GB2042280A

GB2042280A - Casing structure for enclosing and assembling therein a machine, such as an electric motor, of elongated design

Info

Publication number: GB2042280A
Application number: GB8001129A
Authority: GB
Original assignee: Lowara SRL
Current assignee: Lowara SRL
Priority date: 1979-01-12
Filing date: 1980-01-14
Publication date: 1980-09-17
Also published as: BR6000040U; IT7930613V0; JPS5597157A; DE3000003A1

Abstract

A casing for elongated electric motors comprises two like semicylindrical half-shells (7,8) having recessed end zones (9,10) forming abutment shoulders (11,12) one whereof engages against a mating end shoulder (20) provided on head formations (5,6) of the motor. A ring (17) is pressure fitted over the recessed zones to secure the various motor parts together. <IMAGE>

Description

SPECIFICATION Casing structure for enclosing and assembling therein a machine, such as an electric motor, of elongated design This invention relates to a casing structure for enclosing and assembling therein a machine, such as an electric motor, of elongated design.

Elongated or oblong design machines, and specifically electric motors of small diameter and great length, or multistage pumps, are usually obtained by constraining the various components within a casing or housing which may have any of several configu rations.

Usually, such a housing or casing comprises an intermediate element and two heads: in the instance of an electric motor, such as will be discussed by way of example in the ensueing detailed description of the invention, the intermediate element is rigid with the stator laminations and the two heads, accommodating the bearings for the rotor shaft, are either secured to the intermediate element through studs or captive fasteners, or directly to each other by means of through-bolts extending lengthwise thereto.

In both cases, and not to mention those machines where the connection is accomplished by pressure fitting to the casing, various machining steps are required in order to produce exactly mating parts, to arrange for the installation of studs or the forming of tie-bolt passages, and during assembling, a number of operations must be completed to convert the composite structure into a rigid unit.

These same problems are encountered in performing servicing operations which involve disassembling of the machine.

This invention sets out to provide an enclosing and assembling casing structure which overcomes the above shortcomings affecting similar machines of conventional design.

Within that general aim, it is possible to arrange that the casing structure according to the invention affords easy assembling of the various parts which make up the machine, and in particular the components of an electric motor.

It is further possible to arrange that the casing structure according to the invention is composed of few simple parts which, when put together, provide high mechanical strength characteristics.

According to one aspect of this invention, these and other objects can be achieved by a casing structu re for enclosing and assembling therein a machine, such as an electric motor, of elongated design, in combination with the structure of such machines having head formations at opposite ends thereof, characterized in that the casing comprises two half-shells of semi-cylindrical shape and substantially coaxial and coextensive with the machine to be enclosed therein, said two half-shells having at least on one of their ends a radially recessed zone of reduced diameter forming at least one inwardly protruding annular abutment shoulder extending transverse to the longitudinal direction of the machine, and in that at least one of said head formations has at least one mating annular abutment shoulder arranged to engage said inwardly protruding annular shoulder, the casing having at least one ring arranged to be pressure fitted over one of said recessed zones to secure the casing on the machine.

Further features and advantages of the invention will be more clearly understood from the following detailed description of a structure according to the invention, as relating to an electric motor of great length relative to the diameter thereof, and illustrated by way of example but not of limitation in the accompanying drawings, where: Figure lisa general sectional view of an electric motor as enclosed in a casing according to this invention; Figure 2 is an exploded perspective representation of the instant structure; and Figure 3 is a sectional view of one of the two heads.

With reference to the cited drawing figures, the motor which will be described hereinafter is of a type having a great length and comparatively small diameter, which is suitable for coupling to a multistage centrifugal pump, although that same structure can also find application in machines of a different description but having similar geometrical features.

The motor illustrated comprises a stator stamping stack 1, the hollows whereof accommodate stator windings 2 distributed therein, and a rotor 3 which is associated with the motor shaft 4, this latter being supported and guided in two heads 5 and 6.

All these parts are contained within two semicylindrical half-shells,7 and 8, having substantially the same length as the machine overall length and two recessed zones 9 and 10 which form inwardly protruding two semiannular abutment shoulders 11 and 12 extending perpendicular to the machine axis.

As can be more clearly seen in Figure 3, the abutment shoulder 11 engages against an annular mating shoulder 20 formed in the head 5 of the motor, the entire recessed portion 9 fitting into a seat 13, also formed in the head 5.

The distance between the shoulders 11 and 12 is so selected, that the engagement between these two half-shells 7 and 8 and the heads 5 and 6, causes the latter to be pressed axially against the stator pack or stamping stack 1, to also provide water-tightfea- tures through the interposition of suitable sealing means, such as the O-ring 14 (Figure 3), between the head 5 and stator pack 1, and the seals 15 and 16 between the head 5 and motor shaft 4.

To prevent the two half-shells from coming apart and to lock the casing permanently, two rings are provided, one of which is indicated at 17 and is related to the head 5, it being pressure fitted over the recessed zone 9 such as to hold the two half-shells in place.

For locking said ring 17 securely on the two halfshells, a binding screw 18 is provided which passes through the ring 17 and half-shell 7 to threadably engage the head 5.

With this simple arrangement, all the parts which make up this structure can be secured to the motor parts without requiring any additional fastening device.

It will be apparent that with a casing as described above, all the operations for assembling and disassembling the machine are facilitated, both during the initial assembling stage and for subsequent inspection and maintenance purposes.

At the same time, the component parts are easily manufactured, they being substantially formed form sheet metal.

In practicing the invention, the dimensions and materials used may be any ones to suit individual applicational requirements.

Claims

1. Acasing structure for enclosing and assembling therein a machine, such as an electric motor, of elongated design, in combination with the structure of such machines having head formations at opposite ends thereof, characterized in that the casing comprises two half-shells of semicylindrical shape and substantially coaxial and coextensive with the machine to be enclosed therein, said two half-shells having at least on one of their ends a radially recessed zone of reduced diameter forming at least one inwardly protruding annular abutment shoulder extending transverse to the longitudinal direction of the machine, and in that at least one of said head formations has at least one mating annular abutment shoulder arranged to engage said inwardly protruding annular shoulder, the casing having at least one ring arranged to be pressure fitted over one of said recessed zones to secure the casing on the machine.

2. A casing structure according to Claim 1, characterized in that said half-shells are preferably formed by pressing sheet metal.

3. A casing structure according to Claim 1, characterized in that said half-shells have a selected distance between the opposite inwardly protruding abutment shoulders to axially compress said head formations against the intermediate part of the machine, the structure further comprising at said recessed zones sealing members for making the machine fluid tight.

4. A casing structure according to Claim 1, characterized in that said rings are pressure fitted onto the recessed zones of said half-shells at the machine head formations, thereafter screw means are inserted therethrough effective to lock said rings onto the head formations to prevent separation thereof.

5. A casing structure for enclosing and assembling therein a machine, such as an electric motor, of elongated design, substantially as herein described with reference to the accompanying drawings.

6. Any novel element, or combination of elements, herein described and/or shown in the accompanying drawings, irrespective of whether the present claim is within the scope of, or relates to the same invention as, any of the preceding claims.