Device acting as a bearing and as a support and upper guide for a drive shaft in a motor-compressor unit

Abstract

 A device (8) acting as an upper bearing and as a support and guide for a drive shaft (3) in a motor-compressor unit (1), said shaft (3) being driven by an electric motor of known type associated with a compressor casing (2), in a seat (5) of which said shaft (3) rotates, said device (8) comprising a pressed body (10) with at least two opposing faces (15, 16) and provided with a through hole (11) to receive the upper part (7) of the drive shaft (3), said body (10) comprising discrete regions (20, 21, 22) in which it is fixed to the compressor casing (2), said discrete fixing regions (20, 21, 22) at least partly limiting the mechanical forces generated in the device (8) during the rotation of the drive shaft.

Description

[0001] This invention relates to a device acting as an upper bearing and as a support and guide for the drive shaft of a motor-compressor unit, said shaft being driven by a known electric motor associated with a compressor casing, in a seat of which said shaft rotates.

[0002] As is well known a bearing device (or simply bearing) of known type comprises a generally annular body arranged about the drive shaft, with substantially its entire surface resting on the compressor casing. This bearing is generally constructed by casting, and after casting is subjected to mechanical machining for finishing purposes (removal of burrs, surface operations and the like).

[0003] Such a bearing is therefore of high construction cost deriving both from the casting and from the subsequent finishing. In addition, if not done perfectly, the casting process can produce cracks within the body of the bearing which can trigger embrittlement of the bearing, with the possibility of breakage during the use of the compressor, and its possible subsequent jamming.

[0004] In particular, if the compressor is used in a usual refrigeration circuit of a refrigerator or freezer, the jamming of the compressor results in stoppage of the refrigeration circuit, with obvious preservation problems for the food located in the refrigerator or freezer in which the circuit is used.

[0005] An object of the present invention is to provide a device acting as a bearing (or simply a bearing) which can be produced at low cost and is of reliable use.

[0006] A further object is to provide a bearing of the stated type which is simple to mount in the compressor.

[0007] A further object is to provide a bearing of the stated type which is able to withstand forces arising from an alternating load without any mechanical problem, and can hence withstand vibration and friction acting on it during the use of the compressor and the known movement of the drive shaft, without jamming.

[0008] These and further objects which will be apparent to the expert of the art are attained by a device acting as a bearing and as a support and upper guide for a drive shaft in a motor-compressor unit of the aforesaid type, characterised by comprising a pressed body with at least two opposing faces and provided with a through hole to receive the drive shaft, said body comprising discrete regions in which it is fixed to the compressor casing, said regions being arranged relative to each other in such a manner as to at least partly limit the mechanical forces generated in the device during the rotation of the drive shaft.

[0009] The present invention will be more apparent from the accompanying drawing, which is provided by way of non-limiting example and in which:

Figure 1 is an exploded partial view, with certain parts omitted for greater clarity, showing a compressor provided with the device according to the invention;

Figure 2 is a section through the device of the invention on the line 3-3 of Figure 3; and

Figure 3 is a view of the device of Figure 2 from below.

[0010] With reference to said figures, a motor-compressor unit 1 is partly represented in terms of only some of its components, and comprises a compressor casing 2 with which a usual electric motor (not shown) is associated in known manner to rotate a drive shaft 3 rotatably housed in a corresponding seat 5 in the compressor casing 2. The shaft 3 is of known type and is associated lowerly with a usual oil dip vessel 6 and upperly with a usual connecting rod-piston unit (not shown). The top 7 of the shaft 3 is arranged to cooperate with the device 8 of the present invention, which acts as a bearing, a support and an upper guide for the rotation of the shaft.

[0011] Said device comprises a pressed plate body 10 with a through hole 11 arranged to receive the top 7 of said shaft. This hole opens at 12 and 13 into two flat faces 15 and 16 of the plate body 10.

[0012] The hole 11 is formed preferably by deep-drawing such that on the face 15 of the body 10 its exit 12 is bounded perimetrally by an annular raised portion 17.

[0013] The pressed plate body 10 also comprises discrete fixing regions 20, 21, 22 arranged to cooperate with corresponding portions 23, 24, 25 of the compressor casing 2 and to be fixed to these latter.

[0014] Specifically, each fixing region is provided with a through hole 26 to receive a corresponding screw 27 (or equivalent fixing element). This screw cooperates with a corresponding threaded seat 29 provided in the relative portion 23, 24, 25 of the compressor casing 2. Preferably and advantageously, the holes 26 and hence the screws 27 are positioned at the vertices of an ideal triangle the surface of which is largely defined by the plate body 10. During the use of the compressor with movement of the drive shaft 3, this arrangement limits the mechanical forces deriving from the rotation of the shaft within the hole 11 and acting on the body 10. In this respect, the particular arrangement of the screws 27 (and hence of the points at which the body 10 is fixed to the compressor casing 2) prevents the creation of a couple tending to bend the body 10. Consequently it prevents mechanical deformation of this latter and any possible vibration deriving from this.

[0015] The device 8 is of simple construction and of very low constructional cost compared with analogous known types.

[0016] The device 8 is also of reliable use and provides high reliability in the guiding and support of the drive shaft.

[0017] A particular embodiment of the invention has been described. Other embodiments are however possible (for example one in which there are more than three fixing points), which however are to be considered as falling within the scope of the present document.

Claims

1. A device acting as an upper bearing and as a support and guide for a drive shaft in a motor-compressor unit, said shaft being driven by an electric motor of known type associated with a compressor casing, in a seat of which said shaft rotates, characterised by comprising a pressed body (10) with at least two opposing faces (15, 16) and provided with a through hole (11) to receive the drive shaft (3), said body (10) comprising discrete regions (20, 21, 22) in which it is fixed to the compressor casing (2), said regions (20, 21, 22) being arranged relative to each other in such a manner as to at least partly limit the mechanical forces generated in the device (8) during the rotation of the drive shaft (3).

2. A device as claimed in claim 1, characterised in that the body (10) is of pressed plate and is deep-drawn at the through hole (11).

3. A device as claimed in claim 2, characterised in that a raised edge (17) is formed on at least one of the opposing faces (15, 16) of the pressed plate body (10) in correspondence with an exit (12) of the through hole (11).

4. A device as claimed in claim 1, characterised in that each fixing region (20, 21, 22) is provided with a through hole (26) to receive a respective screw (27) or similar fixing element, which cooperates with a threaded hole (29) provided in the compressor casing (2).

5. A device as claimed in claim 1 or 4, characterised in that the fixing regions are arranged at the vertices of an ideal triangle.

Drawing