TWI651158B - Spindle device - Google Patents

Abstract

An object of the present invention is to provide a portion in which a sliding bearing member is placed in a main shaft of a lubricating oil so as not to cause heat generation and to prevent the lubricating oil from leaking out of the casing. The solution of the present invention is to provide a partition wall surrounded by an extension of a main shaft extending from the sliding bearing member, and having an opening defined with an annular gap between the outer circumference of the main shaft; Positioned on the side of the partition wall away from the sliding bearing member, and communicated with the annular gap to supply pressurized air; and the exhaust passage, between the sliding bearing member and the side of the partition wall of the sliding bearing member toward the housing assembly The outside is open.

Description

Spindle device Field of invention

The present invention relates to a spindle device, and more particularly to a spindle device that supports a spindle by a sliding bearing.

Background of the invention

For a spindle device used in a working machine, a spindle bearing is known by a sliding bearing called a metal bearing (for example, Patent Document 1). In the case of a plain bearing device, there is known a device in which a non-true circular sliding bearing member such as a Mackensen type bearing is used, between the inner circumference of the sliding bearing member and the outer circumference of the main shaft. In many cases in the circumferential direction, a wedge-shaped gap (pressure generating portion) is formed at three places separated by 120 degrees, and dynamic pressure generated by introducing lubricating oil (non-pressure viscous fluid) into the gap ( Oil film pressure) to support the rotating shaft (spindle) (for example, Patent Document 2).

Advanced technical literature Patent literature

Patent Document 1: Japanese Invention Patent Application Publication No. 2004-9180

Patent Document 2: Japanese Invention Patent Application Publication No. 2001-65548

Summary of invention

In the dynamic pressure type sliding bearing device, in order to obtain high concentric support precision, the entire arrangement portion of the sliding bearing member is immersed in the lubricating oil, and the pressure generating portions at several places are all under the same conditions by the lubricating oil. It is preferable that the pressure generating portions provided at a plurality of places around the circumference of the main shaft generate equal dynamic pressure with each other.

One end side of the main shaft extends from the sliding bearing member in the axial direction, and protrudes toward the outside of the casing through a through hole formed in the casing in which the main shaft and the sliding bearing member are housed. Therefore, it is necessary to prevent the arrangement portion of the sliding bearing member from being immersed. The lubricating oil leaks from the outer circumference of the main shaft and the inner circumference of the perforation to the outside of the casing. Although it is considered to prevent the leakage of the lubricating oil by a general contact type oil seal, heat is generated due to the rotational friction of the main shaft and the oil seal, resulting in a decrease in positional accuracy due to thermal expansion of the main shaft.

The object to be solved by the present invention is that the arrangement portion of the sliding bearing member is immersed in the main shaft of the lubricating oil, does not cause heat generation, and prevents the lubricating oil from leaking out of the casing.

The spindle device according to the present invention is a sliding bearing member (36) having a main shaft (24), a journal portion (24B) supporting the main shaft (24), and a housing for housing the main shaft (24) and the sliding bearing member (36) a body (12), and the aforementioned sliding bearing member (36) is immersed in a lubricating oil spindle device (10), and the spindle device comprises: a partition wall (18A) extending from the outer portion by the aforementioned sliding bearing member (36) Forming an extension (24E) of the aforementioned main shaft (24), and having an opening (46) defining an annular gap (48) between the outer circumference of the main shaft (24); an air passage (70), a side of the partition wall (18A) remote from the sliding bearing member (36), and communicating with the annular gap (48) to supply pressurized air; and an exhaust passage (74) for the sliding bearing member ( 36) is open to the outside of the casing (12) between the partition wall (18A).

With this configuration, the air passage (70) flows out of the annular space (48) and flows between the sliding bearing member (36) and the side of the partition wall (18A) of the sliding bearing member (36). Exhaust from the exhaust passage (74) to the outside of the casing (12), so that the back pressure does not rise, and the flow from the annular gap (48) to the sliding bearing member (36) and the partition wall (18A) The flow of the compressed air becomes sure, and it is surely prevented that the lubricating oil leaks to the outside from the side of the sliding bearing member (36) through the annular gap (48). Secondly, this form is carried out in a non-contact manner in which no rotational friction is generated, so that heat generation is not caused.

According to the spindle device of the present invention, preferably, the partition wall (18A) is partially formed by the casing (12), and the air passage (70) includes a radial passage (66) provided in the casing ( 12); and an annular passage (68) communicating with the radial passage (66) and surrounding the aforementioned main shaft (24) from the outside.

According to this configuration, the pressurized air flows out of the annular space (48) over the entire area, and the lubricating oil can be more reliably prevented from leaking to the outside through the annular space (48).

According to the spindle device of the present invention, it is preferable that a labyrinth seal (72) is formed on the side farther from the sliding bearing member (36) than the air passage (70).

According to this configuration, even if the lubricating oil leaks from the annular space (48) to the front side, the oil leakage can be prevented in a fail-safe state.

According to the spindle device of the present invention, preferably, between the sliding bearing member (36) and the side of the partition wall (18A) facing the sliding bearing member (36), a spindle (24) is defined. An expansion chamber (62) that expands radially outward on the outer peripheral side.

According to this configuration, the expansion chamber (62) becomes a space that expands from the annular space (48), so that the outflow of the pressurized air flowing from the annular space (48) to the expansion chamber (62) can be performed well, thereby avoiding The effect of the lubricating oil in the expansion chamber (62) leaking to the outside through the annular gap (48) is enhanced.

According to the spindle device of the present invention, it is preferable that an oil retaining ring (50) is attached to an end portion of the sliding bearing member (36) away from the partition wall (18A), and the oil retaining ring reduces the housing (12). a gap between the inner circumference and the outer circumference of the aforementioned main shaft (24), and one of the inner circumference of the casing (12) and the outer circumference of the main shaft (24) is in a non-contact state with respect to the other, and has the aforementioned oil retaining The ring (50) supplies a lubricating oil supply passage (52) to the side of the aforementioned sliding bearing member (36).

According to this configuration, the amount of oil of the lubricating oil filled in the casing (12) can be reduced by the arrangement of the oil retaining ring (50).

According to the spindle device of the present invention, the pressurized air flowing from the air passage to the annular gap and flowing between the sliding bearing member and the side facing the partition wall of the sliding bearing member can be discharged from the exhaust passage outside the casing, so The back pressure is increased to flow between the sliding bearing member and the partition wall via the annular gap The flow of the pressurized air becomes reliable, does not cause heat generation, and can reliably prevent the lubricating oil from leaking to the outside through the annular gap from the side of the sliding bearing member.

10‧‧‧ spindle device

12‧‧‧Shell assembly (housing)

14‧‧‧Front shell components

16‧‧‧ Rear housing components

18‧‧‧ front end components

18A‧‧‧ next door

20‧‧‧ Backend components

22‧‧‧Internal space

24‧‧‧ Spindle

24A‧‧‧ taper shank

24B‧‧‧Axial neck

24C‧‧‧Threaded shaft

24D‧‧‧Rounds

24E‧‧‧Exiting Department

24F‧‧‧ back end

26‧‧‧Sliding bearing unit

28‧‧‧Ball bearings

30‧‧‧ rolling bearing unit

32‧‧‧ bearing box

34‧‧‧Conical hole

36‧‧‧Sliding bearing components

36A‧‧‧ Thick Wall

36B‧‧‧ Thin wall

38‧‧‧ center hole

40‧‧‧ annular gap

42‧‧‧pressure ring

44‧‧‧ nuts

46‧‧‧ openings

48‧‧‧ annular gap

50‧‧‧ oil retaining ring

52‧‧‧ oil supply channel

54‧‧‧ recess

56‧‧‧ annular groove

58‧‧‧ oil road

60,62‧‧‧Expansion room

64‧‧‧ annular gap

66‧‧‧ Radial direction channel

68‧‧‧Ring channel

70‧‧‧Air passage

72‧‧‧ labyrinth ring

74‧‧‧Exhaust passage

75,76,78‧‧‧ Oil drain

80‧‧‧ openings

82‧‧‧ annular gap

84‧‧‧Air passage

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a longitudinal cross-sectional view showing an embodiment of a spindle device of the present invention.

Fig. 2 is an enlarged longitudinal cross-sectional view showing the main part of the spindle unit of the embodiment.

Figure 3 is a cross-sectional view taken along line III-III of Figure 2;

Detailed description of the preferred embodiment

Hereinafter, an embodiment of a spindle device according to the present invention will be described with reference to Figs. 1 to 3 .

The spindle device 10 has a cylindrical casing assembly 12. The housing assembly 12 has a coupling body of the front housing member 14 and the rear housing member 16, a front end member 18 fixed to the front end of the front housing member 14, and a rear end end fixed to the rear housing member 16. Member 20. The members are integrally formed by bolts (not shown) and define an inner space 22 having a circular transverse cross section extending in the axial direction.

The inner space 22 is provided with a main shaft 24 having a circular transverse cross section. The main shaft 24 extends in the longitudinal direction of the inner space 22 on the central axis of the inner space 22, so that the front portion is rotatably supported by the sliding bearing device 26, and the rolling bearing device 30 having the rear portion formed by the four rows of ball bearings 28 is Rotatingly supported. Spindle The front end of the 24 is extended forward by the front end member 18, and the extended portion is formed as a taper shank portion 24A to which a holder or the like is attached.

The plain bearing device 26 has a bearing housing 32 that is inserted into the front side of the inner space 22 and that is fixed to the front housing member 14. The bearing housing 32 has a tapered bore 34 that is smaller in diameter toward the rear. The tapered bore 34 has a sliding bearing member 36 inserted therein.

The sliding bearing member 36 is made of a metal such as a white metal, as shown in FIG. 3, and is a non-true round shape of a bearing called a Mackensen type bearing having a center hole 38 through which the main shaft 24 passes. A thick-walled portion 36A formed in three circumferential directions (equal intervals of 180 degrees) and fitted to the tapered hole 34; and a thin-walled portion 36B that connects the adjacent thick-walled portions 36A to each other. The main shaft 24 is a journal portion 24B formed by forming a portion penetrating through the center hole 38 as a straight shaft portion that is rotatably supported by the sliding bearing member 36. An annular gap 40 constituting the oil film is formed between the outer peripheral surface of the journal portion 24B and the inner peripheral surface of the center hole 38.

The sliding bearing member 36 presses the small diameter side of the tapered hole 34 by the spiral engagement of the pressure-resistant ring 42 of the bearing housing 32, whereby the tapered portion 34 and the tapered hole 34 form a tapered engagement (wedge) The thin portion 36B is elastically deformed toward the radially outer side. By this elastic deformation, the annular gap 40 is deformed into a circumferentially extending wedge shape in each thick portion 36A, and the wedge-shaped portion becomes a pressure generating portion of the oil film.

The main shaft 24 is formed to extend forward from the sliding bearing member 36. The extended portion is sequentially formed as a threaded shaft portion 24C and a ring-shaped projecting portion 24D from the side of the journal portion 24B as shown in FIG. The extended portion 24E formed by the straight shaft portion and the tapered handle portion 24A described above. The threaded shaft portion 24C has a nut 44 Spiral snap fit.

The front end member 18 forms an end wall on the front side of the casing assembly 12, and the extension portion 24E passes through the opening 46 formed in the circular cross-sectional shape formed at the center portion to form a partition wall from the outer circumference extending portion 24E. An annular gap 48 is defined between the outer peripheral surface of the outlet portion 24E and the inner peripheral surface of the opening 46. The annular space 48 is a minute gap, whereby the front end member 18 is formed into a non-contact metal seal (oil retaining portion).

In the present embodiment, as shown in the reference numeral 18A in Fig. 2, the front end member 18 is directed from the annular passage 68, which will be described later, toward the sliding bearing member 36 side. Part of it.

An oil retaining ring 50 is fixed to the rear end portion of the front housing member 14 at a rear side of the relatively sliding bearing member 36 (away from the end side of the front end member 18 (partition wall)) (refer to FIG. 1). The slinger 50 functions to reduce the gap between the inner circumference of the front housing member 14 and the outer circumference of the main shaft 24 in a non-contact manner with respect to the outer peripheral surface of the main shaft 24 as an oil dam. .

An oil supply passage (lubricating oil supply passage) 52 is formed in the front housing member 14. The oil supply passage 52 is communicated with the inner space 22 which is closer to the side of the sliding bearing member 36 than the oil retaining ring 50. A lubricating oil (viscous non-compressible fluid) pressurized externally is supplied to the oil supply passage 52, and the lubricating oil is filled into the casing assembly 12, and the inner end space 22 is filled with a metal seal before the end member is formed. The entire space between the 18 and the slinger 50 including the annular gap 40 is included. By the presence of the oil retaining ring 50, the amount of oil of the lubricating oil filled in the casing assembly 12 can be reduced.

In addition, in the form of the spindle device 10 arranged horizontally, the lubricating oil It is not necessary to fill the inside of the casing assembly 12 and fill the entire space of the inner space 22 to form a space between the end member 18 and the slinger 50 before the metal sealing, as long as the entire annular gap 40 can be immersed in the lubricating oil. Fill in the amount of lubricating oil. At this time, the expansion chamber 62 to be described later is an oil groove having a lubricating oil composed of a liquid amount in which the entire annular gap 40 is soaked by the lubricating oil.

The supply of the lubricating oil from the oil supply passage 52 to the annular gap 40 is formed by the annular groove 56 formed in the outer peripheral portion of the bearing housing 32 via the recess 54 formed in the inner peripheral portion of the front housing member 14. The oil passage 58 in the bearing housing 32, the path of the expansion chamber 60 on the rear side of the bearing cartridge 32, and the path of the outer peripheral surface of the expansion chamber 62 and the journal portion 24B on the front side of the bearing cartridge 32 are branched by the oil passage 58. get on. The supply of the lubricating oil from the oil supply passage 52 to the expansion chamber 62 is also performed by the annular gap 64 formed between the inner circumferential surface of the front housing member 14 and the outer circumferential surface of the bearing housing 32. Further, the expansion chamber 62 is an expansion chamber that expands the axial direction portion between the sliding bearing member 36 and the front end member 18 (the side facing the partition wall of the sliding bearing member 36) radially outward from the sliding bearing member 36, as described above. It has a volume that forms an oil sump and is useful for gas-liquid separation.

An air passage 70 is formed in the front end member 18, and the air passage 70 is formed by a radial passage 66 and an annular passage 68 that communicates with the radial passage 66 from the outer circumferential portion 24E. The air passage 70 is defined on the side (front side) of the partition wall 18A away from the sliding bearing member 36, communicates with the annular gap 48, and is supplied with pressurized air from the outside.

In the side (front side) farther from the sliding bearing member 36 than the open passage 70, the gap between the end member 18 and the extension portion 24E constitutes a gas seal (air A labyrinth seal 72 of the seal type is formed by a portion of the pressurized air supplied to the annular passage 68.

An exhaust passage 74 is formed in the front end member 18 between the sliding bearing member 36 and the side of the partition wall 18A facing the sliding bearing member 36, that is, the upper portion of the expansion chamber 62 toward the housing assembly 12. The outside is open, that is, the atmosphere is open.

As shown in FIG. 1, the rear casing member 16 and the rear end member 20 are formed with oil discharge passages 75, 76 for discharging lubricating oil leaking from the gap of the slinger 50 toward the rear side to the outside of the casing assembly 12. . The oil discharge passage 78 is formed in the rear end member 20 to discharge the lubricating oil leaking toward the rear side by the rolling bearing device 30 to the outside of the casing assembly 12.

The rear end portion 24F of the main shaft 24 is formed to extend through the opening 80 formed in the circular cross section of the rear end member 20, and extends rearward from the rear end member 20. In the rear end member 20, an air passage 84 that supplies pressurized air to the annular space 82 between the inner circumferential surface of the opening 80 and the outer circumferential surface of the rear end portion 24F to form a non-contact air seal is formed.

The oil supply passage oil 52 is supplied to the casing assembly 12, in other words, the amount of oil supplied to the lubricating oil of the sliding bearing device 26 is naturally discharged to the casing by the exhaust passage 74 and the oil discharge passages 75, 76, 78. The amount of oil outside the assembled body 12 is large, and the annular gap 40 between the journal portion 24B and the sliding bearing member 36 is always filled with lubricating oil, and an oil film is formed in the annular gap 40.

When the main shaft 24 rotates, the annular gap 40 corresponds to a portion of each of the thick wall portions 36A of the sliding bearing member 36 which is deformed into a wedge shape. The rotation of the main shaft 24 is introduced, and dynamic pressure is generated in the deformed portion of the wedge shape. By this dynamic pressure, the main shaft 24 is brought into a non-contact state with respect to the sliding bearing member 36 and rotatably supported.

The pressurized air supplied to the air passage 70 flows out (sprays) from the annular passage 68 to the annular gap 48, flows to the side of the expansion chamber 62 via the annular gap 48, and flows out from the annular gap 48 to the expansion chamber 62. Inside. The pressurized air that has flowed out into the expansion chamber 62 flows as bubbles in the lubricating oil filled in the expansion chamber 62, and is discharged to the outside of the casing assembly 12 from the upper exhaust passage 74. The expansion chamber 62 has a volume that forms an oil groove and is useful for gas-liquid separation, whereby good gas-liquid separation can be performed in the expansion chamber 62. Thereby, the lubricating oil discharged from the exhaust passage 74 can be reduced, and the supply amount of the lubricating oil supplied to the casing assembly 12 can be reduced.

The discharge of the pressurized air is performed by the exhaust passage 74, whereby the internal pressure of the expansion chamber 62 is not raised by the pressurized air, and the back pressure is not increased, but flows to the expansion chamber via the annular gap 48. The flow of the pressurized air on the side of the 62 side becomes reliable, and accordingly, the outflow of the pressurized air flowing from the annular space 48 into the expansion chamber 62 can be surely maintained in a state of a large flow rate. Secondly, the inflow of the lubricating oil flowing into the annular space 48 by the expansion chamber 62 is prevented by the pressure of the lubricating oil in the expansion chamber 62 being higher than the pressure of the lubricating oil in the expansion chamber 62 in which the atmosphere is opened. The lubricating oil of the expansion chamber 62 can be surely prevented from leaking to the outside through the annular gap 48 without causing heat. This is done in a non-contact manner that does not produce rotational friction and therefore does not cause heat or wear.

Thereby, the lubricating oil is immersed in the arrangement portion of the sliding bearing member 36. In the spindle device 10, heat generation or abrasion is not caused, and the leakage of the lubricating oil to the outside of the casing assembly 12 can be surely prevented.

Further, since the pressurized air flows out through the annular passage 68 and spread over the entire area of the annular gap 48, it is possible to more reliably prevent the lubricating oil from leaking to the outside through the annular gap 48. Further, since the expansion chamber 62 is a space that is expanded from the annular space 48, the flow of the pressurized air flowing from the annular space 48 to the expansion chamber 62 can be performed well. Thereby, the effect of preventing the lubricating oil of the expansion chamber 62 from leaking to the outside through the annular gap 48 is improved.

In the event that the lubricating oil leaks from the annular gap 48 toward the front side, a labyrinth seal 72 is formed due to a portion of the pressurized air flowing from the annular passage 68 to the front side of the annular passage 68 (away from the side of the expansion chamber 62), Thereby, the flow can be interrupted, and the leakage of the lubricating oil from the annular gap 48 to the outside does not occur. This results in a fail-safe effect.

The present invention has been described with reference to the preferred embodiments of the present invention. It is to be understood by those skilled in the art that the present invention is not limited thereto, and may be appropriately modified without departing from the scope of the invention. For example, the outflow of the pressurized air with respect to the annular gap 48 may be performed from the side (front side) of the partition wall 18A away from the sliding bearing member 36 by the air passage constituting member independent of the partition wall 18A. Further, the oil discharge passages 75 and 76 may be connected to an oil drain pump for forced oil discharge. The slinger 50 can also be fixed to the outer circumference of the main shaft 24 instead of being fixed to the inner circumference of the front housing member 14. Further, the constituent elements shown in the above embodiments are not necessarily all necessary, and can be appropriately selected and used without departing from the scope of the present invention.

The case became the basis for claiming priority based on the Paris Treaty The disclosure of the Japanese Patent Application No. 2014-219704, filed on Oct. 28, 2014, the disclosure of which is hereby incorporated by reference in its entirety in its entirety in its entirety in

Claims (5)

A spindle device comprising: a main shaft, a sliding bearing member supporting a journal portion of the main shaft, and a housing accommodating the main shaft and the sliding bearing member, and immersing the sliding bearing member in lubricating oil, the housing including a front end member, the aforementioned The front end member has a partition wall that surrounds the extension portion of the main shaft that protrudes from the sliding bearing member and protrudes from the outside of the housing, and has an opening that is away from the side of the sliding bearing member. An annular gap is defined between the outer circumferences of the main shafts, and the front end member includes an air passage, and the air passage is defined to communicate with the annular gap only between the outer circumference of the main shaft and the outer circumference of the main shaft. An annular passage, and only pressurized air is sprayed from the annular passage toward the annular space, the spindle device further having an exhaust passage that faces the outer side of the housing between the sliding bearing member and the partition wall open. A spindle device according to claim 1, wherein a gas seal is formed on a side farther from the aforementioned sliding bearing member than the aforementioned air passage. A spindle device according to claim 1 or 2, wherein an expansion chamber that expands outward in the radial direction is defined between the sliding bearing member and a side of the partition wall facing the sliding bearing member. The spindle device of claim 1 or 2, wherein an oil retaining ring is attached to an end portion of the sliding bearing member remote from the partition wall, and the oil retaining ring is shrunk a gap between the inner circumference of the housing and the outer circumference of the spindle, and the slinger is mounted on one of the inner circumference of the housing and the outer circumference of the spindle in a non-contact state with respect to the other, and the spindle device has The lubricating oil supply passage, the lubricating oil supply passage supplies a lubricating oil that is closer to the side of the sliding bearing member than the oil retaining ring. The spindle device of claim 3, wherein an oil retaining ring is attached to an end portion of the sliding bearing member remote from the partition wall, the oil retaining ring narrowing a gap between an inner circumference of the housing and an outer circumference of the spindle, and the oil retaining The ring is mounted on the inner circumference of the casing and the outer circumference of the main shaft in a non-contact state with respect to the other, and the spindle device has a lubricating oil supply passage, and the lubricating oil supply passage is supplied more than the oil retaining ring. The lubricating oil on the side of the aforementioned sliding bearing member.