JP5374395B2 - Oil seal - Google Patents

Description

  The present invention relates to an oil seal.

  Patent Document 1 discloses an oil seal as shown in FIG.

  The oil seal 1 includes a main seal body 3 having a main lip 2 and an auxiliary seal body 5 having an auxiliary lip 4 disposed on the inner space 6 side of the machine device relative to the main lip 2. The internal space 6 and the external space 7 are partitioned. As a result, the auxiliary seal body 5 prevents foreign matter (iron powder or the like) from entering the main seal body 3 side by the auxiliary lip 4, and the main seal body 3 is prevented from entering the external space 7 of the oil seal 1 by the main lip 2. The oil sealed in the internal space 6 of the machine is prevented from leaking to the side.

JP 2000-110946 (FIG. 1)

  However, when the pressure inside the mechanical device rises due to reasons such as an increase in the temperature inside the mechanical device, the pressure is applied to one surface in the axial direction of the auxiliary seal body arranged on the internal space side of the mechanical device. However, there is a problem that the entire oil seal may be displaced to the outside space side of the mechanical device. As a configuration for preventing the displacement, a configuration in which positioning means such as a retaining ring is added can be considered. However, a separate member is required, and the number of assembling steps is increased.

  In order to solve the above-described problems, an object of the present invention is to provide a function of preventing the displacement of the oil seal itself and effectively prevent the displacement of the oil seal as a single product.

The present invention provides a main seal body having a main lip for preventing leakage of lubricant sealed in an internal space of a mechanical device, and an auxiliary seal body having an auxiliary lip disposed on the internal space side of the main lip. An oil seal that partitions an internal space and an external space of the mechanical device, the main seal body including the main lip, and the auxiliary seal body including the auxiliary lip. The auxiliary seal body has a wall surface on the inner space side in the axial direction , and includes pressure dispersion means for dispersing the pressure generated in the inner space to parts other than the wall surface, and the pressure dispersion means Comprises a through passage that disperses the pressure generated in the internal space in a seal inner space sandwiched between the main seal body and the auxiliary seal body, and the through passage is directed from the inner space side toward the seal inner space. And The auxiliary seal body is formed by a through hole formed in an axial direction, and the through hole is opposed to the radial outer peripheral surface of the auxiliary seal body and the radial outer peripheral surface of the auxiliary seal body. The said subject was solved by setting it as the structure formed between the internal peripheral surfaces of the body .

  When pressure is generated in the internal space of the mechanical device due to a temperature rise or the like, the generated pressure is conventionally applied only to the wall surface on the internal space side of the mechanical device in the axial direction of the auxiliary seal body, and the oil seal is attached to the outside of the mechanical device. It was acting in the direction to escape to the space side. In the present invention, the pressure generated in the internal space is dispersed and applied to other than the wall surface of the auxiliary seal body. Thereby, for example, it is possible to generate a pressure component in the radial direction that increases the mounting force of the oil seal in the radial direction of the mechanical device and tries to keep the oil seal at a predetermined axial position. Due to this pressure dispersion action, the oil seal can be prevented from being displaced by itself.

  According to the present invention, the oil seal itself has a function of preventing displacement, and the displacement of the oil seal can be effectively prevented by a single product.

1 is a schematic cross-sectional view of a speed reducer to which an oil seal according to an example of an embodiment of the present invention is applied. Enlarged view of part II in Fig. 1 Side view as seen from arrow III in FIG. Schematic sectional view when inserting the oil seal Front sectional view of an oil seal according to an example of another embodiment of the present invention Side view as seen from arrow VI in FIG. Front sectional view of an oil seal according to an example of still another embodiment of the present invention. Schematic sectional view of a conventional oil seal

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

  FIG. 1 is a schematic cross-sectional view of a reduction gear device 100 to which oil seals 130 and 132 according to an example of an embodiment of the present invention are applied.

  First, the schematic configuration of the reduction gear 100 will be described.

  The reduction gear 100 includes a motor 102 and a reduction gear (mechanical device) 104.

  The motor shaft 106 of the motor 102 also serves as the input shaft of the speed reducer 104, and a first gear (hypoid pinion) 108 is formed at the tip thereof. The first gear 108 meshes with a second gear (hypoid gear) 112 connected to the intermediate shaft 110 of the speed reducer 104 by a key 111. A third gear 114 is integrally formed on the other side in the axial direction of the intermediate shaft 110 (the side opposite to the side where the second gear 112 is connected). The third gear 114 meshes with the fourth gear 122 fixed to the output shaft (hollow shaft) 120 of the speed reducer 104 by the key 127. The output shaft 120 is rotatably supported by bearings 124 and 126. The bearing 124 is incorporated between the output shaft 120 and the first casing 121, and the bearing 126 is incorporated between the output shaft 120 and the second casing 123.

  Lubricant (grease) 129 is enclosed in the internal space 160 of the speed reducer 104 in order to rotate the first to fourth gears 108, 112, 114, 122 more smoothly. In order to prevent leakage of the lubricant 129, oil seals 130 and 132 are provided on the outer space 162 side (in the axial direction) of the bearings 124 and 126, respectively.

  Here, the configuration of the oil seals 130 and 132 will be described.

  Since the oil seals 130 and 132 are the same in structure and function, only the oil seal 130 will be representatively described below.

  2 is an enlarged view of the periphery of the oil seal 130 (enlarged view obtained by rotating the portion II of FIG. 1 to the right by 90 degrees), and FIG. 3 is a side view seen from the direction of arrow III in FIG.

  The oil seal 130 is mainly composed of a main seal body 134 and an auxiliary seal body 136. The oil seal 130 has a seal inner space 138 sandwiched between the main seal body 134 and the auxiliary seal body 136 and partitions the internal space 160 and the external space 162 of the speed reducer 104.

  The main seal body 134 includes a first main lip 134A that prevents leakage of the lubricant 129 enclosed in the internal space 160 of the speed reducer 104, and a second main lip 134B that prevents dust from entering from the atmosphere side. ing.

  The auxiliary seal body 136 is located closer to the internal space 160 of the speed reducer 104 than the main seal body 134, and assists in preventing foreign matter (iron powder or the like) from entering the main seal body 134 from the internal space 160 side. It has a lip 136A.

  The oil seal 130 partitions the internal space 160 and the external space 162 of the speed reducer 104 to form a sealed space. For example, when the speed reducer 100 is operated for a long time, the temperature of the internal space 160 may increase. . As a result, a pressure P1 is generated in the internal space 160 of the speed reducer 104 and is basically applied to the wall surface 136B on the internal space 160 side in the axial direction of the auxiliary seal body 136.

  The pressure dispersing means 140 disperses the pressure P1 in the internal space 160 to parts other than the wall surface 136B. The pressure dispersing means 140 in the present embodiment includes a through passage 142 for dispersing the pressure P1 in the seal inner space 138. The through passage 142 is configured by a through hole 143 in which an auxiliary seal body 136 is formed to penetrate in the axial direction from the inner space 160 side of the speed reducer 104 toward the seal inner space 138.

  The pressure dispersing means 140 disperses the pressure P1 in the seal inner space 138 through the through hole 143. As a result, the pressure dispersing means 140 causes the pressure components P2 and P3 in the radial direction to expand the seal inner space 138 of the oil seal 130 in the radial direction (the pressure components P2 and P3 are both pressure components having the same magnitude as the pressure P1). ).

  Since the through-hole 143 is formed at a position radially away from the auxiliary lip 136A that is in contact with the output shaft 120, foreign matter mainly traveling on the surface of the output shaft 120 passes through the through-hole 143. Thus, it is difficult for the main seal body 134 to enter.

  Next, the operation of the oil seal 130 will be described.

  The pressure dispersion means 140 applies the pressure P1 generated in the internal space 160 of the speed reducer 104 to other than the wall surface 136B of the auxiliary seal body 136 through the through hole 143, and applies the pressure P1 to the seal internal space 138 (specifically, Is distributed in all directions of the seal inner space 138.

  Among the components in which the pressure P1 is dispersed, the pressure components P2 and P3 in the radial direction cause the inner space 138 of the oil seal 130 to expand in the radial direction to increase the mounting force in the radial direction, and the oil seal 130 is retained. Act on. The action is obtained by dispersing the pressure P1 by the pressure dispersing means 140, and the oil seal 130 is displaced toward the external space 162 side of the speed reducer 104 (without particularly installing a retaining ring or the like). ) Prevents.

  As described above, since the displacement of the oil seals 130 and 132 can be effectively prevented, the axial direction of the output shaft 120 and the first and second casings 121 and 123 is considered in consideration of the displacement of the oil seals 130 and 132. Since it is not necessary to increase the length, the speed reducer 104 can design the length of the output shaft 120 in the axial direction in a compact manner.

  Further, the pressure P1 does not concentrate only on the wall surface 136B of the auxiliary seal body 136, and the auxiliary lip 136A can receive the same pressure P1 from the back side of the wall surface 136B, so that the original tension force can be stably maintained. can do. For this reason, the life of the oil seal 130 (particularly, the auxiliary seal body 136) can be extended, and the reduction gear 100 can achieve continuous operation over a long period of time.

  Also, as shown in FIGS. 4A and 4B, when the oil seal 130 is inserted (assembled) into the speed reducer 104, the through-hole 143 has a space 160A between the oil seal 130 and the bearing 124. Then, the seal inner space 138 is conducted, and the compression pressure generated during assembly is received in a wider space. As a result, the compression pressure applied to the wall surface 136B of the auxiliary seal body 136 can be reduced. That is, the wall surface 136B of the auxiliary seal body 136 does not receive the compressive pressure intensively, so that the workability when the oil seal 130 is assembled can be further improved.

  Next, an oil seal 230 according to an example of another embodiment will be described.

  FIG. 5 is a front sectional view of an oil seal 230 according to an example of another embodiment of the present invention, and FIG. 6 is a side view seen from the direction of arrow VI in FIG.

  In the present embodiment, the pressure dispersing means 240 includes the radially outer wall surface 236C of the auxiliary seal body 236 and the inner wall surface of the main seal body 234 facing the radially outer wall surface (outer peripheral surface) 236C of the auxiliary seal body 236. (Inner peripheral surface) It is comprised by the through-passage 243 formed between 234C.

  Even if the pressure in the internal space 260 of the speed reducer 204 gradually rises to a pressure P4 (so that the oil seal 230 is moved to the external space 262 side), the pressure dispersing means 240 does not pass through the through passage 243. Thus, the pressure P4 in the inner space 260 is dispersed in the seal inner space 238. Thereby, pressure components P5 and P6 in the radial direction (both pressure components P5 and P6 are pressure components having the same magnitude as the pressure P4) can be generated.

  Since the through passage 243 is disposed further radially outside the auxiliary seal body 236 than the previous through hole (143), the foreign matter that travels on the surface of the output shaft 220 passes through the through passage 243. It is harder to enter. For this reason, the through passage 243 has an opening area larger than that of the through hole (143) of the above embodiment. Since the opening area of the through passage 243 is large, the through passage 243 can more easily disperse the pressure P4 to the seal inner space 238 than in the above embodiment. As a result, the pressure dispersing means 240 can further promote the action of dispersing the pressure P4, and can easily generate the pressure components P5 and P6 in the radial direction.

  Since the other configuration is basically the same as the structure of the oil seal 130 shown in FIG. 2, the same two-digit numbers are assigned to the portions corresponding to the oil seal 130 (functionally similar portions). The duplicate explanation is omitted.

  Also in the embodiments described below, the same functional symbols as those of the oil seal 130 shown in FIG.

  Next, an oil seal 330 according to another example of the embodiment will be described.

  FIG. 7 is a front sectional view of an oil seal 330 according to an example of still another embodiment of the present invention.

  In the present embodiment, the pressure dispersion unit 340 includes a protrusion 350. The protrusion 350 extends from the main seal body 336 toward the internal space 360 side of the speed reducer 304.

  The protrusion 350 has a pressure receiving surface 350A perpendicular to the wall surface 336B of the auxiliary seal body 336. Even if the pressure inside the speed reduction device 300 gradually increases and reaches the pressure P7 (which moves the oil seal 330 to the external space 362 side), the pressure receiving surface 350A is radially outward of the pressure P7 in the internal space 360. It is possible to receive the pressure component P8 toward the pressure (the pressure component P8 is a pressure component having the same magnitude as the pressure P7).

  Further, since the protruding portion 350 is provided only on the first casing 321 side, the pressure receiving surface 350A of the protruding portion 350 receives only the pressure component P8 directed radially outward (out of the radial pressure components). it can. For this reason, it is possible to increase only the mounting force of the oil seal 330 on the first casing 321 without increasing the force (sliding resistance) of the oil seal 330 against the output shaft 320, and the oil seal 330 can be displaced. It can be effectively prevented.

  In addition, in this embodiment, although the projection part is extended from the main seal body, you may make it extend from either a main seal body or an auxiliary | assistant seal body, or both.

  Further, the pressure dispersing means may be only the protrusion or only the introduction path, and may include a protrusion and a penetration path. The through path may be a through hole in which the auxiliary seal body is formed in the axial direction from the inner space side toward the seal inner space, or the radial direction outer circumferential surface of the auxiliary seal body is opposed to the outer circumferential surface. A through passage formed between the inner peripheral surface of the main seal body may be used. You may form both a through-hole and a through-passage. In addition, there is no restriction | limiting in particular about the magnitude | size of an introduction path.

DESCRIPTION OF SYMBOLS 100 ... Reduction gear 104 ... Reduction gear (mechanical device)
129 ... Lubricant 130, 132 ... Oil seal 134 ... Main seal body 134A, 134B ... First and second main lips (main lips)
136 ... Auxiliary seal body 136A ... Auxiliary lip 140 ... Pressure dispersion means 160 ... Internal space 162 ... External space P1 ... Pressure

Claims (2)

A main seal body having a main lip for preventing leakage of lubricant encapsulated in the internal space of the mechanical device, and an auxiliary seal body having an auxiliary lip disposed on the internal space side of the main lip. In the oil seal that partitions the internal space and the external space of the mechanical device,
With the main lip on the inner peripheral side of the main seal body, and with the auxiliary lip on the inner peripheral side of the auxiliary seal body,
The auxiliary seal body has a wall surface on the inner space side in the axial direction,
A pressure dispersion means for dispersing the pressure generated in the internal space to a portion other than the wall surface ;
The pressure dispersing means includes a through passage that disperses the pressure generated in the internal space in a seal inner space sandwiched between the main seal body and the auxiliary seal body;
The through passage is constituted by a through hole formed by penetrating the auxiliary seal body in the axial direction from the inner space side toward the seal inner space,
The through hole is formed between a radially outer peripheral surface of the auxiliary seal body and an inner peripheral surface of the main seal body facing the radial outer peripheral surface of the auxiliary seal body. Oil seal. Oite to claim 1,
The pressure dispersing means includes a protrusion extending from the main seal body or the auxiliary seal body toward the internal space, and the pressure generated in the internal space is caused by the protrusion in addition to the wall surface. Is also distributed ,
The protrusions oil seal, characterized in that than the wall that protrude into the inner space side.

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