JP2004301276A - Grease sealing structure of transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grease sealing structure of a transmission for improving durability of an oil seal regardless of a kind of grease sealed in a casing. <P>SOLUTION: This grease sealing structure 12 has a shield-like member 42 for regulating the movement of the grease between a rolling body 38 of a bearing 32 and the oil seal 40 in an empty space 32A of the bearing 32. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a grease sealing structure for a transmission used in the fields of, for example, industrial equipment and transportation equipment.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a transmission having a structure in which a transmission mechanism such as a gear transmission mechanism is housed in a casing is often used in industrial equipment, transportation equipment, and the like. In such a transmission, a lubricant for lubricating the transmission mechanism is generally enclosed in a casing. As the lubricant, a liquid lubricating oil or grease is used, and such a lubricant generally contains various additives for achieving good lubrication.
[0003]
The transmission is provided with an oil seal to seal the lubricant in the casing. The oil seal slides against a member such as a shaft of the transmission mechanism at the lip portion to prevent leakage of the lubricant, and in order to reduce the wear of the lip portion, the run-out of the mating member in sliding contact is minimized. This is very important.
[0004]
Therefore, the oil seal is generally provided near a bearing for rotatably supporting a mating member with which the oil seal slides. In other words, generally, a bearing for rotatably supporting a mating member with which the oil seal slides is disposed near the oil seal (for example, see Patent Document 1). As the bearing, for example, a roller bearing, a ball bearing, or the like having an inner ring, an outer ring, and a rolling element is often used. Generally, lubrication oil or grease common to the transmission mechanism is used for lubrication of the bearings.
[0005]
Such a lubricant sealing structure using an oil seal is widely used in many transmissions regardless of the type of lubricating oil and grease.
[0006]
[Patent Document 1]
JP-A-2002-130390 (FIG. 2)
[0007]
[Problems to be solved by the invention]
However, in recent years, the performance required for transmissions has become extremely severe, and the power transmission parts (gears, shafts, bearings) of the transmission have been made more compact and longer life, and the durability of the lip part of the oil seal has also been improved. Is required.
[0008]
However, there is a problem that the characteristics of the grease for improving the performance of the power transmission portion (determined by the base oil thickener, additives, etc.) and the characteristics of the grease for improving the performance of the oil seal do not always match. . That is, even if grease that contributes to extending the life of the power transmission unit is used, the durability of the lip portion of the oil seal does not always improve.
[0009]
If grease that contributes to extending the life of the lip portion of the oil seal is used, desired lubrication cannot be obtained for the transmission mechanism, and the durability of the power transmission unit may be reduced.
[0010]
The present invention has been made in view of the above problems, and has a grease sealing structure for a transmission that can improve the durability of an oil seal regardless of the type of grease sealed in a casing. The task is to provide.
[0011]
[Means for Solving the Problems]
The present invention includes a transmission mechanism, a casing for housing grease for lubricating the transmission mechanism, an oil seal for sealing the grease in the casing, an inner ring, an outer ring, and a rolling element. And a bearing rotatably supporting the transmission mechanism in the vicinity of the oil seal. Grease sealing structure of a transmission, wherein one of the inner ring and the outer ring is the oil seal more than the other as the bearing. A bearing having an empty space protruding to the side, and a shield-like member for restricting movement of the grease between the rolling element of the bearing and the oil seal is provided in the empty space of the bearing. As a result, the above problem has been solved.
[0012]
That is, by providing a shield-like member for regulating the movement of grease between the rolling element of the bearing and the oil seal, the amount of wear powder and the like reaching the oil seal together with the grease can be reduced. In addition, regardless of the type of the additive contained in the grease, the deterioration of the lip portion of the oil seal due to the grease can be suppressed, and the durability of the oil seal can be improved.
[0013]
Furthermore, since grease suitable for lubrication of the transmission mechanism can be used, the durability of the transmission mechanism can also be improved.
[0014]
Also, since the shield-like member is arranged on the oil seal side of the bearing's rolling element, grease is sufficiently supplied to the bearing, and the grease is blocked by the shield-like member and easily stays around the bearing. Also, the effect of improving the durability of the bearing can be obtained.
[0015]
In addition, since the shield-like member is attached by utilizing the empty space of the bearing, it is not necessary to provide a special space for the shield-like member, and the transmission can be made more compact.
[0016]
The shield-shaped member is attached to the other of the outer ring and the inner ring of the bearing so that the shield-shaped member rotates relatively close to a member connected to one of the outer ring and the inner ring of the bearing to form a labyrinth. Good.
[0017]
By arranging the shield member so as to form the labyrinth, the grease that touches the oil seal and the grease used for lubricating the transmission and containing wear powder can be reliably separated. As a result, the durability of the oil seal can be reliably improved. Furthermore, since the shield member does not contact the member on the other side, the durability of the shield member itself is also improved. In addition, as a counterpart member to which the shield-shaped member approaches, not a part of the bearing but, for example, a member such as a casing coupled to an outer ring or an inner ring of the bearing is used, so that the degree of freedom in designing the shield-shaped member is high. Therefore, it is possible to provide a shield-shaped member having a suitable configuration for restricting the movement of the grease.
[0018]
Further, the shield-shaped member may be attached to the other of the outer ring and the inner ring of the bearing such that the shield member slides on a member connected to one of the outer ring and the inner ring of the bearing and relatively rotates. In this case, the sliding portion of the shield-shaped member may be formed of a rubber member.
[0019]
Thus, by disposing the shield member so as to be in sliding contact with another member, the movement of grease can be reduced more reliably, and the durability of the oil seal can be further improved. In particular, by using a rubber member for the sliding contact portion, a greater shielding effect can be obtained, the movement of grease can be significantly reduced, and an effect of reducing wear of the sliding contact portion can also be obtained. In this case, also, as a mating member with which the shield member slides, not a part of the bearing but, for example, a member such as a casing connected to an outer ring or an inner ring of the bearing is used to design the shield member. The degree of freedom is increased, and a shield-like member having a suitable configuration for restricting the movement of grease can be provided.
[0020]
Here, whether to arrange the shield-shaped member so as to be close to another member or to be slidably contacted with another member depends on the material and shape of the oil seal, the shield-shaped member, and compatibility with grease. Considering the durability and the like of the oil seal and the shield-shaped member in consideration of the above, the selection may be made as appropriate.
[0021]
Further, the shield-like member may be attached to the casing.
[0022]
As described above, by attaching the shield-like member to the casing, the degree of freedom in designing the shield-like member can be further increased. Further, in this case, the shield-shaped member may be attached so as to be close to or in sliding contact with the inner ring and the outer ring of the bearing that rotate relative to the casing.
[0023]
Further, the shield-like member has a ring plate-shaped partition portion for separating the rolling element of the bearing and the oil seal, and a cylindrical portion projecting axially from one of the inner periphery and the outer periphery of the partition portion. And an annular body having an L-shaped cross section.
[0024]
An annular body having an L-shaped cross section can be fitted to an outer ring or an inner ring of a bearing using a cylindrical portion, for example, and can be easily mounted on a transmission. Further, it is easy to fit into a member such as a casing connected to the outer ring or the inner ring of the bearing. Further, the annular body having an L-shaped cross section can be easily manufactured by, for example, press working, so that the productivity is good and the cost is low.
[0025]
Further, the shield-like member has a ring plate-shaped partition portion for separating the rolling element of the bearing and the oil seal, and an inner cylindrical portion projecting from the inner periphery of the partition portion to the rolling element side in the axial direction. And an outer cylindrical portion protruding from the outer periphery of the partition portion to the rolling element side in the axial direction.
[0026]
The annular body having a U-shaped cross section can be fitted to the outer ring or the inner ring of the bearing using the inner cylindrical portion or the outer cylindrical portion, for example, and is easily mounted on the transmission. Further, it is easy to fit into a member such as a casing connected to the outer ring or the inner ring of the bearing. Further, since the U-shape is open to the rolling element side, grease is stored inside the shield-shaped member, and the effect of restricting the movement of the grease is large. Further, by disposing the non-fixed sides of the inner cylindrical portion and the outer cylindrical portion so as to approach or slide against members such as the casing, the proximity area or the sliding contact area increases, thereby more reliably restricting the movement of the grease. can do. It should be noted that an annular body having a U-shaped cross section can be easily manufactured by, for example, press working, so that the productivity is good and the cost is low.
[0027]
It is preferable that the grease is sealed as a first grease, and a second grease is sealed between the shield-shaped member and the oil seal.
[0028]
Since the second grease is sealed between the shield member and the oil seal in this manner, the first grease can hardly penetrate, so that the amount of the first grease reaching the oil seal is significantly reduced. be able to.
[0029]
Further, since the lip portion of the oil seal can be lubricated with the second grease, the durability of the oil seal can be greatly improved. In particular, if a grease suitable for lubrication of the transmission mechanism is selected as the first grease and a grease suitable for lubrication of the oil seal is selected as the second grease, the durability of the entire transmission can be greatly improved. Can be improved.
[0030]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0031]
FIG. 1 is a side sectional view showing the entire structure of a transmission 10 according to the present embodiment. FIG. 2 is an enlarged side sectional view showing the grease sealing structure 12 of the transmission.
[0032]
Although the transmission 10 is characterized by the grease sealing structure 12, the overall structure of the transmission 10 will first be briefly described for understanding the present invention.
[0033]
The transmission 10 includes, as a transmission mechanism, an eccentric body shaft 16 having an eccentric body 14, an external tooth member 18 rotatably mounted on the eccentric body 14, and an internal tooth member 19 internally meshed with the external tooth member 18. And a carrier member 20 disposed on both sides of the external tooth member 18 and connected to the external tooth member 18 via means for transmitting only the rotation component of the external tooth member 18. An internal meshing planetary gear mechanism is provided, and grease is sealed inside as a lubricant.
[0034]
The eccentric body shaft 16 is rotatably supported by the carrier member 20 via two bearings 21 arranged on both sides of the external tooth member 18 in the axial direction.
[0035]
The eccentric body shaft 16 is integrally formed with three eccentric bodies 14 having a phase difference of 120 °. External teeth members 18 are attached to the respective eccentric bodies 14 via bearings 22. The external teeth members 18 are provided in three rows, thereby increasing the transmission capacity, maintaining the strength, and maintaining the rotational balance.
[0036]
External teeth (not shown) such as a trochoid tooth shape and an arc tooth shape are provided on the outer periphery of the external tooth member 18. The internal teeth member 19 is in mesh with the external teeth.
[0037]
The internal tooth member 19 is rotatably held by the casing 24 with a pin-shaped body.
[0038]
A plurality of inner roller holes 26 are formed in each outer tooth member 18 at appropriate intervals in the circumferential direction, and an inner roller 28 and an inner pin 30 are inserted into each inner roller hole 26, respectively.
[0039]
These inner pins 30 are connected to the carrier member 20 at both ends. The carrier member 20 is rotatably supported by the casing 24 via a bearing 32.
[0040]
An oil seal 40 constituting the grease sealing structure 12 is mounted outside the bearing 32 in a gap between the carrier member 20 and the casing 24, whereby the grease is sealed in the casing 24.
[0041]
The bearing 32 is a tapered roller bearing having an inner ring 34, an outer ring 36, and a rolling element 38. A part of the inner ring 34 projects toward the oil seal 40 from the outer ring 36, and a space is provided between the inner ring 34 and the case 24. It has a space 32A. Note that a part of the outer ring 36 also protrudes axially inward from the inner ring 34.
[0042]
Next, the grease sealing structure 12 will be described.
[0043]
The grease sealing structure 12 is characterized in that a shield-like member 42 for restricting movement of grease between the rolling element 38 of the bearing 32 and the oil seal 40 is provided in an empty space 32A of the bearing 32. I have.
[0044]
The shield-shaped member 42 has a ring-shaped partition wall 44 for separating the rolling element 38 and the oil seal 40, and a cylindrical portion 46 protruding in the axial direction from the partition 44, and has an L-shaped cross section. It is a ring body.
[0045]
The shield-like member 42 rotates relatively close to the casing 24 connected to the outer ring 36 of the bearing 32 on the outer periphery of the partition wall portion 44, and forms a labyrinth at the inner periphery of the cylindrical portion 46. The inner ring 34 is fitted.
[0046]
An annular projection 46A projecting radially inward is formed on the inner periphery of the cylindrical portion 46, and the annular projection 46A is fitted in an annular groove formed on the outer periphery of the inner ring 34 of the bearing 32. This prevents the shield-like member 42 from dropping off in the axial direction from the bearing 32.
[0047]
Next, the operation of the transmission 10 will be described.
[0048]
When the eccentric shaft 16 makes one rotation, each eccentric 14 also makes one rotation. When the eccentric body 14 makes one rotation, the respective external tooth members 18 also attempt to oscillate around the eccentric body shaft 14. The member 18 revolves slightly while rotating in contact with the internal tooth member 19.
[0049]
Now, for example, when the number of teeth of the external tooth member 18 is N and the number of teeth of the internal tooth member 19 is N + 1, the difference in the number of teeth is 1. Therefore, each time the eccentric shaft 14 rotates, the external tooth member 18 is shifted by one tooth with respect to the internal tooth member 19 integrated with the casing 24. That is, one rotation of the eccentric shaft 16 is transmitted to the external tooth member 18 at a reduced speed of -1 / N.
[0050]
The rotation of each external tooth member 18 is absorbed by the gap between the inner roller hole 26 and the inner roller 28, and only the rotation component is transmitted to the carrier member 20 via the inner pin 30.
[0051]
As a result, a speed reduction of 1 / N or a speed change of N is realized between the eccentric shaft 16 and the carrier member 20.
[0052]
Note that the carrier member 20 can be fixed and used as a transmission for increasing and decreasing the speed between the eccentric shaft 16 and the casing 24. Further, the eccentric shaft 16 can be fixed and used as a transmission for increasing and decreasing the speed between the carrier member 20 and the casing 24.
[0053]
The grease sealed in the transmission 10 is splashed and dispersed in the transmission 10 with the rotation of the external tooth member 18 and the like, and a part of the grease moves near the oil seal 40.
[0054]
Next, the operation of the grease sealing structure 12 will be described.
[0055]
The grease sealing structure 12 is provided between the rolling element 38 of the bearing 32 and the oil seal 40, and the bearing 32 includes the shield member 42 for restricting the movement of grease. The amount of grease moving to the oil seal 40 is reduced.
[0056]
In particular, since the shield member 42 is disposed close to the casing 24 so as to exhibit a labyrinth effect, the amount of grease reaching the oil seal 40 is reliably reduced. Accordingly, deterioration of the oil seal 40 due to wear powder contained in grease can be suppressed, and the transmission 10 has high durability of the oil seal 40.
[0057]
Further, since suitable grease can be used for lubrication of the transmission mechanism such as the external tooth member 18 and the bearing 32, the transmission 10 has high durability in the transmission mechanism such as the external tooth member 18 and the bearing 32. .
[0058]
Furthermore, since the shield member 42 does not contact the casing 24, the durability of the shield member 42 itself is high.
[0059]
Further, since the shield member 42 is disposed closer to the oil seal 40 than the rolling element 38 of the bearing 32, the amount of grease reaching the bearing 32 for the shield member 42 does not decrease. Since the grease is blocked by the shield member 42 and easily stays around the bearing 32, the durability of the bearing 32 of the transmission 10 is high.
[0060]
That is, the transmission mechanisms such as the oil seal 40, the shield-like member 42, the external tooth member 18, the bearing 32, and the like have high durability, and the transmission 10 has high reliability.
[0061]
Further, since the casing 24 coupled to the outer ring 36 of the bearing 32 is used as the mating member to which the shield-shaped member 42 comes close, not the bearing 32 itself, the degree of freedom in designing the shield-shaped member 42 is high.
[0062]
Further, since the shield-like member 42 is mounted by utilizing the empty space 32A of the bearing 32, and no special space is provided for the shield-like member 34A, the transmission 10 is so compact.
[0063]
Further, since the shield-like member 42 is an annular body having an L-shaped cross section, it is easy to fit the bearing 32 to the inner ring 34 in the cylindrical portion 46.
[0064]
Further, since the shield-shaped member 42 is an annular body having an L-shaped cross section, it can be easily manufactured by, for example, press working or the like, and the productivity is good, and the transmission 10 is inexpensive.
[0065]
Next, a second embodiment of the present invention will be described.
[0066]
FIG. 3 is an enlarged side sectional view showing a grease sealing structure 60 of the transmission according to the second embodiment.
[0067]
The grease sealing structure 60 is different from the grease sealing structure 12 according to the first embodiment in that a rubber member 62B is provided on the outer periphery of a partition 62A of a shield-like member 62, and the shield-like member 62 is formed of a casing in the rubber member 62B. 24 is provided so as to be in sliding contact therewith. Other configurations are the same as those of the grease sealing structure 12 of the first embodiment, and a description thereof will not be repeated.
[0068]
By disposing the shield-shaped member 62 so as to be in sliding contact with the casing 24, the movement of the grease to the oil seal 40 can be reduced more reliably than in the case of the labyrinth effect. The durability can be further improved. In particular, since the sliding portion is the rubber member 62B, the movement of the grease can be remarkably reduced, and even when the sliding contact occurs, the grease is hardly worn and the durability is high.
[0069]
Next, a third embodiment of the present invention will be described.
[0070]
FIG. 4 is an enlarged side sectional view showing the grease sealing structure 70 of the transmission according to the second embodiment.
[0071]
The grease sealing structure 70 is different from the grease sealing structure 12 according to the first embodiment in that the shield-like member 72 is provided with a ring plate-shaped partition wall portion 72A for separating the rolling element 38 of the bearing 32 and the oil seal 40. An inner cylindrical portion 72B protruding from the inner periphery of the partition wall portion 72A toward the rolling element 38 in the axial direction, and an outer cylindrical portion 72C protruding from the outer periphery of the partition wall portion 72A toward the rolling element 38 in the axial direction. It is characterized in that it is an annular body having a U-shaped cross section. Other configurations are the same as those of the grease sealing structure 12 of the first embodiment, and a description thereof will not be repeated.
[0072]
The shield-like member 72 is disposed so as to open toward the rolling element 38 and can accommodate grease inside the shield-like member 72, so that the effect of restricting the movement of grease is large. Furthermore, since the outer cylindrical portion 72C is arranged close to the casing 24 and has a large proximity area, the labyrinth effect for restricting the movement of the grease is large, and in this respect, the effect for restricting the movement of the grease is also large.
[0073]
Also, the annular body having a U-shaped cross section can be easily manufactured by, for example, press working or the like, similarly to the annular body having an L-shaped cross section. Good and low cost.
[0074]
In the first to third embodiments, the movement of the grease to the oil seal 40 is regulated only by the shield members 42, 62, and 72, respectively. However, the present invention is not limited to this. Grease for lubricating the speed change mechanism is sealed as a first grease on the meshing side closer to the tooth side than the shield-like members 42, 62, 72, and further, the shield-like members 42, 62, 72, the oil seal 40, The second grease may be sealed between the two.
[0075]
By sealing the second grease between the shield members 42, 62, 72 and the oil seal in this manner, the first seal is formed between the shield members 42, 62, 72 and the oil seal. Since almost no grease can enter, the amount of the first grease reaching the oil seal 40 can be significantly reduced. Further, since the lip of the oil seal 40 can be lubricated with the second grease, the durability of the oil seal 40 can be greatly improved.
[0076]
In particular, if a grease suitable for lubricating the transmission mechanism is selected as the first grease and a grease suitable for lubricating the oil seal is selected as the second grease, the durability of the transmission 10 can be improved as a whole. It can be greatly improved.
[0077]
In the first to third embodiments, the bearing 32 is a tapered roller bearing. However, the present invention is not limited to this, and one of the inner ring and the outer ring protrudes toward the oil seal side from the other. As long as the bearing has an empty space, another type of bearing such as a ball bearing may be used.
[0078]
The first to third embodiments show examples in which the grease sealing structures 12, 60, and 70 are applied to the transmission 10 including the eccentric oscillating type internally meshing planetary gear mechanism as the transmission mechanism. However, the present invention is not limited to this, and other types of gears such as a planetary gear, a spur gear, a helical gear, a bevel gear, a hypoid gear, a worm gear, etc. , A transmission mechanism including friction rollers, and a transmission mechanism including other types of transmission mechanisms such as a transmission mechanism including chains and sprockets.
[0079]
【The invention's effect】
As described above, according to the present invention, an excellent effect that the durability of an oil seal can be improved regardless of the type of grease sealed in a casing is provided.
[Brief description of the drawings]
FIG. 1 is a side sectional view showing an entire structure of a transmission according to a first embodiment of the present invention. FIG. 2 is an enlarged side sectional view showing a grease sealing structure of the transmission. FIG. 4 is an enlarged side sectional view showing a grease sealing structure of a transmission according to a second embodiment. FIG. 4 is an enlarged side sectional view showing a grease sealing structure of a transmission according to a third embodiment of the present invention. Explanation of code]
10: Transmission 12, 60, 70 ... Grease sealing structure of transmission 18: External gear (transmission mechanism)
20 ... Carrier member (transmission mechanism)
22 Internal gear (transmission mechanism)
24 ... casing 32 ... bearing 32A ... empty space 34 ... inner ring 36 ... outer ring 38 ... rolling element 40 ... oil seals 42, 62, 72 ... shield members 44, 62A, 72A ... partition wall 46 ... cylindrical part 62B ... rubber member 72B ... Inner cylindrical part 72C ... Outer cylindrical part

Claims (8)

A transmission mechanism, a casing for housing grease for lubricating the transmission mechanism, an oil seal for sealing the grease in the casing, an inner ring, an outer ring, and a rolling element; A bearing that rotatably supports the transmission mechanism in the vicinity of a seal, and a grease sealing structure for a transmission,
As the bearing, a bearing having an empty space in which one of the inner ring and the outer ring projects toward the oil seal side from the other is provided, and the grease between a rolling element of the bearing and the oil seal is provided. A grease sealing structure for a transmission, wherein a shield-like member for regulating movement of the bearing is provided in an empty space of the bearing. In claim 1,
The shield-shaped member is attached to the other of the outer ring and the inner ring of the bearing so that the shield-shaped member rotates relatively close to a member connected to one of the outer ring and the inner ring of the bearing and forms a labyrinth. A grease sealing structure for a transmission. In claim 1,
The transmission is characterized in that the shield-shaped member is attached to the other of the outer ring and the inner ring of the bearing so that the shield-shaped member rotates relatively to the member connected to one of the outer ring and the inner ring of the bearing. Grease sealing structure of machine. In claim 3,
The grease sealing structure of a transmission, wherein the sliding portion of the shield member is formed of a rubber member. In claim 1,
A grease sealing structure for a transmission, wherein the shield-like member is attached to the casing. In any one of claims 1 to 5,
The shield-like member includes a ring plate-shaped partition for separating the rolling element of the bearing and the oil seal, and a cylindrical portion that protrudes in an axial direction from one of an inner circumference and an outer circumference of the partition. A grease sealing structure for a transmission, comprising a ring having an L-shaped cross section. In any one of claims 1 to 5,
The shield-shaped member, a ring plate-shaped partition portion for separating the rolling element of the bearing and the oil seal, an inner cylindrical portion protruding from the inner periphery of the partition portion to the rolling element side in the axial direction, A grease sealing structure for a transmission, comprising: an annular body having a U-shaped cross section having an outer cylindrical portion protruding from the outer periphery of the partition wall portion toward the rolling element in the axial direction. In any one of claims 1 to 6,
A grease sealing structure for a transmission, wherein the grease is sealed as a first grease, and a second grease is sealed between the shield member and the oil seal.

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