Introduced in a system for connecting refrigerant fluid discharge tubes to cylinder caps of hermetic compressors, and corresponding process of performing thereof

Abstract

A connecting device includes a substantially cylindrical or tubular body provided, at one of its ends, with an outer perimeter projection and co-operative with a duct of channel of a cylinder cap. The device is preferably producible with steel aluminum alloy, or another metal alloy with similar structural and thermal properties mainly due to the stresses it may suffer during use. The device is configured to be able to absorb tolerance variations and to have a resilience capable of providing resistance at the time when a connection undergoes mechanical stresses of performance, especially torsion.

Claims

1. A process for connecting a refrigerant fluid discharge tube to a cylinder cap of a hermetic compressor, the process employing at least one connecting device comprising: a tubular body provided, at one of its ends, with a perimetral flap co-operative with the discharge tube; the cylinder cap comprising at least one channel co-operative with the at least one connecting device; and at least one layer of sealing material applied on a connecting device surface co-operative with the cylinder cap, and a connecting device surface co-operative with the discharge tube; wherein an end of the discharge tube co-operating with the at least one connecting device has a conical form; wherein co-operation between the discharge tube and the at least one connecting device is made by interference; wherein a surface of the discharge tube co-operating with the at least one connecting device is formed by rolling; wherein co-operation between the at least one connecting device and the at least one channel of the cylinder cap is made by interference; and wherein the at least one connecting device is produced with at least one of the following materials: steel, aluminum alloy, or metal alloy containing steel or aluminum; the process comprising the following steps: rolling the end of the discharge tube; coupling the discharge tube to the at least one connecting device by interference to form a pre-assembly; positioning the pre-assembly of the discharge tube with the at least one connecting device through the at least one channel of the cylinder cap until the discharge tube reaches a stop existing inside the cylinder cap; applying at least one layer of sealing material on the connecting device surface co-operative with the cylinder cap, and the connecting device surface co-operative with the discharge tube; and applying ultraviolet light to promote curing of the sealing material.

2. The process according to claim 1 wherein the discharge tube forms a male-type coupling element for co-operating with a female-type coupling element of the at least one connecting device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will be described in detail on the basis of the figures listed below, in which:

(2) FIG. 1 shows a schematic view of a system for connecting discharge tube of the present state of the art;

(3) FIG. 2 shows a perspective view of a compression cylinder cap to which a discharge tube was fixed with the aid of the connecting device and process, according to a preferred embodiment of the present invention;

(4) FIG. 3 shows a sectional view of a compression cylinder cap suitably coupled to the discharge tube, allowing a detailed view of the position of the connecting device shown herein and its interaction with the other components of the cooling system, and

(5) FIG. 4 shows a flow chart illustrating the process of performing the connection of the discharge tube to the compression cylinder cap, a subject matter of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(6) The subject matter of the present invention will be more fully described and explained on the basis of the accompanying drawings, which are of a merely exemplary and non-limiting character, since adaptations and modifications may be performed without, thereby, escaping from the claimed scope of protection.

(7) The present invention relates to a connecting device (10) which can be best observed by the cross section of the attached FIG. 3, in which it is performed the connection between a discharge tube (1) (produced in copper-covered steel or the like) and a cylinder cap (2) of a hermetic compressor for cooling system.

(8) According to a preferred embodiment of the present invention, the connecting device (10) comprises a substantially cylindrical or tubular body (11) provided, at one of its ends, with a perimeter flap (12) which acts as an auxiliary element for the assembly of said connecting device (10) in the hole, duct or channel (21) of the cylinder cap (2). Preferably, the device (10) will be produced in steel, aluminum alloy or other metal alloy with similar structural and thermal, properties, mainly due to the stresses it may suffer during use and to be able to absorb the tolerance variations and to have a resilience capable of providing resistance at the time the connection undergoes mechanical stresses of performance—especially torsion.

(9) It should be clarified that one of the main functions of the connecting device (10) is to absorb the dimensional tolerance of both the discharge tube (1) and the cylinder cap (2) since, as is known for a person skilled in the art, the cap (2) is made in injected material while the discharge tube (1) is metallic, so that it has a significantly large dimensional tolerance field.

(10) The connection between the discharge tube (1) and the cylinder cap (2) requires an initial pre-assembly procedure in which the connecting device (10) is coupled, by interference, to the discharge tube (1), and then the assemblage of connecting device (10)+discharge tube (1) is coupled to the cylinder cap (2). However, since the coupling of said components will also be made by interference at the ambient temperature, it is assumed that the dilatation of each piece will occur in a different way, so that it becomes necessary to use some adhesive means to aid in the sealing of the connection—which is also required due to the fact that the constituent material of said components does not present, per se, sealing characteristics.

(11) In order for the connection proposed herein to be well performed and to have an appropriate efficiency, the end of the discharge tube (1), preferably, must present a certain conicity at its free end to prevent that the interference of the discharge tube (1) in the connecting device (10) causes the machining thereof with consequent generation of chips from its inner surface.

(12) It should be noted that the inner surface of the connecting device (10) which will remain in contact with the tube (1) must be plain and rectilinear, just to eliminate the chance of occurrence of undue deformations which could arise due to the fact that the discharge tube (1) is much more robust and resistant than the material of the connecting device (10)—remembering that, preferably, the depth of insertion of the connecting device (10) in the discharge tube (1) should be controlled. In a preferred, but non-limiting, embodiment of the invention, the discharge tube (1) is introduced in the connecting device (10) so as to exceed the extension thereof—in other words, not only until the end of the rolling, it being pointed out that there will also be a straight rolling in order to compensate the geometric variations on the entire surface of the discharge tube (1) with which the connecting device (10) contacts—wherein, as the pieces are interfering with each other, the connecting device (10) will expand on the tube (1), deforming both pieces and causing a rigid and perfect coupling.

(13) It should be noted that in a pre-assembly step of the system, the discharge tube (1) is introduced in the connecting device (10) on the side where the perimetral flap (12) is located, wherein said connecting device (10) is drawn by a safe length so that there is no contact between the connecting device (10) and the cylinder cap (2) when the discharge tube (1) reaches the stop (22) inside the cylinder cap (2). Once the said pre-assembly is concluded, the discharge tube (1) is then suitably positioned in relation to the stop (22) existing inside the cylinder cap (2)—in other words, until both components touch—and only after said positioning the connecting device (10) is forced, with the aid of additional apparatus, to enter in the channel (21) having a substantially conical inner surface in order to promote the assembly by interference. In this regard, it is important to point out that there is relative movement between the connecting device (10) and the discharge tube (1), in addition to the relative movement between the connecting device (10) and the cylinder cap (2), so that after the initial assembly by interference is consolidated, it is possible to apply a material capable of promoting the sealing of the connection.

(14) It is also important to make it clear that the perimetral flap (12) of the connecting device (10) acts as an auxiliary element for the assembly, since it provides the additional apparatus used in that procedure with a support element to which it is applied the pressure necessary to conclude the coupling between the pieces. Further, the depth of insertion of said connecting device (10) relative to the channel (21) will be controlled by the insertion force which should be applied in accordance with the mechanical strength of the cylinder cap (2).

(15) The sealing of the connection will be made by the application of adhesive material on the two interfaces of the assembly, one of them being the assemblage of connecting device (10)+cylinder cap (2), and the other interface being constituted by the assemblage of connecting device (10)+discharge tube (1). Once more, it should be clarified that the sealing material used in the connection disclosed herein may comprise an adhesive which, however, operates with the function of a sealing element, and not as an element for gluing or sealing the pieces; therefore, various materials may be used, provided they meet said need. After the application of the sealing material, the application of UV (ultraviolet) light or the like is carried out to promote the curing thereof and, thus, to conclude the assembly of the connection.

(16) In short, the process of connection of refrigerant fluid discharge tubes (1) to cylinder caps (2) of hermetic compressors, a subject matter of the present invention, comprises, therefore, the following steps:

(17) (200) performing the rolling at the end of the discharge tube (1). Said process, which must necessarily be prior to starting the assembly of the connection, leaves only the end of the discharge tube (1) conical to prevent subsequent formation of chip, while in the remainder of the length the diameter of the tube must be ensured on the entire surface with which the connecting device (10) will be in contact;

(18) (210) pre-assembly step: coupling, by interference, of the discharge tube (1) to the connecting device (10), wherein in the preferred embodiment illustrated in the attached FIG. 3, the tube (1) forms a male-type coupling element for co-operating with a female-type connecting device (10);

(19) (220) positioning of the pre-assembled assemblage of discharge tube (1)+connecting device (10) through the duct or channel (21) of the cylinder cap (2) until the discharge tube (1) reaches the stop (22) existing inside the cylinder cap. Said step must be carried out without interference between the connecting device (10) and the cylinder cap (2) for the time being—to this end, the connecting device (10) is drawn to a safe distance so as not to contact the cylinder cap (2) before the discharge tube (1) reaches the stop (22) of the cylinder cap (2);

(20) (230) coupling the connecting device (10) to the channel (21) of the cylinder cap (2). To this end, the connecting device (10) is pressed by its perimetral flap (12) and with the aid of an additional apparatus, to the channel (21) having a substantially conical surface of the cylinder cap (2) in order to couple the discharge tube (1) and the cylinder cap (2) by interference;

(21) (240) applying at least one layer of adhesive material (not shown) on the two interfaces: connecting device (10)+cylinder cap (2), and connecting device (10)+discharge tube (1);

(22) (250) applying UV (ultraviolet) light, or the like, to promote curing of the adhesive/sealing material.

(23) It should be clarified that the solution disclosed herein may be used for the coupling of discharge tubes (1) in cylinder caps (2), regardless of the angle or direction of the coupling.

(24) Therefore, it is noted that the subject matter of the present invention provides an efficient, practical and economical solution for performing the coupling of discharge tubes (or others of the system) in cylinder caps of hermetic compressors for cooling systems.