JPH0832146B2 - Press-fitting device for shaft member - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is applied, for example, when a shaft of a spindle motor is press-fitted into a hub or a rotor, and a shaft member is provided with a hole capable of being tightly fitted in the shaft member. The present invention relates to a press-fitting device for a shaft member that press-fits into the hole of a member that has the shaft member.

[Conventional technology]

Conventionally, a press-fitting device for a shaft member is provided movably in a uniaxial direction on a base and is provided so as to oppose the press head fed in the uniaxial direction by a feed screw or a hydraulic device in the uniaxial direction to support a work. There is a work supporting part for performing the work. Then, in the work supporting part, one of the shaft member and a member having a hole that can be tightly fitted to the shaft member, in the axial direction of the shaft member, and if the member having the hole. While fixing the shaft center of the hole in parallel to the one axis direction, the other of the members having the shaft member and the hole with respect to the fixed one, the shaft member and the hole of the member are substantially coaxial As described above, the press head is mounted on the other side, and the other side is pushed by the press head to a predetermined position with a constant force or a constant speed in a constant direction in which the shaft member and the member having the hole approach each other. Thus, the shaft member is relatively press-fitted into the hole of the member having the hole.

[Problems to be Solved by the Invention]

However, in the above-described conventional press-fitting device, the shaft member and the member having the hole are both fixed to the support member or the press head, and the shaft member is press-fitted into the hole of the member having the hole at a stroke. Therefore, if there is a slight misalignment between the shaft member and the member having the hole, there is a problem that the two members will be galled or press-fitted in a bent state, resulting in poor press-fitting accuracy. It was

An object of the present invention is to provide a shaft member press-fitting device capable of press-fitting a shaft member into a hole of a member having a hole with high accuracy without being press-fitted in a state of being galled or bent. .

[Means for solving the problem]

In order to achieve the above object, a press-fitting device for a shaft member according to the present invention is provided with a base, and has one of a shaft member having a shaft center in one axial direction and a member having a hole closely fitted to the shaft member. A work supporting portion that holds the lower end position of the shaft center at a predetermined height and elastically supports the tilting in a radial direction; and a press that is movably provided in the base in a uniaxial direction and is opposed to the work supporting portion in a uniaxial direction. A head; and a servo actuator that gives a reciprocating feed to the press head in a uniaxial direction toward the work supporting portion and repeats a forward movement of a fixed dimension and a backward movement shorter than the fixed dimension; a work supporting portion and a press head; The other one of the shaft member and the member movably held in the axial direction is pressed by a press head to be press-fitted into one of the shaft member and the member.

[Action]

One of the shaft member and the member having the hole, which is pressed by the press head, and the other of the shaft member and the member having the hole, which is tiltably supported by the work supporting portion, are substantially coaxial. Will be placed.

At the time of press fitting, the press head is sent in the uniaxial direction by the servo actuator, and one of the shaft member and the member having the hole is not pressed all at once to the press fitting end position as in the conventional case, but a load is applied. ， Pressing gradually while repeating unloading. Therefore, relatively, the shaft member is press-fitted stepwise into the hole of the member having the hole.
At this time, since the other of the shaft member supported by the work supporting portion and the member having the hole is tiltably supported by the work supporting portion, the hole of the member having the shaft member having the hole is formed. Even if the press-fitting is relatively inclined or eccentric with respect to the press-fitting, the tilt or the eccentricity is tilted so that the press-fitting resistance becomes constant irrespective of the circumferential position at each stage of the press-fitting by the reciprocating movement of the press head. That is, it is reliably absorbed by the tilting of the other of the member having the shaft member and the hole that tilts so that the shaft center of the shaft member coincides with the shaft center of the hole. Therefore, the shaft member is press-fitted into the hole of the member having the hole with high precision and coaxiality.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

FIG. 2 is a view of a press-fitting device for a shaft member of a spindle motor as an embodiment of a press-fitting device for a shaft member according to the present invention, as seen from a direction orthogonal to the press-fitting direction.

In FIG. 2, reference numeral 1 is a base having a horizontal portion 1a and a vertical portion 1b, and a press head 3 is provided on the vertical portion 1b of the base 1 via a linear bearing 2 so as to be vertically movable. . The press head 3 has a pressing portion 3a having a pressing surface extending in the horizontal direction at the lower end, and a ball nut portion 3b at the upper end. The support unit 4 is provided on the support portion 1c provided on the vertical portion 1b and extending in the horizontal direction,
The ball nut portion 3b is screwed onto a ball screw shaft 5 supported rotatably therethrough but immovable in the axial direction. Therefore, the press head 3 is fed in the vertical direction indicated by X in the drawing in accordance with the rotation of the ball screw shaft 5. The ball screw shaft 5 is provided with a timing pulley 6, a timing belt 7 and a timing pulley 8
It is rotationally driven by a servo actuator 10 such as a servo motor fixed to the support 9. This servomotor is controlled by a control circuit (not shown) to rotate the ball screw shaft 5 through the timing pulley 6, the timing belt 7 and the timing pulley 8 to cause the press head 3, as shown in FIG. Stroke S1 descending,
Stroke S2 rises (S1> S2), stroke S1 falls,
Increase of stroke S2, ... (eg stroke S1 = 100μ
m, stroke S2 = 50 μm).
That is, the press head 3 is caused to move while vibrating slightly in the axial direction X.

A work supporting portion 11 is provided on the horizontal portion 1a of the base 1 so as to face the press head 3 in the vertical direction X, and the respective shaft centers of the work supporting portion 11 and the press head 3 are equal to each other. I am doing it. The work supporting portion 11 has a substantially cylindrical shape extending in the vertical direction, and has a plurality of protruding portions 12a, 12a, ...
Support portion 12 and an annular shape having a substantially rectangular cross section, the protrusions 12a, 12a,
, And a second support portion 13 having shafts 13a, 13a, ... Which extend downward in the vertical direction. Then, after the shaft 13a of the second support portion 13 is inserted into the through hole of the protrusion 12a with a predetermined gap, the shaft 13a is then inserted.
Is retained by a retaining ring 14 attached to the shaft end.
A shaft 13a is provided between the first support 12 and the second support 13.
The coil springs 15 having a proper natural spring length and a predetermined natural length are contracted by a fixed length in a mounted state. Therefore, the second support portion 13 keeps horizontal when there is no load or when the load acts evenly, while it tilts according to the load when an unbalanced load acts, and further, the shaft 13a and the protruding portion It can move in a substantially horizontal direction within a predetermined range (for example, about 0.5 mm) determined by a gap formed between the through holes of 12a. A reference portion 12b is provided at the center of the upper surface of the first support portion 12, and the reference portion 1b is provided.
2b has a gentle convex surface, and vertically supports the work placed on the upper surface of the second support portion 13 at a predetermined vertical position. Since the reference portion 12b comes into contact with the work in a small area at the time of press fitting, it does not hinder the tilting of the second support portion 13. In this way, the work supporting portion 11 supports the work placed on the second supporting portion 13 when the press-fitting is performed, but is tiltable, but immovable in the axial direction.

The second support portion 12 of the work support portion 11 has a shaft 21
A flange 22 fitted and fixed to the end of the shaft 21 and extending in the radial direction; an annular member 24 rotatably supported by the shaft 21 via a bearing 23 and having an outer peripheral surface coaxial with the shaft 21; The shaft member 20 provided with the fixing shaft 22 and the fixing flange 22 are brought into contact with the upper surface of the second supporting portion 13,
The outer peripheral surfaces of 21 and the annular member 24 are placed while being held substantially concentrically with the press head 3.

Above the shaft member 20 in the vertical direction, there are holes 31 and 32 that can be tightly fitted to the upper end of the shaft 21 of the shaft member 20 and the annular member 24, and the magnet 33 as a rotor is attached to the inner peripheral surface. The shaft center of the substantially cylindrical member is supported by a supporting member (not shown) that is movable in the vertical direction, and the press head 3 and the shaft member are
It is supported coaxially with 20. Since the support member (not shown) supports the member 30 so as to be movable in the vertical direction, the press-fitting is not hindered. The member 30 constitutes a spindle motor together with the shaft member 20 and constitutes the rotation side of this spindle motor. The upper end of the member 30 is pressed by the press head 3.

In addition, the press head 3 is
And a distance measuring sensor 17 for detecting a vertical distance between the detected portion 16 provided on the second supporting portion 13 and the second supporting portion 13 are mounted, and the press head 3 of the press head 3 is detected based on the distance measuring data detected by the distance measuring sensor 17. Since the feed stop position is determined, the member 30 is a shaft member.
Accurately press fit into 20 predetermined axial positions. The second
The distance of the distance measuring sensor 17 shown from d in the drawing from the axial center of the press head 3 is set to be sufficiently small so that a problematic distance measuring error does not occur.

In the above structure, the member 30 is press-fitted into the shaft member 20 as follows. That is, as shown in FIG. 2, the flange 22 of the shaft member 20 is placed on the second support portion 13 of the work support portion 11 to support the shaft member 20 on the work support portion 11,
The member 30 is supported by the support member (not shown). As a result, the shaft member 20 and the member 30 are arranged substantially coaxially.
Then, the servo actuator 10 is operated to move the press head 3 so that the press head 3 contacts the member 30.
The close fitting between the hole 31 of the shaft member 30 and the shaft 21 of the shaft member 20 is slightly started, and the shaft member 20 is pressed downward through the member 30 by the start of this fitting, so that the shaft member 20 moves to the first position. 1 support 12
It is lowered at a predetermined high speed until it comes into contact with the reference portion 12b (see area a in FIG. 1). Reference part 12b of the shaft member 20
The shaft member 20 is supported in the axial direction by the first supporting portion 12 by the contact with the shaft member 20. Then, the servo actuator 10 is actuated to give the press head 3 a slight reciprocating motion (see region b in FIG. 1) consisting of repeated lowering of 100 μm and rising of 50 μm. That is, the press head 3 is moved down while slightly reciprocating. Then, the press head 3 has the member 30.
Instead of press-fitting to the press-fitting end position in one stroke at a time as in the past, step by step with a small stroke of approximately 50 μm while repeating loading and unloading, and stepping the hole 31 of the member 30 to the shaft 21 To fit them in the axial direction. At the time of this press-fitting, the member 30 is inclined or eccentric with respect to the shaft member 20, and more specifically, the shaft center of the hole 31 of the member 30 is the shaft member.
Even if the shaft member 20 is inclined or eccentric to the shaft center of 20 and is press-fitted, the shaft member 20 is tiltably supported by the work supporting portion 11 as described above. At each stage of press-fitting by the slight reciprocal movement of the press head 3, the press-fitting resistance is tilted so that the press-fitting resistance is constant regardless of the circumferential position.
That is, the tilting of the shaft member 20 that tilts so that the shaft center of the shaft member 20 and the shaft center of the hole coincide with each other allows immediate and reliable absorption. Therefore, the shaft 21 of the shaft member 20 is pressed into the hole 31 of the member 30 with high precision and coaxiality. Further, since the press-fitting margin does not vary depending on the circumferential position, the member 30 is not distorted into an elliptical shape by the press-fitting. In addition, even if the hole 32 and the annular member 24 are closely fitted, the hole 31 and the shaft
The description is omitted because it is similar to the close fitting with 21. Further, the pressure input can be managed by detecting the current value of the servo motor serving as the servo actuator 10 in the illustrated example.

In the above embodiment, the shaft member 20 includes the shaft 21, the fixing flange 22, the bearing 23, the annular member 24 and the stator 25,
The case where the member 30 having the hole, which constitutes the main part of the spindle motor, is provided with the hub 34, the bearing 35 and the magnet 33, and which mainly constitutes the main part on the rotation side of the spindle motor is illustrated. It goes without saying that the member having the hole that can be tightly fitted in the shaft member is not limited to that of the above-mentioned embodiment. For example, the shaft member is the shaft of the above-mentioned embodiment.
On the other hand, the member having the hole 21 may be the fixing flange 22 of the above embodiment. Further, the member 30 having a hole is supported by the work supporting member 11, and the shaft member 20 is pressed by the press head 3.
You may press at. Further, the strokes S1 and S2 of the reciprocating motion are not limited to the combination of S1 = 100 μm and S2 = 50 μm, and an appropriate size is selected. Further, the work supporting portion is capable of inclining a supporting shaft member or a member having a hole, provided that the work supporting portion does not move in one axial direction,
The present invention is not limited to the work supporting portion 11 of the above embodiment.

In the above embodiment, a servo motor is used as the servo actuator 10, and the ball screw shaft 5 as the feed screw is rotationally driven by this servo motor to press the head 3.
However, the servo actuator is not limited to the servo motor, and may be a combination of a fluid cylinder and a servo valve, for example.

〔The invention's effect〕

The shaft member press-fitting device of the present invention is movably provided in the base in a uniaxial direction, and is fed while being reciprocally moved in the uniaxial direction by a servo actuator to form a shaft member and a hole tightly fitted to the shaft member. A press head for pressing one of the members having the shaft head and the other of the members having the hole, which are provided in the base so as to face the press head in the uniaxial direction, can tilt. Since the work support portion that supports the shaft member immovably in the axial direction is provided, it is possible to relatively press fit the shaft member into the hole of the member having the hole capable of tightly fitting the shaft member while preventing eccentricity. Therefore, it is possible to press-fit the shaft member into the hole of the member having the hole with higher accuracy than the conventional method.

[Brief description of drawings]

FIG. 1 is an explanatory view of reciprocating movement of a press head of an embodiment of a press-fitting device for a shaft member according to the present invention, and FIG. 2 is a view for explaining an embodiment of a press-fitting device for a shaft member according to the present invention from a direction orthogonal to a press-fitting direction. It is the figure seen. 1 ... Base, 3 ... Press head, 10 ... Servo actuator, 30 ... Members having holes, 31, 32 ... Holes, X ... Vertical direction (uniaxial direction).

Claims (1)

[Claims] 1. One of a shaft member 20 provided on a base 1 and having a shaft center in one axial direction and a member 30 having holes 31 and 32 that are closely fitted to the shaft member 20 is provided at a lower end position of the shaft center. And a work support portion 11 that elastically supports the work piece 11 at a predetermined height and is tiltable in the radial direction, and a press that is provided on the base 1 so as to be movable in the uniaxial direction and that opposes the work support portion 11 in the uniaxial direction. A head 3 and the work support portion in the uniaxial direction on the press head 3.
A servo actuator 10 for feeding a reciprocating motion that repeats a forward movement of a fixed dimension and a backward movement shorter than the fixed dimension toward 11, and is provided between the work support section 11 and the press head 3 in the uniaxial direction. The other of the shaft member 20 and the member 30 movably held is pressed by the press head 3,
A press-fitting device for a shaft member, wherein the press-fitting device is adapted to press-fit into one of the shaft member 20 and the member 30.