JPS5933766B2 - bearing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a bearing, and is characterized in that it is formed of a sintered alloy that integrally combines a journal bearing and a thrust bearing, and its purpose is to facilitate assembly. The present invention aims to provide a bearing mechanism with high usability.

Another object of the present invention is to provide a bearing structure suitable for the purpose of use.

The description of the drawings will be explained below, and then the contents of the present invention will be explained in detail.

1 to 4 illustrate the use of the sintered alloy bearing according to the present invention.

FIG. 1 shows a bearing mechanism of the present invention in which a cup-shaped sintered oil-impregnated bearing is arranged on the bearing opposite to the load side in an electric motor, and the thrust load is supported at the bottom of the bearing. 1 is a cup-shaped sintered alloy bearing having a cylindrical journal sliding part 21 and a thrust sliding part 22 forming a bottom sliding surface, 2 is a shaft, and 3 is a conventionally used load side bearing. This is a sintered oil-impregnated bearing.

The tip 4 on the side opposite to the load side of the shaft 2 is finished with a spherical or rounded surface, and the bottom sliding surface 23 of the cup-shaped sintered alloy bearing 1
24 is an air vent groove provided in the bearing 1, which has a spherical or circular depression corresponding to the shape of the tip of the shaft 2. Figure 2 shows a mechanism that holds the flywheel shaft, capstan shaft, reel shaft, and turntable shaft of a tape recorder, video coater, or record player, in which a cup-shaped sintered oil-impregnated bearing 1 is placed on the opposite side to the load side, and a thrust load is applied. FIG. 3 is a view showing a bearing mechanism of the present invention, which is characterized in that the bearing mechanism is supported at the bottom of a cup-shaped sintered bearing.

3 and 4 show other embodiments of the cup-shaped bearing in which a worm gear 5 and a retaining ring 6 are engaged with the shaft, respectively, and FIG. 5 shows the cup-shaped bearing in this embodiment. In the oblique perspective view, a notch 25 is provided between the journal sliding part 21 and the thrust sliding part 22.

FIG. 6 shows a mold structure for powder molding a cylindrical sintered bearing, and FIG. 6 shows a mold structure for powder molding a cup-shaped sintered bearing used in the present invention.

In Figures 6 and 7, 7 is the die, 8 is the upper punch, and 9 is the die.
10 indicates a lower punch, 10 indicates a core rod, and 11 indicates a powder compact. 8 and 9 show a method of receiving a thrust load in a conventional electric motor, and 12 and 13 indicate a washer and a ball bearing, respectively. FIG. 10 shows a shaft holding mechanism of a conventional direct drive type record player, where y is a journal bearing, and 14 is a polyslider for receiving two shaft ends, or a thrust bearing made of a hardened steel plate. Figure 11 is an assembly diagram of the bearing holder shown in Figure 10, a device for measuring the electrical continuity between the bearing and the shaft, 26 is the brush, 27
28 indicates the DC power supply, 28 indicates the observation using an oscilloscope, and RO indicates the bearing resistance.

12 and 13 show a conventional bearing holding mechanism in which a thrust load is received by a collar 14 or a collar and a thrust washer 15 on the end face of a cylindrical bearing. In the figure, 16 indicates a rubber sort, and 17 indicates a retaining ring.

As is well known, sintered oil-impregnated bearings are widely used as journal bearings and as bearings for various rotating shafts mainly in home appliances. In this case, if one shaft is placed horizontally and the load in the thrust direction (axial direction) is light, such as with an electric fan or ventilation fan, the collar 14 is directly applied to the end face as shown in Figure 12, or the collar 14 is directly applied to the shaft as shown in Figure 13. It is received by attaching a thrust washer 15 to the thrust washer.

2. When the thrust load is light for record players, tape recorders, and video coaters, but the shaft is placed vertically, the tip of the shaft is machined into a spherical surface as shown in Figure 10, and a self-lubricating material like a nylon plate is used. The spherical shaft end face is supported on a certain plate or a plate with good wear resistance such as hardened steel, or the shaft end with a depression is supported through a steel ball b as shown in Fig. 10B. .

In cases where the shaft is placed vertically and a large thrust load is applied, such as in a vertical ventilation fan or a motor for a user mixer, the thrust load is received by ball bearings (Figure 9).

In the case of 1 above, the accuracy of the end face run-out relative to the inner diameter of the sintered bearing is limited by the fitting accuracy of the powder molding die and the accuracy of the powder molding press. In addition to the limited machining accuracy and assembly accuracy of the collar and washer that slide on the bearing end face, the sliding contact of the bearing end face is poor, and the contact surface fluctuates with rotation. On the other hand, the lubricating oil seeping out onto the end sliding surface is shaken off by centrifugal force as the collar and washers rotate, causing the lubricating oil to rapidly scatter.

For the above two reasons, under the usage conditions as in case 1, noise generation and seizing wear always become a problem. In case 2, if a self-lubricating material such as nylon is used for the receiving plate on the shaft end surface, the contact area is small and the contact pressure is high due to the contact between a flat and curved surface, which may cause creep of the receiving plate. Deformation and wear become large, and even when a metal such as hardened steel is used for the receiving plate, there is a problem of large initial wear and uneven rotation due to lack of oil.

In the case of No. 3, ball bearings are generally more expensive than sintered bearings, and the problem is that they have a high noise level.

The present invention relates to a cup-shaped sintered alloy bearing characterized in that a thrust load is held at a shaft end.

The electric motor of the bearing mechanism according to the present invention generates less noise, less wear, and stabilizes and reduces rotational torque compared to a conventional electric motor that receives a thrust load at the end face of the bearing.

The first reason is that the runout of the bearing end face relative to the inner diameter is 0.02 m7 even when the outer diameter is about 10φ due to the limits of the fitting accuracy and press accuracy of the powder molding die! This means that it is difficult to keep it below L.

On the other hand, in the case of the cup-shaped bearing used in the present invention, the spherical surface or circular cylindrical surface of the cup bottom is molded by the core rod that molds the inner diameter part, so the runout of the center of the spherical surface or circular cylindrical surface with respect to the inner diameter is small. It is not affected by mold fitting accuracy or press accuracy, and can be finished with almost zero accuracy. Therefore, in the case of the present invention, the sliding contact surface is more uniform than the end surface contact of conventional cylindrical bearings. The second reason is that even at the same rotational speed, the sliding speed of the end face is farther than that of the bottom of the cup-shaped bearing in the case of the present invention. The third reason is that in the case of end face sliding, the lubricating oil that oozes out from the end face adheres to the rotating partner surface and is scattered by centrifugal force, but in the case of bottom face sliding of a cup-shaped bearing, There is no such concern and a good lubricating film can always be maintained. An advantage of the bearing mechanism of the tape recorder, video coater, and record player according to the present invention is that the ground from the rotating body can be taken directly from the cup-shaped bearing without using a brush. In the above application, the shaft end is rotated on a nylon plate as shown in Fig. 10 in consideration of noise and rotational unevenness, but electrical continuity between the shaft and the journal portion of the bearing is clear from the examples described below. As such, a grounding brush is necessary.

Another advantage of the bearing mechanism of the tape recorder/video coater/record player according to the present invention is that the initial wear of the thrust sliding surface is small.

In the conventional method where the shaft end is supported by a nylon plate, the shaft end and the nylon plate are in point contact at the beginning of sliding, so the sliding surface pressure is high and initial wear is large. The same applies when hardened steel is used instead of the nylon plate. In the case of the present invention, a spherical or circular recess is formed at the bottom of the cup-shaped bearing from the tip of the core rod or correction rod, depending on the shape of the shaft and end. can be avoided. When inserting a shaft into the cup-shaped sintered alloy bearing of the present invention, if the clearance between the shaft and the bearing is 0.02 mm or less, the air in the cup-shaped bearing will have nowhere to escape, and assembly will take time. In such a case, it is advisable to provide a groove like 24 in FIG. 1 or a pore for air vent near the bottom of the bearing in advance.

Furthermore, as another feature of the present invention, in the cup-shaped sintered alloy bearing of the present invention, the density of the bottom part is made higher than the density of the journal part, so that an oil film is easily formed in the thrust sliding part, and the thrust sliding resistance is reduced. There are things you can do to encourage yourself.

The oil-impregnating holes in general journal sliding sintered oil-impregnated bearings play the role of oil passage holes that supply oil, but they also act to release the pressure of the oil film on the sliding surface. An appropriate value must be selected depending on the In the case of the cup-shaped sintered alloy bearing of the present invention, oil gushing out from the journal sliding surface flows into the bottom and acts effectively on the thrust sliding surface, but in this case, if the density of the bottom is made higher than the density of the journal. The oil film on the thrust sliding surface is less likely to escape than the thrust sliding part, and stabilization of the thrust sliding is promoted. Moreover, the bearing of the present invention is made of a sintered alloy, and the bearing of the present invention is made of a sintered alloy.
As shown in the figure, the density of the bottom sliding surface can be easily increased by using core rods 10 during powder molding or by using core rods during sizing.

In some cases, there is an advantage that this density can be increased by using the tip of the inner diameter correction rod after the bearing mechanism is assembled. Examples are shown below.

The material of the sintered bearing used is JIS-Bl58l (19
75) and has a density of 6.8f1/C.
Although the material is bronze containing 10% TIL tin, it goes without saying that it is also applicable to sintered materials made of other materials such as iron-based and aluminum-based materials. In the electric motor for a ventilation fan, there are a method according to the present invention as shown in FIG. 1, a method of receiving the thrust load on the end face of a sintered bearing via a washer 12, and a method of using a ball bearing 13 as shown in FIGS. 8 and 9, respectively. I compared the three.

The motor was a 100 induction motor with a shaft diameter of 8φ, the lubricating oil used was #200 turbine oil, and the shaft was rotated vertically with the blades facing upward. Therefore, the thrust load applied to the bearing was adjusted to be approximately 3 kg, which is the sum of the rotor's own weight and the wind reaction force.

The shaft end was finished with a spherical surface of 8R, and the bottom of the cup-shaped sintered alloy bearing of the present invention was also molded with a recess of 8R. Rated 100
The noise level during operation was the worst for those using ball bearings, with a rasping noise that could be heard and the noise level was 65 horns. There was no big difference in the noise level between the one according to the present invention and the one with one washer sliding, ranging from 55 to 59 horns, but the noise level caused by the one sliding washer was audible. After operating in this state for 300 hours, it was stopped and the starting voltage was measured. The one using ball bearings and the one of the present invention are
Although it started at 81V, the one with one washers started at 95V for the first time. At this point, the noise level of the model according to the present invention and the model using ball bearings was 57 horns and 66 horns, respectively, which were the same as the initial state, but the noise level of the model with one sliding washer did not increase. It was a 62 horn. When the sliding washer was disassembled and investigated, it was discovered that the 0.2 mm thick nylon washer was extremely worn.

In the holding mechanism of a 10φ main shaft (SUS42O) of a direct drive type record player, the method of the present invention shown in Fig. 2 and the method (Fig. 10) using graphite-containing nylon sheet 14 and (SCM2l/HRC45) as thrust bearings. We compared the performance of

After 1000 hours of operation, the current consumption value and wow and flutter at the rated voltage were measured, and the stop time after the current was cut off was measured.

Furthermore, as shown in Figure 11, 0.1
A constant DC voltage was applied through a brush of Ω, and the electrical resistance between the shaft and bearing was measured. Furthermore, the amount of shaft sinking after 1000 hours of operation was measured.

The lubricating oil is Anderol #146, and the shaft end is 4R.
The bottom of the cup-shaped bearing was molded with a 4R spherical recess to a depth of 0.57nT1L. The results are summarized in Table 1.

It is clear from the current consumption and stop time that the wear torque of the present invention is smaller than that of the conventional method, and it can be seen that the rotational unevenness is smaller than the value of rewaw and flutter. According to the present invention, the electrical resistance between the shaft and the bearing is small and stable, which means that the rotating body can be grounded directly from the bearing without using a brush. Furthermore, it can be seen that in the case of the present invention, the wear at the initial stage of use is smaller than that of the conventional method. Furthermore, in this embodiment, the density of the bottom part is 0.0% lower than that of the journal part.
When using a bearing with a weight of 7.0 g, which is increased by 29 layers, the current consumption was 148 mA, and the stop time was 50.2 seconds. This confirms the effect of the present invention that the lubrication conditions are improved by increasing the bottom density.

[Brief explanation of drawings]

Figures 1, 2, 3, and 4 are all sectional views explaining the bearing mechanism using the bearing of the present invention, Figure 5 is a perspective view of the bearing of the present invention used in Figures 3 and 4, and Figure 6 is a conventional bearing. FIG. 7 is a sectional view showing a powder molding method for manufacturing a bearing of the present invention, FIG.
FIG. 10B1 FIGS. 12 and 13 are both cross-sectional views illustrating a conventional bearing mechanism, and FIG. 11 is an explanatory diagram showing a method for measuring bearing resistance. In each figure, 1 is the bearing of the present invention, 2 is the rotating shaft, and 3 is the bearing of the present invention.
indicates a conventional bearing.

Claims (1)

[Claims] 1. A cylindrical journal sliding part made of a sintered alloy, and a bottom sliding surface whose bottom is integrally provided at one end of the sliding part and has a shape that approximately matches the end face shape of the shaft. A thrust sliding portion is formed, and the density of the thrust sliding portion is greater than the density of the journal sliding portion. bearing.