JPS61283467A - Shaft feeding unit for spot welding gun - Google Patents

Abstract

PURPOSE:To form an oil film on a sliding face always and to enable the prevention in advance from a defective electrification by enclosing a conductive grease or oil, etc. inside the closed chamber to contain a contactor. CONSTITUTION:Gun arms 2, 3 are rotated centering around a common axis part at welding time. The feeding axis 3 fixed to the gun arms 2, 3 and feeding bush 7 are relatively rotated in the state of being in contact with each contactor 16, 17 and a pressing force acts on the body to be welded being pinched between electrode chips. On electrification then the welding current is passed to a feeding bar 10 from the output terminal (ta) of a welding transformer T and flowed to the feeding axis 4 via the contactor 17. The current reaches the electrode chip through the gun arm 3 of one part and reaches the feeding bush 7 with its flowing to the electrode chip of the other through the body to be welded. The current passes a feeding bar 9 via the contactor 16 and returns to the output terminal (tb) of the transformer. An oil film is formed on the feeding face of the contactor and the contact feeding is performed in a good contact state.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is a further advantageous version of the shaft power supply unit for a spot welding gun disclosed in Japanese Patent Application No. 58-206392 filed earlier.

(Prior Art) The previously filed invention was designed to provide a removable and replaceable axial power supply unit, and by eliminating the external power supply mechanism of the spot welding gun, the secondary circuit of the welding gun was substantially reduced. The aim is to make the welding gun lighter and more compact and to save power by reducing impedance. Specifically, the two gun arms of the spot welding gun are commonly supported by a support bracket. It has a power supply shaft and a power supply bushing rotatably inserted into the shaft in an insulated state, one gun arm is mounted on the outer circumferential surface of the pivot shaft, and the other gun arm is mounted on the outer circumferential surface of the bushing. A pair of positive and negative power supply bars is installed on each conductor such as the pivot shaft and bushing, and a gun arm is installed between each of the above conductors and each corresponding power supply bar. It is characterized in that it is electrically connected via a pair of positive and negative conductors having appropriate pressing means so that it can respond to the pressurizing movement. In the power supply unit described in L, sintered metal is used as the conductive material of the conductor, and conductive oil is impregnated inside the conductor, and this is absorbed by capillary action due to frictional heat caused by sliding on the power supply surface. The conductive oil oozes out onto the surface of the sliding part and forms an oil film to prevent the power feeding surface from becoming rough.

(Problems to be Solved by the Invention) However, the weak point of the above unit is that the formation of the oil film is caused by the generation of frictional heat in the sliding part of the conductor, and therefore, the formation of the oil film is caused by intermittent shaking during welding. When the movement is repeated, it is difficult to generate frictional heat during the first oscillating movement, so there is a problem that a sufficient oil film is not formed, and sometimes the oil film runs out, causing roughness on the power supply surface and causing electrolytic corrosion. there were.

(Means for solving the problem) Therefore, the present invention has added a new improvement plan to make the previously filed invention even more effective, and the specific means are as follows:
The spot welding gun has a power supply shaft that commonly pivotally supports the two gun arms of the spot welding gun on a support bracket, and a power supply bushing that is rotatably inserted into the shaft in an insulated state, is fixed to one gun arm, and the other gun arm is fixed to the outer peripheral surface of the bushing, respectively.
A pair of positive and negative power supply bars is installed on each conductor such as the pivot shaft and bushing, and a pair of positive and negative power supply bars is installed to correspond to the above-mentioned conductors. In order to be able to respond to movements, they are electrically connected via a pair of positive and negative conductors with appropriate pressing means, and the conductors are housed in a sealed chamber filled with conductive grease, conductive oil, etc. (Function) In the present invention, conductive grease, conductive oil, etc. are sealed in the sealed chamber housing the conductor, so that an oil film is formed on the sliding surface of the member. In addition to being able to prevent electrical failure due to lack of oil film, it is also possible to protect the interior of the space in which the conductor is housed from moisture and pollution, thereby further solidifying the objectives and advantages of the previously filed invention.

(Example) Embodiments of the present invention will be described below based on the drawings.

In FIGS. 1 and 2, the specific structure of the axial power supply unit 1 includes a power supply shaft 4 constituting one rotating conductor that passes through two gun arms 2.3 in common. An insulating material 6 is fitted onto the outer peripheral surface from one side until it is located at the protrusion 5, and a power feed bushing 7 constituting the other rotating conductor is fitted onto this insulating material. and the power supply bushing 7. One end 2a of the bifurcated gun arm 2 is fixed to the outer peripheral surface of the power feeding bush 7 by bolting, and the other end 2b is rotatably attached to the outer peripheral surface of the power feeding pivot 4 via an insulating material 8. installed. The other gun arm 3 is inserted between the forks and directly fixed to the outer peripheral surface of the power supply shaft 4 by tightening bolts.

The tip of the power feed shaft 4 is attached to one side plate 23b of the support bracket 23 attached to the welding transformer T, and the feed bushing 7 is attached to the other side plate 23a with insulating materials 8' and 8, respectively.
'', and between one end 2a of the gun arm and the side plate 23a, cooling water is passed directly to the outer peripheral surface of the power supply bushing 7 to reduce the temperature caused by the heat generated in the secondary conductor. A water cooling adapter 28 having an annular water cooling groove 27 to prevent rising is inserted.

The two gun arms 2.3 rotate relative to each other about the same axis, so that the necessary pressure for welding can be applied between the electrode tips attached to the tips of the gun arms. A pair of power feed bars 9.10 correspond to the ends where the power feed shaft 4 and the power feed bush 7 overlap each other from the intersecting direction, and between these two power feed bars 9.10,
They are fixed in an overlapping state with each other via an insulating material 11. That is, one power supply bar 9 is provided with a shaft hole 12 that faces the end of the power supply bushing 7, and a part of this shaft hole 12 and the outer peripheral surface of the power supply bush 7 are sealed with a sealing material 15'. The other power supply bar 10 is provided with a shaft hole 13 that faces the end of the power supply shaft 4.
Water cooling holes 34.35 are bored around the shaft holes 12 and 13 of each power supply bar 9.10.

A plurality of spring insertion holes 14 are bored around the shaft hole 13 of one power supply bar 10 radially from the center of the shaft hole. In the shaft hole 12 of the power supply bar 9 corresponding to the power supply bush 7, there are a plurality of divided conductors 16 that are pressed against the side surface of the tip of the power supply pushbutton and the inner surface of the shaft hole 12 by a pressing means to be described later. As shown in FIG. 3, they are arranged in a ring shape, and in the shaft hole 13 of the power feed bar 10 corresponding to the power feed shaft 4, a plurality of divided conductors 17... are arranged in the power feed shaft 4. The side surface of the tip of the shaft hole 13 is electrically connected to the inner surface of the shaft hole 13 in a press-contact state.

These conductors 16, 17 are made of sintered metal, the interior of which is impregnated with conductive oil.

The contact surfaces between each conductor 16.17, the power supply shaft 4, and the power supply bush 7 are made into "R surface" or "spherical surface" to prevent movement and lateral vibration when the gun arm 2.3 of the welding gun is pressurized.
The structure may be such that it can be handled with sufficient contact.

As the pressing means, for example, hydraulic pressure or springs 18, 19 are used as spring members. One of the springs 18 is inserted through each spring insertion hole 14 of the power supply bar 10, and a wedge-shaped pressure ring 20 provided inside the shaft hole 12 of the power supply bar 9 receives the spring force, and the conductor 1
The conductor 16 is engaged with and pressed by the tapered surface of the power supply bushing 7, and the conductor 16 is pressed against the side surface of the tip end of the power supply bushing 7 and the inner surface of the shaft hole 12 by its wedge action.

Further, the other spring 19 is connected to the shaft hole 1 of the power supply bar 10.
2 and presses the conductor 17 via the wedge-shaped pressure ring 21 against the side surface of the tip of the power supply shaft 4 that has entered the shaft hole 12 of the power supply bar IO and the inner surface of the shaft hole 12. These springs 18 and 19 are respectively housed in a compressed state in two chambers 32 and 33 formed by providing a partition wall 31 inside the casing 25. This casing 25 is attached to the side plate 2 of the support bracket 23 by inserting a common bolt 22.22 into the pair of power supply bars 9.10.
The tightening is fixed at 3a. Therefore, the shaft power supply unit 1 can be easily replaced by simply attaching and detaching the bolts 22, 22 and 29, 30 of each arm 2.3.

The two chambers 32, 33 of the casing 26 are connected to the power supply bar 9.
The shaft holes 12, 13 and the spring insertion hole 14 of No. 10 are communicated with each other to form a sealed chamber. Then, conductive grease or conductive oil is supplied into this sealed space from the supply port 26 of the casing.

Thus, during welding, when the gun arm 2.3 is rotated about the common pivot by the pressurized cylinder, the power feed shaft 4 and the power feed bushing 7 fixed to the gun arm 2.3, respectively, are rotated by the power feed shaft 4 to which the gun arm 2.3 is fixed. and power supply axis 7
The conductors 16 and 17 rotate relative to each other around the same axis x-x while in contact with each conductor 16 and 17, and apply the necessary welding force to the welded object (not shown) which is squeezed between the electrode tips. Pressure acts. Next, when a welding current is applied, the welding current flows through the power supply bar 10 from the output terminal ta of the welding transformer T, and passes through the conductor 17 to the power supply shaft 4. The current flowing through the power supply shaft passes through one gun arm 3 to the electrode tip, passes through the object to be welded to the other electrode tip, passes through the gun arm 9, and reaches the power supply bush 7. The current flowing through the feed bush 7 further passes through the conductor 16, the feed bar 9, and returns to the output terminal tb of the welding transformer. An oil film of conductive oil or the like is always formed on the conductor power supply surface in the pivot portion of the gun arm 2.3 of the welding gun, and contact power supply is performed in a good contact state.

(Effects of the Invention) As described above, according to the shaft power supply unit of the present invention, since conductive grease or conductive oil is sealed in the sealed space into which the conductor is inserted, an oil film is constantly formed on the surface of the power supply member such as the conductor. This can prevent electrical corrosion on the sliding power supply surface. Furthermore, by filling the space with conductive oil or the like, it is possible to protect the sliding power supply surface such as the conductor from the intrusion of water or foreign matter from the outside, or from moisture and contamination inside the space.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of an axial power feeding unit for a spot gun according to the present invention. FIG. 2 is a view taken along the line A-A in FIG. FIG. 3 is a view taken along the line B-B. 1... Axis power feeding unit 2.3... Gun arm 4... Power feeding axis 18.19... Pressing means 7... Power feeding bush 32.33...
・Closed room 9.10...Power supply bar

Claims (1)

[Claims] Two gun arms (2), (
3) on the support bracket (23) in common, and a power feeding bush (7) rotatably inserted into the pivot in an insulated state. 4), and the other gun arm (3) is fixed to the outer circumferential surface of the bushing (7). A pair of positive and negative power supply bars (9), (10) are installed in order to correspond to each other, and the distance between each of the conductors and the corresponding power supply bars (9), (10) is such that the gun arm can be pressurized. suitable pressing means (18) so as to be able to respond to movements;
, (19), a pair of positive and negative conductors (16), (
electrically connected via the conductor (17) and the conductor (16
), (17) are shaft power supply units for spot welding guns that are housed in a sealed chamber filled with conductive grease, conductive oil, or the like.