WITH AN ADJUSTABLE CONNECTING-ROD AND

THE TECHNOLOGY OF MANUFACTURING OF

THE PISTON-CONNECTING ROD UNIT.

The object of this invention is the piston-connecting rod unit with an adjustable connecting-rod, that may be applied especially in hermetic compressors, as well as the technology of its manufacturing.

There is known from the German patent application No. 30 30 319 the connecting-rod of a compressor, especially used in hermetic compressors of coolers, where the piston, fixed on the connecting-rod ball, is joined with the connecting-rod foot through the sectional connecting-rod. The parts of the connecting-rod are joined together by soldering after the piston-connecting rod sub- assembly has been assembled with the compressor shaft crank-pin in the housing-cylinder block being a monolith.

Such a design does not allow for clearance space adjustment in the compressor.

There is also known from the Polish patent description 162 054 the ball-and-socket joint piston, in which the ball is connected with the connecting-rod using welding and bonding technologies, and through the necking of a cylindrical protrusion of an internal part of the piston on the ball, using intermediate flexible insert, the ball and the piston are joined together.

Such a design does not allow to adjust the outer dead centre of the piston in the compressor's cylinder otherwise than through

dislocation of the cylinder in relation to the compressor's housing, which excludes application a housing and a piston as a one block of a compressor. Furthermore, the design mentioned above requires specialised tools for the necking process and cannot 5 guarantee that an accurate clearance in the ball-and-socket joint connecting the piston with the connecting-rod is achieved.

The essence of this invention is the piston-connecting rod unit with an adjustable connecting-rod, in which, inside the cup- o like piston skirt, the sleeve-like holder of the socket of the ball installed on the front of the shaft being the frontal part of the connecting-rod, is centrally fixed. The flexible clamping insert, fixed inside the holder by using a ring washer, supports the ball. The shaft on the opposite side of the ball has a thread, whereto the 5 coupling of the connecting-rod foot is fixed.

The internal diameter of the sleeve-like holder is a little bit larger than the ball's diameter and at least three lubricating holes are placed on its side surface at the height of the ball axis. The piston skirt has, on the cylindrical surface, at least three holes facing the o holes of the holder.

The manufacturing technology of the piston-connecting rod unit is that the piston skirt is brazed to the sleeve-like holder, and then between the piston skirt and the holder, the technological bushing is placed which perfectly fills the space between these two 5 parts approximately up to the half of the holder's height. Then, after the protruding part of the holder has been belled, the bearing socket is placed into the holder and, using a technological ball having diameter equal to the diameter of the ball, a mating surface of the socket and the ball is being formed. The ball joined with the o threaded shaft, the flexible insert and the ring washer are inserted

into the so manufactured sub-assembly, and after taking out the technological bushing from the space between the piston skirt and the holder, the washer inside the holder is clamped. Then, screwing onto the shaft the threaded coupling of the connecting- 5 rod foot, the outer dead centre of the piston skirt front is set in the cylinder and afterwards the piston-connecting rod unit is integrated. The ball is joined with the shaft with a hard solder. To avoid undesired oxidation, the best results are achieved when a blanket furnace brazing using a copper is applied. Then, the ball is

7o galvanised, preferably a nickel electroplating should be used, and the thickness of the ball's coating should compensate decrease of the ball's diameter during the soldering process. The screw joint of the shaft and the sleeve is protected from loosening by means of gluing or screwing on a lock-nut. 5

The advantage of the present invention lies in minimisation of the clearance space in the compressor through adjustment of the outer dead centre of the piston inside the cylinder as well as possibility of applying in the compressor's design the housing- 0 cylinder sub-assembly being a one block.

The object of this invention is shown on the drawing, where Fig. 1 presents the longitudinal section of the piston-connecting rod unit, and Fig. 2 shows the location of the unit in the housing- 5 cylinder sub-assembly of the hermetic compressor.

The piston-connecting rod unit with an adjustable connecting-rod in which, inside the cup-like piston 1 skirt there is installed centrally the sleeve-like holder 2 of the socket ^ of the o ball 4 being inseparatably fixed to the front of the shaft 5 being the

frontal part of the connecting-rod. The ball is supported by the flexible clamping insert 6, fixed inside the holder 2 by using a ring washer 2, arid the shaft 5 on the opposite side of the ball 4 has a thread, whereto the coupling 8 of the foot of the connecting-rod <) is fixed. The internal diameter of the sleeve-like holder 2 is a little bit larger than the diameter of the ball 4 and has at least three lubricating holes 10 placed on its side surface at the height of the ball 4 axis. The piston 1 skirt has on the cylindrical surface at least three holes ϋ, facing the holes 10 of the holder 2. The manufacturing technology of the piston-connecting rod unit is that the cup-like piston 1 skirt is brazed to the sleeve-like holder 2, and then between the piston 1 skirt and the holder 2, the technological bushing is placed which perfectly fills the space between these two parts approximately up to the half of the height of the holder 2. Then, after the protruding part of the holder 2 has been belled, the bearing socket $ is placed into the holder 2 and, using a technological ball having diameter equal to the diameter of the ball 4, a mating surface of the socket i and the ball 4 is being formed. The ball 4 joined with the threaded shaft 5* ^me flexible insert 6 and the ring washer 2 are inserted into the so manufactured sub-assembly, and after taking out the technological bushing from the space between the piston 1 skirt and the holder 2, the washer 2 inside the holder 2 is clamped. Afterwards, through screwing the shaft 5 into the threaded coupling 8 of the connecting-rod 9 foot, the outer dead centre of the piston 1 skirt front is set in the cylinder 12 and next the piston-connecting rod unit is integrated. The ball 4 is joined with the shaft 5 with a hard solder, preferably, to avoid oxidation, a blanket furnace brazing using a copper should be applied, and then, the ball 4 is

120 electroplated, preferably with a nickel coating of the thickness compensating decrease of diameter of the ball 4 during the soldering process. The screw joint of the shaft > and the sleeve 8 is protected from loosening by means of gluing or screwing on a lock-nut 23 _. -

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