distances L1a and L1b to O3a and O3b (Rg1 + Rg2 = L1a and Rg1 + Rg3 = L1b) It is possible if you meet.

  Therefore, the common use of the crankshaft gear is, for example, in the reduction gear 10d with the frame number W1 & reduction ratio R2 and the reduction gear 10f with the frame number W2 & reduction ratio R1, as indicated by the square “□” in FIG. There is also a possibility that it can be realized. Furthermore, as indicated by black “▲” marks in FIG. 3, there is a possibility that the reduction can be realized also with the reduction gear 10e with the frame number W1 & reduction ratio R4 and the reduction gear 10g with the frame number W2 & reduction ratio R3. In this case, the modules of the tooth portion (33) of the crankshaft gear (30) of the speed reducers 10d and 10f (or speed reducers 10e and 10g) are the same as each other (or the speed reducers 10e and 10g). As long as they are the same), the module Mg1 of the tooth portion (33) of the crankshaft gear (30) of the reduction gears 10a and 10b may be different.

  When sharing the outer spline (24), the inner spline (31), or the tooth part (33), the size and shape satisfying the allowable value of the spline tooth surface pressure or tooth surface pressure with a large frame number Set to. As a result, the smaller frame number automatically satisfies the allowable value. If it is difficult to ensure the allowable value with a large frame number, for example, a) strengthening the interference fit, b) increasing the axial length and tooth width of the inner spline, c) surface It is advisable to take some measures such as increasing the tooth surface strength by treatment. These treatments may be performed for the entire series (both large frame numbers and small frame numbers), but may be performed only for large frame numbers with strict tolerances. That is, if the size and shape of the outer spline are shared between the frame numbers, the crankshaft gear itself does not necessarily have to be shared.

  For example, as described above, in the present embodiment, only in the large frame number W2, the outer spline 24b of the crankshaft 18b and the inner spline 31b of the crankshaft gear 30b are connected by an interference fit, and the small frame number The outer spline 24a and the inner spline 31a of W1 are clearance fits with better assembly. From the same viewpoint, for example, even if both are interference fits, the interference fit of the outer spline 24a and the inner spline 31a of the smaller frame number W1 is smaller than that of the outer spline 24b and the inner spline 31b of the larger frame number W2. It may be a looser interference fit. Thus, in the present invention, different treatment for each specific frame number is not prohibited.

  To make the interference fit stronger (or to make the gap fit smaller), for example, rolling (or cold forging or hobbing without changing the basic processing setup) ), It is possible to employ a method of adjusting the spline and the tooth thickness of the tooth portion to be thicker by finishing the processing slightly earlier than the original processing completion point. Thereby, differentiation of the tooth thickness of a large frame number and a small frame number is realizable, without impairing the merit of common processing setup. This type of differentiation may be handled only on the inner spline side, only on the outer spline side, or on both the inner and outer splines.

  In view of the above circumstances, in the present invention, the phrase “the size and shape of the outer spline is common among the speed reducers belonging to different frame numbers” should not be strictly grasped, but the pitch circle radius, the tooth thickness Alternatively, the concept that the formation length of the outer spline in the axial direction is slightly different should be included. In other words, “As a result, the same inner spline (of the crankshaft gear) (which is manufactured in a common manufacturing process, but by adjusting the processing time etc., the inner spline has a different degree of interference fit. If the interchangeability is ensured to be able to engage with the outer spline (of the crankshaft) of two or more frame numbers ”, the outer spline It can be said that “size and shape are common” is satisfied.

  Next, the operation of this eccentric rocking speed reducer series will be described.

  First, the operation of a single unit of the speed reducers 10a and 10b will be described.

  When a motor (not shown) rotates, this rotation is transmitted to the joint shafts 26a and 26b, and the input pinions 32a and 32b formed at the tips of the joint shafts 26a and 26b rotate. Since the input pinions 32a and 32b are meshed simultaneously with the three crankshaft gears 30a and 30b, the meshing of the input pinions 32a and 32b and the crankshaft gears 30a and 30b causes the three crankshafts 18a and 18b to be engaged. The input pinions 32a and 32b and the crankshaft gears 30a and 30b rotate at the same rotational speed in the same direction while being decelerated to a gear ratio.

  As a result, the three first eccentric bodies 20a and 20b formed at the same position in the axial direction of each crankshaft 18a and 18b rotate synchronously to swing the first external gears 14a and 14b, and the crankshaft Three second eccentric bodies 22a and 22b respectively formed at the same position in the axial direction of 18a and 18b rotate synchronously to swing the second external gears 16a and 16b.

  Since the first external gears 14a and 14b and the second external gears 16a and 16b are in mesh with the internal gears 12a and 12b, respectively, the first external gears 14a and 14b and the second external gear 16a , 16b oscillate once, the first external gears 14a, 14b and the second external gears 16a, 16b differ in the number of teeth from the internal gears 12a, 12b (in this embodiment, one tooth Min) The phase in the circumferential direction shifts (rotates). This rotation component is transmitted to the first carriers 38a and 38b and the second carriers 40a and 40b as revolutions around the axes O1a and O1b of the internal gears 12a and 12b of the crankshafts 18a and 18b. The first carriers 38a, 38b and the second carriers 40a, 40b are connected by knock pins 53a, 53b and bolts (not shown) via carrier bridges 43a, 43b. Therefore, after all, the rotation of the joint shafts (input shafts) 26a and 26b causes the first arm connected to the casings 52a and 52b and the second arm connected to the second carriers 40a and 40b to be relatively Can be rotated.

  The recesses 58a and 58b of the crankshafts 18a and 18b function as spaces for securing the escape of the material when the outer splines 24a and 24b are manufactured by rolling, and the outer splines 24a and 24b and the inner splines 31a. , 31b also functions as a grease reservoir for grease.

  Next, the operation of the series will be described.

  As already mentioned, in this type of eccentric oscillating type reduction gear series, it is practically difficult to obtain various speed ratio variations in the eccentric oscillating type reduction mechanisms G2a and G2b. Variations of the reduction ratio are obtained by a combination of the input pinions 32a and 32b of the first reduction mechanisms G1a and G1b and the crankshaft gears 30a and 30b. Therefore, conventionally, the crankshaft (18), which is the input shaft of the eccentric oscillating speed reduction mechanism, also has a difference in the diameter of the eccentric body (22) according to the difference in frame number. Naturally, it was considered that the size and shape of the outer spline (24) formed on the crankshaft (18) was different for each frame number.

  In particular, as is apparent from the depiction of FIG. 4, the outer spline 924 of the crankshaft 918 has been formed by hobbing in the past, and thus a region 925 called “rounding up” is inevitably necessary. there were. Therefore, if the size and shape of the outer spline 924 of the crankshaft 918 are to be made common, the cutting allowance of the crankshaft (918) with a smaller frame number becomes relatively large and the “round-up” is very large. Therefore, the manufacturing problem of requiring a useless axial space also arises. This is also understood as a potential reason that the idea of sharing the outer spline (924) between different frame numbers did not occur.

  Therefore, conventionally, since the outer spline (24) and the inner spline (31) are different for each frame number, it is necessary to manufacture a very wide variety of crankshaft gears (30), which has been a factor in increasing costs. .

  However, for example, the manufacturing problem due to the hobbing can be substantially avoided by forming the outer spline by rolling (plastic working) as in this embodiment. In addition, plastic working other than rolling includes cold forging and the like, but none of these manufacturing problems (such as hobbing) occur. Furthermore, plastic processing also has the advantage that the strength of the tooth surface is improved by work hardening. A favorable characteristic in terms of durability (rather than hobbing) can be obtained.

  In this embodiment, based on this idea, the outer splines 24a and 24b are formed by rolling (plastic working), and the outer splines 24a and 24b of the crankshafts 18a and 18b are made common between the different frame numbers W1 and W2. Is realized.

  As a result, at least the inner splines 31a, 31b of the crankshaft gears 30a, 30b can be shared between the different frame numbers W1, W2, and the manufacturing system of the crankshaft gear (30) of the entire series can be further simplified. Therefore, the cost can be reduced accordingly.

  However, although the present invention was created by paying attention to the processing of the outer spline by plastic working in this way, the present invention is based on the viewpoint of “commonization of the size and shape of the outer spline”. If it catches, processing methods other than plastic processing are not prohibited at all. For example, the outer spline may be shared by hobbing if an axial space for cutting the tool can be secured. Further, for example, an outer spline having a large frame number may be formed by hobbing, and an outer spline having a smaller frame number may be manufactured by plastic working such as rolling or cold forging. Even in this case, since the crankshaft gear can be shared between different frame numbers (at least by sharing the outer spline), the crankshaft gears having different inner splines are prepared for each frame number. This eliminates the need for the whole series and further simplifies the manufacturing system of the crankshaft gear, thereby reducing the cost.

  Returning to the description of the operation of this embodiment. When both the outer splines 24a and 24b are realized by the “same processing method” as in the present embodiment, the outer splines 24a and 24b are rotated by the same setup using the same tool. It becomes possible to form by fabrication (or cold forging by the same setup using the same mold), and further cost reduction can be realized.

  In the present embodiment, the module of the tooth portions 33a and 33b of the crankshaft gears 30a and 30b is made common in a part between the frame numbers W1 and W2. The manufacturing system of the tooth part (33) and the input pinion (32) of 30) can be further simplified, and the cost can be further reduced.

  In particular, since the relationship between the set reduction ratios R2 and R3, the crankshaft gears 18a and 18b, and the pitch circle radii Rg1, Rg2 and Rg3 of the input pinions 32a and 32b is well utilized, the completely same crankshaft gear 18a. (= 18b) can be shared as it is. In an actual series, there are almost many types of frame numbers and reduction ratios than the example in FIG. 3, so the number of crankshaft gears that can be fully shared depends on the design. Is also possible.

  In the above embodiment, the crankshaft gear is configured such that the power from the input side is input to the crankshaft gear via the input pinion of the parallel shaft system, but the crankshaft gear itself is an orthogonal gear (for example, Bevel gear or the like), and power from the input side may be transmitted to the crankshaft gear through an orthogonal input pinion.

  Moreover, although the speed reducer which has three crankshafts was shown in the said embodiment, if the number of the crankshafts of the speed reducer in this invention is two or more, it will not be specifically limited to three.

10a, 10b ... reduction gears 12a, 12b ... internal gears 14a, 14b, 16a, 16b ... first and second external gears 18a, 18b ... crankshafts 24a, 24b ... external splines 30a, 30b ... crankshaft gears 31a, 31b ... Inner spline 33a, 33b ... Teeth

Claims (7)

A series of reduction gears composed of a plurality of reduction gears belonging to a plurality of frame numbers set according to the magnitude of the transmission torque,
The speed reducer belonging to the series includes an internal gear, an external gear internally meshing with the internal gear, and a plurality of gears which are provided at positions offset from the axis of the internal gear and swing the external gear. And a crankshaft gear that transmits the power from the input side to the crankshaft, respectively.
An outer spline for connecting the crankshaft gear is formed at the end of the crankshaft,
A series of eccentric oscillating speed reducers characterized in that the size and shape of the outer spline are common among speed reducers belonging to different frame numbers. In claim 1,
The outer spline is formed by plastic working. A series of eccentric oscillating speed reducers. In claim 1 or 2,
A series of eccentric oscillating type speed reducers characterized in that the crankshaft gear itself is shared among speed reducers belonging to different frame numbers. In any one of Claims 1-3,
Eccentric oscillating type characterized in that the outer spline that is common to the speed reducers belonging to the different frame numbers is set to a size and shape that satisfies the allowable value of the spline tooth surface pressure in the larger frame number. Series of speed reducers. In any one of Claims 1-4,
Of the frame numbers that are common to the outer splines, in the larger frame number, the outer spline of the crankshaft and the inner spline of the crankshaft gear are connected by an interference fit. A series of eccentric oscillating speed reducers. In claim 5,
Among the frame numbers that are common to the outer splines, in the smaller frame number, the outer spline of the crankshaft and the inner spline of the crankshaft gear are connected by a clearance fit. A series of eccentric oscillating speed reducers. In any one of Claims 1-6,
A series of eccentric oscillating type speed reducers characterized in that the gear module of the crankshaft gear is the same among speed reducers belonging to different frame numbers.

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