JP4913679B2 - Reducer and method for adjusting backlash in reducer - Google Patents

Description

  The present invention relates to a speed reducer using a locked train and a method for adjusting backlash in the speed reducer.

The speed reducer distributes the torque of a single input shaft to a plurality of intermediate shafts by a first gear train, and this intermediate shaft torque is arranged on the same axis as the input shaft by a second gear train. One utilizing a locked train that is transmitted to one output shaft is known.
In such a reducer, the balance of torque distribution to each intermediate shaft is likely to be lost due to dimensional errors, assembly errors, backlash, etc. of the casing and gears, etc., resulting in noise and vibration not being transmitted smoothly. Become.
As a countermeasure, for example, in Patent Documents 1 and 2, the intermediate shaft is movable in the axial direction, and hydrostatic bearings formed by narrow gaps to which pressure oil is supplied are provided at both ends thereof, and the intermediate shaft is thrust. An invention has been disclosed in which it is elastically supported in the direction to absorb the cumulative pitch error of the gears and the like, and the load is evenly distributed to each intermediate shaft.

Japanese Patent Laid-Open No. 58-1113650 JP 58-88247 A

  However, in the structures of Patent Documents 1 and 2, it is necessary to newly provide an additional mechanism such as a hydrostatic bearing for the intermediate shaft and a hydraulic circuit in the speed reducer, resulting in a complicated overall structure and an increase in cost. .

  Therefore, the present invention has an object to provide a speed reducer that can realize smooth torque transmission with a simple structure that does not include an additional mechanism, and a backlash adjustment method that provides such a speed reducer. It is.

In order to achieve the above-mentioned object, the invention according to claim 1 includes an input shaft having an input pinion in the front and an input gear meshing with the input pinion in the casing, and an output pinion in front of the input gear. An input pinion comprising a plurality of intermediate shafts parallel to the input shaft, and an output gear having an output gear meshing with each output pinion of the intermediate shaft, and supporting the output shaft coaxially with the input shaft input gear and the backlash of the meshing portion between the input gear of each intermediate shaft, and a backlash of the meshing portion between the output pinion and the output gear of the intermediate shaft, Rutotomoni substantially matched between each intermediate shaft mutually, and the input pinion The backlash of the meshing portion with each other is 1 minute or less, and the backlash of the meshing portion between the output pinion and the output gear is 2 minutes or less , respectively.
Invention according to claim 2, in addition to the purpose of claim 1, in order to streamline journalled structure between the output shaft and the input shaft, the input shaft, the output shaft projecting forward from the input pinion A small-diameter portion to be inserted into the rear portion is formed, and the small-diameter portion is pivotally supported in the rear portion of the output shaft. The thrust shaft bearing is interposed so that the input shaft bearing receives the load on the rear side of the input shaft and the output shaft, and the output shaft bearing receives the load on the front side of the input shaft and the output shaft. It is a feature.

In order to achieve the above-mentioned object, the invention according to claim 3 includes an input shaft having an input pinion in the casing and an input gear meshing with the input pinion in the casing, and an output pinion in front of the input gear. Backlash is adjusted in a speed reducer that includes a plurality of intermediate shafts parallel to the input shaft and an output gear that meshes with each output pinion of the intermediate shaft, and that supports the input shaft and an output shaft that is positioned coaxially. A tooth thickness of each pinion and gear, a center distance between the bearing hole of the input shaft in the casing and the bearing hole on the rear end side of the intermediate shaft, and the bearing hole of the output shaft and the intermediate shaft in the casing. Dimensional evaluation is performed at each center distance with the front end bearing hole and the opening diameter of the bearing hole before and after the intermediate shaft, and by using the parts selected through the dimensional evaluation, the input pinion and each intermediate shaft Input And backlash of the meshing portion between Ya, backlash of the meshing portion between the intermediate shaft output pinion and the backlash of the meshing portion of the output gear, causes substantially matched between each intermediate shaft mutually, the input pinion and the input gear The backlash of the meshing part of the output pinion and the output gear is 2 minutes or less , respectively.

According to the first and third aspects of the present invention, a highly accurate reduction gear can be obtained with a simple structure in which no additional mechanism is provided by substantially matching backlash of the meshing portion. Therefore, smooth torque transmission can be realized at low cost.
Further , the overall backlash is 3 minutes or less, and the reduction gear is more accurate.
According to the second aspect of the present invention, in addition to the effect of the first aspect , the thrust bearing is interposed between the input shaft and the output shaft so that the thrust load on both shafts is received by the front and rear bearings, respectively. As a result, there is no need to newly provide a casing wall between the input shaft and the output shaft to support the shaft, thereby streamlining the structure and contributing to cost reduction. Further, since the shaft support portion by the casing can be omitted, the backlash adjustment is not affected.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing an example of a speed reducer. The speed reducer 1 includes a single input shaft 3 and a pair of intermediate shafts 4 and 4 that transmit torque from the input shaft 3 in a casing 2. A locked train provided with a single output shaft 5 which is transmitted with torque from the intermediate shafts 4 and 4 and is arranged coaxially with the input shaft 3 is employed. First, the casing 2 is constituted by connecting a connecting casing 6 connected to a motor, a gear bracket 7 and a gear casing 8 from the rear (left side in FIG. 1) with bolts 9, 9,. An input pinion 12 that is pivotally supported by a ball bearing 10 provided in the connection casing 6 and formed in front of the connection casing 6 passes through the gear bracket 7 and projects into the gear casing 8. 11 is an oil seal. An output shaft of a motor assembled to the connection casing 6 can be connected to the rear end of the input shaft 3. In addition, a shaft-shaped small-diameter portion 13 having a diameter smaller than the outer diameter of the input pinion 12 is coaxially provided in front of the input pinion 12.

  The intermediate shaft 4 is integrally press-fitted to the rear end of an input gear 14 that meshes with the input pinion 12 of the input shaft 3, and an output pinion 15 is formed in front of the input gear 14. While being supported by a ball bearing 16 provided on the gear bracket 7, the front end is supported by a needle bearing 17 provided on the gear casing 8. 18 and 18 are disc springs disposed behind the ball bearing 16 in a bearing hole 19 that accommodates the ball bearing 16 in the gear bracket 7, and serve to suppress the rattling by urging the intermediate shaft 4 forward. Plays.

  Further, the output shaft 5 is formed with an output gear 20 that meshes with the output pinions 15 and 15 of the intermediate shafts 4 and 4 at the rear end, and the front end protrudes forward from the gear casing 8. The needle bearing 21 is rotatably supported. A receiving plate 23 with a plurality of balls 22, 22... Is provided behind the needle bearing 21 and is in contact with the front surface of the output gear 20. Therefore, the needle bearing 21 receives a load in the direction in which the output shaft 5 is pulled forward.

On the other hand, a bottomed hole 24 into which the small-diameter portion 13 of the input shaft 3 is loosely inserted coaxially is formed at the rear axis of the output shaft 5, and the small-diameter portion 13 is pivoted by a needle bearing 25 provided in the bottomed hole 24. I support. Further, a thrust bearing 26 through which the small-diameter portion 13 passes is interposed between the front end surface of the input pinion 12 of the input shaft 3 and the rear end surface of the output shaft 5, and a load to the rear side of the output shaft 5 is input. It is transmitted to the ball bearing 10 via the shaft 3.
Here, as shown in FIG. 2, the gear casing 8 is provided with an accommodating space 30 having an elliptical cross section in one diagonal direction, and the intermediate shafts 4 and 4 are connected to the input shaft 3 and the output shaft 5, respectively. They are arranged so as to be point-symmetric on the diagonal line at the center. Thereby, the casing 2 can be made compact.

In the reduction gear 1, the backlash is adjusted by using the selected parts after evaluating the dimensions of each part affecting the backlash. Here, the following parts and their dimensions are evaluated.
(1) Tooth thickness of the input pinion 12 and the input gears 14 and 14 (2) Tooth thickness of the output pinion 15 and 15 and the output gear 20 (3) Fitting portion 7a (here circular) of the gear bracket 7 with the connecting casing 6 Center distance between the projections) and the bearing holes 19 of the two ball bearings (4) a fitting portion 6a (here circular recess) with the gear bracket 7 in the connecting casing 6, and a bearing hole of the ball bearing 10 (5) Gap between fitting portion 6a and fitting portion 7a (6) Bearing hole 28 for accommodating needle bearing 21 in gear casing 8 and the front end of intermediate shaft 4 Center distance of each of the needle bearings 17 and the bearing hole 29 (7) Diameter of the bearing holes 19 and 29 Dimensional evaluation is performed in each of these items, and the first stage (two input pinions 12 and two The gears and casings are selected so that the meshing of the input gears 14 and 14) is less than 1 minute of backlash and the meshing of the second stage (the two output pinions 15 and 15 and the output gear 20) is less than 2 minutes of backlash, respectively. By doing so, the backlash between the intermediate shafts 4 is matched in the front and rear directions. Thereby, the whole backlash can be suppressed to 3 minutes or less.

Specifically, in the first stage, the circumferential backlash St between the input gear 14 and the input pinion 12 is calculated from the center distance direction backlash Sr and the tooth perpendicular pressure angle α.
St = 2 ・ Sr ・ tanα
Is calculated by Here, assuming that the tooth thickness errors (error values from the reference value) of the input gear 14 are Ea and Eb, the backlash Es during assembly is
Es = Ea + Eb + St
It becomes.
Similarly, also in the second stage, the circumferential backlash St ′ between the output gear 20 and the output pinions 15 and 15 is obtained, and the respective tooth thickness errors (error values from the reference value) of the output pinion 15 are represented by Ea ′, Assuming Eb ', the backlash Es' during assembly is
Es ′ = Ea ′ + Eb ′ + St ′
It becomes.
Accordingly, the gear and the casing are selected so that the two Ess have the same value and the Ess have the same value in the two intermediate shafts 4.

  Thus, according to the speed reducer 1 and the backlash adjustment method of the above embodiment, in the speed reducer 1 using a locked train, the tooth thickness of each pinion and gear, the fitting portion 7a of the gear bracket 7, and the bearing hole 19, the center distance between the fitting portion 6 a of the connection casing 6 and the bearing hole 27, the opening diameter of the bearing hole 27, the gap between the fitting portion 6 a and the fitting portion 7 a, and the gear casing. 8, each of the center distance between the bearing hole 28 of the output shaft 5 and the bearing hole 29 on the front end side of the intermediate shaft 4 and the opening diameters of the bearing holes 19 and 29 before and after the intermediate shaft 4 are evaluated. Using the parts selected through the dimensional evaluation, the backlash of the meshing portion between the input pinion 12 and the input gear 14 of each intermediate shaft 4, and the output pinion 15 of each intermediate shaft 4 and the output gear 20 of the output shaft 5 Back of the meshing part And Tsu Shi, it was substantially matched between each intermediate shaft 4 mutually, a simple structure without the additional mechanism, reduction gear 1 is obtained with high accuracy. Therefore, smooth torque transmission can be realized at low cost.

In particular, the backlash of the meshing portion between the input pinion 12 and the input gear 14 is approximately equal to 1 minute or less, and the backlash of the meshing portion between the output pinion 15 and the output gear 20 is approximately equal to 2 minutes or less. The backlash is 3 minutes or less, and the reduction gear 1 with higher accuracy is obtained.
Further, the input shaft 3 is formed with a small-diameter portion 13 that protrudes forward from the input pinion 12 and is inserted into the rear portion of the output shaft 5. The small-diameter portion 13 is pivotally supported in the rear portion of the output shaft 5, and input Between the front end face of the input pinion 12 and the rear end face of the output shaft 5 in the shaft 3, a ball bearing 10 through which the small diameter portion 13 passes is interposed so that the ball bearing 10 of the input shaft 3 moves to the rear side of the input shaft 3. Since the needle bearing 21 of the output shaft 5 receives the load on the front side of the output shaft 5, a casing wall is provided between the input shaft 3 and the output shaft 5 to support the load. This eliminates the need for the structure and contributes to cost reduction. Further, since the shaft support portion by the casing can be omitted, the backlash adjustment is not affected.

  In addition, the division | segmentation aspect of a casing, the kind of bearing, etc. are not restricted to the said form, It can change suitably. In particular, in the above embodiment, since the casing is divided into the connecting casing 6 and the gear bracket 7 and positioned by the fitting portions 6a and 7a, the fitting portion 6a on the connecting casing 6 side and the bearing hole 27 of the input shaft 3 The center distance between the fitting portion 7a on the gear bracket 7 side and the bearing hole 19 on the rear end side of the intermediate shaft 4 and the gap between the fitting portions 6a and 7a are subject to dimensional evaluation. As a result, the center distance between the bearing hole 27 of the input shaft 3 and the bearing hole 19 on the rear end side of the intermediate shaft 4 is indirectly evaluated, but the casing is divided into a connection casing and a gear bracket. If not, the center distance between the bearing hole 27 and the bearing hole 19 may be directly dimensionally evaluated.

On the other hand, the number of intermediate shafts is not limited to two, and three or more intermediate shafts may be provided. Also, the thrust bearing between the input shaft and the output shaft can be omitted.
Moreover, in the said form, although the spur gear is used for each pinion and a gear, it may replace with other types, such as a helical gear, and may use together a different combination separately. Note that the circumferential backlash St when the helical gear is used is obtained by using the front pressure angle αt and the twist angle β.
αt = tan ⁻¹ (tan α / cos β)
After calculating with the formula of
What is necessary is just to obtain | require by the formula of St = 2 * Sr * tan (alpha) t.

In addition, other urging means such as a plate spring or a coil spring may be employed instead of the disc spring, or the urging means may be omitted.

It is a longitudinal cross-sectional view of a reduction gear. It is a cross-sectional view of a gear casing part.

Explanation of symbols

  1 .... reducer, 2. casing, 3. input shaft, 4. intermediate shaft, 5. output shaft, 6. connection casing, 7. gear bracket, 6a, 7a ... fitting part, 8 .. Gear casing 10, 16... Ball bearing, 12 .. Input pinion, 13 .. Small diameter part, 14 .. Input gear, 15 .. Output pinion, 17, 21, 25. 27 to 29 .. Bearing hole, 20 .. Output gear, 24 .. Bottomed hole, 26 .. Thrust bearing, 30.

Claims (3)

An input shaft having an input pinion in front of the casing, an input gear meshing with the input pinion and having an output pinion in front of the input shaft, a plurality of intermediate shafts parallel to the input shaft, and the intermediate shaft A reduction gear comprising an output gear meshing with each output pinion and pivotally supporting the input shaft and an output shaft located coaxially,
The input pinion and the backlash of the meshing portion between the input gear of each intermediate shaft, wherein the backlash of the meshing portion between the output pinion and the output gear of the intermediate shaft, Rutotomoni substantially matched between each said intermediate shaft mutually, The reduction gear according to claim 1, wherein the backlash of the meshing portion between the input pinion and the input gear is 1 minute or less and the backlash of the meshing portion between the output pinion and the output gear is 2 minutes or less, respectively. The input shaft is formed with a small-diameter portion that protrudes forward from the input pinion and is inserted into the rear portion of the output shaft, and the small-diameter portion is pivotally supported in the rear portion, and the front end surface of the input pinion in the input shaft Between the rear end surface of the output shaft, a thrust bearing through which the small diameter portion passes is interposed,
The bearing of the input shaft receives a load on the rear side of the input shaft and the output shaft, and the bearing of the output shaft receives a load on the front side of the input shaft and the output shaft, respectively. Item 1. A reduction gear according to item 1 . An input shaft having an input pinion in front of the casing, an input gear meshing with the input pinion and having an output pinion in front of the input shaft, a plurality of intermediate shafts parallel to the input shaft, and the intermediate shaft In a reduction gear comprising an output gear meshing with each output pinion and pivotally supporting the input shaft and an output shaft positioned coaxially, a method for adjusting backlash,
The tooth thickness of each pinion and gear, the center distance between the bearing hole of the input shaft and the bearing hole on the rear end side of the intermediate shaft in the casing, the bearing hole of the output shaft and the intermediate shaft of the casing Dimensional evaluation is performed at each center distance with the bearing hole on the front end side and the opening diameter of the bearing hole before and after the intermediate shaft, and by using the parts selected through the dimensional evaluation, the input pinion and each The backlash of the meshing portion with the input gear of the intermediate shaft and the backlash of the meshing portion of the output pinion and the output gear of each intermediate shaft are substantially matched between the intermediate shafts , and the input pinion and the input gear in reduction gear, wherein the engagement portion backlash respectively 1 minute or less, to the respective 2 minutes or less backlash meshing portion between the output pinion and the output gear and Kkurasshi adjustment method.

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