JPH11159533A - Hydro static bearing support guide roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify structure and reduce a cost through reduction of the number of constituting parts, and besides to provide stable rotation performance through suppression of the occurrence of air hammer phenomenon, to reduce weight and an inertial moment, and to prevent the occurrence of seizure. SOLUTION: A small diametrical shaft part of a fixed shaft 1 is rendered longer than a roller 7 by length equivalent to thrust bearing gaps 6 and a shaft end part is finished to be smooth and a thrust disc 3 is attached to an end face. A slight chamfering is formed at the edge of the small part of the fixed shaft 1 and the roller 7 is formed of a porous material. Surface treatment of some of impregnation with a metal or resin to prevent leakage of compressed air, plating, coating, and thermal spraying or the joint use thereof is applied on the outer peripheral surface thereof. Further, exhaust passages 9 and 10 communicated with an external part are arranged at a boundary part between a radial bearing gap 5 and a thrust bearing gap 6. Further, the roller 7 is manufactured by using carbon or surface treatment consisting mainly of molybdenum dioxide is applied on the stepped end face of the fixed shaft 1, the end face, positioned facing the stepped end face of the fixed shaft 1, of the thrust disc 3, and the outer peripheral surface of the small shaft part of the fixed shaft 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a guide roller for supporting a hydrostatic bearing used in a facility for manufacturing magnetic tapes, film capacitors, and the like.

[0002]

2. Description of the Related Art As shown in FIG. 3, a guide roller supporting a hydrostatic bearing is opposed to a small-diameter shaft portion of a fixed shaft 11 having a stepped structure having an air supply passage 12 at an interval in the axial direction. Thrust plates 13 and 14 are provided.
A cylindrical roller 16 is inserted into a circumferential gap 15 formed by the opposed end face of the fixed shaft 4 and the outer peripheral surface of the small-diameter shaft portion of the fixed shaft 11.
Between the inner peripheral surface of the roller 16 and the outer peripheral surface of the small-diameter shaft portion of the fixed shaft 11 and both end surfaces of the roller 16 and the thrust plates 13, 1.
A radial bearing gap 17 and a thrust bearing gap 18 are provided and fitted between the opposed end faces, respectively, to communicate between the radial bearing gap 17 and the air supply passage 12 via the nozzle 19, while the thrust bearing gap 18 is provided. And air supply passage 12
Between the air supply hole 20, the circumferential air supply passage 21 and the nozzle 2
2, the compressed air introduced into the air supply passage 12 of the fixed shaft 11 is supplied to the radial bearing gap 17 through the nozzle 19, and at the same time, the air supply hole 20 and the circumferential air supply passage 21 The roller 16 is also supplied to the thrust bearing gap 18 via the nozzle 22 to rotatably support the roller 16 with respect to the fixed shaft 11 in a non-contact manner. The compressed air supplied to the radial bearing gap 17 is supplied to the exhaust passage 2.
3, and the compressed air supplied to the thrust bearing gap 18 is directly discharged to the outside.

In this type of guide roller, there is a demand for a simplified structure and a structure that requires as little air consumption as possible. A guide roller having a structure shown in FIG. 4 is considered as a guide roller for reducing the amount.

The guide roller has an air supply passage 32 therein.
A thrust plate 33 is provided on a small-diameter shaft portion of a fixed shaft 31 having a stepped structure having a stepped structure and opposed to a step end surface of the fixed shaft 31 at an interval in the axial direction, and the thrust plate 33 and the fixed shaft 31 are provided.
A cylindrical roller 35 is provided between the inner peripheral surface of the roller 35 and the outer peripheral surface of the small-diameter shaft portion of the fixed shaft 31 in the circumferential gap portion 34 formed by the step end surface and the outer peripheral surface of the small-diameter shaft portion. Roller 3
5, the end face of the fixed shaft 31 and the thrust plate 33
A radial bearing gap 36 and a thrust bearing gap 37 are provided and fitted between the stepped end face and the end face of the fixed shaft 31, respectively, and the radial bearing gap 36 and the air supply passage 32 are fitted.
Are communicated via a nozzle 38.

In the above guide roller, the fixed shaft 3
The compressed air introduced into the first air supply passage 32 is
The roller 35 is rotatably supported by the fixed shaft 31 in a non-contact manner by supplying the roller 35 to the radial bearing gap 36 and then to the thrust bearing gap 37.

In the above structure, the number of components can be reduced, so that the structure can be simplified, and the supply of compressed air to the radial bearing gap 36 also serves to supply compressed air to the thrust bearing gap 37. Therefore, there is an advantage that the consumption of compressed air can be reduced.

[0007]

By the way, in the guide roller having the structure shown in FIG. 4, the portion forming the hydrostatic air bearing needs to be processed with high precision, and the clearance between the two bearings 36, 37 is required for the convenience of assembly. The clearance 39 and the chamfer 40 are provided at the boundary, and when compressed air is supplied to the two bearing gaps 36, 37, an air pocket is formed at the boundary between the two bearing gaps 36, 37.

In the case of the static pressure air bearing, if the air pocket exists as described above, an air hammer phenomenon may occur depending on the size of the air pocket, and stable rotation performance may not be expected. In particular, when the roller is moved by the thrust force and the clearance of one of the thrust bearings is reduced, the air hammer phenomenon is more likely to occur. Therefore, every time the size of the guide roller is changed, a design change or a preliminary experiment is required.

Further, when an excessive load exceeding the load capacity of the hydrostatic air bearing is applied during operation, such as an impact load, or when the supply of compressed air is interrupted during operation for some reason,
When the rotating roller 35 comes into contact with the fixed shaft 31 and this is repeated, seizure may occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and the number of components can be reduced, the structure can be simplified, the cost can be reduced, and the occurrence of the air hammer phenomenon can be suppressed to be stable. It is an object of the present invention to provide a guide roller that supports a hydrostatic bearing, which can provide rotation performance, is lightweight, has a low moment of inertia, and does not easily seize.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a small-diameter shaft portion having a stepped structure having an air supply passage therein, and a small-diameter shaft portion which is axially aligned with a step end face of the fixed shaft. An opposed thrust plate is provided at an interval, and a cylindrical roller is provided in a circumferential gap formed between the thrust plate and the stepped end surface of the fixed shaft and the outer peripheral surface of the small-diameter shaft. Radial bearing clearance and thrust bearing clearance between the surface and the outer peripheral surface of the small-diameter shaft portion of the fixed shaft, and between both end surfaces of the guide roller and the step end surface of the fixed shaft and the end surface of the thrust plate facing the step end surface of the fixed shaft, respectively. In the guide roller supporting the hydrostatic bearing in which the air supply passage is communicated with the radial bearing gap, the small-diameter shaft portion of the fixed shaft has a length corresponding to a thrust bearing gap on both sides of the roller. It is formed long and its shaft end is smoothed. Along with attaching a thrust plate to the end surface, the roller was made of a porous material, and metal or resin impregnation, plating, coating, and thermal spraying were used together or each so that compressed air did not leak to the outer peripheral surface. It is characterized by surface treatment.

A second invention of the present invention is characterized in that the roller is made of porous carbon.

In a third aspect of the present invention, molybdenum disulfide is mainly provided on the step end surface of the fixed shaft, the end surface of the thrust plate facing the step end surface of the fixed shaft, and the small diameter shaft outer peripheral surface of the fixed shaft. It is characterized by having been subjected to a surface treatment as a component.

A fourth invention of the present invention is characterized in that an exhaust passage communicating with the outside is provided at a boundary between the radial bearing gap and the thrust bearing gap.

[0015]

Embodiments of the present invention will be described below.

FIG. 1 shows a first embodiment of the present invention. A guide roller according to this embodiment includes a fixed shaft 1 having a stepped structure having an air supply passage 2 therein, and a fixed shaft 1 having the stepped structure. A thrust plate 3 provided on the small-diameter shaft portion so as to face the stepped end surface of the fixed shaft 1 at an axial interval, and a stepped end surface of the thrust plate 3 and the fixed shaft 1 and an outer peripheral surface of the small-diameter shaft portion. Between the inner peripheral surface and the outer peripheral surface of the small-diameter shaft portion of the fixed shaft 1, the both end surfaces thereof, the step end surface of the fixed shaft 1, and the fixed shaft 1 of the thrust plate 3. The main configuration is a cylindrical roller 7 fitted with a radial bearing gap 5 and a thrust bearing gap 6 provided between the stepped end face and the end face facing the same.

The fixed shaft 1 is formed such that its small-diameter shaft portion is longer than the roller 7 by a length corresponding to the thrust bearing gap 6 on both sides, and finishes the end portion of the small-diameter shaft portion smoothly to form a thrust plate 3 on the end surface. Installed.

A nozzle 8 penetrating in the radial direction is provided on the small diameter shaft portion of the fixed shaft 1, and the nozzle 8 communicates the air supply passage 2 with the radial bearing gap 5.

An exhaust passage 9 is provided in the large-diameter shaft portion of the fixed shaft 1, and the exhaust passage 9 communicates the outside and the corner where the end face of the step portion and the outer peripheral surface of the small-diameter shaft portion intersect.

The roller 7 is made of a porous material. The roller 7 is provided with a metal or resin impregnated layer 7a on the outer peripheral surface thereof so that compressed air does not leak, and the surface of the impregnated layer 7a is subjected to a surface treatment such as plating. ing.

A chamfer 7b is provided at the corner where the inner peripheral surface and both end surfaces of the roller 7 intersect. The chamfer 7b is impregnated with metal or resin so that compressed air does not leak, or the surface is plated. And other surface treatments.

An exhaust passage 10 is provided in the thrust plate 3, and the end surface of the thrust shaft 3 is fixed to the fixed shaft 1 in the exhaust passage 10.
The outside of the small diameter shaft portion communicates with a corner where the outer peripheral surface intersects.

In this embodiment, the supply passage 2 of the fixed shaft 1
Is supplied to the radial bearing gap 5 via the nozzle 8 and then passed through the hole in the roller 7 and supplied to the thrust bearing gap 6, whereby the roller 7 is fixed to the fixed shaft 1. It is rotatably supported in a non-contact manner. The remaining compressed air supplied to the radial bearing gap 5 through the holes in the roller 7 and supplied to the thrust bearing gap 6 is discharged outside through the exhaust passages 9 and 10 on both sides. .

According to the guide roller of this embodiment, the small diameter shaft portion of the fixed shaft 1 is formed longer than the roller 7 by the length corresponding to the thrust bearing gap 6 on both sides, and the end of the small diameter shaft portion is made smooth. By finishing and attaching the thrust plate 3 to the end face, the number of components is small, the structure can be simplified, and the cost can be reduced.

The roller 7 is made of a porous material, and the chamfer 7b provided at the corner where the outer peripheral surface and the inner peripheral surface intersect both end surfaces is impregnated with metal or resin so that compressed air does not leak. By applying a surface treatment such as plating to the surface, the compressed air supplied to the radial bearing gap 5 passes through the hole in the roller 7 and is supplied to the thrust bearing gap 6, so that the radial bearing gap 5 The supply of the compressed air to the thrust bearing gap 6 also serves to reduce the consumption of the compressed air.

Further, since the roller 7 is made of a porous material, the roller 7 is lightweight and has a low moment of inertia, so that a tape or the like that guides the roller 7 is unlikely to slip.

Further, since the fixed shaft 1 and the thrust plate 3 are provided with exhaust passages 9 and 10 communicating with the outside at the boundary between the radial bearing gap 5 and the thrust bearing gap 6, the compression supplied to the radial bearing gap 5 is provided. The remainder supplied to the thrust bearing gap 6 through the air hole in the roller 7 by air is discharged to the outside through the exhaust passages 9 and 10,
The air hammer phenomenon due to the air pocket at the boundary between the radial bearing gap 5 and the thrust bearing gap 6 on both sides can be eliminated, and stable rotation performance can be obtained.

FIG. 2 shows a second embodiment of the present invention. The basic structure is the same as that of the guide roller of the first embodiment shown in FIG. The difference is that in order to eliminate the seizure problem, the roller 7 is made of porous carbon,
The chromium plating layer 7c is provided on the outer peripheral surface so that compressed air does not leak and surface hardness is improved.

According to the guide roller of this embodiment, since the roller 7 is made of carbon having excellent seizure resistance, the contact resistance between the roller 7 and the fixed shaft 1 and the thrust plate 3 can be reduced. Even if an excessive load exceeding the load capacity of the hydrostatic air bearing, such as an impact load, is applied during operation, or if the supply of compressed air is interrupted during operation for some reason, the rotating roller 7 and the fixed shaft 1 and Seizure due to contact of the thrust plate 3 does not occur.

Further, since the chrome plating layer 7c is provided on the outer peripheral surface of the roller 7 made of carbon, the surface hardness of the roller 7 is improved, so that the roller 7 is hardly abraded against a film or the like.

In the second embodiment shown in FIG. 2, the roller 7 is made of carbon to prevent seizure.
Is made of carbon instead of carbon. The surface mainly composed of molybdenum disulfide on the end face of the fixed shaft 1, the end face of the thrust plate 3 opposed to the stepped end face of the fixed shaft 1, and the outer peripheral surface of the small diameter shaft portion of the fixed shaft 1. Even if the treatment is performed, the image sticking can be similarly prevented.

The present invention is not limited only to the above embodiment. For example, in addition to impregnating or plating with metal or resin to prevent the compressed air from leaking to the outer peripheral surface of the roller 7, coating is also performed. Or thermal spraying treatment, or each treatment can be used in combination.

[0033]

The present invention has the following effects.

Since the number of components can be reduced, the structure can be simplified, and the cost can be reduced.

Since the supply of compressed air to the radial bearing gap also serves as the supply of compressed air to the thrust bearing gap via the porous roller, the consumption of compressed air can be reduced.

Since the exhaust passage communicating with the outside is provided at the boundary between the radial bearing clearance and the bearing clearances on both sides, the occurrence of the air hammer phenomenon can be suppressed and stable rotation performance can be obtained.

Since the rollers are lightweight and have a low moment of inertia, slippage of the guiding tape or the like can be prevented.

The contact resistance between the roller, the fixed shaft and the thrust plate is reduced by manufacturing the roller from carbon or by including molybdenum disulfide on the surface of the fixed shaft and the thrust plate forming the hydrostatic air bearing. So
The problem of seizing due to the contact between the roller, the fixed shaft and the thrust plate does not occur.

Since the surface hardness of the outer peripheral surface of the roller made of carbon is improved by the chromium plating treatment, it is possible to prevent abrasion on the film or the like.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view showing a conventional example of a guide roller supporting a hydrostatic bearing.

FIG. 4 is a longitudinal sectional view showing another conventional example of a guide roller supporting a hydrostatic bearing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed shaft 2 Air supply passage 3 Thrust plate 4 Circular gap 5 Radial bearing clearance 6 Thrust bearing clearance 7 Roller 7a Impregnation layer 7b Chamfer 7c Chrome plating layer 8 Nozzle 9 Exhaust passage 10 Exhaust passage

Claims (4)

[Claims] 1. A small diameter shaft portion of a fixed shaft having a stepped structure having an air supply passage therein is provided with a thrust plate opposed to a step end face of the fixed shaft at an axial interval. A cylindrical roller is inserted into a circumferential gap formed by the step end surface of the shaft and the outer peripheral surface of the small-diameter shaft, between the inner peripheral surface of the roller and the outer peripheral surface of the small-diameter shaft portion of the fixed shaft, and a guide roller. The radial bearing gap and the thrust bearing gap are provided between both end faces of the fixed shaft and the stepped end face of the fixed shaft and the end face of the thrust plate opposed to the stepped end face, respectively. In the guide roller supporting the hydrostatic bearing which communicates the passage, the small-diameter shaft portion of the fixed shaft is formed to be longer than the roller by a length corresponding to the thrust bearing gap on both sides, and the shaft end is smoothed and finished on the end surface. Attach the thrust plate and And a metal or resin impregnation, plating, coating and thermal spraying or a surface treatment using a combination of each of them to prevent compressed air from leaking to the outer peripheral surface thereof. Guide roller supporting pressure bearing. 2. The guide roller of claim 1, wherein said roller is made of porous carbon. 3. A surface treatment mainly composed of molybdenum disulfide is applied to the stepped end surface of the fixed shaft, the end surface of the thrust plate facing the stepped end surface of the fixed shaft, and the small diameter shaft outer peripheral surface. The guide roller of claim 1, wherein the guide roller supports the hydrostatic bearing. 4. A guide roller for supporting a hydrostatic bearing according to claim 1, wherein an exhaust passage communicating with the outside is provided at a boundary between the radial bearing gap and the thrust bearing gap.