JP7138519B2 - drive and work machine - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving device that includes a fixed case and a rotating case that is rotatable with respect to the fixed case, and a working machine that includes the driving device.

2. Description of the Related Art Conventionally, as a working machine such as a hydraulic excavator, a working machine equipped with an endless track (crawler) for traveling on rough terrain has been used. As a driving device for driving the crawler, for example, a hydraulic driving device with a speed reducer is used. A hydraulic drive device with a reduction gear uses, for example, a hydraulic motor such as a swash plate type hydraulic motor housed in a fixed case, and a planetary gear mechanism housed in a rotating case configured to be rotatable with respect to the fixed case. and a speed reduction mechanism. A flange portion is provided on the outer surface of the rotating case, and a sprocket that engages with the crawler is connected to the rotating case via this flange portion.

In such a hydraulic drive device with a speed reducer, pressure oil introduced into the hydraulic motor rotates a shaft connected to the hydraulic motor. The rotation of the shaft is decelerated by the deceleration mechanism and transmitted to the rotating case, thereby rotating the rotating case with respect to the stationary case. As the rotating case rotates, the sprocket connected to the rotating case rotates, thereby circulating the crawler engaged with the sprocket.

Between the fixed case and the rotary case of the driving device, there is a seal portion having a gap of, for example, about 0.5 mm to 2 mm so that the fixed case and the rotary case do not come into contact with each other during rotation of the rotary case. formed. Here, if a foreign object such as earth and sand enters the driving device through the gap in the seal portion while the work machine is running, the hydraulic motor and the speed reduction mechanism housed inside the fixed case and the rotating case will suffer problems. There is fear. Therefore, it is possible to prevent foreign matter such as earth and sand from entering the driving device through the gap in the sealing portion, and to quickly discharge the foreign matter to the outside of the driving device when the foreign matter has entered the gap in the sealing portion. , is desired.

Patent Literature 1 discloses a labyrinth seal for preventing the intrusion of earth and sand in a final reduction gear of a construction machine such as a power shovel. The labyrinth seal is composed of the wall surfaces of the hub, which is the rotating part, and the housing case, which is the fixed part, facing each other. and parallel planes parallel to each other. FIGS. 3 to 6 of Patent Literature 1 also disclose that a protrusion is formed on an inclined surface or parallel surface on the rotating side or fixed side so as to protrude toward the opposing inclined surface or parallel surface. As a result, there is an advantage that as the hub, which is a rotating part, rotates, the protruding part collides with the dirt that has entered and the dirt is pushed out.

JP-A-2000-346205

Foreign matter such as sand that has entered the seal portion of the driving device rotates around the axis as the rotating portion (rotating case, hub) rotates around the axis. At this time, a centrifugal force acts on the foreign matter in a direction perpendicular to the axis. In the technique of Patent Document 1, since the protrusion is formed on the inclined surface or the parallel surface of the labyrinth seal, when the protrusion pushes out the earth and sand as the hub rotates, it acts in a direction perpendicular to the axis of the hub. Centrifugal force could not be used effectively. For this reason, it is considered that the technique of Patent Document 1 cannot sufficiently discharge foreign matter such as earth and sand that have entered the seal portion.

SUMMARY OF THE INVENTION The present invention has been made in consideration of such points, and provides a driving device and a working machine that can effectively discharge foreign matter such as earth and sand that have entered the seal portion between the fixed case and the rotating case. intended to provide

The drive device according to the invention comprises:
a fixed case having a fixed-side sealing surface;
a rotary case that is rotatable about an axis with respect to the fixed case and has a rotary-side seal surface that faces the fixed-side seal surface along the axial direction;
At least one of the fixed-side seal surface and the rotary-side seal surface has a convex portion.

In the drive device according to the invention,
The convex portion may be for discharging foreign matter.

In the drive device according to the invention,
The fixed-side seal surface and the rotary-side seal surface may be perpendicular to the axial direction.

In the drive device according to the invention,
The convex portion has a pair of side surfaces facing each other in a circumferential direction about the axis,
At least one side surface of the pair of side surfaces is inclined with respect to both the circumferential direction and the radial direction so as to approach the other side surface as the distance from the axis increases along the radial direction centered on the axis. may be

In the drive device according to the invention,
The convex portion includes a first convex portion arranged radially inward about the axis and a second convex portion arranged radially outward,
The first convex portion and the second convex portion may be displaced in a circumferential direction around the axis.

A working machine according to the present invention comprises:
A drive as described above.

According to the present invention, it is possible to provide a driving device and a working machine that can effectively discharge foreign matter such as earth and sand that have entered the seal portion between the fixed case and the rotating case.

FIG. 1 is a diagram for explaining an embodiment according to the present invention, and is a diagram showing an example of a driving device. FIG. 2 is an enlarged view of a sealing portion of the driving device. FIG. 3 is a view of the rotation-side seal surface of the driving device viewed along the axial direction. FIG. 4 is a perspective view showing a convex portion on the rotary side seal surface. FIG. 5 is a diagram showing a modification of the convex portion. FIG. 6 is a diagram showing another modified example of the convex portion. FIG. 7 is a diagram showing still another modified example of the convex portion. FIG. 8 is a diagram showing a modified example of the seal portion of the driving device.

A driving device according to an embodiment of the present invention will be described below with reference to the drawings. The drive device of the present embodiment can be used as a drive device for driving a crawler of a working machine such as a hydraulic excavator, but is not limited to this, and the drive device can be used to drive a crawler of another machine. or may be used to drive devices other than crawlers. In particular, the drive of the present invention can be utilized in environments in which foreign objects such as liquids, solids and mixtures thereof are present in its surroundings which are not desired to enter the drive. FIG. 1 is a diagram for explaining an embodiment according to the present invention, and is a diagram showing an example of a driving device. In FIG. 1, the drive device is only partially shown in cross section, and the other portions are shown externally. FIG. 2 is a view showing the sealing portion of the driving device, and is a cross-sectional view showing an enlarged portion surrounded by a dashed line denoted by reference numeral II in FIG. 1 .

The driving device 10 includes a fixed case 20 and a rotary case 30 configured to be rotatable about an axis (rotational axis) A with respect to the fixed case 20 . In this specification, the direction in which the axis A extends (horizontal direction in FIG. 1) is called the "axial direction (da)", and the direction perpendicular to the axis A is called the "radial direction (dr)". A direction of rotation about the axis A is called a "circumferential direction (dc)". In addition, in the radial direction, the side closer to the axis A is called the radial "inner side", and the side away from the axis A is called the radial "outer side".

The fixed case 20 is fixed to the frame of the work machine with bolts or the like. The fixed case 20 of this embodiment accommodates a hydraulic motor (not shown) therein. As the hydraulic motor, for example, a swash plate type hydraulic motor can be used. The rotating case 30 is supported by the stationary case 20 via bearings 16 . Rotating case 30 of the present embodiment accommodates a speed reducer (not shown) therein. As the speed reducer, for example, a speed reducer having a planetary gear mechanism can be used. A detailed description of the interior of the drive device 10 is omitted here because a drive device including a hydraulic motor and a speed reducer is well known. As an example, as the hydraulic motor and speed reducer of the drive device 10, it is possible to use a hydraulic motor and speed reducer as disclosed in Japanese Patent Application Laid-Open No. 2002-213568.

The rotary case 30 has a flange portion 35 protruding from its outer wall portion in the radial direction dr about the axis A. As shown in FIG. Especially in the example shown in FIG. 1, the flange portion 35 protrudes from the outer wall portion of the rotary case 30 so as to extend in a direction perpendicular to the axis A. As shown in FIG. The flange portion 35 is a member connected to a sprocket (not shown) for circulating the crawlers. A plurality of bolt holes 36 are provided in the flange portion 35 along the circumferential direction dc. The bolt hole 36 is a hole through which a bolt for connecting the flange portion 35 and the sprocket is inserted.

When the driving device 10 is used as a driving device for driving a crawler of a work machine, pressure oil generated by a hydraulic pump (not shown) and introduced into a hydraulic motor rotates a shaft connected to the hydraulic motor. Rotation of the shaft is transmitted to a speed reducer connected to the shaft, reduced by the speed reducer, and transmitted to the rotating case 30 . As the rotating case 30 rotates, a sprocket (not shown) connected to the flange portion 35 of the rotating case 30 rotates, thereby circulating the crawler engaged with the sprocket.

A seal portion 12 is formed between the fixed case 20 and the rotary case 30 . A gap 14 is provided in the seal portion 12 so that the fixed case 20 and the rotary case 30 do not contact each other while the rotary case 30 is rotating. The dimension of the gap 14 along the axial direction da can be, for example, 0.5 mm or more and 2 mm or less. In order to prevent foreign matter such as earth and sand outside the drive device 10 from entering the drive device 10 through the gap 14, the gap 14 has a cross section passing through the axis A, that is, a cross section shown in FIGS. It is formed in a bent shape at the end, thereby forming a so-called labyrinth seal. A floating seal 18 is provided inside the gap 14 in the radial direction dr. The floating seal 18 prevents the oil filled in the driving device 10 from flowing out of the driving device 10, and foreign matter such as earth and sand outside the driving device 10 that has passed through the gap 14 enters the driving device 10. to prevent

The stationary case 20 has stationary side seal surfaces 21 and 22 facing the rotating case 30 . Especially in the example shown in FIG. 2, the stationary case 20 has a first stationary seal surface 21 and a second stationary seal surface 22 arranged outside the first stationary seal surface 21 in the radial direction dr. , and a connection surface 23 that connects the first stationary seal surface 21 and the second stationary seal surface 22 . The fixed-side seal surfaces 21 and 22 face the rotating case 30 side in the axial direction da. The stationary seal surfaces 21 and 22 are orthogonal to the axial direction da, and the connecting surface 23 is orthogonal to the radial direction dr. In other words, the stationary seal surfaces 21 and 22 extend along the radial direction dr and the circumferential direction dc, and the connecting surface 23 extends along the axial direction da and the circumferential direction dc. The first stationary-side sealing surface 21 and the second stationary-side sealing surface 22 are arranged to be shifted in the axial direction da. In particular, in the illustrated example, the first stationary seal surface 21 is positioned shifted toward the rotary case 30 in the axial direction da with respect to the second stationary seal surface 22 . That is, the first stationary seal surface 21 protrudes in the axial direction da more than the second stationary seal surface 22 . Thereby, the connecting surface 23 faces outward in the radial direction dr.

The rotary case 30 has rotary side seal surfaces 31 and 32 facing the fixed case 20 . In particular, in the illustrated example, the rotary case 30 includes a first rotary-side seal surface 31, a second rotary-side seal surface 32 arranged outside the first rotary-side seal surface 31 in the radial direction dr, and a first rotary-side seal surface 31. and a connection surface 33 that connects the rotation-side seal surface 31 and the second rotation-side seal surface 32 . The rotary-side seal surfaces 31 and 32 face the fixed case 20 side in the axial direction da. The rotary-side seal surfaces 31 and 32 are orthogonal to the axial direction da, and the connecting surface 33 is orthogonal to the radial direction dr. In other words, the rotary-side seal surfaces 31 and 32 extend along the radial direction dr and the circumferential direction dc, and the connecting surface 33 extends along the axial direction da and the circumferential direction dc. The first rotation-side seal surface 31 and the second rotation-side seal surface 32 are arranged to be shifted in the axial direction da. In particular, in the illustrated example, the second rotary-side seal surface 32 is shifted toward the fixed case 20 in the axial direction da from the first rotary-side seal surface 31 . That is, the second rotary-side seal surface 32 protrudes further in the axial direction da than the first rotary-side seal surface 31 . Thereby, the connecting surface 23 faces inward in the radial direction dr.

The stationary-side seal surfaces 21, 22 and the rotary-side seal surfaces 31, 32 face each other along the axial direction da. Especially in the illustrated example, the first stationary side seal surface 21 and the first rotary side seal surface 31 face each other along the axial direction da, and the second stationary side seal surface 22 and the second rotary side seal surface 32 face each other. face each other along the axial direction da. Moreover, the connection surface 23 and the connection surface 33 face each other along the radial direction dr.

The fixed-side seal surfaces 21 and 22 or the rotary-side seal surfaces 31 and 32 are provided with foreign matter discharge protrusions (protrusions) 40 . FIG. 3 is a view of the rotary-side seal surfaces 31 and 32 of the driving device 10 viewed along the axial direction da, and in particular, the rotary-side seal surfaces 31 and 32 are viewed along the arrow III in FIG. It is a diagram. FIG. 4 is a perspective view showing a second convex portion 42 as an example of the foreign matter discharging convex portion 40. As shown in FIG. In addition, in FIGS. 3 and 4 , the surface of the foreign object discharge projection 40 facing the fixed case 20 is hatched.

The foreign matter discharging convex portion 40 includes a first convex portion 41 and a second convex portion 42 . The first convex portion 41 is formed to protrude from the first rotating side seal surface 31 toward the fixed case 20 in the axial direction da, and the second convex portion 42 is formed to protrude from the second rotating side seal surface 32 toward the fixed case 20 in the axial direction da. It is formed to protrude to the 20 side. A gap 14 is formed between the stationary side seal surfaces 21 and 22 and the rotary side seal surfaces 31 and 32, and both the first convex portion 41 and the second convex portion 42 are formed so as to protrude into the gap 14. It is A first convex portion 41 is formed on the first rotation side seal surface 31 located inside in the radial direction dr, and a second convex portion 42 is formed on the second rotation side seal surface 32 located outside in the radial direction dr. there is Therefore, the foreign matter discharging convex portion 40 includes a first convex portion 41 arranged inside in the radial direction dr and a second convex portion 42 arranged outside in the radial direction dr. The foreign matter discharging projection 40 is arranged such that the rotary side seal surfaces 31 and 32 and the fixed side seal surfaces 21 and 22 facing the rotary side seal surfaces 31 and 32 are spaced apart from each other so that the distance between the rotary side seal surfaces 31 and 32 and the fixed side seal surfaces 21 and 22 facing the rotary side seal surfaces 31 and 32 is narrow. It is sufficient if it is provided in Further, when the foreign matter discharging convex portion 40 is provided on the stationary side seal surfaces 21 and 22, the foreign matter discharging convex portion 40 faces the stationary side seal surfaces 21 and 22 and the fixed side seal surfaces 21 and 22. It suffices if they are provided on the stationary side seal surfaces 21 and 22 so that the distance from the rotary side seal surfaces 31 and 32 is narrow. Note that the foreign matter discharging protrusions 40 may be provided on both the fixed side seal surfaces 21 and 22 and the rotary side seal surfaces 31 and 32 .

A plurality of first projections 41 are arranged along the circumferential direction dc on the first rotation-side seal surface 31 at equal angular intervals with respect to the axis A, and on the second rotation-side seal surface 32, there are circumferential A plurality of second protrusions 42 are arranged at equal angular intervals with respect to the axis A along the direction dc. In particular, in the illustrated example, the angular interval between two adjacent first projections 41 in the circumferential direction dc with respect to the axis A and the angular interval between two adjacent second projections 42 in the circumferential direction dc with respect to the axis A are: are identical.

The first convex portion 41 has an inner side surface 41a facing inward in the radial direction dr, an outer side surface 41b facing outward in the radial direction dr, and a pair of side surfaces 41c and 41d connecting the inner side surface 41a and the outer side surface 41b. ing. Of the pair of side surfaces 41c and 41d, the first side surface 41c is positioned on one side in the circumferential direction dc, and the second side surface 41d is positioned on the other side in the circumferential direction dc. The second convex portion 42 has an inner side surface 42a facing inward in the radial direction dr, an outer side surface 42b facing outward in the radial direction dr, and a pair of side surfaces 42c and 42d connecting the inner side surface 42a and the outer side surface 42b. have. Of the pair of side surfaces 42c and 42d, the first side surface 42c is positioned on one side in the circumferential direction dc, and the second side surface 42d is positioned on the other side in the circumferential direction dc.

At least one side surface of the pair of side surfaces 41c and 41d of the first protrusion 41 is arranged in both the circumferential direction dc and the radial direction dr so as to approach the other side surface as it separates from the axis A along the radial direction dr. is sloping. At least one side surface of the pair of side surfaces 42c and 42d of the second convex portion 42 is arranged in both the circumferential direction dc and the radial direction dr so as to approach the other side surface as the distance from the axis A along the radial direction dr increases. is tilted with respect to Particularly, in the illustrated example, the first side surfaces 41c and 42c move closer to the second side surfaces 41d and 42d as they separate from the axis A along the radial direction dr, that is, toward the other side in the circumferential direction dc. , are inclined with respect to both the circumferential direction dc and the radial direction dr. It is inclined with respect to both the circumferential direction dc and the radial direction dr so as to face one side of the direction dc.

The widths of the protrusions 41 and 42 along the circumferential direction dc change so as to become narrower from the inside toward the outside in the radial direction dr. Particularly in the illustrated example, the widths of the convex portions 41 and 42 along the circumferential direction dc always change so as to become narrower from the inner side toward the outer side in the radial direction dr. In other words, the widths of the protrusions 41 and 42 along the circumferential direction dc change only so as to narrow from the inside toward the outside in the radial direction dr. In the example shown in FIGS. 3 and 4, the convex portions 41 and 42 have contours that form line symmetry with a line extending along the radial direction dr as the axis of symmetry when viewed from the axial direction da. In particular, in the illustrated example, the projections 41 and 42 have a substantially trapezoidal shape, especially a substantially trapezoidal shape, with the first side surfaces 41c and 42c as lower bases and the second side surfaces 41d and 42d as upper bases when viewed from the axial direction da. The legs have a trapezoidal profile.

When the drive device 10 is used in an environment where foreign matter such as earth and sand is present, such as when the work machine is running, the foreign matter may enter the gap 14 in the seal portion 12 of the drive device 10 . If this foreign matter enters the driving device 10 through the gap 14, there is a possibility that the hydraulic motor, the speed reduction mechanism, etc. accommodated inside the fixed case 20 and the rotary case 30 may malfunction. In the driving device 10 of the present embodiment, when the rotary case 30 rotates about the axis A with respect to the fixed case 20, the seal surfaces 31 and 32 on the rotary side protrude into the gap 14 accordingly. The foreign object discharging convex portion 40 (the first convex portion 41 and the second convex portion 42) also rotates around the axis A. As shown in FIG. At this time, the foreign matter present in the gap 14 is pushed out in the radial direction dr by the first side surfaces 41c and 42c or the second side surfaces 41d and 42d of the foreign matter discharge convex portion 40 that moves along the circumferential direction dc. , is discharged out of the gap 14 .

More specifically, when the foreign matter discharging convex portion 40 moves toward one side in the circumferential direction dc (see FIG. 3), the foreign matter present in the gap 14 moves toward one side in the circumferential direction dc. The first side surfaces 41c and 42c are pushed outward in the radial direction dr. Further, when the foreign matter discharge convex portion 40 moves toward the other side in the circumferential direction dc, the foreign matter present in the gap 14 is moved toward the other side in the circumferential direction dc by the second side surfaces 41d and 42d. , is pushed outward in the radial direction dr.

At this time, the foreign matter present in the gap 14 rotates around the axis A as the rotary case 30 (rotating side seal surfaces 31 and 32) rotates around the axis A. As shown in FIG. As a result, a centrifugal force directed outward in the radial direction dr acts on the foreign matter. Therefore, the direction in which the foreign matter is pushed out by the foreign matter discharge protrusion 40 moving along the circumferential direction dc coincides with the direction of the centrifugal force acting on the foreign matter as the rotary case 30 rotates. As a result, the foreign matter can be pushed out by the foreign matter discharging protrusion 40 while effectively utilizing the centrifugal force acting on the foreign matter. Therefore, foreign matter that has entered the gap 14 can be efficiently discharged.

Further, in the present embodiment, the foreign matter discharging convex portion 40 includes the first convex portion 41 arranged inside in the radial direction dr and the first convex portion 41 arranged outside the first convex portion 41 in the radial direction dr. 2 projecting portions 42, foreign matter that has entered the gap 14 inside the radial direction dr is first discharged to the outside of the gap 14 in the radial direction dr by the first projecting portion 41, and then discharged by the second projecting portion 41. 42 allows this foreign matter to be discharged to the outside of the gap 14 . Therefore, even if foreign matter enters deep into the gap 14 , the foreign matter can be efficiently discharged to the outside of the driving device 10 .

In the example shown in FIG. 3, the first convex portion 41 and the second convex portion 42 are displaced in the circumferential direction dc. That is, the angular position of the first projection 41 with respect to the axis A and the angular position of the second projection 42 with respect to the axis A are different. As a result, the first convex portion 41 moving in the circumferential direction dc moves the foreign matter discharged outward in the radial direction dr in the gap 14 at a specific angular position with respect to the axis A to the first convex portion 41 followed by the specific angular position. By the second protrusion 42 reaching the angular position of , it is possible to discharge to the outside of the gap 14 . Therefore, the foreign matter that has entered deep into the gap 14 can be quickly discharged to the outside of the driving device 10 .

Especially in the illustrated example, the second protrusion 42 is arranged at the center in the circumferential direction dc of the angular interval with respect to the axis A of the two first protrusions 41 adjacent in the circumferential direction dc. Also, the first protrusion 41 is arranged at the center in the circumferential direction dc of the angular interval with respect to the axis A between the two second protrusions 42 adjacent in the circumferential direction dc. In this case, regardless of whether the rotary case 30 rotates in one side or the other side in the circumferential direction dc with respect to the fixed case 20, the foreign matter can be discharged out of the drive device 10 in a well-balanced and rapid manner. can be done.

In the above description, the first side surfaces 41c, 42c and the second side surfaces 41d, 42d of the foreign matter discharging convex portion 40 are closer to the other side surface as they are separated from the axis A along the radial direction dr. , but the shape of the first side faces 41c, 42c and the second side faces 41d, 42d is not limited to this. When the rotary case 30 rotates only in one direction in the circumferential direction dc, only one of the pair of side surfaces facing in the one direction approaches the other side surface as it separates from the axis A along the radial direction dr. You may incline with respect to both the circumferential direction dc and the radial direction dr so that it may carry out.

Further, in the above description, an example in which the foreign matter discharge protrusions 40 are provided on both the first rotation side seal surface 31 and the second rotation side seal surface 32 has been described, but the present invention is not limited to this. The foreign matter discharge protrusion 40 may be provided only on the side seal surface 31 or the second rotary side seal surface 32 . Furthermore, the first fixed side seal surface 21 and the second fixed side seal surface 22 of the fixed case 20 may be provided with the foreign matter discharge convex portion 40, or the first fixed side seal surface 21 or the second fixed side seal surface 22 may be provided with the foreign matter discharging protrusion 40 only. Even in the case where the first fixed side seal surface 21 and/or the second fixed side seal surface 22 is provided with the foreign matter discharge convex portion 40, the foreign matter in the gap 14 moves in the circumferential direction dc as the rotary case 30 rotates. Since the foreign matter moves along, the foreign matter collides with the side surfaces of the foreign matter discharge convex portion 40 that are inclined with respect to both the circumferential direction dc and the radial direction dr, and is pushed out in the radial direction dr. That is, even in this case, the same effect as the example described above can be exhibited.

The driving device 10 of the present embodiment includes a fixed case 20 having fixed side seal surfaces 21 and 22, and a fixed case 20 that is rotatable about an axis A with respect to the fixed case 20, and that the fixed side seal surface 21 is rotatable along an axial direction da. , 22 and a rotary case 30 having rotary side seal surfaces 31 and 32 facing each other, and at least one of the stationary side seal surfaces 21 and 22 and the rotary side seal surfaces 31 and 32 has a convex portion 40 .

In the driving device 10 of the present embodiment, the convex portion 40 is for discharging foreign matter.

The working machine of the present embodiment includes the driving device 10 described above.

According to the driving device 10 and the working machine as described above, the convex portion 40 is rotated around the axis A as the rotary case 30 rotates, and the convex portion 40 fills the gap between the fixed case 20 and the rotary case 30 . Foreign matter such as earth and sand existing inside 14 can be pushed out in the radial direction dr and discharged out of the gap 14 . In addition, since the direction in which the foreign matter is pushed out by the convex portion 40 moving along the circumferential direction dc coincides with the direction of the centrifugal force acting on the foreign matter as the rotation case 30 rotates, the centrifugal force acting on the foreign matter is reduced. Foreign matter can be pushed out by the convex portion 40 while being effectively used. Therefore, the foreign matter that has entered the gap 14 can be efficiently discharged to the outside of the driving device 10 . As a result, it is possible to effectively prevent malfunctions of the hydraulic motor, speed reduction mechanism, etc. accommodated inside the fixed case 20 and the rotary case 30 due to foreign matter entering the driving device 10 through the gap 14. can be done.

In the driving device 10 of the present embodiment, the fixed side seal surfaces 21 and 22 and the rotary side seal surfaces 31 and 32 are perpendicular to the axial direction da.

According to such a driving device 10, the direction of the centrifugal force acting on the foreign matter in the direction perpendicular to the axis A and the direction in which the foreign matter is pushed out by the convex portion 40 moving along the circumferential direction dc can be determined more accurately. , the foreign matter that has entered the gap 14 can be more efficiently discharged to the outside of the driving device 10 .

In the driving device 10 of the present embodiment, the convex portion 40 has a pair of side surfaces (41c, 42c) and (41d, 42d) facing each other in the circumferential direction dc about the axis A, and the pair of side surfaces (41c , 42c), and (41d, 42d) along the radial direction dr centered on the axis A so as to come closer to the other side as the distance from the axis A increases. slanted for both.

According to such a drive device 10, along with the rotation of the rotary case 30, along the side surfaces 41c, 41d, 42c, and 42d that are inclined with respect to both the circumferential direction dc and the radial direction dr, the slanted surfaces are present in the gap 14. It is possible to push the foreign matter to the outside in the radial direction dr and discharge it out of the gap 14 . Therefore, it is possible to more efficiently discharge the foreign matter that has entered the gap 14 to the outside of the driving device 10 .

In the driving device 10 of the present embodiment, the convex portions 40 include a first convex portion 41 arranged inside in the radial direction dr centering on the axis A, and a second convex portion 41 arranged outside in the radial direction dr. 42 , and the first protrusion 41 and the second protrusion 42 are arranged to be displaced in the circumferential direction dc about the axis A. As shown in FIG.

According to the driving device 10 described above, the first convex portion 41 moving in the circumferential direction dc moves foreign matter discharged outward in the radial direction dr in the gap 14 at a specific angular position with respect to the axis A to the first convex portion 41 . The second convex portion 42 that reaches the specific angular position following the portion 41 enables discharge to the outside of the gap 14 . Therefore, the foreign matter that has entered deep into the gap 14 can be quickly discharged to the outside of the driving device 10 .

Various modifications can be made to the above-described embodiment. Modifications will be described below with appropriate reference to the drawings. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding portions in the above-described embodiment are used for the parts that can be configured in the same manner as in the above-described embodiment, Duplicate explanations are omitted.

FIGS. 5 to 7 show modifications of the projections (projections) 40 for discharging foreign matter. 5 to 7 are diagrams showing one of the first protrusions 41 in each modification viewed from the axial direction da as a representative example of the shape of the foreign matter discharge protrusion 40 in each modification. In addition, in each modification, the second convex portion 42 can also be configured to have a shape similar to the shape of the convex portion shown in FIGS.

The first convex portion 41 according to the modification shown in FIG. 5 has an inner side surface 41a facing inward in the radial direction dr and a pair of side surfaces 41c and 41d. The first side surface 41c and the second side surface 41d are connected to each other at the end opposite to the end connected to the inner side surface 41a. Also, the first side surface 41c and the second side surface 41d are formed linearly when viewed from the axial direction da. The first convex portion 41 according to this modified example has an outline of a substantially triangular shape, particularly a substantially isosceles triangular shape, with the inner side surface 41a as the base when viewed from the axial direction da.

The first convex portion 41 according to the modification shown in FIG. 6 has an outer side surface 41b facing outward in the radial direction dr and a pair of side surfaces 41c and 41d connecting the inner side surface 41a and the outer side surface 41b. . The first side surface 41 c and the second side surface 41 d each have a curvilinear shape that protrudes toward the inside of the first protrusion 41 when viewed from the axial direction da, in other words, becomes concave toward the outside of the first protrusion 41 . has the shape of

The first convex portion 41 according to the modification shown in FIG. 7 has an inner side surface 41a facing inward in the radial direction dr and a pair of side surfaces 41c and 41d. The first side surface 41c and the second side surface 41d are connected to each other at the end opposite to the end connected to the inner side surface 41a. In addition, the first side surface 41c and the second side surface 41d are each convex toward the inside of the first convex portion 41 when viewed from the axial direction da, in other words, concave toward the outside of the first convex portion 41. It has a curvilinear shape.

5 to 7 also causes the foreign matter discharging convex portion 40 (first convex portion 41) to rotate around the axis A as the rotary case 30 rotates, The foreign matter discharge protrusion 40 can push foreign matter such as earth and sand present in the gap 14 between the fixed case 20 and the rotary case 30 to the outside in the radial direction dr to discharge the foreign matter outside the gap 14 .

FIG. 8 is a diagram for explaining another modification of the driving device 10. FIG. FIG. 8 is a view corresponding to FIG. 2, and is an enlarged cross-sectional view showing the seal portion 12 and its vicinity of the drive device 10 according to the present modification.

In the example shown in FIG. 8, the second stationary-side sealing surface 22 is shifted toward the rotary case 30 in the axial direction da from the first stationary-side sealing surface 21 . That is, the second stationary seal surface 22 protrudes in the axial direction da more than the first stationary seal surface 21 . Thereby, the connecting surface 23 faces inward in the radial direction dr.

In addition, the first rotation-side seal surface 31 is positioned to be shifted toward the fixed case 20 in the axial direction da from the second rotation-side seal surface 32 . That is, the first rotation-side seal surface 31 protrudes further in the axial direction da than the second rotation-side seal surface 32 . Thereby, the connecting surface 23 faces outward in the radial direction dr.

With such a driving device 10 as well, the foreign matter discharging convex portion 40 is rotated around the axis A as the rotary case 30 rotates, and the foreign matter discharging convex portion 40 moves between the fixed case 20 and the rotary case 30 . Foreign matter such as earth and sand present in the gap 14 can be pushed out in the radial direction dr and discharged out of the gap 14 .

As another modification, in the above-described embodiment, the first protrusion 41 and the second protrusion 42 have similar shapes when viewed from the axial direction da. , the first convex portion 41 and the second convex portion 42 may have different shapes when viewed from the axial direction da.

Although some modifications of the above-described embodiment have been described above, it is of course possible to appropriately combine and apply a plurality of modifications.

10 Driving device 12 Seal part 14 Gap 20 Fixed case 21 First fixed side seal surface 22 Second fixed side seal surface 23 Connection surface 30 Rotation case 31 First rotation side seal surface 32 Second rotation side seal surface 33 Connection surface 40 Foreign matter Ejection protrusion 41 First protrusion 41a Inner side 41b Outer side 41c First side 41d Second side 42 Second protrusion 42a Inner side 42b Outer side 42c First side 42d Second side A Axis

Claims (6)

a fixed case having a fixed-side sealing surface;
a rotary case that is rotatable about an axis with respect to the fixed case and has a rotary-side seal surface that faces the fixed-side seal surface along the axial direction;
at least one of the fixed-side seal surface and the rotary-side seal surface has a convex portion;
The convex portion includes a first convex portion arranged radially inward about the axis and a second convex portion arranged radially outward,
The driving device , wherein the first protrusion and the second protrusion are arranged to be shifted in the axial direction . 2. The driving device according to claim 1, wherein said convex portion is for discharging foreign matter. 3. The driving device according to claim 1, wherein said fixed side seal surface and said rotary side seal surface are orthogonal to said axial direction. The convex portion has a pair of side surfaces facing each other in a circumferential direction about the axis,
At least one side surface of the pair of side surfaces is inclined with respect to both the circumferential direction and the radial direction so as to approach the other side surface as the distance from the axis increases along the radial direction centered on the axis. The driving device according to any one of claims 1 to 3, wherein The driving device according to any one of claims 1 to 4, wherein said first protrusion and said second protrusion are arranged to be displaced in a circumferential direction about said axis. A working machine comprising the driving device according to any one of claims 1 to 5.

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