JP2012077900A - Thrust bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thrust bearing that can be used even in a high temperature environment, requires no large installation space, and is adaptable to such a case that a pressure distribution is formed when a spiral groove for dynamic pressure generation is formed.SOLUTION: The thrust bearing 1 is an annular bearing to be fitted onto a rotation shaft 2 so as to oppose to a thrust collar 3 provided on the rotation shaft 2. The thrust bearing includes: a bearing plate 4 disposed opposing to the thrust collar 3; and a support plate 5 which is disposed opposing to a face of the bearing plate 4 in an opposite side to the face opposing to the thrust collar 3, and supports the bearing plate 4. Ring springs 6, 7 are disposed, between the bearing plate 4 and the support plate 5, along a circumference direction of the rotation shaft while they are fitted onto the rotation shaft 2.

Description

  The present invention relates to a thrust bearing.

  Conventionally, as a bearing for a high-speed rotating body, a thrust bearing is known that is disposed so as to face a thrust collar provided on a rotating shaft. Among such thrust bearings, in the thrust dynamic pressure bearing using the dynamic pressure effect, for example, a spiral groove is formed on the bearing surface, and a lubricating film composed of an air layer is formed between the thrust collar and the bearing surface. The rotating shaft is supported through the lubricating film.

  By the way, in such a thrust hydrodynamic bearing, a plate-like elastic body is used so that the bearing surface can follow the thrust collar even if the thrust collar fluctuates due to the vibration of the rotary shaft. A structure in which the sliding surface) can follow the runout of the thrust collar is known (see Patent Document 1).

JP-A-62-288719

  However, in the thrust bearing having the above structure, since the elastic body is made of a plate-like rubber, the high temperature durability of the elastic body is low. Therefore, there is a problem in terms of maintenance, such as when it is necessary to replace the elastic body frequently when the use condition is a high temperature environment such as a turbocharger. In general, rubber and soft resin have a spring constant that is not linear, and thus cannot be said to be able to sufficiently follow the deflection on the rotating shaft side.

  Therefore, it can be considered that the rubber elastic body is replaced with, for example, a coil spring. However, in order to form a sufficiently soft coil spring that can accommodate a lubricating film made of an air layer, the coil diameter is increased or the number of turns is increased to increase the coil length (height). ), Etc., and the whole becomes large. However, since the bearings are usually arranged in a narrow space, if a large coil spring is used, the bearings will become larger correspondingly and may not fit in the space.

  In addition, when a spiral groove is formed on the bearing surface to form a lubricating film made of an air layer, for example, when the spiral groove is a pump-in type or a pump-out type, the pressure on the inner peripheral side or outer peripheral side of the bearing is reduced. Higher than the pressure on the opposite side. Therefore, it is necessary to cope with such a pressure distribution.

  The present invention has been made in view of the above circumstances, and has as its first object to provide a thrust bearing that can be used in a high temperature environment and that is relatively small in size and does not require a large installation space. Yes. It is a second object of the present invention to provide a thrust bearing that can cope with a case where a pressure distribution is formed when a spiral groove for generating dynamic pressure is formed.

The thrust bearing of the present invention is an annular thrust bearing that is externally attached to the rotating shaft, facing a thrust collar provided on the rotating shaft,
A bearing plate disposed opposite the thrust collar;
A bearing plate disposed opposite to the surface opposite to the surface facing the thrust collar of the bearing plate, and supporting the bearing plate;
A ring-shaped spring is disposed between the bearing plate and the support plate along the circumferential direction of the rotating shaft in a state of being extrapolated to the rotating shaft.

According to this thrust bearing, since the ring-shaped spring is disposed between the bearing plate and the support plate along the circumferential direction of the rotating shaft, the elastic deformation effect of the ring-shaped spring prevents vibration of the rotating shaft. The bearing surface of the bearing plate can follow the resulting runout of the thrust collar well.
Further, since the ring-shaped spring is usually formed of a coil made of metal, the high-temperature durability is remarkably higher than that of rubber or resin, and therefore, it can sufficiently be used in a high-temperature environment.
Moreover, the ring-shaped spring can be formed with desired rigidity by setting the wire diameter, the number of windings, the pitch (winding interval), the outer diameter and height of the ring, and the like as appropriate. Therefore, desired spring rigidity can be exhibited in a relatively small state without increasing the overall size. Therefore, it can suppress that the whole thrust bearing becomes large.
Furthermore, since the ring-shaped spring has an annular shape (ring shape), the ring-shaped spring can be uniformly arranged in the circumferential direction of the rotating shaft by being extrapolated around the rotating shaft.

In the thrust bearing, a spiral groove for generating dynamic pressure may be formed on a bearing surface of the bearing plate.
When a spiral groove for generating dynamic pressure is formed on the bearing surface, a pressure distribution is generated such that the pressure on the inner peripheral side and the outer peripheral side of the thrust bearing is higher than the pressure on the opposite side. Then, this pressure distribution tends to cause deformation on the bearing side particularly on the high pressure side. When such deformation occurs, the bearing surface of the bearing plate cannot follow the thrust collar surface runout well.
Therefore, by arranging the ring-shaped spring on the side where the pressure is lowered, for example, the rigidity on the side where the pressure is increased can be relatively increased, and deformation on the bearing side on the side where the pressure is higher can be suppressed.

Further, in this thrust bearing, a plurality of the ring-shaped springs are arranged in the radial direction of the rotating shaft between the bearing plate and the support plate,
The ring-shaped spring has two types, a ring-shaped spring having a relatively high spring rigidity and a low ring-shaped spring,
The ring-shaped spring having high spring rigidity is arranged on the side where the dynamic pressure generated by the spiral groove is high among the inner peripheral side which is the rotating shaft side and the outer peripheral side opposite thereto.
It is preferable that the ring-shaped spring with low spring rigidity is disposed on the side where the dynamic pressure generated by the spiral groove is low, of the inner peripheral side on the rotating shaft side and the outer peripheral side opposite thereto.
In this case, the ring-shaped spring having high spring rigidity is arranged on the high dynamic pressure side, and the ring-shaped spring having low spring rigidity is arranged on the low dynamic pressure side, so that the air layer generated by the spiral groove The bearing plate is not greatly deformed by the pressure distribution of the (lubricating film), and therefore the bearing surface of the bearing plate can better follow the runout of the thrust collar accompanying the vibration of the rotating shaft.

In the thrust bearing according to the present invention, since the ring-shaped spring is disposed between the bearing plate and the support plate, the bearing surface of the bearing plate is prevented from the runout of the thrust collar accompanying the vibration of the rotating shaft. Accordingly, it becomes possible to follow this well, so that the function as a bearing is exhibited well.
Further, since it can sufficiently cope with use in a high-temperature environment and can be formed in a relatively small size, a large installation space is not required, and therefore space can be saved.
Furthermore, it is possible to cope with a case where a pressure distribution is formed.

(A) is a sectional side view showing a schematic configuration of an embodiment of a thrust bearing according to the present invention, and (b) is a sectional view of an essential part showing a modification. (A) is a top view which shows the inner surface side of a bearing plate, (b) is a side view of a bearing plate, (c) is a top view which shows the inner surface side of a support plate. (A)-(c) is a top view which shows a bearing surface, (a) is a pump-in type, (b) is a pump-out type, (c) is a figure which shows a herringbone type. (A)-(d) is a figure which shows schematic structure of a ring-shaped spring, (a) is a perspective view, (b) is a top view, (c) is a side view, (d) is the front which shows the principal part. FIG. (A) is a perspective view showing a ring-shaped leaf spring having a C-shaped cross section, and (b) is a perspective view showing a ring-shaped leaf spring having a V-shaped cross section.

Hereinafter, the thrust bearing of the present invention will be described in detail.
1A and 2A to 2C are views showing an embodiment of a thrust bearing according to the present invention. FIG. 1A is a side sectional view of the thrust bearing, and FIG. Is a plan view showing the inner surface side of the bearing plate, (b) is a side view of the bearing plate, and (c) is a plan view showing the inner surface side of the support plate. In these drawings, reference numeral 1 is a thrust bearing, 4 is a bearing plate, and 5 is a support plate. The thrust bearing 1 is arranged by being extrapolated to a rotating shaft 2 that is mainly arranged in a horizontal direction (horizontal direction), such as a rotor shaft of a turbocharger or a turbo compressor. The thrust bearing of the present invention can be applied not only to the rotating shaft arranged in the horizontal direction as described above but also to the rotating shaft arranged in the vertical direction (vertical direction).

  The thrust bearing 1 is an annular (cylindrical) member disposed opposite to a disk-like thrust collar 3 fixed to the rotary shaft 2. Although FIG. 1A shows the thrust bearing 1 only on one side of the thrust collar 3, the thrust bearings 1 having the same configuration may be provided on both sides of the thrust collar 3, respectively.

  In the present embodiment, the thrust bearing 1 is disposed so as to face the bearing plate 4 disposed to face the thrust collar 3 and to the surface of the bearing plate 4 opposite to the surface facing the thrust collar 3. And the two kinds of ring-shaped springs 6 and 7 disposed between the bearing plate 4 and the support plate 5. The thrust bearing 1 is disposed in a casing 8 that is fixed to a main unit (not shown) such as a turbocharger, and is fixed by a bolt (not shown) and held in the casing 8.

  The bearing plate 4 is an annular plate having a through hole 4a for inserting the rotary shaft 2 as shown in FIGS. 1 (a), 2 (a) and 2 (b). The opposing surface is a bearing surface 4b. As shown in FIG. 3A, a spiral groove 9 for generating dynamic pressure is formed on the bearing surface 4b. The spiral groove 9 is a known pump-in type in the present embodiment, and a large number of spiral grooves 9a are arranged at equal intervals along the circumferential direction. These helical grooves 9a are formed to extend from the outer peripheral end of the bearing surface 4b to an annular land 9b provided around the through hole 4a. The land 9b has an outer surface at a relatively high position (outside position) with respect to the bottom surface of the spiral groove 9a. Note that a land (not shown) is also formed between the spiral grooves 9a and 9a.

  With such a configuration, the spiral groove 9 (spiral groove 9a) allows the outer peripheral side of the bearing surface 4b when the bearing surface 4b rotates relative to the thrust collar 3 (actually the thrust collar 3 rotates). Then, air is drawn into the inner peripheral side along the spiral groove 9a, whereby a lubricating film made of an air layer is formed between the thrust collar 3 and the bearing surface 4b. Further, the air drawn in by the spiral groove 9 (spiral groove 9a) collides with the land 9b so that the flow is blocked and the dynamic pressure is maintained, so that the pressure is maintained particularly on the inner peripheral side of the bearing plate 4. It is getting higher. That is, the air layer (lubricating film) formed by the spiral groove 9 (spiral groove 9a) has a pressure distribution that is higher on the inner peripheral side than on the outer peripheral side of the bearing surface 4b.

  Further, as shown in FIGS. 1 (a), 2 (a) and 2 (b), the bearing plate 4 has a plurality of (this embodiment) on the surface opposite to the bearing surface 4b, that is, on the periphery of the inner surface. In the embodiment, four (4) engaging projections 15 are formed. These engagement convex portions 15 are arranged at equal intervals in the circumferential direction of the bearing plate 4 and engage with notches in the support plate 5 described later.

  As shown in FIGS. 1 (a) and 2 (c), the support plate 5 is in the shape of an annular plate (substantially cylindrical) having a through hole 5a through which the rotary shaft 2 is inserted. Is disposed to face the surface (inner surface) opposite to the bearing surface 4b. The support plate 5 is fixed to the casing 8 with bolts (not shown), and is thus held in the casing 8 in a fixed state.

The support plate 5 is formed with two grooves 10 and 11 along the circumferential direction on the surface (inner surface) facing the bearing plate 4. These grooves 10 and 11 are circular in plan view arranged concentrically around the through hole 5a. In this embodiment, the groove 10 on the inner peripheral side is more than the groove 11 on the outer peripheral side in this embodiment. Deeply formed.
A plurality (four in this embodiment) of notches 16 are formed outside the outer peripheral groove 11. These notches 16 are arranged at equal intervals in the circumferential direction of the support plate 5 and are engaged (fitted) to the engaging projections 15 as shown in FIG. In addition, about these notches 16, it is good also as a notch recessed part which does not cut out the support plate 5 from the inner surface side to the outer surface side but cuts out a part of inner surface side.

Under such a configuration, the engaging convex portion 15 and the notch 16 constitute a detent mechanism that prevents the bearing plate 4 from rotating relative to the support plate 5 in the circumferential direction. Yes.
The width of the notch 16 is formed to be slightly larger than the width in the circumferential direction of the engaging convex portion 15, and when the engaging convex portion 15 is engaged with the notch 16, the engaging convex portion 15 In contrast, a slight gap is formed in the circumferential direction. Accordingly, the rotation prevention mechanism allows the bearing plate 4 to rotate slightly relative to the support plate 5.

  A ring-shaped spring 6 is disposed in the groove 10 on the inner circumferential side with the rotating shaft 2 being extrapolated, and a ring-shaped spring 7 is disposed in the groove 11 on the outer circumferential side with the rotating shaft 2 being extrapolated. Has been placed. Since these ring-shaped springs 6 and 7 are annular (ring-shaped), they can be uniformly arranged in the circumferential direction of the rotating shaft 2 by extrapolating the rotating shaft 2 around the rotating shaft 2. . Further, these ring-shaped springs 6 and 7 are disposed in contact with the bearing plate 4, whereby the support plate 5 supports the bearing plate 4 via the ring-shaped springs 6 and 7. . Therefore, since the ring-shaped springs 6 and 7 are arranged uniformly in the circumferential direction of the rotating shaft 2, the support plate 5 causes the bearing plate 4 to be uniform in the circumferential direction through these ring-shaped springs 6 and 7. It comes to support.

  Here, the support plate 5 is disposed in the casing 8 and is fixed to the casing via a fixing member. Further, the bearing plate 4 is disposed in the casing 8 together with the support plate 5. However, as described above, the bearing plate 4 is fixed to the support plate 5 in a state where slight rotation is allowed by the rotation preventing mechanism. Therefore, the bearing plate 4 is fixedly held in the casing 8 with a degree of freedom sufficient to follow the surface runout of the thrust collar 3.

  As shown in FIGS. 4A to 4C, the ring springs 6 and 7 are formed in a ring shape by connecting both ends of a coil made of metal, that is, a predetermined length. One coil spring is rounded into a ring shape, and both ends of the coil spring are connected to form a circle, that is, a ring shape. In the present embodiment, the ring-shaped springs 6 and 7 receive a load in the direction indicated by the arrow in FIG. 4D, and the two-dot chain line in FIG. 4D corresponds to the magnitude of the load. As shown, it is crushed and elastically deformed. At that time, the ring-shaped springs 6 and 7 have good linearity in their spring constants.

  Therefore, such ring-shaped springs 6 and 7 have appropriate wire diameter, number of turns, pitch (winding interval), and the outer diameter and height of the rings shown in FIGS. 4B and 4C. By setting, the spring rigidity can be formed to a desired strength. In this embodiment, in order to make it easy to visually recognize the difference in spring rigidity, the height of the ring-shaped spring 6 is made larger than the height of the ring-shaped spring 7, and the outer diameter of the ring-shaped spring 6 is set outside the ring-shaped spring 7. The spring stiffness of the ring-shaped spring 6 is made higher than the spring stiffness of the ring-shaped spring 7 by making it smaller than the diameter and changing other conditions as appropriate between the springs 6 and 7 as necessary.

  Therefore, in this embodiment, the ring-shaped spring 6 having relatively high spring rigidity is disposed on the inner peripheral side where the pressure (dynamic pressure) of the air layer (lubricating film) formed by the spiral groove 9 is increased, The ring-shaped spring 6 having relatively low spring rigidity is disposed on the outer peripheral side where the pressure (dynamic pressure) is lowered.

Next, the operation of the thrust bearing 1 having such a configuration will be described.
When the rotating shaft 2 shown in FIG. 1 rotates at a high speed, an air layer (lubricating film) is formed between the thrust collar 3 and the bearing surface 4b of the bearing plate 4 by the dynamic pressure generated in the spiral groove 9. Thus, the thrust bearing 1 supports the thrust collar 3 through the formed air layer.

  Further, the rotation shaft 2 may vibrate with slight rotation due to the influence of the external environment or operating conditions. In this case, the thrust collar 3 fixed to the shaft 2 vibrates slightly, causing surface runout. To do. At this time, in the thrust bearing 1 of the present embodiment, the ring-shaped springs 6 and 7 are arranged along the circumferential direction of the rotating shaft 2 between the bearing plate 4 and the support plate 5. Due to the elastic deformation effect of the springs 6 and 7, the bearing surface 4 b of the bearing plate 4 can follow the surface runout of the thrust collar 3 accompanying the vibration of the rotating shaft 2 in a favorable manner.

  Further, since the ring-shaped spring 6 having high spring rigidity is arranged on the inner peripheral side where the dynamic pressure is particularly high and the ring-shaped spring 7 having low spring rigidity is arranged on the outer peripheral side where the dynamic pressure is low, it is generated by the spiral groove 9. The bearing plate 4 is not greatly deformed by the pressure distribution of the air layer (lubricating film). Therefore, the bearing surface 4b of the bearing plate 4 can follow the surface runout of the thrust collar 3 accompanying the vibration of the rotating shaft 2 better.

Therefore, according to the thrust bearing 1 of the present embodiment, since the ring-shaped springs 6 and 7 are disposed between the bearing plate 4 and the support plate 5, the bearing surface 4 b is good against the surface runout of the thrust collar 3. Therefore, the function as a bearing can be exhibited satisfactorily.
In particular, even when there is a pressure distribution in the air layer (lubricant film) generated by the spiral groove 9, the ring-shaped springs 6 and 7 having different spring stiffness are arranged correspondingly, so that the surface runout of the thrust collar 3 can be reduced. On the other hand, the bearing surface 4b follows well, and the function as a bearing can be exhibited well.

Further, since the ring-shaped springs 6 and 7 are formed of a coil made of metal, the high-temperature durability is remarkably higher than that of rubber or resin, and therefore, the ring-shaped springs 6 and 7 can sufficiently cope with use in a high temperature environment.
Moreover, the ring-shaped springs 6 and 7 can be formed to have a desired strength by appropriately setting the wire diameter, the number of turns, the pitch (winding interval), the outer diameter and height of the ring, and the like. it can. Therefore, desired spring rigidity can be exhibited in a relatively small state without increasing the overall size. Therefore, it is possible to suppress an increase in the size of the entire thrust bearing, thereby reducing the space for installing the thrust bearing 1.

  Furthermore, since the ring-shaped springs 6 and 7 are annular (ring-shaped), the ring-shaped springs 6 and 7 can be uniformly arranged in the circumferential direction of the rotary shaft 2 by being extrapolated around the rotary shaft 2. Therefore, the support plate 5 can uniformly support the bearing plate 4 in the circumferential direction via the ring-shaped springs 6 and 7, thereby improving the bearing surface 4 b against the runout of the thrust collar 3. Can be followed.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.
For example, in the above embodiment, the case where the spiral groove 9 is formed on the bearing surface 4b of the bearing plate 4 to generate a dynamic pressure having a large pressure distribution has been described. However, when such a large pressure distribution is not formed. The present invention can also be applied.

  Moreover, in the said embodiment, although the rotation prevention mechanism was formed by the engagement convex part 15 and the notch 16, it replaced with these engagement convex part 15 and the notch 16, and as shown in FIG.1 (b), a bearing plate 4 and the support plate 5 are formed with mounting holes 17 respectively, and pins are inserted between the mounting holes 17 and 17 to prevent the bearing plate 4 from rotating relative to the support plate 5. It may be. In this case, the pin 18 is fixed to one of the mounting holes 17 and 17 and inserted into the other in a detachable manner. Also in this case, the pin 18 is fitted to the other of the mounting holes 17 and 17 with a clearance so that the bearing plate 4 is allowed to rotate slightly, It is fixed to the support plate 5.

  In the above embodiment, the known pump-in shape shown in FIG. 3A is adopted as the spiral groove 9, but a known pump-out in which a spiral groove 12a as shown in FIG. 3B is formed. It is also possible to adopt a shape or a known herringbone shape as shown in FIG. At that time, in the case of the pump-out type shown in FIG. 3 (b), the pressure increases on the outer peripheral side, so in order to cope with this, a ring-shaped spring having a relatively high spring rigidity is provided on the outer peripheral side. By disposing a ring-shaped spring having relatively low spring rigidity on the inner peripheral side, the bearing surface 4b can be made to follow the surface runout of the thrust collar 3 satisfactorily.

  Further, as shown in FIG. 3C, a pump-in type spiral groove 9a is formed on the outer peripheral side, a pump-out type spiral groove 12a is formed on the inner peripheral side, and a land 13 is formed between them. In the case of the formed herringbone shape, the pressure (dynamic pressure) is highest at a position corresponding to the land 13. Therefore, for example, a ring-shaped spring having high spring rigidity is arranged at a position corresponding to the land 13, and the outer peripheral side where the pump-in spiral groove 9a is formed and the pump-out spiral groove 12a are formed. You may make it arrange | position a ring-shaped spring with high spring rigidity to an inner peripheral side, respectively.

  That is, in the present invention, the ring-shaped spring disposed between the bearing plate 4 and the support plate 5 is not limited to two, and may be three or more or one. In the case of using only one, for example, when dynamic pressure is generated by a spiral groove, a ring-shaped spring is arranged on the side where the pressure (dynamic pressure) decreases. Thereby, the rigidity on the side where the pressure is increased can be relatively increased, and deformation on the bearing side on the side where the pressure is higher can be suppressed.

  Further, in the above embodiment, the spring stiffness of the ring-shaped spring 6 is increased by making the height of the ring-shaped spring 6 greater than the height of the ring-shaped spring 7 as shown in FIG. However, the ring spring has a desired spring strength by appropriately setting the wire diameter, the number of turns, the pitch (winding interval), the outer diameter and height of the ring, etc. as described above. Can be formed. Therefore, for example, the spring rigidity of the ring-shaped spring 6 and the spring rigidity of the ring-shaped spring 7 may be made different by making the height of the ring the same and changing other conditions.

Further, instead of the ring-shaped springs shown in FIGS. 4A to 4D, for example, a ring-shaped leaf spring having a C-shaped cross section as shown in FIG. 5A or shown in FIG. A ring-shaped leaf spring having a V-shaped cross section can also be used.
Moreover, you may combine a disc spring and a wave spring.

DESCRIPTION OF SYMBOLS 1 ... Thrust bearing, 2 ... Rotating shaft, 3 ... Thrust collar, 4 ... Bearing plate, 5 ... Support plate, 6, 7 ... Ring-shaped spring, 9 ... Spiral groove, 15 ... Engaging convex part, 16 ... Notch

Claims (3)

Opposed to a thrust collar provided on the rotating shaft, an annular thrust bearing that is extrapolated to the rotating shaft,
A bearing plate disposed opposite the thrust collar;
A bearing plate disposed opposite to the surface opposite to the surface facing the thrust collar of the bearing plate, and supporting the bearing plate;
A thrust bearing, wherein a ring-shaped spring is disposed between the bearing plate and the support plate along a circumferential direction of the rotary shaft in a state of being extrapolated to the rotary shaft.   The thrust bearing according to claim 1, wherein a spiral groove for generating dynamic pressure is formed on a bearing surface of the bearing plate. Between the bearing plate and the support plate, a plurality of the ring springs are arranged in the radial direction of the rotating shaft,
The ring-shaped spring has two types, a ring-shaped spring having a relatively high spring rigidity and a low ring-shaped spring,
The ring-shaped spring having high spring rigidity is arranged on the side where the dynamic pressure generated by the spiral groove is high among the inner peripheral side which is the rotating shaft side and the outer peripheral side opposite thereto.
The ring-shaped spring having low spring rigidity is arranged on the side where the dynamic pressure generated by the spiral groove is low, on the inner peripheral side on the rotating shaft side and on the opposite outer peripheral side. The thrust bearing according to claim 2.

Images