TWI635225B - Hydrodynamic fluid bearing structure and the manufacture method of the same - Google Patents

Abstract

The present invention discloses a dynamic pressure bearing, the dynamic pressure bearing has a bearing body, the bearing body is mounted inside a casing for supporting a rotating shaft; the center of the bearing body has a rotating shaft hole, and the rotating shaft is disposed in the rotating shaft hole; The outer side surface of the bearing body further has a flat portion extending from the upper end of the bearing body to the lower end of the bearing body in a direction parallel to the central axis of the shaft hole, when the bearing body is disposed inside the outer casing, the plane portion and the An escape passage communicating from the lower end of the bearing body to the upper end of the bearing body is formed between the inner side walls of the outer casing. The invention has the beneficial effects that the volume of the escape passage can be increased, and the occurrence of burrs during the processing of the bearing body is avoided.

Description

Dynamic pressure bearing and manufacturing method thereof

The present invention relates to a dynamic pressure bearing and a method of manufacturing the same, and more particularly to a liquid dynamic pressure bearing having an escape structure and a method of manufacturing the same.

In the prior art, the cooling fan is one of the main components in the heat dissipation module. In recent years, in order to cope with the trend of miniaturization, thinning, and increasing processor operating power of information products such as notebook computers and tablet computers, the heat dissipation module must also be miniaturized, thinned, and simultaneously Take into account the direction of improving heat dissipation efficiency. Therefore, the fan used in the heat dissipation module must have the advantages of specific product reduction, thickness reduction, and fan speed increase. In order to meet the demand for miniaturization, thinning and high speed of fans, a considerable number of cooling fans have been replaced by conventional dynamic bearings.

However, when the dynamic pressure bearing is running, hot air is generated when the shaft core and the wear piece are in contact with each other. If the hot air is not discharged, the shaft core cannot be stably rotated. Therefore, an air escape structure must be provided on the dynamic pressure bearing for discharging hot air. . An escape design of a conventional dynamic pressure bearing is to provide a plurality of axial escape grooves on the outer surface of the bearing body, and the hot air can be discharged through the escape grooves.

The current design of the escaping of the dynamic pressure bearing has the following disadvantages: (1) Due to the limited depth and width of the escaping groove, the escaping groove volume that can be provided is limited, so that the hot gas discharge capacity is limited and the buffer is lacking. (2) Because the external shape of the dynamic pressure bearing is mostly formed by turning, the outer side of the bearing body is provided with an escape groove. At the time, it is easy to produce a burr at the edge of the escape groove, and the turned chips are easily caught in the escape groove, which causes inconvenience in cleaning the burrs and chips after the processing is completed.

The technical problem to be solved by the present invention is that the escape groove of the bearing body of the conventional dynamic pressure bearing is designed to have insufficient exhaust gas and is prone to burrs and chipping defects.

The embodiment of the present invention provides a dynamic pressure bearing, which is installed inside a casing for supporting a rotating shaft. The dynamic pressure bearing includes: a bearing body, and the bearing body is sleeved on the outer casing. Internally, a center of the bearing body has a shaft hole penetrating from an upper end of the bearing body to a lower end of the bearing body, the rotating shaft is disposed in the shaft hole; the outer side of the bearing body further has a flat portion extending from an upper end of the bearing body to a lower end of the bearing body in a direction parallel to a central axis of the rotary shaft hole, when the bearing body is disposed inside the outer casing, An escape passage communicating from the lower end of the bearing body to the upper end of the bearing body is formed between the flat portion and the inner side wall of the outer casing.

In a preferred embodiment of the present invention, the outer surface of the bearing body forms a cylindrical surface except the plane portion, the cylindrical surface and the shaft hole are concentric; the central axis of the shaft hole is The pitch of the cylindrical surface is defined as a first pitch; a vertical pitch of the central axis of the spindle hole and the planar portion is defined as a second pitch; and the first pitch is greater than the second pitch.

In a preferred embodiment of the present invention, the upper end of the bearing body has a first end surface; the space inside the housing for accommodating the bearing body is defined as a first accommodating space, and the first accommodating space The upper end of the space has an open end, and the inner side of the open end is provided with an annular member, and the bottom side of the annular member is close to the bearing when the bearing body is received in the first accommodating space a first end surface of the body; a spacing between a central axis of the shaft hole and an inner side wall of the annular member is defined as a third spacing; the third spacing is greater than the second spacing and less than The first spacing is described.

In a preferred embodiment of the present invention, the difference between the first pitch and the second pitch is between 0.1 times the range of the first pitch to 0.3 times the first pitch.

In a preferred embodiment of the present invention, the difference between the third pitch and the second pitch is greater than 0.001 mm.

In a preferred embodiment of the present invention, the difference between the third pitch and the second pitch is between 0.0015 mm and 0.01 mm.

In a preferred embodiment of the present invention, the lower end of the first accommodating space is connected to a second accommodating space, and the bottom end of the rotating shaft hole of the bearing body and the second accommodating space are in communication with each other; The inner side wall of the shaft hole is provided with a plurality of oil guiding grooves, and a gap between the rotating shaft hole and an outer side wall of the rotating shaft, and the second receiving space is filled with lubricating grease.

In a preferred embodiment of the present invention, the bottom of the second accommodating space is provided with a wear-resistant piece, and the bottom end of the rotating shaft penetrates the lower end of the bearing body and contacts the wear-resistant piece.

In a preferred embodiment of the present invention, the second accommodating space and the bottom surface of the bearing body have a spacing to form a third accommodating space, and the bottom end of the rotating shaft is connected to a thrust plate. The thrust plate is received in the third accommodating space.

An embodiment of the present invention further provides a manufacturing method for manufacturing the dynamic pressure bearing, comprising the steps of: preparing a rod-shaped substrate; forming the rod-shaped substrate into a same sectional shape as the bearing body After the blank is cut, the cut blank is made into the bearing body.

The invention has the beneficial effects that the volume of the escape passage can be increased to improve the exhaust effect, and the occurrence of burrs during the processing of the bearing body and the engagement of the chips with the exhaust groove can be avoided.

In order to further understand the features and technical contents of the present invention, reference should be made to the following detailed description and drawings of the present invention. The test and description are not intended to limit the invention.

1‧‧‧Dynamic bearing

10‧‧‧ Shell

11‧‧‧First accommodation space

12‧‧‧Second accommodation space

13‧‧‧ Third accommodating space

14‧‧‧Open end

15‧‧‧ ring members

16‧‧‧ wear-resistant film

17‧‧‧ escape route

18‧‧‧ bottom member

20‧‧‧ bearing body

21‧‧‧ shaft hole

22‧‧‧Flat Department

23‧‧‧ cylindrical surface

24‧‧‧ first end face

25‧‧‧Outstanding

26‧‧‧ Oil guide groove

27‧‧‧ Groove

28‧‧‧ card slot

29‧‧‧ shaft seal

30‧‧‧ shaft

31‧‧‧ push plate

40‧‧‧ rod-shaped substrate

40a‧‧‧Bullen

41a‧‧‧Cylindrical surface

42a‧‧‧Flat Department

D1‧‧‧first spacing

D2‧‧‧second spacing

D3‧‧‧ third spacing

C‧‧‧ center axis

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view showing the combination of a dynamic pressure bearing according to an embodiment of the present invention.

2 is a perspective view of a bearing body employed in one embodiment of the present invention.

Figure 3 is a cross-sectional view of a bearing body employed in one embodiment of the present invention.

4 is a top plan view of a bearing body used in one embodiment of the present invention.

Fig. 5 is a top plan view showing the combination of a dynamic pressure bearing according to an embodiment of the present invention.

Fig. 6 is a schematic view showing the processing flow of a bearing body used in one embodiment of the present invention.

The following is a description of embodiments of the present invention relating to "fan assembly and its bearing assembly" by way of specific embodiments, and those skilled in the art can understand the advantages and effects of the present invention from the disclosure of the present specification. The present invention may be carried out or applied in various other specific embodiments, and various modifications and changes can be made without departing from the spirit and scope of the invention. In addition, the drawings of the present invention are merely illustrative and are not intended to be stated in the actual size. The following embodiments will further explain the related technical content of the present invention, but the disclosure is not intended to limit the scope of the present invention.

As shown in FIG. 1, the present invention provides a dynamic pressure bearing 1 comprising: a housing 10, a bearing body 20, and a rotating shaft 30. The outer casing 10 has a substantially cylindrical cross-sectional shape. The inner portion of the outer casing 10 defines a cylindrical first accommodating space 11. The upper end of the first accommodating space 11 has an open end and is disposed at the lower end of the outer casing 10. There is a bottom member 18 for forming the bottom of the outer casing 10 in a sealed state.

The bearing body 20 is received in the interior of the first accommodating space of the outer casing 10. The bearing body 20 generally defines a circular cylinder having a flat portion 22 on one side, the diameter of the bearing body 20 and the first accommodating space of the outer casing 10. 11 is matched so that the bearing body 20 can be accommodated in the first accommodating space 11. The outer side surface of the bearing body 20 is further provided with at least one groove 27 for allowing the bearing body 20 to be smoothly placed in the first receiving space. Within 11 rooms. The upper end of the bearing body 20 has a first end surface 24, and a smaller diameter protruding end 25 is further disposed on the first end surface 24, so that the upper end of the bearing body 20 is formed in a class shape.

The inner side of the open end 14 of the first accommodating space 11 has an annular member 15. As shown in FIGS. 1 and 5, the inner diameter of the annular member 15 is smaller than the outer diameter of the bearing body 20 and slightly larger than the outer diameter of the protruding end 25, when the bearing body 20 is assembled inside the outer casing 10, the annular member 15 The bottom surface is pressed against the first end surface 24 of the bearing body 20, thereby positioning the bearing body 20 in the first accommodating space, and the protruding end 25 of the bearing body 20 is received inside the annular member 15.

The center of the bearing body 20 has a shaft hole 21 extending from the upper end of the bearing body 20 to the lower end of the bearing body 20. The inner diameter of the shaft hole 21 and the outer diameter of the shaft 30 are matched to each other so that the shaft 30 can be passed through The inside of the shaft hole 21. A bottom member 18 is disposed under the first accommodating space 11 of the outer casing 10, so that the lower end of the first accommodating space 11 is closed, and a central portion of the top surface of the bottom member 18 has a concave portion to form a second accommodating space 12. The second accommodating space 12 and the first accommodating space 11 communicate with each other. When the rotating shaft 30 is placed in the rotating shaft hole 21, the end of the rotating shaft 30 extends into the second accommodating space 12. The bottom surface of the second accommodating space 12 is further provided with a wear-resistant piece 16, and the bottom of the rotating shaft 30 can be in contact with the top surface of the wear-resistant piece 16, thereby reducing the frictional resistance of the end of the rotating shaft 30. Further, an annular card slot 28 is disposed on the inner side of the upper end of the shaft hole 21, and a shaft seal 29 is disposed in the card slot 28 to prevent grease from leaking from the upper end of the shaft hole 21 and to prevent dust from entering the shaft hole 21.

In this embodiment, a third accommodating space 13 is formed between the bottom surface of the bearing body 20 and the second accommodating space 12 and the upper end of the bottom member 18. As shown in FIG. 1, the bottom end of the rotating shaft 30 is further provided with a thrust plate 31. The thrust plate 31 is a circular plate body, and the thrust plate 31 is accommodated in the third receiving portion. In space 13. The surface of the thrust plate 31 is also provided with an oil guiding groove. When the thrust plate 31 rotates with the rotating shaft 30, the oil guiding groove 26 on the surface of the thrust plate 31 can also generate pressure to the lubricating grease, so that the thrust plate 31 is caused. Between the bottom side of the bearing body 20 and the top surface of the bottom member 18 The oil film is used to generate an axial pressure to improve the stability of the rotation of the shaft 30 and reduce vibration.

A gap is formed between the rotating shaft 30 and the inner side wall of the rotating shaft hole 21, and a gap between the rotating shaft 30 and the rotating shaft hole 21 and the second receiving space 12 are filled with lubricating grease. The shaft hole 21 and the rotating shaft 30 are precisely machined so that the gap between the outer diameter of the shaft hole 21 and the rotating shaft 30 can be controlled within a range of several micrometers, and the inner side wall of the shaft hole 21 is provided with a plurality of oil guiding grooves 26, Through the oil guiding groove 26, the lubricating grease can be guided to generate pressure when the rotating shaft 30 rotates, so that the oil film is not formed, so that the rotating shaft 30 does not directly contact the inner side wall of the rotating shaft hole 21, thereby reducing the frictional force of the rotating shaft 30, and Avoid shaft wear.

As shown in FIGS. 2 to 4, one side of the outer side surface of the dynamic pressure bearing 1 of the present invention has a flat portion 22 which is parallel from the upper end of the bearing body 20 to the central axis C of the rotary shaft hole 21. The direction extends to the lower end of the bearing body 20. At the same time, the outer side surface of the bearing body 20 forms a cylindrical surface 23 except for the area of the flat portion 22. As shown in FIG. 4, the flat portion 22 and the cylindrical surface 23 together constitute an outer side surface of the bearing body 20, the cylindrical surface 23 and the central axis C of the shaft hole 21 are concentric, and the diameter of the cylindrical surface 23 and the inner diameter of the first accommodating space 11 are matched to each other so that the bearing body 20 can be placed in the first accommodating space. As shown in FIG. 1, when the bearing body 20 is disposed inside the outer casing 10, there is a gap between the flat portion 22 and the inner side wall of the outer casing 10, and the gap constitutes a communication from the lower end of the bearing body 20 to An escape passage 17 at the upper end of the bearing body. Therefore, when the dynamic pressure bearing 1 is in operation, the hot air generated by the friction of the rotating shaft 30 and the wear plate 16 can flow from the second accommodating space 12 below the bearing body 20 to the upper end of the bearing body 20 via the escape passage 17, and from the first The open end 14 of the upper end of the accommodating space 11 is discharged.

As shown in FIGS. 4 and 5, the bearing body 20 has a substantially D-shaped cross-sectional shape. If the pitch of the central axis C and the cylindrical surface 23 is defined as the first pitch D1, the central axis C and the flat face 22 are defined. The vertical spacing is defined as the second spacing D2, and the spacing between the central axis C and the inner sidewall of the annular member 15 is defined as the third spacing D3, the first pitch D1, the second pitch D2, and the third pitch D3 have the following relationship.

The first spacing D1 is greater than the second spacing D2, and the third spacing D3 is less than the first spacing D1 being greater than the second spacing D2. The difference between the first spacing D1 and the second spacing D2 represents that between the planar portion 22 and the inner sidewall of the first receiving space 11 when the bearing body 20 is fitted into the first receiving space 11 of the outer casing 10. The height of the escape passage 17 formed. In a preferred embodiment of the present invention, the difference between the first pitch D1 minus the second pitch D2 is designed to be between 0.1 times the first pitch D1 to 0.3 times the first pitch D1, so as to escape The air passage has sufficient area for smooth exhaust. Therefore, if the bearing body having a diameter of 5 mm is taken as an example, the difference between the first pitch D1 and the second pitch D2 can be in the range of 0.5 mm to 1.5 mm.

In addition, the third spacing D3 is designed to be larger than the second spacing D2 and smaller than the first spacing D1. Therefore, as shown in FIG. 5, after the bearing body 20 is assembled inside the outer casing 10, the annular member is viewed in a plan view. The position of the inner side wall of 15 can be between the inner side wall of the first accommodation space 11 and the flat portion 22 of the bearing body 20, and a gap is maintained between the flat portion 22 and the inner side wall of the annular member 15.

As shown in FIG. 1, the bottom surface of the annular member 15 can be pressed against the first end surface 24 of the bearing body 20, thereby positioning the bearing body 20 in the first accommodating space 11 while the inner side wall of the annular member 15 A gap is maintained between the flat faces 22, thereby allowing gas in the escape passage 17 to pass through the gap between the inner side wall of the ring member 15 and the flat portion 22.

In particular, the gap between the inner side wall of the annular member 15 and the flat portion 22 is intended to be used for the gas in the escape passage 17, but it must be designed in addition to being able to maintain the exhaust gas smoothly. It must also be noted that the gap should not be too large to avoid leakage of grease into the escape passage 17, so that the width of the gap between the inner side wall of the annular member 15 and the flat portion 22 (i.e., the third pitch D3 minus) The difference of the second pitch D2 is preferably controlled to be 0.001 mm or more, and in a preferred embodiment, the width of the gap can be between 0.0015 mm and 0.01 mm. range.

As shown in Fig. 6, the manufacturing process of the bearing body 20 employed in the present invention will be described. The bearing body 20 of the present invention achieves the purpose of continuous rapid production by forming a blank from a rod-shaped raw material, and then cutting the blank to perform subsequent processing to form a finished product of the bearing body 20. In the manufacturing process of the bearing body 20 of the present invention, the following steps are schematically included, wherein the first step is to prepare a rod-shaped substrate 40, which preferably has a diameter close to the outer diameter of the bearing body 20. Round section body. The rod-shaped substrate 40 is then formed into a billet 40a having the same cross-sectional shape as the bearing body 20 by a suitable processing method. The billet 40a has a cylindrical surface 41a and a flat portion 42a. The cylindrical surface 41a coincides with the cylindrical surface 23 of the bearing body 20, and the flat portion 42a coincides with the flat portion 22 of the bearing body 20.

The processing method of the blank 40a may be, but not limited to, one or a combination of the following processing methods: (1) Stretch Forming: when the drawing process is used, the rod shape is used The substrate 40 is drawn through a drawing die having a D-shaped inner hole to cause plastic deformation of the rod-shaped substrate 40, so that the rod-shaped substrate 40 forms the blank 40a; or (2) cutting: In this method, after the cylindrical surface 41a is formed by machining such as turning or outer diameter polishing, the flat portion 42a is formed on one side of the blank 40a by milling or planar polishing.

After the forming step of the blank 40a is completed, a third step is subsequently performed. After the blank 40a is cut in accordance with a predetermined length of the bearing body 20, the cut blank is then processed into the bearing body 20.

The processing method of the bearing body 20 used in the present invention is characterized in that the bearing body 40a having the same sectional shape as that of the bearing body 20 is prepared in advance, and then the bearing body 20 is formed by using the blank 40a, so that it is not necessary to separately The finished product of the bearing body 20 performs the processing of the cylindrical surface 23 and the flat portion 22, so that the flow can be simplified and the manufacturing cost can be saved.

The dynamic pressure bearing 1 of the present invention has the above-mentioned design, and its beneficial effects are mainly as follows:

1. The side surface of the bearing body 20 of the present invention has a flat portion 22, and an escape passage 17 is formed by a gap between the flat portion 22 and the inner side wall of the first accommodation space 11 of the outer casing 10, so that the escape passage 17 The volume is larger than the volume of the escape groove used in the existing dynamic pressure bearing, so that the hot gas discharge is smoother, and the pressure generated by the expansion of the hot gas and the lubricating fluid after being heated can be buffered.

2. The bearing body 20 of the present invention adopts a design in which the air passage groove is replaced by the flat surface portion 22, so that there is no longitudinal groove structure on the outer side surface of the bearing body 20, so that the outer surface of the bearing body 20 is turned. (For example, when a machining program for forming the protruding end 25, the first end surface 24, and the groove 27, etc.) is not easily generated, and the cutting metal chips do not get caught in the groove, thereby avoiding the bearing body. 20 After finishing the processing, remove the burrs and clean the metal shavings.

The above disclosure is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Therefore, any equivalent technical changes made by using the present specification and the contents of the drawings are included in the application of the present invention. Within the scope of the patent.

Claims (10)

A dynamic pressure bearing is mounted inside a casing for supporting a rotating shaft, the dynamic pressure bearing includes: a bearing body, the bearing body is sleeved inside the casing, the bearing a center of the body has a shaft hole extending from an upper end of the bearing body to a lower end of the bearing body, the rotating shaft is disposed in the shaft hole; the outer side of the bearing body further has a plane portion a plane portion extending from an upper end of the bearing body to a lower end of the bearing body in a direction parallel to a central axis of the shaft hole, and when the bearing body is disposed inside the housing, the plane portion and An escape passage communicating from the lower end of the bearing body to the upper end of the bearing body is formed between the inner side walls of the outer casing. The dynamic pressure bearing according to claim 1, wherein an outer surface of the bearing body forms a cylindrical surface other than the planar portion, the cylindrical surface and the shaft hole being concentric; the center of the shaft hole The distance between the axis and the cylindrical surface is defined as a first spacing; the vertical spacing of the central axis of the shaft hole and the planar portion is defined as a second spacing; the first spacing is greater than the second spacing. The dynamic pressure bearing of claim 2, wherein the upper end of the bearing body has a first end surface; the space inside the outer casing for accommodating the bearing body is defined as a first accommodating space, the An upper end of an accommodating space has an open end, and an inner side of the open end is provided with an annular member, and when the bearing body is received in the first accommodating space, a bottom side of the annular member is close to a first end surface of the bearing body; a spacing between a central axis of the shaft hole and an inner sidewall of the annular member is defined as a third spacing; the third spacing is greater than the second spacing and less than the first spacing. The dynamic pressure bearing according to claim 3, wherein a difference between the first pitch minus the second pitch is between 0.1 times the range of the first pitch to 0.3 times the first pitch. The dynamic pressure bearing according to claim 4, wherein a difference between the third pitch and the second pitch is greater than 0.001 mm. The dynamic pressure bearing according to claim 5, wherein the difference between the third pitch and the second pitch is between 0.0015 mm and 0.01 mm. The dynamic pressure bearing according to any one of claims 1 to 6, wherein a lower end of the first accommodating space is connected to a second accommodating space, a bottom end of the shaft hole of the bearing body and the The second accommodating spaces are connected to each other; the inner side wall of the rotating shaft hole is provided with a plurality of oil guiding grooves, and a gap between the rotating shaft hole and the outer side wall of the rotating shaft, and the second accommodating space Filled with grease. The dynamic pressure bearing of claim 7, wherein a bottom of the second accommodating space is provided with a wear plate, a bottom end of the rotating shaft penetrating the lower end of the bearing body and contacting the wear piece . The dynamic pressure bearing of claim 8, wherein the second accommodating space and the bottom surface of the bearing body have a spacing to form a third accommodating space, and the bottom end of the rotating shaft is connected to a thrust a plate, the thrust plate being received in the third accommodating space. A manufacturing method for producing the dynamic pressure bearing according to any one of claims 1 to 9, comprising the steps of: preparing a rod-shaped substrate; forming the rod-shaped substrate into a bearing and the bearing a billet having the same cross-sectional shape of the main body; after the billet is cut, the cut billet is made into the bearing body.