JPH076857B2 - Bearing sorting device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an apparatus for measuring bearing rotational torque and selecting bearings.

[Prior Art] Bearings, especially rolling bearings, have variations in rotational torque due to variations in precision of parts during manufacturing. Therefore, in order to obtain, from the manufactured bearings, the rotational torque within the allowable range regarding the preset reference rotational torque, the rotational torque of each bearing is measured (sorting work).

In the measurement of such bearing rotation torque, the outer ring of the bearing to be measured is fixed so as not to rotate, and the inner ring under a thrust load applied via a spindle is rotated by a motor. At the time of this measurement, the motor is driven at a constant speed with respect to the reference torque such as the rotational torque predicted before the measurement of each measured bearing, the rotational torque of the bearing supporting the spindle, and the rotational torque of the motor. The required reference current value is calculated in advance. Since the measured bearing rotates at a constant speed, a drive current corresponding to the rotational torque of the measured bearing is passed through the motor. here,
By comparing this drive current value and the reference current value,
The rotational torque of the bearing to be measured and the deviation amount from the reference rotational torque are measured.

Further, as another technique for measuring the rotational torque of a bearing, a torsion bar is interposed between the spindle that contacts the inner ring of the bearing to be measured and the motor, and the distortion amount of the torsion bar due to the driving of the motor is measured. There are also things.

[Problems to be Solved by the Invention] In the above-described conventional example, the magnitude and variation of the rotational torque of the rolling bearing that supports the spindle are large when the bearing to be measured is relatively large, for example, for a ship. It is extremely small compared to those of the measured bearing. Therefore, the influence of the rotational torque on the spindle and its variation can be ignored, and the rotational torque of the bearing can be measured with relatively good accuracy. On the other hand, in a small bearing used for a capstan of a video deck, a rotary head, or the like, the rotation torque is also extremely small. When trying to measure the rotating torque of such a small bearing by the measuring device of the conventional example, the magnitude and the variation of the rotating torque of the rolling bearing supporting the spindle become a significant value compared with those of the measured bearing. In addition, there is a problem that accurate measurement becomes difficult. In particular, two rolling bearings are frequently used for supporting the spindle, and the variation in the torque related to the spindle is often larger than that of the measured bearing, which is a serious problem.

Further, the bearing may be provided with a seal material at an axial end portion between the inner ring and the outer ring, and further, grease may be filled inside. In manufacturing these types of bearings,
Whether or not the bearing should be provided with a sealant is inspected visually by an operator, or by shining light on the axial end of the bearing to see if the sealant is present. It was done by determining the presence or absence of. Such a conventional method has problems that workability is poor and the process is complicated. Also, in the case of bearings that should be filled with grease, and in the case of bearings that have a sealant, it is not possible to inspect for grease after completion, so it is the type of bearing that should be filled with grease. However, there is a risk of shipping defective products that are not filled with grease.

The object of the present invention is to solve the above technical problem, to measure the rotational torque of the bearing and to select the bearing, the extremely small rotational torque can be detected with high accuracy, and the workability of the step of selecting the bearing can be improved. An object of the present invention is to provide a bearing selection device that can be significantly improved.

[Means for Solving the Problem] The present invention provides a fixing means for fixing an outer ring of a rolling bearing to be sorted, a spindle in which a free end portion abuts on the inner ring in the axial direction, and a static pressure air bearing for supporting the spindle. , A means for rotationally driving the spindle, a measuring means for measuring the rotational torque of the spindle, and a means for responding to the output of the measuring means and comparing the measured rotational torque with a predetermined reference torque for selection. It is a characteristic bearing selection device.

[Operation] In the bearing selection device of the present invention, the hydrostatic air bearing that supports the spindle has a rotational torque that is extremely small with respect to the rotational torque of the measured rolling bearing, for example, one digit to two digits. Moreover, the variation in the rotational torque of the hydrostatic air bearing is extremely small, and the rotational torque of the hydrostatic air bearing supporting the spindle hardly affects measurement (selection). Therefore, even if the selected bearing is relatively small and its rotational torque is very small, it can be detected with high accuracy. In addition, the rotational torque differs depending on the size of the bearing, whether or not a seal material is provided at both ends in the axial direction of the bearing, and whether or not grease is filled inside the bearing.Measure the reference rotational torque corresponding to each case. In addition, the bearing selection work can be performed with high workability simply by comparing the actual measurement value with this.

[Embodiment] FIG. 1 is a front view including a partial cross-section showing a configuration of a bearing sorting apparatus 1 according to an embodiment of the present invention. Bearing selection device 1
Is a static pressure air bearing (hereinafter referred to as a static pressure air bearing) that has a holding device 3 that is a fixing unit that holds the rolling bearing 2 to be selected and a motor that rotationally drives a spindle 4 that passes through the holding device 3 and that supports the spindle 4. A bearing device) 5 and a rotary encoder 6 for detecting the rotation speed of the spindle 4. The holding device 3, the bearing device 5, and the rotary encoder 6 are integrally configured and fixed to the moving member 7.
In the rated rotation state, the bearing device 5 has a rotation torque of about 0.3 to 0.8 g · mm due to friction associated with the rotation of the bearing device 5, and there is almost no variation. On the other hand, the small bearing 2 used in the capstan of a VCR is a grease-filled type bearing with a rotational torque of 9.0.
Approximately 14 g · mm, which is a grease-free type and has a rotational torque of approximately 3-5 g · mm. Therefore, the detection of the rotational torque of the bearing 2 is configured to be almost completely unaffected by the rotational torque of the bearing device 5. The moving member 7 is provided so as to be movable in the vertical direction of FIG. 1 along the rail 8, and the upper end portion thereof is fixed to the rod 10 of the air cylinder 9. The air cylinder 9 and the rail 8 are integrally fixed to the base 11.

The holding device 3 is a step portion that fits with the outer ring 12 of the rolling bearing 2.
13 is a tapered fixing member 14 formed on the inner peripheral surface of the free end.
And a cylindrical housing 15 to which the fixing member 14 is detachably and coaxially connected. In the housing 15,
A rotating member 19 fixed to the spindle 4 is rotatably provided. The rotating member 19 is formed with a cylindrical insertion hole 16 into which the spindle 4 is inserted, and a cylindrical accommodation recess 18 in which the coil spring 17 is accommodated between the rotation member 19 and the spindle 4.

At the lower end of the spindle 4, a salvis 20 having a flat surface facing downward is screwed. Inside the fixing member 14,
A rotary member 21 having a substantially U-shaped cross section parallel to the axis is housed coaxially with the spindle 4. The rotating member 21 has a fitting hole 23 formed in the bottom portion, into which the base end portion of the rotating shaft 22 is fitted, and a rotating cylinder 24, which is rotatable with the spindle 4 and is fixedly housed in the inner upper portion. There is. The tip of the rotary shaft 22 is configured to be fitted into the inner ring 28 of the rolling bearing 2. A rolling element 27 is interposed between the outer ring 12 and the inner ring 28.
A sealant (not shown) may be attached to both sides of the bearing 2 in the axial direction. The flange 25 formed on the rotary cylinder 24 covers the upper end of the rotary member 21 and faces the lower end of the rotary member 19 with a gap 26 therebetween. Further, a spline (not shown) is formed between the rotary member 19 and the flange of the rotary cylinder 24, and the rotary member 19 and the rotary cylinder 24 are configured to rotate together.

FIG. 2 is a cross-sectional view showing a configuration related to the bearing device 5. The bearing device 5 includes a substantially cylindrical housing 29, and a rotary shaft 30 is housed inside. The end of the rotary shaft 30 is energized via a power line 76. The rotating shaft 30 is a motor
It is fixed coaxially to the rotor 32 of 31, passes through the motor 31, and is inserted into the rotary encoder 6. The rotary encoder 6 outputs a pulse signal whose frequency changes according to the rotation speed of the rotary shaft 30, has a well-known configuration, and a detailed description thereof will be omitted. The pulse signal is taken out via the lead wire 33.

The rotary shaft 30 has a flange 35 formed inside the housing 29. Further, the housing 29 is formed with a cylindrical storage portion 37 for storing the shaft-shaped portion 36 of the rotary shaft 30 and a recess 38 having a diameter larger than that of the storage portion 37 and storing the flange 35, which communicate with each other. Has been done.

A bearing sleeve 39 is arranged between the bearing metal 29 and the rotating shaft 30 near the lower end of the storage portion 37, and is fixed to the housing 29. A bearing sleeve 41 having a flange 40 is mounted on the flange 35 side of the bearing sleeve 39. The bearing sleeve 41 is interposed between the storage portion 37 and the shaft portion 36. The flange 40 supports the flange 35 of the rotary shaft 30 from the lower side in the thrust direction. Further, an annular thrust plate 42 is arranged above the recess 38 that houses the flange 35 of the rotary shaft 30.

A pipe joint 43 for introducing pressurized air to the inside of the housing 29 is screwed into the housing 29, and an air flow path 44 communicating with the pipe joint inside the housing 29 surrounds the storage hole 37 and the recess 38. It is formed along the route. Recessed grooves 45 and 46 communicating with the flow path 44 are formed over the entire inner peripheral surface of the housing portion 37 of the housing 29. On the other hand, the bearing sleeves 39 and 41 are formed with nozzles 49 and 50 that individually face the concave grooves 45 and 46.

An exhaust hole 53 communicating with the housing portion 37 is formed in the housing 29 at a position facing the pipe joint 43 in the radial direction.
An exhaust connector 54 is screwed onto the. The bearing sleeve 41 is formed with a communication hole 55 that connects the interior of the storage portion 37 and the recess 38. The flange 40 of the bearing sleeve 41 and the thrust plate 42 are also in communication with the flow path 44, and the flange 35 of the rotating shaft 30.
Nozzles 56 and 57 facing the front are formed.

The housing 29 is composed of a main body 60 and a cover body 61, a spacer 58 is interposed between them, and the spacer 58 has a flow path.
A through hole 59 which is a part of 44 is formed. Spacer 58
Are hermetically sealed together with the main body 60 and the cover body 61.

FIG. 3 is a block diagram illustrating the electrical configuration of the bearing selection device 1. The bearing selection device 1 is shown in FIG. 1 based on a signal from a phase locked loop (hereinafter abbreviated as PLL) circuit 62 for controlling the rotation speed of the motor 31 to a predetermined rotation speed and a signal from the PLL circuit 62. And a torque detection circuit 63 for detecting the rotation torque of the rolling bearing 2 as the rotation torque of the motor 31. The PLL circuit 62 is the motor 3
The rotation speed of 1 is detected and the corresponding pulse signal P of frequency fm
The rotary encoder 6 that outputs m and the reference oscillating circuit 64 that generates the reference pulse signal Ps having the reference frequency f0 corresponding to the reference rotation speed set in the motor 31 are configured. Note that the reference oscillation circuit 64 may be implemented by, for example, a crystal oscillator. The outputs from these are compared in phase by the phase comparison circuit 65, a signal corresponding to the phase difference δ is output to the low-pass filter 66, and the phase difference δ
The level signal SL is output from the rotary encoder 66 as a DC voltage of a level corresponding to.

The output of the rotary encoder 6 is also input to the direction discriminating circuit 67 to discriminate the rotation direction of the motor 31. Direction discrimination circuit
The signal from 67 is input to the rotor position detection circuit 68, and the reference position in the circumferential direction of the rotary shaft 30 is detected. Based on the output of the rotor position detection circuit 68, the sine wave generation circuit 69
A sine wave is generated in synchronization with the timing when the rotary shaft 30 passes through the reference position along the circumferential direction detected by the rotor position detection circuit 68.

The generated sine wave is input to the level adjustment circuit 70.
The level adjusting circuit 70 adjusts the amplitude level of the sine wave generated by the sine wave generating circuit 69 in response to the DC level signal SL input from the low pass filter 66. When the sine wave from the level adjusting circuit 70 is input to the drive circuit 71, three-phase AC power of a level required to drive the motor 31 is generated and supplied to the motor 31 via the power line 76. The current detection circuit 72 provided in the power line 76 detects the current value of the power line 76 and outputs it to the drive circuit 71. As a result, the drive circuit 71 outputs a current within a predetermined level range to the power line 76.

An offset adjustment circuit 73 is provided in the torque detection circuit 63, and the output from the low pass filter 66 is input.
The offset adjusting circuit 73 is a circuit for removing the rotational torque component in the bearing device 5 and the holding device 3 in the unloaded state from the rotational torque of the motor 31 detected as the level signal SL from the low pass filter 66. This rotational torque component is calculated in advance. The outputs from the rotary encoder 6 and the reference oscillation circuit 64 are input to the lock state detection circuit 74, and the frequency fm of the pulse signal Pm and the reference pulse signal are input.
It is detected whether or not the reference frequency f0 of Ps is within the range of | fm−f0 | ≦ Δf (1) with respect to the predetermined allowable range Δf. That is, the PL of this embodiment
The L circuit 62 determines whether or not the motor 31 is properly controlled. If the rotation speed of the motor 31 is outside the control range of the PLL circuit 62, it becomes difficult to control the rotation speed of the motor 31 to a predetermined constant speed. In such a case, the rotation torque of the rolling bearing 2 is Proper measurement operation becomes impossible.

When the control of the rotation speed of the motor 31 is in the lock state described above, the output circuit 75 outputs the output signal Vtrq as a voltage level corresponding to the rotation torque to the rolling bearing 2 based on the signal from the offset adjustment circuit 73. Or display and output various data based on the rotation torque.

FIG. 4 is a time chart showing the phase relationship between the reference pulse signal Ps and the pulse signal Pm. From the reference oscillating circuit 64, the reference pulse signal Ps of the frequency f0 shown in FIG.
Is output, and the pulse signal Pm is output from the rotary encoder 6.
Is output. The rotary encoder 6 is illustrated in FIG. 4 (2) or FIG. 4 (3) with respect to the reference pulse signal Ps according to the degree of the rotation torque of the rolling bearing 2 mounted on the motor 31 via the holding device 3. Phase difference δ1
Alternatively, the pulse signal Pm having the drive frequency fm having the phase difference δ2 (generally indicated by the signal δ) is output. Then, the phase comparison circuit 65 detects the phase differences δ1 and δ2.

FIG. 5 and FIG. 6 are graphs showing the relationship between the phase difference δ, the rotational torque serving as the load of the motor 31, and the drive current I to the motor 31, respectively. When the offset rotation torque f1 of the motor 31 itself produces the phase difference δ1 with respect to the reference pulse signal Ps, the rotation torque f2 (f1 ≦ f2) when the rolling bearing 2 is mounted causes the torque difference shown in FIG. A phase difference δ2 (δ1 ≦ δ2) is generated. The PLL circuit 62 controls such that the phase differences δ1 and δ2 are set to 0. As shown in FIG. 6, the motor 31 is driven by the drive currents I1 and I2 at the levels corresponding to the levels of the phase differences δ1 and δ2. To drive.

FIG. 7 is a graph showing the relationship between the rotation speed n (rpm) of the motor 31 and the output voltage Vtrq from the output circuit 75. line
sp1 indicates the case where the rolling bearing 2 has neither sealing material nor grease, lines g1 and g2 both indicate the permissible range of the rotational torque of the rolling bearing 2 which has only grease, and lines gs1 and gs2 both indicate The allowable range of the rotation torque of the rotary bearing 2 provided with two seal materials and grease is shown.

Therefore, the rolling bearing 2 is mounted on the bearing sorting device 1 and the rotation speed is set to n1, n2, n3, n4 (for example, 500 rpm, 1000 rpm, 15 rpm).
The rotation torque at that time is measured as 00 rpm, 1900 rpm). At this time, when the rolling bearing 2 is of a type including a sealant and grease, for example, and the measured rotational torque is located below the line gs2 in FIG. 7, at least one of the grease and the sealant is missing. You can know what you are doing. Also, the measurement result is line gs
If it is located above 1, it may be inferred that the contained rolling element 27 is missing. The output circuit 75 is a rolling bearing 2 to be measured.
Comparing the preset specifications of, i.e., the predetermined reference torque with the measured rotation torque that is the measurement result,
The various abnormal states or the conforming states are displayed and output, whereby the rolling bearings can be selected.

In addition, when the selection position 1 of the bearing is idle, that is, the bearing 2
When the bearing sorting device 1 itself was operated without setting, the torque was about 5 g · mm, and there was almost no variation in the torque.

As described above, in the present embodiment, for example, the rotation torque of the rolling bearing 2 can be measured with high accuracy even if the rotation torque is relatively small, and the rolling bearing 2 can be measured based on the measured rotation torque. It is possible to select good products or defective products. This improves the workability of the rolling bearing 2 selection process.

[Advantages of the Invention] According to the invention as described above, the spindle is supported by the hydrostatic air bearing, and the rotating torque when the spindle is rotated is measured by the measuring means. With respect to the measured rotation torque of the spindle, the influence of the rotation torque of the bearing supporting the spindle in addition to the rotation torque of the selected rolling bearing can be suppressed as much as possible. Therefore, even if the selected rolling bearing is relatively small and its rotational torque is very small, it can be detected with high accuracy. In addition, the rotational torque will differ depending on the size of the rolling bearing, whether or not sealing materials are provided at both ends of the rolling bearing in the axial direction, and whether or not grease is filled inside. By simply measuring the rotational torque and comparing the actual measured value with this, the rolling bearing selection work can be performed with high workability.

In the conventional bearing sorting device, the inner ring is fixed and the outer ring is rotated. In the bearing sorting device, the outer ring is fixed and the inner ring is rotated.
That is, by adopting a configuration in which the rotational driving force is applied to the inner ring, it is possible to downsize the means for relatively rotating the inner ring and the outer ring. Therefore, the bearing sorting device has the advantage that the entire device is compact.

In particular, in the present invention, since the spindle abutting on the inner ring is supported by the hydrostatic air bearing, the rotational torque of the hydrostatic air bearing can be, for example, one digit to two digits with respect to the rotational torque of the rolling bearing for each bead. This makes it possible to measure the rotational torque of the rolling bearing with high accuracy without being adversely affected by the rotational torque of the spindle, and also to use each type of rolling bearing, such as seal material and grease. The excellent effect that the selection of the type including the above, the type including only the grease, and the type including neither the sealing material nor the grease is also possible is achieved.

[Brief description of drawings]

FIG. 1 is a front view including a partial cross section showing an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of an essential part of this embodiment, and FIG. 3 is a block diagram showing an electrical configuration of this embodiment. FIG. 4 is a time chart for explaining the phases of the reference pulse signal Ps and the puzzle signal Pm according to this embodiment, and FIGS. 5 and 6 are the phase differences δ1, δ2 and the load rotation torque f1, according to this embodiment. f
2 and the driving current values I1 and I2 are shown in FIG. 7, and FIG. 7 shows the rotation speed n and the output voltage Vt related to the selection operation of this embodiment.
It is a graph explaining the relationship with rg. 1 ... Bearing selection device, 2 ... Rolling bearing, 3 ... Holding device, 4 ... Spindle, 5 ... Bearing device, 6 ... Rotary encoder, 62 ... PLL circuit

Claims (1)

[Claims] Claim: What is claimed is: 1. A fixing means for fixing an outer ring of a rolling bearing to be sorted, a spindle in which a free end portion of the rolling bearing abuts on the inner ring, a static pressure air bearing for supporting the spindle, and a means for rotationally driving the spindle. A bearing selecting device comprising: a measuring device for measuring a rotating torque of a spindle; and a device for responding to an output of the measuring device and comparing the measured rotating torque with a predetermined reference torque.