Seal structures and rotating machinery

Abstract

This invention provides a technology to further avoid interference between the main sealing member and the inner sealing member. [Solution] A seal structure 10 comprising an outer member 14 and an inner member 16 that are rotatable relative to each other, and a seal unit 18 disposed between the outer member 14 and the inner member 16 for sealing a sealing space 20 provided on one side in the axial direction, wherein the seal unit 18 comprises a main seal member 24 having a main lip portion 30 that contacts a main seal surface 40 provided on the inner member 16 and attached to the outer member 14, and an inner seal member 26 which is provided separately from the inner seal member 24 and has at least a portion of it disposed on one side in the axial direction and attached to the inner member 16, and a positioning portion 54 provided separately from the inner seal member 26 for positioning the main seal member 24 in the axial direction with respect to the outer member 14.

Description

Technical Field

[0001] The present disclosure relates to a seal structure used in a rotating machine.

Background Art

[0002] Patent Document 1 discloses a seal structure used in a rotating machine. This seal structure includes an outer member and an inner member that are relatively rotatable with respect to each other, and a seal unit that is disposed between the outer member and the inner member and seals a sealing space provided on one axial side. The seal unit of Patent Document 1 includes a main seal member attached to the outer member, and an inner seal member that is at least partially disposed on one axial side of the main seal member and is attached to the inner member.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the seal unit of Patent Document 1, axial movement of the main seal member with respect to the outer member is allowed. Therefore, if the main seal member is unintentionally pushed into the sealing space side axially from the design target position, there is a risk that the main seal member will interfere with the inner seal member. If these interfere, it may cause problems, and thus improvement is desired.

[0005] One object of the present disclosure is to provide a technique for further avoiding interference of the main seal member with the inner seal member.

Means for Solving the Problems

[0006] One aspect of the present disclosure is a seal structure. The seal structure comprises an outer member and an inner member that are rotatable relative to each other, and a seal unit disposed between the outer member and the inner member for sealing a sealing space provided on one axial side, wherein the seal unit comprises a main seal member having a main lip portion that contacts a main seal surface provided on the inner member and is attached to the outer member, and an inner seal member having at least a portion disposed on one axial side with respect to the main seal member and is attached to the inner member, and further comprises a positioning portion provided separately from the inner seal member for axially positioning the main seal member with respect to the outer member.

[0007] Another aspect of this disclosure is a rotating machine, which employs the sealing structure of the aforementioned aspect. [Effects of the Invention]

[0008] According to this disclosure, interference between the main sealing member and the inner sealing member can be more easily avoided. [Brief explanation of the drawing]

[0009] [Figure 1] A side cross-sectional view of the seal structure of the first embodiment is shown. [Figure 2] A diagram illustrating the effect of overshooting is shown. [Figure 3] A side cross-sectional view of the seal structure of the second embodiment is shown. [Figure 4] A side cross-sectional view of the rotating machine according to the third embodiment is shown. [Figure 5] A side cross-sectional view of the rotating machine according to the fourth embodiment is shown. [Modes for carrying out the invention]

[0010] Embodiments for implementing the seal structure and rotating machinery of this disclosure are described below. The same or equivalent elements are denoted by the same reference numerals, and redundant descriptions are omitted. For the sake of clarity, components are omitted, enlarged, or reduced in each drawing. The drawings should be viewed in accordance with the orientation of the reference numerals.

[0011] (First Embodiment) Refer to Figure 1. The seal structure 10 is used in a rotating machine 12. Details of the rotating machine 12 will be described later. The seal structure 10 comprises an outer member 14 and an inner member 16 that can rotate relative to each other when the rotating machine 12 is in operation, and a seal unit 18 disposed between the outer member 14 and the inner member 16. In this specification, when describing the positional relationship of each component of the seal structure 10, the axial direction, radial direction, and circumferential direction are used. The axial direction refers to the direction along the rotation centerline when the outer member 14 and the inner member 16 rotate relative to each other, and the radial direction and circumferential direction refer to the radial direction and circumferential direction with respect to that rotation centerline.

[0012] The inner member 16 is positioned radially inward relative to the outer member 14. In this embodiment, the inner member 16 is rotatable.

[0013] The seal unit 18 is used to seal a sealing space 20 located on one axial side of the seal unit 18 (right side in Figure 1). The seal unit 18 isolates the sealing space 20 from the outer space 22 located on the other axial side of the seal unit 18 (left side in Figure 1). The sealing space 20 is filled with a lubricant for lubricating lubricated elements (not shown) used in the rotating machine 12. The lubricant is, for example, lubricating oil or grease. Hereinafter, the axial side of the seal unit 18 will simply be referred to as the sealing space side S1, and the side opposite the sealing space 20 in the axial direction will be referred to as the anti-sealing space side S2.

[0014] The seal unit 18 includes a main seal member 24 attached to the outer member 14, and an inner seal member 26 which is positioned at least partially on the sealing space side S1 relative to the main seal member 24 and attached to the inner member 16. In this embodiment, each of the main seal member 24 and the inner seal member 26 is made of an elastic material such as rubber. In addition, each seal member 24 and 26 may be made of a combination of a metal ring and an elastic material.

[0015] The main sealing member 24 prevents lubricant from leaking from the sealed space side S1 to the non-sealed space side S2 by sealing the gap between the outer member 14 and the inner member 16. The main sealing member 24 comprises a first main body portion 28 attached to the outer member 14 and a main lip portion 30 provided on the first main body portion 28. In addition, the main sealing member 24 may optionally include an auxiliary lip portion 32 protruding from the main lip portion 30 and a spring member 34 such as a garter spring that presses the main lip portion 30 toward the inner member 16.

[0016] The first main body portion 28 includes a first mounting portion 36 attached to the inner circumference of the outer member 14 by interference fit or the like, and a first radially extending portion 38 extending radially from the first mounting portion 36. The first mounting portion 36 extends in the axial direction. The first radially extending portion 38 extends from the axial end of the first mounting portion 36 on the non-sealing space side S2.

[0017] The main lip portion 30 extends from the radially inner end portion of the first main body portion 28 toward the sealing space side S1. The main lip portion 30 contacts the main seal surface 40 provided on the inner member 16. The main lip portion 30 contacts at a lip end portion 30a that protrudes toward the main seal surface 40 side in the main lip portion 30. Thereby, the main lip portion 30 prevents leakage of the lubricant from the sealing space side S1 to the anti-sealing space side S2 via between the main lip portion 30 and the main seal surface 40. The main seal surface 40 may be constituted by a separate member attached to the inner member 16, or may be constituted by a part of the inner member 16, as long as the condition of being provided on the inner member 16 is satisfied. The main seal surface 40 of the present embodiment is constituted by the second attachment portion 50 (described later) of the inner seal member 26, as in the former case. Specifically, the main seal surface 40 of the present embodiment is constituted by the outer peripheral surface of the second attachment portion 50.

[0018] The auxiliary lip portion 32 is provided on the anti-sealing space side S2 rather than the contact location of the main lip portion 30 with respect to the main seal surface 40, and contacts the main seal surface 40. The auxiliary lip portion 32 blocks dust that tries to flow from the outer space 22 toward the main lip portion 30 side, thereby preventing dust from entering between the main lip portion 30 and the main seal surface 40.

[0019] The inner seal member 26 blocks foreign matter that tries to flow together with the lubricant from the sealing space side S1 toward the main seal member 24 side, thereby preventing foreign matter from entering between the main lip portion 30 and the main seal surface 40. This foreign matter refers to, for example, wear powder generated by contact of a plurality of members constituting the lubricated element. This plurality of members refers to, for example, a gear pair described later. The inner seal member 26 is attached to the inner member 16 and thus can rotate together with the inner member 16. In the present embodiment, with respect to the main seal member 24, a part of the inner seal member 26, specifically, a portion including a second radially extending portion 48 described later is disposed on the sealing space side S1. In addition to this, the entire inner seal member 26 may be disposed on the sealing space side S1 with respect to the main seal member 24.

[0020] A gap space 42 is formed between the inner seal member 26 and the main seal member 24. The gap space 42 is formed at a position sandwiched between at least the main seal member 24 and the inner seal member 26. There is no other seal member partitioning the gap space 42 between the inner seal member 26 and the main seal member 24. The first radially extending portion 38 of the main seal member 24 and the second radially extending portion 48 (described later) of the inner seal member 26 form a common gap space 42.

[0021] The inner seal member 26 includes a second main body portion 44 attached to the inner member 16, and an inner lip portion 46 provided on the second main body portion 44. The second main body portion 44 includes a second radially extending portion 48 extending in the radial direction, and a second attachment portion 50 provided at the radially inner end portion of the second radially extending portion 48. The second attachment portion 50 is attached to the outer peripheral portion of the inner member 16 by an interference fit or the like. The second attachment portion 50 of the present embodiment extends toward the non-sealing space side S2 with respect to the second radially extending portion 48.

[0022] The inner lip portion 46 is provided at a tip side portion 48g on the radially outer side of the second radially extending portion 48. The inner lip portion 46 of the present embodiment is constituted by at least a part of the tip side portion 48g of the second radially extending portion 48. The inner lip portion 46 is constituted by the elastic material described above. The inner lip portion 46 contacts an inner seal surface 52 provided on the outer member 14. Thereby, the gap space 42 and the sealing space 20 are isolated by the inner seal member 26. The inner seal surface 52 may be constituted by a part of the outer member 14 or by a separate member attached to the outer member 14, as long as it satisfies the condition of being provided on the outer member 14. An example in which the inner seal surface 52 of the present embodiment is constituted by the inner peripheral surface itself of the outer member 14 as described above will be described. In addition to this, the inner seal surface 52 may be constituted by a separate member attached to the outer member 14.

[0023] In this embodiment, the seal structure 10 is provided separately from the inner seal member 26 and includes a positioning portion 54 that positions the main seal member 24 axially relative to the outer member 14. The positioning portion 54 contacts the main seal member 24 from the sealing space side S1, thereby restricting the axial movement of the main seal member 24 toward the sealing space side S1. The positioning portion 54 in this embodiment is composed of a stepped portion 56 provided on the inner circumference of the outer member 14. The stepped portion 56 is provided between a small inner diameter portion 14a and a large inner diameter portion 14b provided on the inner circumference of the outer member 14. The stepped portion 56 in this embodiment is composed of a flat surface extending radially.

[0024] The small inner diameter portion 14a is provided on the sealing space side S1 relative to the stepped portion 56. The small inner diameter portion 14a is provided with an inner sealing surface 52 that contacts the inner lip portion 46 of the inner sealing member 26. In this embodiment, the corner formed by the stepped portion 56 and the small inner diameter portion 14a is provided with a slanted portion 14c that extends radially inward toward the sealing space side S1. The large inner diameter portion 14b is provided on the opposite side S2 relative to the stepped portion 56 and has a larger inner diameter than the small inner diameter portion 14a. The first mounting portion 36 of the main sealing member 24 is attached to the large inner diameter portion 14b. Due to the presence of the small inner diameter portion 14a and the large inner diameter portion 14b, the outer diameter of the main sealing member 24 is larger than the outer diameter of the inner sealing member 26. This relationship of outer diameters is satisfied when the sealing unit 18 is positioned between the outer member 14 and the inner member 16.

[0025] The effects of the seal structure 10 described above will now be explained. Let's consider the case where axial movement of the main seal member 24 relative to the outer member 14 is permitted. In this case, the main seal member 24 may be unintentionally pushed into the sealing space S1 beyond the design target position. Such a situation may occur, for example, due to worker error during the assembly of the main seal member 24. In addition, it may occur due to vibration during the transportation of the rotating machine 12 to which the main seal member 24 is assembled. As a result, the main seal member 24 may interfere with the inner seal member 26, leading to a malfunction. A malfunction here refers to a situation where, for example, the main seal member 24 comes into contact with the inner lip portion 46 of the inner seal member 26, causing the inner lip portion 46 to shift from its design target position and preventing it from performing the required sealing function. For example, the inner lip portion 46 may separate from the inner seal surface 52, or the overlap of the inner lip portion 46 with respect to the inner seal surface 52 may change, potentially preventing it from performing the required sealing function.

[0026] According to the seal structure 10 of this embodiment, the positioning unit 54 positions the main seal member 24 axially relative to the outer member 14, thereby restricting the axial movement of the main seal member 24 toward the sealing space side S1. This makes it possible to better avoid situations where the main seal member 24 is unintentionally pushed further toward the sealing space side S1 than the design target position, causing interference with the inner seal member 26. Consequently, it is possible to avoid the occurrence of problems caused by such interference.

[0027] The positioning portion 54 is formed by a stepped portion 56 provided on the outer member 14. Therefore, the number of parts can be reduced compared to the case where the positioning portion 54 is formed by a separate component from the outer member, such as a retaining ring.

[0028] The inner seal member 26 includes an inner lip portion 46 that contacts the inner seal surface 52 provided on the outer member 14. This allows the inner seal member 26 to isolate the gap space 42 from the sealed space 20. Consequently, the foreign matter blocking effect of the inner seal member 26 can be improved, which is advantageous in preventing foreign matter from entering between the main lip portion 30 and the main seal surface 40.

[0029] (A) Let's consider the case where the main sealing surface 40 is formed by the outer circumferential surface of the inner member 16 while maintaining the shape of the inner sealing member 26. In this case, it is necessary to shift the inner sealing member 26 toward the sealing space side S1, which leads to an increase in the axial dimension of the seal unit 18. In this respect, when the main sealing surface 40 is formed by the second mounting portion 50 of the inner sealing member 26, the inner sealing member 26 can be brought closer to the non-sealing space side S2 compared to when the main sealing surface 40 is formed by the inner member 16. Consequently, this is advantageous in reducing the axial dimension of the seal unit 18.

[0030] Next, other features of the seal structure 10 will be described. The second radially extending portion 48 of the inner seal member 26 comprises an inner surface 48a facing the sealing space side S1 and an outer surface 48b facing the non-sealing space side S2. At least a portion of the inner surface 48a and the outer surface 48b constitutes the inner lip portion 46.

[0031] An inner beveled portion 48c is provided at the tip of the inner surface 48a, extending radially outward toward the sealing space S1. In this embodiment, the inner beveled portion 48c is curved in the cross-section along the axial direction. It may also be planar, or a combination of curved and planar shapes. When forming a curved shape, it may be composed of a single radius of curvature, or it may be composed of a combination of curved surfaces with multiple radii of curvature. The inner surface 48a is provided with an inner planar portion 48d that extends radially inward from the inner beveled portion 48c. The inner planar portion 48d is planar in the cross-section along the axial direction, extending radially. When forming a planar or curved shape in this way, the surface of these planar or curved parts may be provided with irregularities indicating product information (e.g., model number). In other words, irregular irregularities in the circumferential direction may be provided on the surface of these planar or curved portions. In other words, irregular irregularities that are not continuous and are not regular may be provided on the surface of these planar or curved portions. Let L1 be the maximum axial dimension from the inner surface 48a to the outer surface 48b of the second radially extending portion. Here, "planar" means, for example, a shape that is straight along the radial direction in a cross-section along the axial direction, as well as a shape that is slightly concave and curved inward toward the non-sealing space side S2 by a dimension of 5% or less of dimension L1, or a combination of these.

[0032] The tip of the outer surface 48b is provided with an outer beveled portion 48e that extends radially outward toward the sealing space S1. In this embodiment, the outer beveled portion 48e has a curved shape in the cross-section along the axial direction. It may also have a planar shape, or a shape that combines a curved shape and a planar shape. The outer surface 48b is provided with an outer planar portion 48f that extends radially inward from the inner beveled portion 48c. The outer planar portion 48f has a planar shape that extends radially in the cross-section along the axial direction.

[0033] Regarding the shape of the inner surface 48a, the condition that it is a shape combining the inner flat portion 48d and the inner inclined portion 48c, or a shape consisting only of the inner inclined portion 48c, is called the first shape condition. In this embodiment, the inner surface 48a satisfies the first shape condition at the tip-side portion 48g of the second radially extending portion 48. Here, "tip-side portion 48g" refers to the portion of the inner surface 48a of the second radially extending portion 48 that is on the tip side of the radial central position P1. The position that divides the radial dimension of the inner surface 48a of the second radially extending portion 48 into four equal parts in the radial direction, and is radially inward from the central position P1, is called the inner quadrilateral position P2. In this case, the inner surface 48a of this embodiment also satisfies the first shape condition radially outward from the inner quadrilateral position P2. In this embodiment, the inner surface 48a is a shape combining the inner flat portion 48d and the inner inclined portion 48c, but it may also be a shape consisting only of the inner inclined portion 48c. When this first shape condition is met, the inner surface 48a will not have a recess formed in the portion that satisfies the condition, which recesses into the non-sealing space S2 on the way to the radially outward side.

[0034] Regarding the shape of the outer surface 48b, the condition that it is a shape combining the outer flat portion 48f and the outer slope portion 48e, or a shape consisting only of the outer slope portion 48e, is called the second shape condition. In this embodiment, the outer surface 48b satisfies the second shape condition at the tip portion 48g of the second radially extending portion 48. In this embodiment, the outer surface 48b satisfies the second shape condition radially outward from the inner quadrilateral position P2. In this embodiment, the outer surface 48b is a shape combining the outer flat portion 48f and the outer slope portion 48e, but it may also be a shape consisting only of the outer slope portion 48e. When this second shape condition is satisfied, in the portion of the outer surface 48b that satisfies the condition, no recess is formed that recesses into the sealing space side S1 on the way to the radially outward side.

[0035] Refer to Figure 2. The effects of the above features will now be explained. The inner seal member 26 is rotatable together with the inner member 16. This allows the lubricant that has come into contact with both axial sides of the inner seal member 26 to be propelled radially outward by centrifugal force along with foreign matter, thereby exhibiting a sweep-off effect. Here, the sweep-off effect is indicated by an arrow in the direction to which the centrifugal force is transmitted to the inner seal member 26. This makes it possible to keep foreign matter present around the inner seal member 26 away from the main lip portion 30, making it difficult for foreign matter to reach the main lip portion 30. The foreign matter present around the inner seal member 26 here includes not only foreign matter on the sealing space side S1 relative to the inner seal member 26, but also foreign matter in the gap space 42.

[0036] An inner inclined surface portion 48c is provided at the tip of the inner surface 48a of the second radially extending portion 48. This allows the lubricant that is swept away from the inner inclined surface portion 48c of the inner seal member 26 to have a velocity component on the sealing space side S1, thereby pushing the lubricant back in the direction D of the sealing space side S1 along with the foreign matter. Consequently, it becomes more difficult for foreign matter to flow to the non-sealing space side S2 via the space between the tip of the second radially extending portion 48 of the inner seal member 26 and the outer member 14, thereby improving the foreign matter blocking effect of the inner seal member 26.

[0037] Let's consider the case where, in the tip portion 48g of the second radially extending portion 48, a recess is formed on the inner surface 48a that is recessed toward the non-sealing space side S2. In this case, as the lubricant is propagated radially outward along the inner surface 48a by centrifugal force, the lubricant is also propagated axially toward the non-sealing space side S2 in the recess. As a result, the velocity component of the lubricant that is swept away from the inner inclined surface portion 48c of the inner seal member 26 toward the sealing space side S1 becomes smaller, and the improvement in the foreign matter blocking effect due to the swept-away effect becomes smaller.

[0038] In this regard, the inner surface 48a of this embodiment has a shape that satisfies the aforementioned first shape condition at the tip end portion 48g of the second radially extending portion 48, and no recess is formed at the tip end portion 48g that recesses toward the non-sealing space side S2. Therefore, in the process of the lubricant being transmitted radially outward along the inner surface 48a by centrifugal force, it is possible to avoid the situation in which the lubricant is transmitted toward the non-sealing space side S2 at the tip end portion 48g. As a result, it is possible to avoid the situation in which the velocity component of the lubricant that is swept away from the inner inclined surface portion 48c of the inner seal member 26 toward the sealing space side S1 becomes small due to the lubricant being transmitted toward the non-sealing space side S2 in this way. Consequently, it is possible to maintain a large velocity component of the lubricant that is swept away by the swept-away effect toward the sealing space side S1, which is advantageous in improving the foreign matter blocking effect due to the swept-away effect.

[0039] Even if foreign matter is present in the gap space 42 along with the lubricant, the foreign matter that flows radially outward within the gap space 42 due to the sweeping effect can be discharged from the gap space 42 to the sealing space side S1 through the space between the inner seal member 26 and the outer member 14. Let's consider the case where a recess is formed on the outer surface 48b of the tip portion 48g of the second radially extending portion 48, which is recessed toward the sealing space side S1. In this case, as the foreign matter flows to be discharged from the gap space 42 in this manner, the recess on the outer surface 48b restrains the foreign matter, making it difficult to discharge the foreign matter from the gap space 42 to the sealing space 20 side.

[0040] In this regard, the outer surface 48b of this embodiment has a shape that satisfies the aforementioned second shape condition at the tip end portion 48g of the second radially extending portion 48, and no recess is formed at the tip end portion 48g that recesses into the sealing space side S1. Therefore, it is possible to avoid a situation in which foreign matter that is about to be discharged from the gap space 42 through the gap between the inner seal member 26 and the outer member 14 is restrained by the recess of the outer surface 48b, which is advantageous for discharging foreign matter from the gap space 42 to the sealing space side S1.

[0041] (Second Embodiment) Refer to Figure 3. Next, we will move on to the description of other embodiments. In the following embodiments, the same content as in the first embodiment may apply to components described in the first embodiment but not described below.

[0042] The seal structure 10 of this embodiment differs from the seal structure 10 of the first embodiment mainly in the main seal surface 40 and the inner seal member 26. Specifically, in the first embodiment, the main seal surface 40 was formed by the second mounting portion 50 of the inner seal member 26. Instead, in this embodiment, the main seal surface 40 is formed by the inner member 16. In this embodiment, the main seal surface 40 is formed by the outer peripheral surface of the inner member 16. The entire inner seal member 26 of this embodiment is positioned offset S1 toward the sealing space side relative to the main seal member 24. It can also be said that the inner seal member 26 is provided in a position that does not overlap with the main seal member 24 when viewed from the radial direction.

[0043] Let's consider the case where the main sealing surface 40 is formed by the second mounting portion 50 of the inner sealing member 26 while maintaining the shape of the main sealing member 24. In this case, it is necessary to shift the position of the main sealing member 24 radially outward, which leads to an increase in the radial dimension of the sealing unit 18. In this respect, when the main sealing surface 40 is formed by the inner member 16, the main sealing member 24 can be brought radially closer to the inner member 16 compared to when the main sealing surface 40 is formed by the second mounting portion 50 of the inner sealing member 26. Consequently, this is advantageous in reducing the radial dimension of the sealing unit 18. In addition, according to this embodiment, the same effects as the first embodiment can be obtained, except for (A) mentioned above.

[0044] (Third Embodiment) Refer to Figure 4. Next, the details of the rotating machine 12 will be described. Here, an overview of the rotating machine 12 in the third and fourth embodiments will be given, and then the features related to the seal structure 10 described above will be explained.

[0045] The rotating machine 12 is incorporated into a master machine. The master machine is, for example, at least part of various machines such as (1) industrial machinery such as machine tools and construction machinery, (2) robots such as industrial robots and service robots, (3) transport equipment such as conveyors, and (4) vehicles. The rotating machine 12 in this embodiment is equipped only with a reduction gear 60. The reduction gear 60 can drive a driven body (not shown) that is part of the master machine by reducing the input rotation and outputting that reduced rotation.

[0046] The gearbox 60 in this embodiment includes an input member 62 to which rotation output from a prime mover (not shown) is input, a reduction mechanism 64 for reducing the rotation of the input member 62, a gearbox casing 66 that houses at least a part of the reduction mechanism 64, and carriers 68A and 68B arranged inside the gearbox casing 66. In this embodiment, the gearbox 60 uses a center crank type eccentric oscillating reduction mechanism 64. In this embodiment, the carrier 68A becomes an output member 70 that outputs the rotation transmitted from the reduction mechanism 64 to the driven body. Alternatively, the gearbox casing 66 may also be the output member 70.

[0047] The input member 62 may receive rotation output from the prime mover directly, or it may receive rotation via another power transmission member. The prime mover is, for example, a motor or an engine. The reduction gear 60 using a center-crank type eccentric oscillating reduction mechanism includes a crankshaft 74 having an eccentric portion 72 as the input member 62. The crankshaft 74 is positioned on the rotational centerline C70 of the output member 70. The crankshaft 74 has at least one (two in this case) eccentric portion 72. The eccentric portion 72 has a circular shape that is eccentric with respect to the rotational centerline C74 of the crankshaft 74.

[0048] The reduction gear 64 has an external gear 76 and an internal gear 78 that mesh with each other. In this embodiment, the external gear 76 is provided corresponding to an eccentric portion 72 and is pivotable by the corresponding eccentric portion 72. An eccentric bearing 80 is positioned between the external gear 76 and the eccentric portion 72. In this embodiment, the internal gear 78 is provided on the inner circumference of the reduction gear casing 66, and the reduction gear casing 66 also serves as the internal gear.

[0049] In this embodiment, the gearbox casing 66 houses the external gear 76 of the reduction mechanism 64. If the gearbox casing 66 and the internal gear 78 are separate components, the gearbox casing 66 may also house the internal gear 78 in addition to the external gear 76.

[0050] The carriers 68A and 68B are rotatable relative to the reduction gear casing 66 when the reduction gear 60 is in operation. A main bearing 82 supporting the output member 70 is positioned between the reduction gear casing 66 and the carriers 68A and 68B. The carriers 68A and 68B are synchronous with the rotational component of the external gear 76. To achieve this, a pin 84 protrudes from one of the carriers 68A, passing through the external gear 76 in the axial direction. The pin 84 indirectly contacts the external gear 76 via a roller 86, enabling synchronization of the rotational component of the external gear 76 with the carrier 68A. Alternatively, the pin 84 may directly contact the external gear 76. The carriers 68A and 68B in this embodiment include a first carrier 68A and a second carrier 68B positioned on both axial sides relative to the reduction mechanism 64. The first carrier 68A and the second carrier 68B are connected via the pin 84 using bolts or the like.

[0051] An example of the operation of the rotating machine 12 described above will now be explained. When the rotation output from the prime mover is input to the input member 62, the input member 62 rotates. When the input member 62 rotates, its rotation is reduced by the reduction mechanism 64 and then transmitted to the output member 70, and the rotation of the output member 70 is output from the output member 70 to the driven body. At this time, the rotation of the output member 70 is reduced compared to the rotation of the input member 62.

[0052] In this embodiment, when the crankshaft 74, which is the input member 62, rotates, the external gear 76 oscillates due to its eccentric portion 72. As the external gear 76 oscillates, the meshing position between the external gear 76 and the internal gear 78 changes in the circumferential direction. Consequently, one of the external gear 76 and the internal gear 78 (in this case, the external gear 76) rotates, and its rotational component is transmitted to the output member 70, which then outputs to the driven body.

[0053] (Fourth Embodiment) Refer to Figure 5. In this embodiment, the rotating machine 12 includes, in addition to the reduction gear 60, a prime mover 90, an adapter 92 connecting the prime mover 90 and the reduction gear 60, and a disc-shaped driven body 94 driven by the reduction gear 60. Thus, the rotating machine 12 may include only the reduction gear 60, or it may include, in addition to the reduction gear 60, one or more of the prime mover 90, adapter 92, and driven body 94.

[0054] The prime mover 90 in this embodiment is a motor. The prime mover 90 comprises a prime mover casing 96 and a drive shaft 98 for outputting the rotation generated inside the prime mover 90. The prime mover casing 96 is connected to a reduction gear casing 66 via an adapter 92. In this embodiment, an intermediate shaft 100 is connected to the drive shaft 98 using a key or the like so that it can rotate integrally with the drive shaft 98. An input pinion 102 is provided on the intermediate shaft 100.

[0055] In this embodiment, the reducer 60 uses a distribution-type eccentric oscillation-type reduction mechanism 64. Multiple crankshafts 74 (only one is shown here) of the reducer 60 using this reduction mechanism 64 are provided at positions radially offset with respect to the rotation centerline C70 of the output member 70. Each of the multiple crankshafts 74 is provided with a crankshaft gear 104 that meshes with an input pinion 102 and is rotatable as a whole. The input pinion 102 and the crankshaft gear 104 constitute a pre-stage reduction mechanism 106 that can reduce the rotation of the intermediate shaft 100 and transmit it to the crankshafts 74. Rotation is input to each of the multiple crankshafts 74 from the drive shaft 98 via the pre-stage reduction mechanism 106. In this embodiment, the reducer 60 has a reducer casing 66 connected to an external support member 108, and the rotating machine 12 including the reducer casing 66 is supported by the support member 108.

[0056] An example of the operation of the rotating machine 12 described above will now be explained. The rotation output from the driving shaft 98 of the prime mover 90 is reduced via the pre-reduction mechanism 106 and then input to the crankshaft 74, which is the input member 62. When the input member 62 rotates, its rotation is further reduced by the reduction mechanism 64 and then transmitted to the output member 70, and the rotation of the output member 70 is output from the output member 70 to the driven body 94. Since the other aspects are the same as the third embodiment, the explanation will be omitted.

[0057] (Third / Fourth Embodiment) Next, features related to the seal structure of the rotating machine 12 described in the third and fourth embodiments will be explained. In the rotating machine 12 of each embodiment, seal structures 10-A to 10-E are used at multiple locations on the rotating machine 12, but the seal structure 10 of this disclosure only needs to be used at least at one location on the rotating machine 12. To distinguish the multiple seal structures 10-A to 10-E from some related components, letters such as "-A", "-B", and "-C" may be added to the end of the reference numerals.

[0058] Refer to the third embodiment in Figure 4. The seal structures 10-A to 10-D of this embodiment include a first seal structure 10-A used for the input member 62 and the first carrier 68A, a second seal structure 10-B used for the input member 62 and the second carrier 68B, a third seal structure 10-C used for the reducer casing 66 and the first carrier 68A, and a fourth seal structure 10-D used for the reducer casing 66 and the second carrier 68B.

[0059] In the first seal structure 10-A, the outer member 14-A becomes the first carrier 68A, and its inner member 16-A becomes the input member 62. In the second seal structure 10-B, the outer member 14-B becomes the second carrier 68B, and its inner member 16-B becomes the input member 62. In the third seal structure 10-C, the outer member 14-C becomes the reducer casing 66, and its inner member 16-C becomes the first carrier 68A. In the fourth seal structure 10-D, the outer member 14-D becomes the reducer casing 66, and its inner member 16-D becomes the second carrier 68B.

[0060] Refer to the fourth embodiment in Figure 5. The seal structures 10-C and 10-E of this embodiment include, in addition to the third seal structure 10-C described above, a fifth seal structure 10-E used in the relay shaft 100 and the adapter 92. The outer member 14-E of the fifth seal structure 10-E becomes the adapter 92, and its inner member 16-E becomes the relay shaft 100. A seal unit 18 is arranged between the outer members 14-A to 14-E and the inner members 16-A to 16-E of each seal structure 10-A to 10-E.

[0061] At least one of the outer members 14 and inner members 16 of different seal structures 10 may be common. For example, in the third embodiment of Figure 4, the inner member 16-A of the first seal structure 10-A and the inner member 16-B of the second seal structure 10-B become a common input member 62. Also, what is an outer member 14 in one seal structure 10 may become an inner member 16 in another seal structure 10. For example, the first carrier 68A, which is the outer member 14-A of the first seal structure 10-A, becomes the inner member 16-C of the third seal structure 10-C. The combinations of outer members 14 and inner members 16 constituting the seal structure 10 of the rotating machine 12 given here are merely examples, and specific examples are not particularly limited.

[0062] When the seal structure 10 is applied to multiple locations on the rotating machine 12, the orientation of each direction used to identify the components of each seal structure 10 may differ for each location where the seal structure 10 is applied. For example, in the third embodiment of Figure 4, in the first seal structure 10-A, the right side of the paper is the side with the sealing space 20 in the axial direction, but in the second seal structure 10-B, the left side of the paper may be the side with the sealing space 20 in the axial direction.

[0063] The rotating machine 12 is provided with a sealed space 20 that is sealed by at least one seal unit 18 constituting a seal structure 10. In the third embodiment, the sealed space 20 is sealed by four seal units 18 constituting seal structures 10-A to 10-D. In the fourth embodiment, the sealed space 20 is sealed not only by the two seal units 18 constituting the seal structures 10, but also by a driven body 94 that closes the through holes 68a formed in the carriers 68A and 68B. The sealed space 20 may also be sealed using a sealing member other than the seal units 18. Thus, the number of seal units 18 that seal the sealed space 20 is not particularly limited, and the sealed space 20 may be sealed using elements other than the seal units 18 of the rotating machine 12.

[0064] The sealing space 20 may be provided only inside the reducer casing 66 of the reducer 60, as in the third embodiment. In addition, the sealing space 20 may be continuous not only inside the reducer 60 but also inside other components such as the adapter 92 connected to the reducer 60, as in the fourth embodiment. The entire sealing space 20 may be provided inside the rotating machine 12, as in the third and fourth embodiments. In addition, the sealing space 20 may be continuous not only inside the rotating machine 12 but also inside other components connected to the rotating machine 12.

[0065] The sealed space 20 contains lubricated elements that are lubricated by a lubricant. These lubricated elements include, for example, the meshing points of the gear pairs constituting the reduction mechanism 64 in the third embodiment, as well as the rolling points of the rolling elements of the bearings. Here, bearings refer to eccentric bearings 80, main bearings 82, etc. Furthermore, in the fourth embodiment, the lubricated elements also include the meshing points of the gear pairs constituting the preceding reduction mechanism 106. Focusing on the gear pairs, it can be said that at least a part of the reduction mechanism 64 is located in the sealed space 20. The specific examples of lubricated elements are not particularly limited.

[0066] At least one inner member 16 of the seal structure 10 becomes a high-speed shaft 110 that rotates at a higher speed than the output member 70 of the reduction gear 60. In the third embodiment shown in Figure 4, the input members 62, which are the inner members 16-A and 16-B of the first seal structure 10-A and the second seal structure 10-B, become the high-speed shaft 110. In the fourth embodiment shown in Figure 5, the relay shaft 100, which is the inner member 16-E of the fifth seal structure 10-E, becomes the high-speed shaft 110. The specific example of the high-speed shaft 110 is not particularly limited, and in addition to the input member 62, it may also be a driving shaft 98, etc.

[0067] As a result, the inner seal member 26 of the seal structure 10 is attached to the inner member 16, which becomes the high-speed shaft 110. Therefore, compared to the case where the inner seal member 26 is attached to the output member 70, the rotational speed of the inner seal member 26 can be increased, and the aforementioned swing-off effect can be effectively exerted. In turn, the swing-off effect is advantageous in keeping foreign matter present around the inner seal member 26 away from the main lip portion 30.

[0068] Next, we will describe the transformation forms of each component described so far.

[0069] The main sealing member 24 is provided with a main lip portion 30 that contacts the main sealing surface 40 and is only required to be able to close the gap between the outer member 14 and the inner member 16; its specific configuration is not particularly limited.

[0070] The inner seal member 26 only needs to be able to block foreign matter from flowing from the sealed space side S1 to the main seal member 24 side, and its specific configuration is not particularly limited. For example, the inner seal member 26 does not need to have an inner lip portion 46 that contacts the outer member 14.

[0071] The direction in which the second mounting portion 50 of the inner seal member 26 extends in the axial direction, or whether or not it extends at all, is not particularly important. For example, the second mounting portion 50 may extend toward the sealing space side S1 relative to the second radially extending portion 48. Also, if the axial dimension of the second radially extending portion 48 of the inner seal member 26 is thick enough to allow attachment to the inner member 16 by interference fit or the like, the second mounting portion 50 does not need to extend toward both sides in the axial direction relative to the second radially extending portion 48. In this case, the second mounting portion 50 will be formed by the radially inner end of the second radially extending portion 48.

[0072] The inner seal member 26 does not necessarily have to be rotatable with the inner member 16. In this case, it is sufficient that the main seal member 24 is rotatable with the outer member 14. The shapes of the inner surface 48a and outer surface 48b of the inner seal member 26 are not particularly limited. For example, the tip of the inner surface 48a of the inner seal member 26 does not necessarily have to have an inner bevel 48c. To achieve this, for example, the tip of the inner surface 48a may have a bevel that extends radially outward toward the non-sealing space side S2. Also, the inner surface 48a may have a recess formed in the tip portion 48g of the second radially extending portion 48 that recesses toward the non-sealing space side S2. The outer surface 48b of the inner seal member 26 may have a recess formed in the tip portion 48g of the second radially extending portion 48 that recesses toward the sealing space side S1.

[0073] The positioning portion 54 of the seal structure 10 may be composed of a retaining ring or the like attached to the inner circumference of the outer member 14.

[0074] Although an example of a rotating machine 12 equipped with a reduction gear 60 has been described, it may also be composed solely of a prime mover 90. The specific examples of the reduction mechanism 64 used in the reduction gear 60 are not particularly limited. If the reduction mechanism 64 is a gear mechanism, the gear mechanism may be an eccentric oscillating type reduction mechanism, a deflection meshing type reduction mechanism, or, for example, a simple planetary gear mechanism, a right-angle gear mechanism, a parallel-axis gear mechanism, etc. Furthermore, the specific type of deflection meshing type reduction mechanism is not particularly limited and may be cylindrical, top hat type, cup type, etc. The specific type of eccentric oscillating type reduction mechanism is not particularly limited and may be, for example, the aforementioned center crank type, distribution type, etc. Furthermore, the reduction mechanism 64 may be a friction transmission mechanism (traction drive), etc., in addition to a gear mechanism.

[0075] The contents of each component described in the embodiments above are illustrative. The abstract technical ideas derived from these should not be interpreted restrictively to the contents of this specification. Many design changes, such as modifications, additions, and deletions, are possible for the contents of each component described in the embodiments. Such modifications are emphasized with the notations "this form" and "embodiment." However, design changes are also permitted for contents without such notations. Any combination of the above components is also valid. For example, any explanatory items from other embodiments may be combined with an embodiment, and any explanatory items from an embodiment and other variants may be combined with a variant. Components composed of a single member in the description herein may be composed of multiple members. Similarly, components composed of multiple members may be composed of a single member. [Explanation of Symbols]

[0076] 10...Seal structure, 12...Rotating machine, 14...Outer member, 16...Inner member, 18...Seal unit, 20...Sealing space, 24...Main seal member, 26...Inner seal member, 30...Main lip portion, 40...Main seal surface, 46...Inner lip portion, 48...Radial extension portion, 48a...Inner surface, 48b...Outer surface, 48c...Inner inclined surface portion, 48d...Inner flat portion, 48e...Outer inclined surface portion, 48f...Outer flat portion, 48g...Tip portion, 52...Inner seal surface, 54...Positioning portion, 56...Step portion, 60...Reduction gear, 70...Output member, 110...High-speed shaft.

Claims

1. An outer member and an inner member that are rotatable relative to each other, A seal structure comprising: a seal unit disposed between the outer member and the inner member for sealing a sealing space provided on one side in the axial direction, The aforementioned seal unit is A main seal member having a main lip portion that contacts the main seal surface provided on the inner member, and attached to the outer member, The system comprises an inner seal member which is positioned at least a portion of the main seal member on one axial side and attached to the inner member, A seal structure comprising a positioning portion provided separately from the inner seal member for positioning the main seal member in the axial direction relative to the outer member.

2. The sealing structure according to claim 1, wherein the positioning portion is provided by a stepped portion on the inner circumference of the outer member.

3. The seal structure according to claim 1, wherein the inner seal member is rotatable together with the inner member.

4. The inner seal member has a radially extending portion that extends in the radial direction, The radially extending portion has an inner surface facing the sealing space side in the axial direction, The seal structure according to claim 3, wherein the tip of the inner surface is provided with an inner inclined surface portion that extends axially toward the sealing space as it extends radially outward.

5. The seal structure according to claim 4, wherein the inner surface has a shape consisting only of the inner inclined surface at the tip end of the radially extending portion, or a shape combining an inner flat portion extending along the radial direction and the inner inclined surface.

6. The inner seal member has a radially extending portion that extends in the radial direction, The radially extending portion has an outer surface facing the opposite side in the axial direction from the sealing space, The seal structure according to claim 3, wherein the outer surface has a shape consisting only of an inner inclined surface that extends axially toward the sealing space as it moves radially outward in the tip portion of the radially extending portion, or a shape combining an inner flat portion that extends radially outward and the inner inclined surface.

7. The seal structure according to claim 1, wherein the inner seal member comprises an inner lip portion that contacts the inner seal surface provided on the outer member.

8. The inner seal member is provided with a mounting portion that is attached to the inner member, The sealing structure according to claim 1, wherein the main sealing surface is formed by the mounting portion.

9. The sealing structure according to claim 1, wherein the main sealing surface is composed of the inner member.

10. A rotating machine using the seal structure described in claim 1.

11. The rotating machine equipped with a reduction gear, The rotating machine according to claim 10, wherein at least one of the inner members of the seal structure is a high-speed shaft that rotates at a higher speed than the output member of the reduction gear.

Images