JPH0135207B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a journal bearing, and particularly to a hydrodynamic journal bearing.

[Background of the invention]

For example, as described in U.S. Pat. No. 3,497,276, a conventional hydrodynamic journal bearing has pads 3a and 3b, it is supported without contact. Generally, the pad 3a has a fixed pivot 4a.
The pads 3b are supported in point contact with the top 5 of the movable pivot 4b and the bottom 7 of the respective pad groove 6. The fixed pivot 4a is fixed to the bearing housing 8. The movable pivot 4b is supported by an elastic coil spring 10 in order to move within the hole 9 in the housing 8 in the radial direction of the rotating body.
One end of the coil spring 10 is restrained by a stroke adjustment screw 12 having a threaded portion that fits into the guide thread groove 11 of the housing 8 . The hole 9 has a step 13, and the movable pivot 4b is restrained by contacting the step 13, so that the movable pivot 4b does not approach the pad 3b by a predetermined distance or more.

When the rotating shaft 2 is stopped, the coil spring 10
The movable pivot 4b pushed toward the rotating shaft by the hole 9
The top 5 of the movable pivot 4b and the bottom 7 of the pad 3b are not in contact with each other. That is, the pad 3b is connected to the rotating shaft 2 and the movable pivot 4.
There is a play between the parts b by the amount of non-contact. This backlash occurs when the rotating shaft 2 starts to rotate.
This is to minimize the frictional force on the contact surfaces with a and 3b, so that the rotating shaft can start rotating with a small torque.
When the rotating shaft starts to rotate, the gas or liquid in the space 14 forms a thin film between the outer surface of the rotating shaft and the three pad surfaces, and the pad 3b floats due to the rigidity of the thin film. As the rotation speed of the rotating shaft increases,
The rigidity of the thin film increases, and the flying height of the pad 3b also increases. When the bottom surface 7 of the groove 6 of the pad 3b comes into contact with the top 5 of the movable pivot 4b, the flying height of the pad 3b, that is, the radial movement distance is reduced by the coil spring 1.
controlled by a stiffness of 0. At this time, the stiffness 11 of the thin film matches the stiffness of the coil spring 10. In order to rotate the rotating shaft 2 stably at high speed, it is necessary to select the rigidity of the thin film correctly. That is, the rigidity, or preload, of the coil spring 10 must be precisely and correctly adjusted. The rigidity of the coil spring 10 is adjusted by adjusting the stroke of the coil spring 10 using the stroke adjustment screw 12, but in conventional bearings, the final step is to combine the bearing with a rotating shaft, a pad, a fixed and movable pivot, a coil spring, and a stroke adjustment screw. Adjust the stroke of the coil spring with . Therefore, to adjust the coil spring, before combining the spring constant of the coil spring, first measure it accurately using a load meter, and then set the stroke precisely based on this result. There is a problem that requires precision work in the process.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a journal bearing in which the preload of the journal bearing can be precisely adjusted independently before assembly of the bearing, thereby facilitating assembly work.

[Summary of the invention]

The present invention adds a mechanism for restraining the elastic body that generates the preload as a means to finely adjust the preload applied to the pivot without using the pivot. This allows for precise adjustment.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 1 shows a sectional view around the movable pivot, and the two fixed pivots not shown in the figure are similar to the structure of the conventional journal bearing shown in FIG. The support portion of the rotating shaft 17 of the rotating body supported by the movable pivot 15 via the pad 16 is as follows:
A coil spring 18 that is an elastic body;
A spring stopper 19 of the movable body restrained at both ends of the body, a spring fixing screw 20 of the restraint body, and a screwdriver groove 2 which is another restraint body for adjusting the preload by the coil spring 18.
1 load adjustment screw 22, movable pivot insertion hole 24 provided in the housing 23, screw groove 2 on the top
5, the spring fixing screw 20 is firmly fixed to the housing 23 of the bearing body with a nut 26.

The rigidity, or preload, of the coil spring 18, which is an elastic body, is adjusted by an external adjuster separate from the journal bearing, the configuration of which is shown in FIG. A shell 2 has a loading means that is a combination of a coil spring 18, a spring stop 19, a spring fixing screw 20, and a load adjustment screw 22, and has, for example, a semiconductor type load sensor 27 installed at the bottom.
Attach to 8. The load applied to the load sensor 27 is read by a load meter 30 connected with a lead wire 29.

In the state shown in Figure 2, tighten the spring fixing screw 20 to shell 2.
8, the coil spring 18 is restrained by the spring stopper 19 and its rigidity increases. The load is transmitted to the load sensor 27 in contact with the spring stop 19, and its value is displayed on the load meter 30. In this way, the spring fixing screw 20 is screwed in to a predetermined load. When the predetermined load is reached, the load adjustment screw 22 is in a non-contact state with the spring stopper 19, but when the tip of the screwdriver is inserted into the screwdriver groove 21, the screwdriver is turned until it comes into contact with the spring stopper 19. Move it upward. After coming into contact with the spring stopper 19, the threaded portion 31 is fixed with an adhesive or the like to restrict the extension length of the coil spring 18 to prevent it from being screwed in. This completes the precise adjustment of the preload generated by the coil spring 18, and
Remove the entire spring fixing screw 20 including 8 from the shell 28. According to this adjustment, there is no need to measure the spring constant of the coil spring 18 and the amount of contraction of the coil spring 18, so compared to the conventional technology in which the preload is set based on the amount of contraction of the coil spring 18, errors in measuring the amount of contraction are included. can be adjusted more accurately.

As for assembly around the movable pivot, after the rotating shaft 17, pad 16, and movable pivot 15 are assembled, the spring fixing screw 20 containing the coil spring 18 is attached to the thread groove 25 of the housing 23. rotating shaft 17,
Pad 16, movable pivot 15 and spring stop 1
9 are in contact with each other until the spring fixing screws 20 are in contact with each other.
For example, if the screw has a pitch of 0.5 mm, then turn it 1/50 turn in the opposite direction to apply a 10 μm screw 32 between the movable pivot 15 and the spring stopper 19, and then tighten the spring fixing screw 20 onto the housing 23. Fix it with nut 26. The spring fixing screw 20 may be fixed by fixing the threaded portion with an adhesive. This completes the assembly around the movable pivot. In other words, this work uses precision tools and does not require precision work.

Since there is a gap 32, the rotating shaft 17 rotates with a small torque at the initial stage of rotation. As the rotational speed increases, the pad 16 floats up and the movable pivot 15 comes into contact with the spring stop 19. After this, when the rotational speed further increases, the movable pivot 15 will stop the spring stop 1.
9 is pushed up, that is, the coil spring 18 is moved in the direction of contracting. At this time, the coil spring 18 applies a precisely adjusted preload to the movable pivot 15, and can support the pad 16 while applying the preload. That is, according to this embodiment, the preload generated by the coil spring 18 is precisely adjusted in one step before assembling the movable journal bearing, and there is no need for precision work using precision tools etc. when assembling the bearing. This has the effect that assembly work can be done easily and in a short time.

〔Effect of the invention〕

According to the present invention, the preload applied to the movable pivot that supports the rotating shaft is adjusted in one precision operation by separating the rotating shaft and the pivot.
Assembling the movable journal bearing does not require precision work, so it has the advantage of being easy to assemble.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the surroundings of a movable pivot showing an embodiment of the journal bearing according to the present invention, FIG. 2 is a cross-sectional view showing the preload precision adjustment state of the journal bearing of FIG. 1, and FIG. 1 is a cross-sectional view showing an example of a conventional journal bearing. 15...Movable pivot, 16...Pad, 17
... Rotating shaft, 18 ... Coil spring, 19 ... Spring stop, 20 ... Spring fixing screw, 22 ... Load adjustment screw, 32 ... Between.

Claims (1)

[Claims] 1. A rotating body and a plurality of pads supporting the rotating body in the radial direction, at least one of the pads supporting the rotating body so as to be movable in the radial direction. In a journal bearing comprising a movable pivot and a bearing body supporting the movable pivot, a load means having one end fixed to the bearing body and having an adjusted load is provided between the movable pivot and the bearing body, A journal bearing characterized in that a gap is provided between the load means and the movable pivot so that the load does not act on the movable pivot when the body is stopped. 2. The loading means is composed of a restraining body that restrains the elastic body and the movable body in the direction of extension of the elastic body, and a movable body that does not restrain the direction of contraction of the elastic body, and the movable pivot is configured such that the movable pivot extends in the radial direction of the rotary body. The journal according to claim 1, wherein when the moving body moves toward the elastic body, the moving body comes into contact with the movable pivot, and a load due to the contraction of the elastic body acts on the movable pivot. bearing.