JP2871508B2 - Laser welding method and apparatus for rotor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for laser welding for integrating a rotor and a rotary shaft by welding.

[0002]

2. Description of the Related Art Heretofore, it has been general to assemble a rotor that a rotary shaft is press-fitted into an insertion hole formed in the center of the rotor and fixedly integrated. However, when the rotor is incorporated into the motor, it rotates at high speed around the rotation axis.
Balance is important to ensure smooth high-speed rotation. For example, if the rotation axis is extremely slightly bent and the balance is not maintained, it may cause center runout. However, when press-fitting the rotating shaft, a large load is applied to the rotating shaft in the longitudinal direction and the rotating shaft is inserted into the insertion hole of the rotor. This caused the rotor to oscillate.

[0003]

The problem to be solved by the present invention is as follows.
An object of the present invention is to eliminate the press-fitting work that causes the distortion of the rotating shaft, and to enable the rotating shaft to be accurately fixed to the center of the rotor.

[0004]

According to a first aspect of the present invention, there is provided a method for laser welding a rotor (1), comprising the steps of: "rotating a shaft (5) through an insertion hole (2) formed at the center of the rotor (1); ) Is inserted with an intermediate fit or a gap fit, and a laser beam (4) is applied to a boundary portion (a) between the hole edge of the insertion hole (2) and the rotation axis (5) to generate the boundary portion (a).
And the hole edge of the rotor (1) and the rotating shaft (5) are integrated at the boundary portion (a). "

[0005] According to this, the rotor (1) and the rotating shaft (5) are inserted through the "intermediate or gap" so that the rotor (1) and the rotating shaft (5) are inserted.
The insertion of the rotating shaft (5) into the insertion hole (2) of (1) can be done without applying force, not by press-fitting, or with a very small force,
There is no distortion of the rotating shaft (5) during insertion. Then, the rotating shaft (5) inserted in such an undistorted state and while maintaining the hammer-eye state is inserted into the hole edge of the insertion hole (2) formed in the center of the rotor (1) by the laser beam (4). Since welding is performed, the rotor (1) and the rotating shaft (5) are integrated with high balance performance around the rotating shaft (5), and when incorporated into the motor (M), the rotor (1) is rotated. Even when rotating at high speed around (5), there is no occurrence of center runout.

According to a second aspect of the present invention, a welding projection (27) is provided on the edge of the hole of the rotor (1), and the welding projection (27) is provided.
Is irradiated with a laser beam (4) to melt the projection (27) for welding, and the projection (27) for welding and the rotating shaft (5) are integrated by welding ”. According to this, the welding projection (27) projecting from the hole edge of the rotor (1) is melted by the irradiation of the laser beam (4) and welded to the rotating shaft (5), and the rotor ( Distortion due to welding is prevented from occurring in the main body portion of 1), and the rotation balance performance of the rotor (1) is not impaired.

A third aspect of the present invention is that a spline groove (28) substantially parallel to the center line is formed in the inner peripheral surface of the insertion hole (2) or the outer peripheral surface of the rotary shaft (5). Features. According to this, the contact area between the insertion hole (2) and the rotating shaft (5) is reduced, the insertion pressure becomes smaller even in the case of plus fitting in the intermediate fit, and the distortion at the time of inserting the rotating shaft (5) is reduced. The occurrence can be completely eliminated.

According to a fourth aspect of the present invention, "a welded portion (2a) to be welded to both surfaces of the rotor (1) is formed symmetrically with respect to a center point of the rotor (1). According to this,
It is released because the welded portion (2a) becomes a factor that disturbs the rotational balance.

Claim 5 of the present invention is a specific apparatus (A) for carrying out the method, wherein “the laser generator (6), the rotor (1) and the rotor (1) are provided with intermediate or free-fitting. A laser irradiator (3) for irradiating a laser beam (4) generated by a laser generator (6) to a boundary portion (a) of the inserted rotary shaft (5), a laser generator (6) and a laser irradiator (3) and a laser transfer member (8) connecting, it is composed out with rotor (1) work table for placing a (9), a laser irradiation device
(3) on both sides of the rotor (1) and inside the rotor (1)
A plurality of laser transformers are arranged point-symmetrically at the center point.
A spa member (8) is generated by a laser generator (6).
Laser beam (4) almost equally to each laser irradiation device (3)
Is configured to be branched so as to be transmitted to

According to this, a laser beam (4) generated by a laser generator (6) passes through a laser transfer member (8) such as a glass fiber and enters a laser irradiator (3). And the boundary between the rotor (1) and the rotating shaft (5) (a)
And welds the boundary part (a) partially. As a result, the rotor (1) and the rotating shaft (5) are integrated without breaking the rotational balance. The rotor (1) and the rotating shaft (5)
Does not need to be press-fitted as in the conventional "Shrink-fit", especially for small motors (M), where the rotary shaft (5) is inserted. Hole
(2) It is possible to eliminate the occurrence of distortion at the time of insertion into the motor, and it is very effective for mass production of small motors (M).

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a block circuit diagram of a laser processing apparatus (A) according to the present invention. A laser generator (6) includes a yag rod (YAG rod) (11) and shutters (12) and (13) installed on both sides thereof.
And an excitation lamp (14) for applying light to the YAG rod (11)
And a power supply (7) for applying an excitation lamp (14), and an excitation lamp
Housing (15) for housing (14) and YAG rod (11)
A cooler (16) for cooling the housing (15);
A total reflection mirror (19) installed behind the middle and left shutters (12) and an output mirror arranged in front of the shutter (13)
(20). In front of the output mirror (20),
One or more (in this embodiment) branch mirror (10) and one total reflection mirror (17) are provided, and the branch mirror (10) is provided.
The laser beam (4) reflected by the total reflection mirror (17) is controlled by an optical system (18) and input to a transfer member (8).

When the number of split mirrors (10) is 3 and the number of total reflection mirrors (17) is 1 as in this embodiment, each split mirror (10)
The laser beam (4) reflects 25% of the entire laser beam (4), and the remaining 25% is reflected by the final total reflection mirror (17). The laser beam (4) entering each optical system (18) is reflected. ) Are formed to be uniform. (That is, the laser irradiation device
When there are N pieces of (3), the laser beam (4) emitted from the output mirror (20) is divided into N and output. The laser beam (4) is, for example, continuous wave, pulsed, Q
It is output by a method such as switch pulse oscillation or single mode.

The optical system (24) of the laser irradiation device (3) is formed by combining, for example, a single lens, a doublelet lens, a triplelet lens, a plano-convex lens, a cylindrical lens, and other various lens systems. The laser generator (6) and the laser irradiator (3) are connected by a laser transfer member (8), and the laser beam (4) is
Input to (3).

Reference numeral (26) denotes a mirror incorporated in the optical system (24) of the laser irradiation device (3), which totally transfers the laser beam (4) input from the transfer member (8) into the laser irradiation device (3). It is designed to reflect.

An insertion hole (2) is formed through the center of the rotor (1), and a rotary shaft (5) is inserted through the insertion hole (2). In the present invention, in order to prevent excessive force from being applied when the rotary shaft (5) is inserted into the insertion hole (2), "intermediate fit or clearance fit" is selected as the fitting between them. However, if the clearance between the insertion hole (2) and the rotating shaft (5) is large in the case of "Skip-on fit", the rotation balance will be obtained when the rotor (1) and the insertion hole (2) are integrated by welding. However, this is not preferable because it may worsen, but is practically acceptable.
In the case of "middle fit" plus fitting, the press-fit state is obtained, but the press-fit allowance is small, and even in the case of the rotary shaft (5) for a small motor (M), the press-fit distorts the rotary shaft (5). Such a state does not occur, and conversely, even if a gap is formed between them, it is not so large as to impair the rotational balance of the rotor (1). Ideally, from the viewpoint of rotational balance, it is preferable that the fitting of the rotary shaft (5) and the insertion hole (2) is almost zero. or,
In order to reduce the insertion resistance of the rotating shaft (5) into the insertion hole (2), a spline groove (28) parallel to the center line of the rotating shaft (5) may be formed.

The rotor (1) into which the rotating shaft (5) is inserted is mounted and fixed on a work table (9). In the present embodiment, the rotary shaft (5) is held on the work table (9) by using center holes formed in the centers of both ends of the rotary shaft (5). (2
1) is a device for holding both ends of the rotating shaft (5). The work table (9) may be installed on a moving means (10). The moving means (10) is, for example, an XY table or a conveyor, and in that case, the rotor (1) is connected to the moving means (10).
For example, and intermittently moves or moves in the XY directions (XYZ directions are also possible). Conversely, the rotor (1) is not installed on the conveyor belt or the XY table as described above,
It is of course conceivable that the worker may be manually placed on the work table (9) in a batch manner.

Next, the operation of the present invention will be described. First, the rotor (1) with the rotating shaft (5) inserted
(9) Installed on the laser generator (6)
(14) is turned on, and a laser beam (4) as a light source is generated by the yag rod (11). Since the principle of generation of the laser beam (4) is known, its explanation is omitted. Yag rod (11)
The laser beam (4) generated by the laser beam enters the laser irradiation device (3) through the output mirror (20) and the transfer member (8), is reflected by the total reflection mirror (26), and is further reflected by the optical system (24). In addition, the light reaches the boundary portion (a) between the rotor (1) and the rotating shaft (5) through the glass fiber (17). The welding laser beam (4) is focused on the boundary portion (a), and the focused portion is heated and melted instantaneously or in a short time to perform spot welding. The size of the spot welding depends on the light condensing area, but in the case of the present embodiment, the diameter is 1 mm or less (1 to 0.1 mm).
It is about 8 mm. In addition, the welding portion (2a) is formed on both surfaces of the rotor (1), but is usually formed in point symmetry with respect to the center point of the rotor (1) so as not to lose rotational balance. . The welding portion (2a) is formed at least one at a time on one side, but may be plural. (In this embodiment, left and right 2
It is part by part. Alternatively, a pair of laser irradiation devices (3) may be installed before and after the rotor (1), and welding may be performed at a plurality of locations at predetermined intervals while rotating the rotor (1).

When the rotor (1) thus formed is incorporated into the motor (M) and rotated at high speed, the rotating shaft (5) has no distortion and is accurately mounted at the center of the rotor (1). Because of this, there is no occurrence of runout.

The rotor (1) of the present invention may be an integral one as shown in FIG. 2, but may be a rotor obtained by laminating a plurality of punched members by pressing. Also, the rotor
A projection (27) for welding is protruded from the edge of the insertion hole (2) of (1), and the welding projection (27) is irradiated with a laser beam (4) to irradiate the welding projection (27). ) May be melted, and the welding projection (27) and the rotating shaft (5) may be integrated by welding. The welding protrusion (27) may be one that simply protrudes from the hole edge as shown in FIG.
Welding protrusion in recess (2b) so that it is in contact with the outer surface of
(27) may be protruded. In this way, a projection (27) for welding is protruded from the edge of the hole of the rotor (1), and the projection (27) for welding is irradiated with a laser beam (4) and welded to the rotating shaft (5). Rotor (1)
Prevents the main body from being distorted by welding,
There is no loss of the rotational balance performance of the rotor (1). In this case, the welding projections (27) are provided point-symmetrically with respect to the center of the rotor (1).

The irradiation time and output of the laser beam (4) are set in advance and controlled by a CPU (not shown). When the processing by the laser beam (4) is completed, the work table (9) is moved and replaced with the next unprocessed rotor (1), and the spot welding operation is repeated.

Note that the laser welding is performed in an assist gas atmosphere by injecting an assist gas into a welding position (2a) of the rotor (1). As the assist gas, for example, oxygen gas is used as an active gas, and nitrogen, argon gas or the like is generally used as an inert gas.

[0022]

According to the method of the present invention, since the rotor and the rotating shaft are fitted to each other with an intermediate or clearance fit, the rotating shaft is inserted into the rotor without applying any force or with a very small force. It does not cause distortion of the rotating shaft during insertion. And the laser beam is radiated and welded to the boundary between the rotor and the rotating shaft assembled in this way, so that the rotor is integrated with high rotation balance performance to the rotating shaft. No center runout of the rotor occurs. Further, when spot welding is performed using a welding projection projecting from the hole edge of the rotor, distortion due to welding of the main body of the rotor is prevented, and the rotation balance performance of the rotor is not impaired. Further, when a spline groove substantially parallel to the center line is formed on the inner peripheral surface of the insertion hole or the outer peripheral surface of the rotating shaft, the insertion can be performed with a small force even in the case of positive fitting of the intermediate fit. When the welded portion is formed point-symmetrically with respect to the center point of the rotor, the welded portion does not cause a loss of rotational balance, and a well-balanced high-speed rotation is guaranteed. Thus, by employing the method and apparatus of the present invention, a thin rotating shaft can be quickly and accurately attached to the center of a small rotor, and mass production of small motors becomes possible.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram of a laser processing apparatus according to the present invention.

FIG. 2 is a sectional view of a rotor according to the present invention.

FIG. 3 is a cross-sectional view of FIG. 2;

FIG. 4 is an enlarged partial cross-sectional view of one embodiment of a welding portion according to the present invention.

FIG. 5 is an enlarged partial sectional view of another embodiment of the welding portion according to the present invention.

FIG. 6 is an enlarged partial sectional view of still another embodiment of a welding portion according to the present invention.

FIG. 7 is a front half-sectional view of a motor incorporating a rotor manufactured according to the present invention.

FIG. 8 is an axial half-sectional view of a motor incorporating a rotor manufactured according to the present invention.

[Explanation of symbols]

 (1) Rotor (2) Insertion hole (3) Laser irradiation device (4) Laser beam (5) Rotation axis (A) Boundary part

Claims (5)

(57) [Claims] 1. A rotary shaft is inserted through an insertion hole formed in the center of a rotor with an intermediate fit or a clearance fit, and a laser beam is applied to a boundary portion between a hole edge of the insertion hole and the rotary shaft to form the boundary. A laser welding method for a rotor, characterized in that a portion of the rotor is melted and a hole edge of the rotor and a rotating shaft are integrated at the boundary portion. 2. A welding projection is projected from the edge of the hole of the rotor, and the welding projection is irradiated with a laser beam to melt the welding projection. The laser welding method for a rotor according to claim 1, wherein the rotor is integrated by welding. 3. The rotor according to claim 1, wherein a spline groove substantially parallel to the center line is formed in an inner peripheral surface of the insertion hole or an outer peripheral surface of the rotating shaft. Laser welding method. 4. The laser welding of a rotor according to claim 1, wherein the welding portions to be welded to both surfaces of the rotor are formed symmetrically with respect to a center point of the rotor. Method. 5. A laser generator, a laser irradiator for irradiating a rotor and a laser beam generated by the laser generator to a boundary portion of a rotary shaft inserted into the rotor with intermediate or gap fit, a laser generator, and a laser. It is composed of a laser transfer member connecting the irradiation device and a work table on which the rotor is placed . The laser irradiation device is located on both sides of the rotor and at the center of the rotor.
Are arranged symmetrically in a point
The laser member emits the laser beam generated by the laser generator.
A laser processing apparatus for a rotor, which is branched so as to transmit the laser beam to a laser irradiation apparatus substantially uniformly .