Rotary machine

Abstract: A rotary machine having a machine body, and a cover covering an open end of the machine body. The cover is mounted and fixed to the machine body by an improved structure. Cover mounting hooks formed as elastic plate-shaped members are provided on the peripheral edge of the cover which is adjacent to the open end, and the distal end portion of each hook projects from the peripheral edge and has a folded end. Mounting portions are provided at the open end of the machien body, and allow the hookds to be inserted therein. Therefore, the cover can be assembled onto the machine body with ease, at improved efficiency, and at low cost.

Description: BACKGROUND OF THE INVENTION The present invention relates to a construction of a rotary machine such as a totally enclosed fan-cooled rotary motor as defined in the preamble of claim 1. A conventional totally enclosed fan-cooled rotary motor has, as shown in Fig. 5, a fan cover 1 for covering a cooling fan (not shown) of the machine. The fan cover 1 is fixed by bolts 8 to fan cover mounting seats 7 which are in turn formed on an end bracket 6 provided at one end of a cylindrical stator frame 3. The conventional motor of the above-mentioned type entails the following problems. During manufacture, since the process of assembling the fan cover inevitably involves the steps of positioning the fan cover and fastening the bolts, it is difficult to improve the efficiency of the assembly operation. In addition, since the assembly requires a large number of component parts, it is difficult to reduce production cost. A rotary machine in which a peripheral edge of an end cover is fixed to an open end of a machine body using mounting hooks is known from DE-A-3 532 713. In this prior machine mounting portions are formed as bayonet type fittings on the outer circumference of a frame part of the machine body and the mounting hooks formed at inner circumference of the peripheral edge of the cover are engaged in the mounting portions. This prior art solution is disadvantageous in the respect that it requires the particular shape of the mounting portions and a twisting motion of the cover upon mounting thereof at the machine body. SUMMARY OF THE INVENTION An object of the present invention is to provide a means for mounting a fan cover of a rotary machine to the machine body that enables a reduction in the production cost, while facilitating the cover assembly operation and improving the assembly efficiency. To this end, according to the present invention, there is provided a rotary machine comprising the features of the claim 1. A preferred embodiment is defined is a subclaim. With the above-specified construction of the rotary machine, the cover can be fixed to the machine body simply by inserting the cover mounting hooks into the mounting portions from the open end of the machine body. Therefore, the cover can be easily mounted, irrespective of the attitude of the machine body. The distal end portions of the hooks have the folded ends. During the insertion of the hooks into the mounting portions, the folded ends are bent; after insertion, the folded ends exhibit resilience to press against the wall surfaces of the mounting portion, thereby serving to prevent any disengagement of the cover. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a partially-sectioned fragmentary view of a totally enclosed fan-cooled rotary motor according to one embodiment of the present invention; Fig. 2 is an enlarged view of the part indicated by II in Fig. 1; Fig. 3 is a sectional view of a stator frame of the motor; Fig. 4 is an enlarged view of the part indicated by IV in Fig. 3; and Fig. 5 is an enlarged view of essential parts of a conventional rotary machine, showing a conventional cover mounting means. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will now be described with reference to the drawings. Fig. 1 shows the overall construction of a totally enclosed fan-cooled rotary motor according to the embodiment. The machine has a fan cover 1 covering one open end of a stator frame 3 incorporated in the machine body. A flange 4 is provided at the other end of the frame 3, and a shaft 5 projects through the flange 4. A plurality of fan cover mounting hooks 2 are provided on the peripheral edge of the cover 1 which is adjacent to the open end of the stator frame 3, and the distal end portions of the hooks 2 project from the peripheral edge. A plurality of mounting portions 31 open at the open end of the stator frame 3. The fan cover 1 is fixed to the machine body by inserting the plurality of hooks 2 into the plurality of the mounting portions 31. Referring to Fig. 2, each of the fan cover mounting hooks 2 is formed as an elastic plate-shaped member, and it has a folded portion 2a at the distal end. When the hook 2 is being inserted into the mounting portion 31 at the open end of the frame 3, the folded portion 2a is bent. After insertion, by virtue of the resilience of each folded portion 2a, it presses against the wall surface of the mounting portion 31, thereby serving to prevent any disengagement of the cover 1. With the above-described construction, the fan cover 1 can be fixed to the machine body simply by inserting the fan cover mounting hooks 2 into the mounting portions 31 from the open end of the stator frame 3. Thus, a simple structure enables the fan cover 1 to be mounted easily and irrespective of the attitude of the stator frame 3. Therefore, the means for mounting the fan cover enables the machine to be manufactured at low cost and enables the cover assembly operation to be performed at high efficiency. The preferred structure of the cover mounting means will be described in detail with reference to Figs. 3 and 4. In the illustrated embodiment, the mounting portions 31 formed on the stator frame 3 are provided by utilizing grooves adapted to engage with a lifting lug (not shown) for holding the machine body in place. Specifically, the stator frame 3 has a multiplicity of cooling fins formed on the outer periphery of the stator frame 3, and they extend axially. A plurality of fin pairs are each formed by two adjacent fins 3a which face each other. Axial recesses 3b are formed on the mutually facing surfaces of the fins 3a so that the recessed surfaces of the paired fins 3a define a plurality of axial grooves. These grooves serve as lifting lug mounting grooves which engage with a lifting lug (The details of the lifting lug mounting grooves are shown in Japanese Utility Model Application No. 63-141954/JP-U-2-65058. These inter-fin grooves are also used as the cover mounting grooves 31. With the above-described structure of the cover mounting means, the fan cover 1 can be fixed in place by inserting the fan cover mounting hooks 2 into the lifting lug mounting grooves, without requiring the mounting portions 31 to be separately provided. Therefore, the provision of the mounting portions 31 does not require the addition of any special component parts, thereby allowing the total number of component parts to remain small. Accordingly, the means can be produced at low cost, without incurring much increase in the production cost. In the above described embodiment, although the lifting lug mounting grooves are used as the mounting portions of the cover mounting means, this is a mere example. Alternatively, the structure of the means may be such that it utilizes, as the mounting portions, grooves for mounting a housing cover covering the entire machine. Still alternatively, cover mounting portions such as grooves or holes may, of course, be provided separately. If the mounting hooks are formed by using a vibration-damping steel plate material, this makes it possible to restrain vibration from being transmitted from the machine body to the fan cover, thereby providing a noise-preventing effect. Although the description given above concerns the mounting of a fan cover of a totally enclosed fan-cooled rotary motor, this is a mere example. The application of the present invention is not limited to the above-described mounting operation, and the present invention is applicable to the mounting of a cover of a rotary machine in general. For instance, the present invention may advantageously be applied as a method of mounting a fan cover of a reduction gear system, or a method of mounting an air deflector of an open, drip-proof rotary motor. The present invention having the above-described construction provides the following advantageous effects. A cover of a rotary machine is fixed to the machine body simply by inserting cover mounting hooks into mounting portions of the machine body from the pertinent end portion of the body. Therefore, the cover can be mounted easily, irrespective of the attitude of the machine body. Thus, a simple structure which can be produced at low cost facilitates assembly operation. Accordingly, it is possible for a rotary machine to be provided with the highly efficient fan cover mounting means and be manufactured at reduced production cost.

Claims: A rotary machine comprising: a machine body (3) having an open end; a cover (1) covering said open end; and a means for mounting and fixing said cover (1) to said machine body (3), said means comprising: a peripheral edge of said cover (1) which is adjacent to said open end and is fixed to the open end of the body (3) using mounting hooks (2), and mounting portions (31) provided at the open end of the machine body (3), said mounting portions (31) allowing said hooks (2) to be inserted therein, characterized in that said cover mounting hooks (2) are formed as elastic plate-shaped members on said peripheral edge of said cover (1), the distal end portion of each of said hooks (2) projecting from said peripheral edge and having an end folded back toward the cover (1); and said mounting portions (31) allow said hooks (2) to be inserted therein with the folded back ends pressing against a wall surface thereof to prevent disengagement of the cover (1). A rotary machine according to claim 1, wherein said mounting portions (31) of said machine body (3) comprise grooves adapted to engage with a lifting lug for holding said machine body (3) in place.

Inventors: IIDA HIROFUMI, ISHIMOTO NORIYUKI, IIDA, HIROFUMI, ISHIMOTO, NORIYUKI
Applicants: SUMITOMO HEAVY INDUSTRIES, SUMITOMO HEAVY INDUSTRIES, LTD
Application year: 1990
Main classification: H02K9
IPC codes: H02K5, H02K9