JPS6361117B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a welding method and apparatus for fixing a hub and spoke plates in a steel plate wheel for a motorcycle. In conventional motorcycle wheels, not only the front wheel but also the rear wheel, which is the driving wheel, is elastically connected between the hub and the rim by elastic wires called spokes. However, this connection structure using elastic wire requires complicated steps in manufacturing the wheel, and is extremely inefficient and time-consuming. In view of these drawbacks, a steel plate wheel has been proposed in which the hub and rim are directly welded using a steel plate called a spoke plate, but when welding the spoke plate and the hub, welding distortion caused by the heat caused This causes a phenomenon in which the inner peripheral wall of the hub does not maintain its perfect circle. To explain the welding method in detail, as shown in FIG. 1, a rotating table 1 to which a fixed frame 1A is attached
A spoke plate 4 having a rim 3 welded to the outer end in the radial direction is fitted onto the hub 2 placed on the hub 2.
A single welding torch 5 is fixed at a predetermined position from diagonally above the fitting part between the outer wall and the inner end of the spoke plate 4, and in this state, the welding torch 5 is energized, and the rotary table I was doing 1 by rotating it once. When using the conventional welding method as described above, due to welding distortion due to heat, heating time required for welding, etc.
If the inner circumferential wall of the hub does not maintain a perfect circle, and the amount of deflection (indicated by diagonal lines) is exaggerated and the inner circumferential wall of the hub is drawn, Figure 2a is obtained.
It's like this. Therefore, in order to keep the error on the inner circumferential wall of the hub, which directly affects braking, within the allowable range, it is necessary to correct the distortion using a lathe after welding.
Production efficiency was poor and production costs were high. As a result of our investigation, we found that in order to shorten the heating time required for welding, multiple welding torches are divided into equal parts along the circumferential direction, and in this state, each welding torch is energized, and the number of welding torches is A method of welding by rotating a rotary table was also proposed. Experimentally, welding was carried out by using two welding torches arranged at equal intervals of 180 degrees in the circumferential direction, and by energizing both torches and rotating the rotary table by 180 degrees. If the inner circumferential wall of the hub was exaggerated (shown with diagonal lines), it would look like the one shown in FIG. However, as is clear from a comparison of Figure 2a with a single welding torch and Figure 2b with two welding torches, there is a kind of directionality in the locations where strain occurs. The present invention has been made to solve the above-mentioned problems, and it also includes a cooling device that absorbs the heat generated during welding that causes distortion.
Using three or more welding torches equally divided along the circumferential direction, weld the hub and spoke plate together.
The key point is that welding is performed while cooling the hub portion including the vicinity of the welded portion and while maintaining the perfect circle of the inner circumferential wall of the hub. First, a welding apparatus according to the present invention will be described below based on the drawings. The expanded cooling core 11, which absorbs heat that causes distortion and maintains the circularity of the inner circumferential wall of the hub, is a collect type cooling core that forms cuts 12, as shown in FIG. The upper part of 11A is undercut to form an inclined surface 11B, which contracts in the radial direction due to the vertical movement of the collect core 33, which will be described later.
Cooling chamber 1 that expands and opens on the bottom side
3... are provided in an appropriate number, the openings of which are closed by a lid 14 constituted by a supply pipe 14a and a discharge pipe 14b whose tips are located above the cooling chamber 13, so that each cooling chamber 13 is an airtight chamber. It is becoming. Next, to describe the entire welding apparatus according to the present invention in detail, as shown in the longitudinal cross-sectional view of FIG.
It is constructed by a combination of a bevel gear 24 attached to a pulley 23 connected to the drive shaft of the motor 22 via a bevel gear 25 attached to the rotating shaft 1B of the rotary table 1, and a bevel gear 25 attached to the rotating shaft 1B of the rotary table 1.
For example, as shown in the figure, the vertical movement mechanism 30 of the collet core 33, which expands upward to engage with the inclined surface 11B of The shaft 31 is fitted, the lower end of the vertical shaft 31 is fixed to the cylinder rod of a cylinder 32 that moves the vertical shaft 31 up and down, and the upper end is fixed to the collector core 33, and the cooling mechanism section is fixed. Reference numeral 40 is configured by drilling a coolant inlet 41 connected to the supply pipe 14a of the expanded cooling core 11 and a coolant outlet 42 connected to the discharge pipe 14b in the rotary table 1. Note that there is an appropriate space between the bottom surface of the upper wall of the hub 2 and the top surface of the collect core 33. Note that reference numeral 51 in FIG. 4 is a support that is fixed to the rotary table 1 with bolts 51 in order to stably support the expanded cooling core 11. In the welding apparatus described in detail above, three welding torches 5 are arranged at equal intervals of 120 degrees in the circumferential direction as shown in the plan view of FIG. The expanded cooling core 11 is pushed out to maintain the circularity of the inner circumferential wall of the hub 2, and each welding torch 5 is energized while injecting a cooling medium from the cooling medium inlet 41 into the cooling chamber 13. In this state, drive the motor 22,
Welding was performed by rotating rotary table 1 by 120 degrees. In the above embodiment, three or more welding torches arranged at equal intervals in the circumferential direction are fixed, and a rotary table on which spoke plates welded to the hub and rim are fitted and fixed is rotated. Although the welding apparatus is used for welding, it may be a welding apparatus in which a rotary table is fixed and three or more welding torches are simultaneously rotated in the same direction along the circumferential direction to perform welding. Thus, the inner circumferential wall of the hub when welded using such a method is as shown in Fig. 2c if the amount of deflection (indicated by diagonal lines) is exaggerated. When two welding torches are used, it is a one-way ellipse, when two welding torches are used, it is a two-way ellipse, and when three welding torches are used, it is a three-way ellipse, and the number of welding torches is increased as much as the equipment allows. By doing so, the circularity of the inner circumferential wall of the hub is maintained. For reference, we tested 10 each for single, two, and three cases (while maintaining the circularity of the inner peripheral wall of the hub and cooling the welded part), and experimentally for three cases without holding or cooling. The data from the experiments are summarized in the first section below.
The results are shown in the table, and the average values are shown in FIG.

[Table] Note that the runout amount in Table 1 indicates the maximum error amount of the runout from the perfect circle inscribed in the inner circumferential wall of the hub after welding. Note that the amount of runout in Table 1 indicates the maximum amount of error that deviates from a perfect circle inscribed in the inner circumferential wall of the hub after welding. As detailed above, in the present invention, the distortion due to the heat generated during welding can be reduced by using three or more welding torches equally divided along the circumferential direction to By welding while cooling and maintaining the perfect circle of the inner circumferential wall of the hub, the
It is clear from Fig. 6 that the strain is uniform, and the amount of deflection of the inner peripheral wall of the hub compared with the conventional method using a single welding torch can be much reduced and suppressed within the allowable range. There is no need for distortion correction, and the welding time per wheel is shortened, which improves production efficiency and reduces production costs.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the conventional welding method, and Fig. 2 a, b, and c show the deflection of the inner peripheral wall of the hub after welding with a single welding torch, two welding torches, and three welding torches. 3 is a perspective view showing an expanded type cooling core according to the present invention, FIG. 4 is a vertical sectional view showing the entire welding device according to the present invention, and FIG. 5 is a diagram showing three welding devices. FIG. 6 is a plan view of the welding equipment arranged in equal 120° divisions along the circumferential direction, and FIG. 6 is a graph showing the quantitative relationship of the average values shown in Table 1. 1... Rotating table, 1A... Fixed frame, 1B...
...Hollow rotating shaft, 2...Hub, 3...Rim, 4...
Spoke plate, 5... Welding torch, 11... Expanded cooling core, 11A... Inner peripheral wall, 11B... Inclined surface, 12... Cut, 13... Cooling chamber, 31...
...Vertical axis, 22...Motor, 32...Cylinder, 33...Collection core, 41...Cooling medium inlet, 42...Cooling medium outlet.

Claims (1)

[Scope of Claims] 1 The welded portion between the hub and the spoke plate is cooled by using three or more welding torches equally divided along the circumferential direction, while cooling the hub portion including the vicinity of the welded portion.
A welding method for fixing a hub and a spoke plate in a steel plate wheel for a motorcycle, characterized in that the welding is carried out while maintaining the perfect circle of the inner circumferential wall of the hub. 2. A collet-type expanded cooling core that has an inclined surface formed on the upper part of the inner circumferential wall, an appropriate number of cooling chambers, and a cutout, and the expanded cooling core that is fixed to a hollow rotating shaft connected to a drive source. A rotary table with a fixed frame and a cooling medium inlet and a coolant outlet connected to the cooling chamber, and a vertical shaft whose lower end is fixed to the cylinder rod of the cylinder slides into the hollow rotating shaft of the rotary table. a collet core metal that is freely penetrated and fixed to the upper end of the vertical shaft and that extends upward to engage with the inclined surface of the expandable cooling core; and a hub that is placed and fixed on the rotary table. A hub and a spoke plate in a steel plate wheel for a motorcycle, characterized in that the hub and the spoke plate in a wheel made of a steel plate for a motorcycle are comprised of three or more welding torches equally divided and arranged along the circumferential direction at the welding part between the hub and the spoke plate welded to the rim. Welding equipment that sticks.