JP4249447B2 - Power transmission device for valve drive - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power transmission device for driving a valve provided with a parallel shaft gear mechanism, an external gear having a slight difference in the number of teeth, and an internally meshing planetary gear mechanism having an internal gear.
[0002]
[Prior art]
A power transmission device including a parallel shaft gear mechanism, an external gear having a slight difference in the number of teeth, and an internal meshing planetary gear mechanism having an internal gear, is small and can obtain a large reduction ratio. Setting and changing the overall total reduction ratio is relatively easy. Therefore, it is widely used for opening and closing valves.
[0003]
FIG. 9 shows a driving device disclosed in Japanese Patent Laid-Open No. 2002-115748. This drive device P1 is a combination of this type of power transmission device G1 and a motor 10. The power transmission device G1 includes a parallel shaft gear mechanism 12 and an intermeshing planetary gear mechanism 14.
[0004]
The casing 16 of the driving device P1 is separated into three blocks B1 to B3 by two plates 18 and 20. The first block B1 is mainly the motor 10 and its control device (auxiliary machine) 24, the second block B2 is mainly the parallel shaft gear mechanism 12, and the third block B3 is mainly an intermeshing planetary gear mechanism. 14, respectively.
[0005]
A first pinion 28 of the parallel shaft gear mechanism 12 is provided on the output shaft 26 of the motor 10 (input shaft of the parallel shaft gear mechanism 12).
[0006]
The parallel shaft gear mechanism 12 includes a first stage reduction mechanism 32 composed of the first pinion 28 and the first gear 30 and a second stage reduction mechanism 38 composed of the second pinion 34 and the second gear (output gear) 36. Prepare.
[0007]
The intermeshing planetary gear mechanism 14 is incorporated into an input shaft 40 in which the second gear 36 is incorporated, an eccentric body 42 integrated with the input shaft 40, and swingable and rotatable on the outer periphery of the eccentric body 42. An external gear 46 and an internal gear 48 having a number of teeth that is one more than the number of teeth of the external gear 46 (having a slight difference in the number of teeth) are included as components. The output shaft 50 is connected to the external gear 46 via a carrier 52 that transmits only the rotation component of the external gear 46. Further, a through hole 50A for inserting a rod-shaped object (not shown) such as a spanner at the time of manual operation is formed at the tip of the output shaft 50.
[0008]
Note that so-called involute tooth profiles are employed for the tooth profiles of the internal gear 48 and the external gear 46.
[0009]
Briefly, the rotation of the output shaft 26 of the motor 10 (the input shaft of the parallel shaft gear mechanism 12) is decelerated by the two-stage parallel shaft gear mechanism 12, and the inscribed mesh planet is connected via the second gear 36. It is transmitted to the input shaft 40 of the gear mechanism 14. When the input shaft 40 rotates, the external gear 46 oscillates and rotates while inscribed in the internal gear 48 via the eccentric body 42 integral therewith. As a result, the external gear 46 is one of the input shaft 40. Each rotation rotates slowly by an amount corresponding to the difference in the number of teeth between the internal gear 48 and the external gear 46. Therefore, by taking out the rotation corresponding to the rotation component of the external gear 46 from the output shaft 50 through the carrier 52, a large reduction ratio can be obtained in one stage. This type is generally referred to as “oscillating and rotating type”. A valve stem (not shown) is connected to the output shaft 50.
[0010]
[Problems to be solved by the invention]
However, since the device disclosed in Japanese Patent Laid-Open No. 2002-115748 has not been particularly examined for the arrangement of each speed reduction mechanism, a large wasted space and the rigidity of the entire device is not necessarily high. I think that the.
[0011]
Also, since the blocks that accommodate the parallel shaft gear mechanism and the intermeshing planetary gear mechanism are sequentially arranged in a state of being separated by the plates, the length in the axial direction is inevitably easily increased, As the plate was present, the weight was likely to increase.
[0012]
The present invention has been made to solve such problems, and is a structure in which a parallel shaft gear mechanism and an intermeshing planetary gear mechanism, which have been conventionally arranged without particular examination, are rationally fused. It is an object of the present invention to improve the support rigidity of each gear mechanism and reduce the weight, and in particular to reduce the axial size of the entire device.
[0013]
[Means for Solving the Problems]
The present invention relates to a power transmission device for driving a valve in which a parallel shaft gear mechanism and an internally meshing planetary gear mechanism including an external gear and a small number of teeth are accommodated in a casing. In the casing containing the internal mesh planetary gear mechanism, at least one of the bearing portions that support the rotation of the gear of the parallel shaft gear mechanism is within an axial range in which the internal gear exists. and is arranged in a position radially external to the internal gear, said internal gear, which has a portion of its body and teeth, by Rukoto to integrating the body of the casing and the internal gear, the It solves the problem.
[0014]
In the present invention, “the casing housing the intermeshing planetary gear mechanism has a bearing portion (at least one) for supporting the rotation of the gear of the parallel shaft gear mechanism in the axial direction in which the internal gear is present. within the scope of, and to be placed in and radially outer position of the internal gear (hereinafter simply referred to as the outer periphery of the internal gear). "
[0015]
As a result, the bearing portion of the parallel shaft gear mechanism is supported by a highly rigid portion supporting the internal gear (which is the heaviest member) in the casing of the power transmission device. Support rigidity can be obtained.
[0016]
Further, since the space accommodating the parallel shaft gear mechanism and the space accommodating the intermeshing planetary gear mechanism can be merged into one block, the plate (corresponding to the conventional plate 20) This eliminates the need to arrange the weight and can further reduce the weight.
[0017]
Further, since the bearing portion is incorporated on substantially the same plane as the main portion of the intermeshing planetary gear mechanism, the axial length of the entire power transmission device can be reduced accordingly.
[0018]
In addition, the effect corresponding to the present invention can be obtained also when “only a part” of a specific bearing portion of the parallel shaft gear mechanism is present in the “outer periphery of the internal gear”. Therefore, even when “only a part” of a specific bearing portion exists in the “outer periphery of the internal gear”, it is included in the concept of “arrangement of the bearing portion on the outer periphery of the internal gear”.
[0019]
The present invention is particularly, the internal gear, and having a portion of the body and teeth, the casing and since the internal gear and the main body is configured as an integral, virtually internal gear Since the bearing portion of the parallel shaft gear mechanism is disposed in itself, it is possible to realize a compact in the radial direction and further reduce the weight.
[0020]
Further, when the tooth profile of the internal gear is composed of a semicircular groove and a roller-like pin rotatably engaged with the groove, the groove and the pin are in contact with the convex and concave portions. So it is excellent in durability. Further, when hardening the pin than casings, for the body of the internal gear for example with a weight, with weight reduction using aluminum-based metal, than casing only required tooth portion of high strength When a material having high hardness is used, it is possible to achieve both weight reduction and high durability.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0022]
FIG. 1 is a developed cross-sectional view showing a driving device to which a power transmission device G2 for driving a valve according to an embodiment of the present invention is applied. Note that FIG. 1 is illustrated by appropriately expanding in the radial direction with priority given to the display of the meshing state of each gear, and the radial position (coordinates) in FIG. Are not necessarily consistent. 2 is a side view seen from the right direction of FIG. 1, FIG. 3 is a sectional view of the main part showing the configuration of the inscribed mesh planetary gear mechanism, and FIG. 4 is a side view seen from the left direction of FIG.
[0023]
The power transmission device G2 is used together with the motor 110, and includes a parallel shaft gear mechanism 112 and an intermeshing planetary gear mechanism 114 as a speed reduction mechanism.
[0024]
The motor shaft 126 of the motor 110 also serves as the input shaft of the parallel shaft gear mechanism 114. That is, the first pinion 128 of the parallel shaft gear mechanism 114 is formed on the motor shaft 126 by gear cutting.
[0025]
The parallel shaft gear mechanism 112 rotates together with the first gear 130 of the first gear reduction mechanism 132 including the first pinion 128, the first gear 130 meshing with the first pinion 128, and the first gear 130 of the first gear reduction mechanism 132. And a second-stage reduction mechanism 138 including a second gear (output gear) 136 that meshes with the second pinion 134. The configuration in the vicinity of the rotating shaft 190 that supports the first gear 130 and the second pinion 134 will be described in detail later.
[0026]
The second gear 136 of the second-stage reduction mechanism 138 is incorporated on the outer periphery of the input shaft 140 of the intermeshing planetary gear mechanism 114 and can rotate integrally with the input shaft 140.
[0027]
The intermeshing planetary gear mechanism 114 includes the input shaft 140, an eccentric body 142 integrated with the input shaft 140, and external teeth incorporated in a freely rotating manner on the outer periphery of the eccentric body 142 via a bearing 144. The gear 146 and the internal gear 148 having the number of teeth that is one more than the number of teeth of the external gear 146 (having a slight difference in the number of teeth) are included as components. The external gear 146 has a plurality of inner pin holes 146A, and the inner pins 152A integrated with the carrier 152 are loosely fitted in the inner pin holes 146A. The carrier 152 is connected (press-fitted) with the output shaft 150, whereby only the rotation component of the external gear 146 is transmitted to the output shaft 150 via the carrier 152. The output shaft 150 is formed with a bottomed hole 150A into which a part of the driven machine (not shown) can be engaged, and a part of the driven machine is connected to the output shaft 150 so that power can be transmitted. .
[0028]
Next, the arrangement configuration of each member of the power transmission device G2 including the configuration in the vicinity of the rotating shaft 190 will be described in detail.
[0029]
The casing 170 of the power transmission device G2 is integrally provided with a rectangular main body 174 and a substantially square protrusion 172 protruding from the main body 174 to the driven machine side (valve side), and is an aluminum-based lightweight material. Or it is formed by casting. The motor 110 is attached to the end 174 </ b> C of the main body 174.
[0030]
The projecting portion 172 of the casing 170 includes a mounting surface 172C for mounting the power transmission device G2 to a driven machine such as a valve via a bolt hole 172A or 172B, and the output of the intermeshing planetary gear mechanism 114. A hollow hole 172D for rotatably accommodating and supporting the end portion of the shaft 150 is provided.
[0031]
On the other hand, the main body 174 of the casing 170 accommodates the parallel shaft gear mechanism 112 and the inscribed mesh planetary gear mechanism 114 in a single space. As described above, FIG. 1 is a developed cross-sectional view, and the flange portions 174A and 174B of the main body portion 174 are actually present on the circumference having substantially the same radius from the axis O1 of the output shaft 150. A plate corresponding to the conventional plate 20 is not particularly provided.
[0032]
The outer periphery of the main body 174 also serves as the main body of the internal gear 148. The internal teeth of the internal gear 148 are rotatably incorporated into a groove 148B having a semicircular cross section having a roller-like pin 148A having higher hardness than the casing 170 itself (aluminum-based lightweight material or cast material). It is formed by. Accordingly, the tooth profile of the external gear 146 is a tooth profile based on a trochoidal curve.
[0033]
The outer periphery of the carrier 152 is slidably incorporated in the inner periphery 174D of the main body 174. The center portion 150B of the output shaft 150 is press-fitted on the inner periphery of the carrier 152, so that the rotation of the carrier 152 can be transmitted to the output shaft 150. The output shaft 150 is basically supported by the inner peripheral side 174D of the main body 174 via the hollow hole 172D of the protrusion 172 and the carrier 152. The output shaft 150 extends through the input shaft 140 of the intermeshing planetary gear mechanism 114 (with the eccentric body 142 integrated) to the parallel shaft gear mechanism 112 side, and is input via the needle bearing 180. The shaft 140 is mutually supported.
[0034]
On the other hand, a plate 182 is attached to one end side of the main body 174 via bolts 186. Bearing portions 192 and 194 of the rotary shaft 190 on which the first gear 130 and the second pinion 134 of the parallel shaft gear mechanism 112 are mounted are disposed on the flange portion 174B of the plate 182 and the main body portion 174, respectively.
[0035]
Of the bearing portions 192 and 194, the bearing portion 194 on the main body portion 174 side is within the outer periphery of the internal gear 148, that is, within the axial range L where the internal gear 148 exists (see FIG. 1) and the internal teeth. It arrange | positions in the position of the radial direction outer side of the gearwheel 148 (refer FIG. 6). This position is thick in the radial direction and corresponds to a position where the highest strength can be secured in the casing 170. FIG. 6 is a combination of both diagrams to show the positional relationship between FIG. 2 and FIG.
[0036]
Referring to FIG. 1 again, as a result, the main portion of the intermeshing planetary gear mechanism 114 including the input shaft 140, the external gear 146, the internal gear 148 and the like and the bearing portion 194 have substantially the same axial coordinate. It will be arranged in a plane.
[0037]
A wide space S is secured on the right side of the plate 182 in FIG. 1, and an auxiliary machine (control device or the like) for controlling a motor such as an encoder can be incorporated in this space S.
[0038]
As shown in FIGS. 2 and 5, the second pinion 134 meshes with the second gear 136 of the parallel shaft gear mechanism 112, and the manual pinion 160 meshes simultaneously. Here, FIG. 5 is a cross-section taken along the point AB in FIG. The second gear 136 can be rotated by rotating the manual shaft 162 that supports the manual pinion 160 when the motor 110 is replaced or when the electric system is defective.
[0039]
In the figure, reference numeral 195 denotes a retaining ring, 196 denotes a spacer, and 197 denotes an outer cover.
[0040]
Next, the operation of this power transmission device will be described.
[0041]
When the motor shaft 110 rotates, two-stage deceleration is performed via the first pinion 128, the first gear 130, the second pinion 134, and the second gear 136 of the parallel shaft gear mechanism 112, and the second gear 136 The input shaft 140 of the intermeshing planetary gear mechanism 114 engaged on the inner peripheral side rotates. As a result, the external gear 146 oscillates and rotates while inscribed in the internal gear 148 via the eccentric body 142 integrated with the input shaft 140, and the external gear 146 is rotated every time the input shaft 140 rotates. The motor rotates slowly by an amount corresponding to a slight difference in the number of teeth (1 in this example) between the tooth gear 148 and the external gear 146. The movement of the external gear 146 is absorbed by the loose fit of the inner pin hole 146 A and the inner pin 152 A, and only the rotation component is transmitted to the output shaft 150 via the carrier 152. The rotation of the output shaft 150 is further transmitted to a driven machine (not shown) that is engaged in the bottomed hole 150A.
[0042]
In addition, as the internal meshing planetary gear mechanism having an external gear and an internal gear having a slight difference in the number of teeth, other types such as “flexion meshing type” or “differential gear type” are known. is there. In either case, a large reduction ratio can be obtained in one stage.
[0043]
Here, since the bearing portion 194 of the rotating shaft 190 that rotatably supports the first gear 130 and the second pinion 134 of the parallel shaft gear mechanism 112 is disposed on the outer periphery of the internal gear 148, the bearing portion 194 is supported in an extremely stable state, and the rotating shaft 190 can be smoothly rotated.
[0044]
In addition, since the bearing portion 194 is disposed in substantially the same plane as the plane in which the main part of the internal mesh planetary gear mechanism 114 including the external gear 146 and the internal gear 148 exists, the power transmission device G2 The overall axial length can be shortened accordingly.
[0045]
Furthermore, since the arrangement of the plate 20 or the like that has been conventionally required can be omitted, the weight can be reduced accordingly, and the axial length of the power transmission device G2 can be further reduced accordingly.
[0046]
Further, since the outer periphery of the main body 174 of the casing 170 also serves as the main body of the internal gear 148, the number of parts can be reduced, and the entire casing including the internal gear 148 is made of a lightweight aluminum material. Therefore, the weight is reduced also in this respect. On the other hand, since the tooth profile of the internal gear 148 is composed of a roller-shaped pin 148A having a hardness higher than that of the main body, high durability can be obtained particularly with respect to meshing with the external gear 146. it can. Note that the contact between the pin 148A of the internal gear 148 and the groove 148B is a contact between a convex and a concave, and is excellent in durability.
[0047]
The output shaft 150 is stably supported by the hollow hole 172A of the projecting portion 172 of the casing 170 and the inner periphery 174D of the main body portion 174 (via the carrier 152), and has an input that is long in the axial direction via the needle bearing 180. The shaft 140 is fitted. Therefore, the right end of the output shaft 150 of the casing 170 in FIG. 1 is released from the output shaft, and the output shaft can be stably supported and rotated even if the right end of the output shaft is not particularly supported by the casing 170. It is. In other words, with this configuration, a bearing (on the right end side) for supporting the output shaft 150 on the casing 170 can be omitted, and accordingly, the cost can be reduced and the axial direction can be shortened.
[0048]
Further, when the motor cannot be driven for some reason, the manual gear 160 engaged with the second gear 136 of the parallel shaft gear mechanism 112 is rotated via the manual shaft 162 as shown in FIG. The second gear 136 can be rotated. As a result, the driven machine can be driven manually by an extremely light operation as much as the intermeshing planetary gear mechanism 114 is interposed.
[0049]
FIG. 7 shows an application example of another embodiment of the present invention. In this power transmission device G3, as a configuration of the parallel shaft gear mechanism 212, a one-stage reduction mechanism substantially constituted by the third pinion 228 and the fourth gear 236 is adopted, and the third pinion 228 and the fourth pinion 228 The gear 236 is connected by an idle gear 231. A bearing portion 294 of the rotary shaft 290 that supports the idle gear 231 is disposed on the “outer periphery” of the internal gear 248.
[0050]
Further, in the power transmission device G4 shown in FIG. 8, the parallel shaft gear mechanism 312 is substantially constituted by the fifth pinion 328 and the sixth gear 336 geared to the outer periphery of the input shaft 340 of the intermeshing planetary gear mechanism 314. A single-stage reduction mechanism configured is employed, and the fifth pinion 328 and the sixth gear 336 are connected by a large-diameter idle gear 331. A bearing portion 394 of the rotating shaft 390 supporting the idle gear 331 is disposed on the “outer periphery” of the internal gear 348.
[0051]
In the examples of FIGS. 7 and 8, the other configurations are basically the same as those of the embodiment already described.
[0052]
Due to such deformation, the design of the intermeshing planetary gear mechanism on the side of the intermeshing planetary gear mechanism, which is complicated and expensive to handle jigs and tools due to the change of the tooth profile, is almost unchanged, and only the low-cost parallel shaft gear mechanism is used. By changing, the total reduction ratio of the power transmission device can be easily adjusted.
[0053]
In any of the embodiments, the rotation shafts 190, 290, 390 of the parallel shaft gear mechanisms 112, 212, 312 are arranged on the “outer periphery” of the internal gears 148, 248, 348. The effect as described above can be obtained in exactly the same manner.
[0054]
【The invention's effect】
According to the present invention, the parallel shaft gear mechanism and the intermeshing planetary gear mechanism are arranged in a rationally fused structure, so that the support rigidity of each gear mechanism can be enhanced and the weight can be reduced. The direction can be made compact.
[Brief description of the drawings]
FIG. 1 is a developed longitudinal sectional view of a drive device showing an application example of an embodiment of a power transmission device to which the present invention is applied. FIG. 2 is a side view seen from the right side of FIG. FIG. 4 is a cross-sectional view of the main part showing the configuration of the gear mechanism. FIG. 4 is a side view as viewed from the left in FIG. 7 is a longitudinal sectional view corresponding to FIG. 1 showing an application example of another embodiment of the present invention. FIG. 8 is a longitudinal sectional view corresponding to FIG. 1 showing an application example of still another embodiment of the present invention. 1 is a longitudinal sectional view corresponding to FIG. 1 showing an application example of a conventional power transmission device.
DESCRIPTION OF SYMBOLS 110 ... Motor 112 ... Parallel shaft gear mechanism 114 ... Internal meshing planetary gear mechanism 128 ... 1st pinion 130 ... 1st gear 132 ... 1st stage reduction mechanism 134 ... 2nd pinion 136 ... 2nd gear (output gear)
138 ... Second stage reduction mechanism 140 ... Input shaft 142 of internal meshing planetary gear mechanism ... Eccentric body 144 ... Bearing 146 ... External gear 148 ... Internal gear 150 ... Output shaft 152 ... Carrier 160 ... Manual pinion 162 ... Manual shaft 170 ... Casing 172 ... Projection 174 ... Main body 190 ... Rotating shaft 194, 196 ... Bearing L ... Axial range in which internal gears exist

Claims (3)

In a power transmission device for driving a valve, comprising: a parallel shaft gear mechanism; and an internal mesh planetary gear mechanism including an external gear and an internal gear having a slight difference in the number of teeth;
A casing that accommodates the internally meshing planetary gear mechanism, wherein at least one of the bearing portion for supporting the rotation of the parallel shaft gear mechanism of the gear, but the range of the axial direction in which the internal gear is present, and Arranged at a position radially outward of the internal gear,
The internal gear has a main body and a tooth-shaped portion;
A power transmission device for driving a valve, wherein the casing and the main body of the internal gear are integrated . The power transmission device for driving a valve according to claim 1, wherein the tooth profile of the internal gear is composed of a semicircular groove and a roller-like pin rotatably engaged with the groove. . The power transmission device for driving a valve according to claim 2, wherein the hardness of the material of the pin is higher than the hardness of the material of the main body of the internal gear.

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