JP2001170824A - Shrink fitting method for member and support axis having the member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shrink fitting method for a member capable of carrying out high precision assemblage by precisely positioning it against a jig without making contact with a standard surface required to maintain high precision against other members of the member to fit and install on a support axis. SOLUTION: A jig to hold a support axis is featured to have a bearing surface formed to be at required squareness against the support axis in its holding state and to install a member on the support axis by shrink fitting after making a parallel flat surface separated from the other member mounting standard surface of the member orthogonal in required precision against an axis of the support axis while there is a clearance between a hole and the support axis with the bearing surface and holding it in a shrink fitting method to install the member on the support axis by shrinkage of the member due to temperature fall by fitting the hole formed there against the support axis in a state of heating the member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for heating a member, fitting a hole formed in the member to a support shaft, and shrinking the member on the support shaft by contraction due to a temperature drop of the member. The present invention relates to a shrink fitting method for mounting.

[0002]

2. Description of the Related Art Conventionally, for example, a known shrink-fitting method has been used for assembling a polygon mirror mounting base of a laser beam printer and a motor rotating shaft for rotating the polygon mirror mounting base. That is, when assembling the support shaft and a member having a hole into which the support shaft is to be inserted, the member is heated to increase the hole diameter, and the support shaft is inserted into the hole by clearance fitting (play). Then, by cooling them to room temperature, the member is shrink-fitted to the support shaft (for example, Patent Registration No. 27).
In the invention of No. 18807, a method of shrink-fitting a polygon mirror mounting member and a motor shaft is disclosed).

[0003]

Here, since the parallelism between the support shaft and the mirror surface of the polygon mirror guarantees the product accuracy, this point must be sufficiently considered. This point will be specifically described in the assembled state shown in FIG. 2. Here, reference numeral 1 denotes a polygon mirror, which is fixed to the support shaft 2. Further, reference numeral 5 denotes a kingdom washer, 6 denotes a disc spring, and 3 denotes a polygon mirror 1 elastically via a disc spring 6.
Is a rotor having a magnet 8 provided on a yoke, 9 is a stator fixed to a substrate 10 corresponding to the rotor 7, and 4 is a bearing for the support shaft 2.
Then, the bearing 4 is fixed to the substrate 10, and in this state,
The polygon mirror 1 can rotate.

At this time, since the laser beam is reflected by a plurality of mirror surfaces 1B as a function of the laser beam printer, the plurality of mirror surfaces 1B must have a parallelism of 3 microns or less with respect to the support shaft 2. . For this reason, in the polygon mirror, the perpendicularity between the mirror surface 1B and the contact surface 1A (reference surface) with respect to the mounting base 3 is set to 1 micron or less. In this way, if the perpendicularity between the contact surface 3A of the mounting base 3 with the polygon mirror and the support shaft 2 is 1 micron or less, the parallelism between the support shaft 2 and the mirror surface 1B of the polygon mirror is guaranteed. .

However, in the above-described assembling method, since the error due to shrink fitting is not taken into account, the assembling method according to shrink fitting does not change the accuracy (squareness) between the support shaft 2 and the mounting base 3 as described above. , Parallelism) is not guaranteed. This is because, when the mounting base 3 is heated for shrink fitting, the contact surface 3A of the mounting base is brought into contact with the jig, and the contact surface with the metal causes scratches and dents on the mounting surface 3A.
This is because the accuracy of the method is reduced.

The present invention has been made based on the above circumstances, and an object of the present invention is to provide a criterion for maintaining high accuracy with respect to other members of a member fitted / mounted on a spindle. An object of the present invention is to provide a shrink-fitting method of a member which enables high-precision assembly without touching a surface and by accurately positioning the jig.

[0007]

In order to achieve the above object, according to the present invention, while a member is heated, a hole formed therein is fitted to a support shaft, and the member shrinks due to a temperature drop. In the shrink-fitting method of mounting the member on the support shaft, the jig for holding the support shaft is
It has a seating surface formed so as to have a required right angle with respect to the support shaft, and while there is a gap between the hole and the support shaft,
With respect to the axis of the support shaft, a plane parallel to the other member mounting reference plane perpendicular to the required accuracy with respect to the other member is brought into contact with and held against the seating surface, and then shrink-fitted. The member is mounted on the support shaft.

According to the present invention, in a state where the member is heated, the hole formed therein is fitted to the support shaft, and the member is mounted on the support shaft by contraction due to a temperature drop of the member. In the shrink fitting method, the jig holding the spindle is
In the holding state, the seating surface is disposed and formed at three equally-spaced positions around the axis so as to have a required right angle with respect to the shaft, and a gap is provided between the hole and the shaft. In the meantime, the other member mounting reference plane of the member orthogonal to the axis of the support shaft with required accuracy is measured at the positions corresponding to the three positions, and the measured value is fed back. Then, the height of the bearing surface is adjusted, and in this state, a parallel plane different from the reference surface is brought into contact with and held by the bearing surface, and then shrink-fitted to the support shaft. It is characterized in that the member is mounted.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to FIGS. 1 to 3
FIG. 1 shows a device for shrink fitting in a first embodiment of the present invention, and a subsequent assembled state of a member assembled thereby and other members positioned with respect to a reference surface of the member (conventionally, FIG. 2 is used).

[0010] The configuration shown in the conventional description is as follows.
They are denoted by the same reference signs as they are. Here, the motor shaft (support shaft) 2 as one of the workpieces is chucked by a collet chuck (jig) 17 provided on a base 19, and its mounting height is determined by a shaft height adjusting piece 18. Is set.
Further, a mounting base receiving member 16 having a seating surface 16 </ b> A orthogonal to the axis of the motor shaft 2 formed on the top surface as a seating surface of the jig is provided on a base 19. In the present embodiment, the receiving members 16 are separately arranged and formed at three equally-spaced portions around the axis of the motor shaft 2.
It is a pillar-shaped book.

Further, the mounting pedestal (member) 3 as the other side of the work is placed on the hot plate 1 via an appropriate chuck means (here, indicated by a click ball 15A).
5 is held in the cylindrical mounting hole 15B, but the reference surface 3A for positioning when attaching another member (for example, the polygon mirror 1) does not touch the hot plate 15 side. The hot plate 15 is attached to the upper and lower stages 12 via the heat insulating member 4, and when the stage 12 moves up and down along the vertical guide columns 11,
It is moved up and down with the mounting base 3. In the figure, reference numeral 13 is used.
Is compliance.

With such a configuration, if the accuracy of the perpendicularity of the seat surface 16A to the axis of the motor shaft 2 is high, the mounting base 3
The mounting pedestal 3 is orthogonal to the axis of the motor shaft 2 with required accuracy while there is a gap between the hole of the motor shaft 2 and the motor shaft 2.
A parallel plane 3B different from the reference plane 3A is
, The mounting base 3 can be accurately mounted on the motor shaft 2 by shrink fitting based on cooling. As a result, it is possible to obtain a shaft having a mounting pedestal as shown in FIG. 2 in which the other member mounting reference surface of the mounting pedestal is orthogonal to the axis with high accuracy.

Further, in the second embodiment shown in FIGS. 4 to 7, three regulators (for example, pneumatic cylinder mechanisms) 23A to 23A to which the seating surface is formed at the top and which can be adjusted up and down.
23C are equally spaced around the motor axis, and the non-contact sensor 20
A to 20C are prepared. And the non-contact sensor 2
At 0A to 20C, the height of the reference surface 3A of the mounting base 3 is measured, and the measured value is fed back to control the regulators 23A to 23C individually. Thereby, even if the plane 3B does not maintain the parallelism with respect to the reference plane 3A accurately, it is attached to the motor shaft 2 so that the reference plane 3A is positioned at an accurate right angle with respect to the axis of the motor shaft 2. After fitting the pedestal 3, shrink fitting can be realized. This situation is illustrated in FIGS. As a result, it is possible to obtain a shaft having a mounting pedestal as shown in FIG. 2 in which the other member mounting reference surface of the mounting pedestal is orthogonal to the axis with high accuracy.

In order to realize this shrink fitting, for example, as shown in FIG. 8, a controller for controlling the shrink fitting apparatus and a controller for controlling the temperature of the hot plate 15 may be provided. FIG. 9 shows a control flow of the shrink-fitting device according to the first embodiment. Here, the mounting base 3 is mounted on the hot plate 15 side, and the motor shaft 2 is mounted on the collet chuck 17. With it attached and placed, the stage 12 is lowered by automatic control,
The motor shaft 2 is inserted into the hole of the heated mounting base 3 to a required height. After the cooling step (about 5 seconds), the mounting base 3 is shrink-fitted to the motor shaft 2, and the mounting base 3 is separated from the stage 12 by moving up the stage 12. Finally, from the collet chuck 17, the mounting base 3 and the motor shaft 2,
Take out. As a result, the mounting base 3 can be mounted on the motor shaft 2 more accurately and quickly.

FIG. 10 illustrates a control system according to the second embodiment. Here, a distance sensor drive controller is prepared in addition to the above-described controller. Then, the regulators 23A to 23C are driven based on the measurement results of the non-contact sensors 20A to 20C.

Then, as shown in FIGS. 11 and 12, first, the master mounting base (member for reference)
Is placed on the support bar 21 of the jig 50, a non-contact sensor (distance sensor) is measured with respect to a reference surface (polygon attachment surface) 3A, and reset to zero. Thereafter, the mounting base 3 is set on the jig 50 (see FIG. 4). In addition,
The support bar 21 is attached to a gantry 22. In this state, the measured values of the non-contact sensor are fed back for controlling the regulators 23A to 23C, and the heights are adjusted respectively. Then, attach the mounting base 3 to the hot plate 15
Side, while chucking the motor shaft 2 to the collet chuck 17. Thereafter, similarly to the first embodiment, the stage 12 is lowered, and when the cooling process is completed, the stage 12 is raised, and the mounted mounting base 3 is mounted.
And remove the motor shaft 2 from the collet chuck,
The next task begins. As a result, the mounting base 3 can be mounted on the motor shaft 2 more accurately and quickly.

[0017]

EXAMPLE (Example 1) Here, a specific example realized in the first embodiment will be described. The parallelism (m / m) between the polygon mirror seating surface (that is, reference surface) 3A of the mounting base 3 and the jig-side seating surface 3B is 0.0005 mm or less. Also,
With the motor shaft 2 chucked by the collet chuck 17, the perpendicularity of the top 16A of the mounting base receiving member 16 is:
It is adjusted to 0.0005 mm or less. The heating temperature of the mounting base 3 by the hot plate 15 is as follows.

The shaft diameter of the motor shaft 2 here is 3 m.
It is 3.001 mm from m, and the hole diameter of the mounting base 3 = 2.990 mm
From 2.995 mm. Therefore, the shaft and hole are 0.005-0.
A tight fit of 011 mm results. Therefore, the mounting pedestal 3 is heated and the hole is expanded. The mounting base 3 here is made of brass,
The coefficient of thermal expansion is 200 × 10 ⁻⁷ , the shaft 2 is made of stainless steel, and the coefficient of thermal expansion is 110 × 10 ⁻⁷ .

The expansion of the hole is made larger than the maximum interference of 0.011 mm, and the gap is set to 0.003 mm at the time of shrink fitting. In this case, the expansion of the hole requires 0.014 mm. The heating temperature for this is as follows.

T = 0.014 / 2.990 / 200 × 10 ⁻⁷ + room temperature 25 degrees = 260 degrees As already described in the flow of FIG. 9, if the hot plate 15 first reaches 260 degrees (about 20 minutes) ), And push the mounting base 3 into the hole 15B. Then, the mounting pedestal 3 is held on the hot plate 15 by a click ball 15A (a structure for holding a steel ball with a spring). The support shaft 2 is held by a collet chuck 17.

With the hot plate 15, the mounting base 3 is about 30
When heated to 260 degrees in seconds, under the control of the controller,
The stage 12 descends. With the descent, the hole and the shaft come into contact, but the horizontal (X, Y) displacement is corrected by the compliance 13. Then, the plane 3 of the mounting base 3
B comes into contact with the top surface 16A of the receiving member 16, but at this time, the inclination is corrected by the compliance 13, and the two adhere closely. In this state, a required perpendicularity between the support shaft 2 and the mounting base 3 comes out.

Thereafter, the stage 12 is lowered by 1 mm,
The mm part is absorbed by the compliance 13. As a result, a load (about 1 kg) is applied to the mounting base 3 by the weight of the hot plate 15 and the heat insulating rod 14 and the like, and
The adhesion between B and top surface 16A is guaranteed. In this state,
By holding for about 5 seconds, heat is transmitted from the mounting pedestal 3 to the support shaft 2, and the temperature of the mounting pedestal 3 decreases and the temperature of the support shaft 2 increases by heat exchange. As a result, the hole diameter decreases and the shaft diameter expands. When shrink fitting is completed in this way, the stage 12 is raised, and the hot plate 15 is
Comes off. Then, finally, the collet chuck 17 is removed, and the mounting base 3 assembled to the support shaft 2 is taken out.

(Embodiment 2) Here, a case where the parallelism between the reference surface 3A of the mounting base 3 (mounting reference surface of the polygon mirror) 3A and the plane 3B in contact with the seat surface (top surface) 16A of the jig is not sufficient. An example is shown. Therefore, the shrink-fitting method according to the second embodiment is employed. That is, as a first step,
The deviation of the parallelism between the reference plane 3A and the plane 3B is measured. Next, as a second step, the deviation of the parallelism is corrected.

In the first step, as described above, the non-contact sensors 20A to 20C are used. It is appropriate to employ, for example, a non-contact distance laser sensor as the non-contact sensor. As described above, the measurement jig 50 measures the reference surface 3A at three points and initializes the measurement (FIG. 1).
1). Here, the parallelism between the reference surface 3A of the mounting base 3 and the plane 3B is 0.0001 mm. First, jig 5
Place the master mount on 0 and reset the sensor values to zero. As a result, when the mounting seat 3 is placed, the measured value thereof shows a deviation in parallelism. For example, sensor 2
0A measured value = 0.001mm, sensor 20B measured value = 0m
If m and the measurement value of the sensor 20C = −0.002 mm (a value of − means a low value), the parallelism is so deviated.

In the second step, a shrink fitting device shown in FIG. 5 is used. Here, regulators 23 </ b> A to 23 </ b> C are arranged corresponding to the positions of the support bars 21 of the measuring jig 50, and support the mounting base 3. And the sensor 20
Based on the measured values of A to 20C, the regulators 23A to
Control the height of 23C.

For example, based on the above-mentioned measured values, the regulator 23A is adjusted to be 0.001 mm lower, the regulator 23B is adjusted as it is, and the regulator 23C is adjusted to be higher by 0.002 mm. It is adjusted so that the perpendicularity of the contact surface with the support shaft 2 is 0.0005 mm or less.)

Thus, even if the parallelism between the reference plane 3A and the plane 3B is originally not sufficient, in the step of mounting the mounting base to the shaft, the reference surface of the support shaft 2 and the mounting base 3 chucked by the collet chuck 17 is used. The perpendicularity with 3A is guaranteed. Subsequent processing is the same as in the first embodiment.

Although the hot plate is used for heating the mounting base 3 in the embodiment of the present invention, electromagnetic induction heating using an electromagnetic induction coil may be used. This is slightly advantageous in that the heating time (about 5 seconds) can be shortened.
The shrink fitting of the present invention can be realized not only by heating the mounting pedestal but also by cooling the support shaft, and also by heating the mounting pedestal and cooling the support shaft.

[0029]

According to the present invention, as described above, a hole formed therein is fitted to a spindle while the member is heated, and the member is shrunk by a temperature drop of the member, and the member is heated. In the shrink-fitting method of mounting the member on a shaft, the jig holding the support shaft has a seat surface formed to have a required right angle with respect to the support shaft in the holding state, While there is a gap between the hole and the support shaft, a plane parallel to the axis of the support shaft, which is orthogonal to the axis of the support shaft with a required accuracy, is different from the other member mounting reference surface of the member, And then mounting the member on the support shaft by shrink fitting.

Accordingly, the member can be mounted on the support shaft by shrink fitting while maintaining a required perpendicularity to the support shaft without damaging the reference surface for attaching another member to the member.

Further, according to the present invention, when the member is heated,
In the shrink-fitting method of fitting the hole formed therein to the support shaft and mounting the member on the support shaft by shrinkage due to temperature drop of the member, the jig holding the support shaft is In the holding state, the seat has a seating surface arranged and formed at three equally divided places around the axis so as to have a required right angle with respect to the spindle, and a gap is formed between the hole and the spindle. Meanwhile, the other member mounting reference plane of the member orthogonal to the axis of the support shaft at a required accuracy is measured at positions corresponding to the three positions, and the measured value is fed back. The height of the seating surface is adjusted, and in this state, a parallel plane different from the reference surface is brought into contact with and held against the seating surface, and then shrink-fitted to the support shaft. It is characterized by mounting members.

Therefore, even if the parallelism between the plane of the member that is in contact with the jig and the reference surface for attaching another member to the member is not sufficiently ensured, the burning is performed without damaging the reference surface for attaching another member. The fitting allows the member to be mounted on the support shaft while securing a required perpendicularity to the support shaft. This is effective in reducing the manufacturing cost of the member.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a shrink fitting device according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional side view showing a specific example of an object to be shrink-fitted.

FIG. 3 is a vertical sectional side view of a main part.

FIG. 4 is a configuration diagram of a jig showing a measuring unit according to a second embodiment of the present invention.

FIG. 5 is a configuration diagram showing a part of the shrink fitting device.

FIG. 6 is a block diagram showing the entire shrink fitting device.

FIG. 7 is a block diagram showing a usage mode.

FIG. 8 is a block diagram showing a control system.

FIG. 9 is a flowchart illustrating a shrink-fitting process according to the first embodiment.

FIG. 10 is a block diagram illustrating a control system according to the second embodiment.

FIG. 11 is a flowchart showing a measurement process.

FIG. 12 is a flowchart showing a shrink fitting process.

[Explanation of symbols]

 Reference Signs List 1 polygon mirror (other member) 2 motor shaft (support shaft) 3 mounting base 3A other member mounting reference surface 3B plane (contact surface) 4 bearing 5 kinsei washer 6 disc spring 7 motor yoke 8 motor magnet 9 motor stator 10 substrate 11 guide Support 12 Vertical stage 13 Compliance 14 Insulating rod 15 Hot plate 15A Click ball 15B Hole 16 Mounting base receiving member 16A Top surface (Seat surface) 17 Collet chuck (Jig) 18 Height adjustment piece 19 Base 20A to 20C Non-contact sensor 21 Support rod 22 Mount 23A-23C Regulator

Claims (4)

[Claims] 1. A shrink-fitting method in which a hole formed therein is fitted to a spindle while the member is heated, and the member is attached to the spindle by shrinkage due to a temperature drop of the member. The jig for holding the support shaft has a seat surface formed so as to have a required right angle with respect to the support shaft in the holding state, and a gap is provided between the hole and the support shaft. Meanwhile, a plane parallel to the axis of the support shaft, which is different from the other member mounting reference surface of the member orthogonal to the required accuracy, is brought into contact with and held against the seating surface. A method of shrink-fitting a member, wherein the member is mounted on the support shaft by shrink-fitting. 2. A shrink fitting method in which a hole formed therein is fitted to a spindle while the member is heated, and the member is attached to the spindle by shrinkage due to a temperature drop of the member. The jig for holding the support shaft has a seating surface arranged and formed at three equally-spaced positions around the axis so that the jig in the holding state has a required right angle with respect to the support shaft, While there is a gap between the hole and the support shaft, the other member mounting reference plane of the member orthogonal to the axis of the support shaft with required accuracy, at a location corresponding to the three locations, The height is measured, the measured value is fed back, the height of the seating surface is adjusted, and in this state, a parallel plane different from the reference surface is brought into contact with and held against the seating surface. Then, by shrink fitting,
A method of shrink-fitting a member, comprising mounting the member on the spindle. 3. A spindle having the member obtained by the shrink-fitting method of the member according to claim 1. 4. A spindle having the member obtained by the shrink-fitting method for the member according to claim 2.