Line bushing and terminal studs with increased ignition gaps

Abstract

The invention relates to a line bushing (1) in a housing (2) of an electrical machine (1) in explosive atmospheres, having a threaded bush (100) and a terminal stud (200), wherein the threaded bush (100) is an insulator and is located in, particularly screwed into, a recess in the housing (2), wherein the terminal stud (200) is made from an electrically conductive material and is provided, at least in sections, with a thread, wherein connection options (206) for lines and braids are provided at either end of the terminal stud (200), wherein the terminal stud (200) can be screwed into the threaded bush (100).

Claims

1. A dynamo-electric machine for explosive environments, comprising: a housing having a threaded recess; and a line bushing made from an electrically conductive material and having a threaded portion and a stop shoulder and opposite ends, each of the opposite ends having a connection option for a line or braid, a threaded bush configured as an insulator and having a shoulder and an external thread with a first thread length for threaded engagement with the threaded recess of the housing, said shoulder and external thread defining a first ignition gap when the threaded bush is screwed into the threaded recess of the housing, and an internal thread with a second thread length for threaded engagement with the threaded portion of a terminal stud, with the second thread length being greater than the first thread length, said stop shoulder in conjunction with the second thread length defining a second ignition gap when the terminal stud is screwed into the threaded bush.

2. The dynamo-electric machine of claim 1, wherein the threaded bush has a thread height and the terminal stud has a thread height which is identical to the thread height of the threaded bush.

3. The dynamo-electric machine of claim 1, wherein the line is embodied as an energy supply line, a sensor line, or a data line.

Description

BRIEF DESCIRPTION OF THE DRAWING

(1) The invention and the advantageous embodiment of the invention are described in greater detail by reference to the following exemplary embodiments; in the figures:

(2) FIG. 1 shows a side view of a threaded bush,

(3) FIG. 2 shows a section through a threaded bush,

(4) FIG. 3 shows a side view of a terminal stud,

(5) FIG. 4 shows a section through a terminal stud,

(6) FIG. 5 shows an assembled state of terminal studs and threaded bush,

(7) FIG. 6 shows a section through the assembled state of terminal studs and threaded bush,

(8) FIG. 7 shows a longitudinal section of a dynamo-electric machine having a line bushing of this type.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(9) FIG. 1 shows a side view of a threaded bush 100, which can be subdivided into several sections. These sections are a lower section 102, a collar 103 and an upper section 104.

(10) The threaded bush 100 is rotationally symmetrical in respect of its axis 109. A male thread 101 is provided in the lower section 102 on a predefinable axial length of said section 102. The threaded bush 100 is fixed in the housing 2 of a dynamo-electric machine 1 via said male thread 101, as illustrated later.

(11) FIG. 2 shows a longitudinal section of the threaded bush 100, with its sections 102, 103 and 104, wherein the threaded bush 100 has a recess 106 in the lower section 102, as well as on a certain predefinable axial section of the collar 103. In the remaining section of the collar 103 as well as in the upper section 104, a further recess is provided, which at least across an axial part of said sections 103 and 104 has a female thread 105.

(12) FIG. 3 shows a terminal stud 200 with a lower section 202 which has a stop shoulder 207 and in a transition to the upper section 204 has a groove 203. Two male threads are provided in the upper section 204. A male thread 201 in the lower part of the upper section 204 and a male thread 205 in the upper part of the upper section 204. Wherein in this embodiment the male thread 201 has a larger diameter than the male thread 205.

(13) FIG. 4 shows, in the longitudinal section of the terminal stud 200 in the lower section 202, a connection option 206 for lines and braids, e.g. for the electrical supply of the dynamo-electric machine. Furthermore, in this representation too, both male threads 205 and 201 are represented in the upper section 204 of the terminal stud 200.

(14) FIG. 5 shows in the assembled state the threaded bush 100 with the terminal stud 200, which has been screwed into the threaded bush 100. The male thread 205 can be seen in the upper section of the terminal stud 200.

(15) FIG. 6 shows, in a longitudinal section of the assembled state according to FIG. 5, the threaded bush 100 and the terminal stud 200. By screwing the terminal stud 200 into the threaded bush 100 or screwing the threaded bush 100 into the terminal stud 200 and the associated stop 207 on the shoulder 108, an ignition gap with its maximum screw reach 14 is formed by the thread 201.

(16) This threaded connection has an axial thread length 15 in the engagement of the terminal stud 200 in the threaded bush 100.

(17) Furthermore, a maximum screw reach 13 of the threaded bush is likewise provided in the housing 2. This threaded connection has an axial thread length 16 in the engagement of the threaded bush 100 in a housing 2.

(18) A lock nut (not shown in greater detail) can be set, e.g. for positioning and fixing, on the male thread 205 in the upper part of the upper section 204 of the terminal stud 200.

(19) In this case the ignition gaps are significantly longer than the axial thread lengths 15, 16 because of the thread configurations known per se. The width of the ignition gap also becomes comparatively narrow thanks to this threaded connection of terminal stud 200 and threaded bush 100 and/or threaded bush 100 and housing 2.

(20) FIG. 7 shows a schematic longitudinal section of a dynamo-electric machine 3. The lines of a terminal box 12 are energy supply lines 6 and/or sensor lines 7, which run as a line bushing 1 through the housing 2 of the dynamo-electric machine 3. Energy supply lines 6 are necessary for the winding system 4 of the dynamo-electric machine 3 and generate an electromagnetic field in the stator 8, and as a result of electromagnetic interactions with a rotor 9 result in a rotation of the shaft 10, which is supported on the housing 2 by bearings 11.

(21) The lines are electrically conductively contacted with the one or more terminal studs 200, which are embodied as electrically conductive.

(22) The threaded bush 100 is made from electrically insulating material.