GB2094900A

GB2094900A - Motor compressor unit

Info

Publication number: GB2094900A
Application number: GB8204002A
Authority: GB
Original assignee: Necchi SpA
Current assignee: Necchi SpA
Priority date: 1981-02-16
Filing date: 1982-02-11
Publication date: 1982-09-22
Also published as: AR227347A1; GB2094900B; BR8200807A; ES8301353A1; ES509606A0; DE3204594A1; IN156539B

Abstract

A motor-compressor unit for a refrigerator comprises a support body (18) resiliently supported on the base of a hermetically sealed casing (10) of the unit. The body (18), in which a compression cylinder and a silencer chamber (34) in the delivery duct are provided, has a limited radial extension in that portion thereof which is diametrically symmetrical to the silencer chamber. The body (10) supports a stator (12) by means of two columns (42, 44) provided on the body in diametrically opposite positions in proximity to its outer periphery. <IMAGE>

Description

SPECIFICATION Motor compressor unit The present invention relates to a motorcompressor unit for a refrigerator, and has particular reference to a unit in which a crankshaft driven by an electric motor transmits reciprocating motion to a piston sliding in a cylinder provided in a motor support body of the unit.

Such a body is conventionally produced by casting and comprises a cylinder, silencer chambers and a support for a bush for the crankshaft. There is a need, through appropriate configuration of the support body, to reduce the costs and dimensions of the motor compressor unit while keeping its performance unchanged.

According to the present invention there is provided a motor compressor unit comprising a hermetically sealed casing, a support body resiliently supported in the casing and defining a refrigerant gas compression cylinder and a single silencer chamber, the silencer chamber being provided in the gas delivery side of the unit, a stator mounted on the support body by way of two support columns provided on the body in peripheral regions thereof which are diametrically opposite with respect to the stator axis, a rotor rotatably arranged in the stator and comprising a crankshaft, a piston slidably engaged in the cylinder and drivably coupled to the crankshaft, and a gas inlet pipe communicating with a suction chamber in a head of the cylinder and adapted to act as a silencer in the gas inlet side of the unit.

In a preferred embodiment, the support body comprises only one silencer chamber, namely the delivery silencer chamber, and has a limited radial extension in that portion which is symmetrical to the silencer chamber. The inlet pipe for the refrigerant gas is in direct communication with the suction chamber provided in the cylinder head and is so configured as to perform the function of the silencer in the suction duct. The body comprises two column supports for its connection to the stator, the columns being located in diametrically opposite positions about the centre of rotation of said rotor in proximity to the outer periphery of the body.

An embodiment of the present invention will now be more particularly described by way of example and with reference to the accompanying drawings, in which: Fig. 1 is a section through a motor-compressor unit according to the said embodiment, Fig. 2 is a general side view of the unit of Fig. 1, Fig. 3 is a perspective view of a support body of the unit of Fig. 1, and Fig. 4 is a plan view of the support body.

Referring now to the drawings, there is shown a motor compressor unit comprising a hermetically sealed casing 10 enclosing a compressor 12. A stator 14 of an electric motor is disposed in the upper portion of the casing 10 and is provided with stator windings 1 6.

Arranged within the stator 1 4 is a rotor 8 pressfitted on a crankshaft 6 which operates, by means of a connecting rod 4, a piston 2 which slides in the cylinder 22. The stator 14 is supported by a support body 18 of the compressor, the body being shown in detail in Figs. 3 and 4. The body is supported by suitable helical springs 24, only one of which is shown in Fig. 1.

The springs 24 are mounted at their upper end portions on pins 20 provided on the bottom of the body 1 8, and at their lower end portions on columns 26 fixed to the base of the casing 1 0.

With reference to Figs. 3 and 4, the body 18, which is produced by casting, has a central circular bore 27 in which a bush 28 of the crankshaft 6 is disposed. The bush is fixed to the body 1 8 by three screws 30 (only one of which is visible in Fig. 1) disposed in bores 32 in a flange 29 of the body 18.

The body 18 is shaped to define the cylinder 22 and, on its bottom, the support pins 20 for the upper end portions of the springs 24.

With reference to Fig. 3, at one side of the central bore 27 the body defines a silencer chamber 34, which is connected into the gas delivery circuit of the motor-compressor unit and is disposed immediately adjacent to the flange 29 provided on the body 18 for fixing the bush 28. In this manner, the radial extension of the body is kept to the minimum necessary. On the side diametrically opposite to the silencer chamber 34, the radial extension of the body is reduced to a minimum by dispensing with the silencer chamber in the suction duct, such a suction duct silencer chamber being provided in known compressors in a position symmetrical to the silencer chamber in the delivery duct.

The function of the omitted chamber is performed by a tube 38 disposed on the head 40 of the cylinder 22. The tube 38 is dimensioned and shaped in such a manner as to act as a silencer. For this purpose, it comprises frustoconical end portions and an intermediate portion of greater diameter connected to the end portions.

Two column supports 42 and 44 are provided in their upper end portions with two bores 43 and 45, into which are screwed two bolts 48 and 50 which pass through laminations of the stator 14.

The purpose of these bolts is to join the laminations together and to fix the stator 14 to the body 18.

The support surfaces of the column supports 42 and 44 and the fixing bolts are dimensioned in such a manner as to ensure stability of the statorrotor coupling and to obviate any dangerous variations in the air gap between the rotor 8 and stator 1 4.

These objectives are ensured by the fact that with the described arrangement of the column supports 42 and 44, the electro-mechanical forces developed by the motor are absorbed by virtue of a rational and simple form of restraint.

As can be seen in the drawings, because of the basic configuration of the body 1 8 and the rational arrangement of the components, such as the suction tube 38 which also functions as a silencer, the size of the motor-compressor unit, in particular its transverse dimension, is substantially reduced.

As can be seen in Fig. 2, the space normally reserved for the silencer chamber in the suction duct is utilised for housing electrical connections 36 disposed inside the casing 10. The use of only two support columns for the motor also constitutes a simplification of the motor-compressor unit and a reduction in production costs and overall size.

Claims

1. A motor compressor unit comprising a hermetically sealed casing, a support body resiliently supported in the casing and defining a refrigerant gas compression cylinder and a single silencer chamber, the silencer chamber being provided in the gas delivery side of the unit, a stator mounted on the support body by way of two support columns provided on the body in peripheral regions thereof which are diametrically opposite with respect to the stator axis, a rotor rotatably arranged in the stator and comprising a crankshaft, a piston slidably engaged in the cylinder and drivably coupled to the crankshaft, and a gas inlet pipe communicating with a suction chamber in a head of the cylinder and adapted to act as a silencer in the gas inlet side of the unit.

2. A motor compressor unit as claimed in claim 1, wherein the support body comprises a mounting flange for a bush journalling the crankshaft, the silencer chamber being disposed immediately adjacent to the flange.

3. A motor compressor unit as claimed in either claim 1 or claim 2, the support body being constructed substantially as hereinbefore described and as shown in the accompanying drawings.

4. A motor compressor unit substantially as hereinbefore described with reference to the accompanying drawings.

5. A refrigerator comprising a motor compressor unit as claimed in any one of the preceding claims.