JPS62100633A - Detecting escape of pre-load of bearing - Google Patents

Abstract

PURPOSE:To enable the escape of a pre-load to be easily and accurately detected by applying a load in an axial direction to the rotating shaft of a bearing and measuring the displacement of the rotating shaft in the axial direction for the applied load. CONSTITUTION:By lifting a bearing A a little from an index table 25, a rotating body abuts against the inner cylinder 23 of a guide member 21 and fixed by an energizing spring 24. Thus, the lower end surface of the rotating shaft 27 of the bearing A is brought into contact with the contactor 9 of a linear gage 8 and the upper end surface of the rotating shaft 27 is opposed to a load pin 19. When the linear gage 8 is set to zero and a support rod 17 is lowered by a load cylinder 18, a weight 14 descends while being guided by guided pins 13 and 13. The load pin 19, penetrated through a guide member 21, abuts against the upper end surface of the rotating shaft 27 of the bearing A and applies a load corresponding to the weight of the weight 14 to the rotating shaft 27. In such conditions, by reading the value indicated by the linear gage 8, the quantity of displacement of the rotating shaft 27 in an axial direction for the applied load can be measured.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a method for detecting preload loss in a bearing that rotatably supports a precision rotating body, such as a VTR cylinder, after the bearing is assembled.

(Technical backing of the invention and its problems) For example, in a VTR cylinder, a video head is provided on the outer periphery of a cylinder body made of a cylindrical body, and a video head is provided on the outer periphery of the cylinder body. It is designed to magnetically record and play back information. Therefore, even if the cylinder body is slightly shaken, the video head will no longer run at a predetermined position on the tape running surface, making magnetic recording and playback impossible, and causing image and audio disturbances.

Therefore, high precision is required for assembling the VTR cylinder, and after Il'l, C is also required to assemble each VTR cylinder.
The cylinder was measured to determine whether it was good or bad. That is, in addition to measurements such as measuring one rotational herb of the VTR cylinder and measuring the runout of the VTR cylinder, the nine sake cups are determined by actually playing back the VTR that recorded the specified signal in the 8 Hiiragi assembled product.

However, by measuring the rotational torque, it is not possible to determine whether the bearing that supports the VTR so that it can rotate freely is defective, or whether there is an abnormal rotation due to loss of preload in the bearing. There is an inconvenience that the measurement cannot determine whether the VTR cylinder itself is improperly bent with respect to its rotating shaft or whether the preload release of the bearing is defective.

For this reason, in order to recycle a defective product as a good product, a large amount of time is wasted by disassembling the product, inspecting the individual parts again, and reassembling the product for confirmation.

[Purpose of the invention]

This invention was made in view of the above-mentioned circumstances, and its purpose is to easily eliminate preload loss that affects the rotational torque and rotational runout of a bearing in which a rotating shaft is rotatably supported in a bearing body. The object of the present invention is to provide a method for detecting preload release of a bearing that can be detected accurately.

[Summary of the invention]

In order to achieve the above-mentioned object quickly, this invention applies an axial load to a rotating shaft while a bearing body is fixedly supported. The purpose of this method is to measure displacement in the direction and detect loss of preload in the bearing from the amount of displacement.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described based on the drawings.

First, the preload release detection device will be explained based on FIG. 1 and FIG. . An upper table 3 and a lower table 4 are provided on the idle rail 2 so as to be movable in the vertical direction. A letter-shaped immovable body 5 is integrally provided on the lower table 4, and this immovable body 5 is driven up and down by a lower cylinder 6 provided on the base 1. Further, a cylindrical bearing stand 7 is provided on the upper part of the immovable body 5, and is configured to place a bearing A, which will be described later. Roughly speaking, in this bearing, a linear gauge 8 as a displacement measuring means is provided concentrically inside the stand 7, and this contactor 9 faces the lower part of the bearing A.

On the other hand, the upper table 3 is integrally provided with an upper moving body 10 formed in a mouth shape. Furthermore, an upper cylinder 12 is provided on the base 1 located above the upper movable body 10 via a bracket 17, and the upper movable body 10 is driven up and down by this upper cylinder 12. Furthermore, a plurality of guide pins 13.13 are installed in the vertical direction between the upper plate 10a and the lower plate 10b that constitute the upper moving body 10, and these guide pins 13.1
Ways 1 to 14 as load applying means are supported by 3 so as to be vertically movable. The ways 1 to 14 have a disk shape, and a through hole 15 is formed in a part thereof in the vertical direction. A support rod 16 is installed in this through hole 15.
penetrates from above, and a retaining ring 17 is attached to the lower end. This support rod 16 passes through the upper plate 10a of the upper movable body 10 and is connected to a load cylinder 18 provided above. That is, the weight 14 is normally pulled upward by the load cylinder 18, but when the support rod 16 is lowered by the load cylinder 18, the weight 14 is lowered by its own weight.

Also, a load bin 1 is placed in the center of the bottom surface of this way 1.
9 protrudes downward, and this load bin 19 is attached to the holder 2.
The guide member 21 is inserted into the guide member 21 which is supported by the guide member 21. The guide member 21 includes an outer cylinder 22, an inner cylinder 23 inserted into the outer cylinder 22 so as to be vertically movable, and a spring 24 that biases the inner cylinder 23 downward. The load bin 19 is configured to pass through the inner cylinder 23 and face the bearing A, and the load bin 19 faces the contact 9 of the linear gauge 8 concentrically.

On the other hand, reference numeral 25 indicates a part of the index table, and workpiece support holes 26 are provided at equal intervals on the outer peripheral edge of the index table 25. Each of the bearings is supported in each of the workpiece support holes 26. As shown in FIG. 3, this bearing A is composed of a rotating shaft 27 and a bearing body 28 that rotatably supports the rotating shaft 27, and the axial movement of the rotating shaft 27 is restricted by preload. There is. In addition, the bearing body 28 of the bearing A is supported on the edge of the workpiece support hole 26, and the intermittent rotation of the index table 25 causes the bearing A to move between the table 7 and the load bin 19. is being supplied to.

Next, a method for detecting preload release of the bearing A using the preload release detection device configured as described above will be explained. When the index table 25 is rotated intermittently with the lower cylinder 6 lowering the immovable body 5 and the upper cylinder 8 raising the upper movable body 6, the bearing A supported in the workpiece support hole 26 is rotated. It is positioned and stopped between the stand 7 and the guide member 21. In this state, upper cylinder 8
When the upper moving body 10 is lowered to a predetermined position by the lower cylinder 6 and the immovable body 5 is raised by the lower cylinder 6,
The bearing base 7 passes through the workpiece support hole 26 and supports the bearing body 28 of the bearing A from below. That is, by slightly lifting the bearing A from the index table 25, the rotating body 30 comes into contact with the inner cylinder 23 of the guide member 21, and the biasing spring 2
4, the rotating body 30 is held and fixed. When the bearing A is set in this way, the lower end surface of the rotating shaft 27 of the bearing A comes into contact with the contact 9 of the linear gauge 8, and the rotating shaft 27
The upper end surface of is opposed to one load bin.

Here, when the linear gauge 8 is set to zero and the support rod 17 is lowered by the load cylinder 18, the weight 14 is lowered while being guided by the guide rods 13 and 13. Then, the load bin 19 is connected to the guide member 21.
The weight 14 passes through the shaft and comes into contact with the upper end surface of the rotating shaft 27 of the bearing A, and applies a load equivalent to the weight 14 of heavy machinery to the rotating shaft 27. By reading the indicated value of the linear gauge 8 with a load applied to the rotating shaft 27 in this manner, it is possible to measure the amount of displacement of the rotating shaft 27 in the axial direction with respect to the load.

That is, by comparing the amount of displacement with a preset value, it is possible to determine whether the bearing A is good or bad. For example, when the specified preload is 2 ± 250 g, the displacement at 2 kg is 7
If it is ±1μ, if it is 8μ or more, it may be judged that the preload is out of specification and the preload is missing (even if it is less than 6μ, the preload will become large for some reason, and it is expected that the rotational torque will be out of specification. ), it can be determined that the preload is defective if the amount of displacement is outside 7±1μ. Figure 4 shows the relationship between the load on the rotating shaft 27 of bearing A and the amount of displacement.
The figure shows the displacement in response to the load when the lock is 200g, and the hatched line indicates the amount of displacement in response to the load when the lock is 200g. As is clear from this graph, if the preload is lost for some reason, the amount of displacement increases, and the loss of preload can be detected.

In this way, the loss of preload in the bearing A was detected by raising the weight 14 using the load cylinder 18, separating the load bottle 19 from the rotating shaft 27, and pressing the upper cylinder 1
2, the moving body 10 is raised. Further, the immovable body 5 is lowered by the lower cylinder 6, and the receiver platform 7 is pulled out from the workpiece support hole 26. Then, the index table 25 is rotated intermittently to set the next bearing A to the preload detection position.

In the above embodiment, a method for detecting preload on a bearing of a VTR cylinder has been described, but the present invention can be applied to detecting preload on any bearing used in a precision instrument. Further, although a weight is used as the Y pressure applying means, the present invention is not limited to this, and the load may be applied using a spring, a cylinder, or the like. Furthermore, the means for measuring the amount of displacement is not limited to a linear gauge, but may also be an electric micrometer or an optical sensor. Further, the lower initial drive device of the vertically movable body is not limited to a cylinder, but may have a structure in which a screw rod is rotated by a motor to be driven.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to apply an axial load to the rotating shaft of the bearing and detect the preload release (J) based on the axial displacement surface of the rotating shaft at this time. , it is possible to independently inspect preload loss that affects one rotational herk of the rotating body and rotational vibration, and it is also possible to regenerate defective products into good ones in the cylinder, significantly reducing the time required for the regeneration process as well as the inspection process. can do.

[Brief explanation of drawings]

FIG. 1 is a side view showing an embodiment of a preload detection device used in the preload detection method of the present invention, FIG. 2 is a perspective view, and FIG. 3 is a vertical front view showing a bearing of a general VTR cylinder. FIG. 4 is a graph showing the relationship between axial load and displacement amount. 8... Linear gauge (displacement measurement means), 14...
Weight (preload applying means), 27... rotating shaft, 28...
Bearing body. Applicant's agent Patent attorney Takehiko Suzue Figure 1〈 α) Thief 11111m ”z

Claims (1)

[Claims] When detecting preload loss in a bearing consisting of a rotating shaft and a bearing body that rotatably supports the rotating shaft and restrains movement of the rotating shaft in the axial direction by preload, the bearing body is fixedly supported. a load applying means for applying an axial load to the rotating shaft in a state in which a load is applied to the rotating shaft by the means, and measuring the axial displacement of the rotating shaft in response to the load with the load being applied to the rotating shaft by this means, and determining the preload of the bearing from the amount of displacement. A method for detecting preload loss in a bearing, comprising a displacement measuring means for detecting loss of preload.