JPH10239189A - Method and apparatus for applying pre-load - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for applying a pre-load that can measure the pre-load being applied to the ball bearing of a rotor support immediately after application of the pre-load or during application of the pre- load. SOLUTION: A weight 8 for operating a weight driver 13 lowers to apply a load in the axial direction to the inner ring of first and second ball bearings 1, 2 mounted on the flange 5 of a rotary head drum 9. Lowering amount of a shaft 3 displaced by applying the load is measured by means of a noncontact displacement sensor 10 and a pre-load being set for the first and second ball bearings 1, 2 can be grasped based on the lowering amount of the shaft 3. The pre-load is held by securing a pre-load nut 6 to the shaft 3 by means of a driver unit 11 under that state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a preload applying method and a preload applying device, and more particularly to a preload applying method and a preload applying device capable of confirming a preload amount when a preload is applied to a ball bearing.

[0002]

2. Description of the Related Art In a manufacturing process of a rotating body supporting device having a ball bearing such as a rotating head drum device used in a VTR, a clearance of the ball bearing is eliminated.
Usually, a preload is applied (load is applied in the axial direction) to increase the rigidity of the ball bearing. The preload amount is
It is important to apply an appropriate amount of preload to the ball bearing because it affects the wear, temperature, life, etc. of the ball bearing. Conventionally, to check the amount of preload applied to ball bearings, assemble the rotator support device until it can be rotated by a motor, actually rotate the rotator support device, and measure the current consumption of the motor The amount of preload applied to the ball bearing could not be measured and confirmed immediately after the preload was applied to the ball bearing or during the application of the preload.

Therefore, since the preload amount is confirmed only after the rotating body supporting device is rotated and the power consumption of the motor is measured or the like, the man-hour required to check the preload amount is large, and it is difficult to find out the preload failure in advance. could not. In addition, if the preload is poor, it requires a man-hour to repeat the adjustment of the preload amount,
This was one of the factors that hindered the productivity of the rotating body support device.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to measure and confirm the amount of preload applied to a ball bearing of a rotating body support device immediately after or during application of preload. It is an object of the present invention to provide a preload applying method and a preload applying device which can perform the preload applying.

[0005]

In order to solve the above-mentioned problems, a preload applying method according to the present invention is directed to a preload applying method for applying a preload to a ball bearing of a rotating body supporting device, the method comprising: A step of applying a load to one of the inner and outer rings, a step of measuring the axial displacement of one of the inner ring and the outer ring displaced by applying a load to either the inner ring or the outer ring, and applying the load. Fixing one of the inner ring and the outer ring in the state as it is, and measuring the amount of preload applied to the ball bearing from the measured amount of displacement.

Further, the preload applying device of the present invention is a preload applying device for applying a preload to a ball bearing of a rotating body supporting device, wherein the mounting table on which the rotating body supporting device is mounted and the inner ring or the outer ring of the ball bearing are provided. A weight that applies a load to one of them in the axial direction, a weight drive device that raises and lowers the weight, and an axial displacement amount of one of the inner ring and the outer ring that is displaced by applying a load to either the inner ring or the outer ring. It is characterized by having a displacement measuring means for measuring, and fixing means for fixing either the inner ring or the outer ring while a load is applied to either the inner ring or the outer ring.

The above-described step of measuring the displacement and the displacement measuring means correspond to the displacement of either the inner ring or the outer ring when the displacement of either the inner ring or the outer ring cannot be directly measured. It may measure the amount of displacement of another part, for example, a shaft or a housing of the rotating body supporting device.

According to the present invention, an axial displacement amount of one of the inner ring and the outer ring (or another equivalent thereof) displaced by applying a load from the axial direction to either the inner ring or the outer ring of the ball bearing. The amount of preload applied to the ball bearing can be checked immediately after the preload is applied or during the preload application to measure the preload set for the ball bearing from this displacement. it can.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

First, the principle of measuring the preload amount in the preload applying method of the present invention will be described. As a method of applying a preload to the ball bearing, there are a constant pressure preload and a fixed position preload.
For fixed position preload, furthermore, the outer ring of the ball bearing is fixed and a load is applied to the inner ring to displace the inner ring, and the inner ring preload is applied to apply the preload. Therefore, there are two methods of applying a preload and an outer ring preload. The present invention relates to fixed position preload, and includes both cases of inner ring preload and outer ring preload.

An axial load (hereinafter, referred to as a ball bearing)
Axial load) and apply a preload,
A step (hereinafter, referred to as axial displacement) occurs between the inner ring and the outer ring. FIG. 1 is a graph showing a relationship between an axial load and an axial displacement. The axial displacement is
Since the axial load increases with the tendency as shown in FIG. 1, by knowing the relationship between the axial displacement and the axial load in advance, the preload amount applied to the ball bearing can be known from the axial displacement amount. It should be noted that the same tendency as in FIG. 1 is obtained when two ball bearings are used in combination at the top and bottom, as in the rotary head drum device of the embodiment described later.

FIG. 2 is a cross-sectional view schematically showing displacement when an inner ring preload is applied to a ball bearing of a rotary head drum device used in, for example, a VTR. FIG. 2A is a state before the preload, and FIG. (B) is the state after the preload. 3A and 3B are cross-sectional views schematically showing displacements when an outer ring preload is applied to a ball bearing of the rotary head drum device. FIG. 3A is a state before the preload, and FIG. This is the state after the preload. The rotary head drum device includes first and second ball bearings 1 and 2, a shaft 3, a housing 4,
It has a flange 5 and a preload nut 6. The inner rings 1a and 2a of the first and second ball bearings 1 and 2
The outer races 1 b and 2 b of the first and second ball bearings 1 and 2 are mounted on the housing 4. In FIGS. 2 and 3, only the peripheral portion of the ball bearing is shown for ease of explanation, and other components necessary for the rotary head drum device are not shown. Reference numeral 7 denotes a mounting table of the preload application device on which the rotary head drum device is mounted when the preload is applied.

In the case of the inner ring preload, as shown in FIG. 2A, the inner ring 1a of the first ball bearing 1 is
Inner ring 2 of the second ball bearing 2
a is supported by the preload nut 6, and FIG.
The weight 8 is mounted on the flange 5 as shown in FIG.
A load is applied to 2a from the axial direction. If it is impossible to measure the displacement of the inner ring 1a in the axial direction or the displacement of the inner ring 1a directly due to the structure, for example, the displacement A of the shaft 3 in the axial direction
And the like, it is possible to grasp the applied preload amount. In the case of the outer ring preload, as shown in FIG. 3A, the outer ring 1b of the first ball bearing 1 is supported by the housing 4 and the second ball bearing 2
The outer ring 2b is supported by a preload nut 6, and as shown in FIG. 3B, a weight 8 is placed on the housing 4 to apply a load to the outer rings 1b and 2b in the axial direction. The amount of displacement of the outer ring 1b in the axial direction, or the outer ring 1b
If it is not possible to measure the displacement of
By measuring the amount of displacement B in the axial direction, etc., the applied preload amount can be ascertained.

Next, a preload applying apparatus according to the present invention using the above-described principle will be described with reference to FIG. Here, a case where the inner ring preload is applied to the ball bearing of the rotary head drum device as described with reference to FIG. 2 will be exemplified.
FIG. 4A is a schematic side view showing an embodiment of the preload application device according to the present invention, and FIG. 4B is a cross-sectional view showing a state where the rotary head drum device 9 is mounted on the mounting table 7 of the preload application device. FIG. Note that all of the reference numerals described in FIG. 2 are not given in FIG. 4, but the description includes the reference numerals in FIG. 2.

The preload applying device is a rotary head drum device 9
, A non-contact displacement sensor 10 mounted inside the mounting table 7, a driver unit 11 for fixing the preload nut 6, and an axial load applied to the inner ring of the ball bearing. It comprises a weight 8, a weight support plate 12 for supporting the weight 8, a weight driving device 13 such as an air cylinder for raising and lowering the weight 8, and an operation unit 14 for performing various operations of the preload application device. As the non-contact displacement sensor 10, an eddy current displacement sensor, a capacitance displacement sensor, or the like can be used.

Next, the operation of the preload applying device will be described. First, the rotary head drum device 9 with the housing 4, the first and second ball bearings 1 and 2, the rotary transformer (not shown), and the flange 5 mounted on the shaft 3 is mounted on the mounting table 7. When the start switch of the unit 14 is pressed, the weight 8 is lowered integrally with the weight support plate 12 by the operation of the weight driving device 13, and is mounted on the flange 5 of the rotary head drum device 9, and the inner rings 1 a, 2 a
Load is applied from the axial direction.

FIG. 5 shows the weight 8 and the weight support plate 12.
3A is a side view showing the positional relationship, wherein FIG. 3A shows a state in which preload is not applied, and FIG. 3B shows a state in which preload is applied. The weight 8 has a tapered positioning pin 8a formed thereon, and the weight support plate 12 has a positioning pin 8a.
A hole 12a is formed at a position facing "a". FIG.
As shown in (a), when no preload is applied, the weight 8 is supported by the weight support plate 12, and the positioning pin 8a is loosely fitted into the hole 12a to perform positioning. When the preload is applied, when the weight 8 rests on the flange 5, only the weight support plate 12 continues to descend and stops in a state as shown in FIG. 5B. That is,
During application of the preload, the weight 8 is separated from the weight support plate 12 so as not to interfere anywhere so that the load is completely applied to the flange 5.

After the weight 8 has been lowered, the driver unit 11 advances toward the rotary head drum device 9. When a load is applied to the flange 5, the inner ring 1a of the first ball bearing 1 descends, and accordingly, the shaft 3 also descends. The amount of downward movement of the shaft 3 is measured by the non-contact displacement sensor 10. The operator operates the driver unit 11 to fix the preload nut 6 to the shaft 3 by screwing, while confirming the descending amount. As a result, the inner rings 1a, 2a of the first and second ball bearings 1, 2 are fixed to the shaft 3, and the preload is maintained. After the preload nut 6 is fixed, the descending amount of the shaft 3 is confirmed again, and it is confirmed that the preload is completely applied to the first and second ball bearings 1 and 2. Then, the return switch of the operation unit 14 is pressed down, and the driver unit 11 is moved backward.
Is raised to end the preload application operation.

According to the preload application method as described above, the preload amount can be grasped by measuring the descending amount of the shaft 3, so that the preload nut 6 can be fixed while confirming the preload amount. An appropriate amount of preload can be applied to the second ball bearings 1 and 2. Also, since the preload amount can be confirmed immediately after the preload nut is fixed, it can be confirmed that the set preload amount is reliably applied. Therefore, preload failure at the time of preload application can be significantly reduced. Also,
When measuring the descending amount of the shaft 3, the non-contact type displacement sensor 10
Is used, it is possible to absorb the influence of the surface roughness, inclination, and the like of the measurement location, and reduce the measurement error.

Although the embodiment has been described in detail above, the present invention is not limited to this, and the case where the outer ring preload is applied to the ball bearing based on the principle described with reference to FIG. Can also be applied. Also,
The present invention is not limited to the rotary head drum device described above, and can be widely applied to a case where a preload is applied to a ball bearing of another rotary member supporting device.

[0021]

According to the present invention, since the preload can be applied while confirming the preload applied to the ball bearing, an appropriate preload can be applied to the ball bearing in a short time. At the same time, a poor preload of the ball bearing can be prevented.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between an axial load applied to a ball bearing and an axial displacement.

FIG. 2 is a cross-sectional view schematically showing displacement when an inner ring preload is applied to a ball bearing.

FIG. 3 is a cross-sectional view schematically showing displacement when an outer ring preload is applied to a ball bearing.

FIG. 4 is a diagram showing an embodiment of the present invention;
(A) is a schematic side view of a preload application device, (b) is a cross-sectional view showing a state where a rotary head drum device is mounted on a mounting table of the preload application device.

FIG. 5 is a side view showing the positional relationship between the weight and the weight support plate of the preload applying device of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... 1st ball bearing, 2 ... 2nd ball bearing, 1a, 2a ... inner ring, 1b, 2b ... outer ring, 3 ... shaft,
4 ... housing, 5 ... flange, 6 ... preload nut, 7 ...
Mounting table, 8 weight, 8a positioning pin, 9 rotary head drum device, 10 non-contact displacement sensor, 11 driver unit, 12 weight support plate, 12a
... holes, 13 ... weight drive device, 14 ... operation unit

Claims (4)

[Claims] 1. A preload applying method for applying a preload to a ball bearing of a rotating body supporting device, wherein a step of applying a load to one of an inner ring and an outer ring of the ball bearing from an axial direction; A step of measuring an axial displacement of one of the inner ring and the outer ring displaced by applying a load to one side; and a step of fixing one of the inner ring and the outer ring while the load is applied. And measuring a preload amount set for the ball bearing from the displacement amount. 2. A preload applying device for applying a preload to a ball bearing of a rotator supporting device, comprising: a mounting table on which the rotator supporting device is mounted; and one of an inner ring and an outer ring of the ball bearing from an axial direction. A weight that applies a load, a weight drive device that raises and lowers the weight, and a displacement that measures an axial displacement of one of the inner ring and the outer ring that is displaced by applying a load to one of the inner ring and the outer ring. A preload applying device, comprising: a quantity measuring means; and a fixing means for fixing one of the inner ring and the outer ring while a load is applied. 3. The preload applying apparatus according to claim 2, wherein said displacement amount measuring means is a non-contact type displacement sensor attached to said mounting table. 4. The apparatus according to claim 1, further comprising a weight support plate that separates from the weight when the weight applies a load and that supports the weight when the weight does not apply a load. 3. The preload applying device according to 2.