GB2102512A

GB2102512A - Rotary bearing system in a drive unit

Info

Publication number: GB2102512A
Application number: GB08213878A
Authority: GB
Inventors: Johann Klement
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-06-30
Filing date: 1982-05-13
Publication date: 1983-02-02
Also published as: FR2508735A1; IT8221949A0; DE3125721A1; IT1152255B

Abstract

Drive means, for example an electric motor for an air circulation blower of a baking oven, comprises a drive unit having an output shaft (1) mounted in ball bearings (7) in a stationary support body (2). Each of the ball bearings (7) is connected to the body (2) by means of at least one resiliently yielding bearing element, for example a mass of resilient filling material (8), in which the bearing may be embedded. In a second embodiment the bearings (7) are resiliently mounted in the support body by means of an annular bow spring. <IMAGE>

Description

SPECIFICATION Rotary bearing system in a drive unit The present invention relates to drive means, for example an electric motor for an air-circulating blower of a baking oven.

In the case of drive means, particularly an aircirculating blower motor for a baking oven, which is exposed to high temperatures, the requirements are for low-noise precision bearing of the drive output member with an exact bearing fit, while the bearing material, which is exposed to strong temperature fluctuations, should be able to freely expand, which favours use of a coarse bearing. For the lastmentioned reason, in practice noise-intensive coarse bearings are generally favoured, with expensive heat insulation being avoided.

There is accordingly a need for drive means with a bearing system in which, on the one hand, costintensive and play-free precision bearing and accuracy of fit can be dispensed with and yet in which, on the other hand, a high freedom from noise is obtained.

According to the present invention there is provided drive means comprising a drive unit having a drive output element mounted by rotary bearing means in a support body, the rotary bearing means comprising at least one bearing coupled to the body by resilient means.

According to the preferred embodiment, the or each rotary bearing, preferably a ball bearing, is embedded in a mass of elastic filling material. A particularly noise-damping material, such as silicone rubber, a mixture of metal powder and synthetic material powder or the like can be employed as the filling material. The embedding of the rotary bearing can be carried out mechanically, for example in an injection moulding process, after previous centering of the output element relative to the support body.

Alternatively, spring elements can be employed as the resilient means.

A bearing system according to either embodiment may allow use of a coarse bearing, which can be intensive to extreme temperature fluctuations, for the bearing of the output element. Neverthless, a high measure of freedom from noise can be achieved through the elastic bearing element or bearing material, which acts in a noise-damping manner. Manufacture is substantially simplified in this manner and the costs may be reduced in that the support body can, for example, be constructed as a rough injection-moulded part without further fine processing.

Embodiments of the present invention will now be more particularly described by way of example and with reference to the accompanying drawings, in which: Figure l is a schematic sectional view of drive means according to a first embodiment of the invention; and Figure 2 is a schematic sectional view of part of drive means according to a second embodiment of the inventilon.

Referring now to the drawings, there is shown in Figure 1 drive means in the form of an internal rotor electric motor, although the drive means could of course be used for an external rotor motor. The drive means comprises an output shaft 1 and a stationary bearing body 2 constructed in the form of a housing.

A rotor winding (not shown) is arranged in the region 3 on the output shaft 1 in the interior of the body 2, while the associated stator winding can be housed in the region 4 of the body 2. Laminated rotor irons are designated by 5. The bearing body 2 is provided with respective openings 6 and 6' at both axial ends. The clear widths of the openings 6 and 6' are greater than the diameter of ball bearings 7 representing the rotary bearings, so that the bearings 7 can be inserted with radial play into the circular and bowl-shaped openings 6 and 6'. In the embodiment according to Figure 1, the hollow space between each bearing 7 and the body 2 is filled with a permanently resilient filling mass 8, for example silicone rubber. For the non-rotatable retention of this filling mass moulded part, bores 9 are machined into the sleeve-shaped body 2 and are filled by the filling mass.The openings 6 and 6' are bounded towards the centre by annular shoulders 10 and 10', respectively, wherein the filling mass is also disposed in the region between the lateral end faces of the bearings 7 and the shoulders 10 and 10', respectivey.

In distinction from the embodiment according to Figure 1, in the embodiment of Figure 2 there is used, instead of a filling mass, a spring element which is braced between each bearing 7 and the body 2 and is in the form of a compression spring 11 mounted on the output shaft 1 or plate springs, and a likewise substantially annular bow spring 12. The bow spring 12 possesses a radial ring web 13, an arched bow web 14, and a substantially radial, annular projection 15, which engages into, for example, an encirciling groove within the opening 6 in the body 2 and whereby the bow spring is located to be secure against rotation. The annular web 13 and the bow web 14 enciose and act on the bearing 7 axially and radiallywith mechanical bias, wherein the bias is produced in axial direction by the compression spring 11, against which the bearing 7 resiliently bears. On the other side, the spring 11 bears against the shoulder 10.

In both embodiments, the bearings 7 can deviate resiliently in the directions of movement designated by A and B in Figure 2, yet remain firmly seated on the output shaft 1.

Through the mounting of the rotary bearing, for example a relatively coarse ball bearing, in an elastically yielding bearing element preferably of noise-damping material in accordance with the described embodiments, it may be possible to avoid the need to impose requirements on the accuracy of fit of the bearing seat in the stationary bearing body.

All bearing tolerances are fully compensated for with the introduction of the elastically yielding bearing element into the bearing seat and a high measure of accuracy in circularity of running is thereby achieved.

Claims

1. Drive means comprising a drive unit having a drive output element mounted by rotary bearing means in a support body, the rotary bearing means comprising at least one bearing coupled to the body by resilient means.

2. Drive means as claimed in claim 1, wherein said one bearing is a ball bearing.

3. Drive means as claimed in either claim 1 or claim 2, wherein the or each bearing is embedded in a mass of resilient material.

4. Drive means as claimed in claim 3, wherein the or each bearing is arranged in respective recess in the body, the or each recess defining an annular space around the bearing arranged therein and the space being filled by the resiient material.

5. Drive means as claimed in either claim 1 or claim 2, wherein the or each bearing is retained in the body by spring elements acting between the bearing and the body.

6. Drive means as claimed in claim 5, wherein the spring elements retaining the or each bearing in the body comprise an annular bow spring radially and axially biassed relative to the bearing.

7. Drive means substantially as hereinbefore described with reference to either Figure 1 or Figure 2 of the accompanying drawings.

8. Drive means as claimed in any one of the preceding claims, the drive means being an electric motor for an air circulation of an oven.