JPS6110014Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to improvements in pivot pad bearings.

As shown in FIGS. 1 and 2, the conventional pivot pad bearing has three pad assemblies 02a, 02b, 0 at intervals of 120 degrees around the circumferential surface of a rotating shaft 01.
It is supported by 2c. The two pad assemblies 02a, 02c are connected to their pads 03a, 0.
Pivots 04a and 04c that pivot the pad 3c are fixed to support blocks 05a and 05c, and the pivot 04b that pivots the pad 03b of the other pad assembly 02b is attached to the support block 05b via a spring plate 06. It is being

Therefore, each of the support blocks 05a, 05
b and 05c are both fixed to the bearing casing 07. Therefore, in the pivot pad bearing configured in this way, even if the shaft 01 swings around, each pad will tilt accordingly, and the component force in the tangential direction, which is the swinging component, will be released, and each pad will be Since only a small amount of this component force acts on the shaft 01, and each pad is oriented in the direction of the load on the shaft 01, it is a quiet and somewhat stable bearing suitable for high speeds, providing a foothold for fully gas bearings. In the figure, the arrow mark indicates the direction of rotation of the rotating shaft 01.

However, in the bearing of the above embodiment type, when the shaft rotation starts and at low speeds, the contact between the shaft circumferential surface and the pressure receiving surface of the pads is reduced to a point where the so-called bearing clearance (gap between the shaft and the bearing surface) is large enough to be suitable for high speeds. It is unstable because it is set, and both parties arrive,
There is a large degree of fluttering. Furthermore, in order to distribute the bearing load when the shaft rotates at high speed, each pad is pivoted at a position approximately 65% of the pad length behind the leading edge relative to shaft rotation, so that the leading edge is aligned with the shaft surface. In addition, it is in a state where so-called lockups are likely to occur. These phenomena are caused by the pivot 04, which is fixedly erected on a single spring plate 06 and is configured to be easily tilted.
This phenomenon occurs particularly frequently in the pad 03b which is pivotally supported by the rotary shaft 03b and the pad 03c which has a large contact gap with the rotary shaft 01 in anticipation of the radial expansion of the rotary shaft 01 during high-speed operation. This not only leads to damage to the pressure-receiving surface of the pad, but also causes vibration and noise in the bearing.

The present invention was made to eliminate the above-mentioned problems of the conventional bearing, and in a bearing that supports each of the three divided surfaces of the circumference of the rotating shaft with a pivot pad,
The first pad assembly on the lower side of the rotation axis is integrally fixed to a support block so that its pivot axis can be adjusted forward and backward relative to the rotation axis, and is related to the rotation direction of the rotation axis with respect to the first pad assembly. The second pad assembly disposed on the leading side has its pivot axis fixed perpendicularly to a double structure of high and low rigid spring plates attached to a support block, and A stopper is provided on the support block with an adjustable clearance relative to the orthogonally fixed outer side of the third pad assembly, and a third pad assembly is provided on the trailing side of the first pad assembly in relation to the rotational direction of the rotating shaft. The assembly has its pivot axis fixed orthogonally to a double structure of low stiffness springs attached to a support block, and
A pivot pad characterized in that a support block is provided with a stopper whose clearance can be adjusted with respect to the orthogonally fixed outer side of a heavy structure, thereby significantly improving bearing characteristics when starting a rotating shaft and during low-speed rotation. The company provides bearings.

The present invention will be explained below based on an embodiment shown in FIG.

The figure is a cross-sectional view of a pivot pad type journal bearing, in which the rotating shaft 1 is installed horizontally, and the lower side of the bearing is shown in the figure.

In the figure, 2 is a bearing casing, 3a, 3
Pad assemblies b and 3c are fixed to the bearing casing 2 and support the circumferential surface of the rotating shaft 1 by dividing it into three equal parts, and the first pad assembly 3a at the lower position is directly attached to the rotating shaft 1. A pivot 5a pivotally supports a pad 4a that is in contact with the bearing casing 2, and the pivot 5a is integrally attached to a support block 6a fixed to the bearing casing 2 via an adjustment body 7a whose movement in the direction of the rotation axis can be adjusted. The pad assembly 3a rigidly supports the rotating shaft 1 via a pad 4a.

Adjustment of the forward and backward movement of the adjusting body 7a with respect to the support block 6a, which is necessary when assembling and setting the journal bearing and the rotating shaft 1, is performed by turning a nut-shaped hexagonal part 7'a formed at the inner end of the adjusting body 7a. Although this is done by moving the adjustment body, it is also possible to have a structure in which a rotating shaft passing through the bearing casing 2 extends on the outside of the adjustment body so that the adjustment body can be moved from the outside.

When the rotating shaft 1 is assumed to rotate counterclockwise in the figure, as indicated by the arrow symbol, the leading side of the first pad assembly 3a in relation to the rotational direction of the rotating shaft 1 (in the figure, the upper left diagonal direction) In the second pad assembly 3b disposed on the side), the pad 4b is pivoted by a pivot 5b, and the axis of the pivot 5b is connected to a support block 6b fixed to the bearing casing 2, and a rigid spring plate of two types, high and low. double structure 7
It is attached via b. 2 of the rigid spring plate
The heavy structure 7b allows vibration of the rotating shaft during high-speed rotation (steady rotation) and radial expansion of the rotating shaft itself due to heat and rotational centrifugal force. A high-rigidity spring plate 7'b having an elastic force substantially equivalent to the gas film dynamic pressure generated between the two, and a low-rigidity spring plate 7'' whose elasticity is negligible compared to the high-rigidity spring plate 7'b. b is a double structure with a gap between them, and is spanned over both ends of the support block 6b, and both spring plates 7'
The shaft end of the pivot 5b perpendicular to b, 7''b is fixedly supported. 8b is a stopper which is screwed through the support block 6b from the outside, and its tip is connected to the pivot shaft in the double structure 7b. The gap formed between the two is adjustable by screwing the stopper 8b in and out.
Since the axis of the pivot 5b is fixed perpendicularly to the two spring plates 7'b and 7''b which are spaced apart from each other, the assembly rigidity is large, and even if a lateral force is applied to the pivot axis, the axis will remain stable. The inclination fluctuation with respect to the spring plates 7'b and 7''b is so small that it can be ignored.

A third pad assembly 3c disposed on the trailing side (diagonally upper right side in the figure) with respect to the first pad assembly 3a is connected to the second pad assembly 3a.
Almost similar to the structure of the assembly 3b, the pads 4c,
It consists of a combination of a pivot 5c, a support block 6c, a double spring plate structure 7c and a stopper 8c, of which only the double spring plate structure 7c is different from that of the second pad assembly 3b. That is, the spring plate double structure 7c is composed of a thin low-rigidity spring plate 7'.
c, 7"c, and its elasticity is such that the pad 4c applies a pressure preload to the rotating shaft 1 via the pivot 5c, and its magnitude changes from the start of the rotating shaft 1 to high speed rotation. The spring plate is approximately equal to or less than the gas film dynamic pressure generated between the pad 4c and the rotating shaft 1 during low speed rotation during the transition operation, and the spring plate is bent by the gas film dynamic pressure from the middle of the transition operation to the high speed rotation. It is assumed that this will cause

However, since the bending displacement of the spring plate exceeding a predetermined value is prevented by the stopper 8c, the third pad assembly 3c in the state of being blocked by the stopper 8c as described above is Similar to the assembly 3a, the rotating shaft 1 is rigidly supported via a pad 4c.

The pivot position of each of the pads 4a, 4b, and 4c is at a rear position of about 65% of the pad length from the front edge, as in the conventional case.

In addition, the shaft sliding surface of each pad is coated with ceramic or Teflon, or subjected to surface hardening such as nitriding to prevent wear.

Next, we will explain the adjustment situation for comprehensively assembling each part of the present invention to the rotating shaft 1.The first pad assembly 3a and the second pad assembly 3
First, the rotary shaft 1 is supported by b. That is, in the first pad assembly 3a, the adjusting body 7a is moved forward and backward so that the pad 4a sets the rotating shaft 1 at a predetermined vertical position. In the second pad assembly 3b, the support block 6b is moved back and forth to set a predetermined left and right position of the rotating shaft 1. The stopper 8b is moved back and forth to provide a required clearance between the stopper 8b and the double structure 7b. This required clearance is such that the degree of bending displacement of the high-rigidity spring plate 7'b due to the dynamic load of the rotating shaft 1 does not cause permanent distortion or severe fatigue to the spring plate 7'b, and the bearing clearance is such that the degree of bending displacement of the high-rigidity spring plate 7'b due to the dynamic load of the rotating shaft 1 does not cause permanent distortion or severe fatigue, and the bearing clearance is This is the blocking interval of the stopper that prevents the condition from entering the unstable region, and is determined by design. Next, the third pad assembly 3c
, move its support block 6c back and forth, and press pad 4.
c is set so that it is in slight pressure contact with the rotating shaft 1, and the double structure 7c is moved forward and backward by the stopper 8c.
Set the clearance Cr to a predetermined interval. Generally, the clearance Cr is given as approximately 1/1000 of the radius of the rotating shaft 1.

Since the present invention is constructed as described above, the weight of the rotating shaft 1 is mainly supported by the pad 4a as it rotates when the rotating shaft 1 starts up and during low-speed rotation in the process of transitioning to high-speed rotation (steady rotation). . The rotating shaft 1 has a strong tendency to roll to the left in the drawing due to sliding resistance with the pressure-receiving surface of the pad 4a, and the pad 4b is supported by a highly rigid spring plate 7'b to prevent this leftward movement of the rotating shaft 1. This can be prevented by the elasticity of the spring plate, and the rotation of the rotating shaft 1 is supported while maintaining its normal position. The pad 4c is in preloaded contact with the rotating shaft 1 by means of the double structure 7c. Therefore, each pad 4a,
4b and 4c do not have unstable contact with the rotating shaft 1 as in the conventional case, and the possibility of fluttering or lockup is eliminated.

When the rotation of the rotating shaft 1 gradually increases to shift to steady rotation, a pressure gas film is formed between the rotating shaft and the pressure receiving surface of each pad, and the pressure of the gas film increases as the rotation increases. Then, the surface contact sliding between the rotating shaft and each pad gradually decreases, and the rotating shaft comes to be supported via a gas film, so that the rotational resistance of the rotating shaft is significantly reduced. During this time, the second pad assembly 3
In b, the double structure 7b corresponds to the increase in gas film pressure generated on the pressure receiving surface of the pad 4b.
The spring plates 7'b, 7''b of the third pad assembly 3c are moved backward, and the spring plates 7'c, 7 of the double structure 7c are similarly moved in proportion to the increase in gas film pressure in the third pad assembly 3c. A backward displacement of ``c'' is performed. Since the spring plate rigidity of the third pad assembly 3c is made smaller than that of the second pad assembly 3b, the double structure 7c will eventually come into contact with the stopper 8c with the gap Cr reduced. When the gas film pressure increases after this state, the third pad assembly 3c rigidly supports the rotating shaft 1 in exactly the same manner as the first pad assembly 3a. Even during the transition to the steady rotation, each pad is always pressed against the rotating shaft without slack through the gas film, so there is no chance of fluttering or lockup.

From the time when the rotary shaft 1 shifts to a high speed of steady rotation, the rotary shaft undergoes expansion due to engine heat and frictional heat due to operation, and expansion due to centrifugal force, causing the shaft diameter to increase slightly. This thickening of the shaft diameter temporarily reduces the clearance between the rotating shaft and each pad, but on the other hand, this reduction in clearance increases the pressure of the gas film, and in the case of the first pad assembly 3a, Provides effective floating support for the rotating shaft, and the second pad
In the assembly 3b, the retraction of the spring plate is automatically controlled so as to form an appropriate film thickness by balancing the increase in gas film pressure at the relevant portion and the receding curve of the double structure spring plate. In the third pad assembly 3c, at the time of this rotational shaft expansion, the double structure 7c has already retreated to the stopper 8c, and the gap between the rotational shaft 1 and the pad 4c is smaller than that at the start of the rotational shaft by the amount Cr. (To explain this Cr in detail, it is the amount of clearance that can accommodate this expansion in anticipation of the amount of radial expansion of the rotating shaft.) Since the pad 4c is large enough to support the rotating shaft 1 at the optimal position. be.

It was mentioned that even in conventional bearings, the supporting state is quiet and stable when the rotating shaft rotates at high speed, but the device of the present invention is supported by a spring plate that satisfies the above-mentioned conditions of the conventional bearing. By preventing the pivot shaft from collapsing and inclining, and by taking reasonable measures to prevent expansion in the radial direction of the rotating shaft, it is possible to obtain a stable support that is quieter than conventional ones. In addition, in case of sudden abnormal vibration of the rotating shaft 1,
The stoppers 8b, 8c in the second and third pad assemblies 3b, 3c stubbornly prevent the pivots 5b, 5c from retreating beyond the elasticity of their respective spring plates, and effectively prevent the above-mentioned abnormal deflection of the rotating shaft. It is something.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the main parts of a conventional pivot pad bearing, Figure 2 is a sectional view taken along the - line in Figure 1,
FIG. 3 is a sectional view of essential parts showing an embodiment of the present invention. 1: Rotating shaft, 2: Bearing casing, 3a: First
Pad assembly, 3b: Second pad assembly, 3c: Third pad assembly, 4a, 4
b, 4c: pivot pad, 5a, 5b, 5c:
Pivot, 6a, 6b, 6c: Support block, 7
b: Double structure (high and low rigid spring plates 7'
b, 7″b), 7c: Double structure (consisting of low rigidity spring plates 7′c, 7″c), 8b, 8c: Stopper, Cr: Clearance.

Claims (1)

[Scope of utility model registration request] In a bearing in which the three parts of the circumference of the rotating shaft are supported by three pad assemblies each comprising a support block fixed to the bearing casing and a pivot pad in direct contact with the rotating shaft, the lower part of the rotating shaft is The first pad assembly is integrally fixed to a support block so that its pivot axis can be adjusted forward and backward toward the rotating shaft, and is located on the leading side of the first pad assembly relative to the rotational direction of the rotating shaft. The second pad assembly in the arrangement has its pivot axis fixed perpendicularly to a double structure of high and low rigid spring plates attached to the support block, and A stopper whose clearance can be adjusted with respect to the fixed outer part is provided on the support block, and a third pad assembly disposed on the trailing side of the first pad assembly in relation to the rotational direction of the rotating shaft is provided with a stopper that is adjustable in clearance from the outside of the fixed pad assembly. The axis of the pivot is fixed perpendicularly to a double structure of low-rigidity spring plates attached to a support block,
A pivot pad bearing characterized in that the support block is provided with a stopper whose clearance can be adjusted with respect to the orthogonally fixed outer side of the double structure.