JP2011114971A - Rotary electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an increase in current unbalance generated by a circulating current flowing through a through bolt and conductive structural components such as brackets during operation and to ensure waterproofing performance inside a rotary electric machine, in a rotary electric machine in which a frame to hold a stator core and the conductive structural components, such as the brackets are fastened by passing the conductive through bolt through a notch or a hole provided in the stator core. <P>SOLUTION: The circulating current flowing through the through bolt 5 and the brackets 3, 4 during operation is cut off by inserting insulating washers 9 between the through bolt 5 passing through the hole 1a provided in the stator core 1 and the brackets 3, 4, and the water proofing performance is simultaneously ensured by allowing the inner diameter tolerance of these insulating washers 9 to have zero or a minus tolerance against the outer diameter of an incomplete screw part 5a of the through bolt 5. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a rotating electrical machine in which a conductive through bolt is passed through a notch or a hole provided in a stator core, and a frame that holds the stator core and a conductive structural part such as a bracket are fastened. The present invention relates to improvement of current imbalance caused by circulating current flowing through a through bolt and a conductive structural part such as a bracket, and waterproof performance of a fastening portion of the conductive structure such as a bracket and the through bolt.

3 is a cross-sectional view of the vicinity of a stator core of a three-phase rotating electrical machine assuming use in a situation where the main use location is exposed to raindrops such as outdoors, FIG. 4 is an enlarged view of the vicinity of the washer 7 of FIG. 3, and FIG. 2 is a cross-sectional view of a washer 8. FIG.
In order to ensure the waterproof performance between the frame 2 and the brackets 3 and 4, a sealant is applied to the fitting surface between the frame 2 and the brackets 3 and 4, and a small washer is provided between the through bolt 5 and the bracket 3. 7 and inserting a sealant 7 a between the bracket 3 and the washer 7 and inserting a seal washer 8 between the bracket 4 and the nut 6 to tighten the through bolt 5 and the nut 6. . By applying the sealant 7a to both faces of the washer 7, the clearance between the washer 7 and the through bolt 5 and the clearance between the washer 7 and the bracket 3 is filled with the sealant 7a to ensure waterproof performance. Since the seal washer 8 is composed of a cylindrical rubber portion 8a and a thin steel plate 8b that holds the rubber portion, the rubber portion 8a is compressed by tightening, and the rubber portion 8a, the bracket 4, the through bolt 5, The waterproof performance is secured by the close contact. Needless to say, the positions of the washer 7 and the seal washer 8 may be reversed, and the both sides may be inserted with the washer 7 and coated with the sealant 7a or the seal washer 8.

  In a three-phase rotating electrical machine, it is desirable that the current imbalance be as small as possible. The causes of the current imbalance include voltage imbalance and stator core magnetic circuit imbalance. Among them, a measure that can be implemented in a three-phase rotating electrical machine is to improve the magnetic unbalance of the stator core. The magnetic unbalance of the stator core increases when a notch or a hole is present at a position where the magnetic circuit of the stator core is unbalanced. Further, the conductive through-bolt 5 and the brackets 3 and 4 penetrating the notch and the hole. It also increases when the circulating current flows through the. Of the three-phase rotating electric machine, the notch or hole 1a provided in the stator core is present in an unbalanced position as a magnetic circuit, and it is necessary to pass the bolt 5 through the stator core 1 due to structural restrictions. Some tend to increase current imbalance. It is considered that the current unbalance rate, which is not problematic in practical use of the three-phase rotating electric machine, is preferably 5% or less. However, if it exceeds 5%, a measure for suppressing the current unbalance is required.

  Further, a conductive through bolt 5 is passed through a notch or hole 1a provided in the stator core 1, and the frame 2 holding the stator core 1 and the conductive structural parts such as brackets 3 and 4 are fastened. In the three-phase rotating electric machine, the circulating current flowing through the bolts 5 and the conductive structural parts such as the brackets 3 and 4 during operation is interrupted to improve the changing speed of the stator magnetic flux and the stator core 1. A technique for inserting an insulating washer into the through bolt 5 for the purpose of suppressing an increase in heat generation due to an eddy current flowing in the coil is already known, and this technique can improve current imbalance (for example, Patent Documents 1 and 2).

Japanese Utility Model Publication No. 3-48338 (pages 2-6, FIG. 1) Japanese Utility Model Publication No. 5-9146 (paragraphs 0009, 0015, FIGS. 1 and 4)

However, in the three-phase rotating electric machine that is assumed to be used in a situation where the main use location is exposed to raindrops such as outdoors, the seal washer 8 and the washer 7 are used in the prior art shown in FIGS. When the nut 6 is tightened, the nut 6 and the thin steel plate or washer 7 of the seal washer 8 and the bracket 3 come into contact with each other, and even if there is a coating film of insulating paint on the surface of each part, Since a part is peeled off and becomes electrically conductive, a circulating current flows through the through bolt 5 and the brackets 3 and 4 during operation, and the effect of suppressing current imbalance cannot be obtained.
Further, in the prior art in which the insulating washer disclosed in the above publication is inserted into the through-bolt, there is no mention of a function for preventing water from entering between the insulating washer and the through-bolt or the bracket, so that waterproof performance is ensured. I can't.
Therefore, in the prior art, it is impossible to achieve both improvement of current imbalance due to interruption of circulating current and securing of waterproof performance.

In addition, when the sealing agent 7a is applied between the washer 7 and the bracket 3, the waterproofing performance is improved because the application amount and the application range of the sealing agent 7a vary depending on the level of proficiency of the operator. Quality is not stable.
Further, nitrile rubber is used as the rubber 8a of the seal washer 8 in the prior art. Since the usable temperature range is -50 ° C to 120 ° C, a three-phase rotating electric machine in which the surface temperature of the through bolt hole portion of the bracket 4 exceeds 120 ° C achieves both heat resistance and waterproofness. I can't.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a rotating electrical machine capable of achieving both improvement of current imbalance due to interruption of circulating current and securing of waterproof performance.

  Another object of the present invention is to provide a rotating electrical machine that can achieve both improvement in current imbalance and securing waterproof and heat resistant performance.

  In order to achieve the above-described object, the rotating electrical machine of the present invention has conductive frames such as a frame and a bracket that hold the stator core by passing conductive through bolts through notches and holes provided in the stator core. In a three-phase rotating electrical machine that is fastened with a conductive structural part, a conductive structure such as a through-bolt and a bracket is used to cut off a circulating current that flows through the conductive structural part such as a through-bolt and a bracket during operation. Insert an insulating washer between parts to electrically separate through bolts and conductive structural parts such as brackets, and rotate three-phase through through holes for through bolts provided in conductive structural parts such as brackets. In order to prevent water from entering the inside of the electric machine, the inner diameter of the insulating washer is made to pass from the zero to a negative tolerance with respect to the outer diameter of the incomplete screw portion of the bolt.

  In the rotating electrical machine of the present invention, the surface temperature of the through bolt fastening portion of the conductive structural part such as the bracket is increased to 260 ° C by using the material of the insulating washer inserted between the through bolt and the conductive structural part such as the bracket. Even in such a case, the glass fiber-containing PTFE can be used and has high resistance to deterioration against direct sunlight.

  According to the rotating electrical machine of the present invention, an insulating washer having a negative tolerance from zero with respect to the outer diameter of the incomplete screw portion of the bolt is inserted between the through bolt and the conductive structural part such as the bracket. By electrically separating the conductive structural parts such as the brackets, the circulating current flowing through the conductive bolts and the conductive structural parts such as the brackets during operation can be cut off, and the current imbalance can be improved. Also, the through bolt and the insulating washer are tightened, and the conductive structural parts such as the bracket and the insulating washer are in close contact with each other by fastening the through bolt to prevent water from entering the three-phase rotating electrical machine. it can.

  Further, according to the rotating electrical machine of the present invention, the insulating washer inserted between the through bolt and the conductive structural part such as the bracket is made of PTFE containing glass fiber, so that the through bolt of the conductive structural part such as the bracket or the like is used. Even when the surface temperature of the service hole rises to 260 ° C., the effect described in the first invention can be realized. Moreover, since the glass fiber-containing PTFE has a strong resistance to deterioration against direct sunlight, the waterproof performance can be maintained for a longer period than the nitrile rubber used in the prior art.

It is sectional drawing of the stator core vicinity of the three-phase rotary electric machine which concerns on Example 1 of this invention. FIG. 2 is an enlarged cross-sectional view in the vicinity of an insulating washer on a nut side illustrated in FIG. 1. It is sectional drawing of the stator core vicinity of the conventional three-phase rotary electric machine supposing the use in the condition where the main use place is exposed to raindrops, such as outdoors. FIG. 4 is an enlarged cross-sectional view of the vicinity of the washer side shown in FIG. 3. It is sectional drawing of the seal washer described in FIG.

Example 1.
Hereinafter, a first embodiment of a three-phase rotating electrical machine according to the present invention will be described in detail with reference to FIGS. Note that the present invention is not limited to the embodiments.
1 is a sectional view showing the vicinity of a stator core of a three-phase rotating electrical machine according to Embodiment 1 of the present invention, and FIG. 2 is a section showing the vicinity of an insulating washer on the nut side of the three-phase rotating electrical machine according to Embodiment 1 of the present invention. It is an enlarged view.
In FIG. 1, when the frame 2 holding the stator core 1 and the brackets 3 and 4 are fastened by passing the conductive through bolts 5 through holes 1 a provided in the stator core 1, Glass fiber-containing PTFE (polytetrafluoroethylene) having a large diameter portion and a small diameter portion between the brackets 3 and 4, between the bracket 3 and the head of the through bolt 5, and between the bracket 4 and the spacer 10. Each of the annular insulating washers 9 made of metal is inserted. The insulating washer 9 has an L-shaped cross section, and the small diameter portion enters the through bolt hole of the brackets 3 and 4, and makes contact between the through bolt 5 and the inner surface of the through holes for the through bolts of the brackets 3 and 4. It also prevents. Further, the inner diameter tolerance of the insulating washer 9 is manufactured from zero to a minus tolerance with respect to the outer diameter of the incomplete thread portion 5a of the through bolt 5. On the nut side, as shown in FIG. 2, a spacer 10 is inserted so that the nut 6 can be securely fastened by a complete screw portion.
When the stator core 1 is provided with a notch in place of the hole 1a, and the frame 2 holding the stator core 1 and the brackets 3 and 4 are fastened by passing through a conductive through bolt 5 in the notch. There is also.

As a result, it is possible to prevent the through bolt 5 and the brackets 3 and 4 from coming into direct contact with each other, so that the circulating current flowing through the through bolt 5 and the brackets 3 and 4 is cut off during operation, and the current imbalance of the three-phase rotating electrical machine In addition, the incomplete threaded portion 5a of the through-bolt 5 and the insulating washer 9 can be tightened to provide waterproof performance. Further, the insulating washer 9 and the brackets 3 and 4 can be brought into close contact with each other by the fastening force of the through bolt 5 and the nut 6 to obtain waterproof performance.
In FIG. 1, since the material of the insulating washer 9 is glass fiber-containing PTFE, even in a three-phase rotating electrical machine in which the surface temperature of the through-bolt hole increases to 260 ° C., current imbalance is improved and direct sunlight Even when exposed to water, the waterproof performance can be maintained for a longer period than the nitrile rubber used in the prior art.

  In addition, when 440V 60Hz was applied, with respect to the 0.4kW 4 pole 400V class rotary electric machine whose current imbalance rate was 5 to 6%, the insulating washer 9 shown in Embodiment 1 of the present invention was passed through the bolt. When inserted between the brackets, the current unbalance rate could be improved to 3-4%.

  The present invention is suitable for use as a rotating electric machine used in a situation where it is exposed to raindrops such as outdoors.

  1 Stator Iron Core, 1a Hole for Passing Through Bolt of Stator Core, 2 Frame, 3 Bracket, 4 Bracket, 5 Through Bolt, 5a Incomplete Threaded Part of Through Bolt, 6 Nut, 9 Insulating Washer, 10 Spacer

Claims (3)

  In a rotating electrical machine in which a conductive through bolt is passed through a notch or a hole provided in a stator core and a frame that holds the stator core and a conductive structural part such as a bracket are fastened, the through bolt and the bracket An insulating washer that electrically insulates the two is inserted between the conductive structural parts such as, and the inner diameter of the insulating washer is changed from zero to a negative tolerance with respect to the outer diameter of the incomplete thread portion of the through bolt. Rotating electric machine characterized by that.   The insulating washer is also interposed between the head of the through-bolt and a conductive structural part such as a bracket, and between a nut or spacer screwed to the through-bolt and a conductive structural part such as a bracket. The rotating electrical machine according to claim 1, wherein the rotating electrical machine is one.   The rotating electrical machine according to claim 1, wherein the insulating washer is made of PTFE containing glass fiber.

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