JP6588372B2 - Gear device - Google Patents

Description

  The present invention relates to a gear device.

  A through hole is provided in the casing of the gear device, and the shaft is supported via a bearing disposed in the through hole. A lid for closing the through hole is attached to the casing.

JP 2013-139842 A

  The gear unit bearing requires lubrication. There are two types of liquid lubricant (hereinafter also referred to as “lubricating oil”) supplied to the bearings, one using a pump and the other using no pump. In the latter case, since the circulation of the lubricating oil is not assisted by power, the supply of the lubricating oil may be insufficient depending on the installation direction of the gear device and the arrangement of the bearings.

  This invention is made | formed in view of such a condition, The objective is to provide the gear apparatus which enables appropriate lubrication of a bearing.

  According to an aspect of the present invention, the gear device is a casing having a gear housing space and capable of containing a liquid lubricant, the first bearing hole penetrating the casing into the gear housing space, and the first gear hole. A casing including a first bearing hole cover for closing the bearing hole, and a buffer tank connected to the gear storage space and capable of receiving a liquid lubricant from the gear storage space. The buffer tank is connected to a first cover inner space inside the first bearing hole cover, and is capable of receiving air from the first cover inner space.

  ADVANTAGE OF THE INVENTION According to this invention, the gear apparatus which enables the appropriate lubrication of a bearing can be provided.

It is a perspective view which shows the external appearance of the gear apparatus which concerns on a certain embodiment. It is a figure which shows roughly the internal structure of the gear apparatus shown in FIG. It is a figure which expands and shows a part of FIG. It is the schematic which shows the upper surface of the gear apparatus shown in FIG. The 1st bearing hole cover and communication path concerning an embodiment are shown.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. The same or equivalent components, members, and processes shown in the drawings are denoted by the same reference numerals, and redundant descriptions are omitted as appropriate. The dimensions of the members in each drawing can be appropriately enlarged or reduced for easy understanding. In the drawings, some of the members that are not important for describing the embodiment may be omitted. Moreover, the structure described below is an illustration and does not limit the scope of the present invention at all.

  FIG. 1 is a perspective view showing an appearance of a gear device 10 according to an embodiment. FIG. 2 schematically shows an internal structure of gear device 10 shown in FIG. FIG. 3 is an enlarged view of a part of FIG. FIG. 4 is a schematic view showing an upper surface of the gear device 10 shown in FIG.

  The gear device 10 includes a casing 12 and a buffer tank 14 with an air vent mechanism (hereinafter also simply referred to as a buffer tank). The casing 12 has a gear storage space 16 inside, and can enclose lubricating oil in the gear storage space 16. The buffer tank 14 can receive lubricating oil and air, and can store lubricating oil. The buffer tank 14 is attached to the casing 12 by an attachment member (not shown).

  Further, the gear device 10 includes a lubricant circulation pipe (hereinafter also simply referred to as a circulation pipe) 18, a first communication pipe 20, a second communication pipe 22, and a third communication pipe as pipes that connect the casing 12 to the buffer tank 14. 24. The circulation pipe 18 connects the gear housing space 16 to the buffer tank 14. The circulation pipe 18 includes a recovery pipe 18 a for receiving lubricating oil overflowing from the gear housing space 16 to the buffer tank 14, and a return pipe 18 b for returning lubricating oil from the buffer tank 14 to the gear housing space 16. Details of the first communication pipe 20, the second communication pipe 22, and the third communication pipe 24 will be described later.

  The gear device 10 is an orthogonal reduction device, and includes an input shaft (high speed shaft) 28 and an output shaft (low speed shaft) 30 orthogonal thereto. The gear device 10 includes a first shaft 32, a second shaft 34, and a third shaft 36 as intermediate shafts. These intermediate shafts are parallel to the output shaft 30. The shaft diameters of the first shaft 32, the second shaft 34, the third shaft 36, and the output shaft 30 are thicker in this order. Alternatively, two adjacent axes (for example, the first axis 32 and the second axis 34) may have the same diameter. Further, the shaft on the input side may be thicker than the shaft on the output side.

  Each of the input shaft 28, the output shaft 30, the first shaft 32, the second shaft 34, and the third shaft 36 has a gear housed in the gear housing space 16. The input shaft 28 includes a first bevel gear 28a at the end. The first shaft 32 includes a second bevel gear 32a that meshes with the first bevel gear 28a, and a first pinion 32b. The second shaft 34 includes a first gear 34a that meshes with the first pinion 32b, and a second pinion 34b. The third shaft 36 includes a second gear 36a that meshes with the second pinion 34b, and a third pinion 36b. The output shaft 30 includes a third gear 30a that meshes with the third pinion 36b. The rotation of the input shaft 28 is decelerated by such a gear train and transmitted to the output shaft 30.

  The casing 12 has a first casing surface 12a and a second casing surface 12b. The second casing surface 12b is on the opposite side of the first casing surface 12a with the gear housing space 16 in between. The first casing surface 12a and the second casing surface 12b can each be installed on an arbitrary installation surface such as a floor surface or an installation surface of another device. There can be various orientations of the installation surface. The installation surface may be a horizontal surface, a vertical surface, or another inclined surface.

  For installation, the first casing surface 12a is provided with a first leg portion 38a, and the second casing surface 12b is provided with a second leg portion 38b. The first leg portion 38a or the second leg portion 38b is attached to the installation surface by a fastener such as a bolt, and thus the gear device 10 is fixed to the installation surface.

  1 and 2 show a state where the first casing surface 12a is installed on a horizontal installation surface as an installation example of the gear device 10. FIG. In this case, the second casing surface 12b is positioned vertically above the first casing surface 12a. The first casing surface 12 a corresponds to the lower surface of the casing 12, and the second casing surface 12 b corresponds to the upper surface of the casing 12. The input shaft 28 is oriented in the horizontal direction. The output shaft 30 extends from the first casing surface 12a and is directed downward in the vertical direction. Installation in which the output shaft 30 is directed in the vertical direction in this way is also referred to as “vertical installation (vertical installation)”. Installation in which the output shaft 30 is directed upward in the vertical direction is also included in the vertical placement.

  The casing 12 may have legs on another casing surface, and the casing 12 may be installed on the installation surface. For example, the casing 12 may have legs on the back surface of the casing 12 (not shown in FIG. 1), and the gear device 10 may be installed with the output shaft 30 oriented in the horizontal direction (this is “horizontal installation”). Also called).

  In this document, the term “vertical installation” (or “horizontal installation”) does not require that the output shaft 30 exactly match the vertical direction (or horizontal direction). The output shaft 30 may be tilted somewhat from the vertical direction (or horizontal direction). In other words, it should be understood that the term vertical (or horizontal) does not necessarily mean only exact vertical (or horizontal). In other words, it can be said that the first casing surface 12a is installed on the installation surface and the second casing surface 12b is positioned vertically above the first casing surface 12a.

  The casing 12 is roughly divided into two parts, a part on the input shaft 28 side and a part on the output shaft 30 side, and the external dimensions on the input shaft 28 side are slightly smaller than those on the output shaft 30 side. Therefore, the casing 12 has a step portion 13 between a portion on the input shaft 28 side and a portion on the output shaft 30 side.

  The casing 12 has a first bearing hole 40, a second bearing hole 42, a third bearing hole 44, and a fourth bearing hole 46 in each of the first casing surface 12a and the second casing surface 12b. These bearing holes are arranged in a line between the input shaft 28 and the buffer tank 14. All of the four bearing holes penetrate the casing 12 to the gear housing space 16. A first bearing 41, a second bearing 43, a third bearing 45, and a fourth bearing 47 are disposed in the first bearing hole 40, the second bearing hole 42, the third bearing hole 44, and the fourth bearing hole 46, respectively. Has been. The diameters of the first bearing hole 40, the second bearing hole 42, the third bearing hole 44, and the fourth bearing hole 46 increase in this order. Alternatively, two adjacent shaft hole shafts (for example, the first bearing hole 40 and the second bearing hole 42) may have the same diameter. The input-side bearing hole may have a larger diameter than the output-side bearing hole.

  The casing 12 includes a first bearing hole cover 50, a third bearing hole cover 54, and a fourth bearing hole cover 56. Each of these covers is attached to the casing 12. Similarly to the bearing hole, the bearing hole cover is also arranged in a line between the input shaft 28 and the buffer tank 14. In addition, the shafts and the bearing holes may be arranged so as not to be arranged in a line. In this case, the bearing hole covers are not arranged in a line.

  The first bearing hole cover 50 has a first recess 50 a facing the first bearing hole 40 and a second recess 50 b facing the second bearing hole 42 on the inner surface thereof. The third bearing hole cover 54 has a third recess 54 a facing the third bearing hole 44 on the inner side. The fourth bearing hole cover 56 has a fourth recess 56 a facing the fourth bearing hole 46 on the inner side.

  The first bearing hole cover 50 is a single cover for the first bearing hole 40 and the second bearing hole 42 and closes both the first bearing hole 40 and the second bearing hole 42. A first cover inner space 51 is formed inside the first bearing hole cover 50 corresponding to the first bearing hole 40, and a second cover inner space 52 is formed corresponding to the second bearing hole 42. The The distance between the first shaft 32 and the second shaft 34 is relatively small. By making the covers of the corresponding two bearing holes in common, the cover can be attached more easily than when individual covers are prepared for the two shafts.

  The first bearing hole cover 50 includes a communication passage 53 that communicates the second cover inner space 52 with the first cover inner space 51. The communication path 53 is a groove or a hole formed in the partition wall of the first bearing hole cover 50 that partitions the first cover inner space 51 and the second cover inner space 52.

  The third bearing hole cover 54 closes the third bearing hole 44. A third cover inner space 55 is formed inside the third bearing hole cover 54 so as to correspond to the third bearing hole 44. The fourth bearing hole cover 56 closes the fourth bearing hole 46. A fourth cover inner space 57 is formed inside the fourth bearing hole cover 56 so as to correspond to the fourth bearing hole 46. The third bearing hole cover 54 and the fourth bearing hole cover 56 are disk-shaped, and the fourth bearing hole cover 56 has a larger diameter than the third bearing hole cover 54. Note that the outer shape of each bearing hole cover is not particularly limited to a circle, and various shapes can be adopted, and the size relationship between the bearing hole covers is not particularly limited.

  The first shaft 32, the second shaft 34, the third shaft 36, and the output shaft 30 are housed in the first bearing hole 40, the second bearing hole 42, the third bearing hole 44, and the fourth bearing hole 46, respectively. It extends from the space 16. An extending portion of the first shaft 32 is supported by a first bearing 41 disposed in the first bearing hole 40. Similarly, the second shaft 34, the third shaft 36, and the output shaft 30 are respectively supported by a second bearing 43, a third bearing 45, and a fourth bearing 47 that are disposed in each bearing hole.

  The first end surface 32 c of the first shaft 32 faces the first cover inner space 51, and the second end surface 34 c of the second shaft 34 faces the second cover inner space 52. Similarly, the third end surface 36 c of the third shaft 36 faces the third cover inner space 55. An end surface 30 b on the second casing surface 12 b side of the output shaft 30 faces the fourth cover inner space 57.

  The output shaft 30 extends through the fourth bearing hole cover 56 on the first casing surface 12a side. The fourth bearing hole cover 56 on the first casing surface 12a side has a fourth cover through hole 56b through which the output shaft 30 passes. A part 30 c of the side surface of the output shaft 30 on the first casing surface 12 a side faces the fourth cover inner space 57. A portion 30c of the output shaft 30 is a portion between the fourth bearing hole 46 and the fourth cover through hole 56b.

  The buffer tank 14 has a first buffer tank surface 14a and a second buffer tank surface 14b. The first buffer tank surface 14a faces the first casing surface 12a (the same direction as the first casing surface 12a), and the second buffer tank surface 14b faces the second casing surface 12b (the second casing surface 12b and Facing the same direction). In the case of vertical installation, the first buffer tank surface 14 a corresponds to the lower surface of the buffer tank 14, and the second buffer tank surface 14 b corresponds to the upper surface of the buffer tank 14. The second buffer tank surface 14 b is arranged farther from the first casing surface 12 a than the first bearing hole 40.

  The height from the first casing surface 12a to the first buffer tank surface 14a is substantially equal to the height from the first casing surface 12a to the second casing surface 12b. Thus, the first buffer tank surface 14a is positioned at substantially the same height as the bearing hole on the second casing surface 12b side.

  FIG. 2 illustrates the initial liquid level height H of the lubricating oil. Most or all of the gear housing space 16 is filled with lubricating oil. In the case of vertical installation, the initial liquid level height H is set to be substantially the same as the first buffer tank surface 14a, and most or all of the buffer tank 14 is disposed above the initial liquid level height H. The buffer tank 14 may be installed such that the first buffer tank surface 14a is below the initial liquid level height H.

  For the first shaft 32 and the second shaft 34, the initial liquid level height H is set in the first cover inner space 51 and the second cover inner space 52, respectively. For the third shaft 36 and the output shaft 30, the initial liquid level height H is set in the third bearing hole 44 and the fourth bearing hole 46, respectively.

  The initial liquid level height H may be in a predetermined allowable range. Accordingly, the first shaft 32 and the second shaft 34 may be set to the first bearing hole 40 and the second bearing hole 42, respectively. Further, the initial liquid level height H may be set in the third cover inner space 55 and the fourth cover inner space 57 for the third shaft 36 and the output shaft 30, respectively. The initial liquid level height H may be set so that at least a part of all of the first bearing 41, the second bearing 43, the third bearing 45, and the fourth bearing 47 is immersed in the lubricating oil. That is, the initial liquid level height H only needs to reach the first bearing 41, the second bearing 43, the third bearing 45, and the fourth bearing 47.

  The initial liquid level height H or the initial amount of lubricating oil corresponding thereto is set in advance as the specification of the gear device 10. The gear device 10 may include an oil gauge 48, and the initial liquid level height H may be displayed on the oil gauge 48. Alternatively, the initial liquid level height H may be described in related materials such as an instruction manual of the gear device 10. Further, the liquid level may be confirmed by an oil inspection rod. The user of the gear device 10 may be recommended by the manufacturer of the gear device 10 to start using the gear device 10 after lubricating the casing 12 to the initial liquid level height H.

  The buffer tank 14 includes air venting means 60. The air vent means 60 may be a screw or bolt with a through hole, an air breather, or other air vent mechanism. The air venting means 60 is provided in the buffer tank 14 so as to be disposed above the initial liquid level height H in the case of vertical installation. The air venting means 60 is provided on the second buffer tank surface 14b, for example.

  As described above, the air venting means 60 is provided on the second buffer tank surface 14b side, whereas the circulation pipe 18 is provided on the first buffer tank surface 14a side. One end of the recovery pipe 18a is connected to the buffer tank 14 at the first buffer tank surface 14a. The other end of the recovery pipe 18a is connected to the casing 12 at an intermediate position between the first casing surface 12a and the second casing surface 12b (for example, the same height as the axis of the input shaft 28). The return pipe 18b has one end connected to the buffer tank 14 at a position higher than the recovery pipe 18a, and the other end connected to the second casing surface 12b. Thus, the gear housing space 16 is communicated with the internal space of the buffer tank 14 through the recovery pipe 18a and the return pipe 18b.

  On the other hand, the first cover inner space 51 communicates with the second cover inner space 52 through the communication passage 53, and the second cover inner space 52 communicates with the third cover inner space 55 through the first communication pipe 20. The third cover inner space 55 is communicated with the fourth cover inner space 57 through the second communication pipe 22. Further, the fourth cover inner space 57 communicates with the inner space of the buffer tank 14 through the third communication pipe 24.

  For this purpose, the first communication pipe 20 connects the first bearing hole cover 50 to the third bearing hole cover 54, and the second communication pipe 22 connects the third bearing hole cover 54 to the fourth bearing hole cover 56. Further, the third communication pipe 24 connects the fourth bearing hole cover 56 to the buffer tank 14. In this way, the covers adjacent to each other are connected by the communication pipe. Adjacent covers are close to each other. Therefore, the length of the communication pipe can be shortened as compared with the case where the buffer tank 14 is individually connected to each cover.

  As shown in FIG. 4, the first bearing hole cover 50 is provided with a joint portion 58, and the first bearing hole cover 50 (first cover inner space 51) is connected to the first communication pipe 20 via the joint portion 58. Connected. Similarly, the third bearing hole cover 54 and the fourth bearing hole cover 56 are also provided with joint portions 58. The joint portion 58 is, for example, an L-shaped bite joint, but is not limited thereto. For example, it is also possible to provide a T-shaped joint on the bearing hole cover and connect two communication pipes to the cover.

  Thus, the first cover inner space 51 is connected to the buffer tank 14 via the second cover inner space 52, the third cover inner space 55, and the fourth cover inner space 57. Accordingly, excess air can be released from the first cover inner space 51 to the buffer tank 14. The same applies to other cover inner spaces.

  As shown in FIGS. 2 and 3, the first communication pipe 20, the second communication pipe 22, and the third communication pipe 24 are arranged above the initial liquid level height H in the case of being placed vertically. In this way, air can escape from the space in the cover to the buffer tank 14 through the communication pipe. In that sense, the communication pipe can also be called an air vent pipe.

  The third communication pipe 24 is connected to the buffer tank 14 between the air vent 60 and the circulation pipe 18 (for example, the return pipe 18b). In this way, the third communication pipe 24 can be connected to the buffer tank 14 above the circulation pipe 18 in the case of being placed vertically.

  The circulation pipe 18 is a metal pipe. The first communication pipe 20, the second communication pipe 22, and the third communication pipe 24 are metal pipes, and may be, for example, copper pipes from the viewpoint of workability. These pipes may be resin pipes such as rubber hoses.

  The first communication pipe 20, the second communication pipe 22, and the third communication pipe 24 may be pipes thinner than the circulation pipe 18. The circulation pipe 18 is desired to have a pipe diameter that guarantees a constant circulation flow rate, whereas the main role of the communication pipe is to vent air from the space in the cover to the buffer tank 14, so that a large flow rate is not required. It is.

  By the way, during operation of the gear device 10, the lubricating oil is heated and thermally expanded by rotation of the gear, frictional heat, and the like. In addition, air is entrained and stirred in the lubricating oil by the rotation of the gear. That is, the lubricating oil level during operation is higher than the initial liquid level height H. Therefore, the lubricating oil overflows from the gear housing space 16 to the buffer tank 14 through the recovery pipe 18 a and is stored in the buffer tank 14. For example, when the operation of the gear device 10 is stopped, the stored lubricating oil is returned from the buffer tank 14 to the gear housing space 16 through the return pipe 18b. In FIG. 2, the flow of the lubricating oil in each of the recovery pipe 18a and the return pipe 18b is illustrated by arrows.

  Suppose that the bearing hole cover is not provided with a communication pipe. In the case of the vertical installation, air can accumulate in a cover positioned relatively upward in the gear device 10. There is no air escape. Therefore, the lubricating oil to be supplied to the bearing from the lower gear housing space 16 is obstructed by the air and is not sufficiently supplied to the bearing.

  According to the present embodiment, the communication pipe is connected to the bearing hole cover, and the space in the cover is communicated with the buffer tank 14. Therefore, an escape space for air from the space in the cover is secured in the buffer tank 14. Finally, air can be discharged to the outside through the air venting means 60 of the buffer tank 14. Therefore, the air in the cover inner space does not hinder the supply of lubricating oil from the gear housing space 16 to the bearing. Thus, it is possible to provide the gear device 10 that enables appropriate lubrication of the bearing.

  In the above, this invention was demonstrated based on the Example. It will be understood by those skilled in the art that the present invention is not limited to the above-described embodiment, and various design changes are possible, various modifications are possible, and such modifications are within the scope of the present invention. By the way.

  FIG. 5 shows the first bearing hole cover 50 and the communication path 53 according to an embodiment. As shown in the drawing, two bent communication passages 53 are formed in the first bearing hole cover 50 so as to communicate with the first cover inner space 51 and the second cover inner space 52, respectively.

  In the embodiment described with reference to FIGS. 1 to 4, the buffer tank 14 and the plurality of cover inner spaces are connected in series, but the buffer tank 14 and the plurality of cover inner spaces may be connected in parallel. Good. For example, each of the first cover inner space 51, the second cover inner space 52, the third cover inner space 55, and the fourth cover inner space 57 may be connected to the buffer tank 14 by an individual communication pipe.

  In an embodiment, a bearing hole cover having a through hole (for example, a fourth bearing hole cover 56 having a fourth cover through hole 56b) may be connected to the buffer tank 14 by a communication pipe.

  At least one of the plurality of bearing holes formed in the casing 12 may be a non-through bearing hole that does not penetrate the casing 12. The internal space of such a non-through bearing hole may be connected to the buffer tank 14 by a communication pipe.

  Further, at least one of the plurality of through-holes formed in the casing 12 may be a shaft hole that does not have a bearing but through which a shaft is inserted. If necessary, a cover for closing the shaft hole may be provided, and the cover may be connected to the buffer tank 14 by a communication pipe.

  The connection between the cover inner space (or the inner space of the non-penetrating bearing hole) and the buffer tank 14 is not limited to the communication pipe. In an embodiment, the cover inner space (or the inner space of the non-penetrating bearing hole) may be directly connected to the buffer tank 14 or may be connected by other connection means.

  In the embodiment, the recesses (for example, the first recess 50a and the second recess 50b of the first bearing hole cover 50) are provided in the bearing hole cover corresponding to the bearing holes, but the recesses are not provided. Also good. Various shapes of the bearing hole cover are possible. For example, the inner surface of the bearing hole cover may be a flat surface. In this case, the bearing hole cover can be a simple flat member. Alternatively, a convex portion may be provided on the inner surface of the bearing hole cover corresponding to the bearing hole. The outer surface of the bearing hole cover may have an arbitrary shape.

  Needless to say, the air vent structure according to the embodiment of the present invention is not limited to the orthogonal gear device 10 but can be applied to a gear device having parallel input / output shafts or any other type of gear device. In particular, the air vent structure according to the embodiment of the present invention is suitable for a gear device that employs a lubricant supply system that does not use a pump.

  DESCRIPTION OF SYMBOLS 10 gear apparatus, 12 casing, 12a 1st casing surface, 12b 2nd casing surface, 14 buffer tank, 14a 1st buffer tank surface, 14b 2nd buffer tank surface, 16 gear accommodation space, 18 Circulation piping, 18a Recovery pipe, 18b Return pipe, 32 1st shaft, 34 2nd shaft, 36 3rd shaft, 40 1st bearing hole, 41 1st bearing, 42 2nd bearing hole, 43 2nd bearing, 44 3rd bearing hole, 45 3rd Bearing, 50 first bearing hole cover, 51 first cover inner space, 52 second cover inner space, 53 communication path, 54 third bearing hole cover, 55 third cover inner space, 60 air venting means, H initial liquid level height Well.

Claims (7)

A first bearing;
A casing having a gear housing space and capable of enclosing a liquid lubricant , the first bearing hole penetrating the casing into the gear housing space and having the first bearing disposed therein , and closing the first bearing hole A casing provided with a first bearing hole cover,
A first cover inner space that is provided between the first bearing and the first bearing hole cover inside the first bearing hole cover, and does not store gears;
A buffer tank connected to the gear housing space and capable of receiving a liquid lubricant from the gear housing space,
The gear unit, wherein the buffer tank is connected to the first cover inner space and can receive air from the first cover inner space. The casing includes a second bearing hole penetrating the casing into the gear housing space, and the first bearing hole cover closes both the first bearing hole and the second bearing hole, and the second A second cover inner space is formed corresponding to the bearing hole,
2. The gear device according to claim 1, wherein the first bearing hole cover includes a communication passage that communicates the second cover inner space with the first cover inner space. The casing includes a third bearing hole that penetrates the casing to the gear housing space, and a third bearing hole cover that closes the third bearing hole,
3. The gear device according to claim 1, wherein the buffer tank is connected to the first cover inner space via a third cover inner space inside the third bearing hole cover. The buffer tank includes air venting means,
The gear device includes a lubricant circulation pipe that connects the gear housing space to the buffer tank, and a communication pipe that connects the inner space of the first cover to the buffer tank,
The gear device according to any one of claims 1 to 3, wherein the communication pipe is connected to the buffer tank between the air venting means and the lubricant circulation pipe. The gear device includes a lubricant circulation pipe that connects the gear housing space to the buffer tank,
The lubricant circulation pipe includes a recovery pipe for receiving the liquid lubricant overflowing from the gear housing space into the buffer tank, a return pipe for returning the liquid lubricant from the buffer tank to the gear housing space, The gear device according to any one of claims 1 to 4, further comprising: Said to extend from the gear accommodating space has a gear accommodated in the gear accommodating space to the first bearing hole, further comprising a first shaft that will be supported by the first bearing,
6. The gear device according to claim 1, wherein a part and / or an end surface of the side surface of the first shaft faces the first cover inner space. The casing includes a first casing surface that can be installed on an installation surface, and a second casing surface on the opposite side of the first casing surface across the gear housing space and having the first bearing hole,
When the first casing surface is installed on the installation surface, the second casing surface is positioned vertically above the first casing surface, and an initial liquid level height of the liquid lubricant is in the first bearing hole. The gear device according to claim 1, wherein the gear device reaches a first bearing to be arranged.

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