JP2020190327A - Bearing device - Google Patents

Abstract

To provide a bearing device capable of preventing abrasion wear and seizure of a sliding portion between a cage and a planetary gear, a rolling portion between a roller and a planetary shaft, and a rolling portion between the roller and the planetary gear.SOLUTION: A bearing device 10 includes a needle roller bearing 20 disposed in a planetary gear 1, and a planetary shaft 30 inserted into the needle roller bearing 20. The planetary shaft 30 has an oil hole 31 for supplying a lubricant to the needle roller bearing 20, and an oil retaining hole 34 communicated to the oil hole 31, and is provided with an oil retaining material 40 for retaining the lubricant in the oil retaining hole 34.SELECTED DRAWING: Figure 1

Description

The present invention relates to a bearing device, for example, a bearing device that rotatably supports a planetary gear.

Conventionally, in planetary mechanisms widely used in transmissions and the like, needle roller bearings are used to rotatably support planetary gears. Further, as the needle roller bearing, for the purpose of preventing wear and seizure in a high-speed rotation and a dilute lubrication environment, at least the outer peripheral surface of the cage is provided with phosphate, a soft metal-based solid lubricant, and a layered crystal structure substance. It is known to form a composite film containing a solid lubricant selected from the above, or a composite film containing a phosphate and a phosphoric acid compound containing a soft metal (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2015-083861

However, in the needle roller bearing described in Patent Document 1, although the film formed on the cage can prevent wear and seizure of the sliding portion between the cage and the planetary gear, the roller and the planeter It was not possible to prevent wear and seizure of the rolling portion between the reshafting and the rolling portion between the roller and the planetary gear.

Furthermore, in such needle roller bearings, lubricating oil is supplied to the bearings by a lubricating oil pump, but in recent years, a mechanism that stops the lubricating oil pump when the engine is stopped, such as the transmission of some hybrid vehicles, has been used. It has appeared, and countermeasures against the seizure problem of bearings are required. In addition, when the vehicle is towed, the lubricating oil pump does not operate and the tires spin, which may cause seizure of the bearings in the transmission. Therefore, there has been a demand for a bearing device capable of preventing seizure even in a lubricating environment of a small amount of lubricating oil.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a cage even if a small amount of lubricating oil is lubricated or the supply of lubricating oil is temporarily stopped. It is an object of the present invention to provide a bearing device capable of preventing wear and seizure of a sliding portion between a planetary gear, a rolling portion between a roller and a planetary shaft, and a rolling portion between a roller and the planetary gear.

The above object of the present invention is achieved by the following configuration.
(1) A bearing device including a needle roller bearing arranged in a housing and a planetary shaft inserted into the needle roller bearing. The planetary shaft is a lubricating oil for the needle roller bearing. A bearing device having an oil hole for supplying oil and an oil retaining hole communicating with the oil hole, and an oil retaining material for holding lubricating oil is provided in the oil retaining hole.
(2) The bearing device according to (1), wherein the oil-retaining material constitutes a stopper for the oil hole.
(3) The bearing device according to (1), wherein the oil retaining material is fixed to the planetary shaft by press fitting or a stop ring into the oil retaining hole.
(4) The bearing device according to (1), wherein the oil-retaining material is provided not only in the oil-retaining hole but also in a part of the oil-retaining hole.
(5) The bearing device according to any one of (1) to (4), wherein the oil retaining material is a fiber material or a porous material.

According to the present invention, the planetary shaft has an oil hole for supplying lubricating oil to the needle roller bearing and an oil retaining hole for communicating with the oil hole, and is an oil retaining material for holding the lubricating oil in the oil retaining hole. When the amount of lubricating oil in the oil hole becomes very small, the lubricating oil stored in the oil-retaining material is supplied from the oil-retaining hole to the needle-shaped rollers. Therefore, even in a lubricating environment with a small amount of lubricating oil or when the supply of lubricating oil is temporarily stopped, the sliding part between the cage and the planetary gear, and between the needle roller and the planetary shaft It is possible to prevent wear and seizure of the rolling portion and the rolling portion between the needle-shaped roller and the planetary gear.

It is an enlarged sectional view explaining the planetary gear support part of the planetary mechanism to which the 1st Embodiment of the bearing apparatus which concerns on this invention is applied. It is an enlarged sectional view explaining the 1st modification of the bearing apparatus of 1st Embodiment. It is an enlarged sectional view explaining the 2nd modification of the bearing device of 1st Embodiment. It is an enlarged sectional view explaining the modification of the stop ring shown in FIG. It is an enlarged sectional view explaining the 3rd modification of the bearing device of 1st Embodiment. It is an enlarged sectional view explaining the 4th modification of the bearing device of 1st Embodiment. It is an enlarged sectional view explaining the 5th modification of the bearing apparatus of 1st Embodiment. It is an enlarged cross-sectional view explaining the modification of the stop ring shown in FIG. 7. It is an enlarged sectional view explaining the 6th modification of the bearing device of 1st Embodiment. It is an enlarged sectional view explaining the 7th modification of the bearing apparatus of 1st Embodiment. It is an enlarged sectional view explaining the 8th modification of the bearing apparatus of 1st Embodiment. It is an enlarged sectional view explaining the 2nd Embodiment of the bearing apparatus which concerns on this invention. It is an enlarged cross-sectional view explaining the 1st modification of the bearing apparatus of 2nd Embodiment. It is an enlarged cross-sectional view explaining the modification of the stop ring shown in FIG. It is an enlarged sectional view explaining the 2nd modification of the bearing apparatus of 2nd Embodiment. It is an enlarged sectional view explaining the 3rd modification of the bearing apparatus of 2nd Embodiment. It is an enlarged cross-sectional view explaining the modification of the oil-retaining material shown in FIG. It is an enlarged sectional view explaining the 3rd Embodiment of the bearing apparatus which concerns on this invention. It is an enlarged sectional view explaining the modification of the bearing apparatus of 3rd Embodiment.

Hereinafter, each embodiment of the bearing device according to the present invention will be described in detail with reference to the drawings. The arrows in each figure indicate the flow of lubricating oil.

(First Embodiment)
First, a first embodiment of the bearing device according to the present invention will be described with reference to FIGS. 1 to 11. In the following description, the radial direction and the circumferential direction are the radial direction and the circumferential direction of the planetary gear.

As shown in FIG. 1, the bearing device 10 of the present embodiment is applied to the planetary gear support portion of the planetary mechanism, and has a needle roller bearing 20 arranged in a cylindrical planetary gear (housing) 1 and a needle shape. A planetary shaft 30 that is inserted into a roller bearing 20 and whose both ends are fixed to a pair of carriers 2 is provided. As a result, the planetary gear 1 is rotatably supported by the planetary shaft 30 via the needle roller bearing 20. In this embodiment, the needle roller bearings 20 are in a row. Further, reference numeral 3 in FIG. 1 is a sun gear that meshes with the planetary gear 1.

The needle roller bearing 20 is a cage and roller type, and surrounds a plurality of needle rollers 21 that roll between the outer peripheral surface of the planetary shaft 30 and the inner peripheral surface of the planetary gear 1 and a plurality of needle rollers 21. A cage 22 for holding the cages in the directions at substantially equal intervals is provided. The needle roller bearing 20 receives a radial load acting on the planetary gear 1. Further, the cage 22 is guided by the inner peripheral surface of the planetary gear 1.

The planetary shaft 30 has an oil hole 31 for supplying lubricating oil to the needle roller bearing 20, and an oil retention hole 34 communicating with the oil hole 31.

The oil holes 31 include an axial oil hole 32 formed along the axial direction at the axial center of the planetary shaft 30, a radial oil hole 33 extending radially outward from the axial inner end of the axial oil hole 32, and the like. Has. The axial oil hole 32 is formed from one end (right end in FIG. 1) to the other end (left end in FIG. 1) of the planetary shaft 30 and penetrates one end side of the planetary shaft 30. The radial inner end of the radial oil hole 33 opens in the axial oil hole 32, and the radial outer end thereof opens in the outer peripheral surface of the planetary shaft 30. The oil retention hole 34 is continuously formed from the other end of the axial oil hole 32 toward the other end side, and does not penetrate the other end side of the planetary shaft 30.

Further, on one end side (right end side in FIG. 1) of the planetary shaft 30, an oil receiver 4 for receiving lubricating oil in a transmission or the like in which a planetary mechanism is incorporated is arranged. As a result, the lubricating oil that has entered the oil receiver 4 is supplied to the needle-shaped roller 21 via the axial oil hole 32 and the radial oil hole 33. Therefore, the bearing device 10 of the present embodiment has a structure in which the oil receiver 4 receives and supplies the lubricating oil bounced up by a rotating member such as a gear or the lubricating oil supplied by the lubricating oil pump or the like and discharged from the input shaft. Is.

An oil retaining material 40 for holding the lubricating oil is provided in the oil retaining hole 34. In the present embodiment, the oil retaining material 40 is arranged on the side opposite to the lubricating oil inflow side with respect to the radial oil hole 33, that is, on the other end side (left end side in FIG. 1) of the planetary shaft 30.

The oil-retaining material 40 is a member capable of holding lubricating oil by a capillary phenomenon, stores the lubricating oil inside, and supplies the stored lubricating oil to the radial oil hole 33. The material of the oil-retaining material 40 may be any material that causes a capillary phenomenon. For example, a fiber material made of a non-woven fabric such as polyester felt, a foamed resin or foam rubber, or a porous material such as a sintered metal or foamed ceramics. Can be mentioned.

Here, the material of the oil-retaining material will be described. The oil-retaining material is preferably one that easily absorbs lubricating oil. This can utilize the principle of capillarity (surface tension) that occurs when the oil-retaining material is lipophilic (not oil-repellent) and is separated by a minute space. As a result, the lubricating oil that comes into contact with the oil-retaining material is quickly sucked into the oil-retaining material.

For example, a material hardened with resin while securing pores with an aggregate of fibers having lipophilicity (not oil repellent) can be fixed to a shaft to exert an oil-retaining function (fibers are entwined). Since there is a possibility that the durability of the non-woven fabric is low, it is preferable to impregnate the non-woven fabric with resin to some extent to increase the binding strength of the fibers). The same effect can be achieved if the material is a fiber having lipophilicity (not oil repellent) regardless of whether it is organic or inorganic. However, in order to retain oil, a pore portion for storing lubricating oil is required, and the higher the porosity, the higher the amount of oil retained in the same volume of the oil retaining material. Therefore, a porosity of about 20% to 90% is suitable.

Further, it is also possible to use a porous material instead of a fiber as the oil retaining material. This can be manufactured, for example, by insert molding a lipophilic (not oil-repellent) foamed resin, foamed rubber, or the like into the core metal without performing a separate bonding step. In addition, since it is necessary to allow the lubricating oil to permeate, this foamed resin or foamed rubber has through pores and is formed in a state where the bubbles are connected without being separated by the diaphragm, and the lubricating oil can freely flow in the oil retaining material. Allow it to penetrate. Since finer pore bubbles are more advantageous for surface tension, the bubble diameter is preferably about 0.005 mm to 0.5 mm. In addition, since this foamed resin or foamed rubber also utilizes the adsorption of lubricating oil by surface tension, it is necessary to select a material with lipophilicity (not oil repellent), but organic and inorganic materials are not particularly limited. .. The manufacturing method described here is a general technique that is widely used, and mass production can be easily realized at low cost.

Further, when exposed to a harsh usage environment such as high heat resistance and chemical resistance, a porous material such as a sintered metal or foamed ceramic can be used as an oil retaining material.

In the bearing device 10 configured in this way, when the lubricating oil is supplied to the axial oil hole 32 from the outside (oil receiver 4), the lubricating oil that has passed through the axial oil hole 32 is supplied from the radial oil hole 33. Along with being supplied to the needle-shaped roller 21, the lubricating oil abundantly present in the axial oil hole 32 is stored in the oil retaining material 40 of the oil retaining hole 34. On the other hand, when the lubricating oil is not supplied to the axial oil hole 32 and the amount of the lubricating oil in the axial oil hole 32 becomes small, the lubricating oil stored in the oil retaining material 40 is needle-shaped from the radial oil hole 33. It is supplied to the roller 21.

As described above, according to the bearing device 10 of the present embodiment, since the oil-retaining material 40 for holding the lubricating oil is provided in the oil-retaining hole 34 of the planetary shaft 30, the lubricating oil in the axial oil hole 32 is released. When the amount becomes small, the lubricating oil stored in the oil-retaining material 40 is supplied to the needle-shaped roller 21 from the oil-retaining hole 34. Therefore, even if the lubricating environment is a small amount of lubricating oil or the supply of lubricating oil is temporarily stopped, the sliding portion between the cage 22 and the planetary gear 1, the needle roller 21 and the planetary shaft It is possible to prevent wear and seizure of the rolling portion between the 30 and the rolling portion between the needle roller 21 and the planetary gear 1.

Further, according to the bearing device 10 of the present embodiment, it is not necessary to supply more lubricating oil to the bearing device 10 in order to prevent seizure, and the amount of lubricating oil can be significantly reduced. Stirring resistance can be reduced, and it can also be effective for lubrication at the time of starting at an extremely low temperature.

Further, according to the bearing device 10 of the present embodiment, even if the lubricating oil is intermittently supplied into the bearing device or the lubricating oil in the bearing device is in a trace amount, wear or wear occurs. It is possible to prevent seizure and maintain bearing performance and lubrication effect for a long period of time. Therefore, the bearing device 10 of the present embodiment can be suitably used for a mechanism in which the lubricating oil pump is temporarily stopped when the engine is stopped, such as a transmission of some hybrid vehicles, and is also a bearing of an automobile. It is possible to deal with situations where it is difficult to supply sufficient lubricating oil because the lubricating oil pump does not operate during traction.

As a first modification of the present embodiment, as shown in FIG. 2, the oil retaining material 40 may be provided in the entire area of the axial oil hole 32 and the oil retaining hole 34. As a result, the amount of lubricating oil supplied to the needle-shaped roller 21 can be controlled by the oil-retaining material 40, and the stirring resistance of the lubricating oil can be further reduced. The oil-retaining material 40 is preferably made of a material having good oil permeability so that the minimum necessary lubricating oil can pass through.

Further, as a second modification of the present embodiment, as shown in FIG. 3, the oil retaining material 40 may be fixed to the oil retaining hole 34 by a retaining ring 50. Thereby, it is possible to prevent the oil-retaining material 40 from coming off. Further, as shown in FIG. 4, the axial width of the stop ring 50 may be larger than that in FIG. The axial width dimension of the stop ring 50 is regulated to 50 to 90% of the axial width dimension (hole diameter) of the radial oil hole 33. By setting it to 50% or more, it is possible to prevent the stop ring 50 from coming off. By setting it to 90% or less, even if the stop ring 50 moves to one end side in the axial direction (right side in FIG. 4), the stop ring 50 prevents the stop ring 50 from completely closing the radial oil hole 33.

Further, the oil retaining material 40 may be integrated with the retaining ring 50 by fitting or insert molding. In this case, the oil-retaining material 40 can be fixed to the oil-retaining hole 34 by press-fitting the stop ring 50, so that the productivity can be improved.

Further, as a third modification of the present embodiment, as shown in FIG. 5, a plurality of types (two types in this modification) of oil-retaining material 40 may be provided in the axial oil hole 32 and the oil-retaining hole 34. Good. In this case, the oil-retaining material 40 arranged in the axial oil hole 32 on the upstream side (right side in FIG. 5) of the oil supply path with respect to the radial oil hole 33 is passed so that the minimum necessary lubricating oil can pass through. It is preferable to use a material with good oiliness.

Further, as a fourth modification of the present embodiment, as shown in FIG. 6, an oil retaining hole 34 is formed in a through hole penetrating in the axial direction, and the oil retaining material 40 is press-fitted into the penetrating oil retaining hole 34. It may be fixed. According to this modification, since the oil retention hole 34 is a through hole, the workability of the planetary shaft 30 can be improved. Further, the metal powder at the time of hole processing can be easily removed from the oil hole.

Further, as a fifth modification of the present embodiment, as shown in FIG. 7, the oil retention hole 34 is formed in a through hole penetrating in the axial direction, and the oil retention material 40 is fixed to the penetrating oil retention hole 34. It may be fixed by 50. Further, as shown in FIG. 8, the axial width of the stop ring 50 may be larger than that in FIG. 7.

Further, as a sixth modification of the present embodiment, as shown in FIG. 9, the axial oil hole 32 and the oil retention hole 34 may be formed to have different inner diameters from each other. Specifically, the axial oil hole 32 is formed to have a larger diameter than the oil retention hole 34. In this case, a step portion 32a is formed at the boundary portion between the axial oil hole 32 and the oil retention hole 34. The inner peripheral surface of the step portion 32a is formed as an inclined surface whose diameter increases toward the upstream side of the refueling path. As a result, the lubricating oil discharged from the oil-retaining material 40 can be guided to the radial oil hole 33 by utilizing the centrifugal force acting on the planetary shaft 30 revolving around the central axis of the planetary mechanism (sun gear 3). The efficiency of refueling the needle roller 21 can be improved.

Further, as a seventh modification of the present embodiment, as shown in FIG. 10, the radial oil hole 33 may be formed so as to be inclined with respect to the radial direction of the planetary shaft 30. In this case, the inclination direction of the radial oil hole 33 is a direction in which the intersection angle between the oil retention hole 34 and the radial oil hole 33 is obtuse. According to this modification, the lubricating oil discharged from the oil retaining material 40 is guided to the radial oil hole 33 by utilizing the centrifugal force acting on the planetary shaft 30 revolving around the central axis of the planetary mechanism (sun gear 3). This makes it possible to improve the efficiency of refueling the needle roller 21.

Further, as an eighth modification of the present embodiment, as shown in FIG. 11, the oil retention hole 34 may be formed so as to extend radially outward from the axial oil hole 32, similarly to the radial oil hole 33. Good. In this modification, the oil retention holes 34 are formed on both sides in the axial direction with the radial oil holes 33 interposed therebetween. According to this modification, the lubricating oil stored in the oil-retaining material 40 can be directly supplied to the needle-shaped roller 21 from the oil-retaining hole 34.

(Second Embodiment)
Next, a second embodiment of the bearing device according to the present invention will be described with reference to FIGS. 12 to 17. The same or equivalent parts as those in the first embodiment are designated by the same reference numerals in the drawings, and the description thereof will be omitted or simplified.

In the present embodiment, as shown in FIG. 12, the planetary shaft 30 has an oil hole 35 for supplying lubricating oil to the needle roller bearing 20, and an oil retention hole 39 communicating with the oil hole 35.

The oil holes 35 are an axial oil hole 36 formed along the axial direction at the axial center of the planetary shaft 30, and a first radial oil hole 37 extending radially outward from the axial inner end of the axial oil hole 36. And a second radial oil hole 38 extending radially outward from the axial outer end (right end in FIG. 12) of the axial oil hole 36. The axial oil hole 36 is formed from the axial center of the planetary shaft 30 toward one end (right end in FIG. 12), and does not penetrate one end side. The radial inner end of the first radial oil hole 37 and the second radial oil hole 38 opens in the axial oil hole 36, and the radial outer end thereof opens in the outer peripheral surface of the planetary shaft 30. The first radial oil hole 37 is a hole through which the lubricating oil flows out, and the second radial oil hole 38 is a hole through which the lubricating oil flows. The oil retention hole 39 is formed at the same time as the axial oil hole 36, and penetrates the other end side of the planetary shaft 30.

Further, an oil passage 2a formed in the carrier 2 on one side (right side in FIG. 12) is connected to the second radial oil hole 38, and the oil passage 2a is connected to the second radial oil hole 38. Lubricating oil is being supplied. As a result, the lubricating oil supplied from the oil passage 2a to the second radial oil hole 38 is supplied to the needle roller 21 through the axial oil hole 36 and the first radial oil hole 37. Therefore, the bearing device 10 of the present embodiment has a structure in which lubricating oil is pumped and supplied by a lubricating oil pump or the like (not shown).

An oil retaining material 40 for holding the lubricating oil is provided in the oil retaining hole 39. In the present embodiment, the oil retaining material 40 is arranged on the side opposite to the lubricating oil inflow side with respect to the first radial oil hole 37, that is, on the other end side (left end side in FIG. 12) of the planetary shaft 30. .. Further, the oil retaining material 40 is fixed to the oil retaining hole 39 by press fitting, and constitutes a stopcock for the axial oil hole 36.

In the bearing device 10 configured in this way, when the lubricating oil is supplied to the axial oil hole 36, the lubricating oil that has passed through the axial oil hole 36 is transferred from the first radial oil hole 37 to the needle roller 21. At the same time as being supplied, the lubricating oil abundantly present in the axial oil hole 36 is stored in the oil retaining material 40 of the oil retaining hole 39. On the other hand, when the lubricating oil is not supplied to the axial oil hole 36 and the amount of the lubricating oil in the axial oil hole 36 becomes small, the lubricating oil stored in the oil retaining material 40 is discharged from the first radial oil hole 37. It is supplied to the needle roller 21. As a result, the amount of lubricating oil can be reduced, so that the capacity of the lubricating oil pump can be reduced.

As described above, according to the bearing device 10 of the present embodiment, since the oil-retaining material 40 for holding the lubricating oil is provided in the oil-retaining hole 39 of the planetary shaft 30, the lubricating oil in the axial oil hole 36 is released. When the amount becomes very small, the lubricating oil stored in the oil-retaining material 40 is supplied to the needle-shaped roller 21 from the first radial oil hole 37. Therefore, even if the lubricating environment is a small amount of lubricating oil or the supply of lubricating oil is temporarily stopped, the sliding portion between the cage 22 and the planetary gear 1, the needle roller 21 and the planetary shaft It is possible to prevent wear and seizure of the rolling portion between the 30 and the rolling portion between the needle roller 21 and the planetary gear 1.

Further, as a first modification of the present embodiment, as shown in FIG. 13, the oil retaining material 40 may be fixed to the oil retaining hole 39 by a retaining ring 50. Further, as shown in FIG. 14, the axial width of the stop ring 50 may be larger than that in FIG.

Further, as a second modification of the present embodiment, as shown in FIG. 15, the oil retaining material 40 may be fixed to the oil retaining hole 39 by a stopcock 51. In this case, the oil-retaining material 40 is integrated with the stopcock 51 by adhesion, fitting, or insert molding, and is fixed to the oil-retaining hole 39 by press-fitting the stopcock 51. Therefore, since only the stopcock 51 needs to be press-fitted, there is no change in the conventional assembly process, and the assembling property can be improved.

Further, as a third modification of the present embodiment, as shown in FIG. 16, in the modification of FIG. 15, the planetary shaft 30, the axial oil hole 36, and the oil retention hole 39 are made larger in diameter than in FIG. You may. Further, as shown in FIG. 17, a hollow cylindrical oil retaining material 40 may be fixed to the inner peripheral surface of the oil retaining hole 39 having a large diameter.
Other configurations and effects are the same as those in the first embodiment.

(Third Embodiment)
Next, a third embodiment of the bearing device according to the present invention will be described with reference to FIGS. 18 and 19. The same or equivalent parts as those in the first and second embodiments are designated by the same reference numerals in the drawings, and the description thereof will be omitted or simplified.

In this embodiment, as shown in FIG. 18, two rows of needle roller bearings 20 are arranged between the planetary gear 1 and the planetary shaft 30. As shown in FIG. 19, spacers 25 may be arranged between the two rows of needle roller bearings 20.
Other configurations and effects are the same as those in the first and second embodiments.

Here, a lubrication environment in which the amount of lubricating oil in the present specification is very small will be described. For example, in the case of a transmission such as an automobile, there are generally two known methods for supplying lubricating oil: splashing of lubricating oil by a rotating member such as a gear, and pumping of lubricating oil by a lubricating oil pump.

In the above two structures, in order to prevent seizure of the bearing, an amount of lubricating oil of about 50 cc / min to 1000 cc / min is supplied. If the amount of the lubricating oil is less than 10 cc / min, heat generation and seizure are likely to occur due to insufficient oil film due to the lack of lubricating oil, and seizure occurs at 0 cc / min (non-lubricated oil). The present invention corresponds to a dilute lubricated state rather than a non-lubricated state, and has a great effect in a lubricating environment where a small amount of lubricating oil is used, specifically, in a dilute lubricated state of about 0.01 cc / min to 10 cc / min. Demonstrate.

Next, the environment in which the lubricating oil in the present specification is intermittently supplied will be described. For example, in a hybrid vehicle, there is a mode in which the vehicle runs on an electric motor with the engine stopped. In this mode, in the structure of only the lubricating oil pump directly connected to the engine, the running is performed in a state where the lubricating oil is not supplied to the bearings. For this reason, a non-lubricated running state occurs for up to several minutes, but the bearing must not seize during this period. There is a need to extend this electric running time with the evolution of batteries. At present, in order to prevent seizure, some vehicle models are controlled to operate the lubricating oil pump by rotating the engine at regular intervals. In order to solve this problem, it is necessary to add an electric lubricating oil pump to the system or to adopt a non-lubricating and seizure-resistant bearing device as in the present invention. In the present invention, since the time until seizure is related to the amount of oil retained in the oil-retaining material, the non-lubrication application time can be significantly extended from several tens of minutes to several hours by increasing the amount of oil retained. Is possible. The increase in the amount of oil retention can be dealt with, for example, by increasing the porosity or the volume of the oil retention material.

In addition, a passenger car may be towed as an auxiliary vehicle in the event of a breakdown or at a destination of a large vehicle such as a camper. In such a case, it is possible to prevent idling by mounting the drive wheels of the vehicle on a trolley or the like, but in reality, there are cases where the drive wheels are towed while idling. Then, in this idling state, the engine and the electric lubricating oil pump do not operate, and the lubricating oil pump is stopped, so that the bearing is liable to seize. As a countermeasure for this, some models have devised a drive device so that splash refueling occurs. In the present invention, even if the lubricating oil pump is stopped, the bearings can be refueled until the lubricating oil stored in the oil-retaining material is exhausted. Therefore, seizure resistance occurs even in a towed state where there is insufficient or no splashing. The sex can be greatly improved.

The present invention is not limited to those exemplified in each of the above embodiments, and can be appropriately modified without departing from the gist of the present invention.
For example, the planetary shaft of each embodiment, one row of needle roller bearings (see FIGS. 1 to 17), two rows of needle roller bearings (see FIG. 18), and two rows of needle roller bearings with spacers. The combination with (see FIG. 19) is free.

1 Planetary gear (housing)
2 Carrier 2a Oil passage 3 Sun gear 4 Oil receiver 10 Bearing device 20 Needle roller bearing 21 Needle roller 22 Cage 30 Planetary shaft 31 Oil hole 32 Axial oil hole 33 Radial oil hole 34 Oil retention hole 35 Oil hole 36 Shaft Directional oil hole 37 1st radial oil hole 38 2nd radial direction oil hole 39 Oil retention hole 40 Oil retention material 50 Stop ring 51 Stop plug

Claims (5)

A bearing device including a needle roller bearing arranged in a housing and a planetary shaft inserted into the needle roller bearing.
The planetary shaft has an oil hole for supplying lubricating oil to the needle roller bearing and an oil retention hole communicating with the oil hole.
A bearing device characterized in that an oil-retaining material for holding lubricating oil is provided in the oil-retaining hole. The bearing device according to claim 1, wherein the oil-retaining material constitutes a stopcock for the oil hole. The bearing device according to claim 1, wherein the oil-retaining material is fixed to the planetary shaft by press-fitting or a retaining ring into the oil-retaining hole. The bearing device according to claim 1, wherein the oil-retaining material is provided not only in the oil-retaining hole but also in a part of the oil-retaining hole. The bearing device according to any one of claims 1 to 4, wherein the oil-retaining material is a fiber material or a porous material.

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