JPS63243522A - Thrust bearing construction relative to rotating shaft - Google Patents

Abstract

PURPOSE:To support a rotating shaft with less rotating resistance in case of a small load and with better durability in case of a large load, by forming a clearance between the first thrust bearing and the rotating shaft by a spring force. CONSTITUTION:When a load placed on the upper surface of a driven rotating disc 2 is smaller than a set value, shrinkage of a spring 7 is small and a clearance is formed between a thrust bearing 9 and the lower surface of the driven rotating disc 2. Therefore, the driven rotating disc 2 is supported by a bearing 6 only and with less rotating friction resistance. When a load acting on the driven rotating disc 2 is larger than the set value, thee driven rotating disc 2 is also supported on the thrust bearing portion 9 by shrinking the spring 7, and then, the durability can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for supporting a rotating shaft that rotates while being subjected to a load in the thrust direction using a thrust bearing with low frictional resistance. This invention relates to a thrust bearing structure for a rotating shaft that can be supported with good durability even when a large load is applied.

[Conventional technology]

When supporting a rotating shaft with low frictional resistance, it is common practice to install a small-diameter thrust bearing with the lowest possible rolling friction coefficient to support the rotating shaft. Generally speaking, as the thrust bearing is configured with a smaller diameter bearing, such as a so-called miniature bearing, the allowable pressure limit for the thrust load of the thrust bearing tends to decrease, and the thrust acting on the rotating shaft tends to decrease. When the load increases and exceeds the allowable pressure limit of the thrust bearing, the thrust bearing wears or deforms, increasing the rotational resistance of the rotating shaft and shortening its life.

On the other hand, it is conceivable to configure the thrust bearing with a large diameter bearing that has a large allowable pressure, but it is normal that the rolling friction coefficient becomes relatively large as the bearing is configured with a large diameter bearing. Therefore, there is a drawback that the rotational resistance of the rotating shaft increases.

Therefore, for example, in precision instruments and measurement fields such as viscosity measurement, where the rotational resistance of the rotating shaft is minimized and the load acting on the rotating shaft fluctuates, conventionally, the load acting on the rotating shaft is small. In some cases, the rotating shaft is supported via a small-diameter hair ring with a small friction coefficient, and in cases where the load acting on the rotating shaft is large, the rotating shaft is supported via a large-diameter thrust bearing with a large friction coefficient but with a large allowable pressure. The rotary shaft was supported by the rotary shaft.

[Problem that the invention seeks to solve]

In this way, in the past, thrust bearing structures for rotating shafts were prepared with large diameter ones and small diameter ones, and the bearing structure had to be changed depending on the magnitude of the thrust direction load acting on the rotating shaft. However, the disadvantage is that the replacement work is troublesome.

The present invention has been made focusing on the above-mentioned circumstances, and
When the load in the thrust direction acting on the rotating shaft is small, the rotating shaft can be supported with low rotational resistance, and when the load is large, the rotating shaft can be supported with good durability, and the rotating shaft can be supported automatically without replacing the bearing. The object of the present invention is to provide a thrust bearing structure for a rotating shaft that can respond to load fluctuations.

[Means for solving problems]

That is, the features and configuration of the present invention are such that the rotating shaft is slidably attached to the first thrust bearing in the axial direction, and
A second thrust bearing having a smaller diameter than the thrust bearing is provided to be able to slide integrally with the rotating shaft, and a spring is provided that biases the second thrust bearing in a direction in which the rotating shaft is separated from the first thrust bearing. Its functions and effects are as follows.

[For production]

When the load acting on the rotating shaft is less than the set value, a gap is formed between the first thrust bearing and the rotating shaft due to the biasing force of the spring, and the rotating shaft is connected to the first thrust bearing. Since the rotary shaft can be supported only by the second thrust bearing, which has a relatively small diameter, the rotating shaft can be supported by the second thrust bearing, which has a relatively small coefficient of rolling friction, with little rotational resistance. Furthermore, when a large load greater than the biasing force of the spring is applied to the rotating shaft, the spring expands and contracts so that the rotating shaft is supported by the first thrust bearing, which has a larger diameter than the second thrust bearing. Because you can
It is possible to prevent the second thrust bearing from being subject to wear and deformation due to a load that exceeds its design allowable pressure.
Thrust bearings can be used for long-term use without changing the friction coefficient.

〔Effect of the invention〕

As a result, even when the load acting on the rotating shaft fluctuates,
There is no need to replace large and small thrust bearings according to the load as in the past, and it is possible to automatically switch between reducing the friction coefficient and increasing the allowable pressure depending on the load. This has made it possible to reduce frictional resistance, improve durability, and eliminate the need for attachment and replacement work, improving workability.

In particular, this thrust bearing structure can be used, for example, in a rotational viscometer that measures the viscosity of glass over a wide range by varying the load acting on the rotating shaft and changing the coefficient of friction at the rotating shaft. When applied, the viscosity of glass can be measured with simple operations when measuring the viscosity of various glasses with greatly different viscosities.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment will be described based on the drawings, in which the bearing structure for a rotating shaft according to the present invention is applied to a rotational viscometer for measuring the melt viscosity of glass.

First, to explain the general configuration of the rotational viscometer, as shown in Fig. 3, there is a rotating rod (5) that is rotated at a constant speed from the lower surface of a servo motor (11) installed on a mounting base (10).
is vertically installed, and a disc-shaped drive-side rotating disk (1) is attached to the lower end of the rotating rod (5) so as to rotate at the same speed as the rotating rod (5). Below the drive-side rotary disk (1), a driven-side rotary disk (2) as a rotating shaft according to the present invention that pivotally supports the drive-side rotary disk (1) is mounted on the mounting base (10). It is arranged horizontally rotatably on a fixed frame (19), and due to the friction between the driving side rotary disk (1) and the driven side rotary disk (2), the rotational driving force from the driving side rotary disk (1) is rotated on the driven side. Board (
2) It is designed to be transmitted to the side. A connecting portion (2
A connecting rod (21) is connected to the connecting rod (2), and a rotor (3) is removably connected to the lower end of the connecting rod (2).

A reflective surface (22) is fixed to the outer periphery of the connecting rod (21), and consists of a non-contact tachometer (4a) and a photoelectric prong (4b) arranged near the reflective surface (22). The measuring device (4) makes it possible to measure the rotational speed of the connecting rod (21).

In the figure, (24) is a flexible joint part, (25) is a bearing holding part fixed to the mounting base (10), and (26) is a flexible joint part.
is a container in which the molten glass (8) is placed, and (30) is a tension gauge for measuring the frictional force generated between the two rotary disks (1) and (2).

Next, the structure of the +'+if drive side rotary disk (1) and driven side rotary disk (2) will be explained in detail.As shown in FIG. 1
) has a hexagonal fitting hole (12) in a plan view.
A connecting portion (13) having a recessed portion is integrally provided,
A fitting part (14) having a hexagonal cross section formed at the lower end of the rotating shaft (5) is fitted into the fitting hole (12) so as to be movable up and down. There is a protrusion (3I) on the top surface of the drive side rotary disk (1).
is provided protrudingly, and a weight (23) having a two-split construction is placed on top of the weight (23), and a recess (3) formed in the lower surface of the weight (23) is placed on top of the weight (23).
By engaging the protrusion (31) in 2), it is possible to prevent the weight (23) from falling during high-speed rotation. The body (29) can be attached.

As shown in FIGS. 1 and 2, the driven side rotary plate (2) is formed into a substantially disk shape, and a ring-shaped protrusion (16) is provided around the upper surface of the driven side rotary plate (2). It is provided in a protruding manner and is configured to have a predetermined coefficient of friction with the contact surface (15) on the lower surface of the drive-side rotary disk (1). A thrust bearing (9) as a first thrust bearing and a second thrust bearing are provided below the driven side rotary disk (2) to support the driven side rotary disk (2) with low frictional resistance. radial bearings (6) are respectively disposed, and a donut-shaped fixing frame (work 9) in a plan view for accommodating these is placed and fixed on the mounting base (10), and the bearings (6)
) and the driven side rotary disk (2) via the thrust bearing (9).
By rotatably supporting the rotor on the mounting base (10), the rotational drive resistance of the driven rotary disk (2) can be reduced.

An outer cylinder (27) and an inner cylinder (2) are provided on the upper surface of the fixed frame (19).
8) are respectively erected, and the connecting part (20) of the driven side rotary disk (2) is inserted inside the inner cylinder (28), and this connecting part (20) and the inner cylinder (28) A holder (18) that holds the bearing (6) and a spring (7) formed of a compression coil spring is disposed between the two and is movable up and down. The holder (18) is urged upward by the spring (7), and the upper end surface of the bearing (6) abuts and supports the lower surface of the stepped portion (20a) formed at the upper portion of the connecting portion (20). At the same time, the bearing (6) prevents the connecting portion (20) from rotating eccentrically.

Further, the thrust bearing (9) is disposed between the inner cylinder (28) and the outer cylinder (27), and the load does not act on the upper surface of the driven side rotary disk (2) or is lower than a set value. When a load of
The urging force of this bearing (6) is set so that a gap is formed between it and the lower surface. The bearing (6
) is also called a miniature bearing, and is constructed with a smaller diameter than the thrust bearing (9). Therefore, this bearing (6) has a smaller coefficient of friction in the thrust direction than the thrust bearing (9). On the other hand, the thrust bearing (9) is designed to have a larger allowable pressure against the load in the thrust direction than the bearing (6).

The connecting portion (20) of the driven side rotary disk (2) has a recess (2) into which the engaging portion (21a) of the connecting rod (21) is inserted.
0a), and the bearing holding portion (25) of the connecting rod (21) connected to the driven side rotary disk (2) is provided with a bearing holding portion (25) for transmitting the rotational force of the connecting rod (21) to the rotor (3). ,
In addition, there is a flexible mechanism (2) that allows vertical movement of the connecting rod (21).
9), which connects the rotor (3) and the connecting rod (2).
Loads such as 1) are prevented from acting on the driven side rotary disk (2), and thermal expansion and contraction of the glass (8) are prevented from acting on the driven side rotary disk (2).

Next, a case will be described in which the viscosity of molten glass is measured using the rotational viscometer having the above configuration.

As shown in Fig. 1, molten glass (8) is placed in a container (26), and the motor (11) is driven while the glass (8) is immersed in the glass (8) by a predetermined dimension at the bottom of the rotor (3). . Then, the drive-side rotary disk (1) rotates at the set speed, and since the drive-side rotary disk (1) is in pressure contact with the upper surface of the driven-side rotary disk (2) with the set load, the driven-side rotary disk ( 2) is the friction surface ([7) and the drive side rotary disk (1)
The friction with the contact surface (15) causes the driven rotation. Here, if no rotational resistance is applied to the No. 1111 rotor (3), the driven side rotary disk (2) will have almost the same speed as the driving side rotary disk (1) even if the frictional force is small. However, when the rotor (3) is subject to viscous resistance from the glass (8), the rotation occurs between the driven side rotary disk (2) and the driving side rotary disk (1) according to the viscous resistance. As a result, the rotational speed of the rotor (3) decreases compared to the rotational speed of the rotating shaft (5). The rotational speed of the rotor (3) has a correlation with the viscous resistance of the glass (8) and the frictional force between both rotating discs (1) and (2), so the frictional force can be measured by the tension gauge (
30) to measure the rotational speed of the rotor (3) using a measuring device (
By measuring in step 4), the viscosity of the glass (8) can be calculated. In addition, when measuring the viscosity of highly viscous glass (8), the rotational speed of the rotor (3) decreases or does not rotate due to the large viscous resistance, resulting in an error in the measured viscosity or when the viscosity cannot be measured. However, in this case, a two-part weight (23) as shown in Figure 2 is placed on the top of the drive side rotary disk (1), and a weight (23) divided into two parts as shown in Fig. 2 is placed on the friction surface (17) of the driven side rotary disk (2). By increasing the normal force acting and increasing the frictional force between the rotating discs (1) and (2), the rotor (3) rotates with the viscous resistance of the glass (8) and the frictional force balanced. This makes it possible to measure the viscosity of highly viscous glass without any problems.

Here, when the combined load of the drive-side rotary disk (1) and the weight (23) etc. placed on the upper surface of the driven-side rotary disk (2) is less than a set value, the degree of expansion and contraction of the spring (7) is determined. is small, and a gap is formed between the thrust bearing (9) and the lower surface of the driven side rotary disk (2) as shown in Figure 1 (a). Since the shaft is supported only by the bearing (6), the driven side rotary disk (2) can be supported with relatively little rotational frictional resistance.

Also, as mentioned above, a weight (
23) and the load acting on the driven side rotary plate (2) exceeds the set value, the spring (7) contracts due to this load as shown in Figure 1 (b). The thrust bearing (9) part now also pivotally supports the driven side rotary disk (2), and by supporting the load that exceeds the allowable pressure of the bearing (6) with the thrust bearing (9) part, the This prevents large pressure from acting on the bearing (6), and prevents the bearing (6) from wearing out, changing its friction coefficient, and shortening its lifespan. still,
When the driven rotary disk (2) is supported by the thrust bearing (9), there is a space between the holder (18) and the fixed frame (19), and the bearing (6) is supported by its allowable pressure. It is pressed against the lower surface of the driven side rotary disk (2) with an elastic contact force within a range.

[Another example]

A driving-side rotary disk (1) and a driven-side rotary disk (2) are arranged on the left and right, and the driving-side rotary disk (1) is biased toward the driven-side rotary disk (2) by a spring. It may be configured to change the forces. Further, although the above embodiments have been described with respect to a glass viscometer, the present invention can also be applied to the slus I/bearing structure of precision instruments and other measuring devices.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

The drawings show an embodiment of the thrust bearing structure for the rotating shaft according to the present invention, and FIG. FIG. 2 is an exploded perspective view of the main part, and FIG. 3 is a schematic side view of the rotational viscometer. (2)...Rotating shaft, (6)...Second thrust bearing, (7)...Spring, (9)...
...First thrust bearing.

Claims (1)

[Claims] A rotating shaft (2) is attached to the first thrust bearing (9) so as to be slidable in the axial direction, and a second thrust bearing (6) having a smaller diameter than the first thrust bearing (9) is attached to the rotating shaft (9). 2)
a rotating shaft provided with a spring (7) that is slidably integral with the rotating shaft and biases the second thrust bearing (6) in a direction in which the rotating shaft (2) separates from the first thrust bearing (9); Thrust bearing structure against.