JP4106763B2 - Rotating electric machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotating electrical machine using a rolling bearing as a bearing, and more particularly to a rotating electrical machine such as an AC motor suitable as an inverter-driven induction motor.
[0002]
[Prior art]
When a conventional AC motor is driven by an inverter or the like, a ripple voltage generated by the inverter generates a shaft voltage due to electrostatic induction between the rotating shaft and the bearing of the AC motor, and this shaft voltage adversely affects various control devices. There are also problems such as local discharge inside the bearing and bearing damage.
[0003]
FIG. 5 is a structural sectional view of a rotating electrical machine disclosed in Japanese Utility Model Laid-Open No. 2-33569 as a conventional rotating electrical machine.
In the figure, 51 is a stator in which a coil is wound around a slot portion of a stator core in which a large number of metal materials such as thin steel plates are laminated, and 52 is a rotation that faces the stator 51 through a slight gap. , 53 is a rotating shaft for fitting and fixing the rotor 52 to the outer diameter portion, 54 is a bearing fitted to the rotating shaft 53, 55 is a housing portion that supports the bearing 54 and rotatably supports the rotating shaft 53. It is an outer frame having 55a.
[0004]
Reference numeral 56 denotes an auxiliary bearing fitted into the small-diameter portion 53a at the shaft end portion on the non-load side of the rotary shaft 53, and conductive grease is enclosed therein. Reference numeral 57 denotes a mounting plate made of a conductive material such as iron, and the outer diameter portion of the auxiliary bearing 56 is fitted therein. Further, the mounting plate 57 is fixed to the outer frame 55 with screws.
[0005]
With the above configuration, the rotating shaft 53 and the outer frame 55 are electrically coupled via the auxiliary bearing 56 filled with conductive grease, and have a grounding action. As a result, even during the inverter operation, a potential difference hardly occurs between the rotating shaft 53, the bearing 54, and the outer frame 55, and the shaft voltage can be reduced.
[0006]
[Problems to be solved by the invention]
In the conventional rotating electric machine as described above, an auxiliary bearing filled with conductive grease is arranged at the end of the rotating shaft and is configured to be grounded through the auxiliary bearing. There is a problem that the cost is increased because a special auxiliary bearing in which conductive grease is enclosed is required, and the rotating electric machine uses both shaft ends because the auxiliary bearing is disposed at the end of the rotating shaft. There was also a problem that could not be used.
[0007]
The present invention has been made in order to solve the above-described problems. With a simple structure, the shaft voltage generated between the rotating shaft and the bearing is grounded to the ground, and the electric conduction between the rotating shaft and the bracket is performed. An object of the present invention is to obtain a rotating electrical machine capable of maintaining the stability for a long period of time. Another object of the present invention is to provide a rotating electrical machine that can maintain the electrical conductivity between the rotating shaft and the bracket for a long period of time even in the rotating electrical machine that uses both shaft ends.
[0008]
[Means for Solving the Problems]
In the rotating electrical machine of the present invention, a stator in which a coil is wound, a frame for fixing the stator, a rotor facing the stator with a slight gap, and the rotor are fixed, In a rotating electrical machine having a rotating shaft that is rotatably supported via a rolling bearing, and a bearing bracket that supports the rolling bearing, the rotating shaft is in contact with an outer wall surface opposite to the bearing of the bearing bracket. And a space between the outer wall surface of the bearing bracket opposite to the bearing and the seal packing or a space between the rotary shaft and the seal packing is filled with conductive grease. Thus, an oil reservoir is formed.
[0009]
Also, the set only the concave portion in a part of the bearing opposite the axial through-portion thickness of the bearing bracket, concave provided in a part of the bearing opposite the axis penetrating portion thick portion of the bearing bracket An oil sump is formed by filling conductive grease in a space between the portion, the rotating shaft, and the seal packing.
[0010]
A concave portion is formed on a surface of the seal packing that faces the bearing bracket, and an oil sump is formed by filling conductive grease in a space between the concave portion of the seal packing, the bearing bracket, and the rotating shaft. Is.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a structural sectional view of a rotating electrical machine according to an embodiment of the present invention. In the figure, 1a is an AC motor as a rotating electric machine, 2 is a stator around which a coil is wound, 3 is a frame for fixing the stator 2, 4a and 5a are load-side bearings 6 as rolling bearings, and an anti-load side Load-side brackets and anti-load-side brackets as bearing brackets for supporting the bearing 7, 8 a spacer, 9 a preload spring, 10 a rotor facing the stator with a slight gap, and 11 a rotor 10 fixed The rotating shaft is rotatably supported via rolling bearings called a load-side bearing 6 and an anti-load-side bearing 7.
[0015]
20a and 20b are fitted to the rotary shaft 11 so as to be in contact with the outer wall surface of the bearing bracket (load side bracket 4a, anti-load side bracket 5a) opposite to the bearing (load side bearing 6, anti-load side bearing 7). Seal packing 21 to be combined, conductive grease 21, 22 a, 22 b are shaft-through portion thick portions of bearing brackets (load side bracket 4 a, anti-load side bracket 5 a) and bearings (load side bearing 6, anti-load side bearing 7 ) Is a recess provided in a part facing the rotating shaft 11 on the opposite side.
[0016]
The space surrounded by the concave portion 22a provided in the portion facing the rotating shaft 11 of the thick portion of the through-shaft portion of the load side bracket 4a, the rotating shaft 11, and the seal packing 20a is used as an oil reservoir, or the anti-load side bracket. An encapsulating of conductive grease 21 with the space surrounded by the concave portion 22b provided in the portion facing the rotating shaft 11 of the thick shaft through portion 5a, the rotating shaft 11 and the seal packing 20b as an oil reservoir. It is.
[0017]
The conductive grease 21 fills the portion 23a (or 23b (not shown)) of the load-side bracket 4 (or the anti-load-side bracket 5) of the shaft-passing portion thick portion facing the rotating shaft 11 and provides resistance therebetween. The shaft can be prevented from being charged by lowering the conductive shaft between the rotating shaft 11 and the load side bracket 4a (or the anti-load side bracket 5a).
[0018]
When the seal packing 20a (or 20b) is made of conductive rubber, a portion 24a (or 24b (not shown)) facing the load side bracket 4a (or the anti-load side bracket 5a) of the seal packing 20a (or 20b). )), The resistance during this period is lowered, and the rotating shaft 11 and the load side bracket 4a (or the anti-load side bracket 5a) are made conductive to prevent the shaft from being charged.
[0019]
Since the conductive grease 21 in the recesses 22a and 22b gradually oozes into the 23a and 23b portions or the 24a and 24b portions, the conductive state can be stably maintained for a long time.
Moreover, the conductive grease 21 can be easily replenished by removing the seal packing 20.
[0020]
Embodiment 2. FIG.
FIG. 2 is a structural cross-sectional view of a rotating electrical machine according to an embodiment of the present invention. In the figure, 2, 3, 6-11, and 21 are the same as those in FIG.
1b is an AC motor as a rotating electric machine, and 4b and 5b are load side brackets and anti-load side brackets as bearing brackets. Further, 25a and 25b are fitted to the rotary shaft 11 so as to be in contact with the outer wall surface of the bearing bracket (load side bracket 4b, anti-load side bracket 5b) opposite to the bearing (load side bearing 6, anti-load side bearing 7). The seal packings 26a and 26b to be combined are recesses provided on the surfaces of the seal packings 25a and 25b facing the bearing brackets (the load side bracket 4b and the anti-load side bracket 5b).
[0021]
A space surrounded by the load side bracket 4b, the rotary shaft 11, and the recess 26a provided on the surface facing the load side bracket 4b of the seal packing 25a is used as an oil reservoir, or the anti-load side bracket 5b and the rotary shaft 11 are enclosed. And a space surrounded by a recess 26b provided on the surface of the seal packing 25b opposite to the anti-load side bracket 5b, is filled with conductive grease 21.
[0022]
In the first embodiment, the recesses 26a and 26b are provided on the load side bracket 4a (or the anti-load side bracket 5a) side. However, in this embodiment, the recesses 26a and 26b are provided on the seal packings 25a and 25b side. It is provided.
In this embodiment, charging of the shaft can be easily prevented by adding seal packings 25a and 25b provided with recesses 26a and 26b to an AC motor having a standard structure.
[0023]
Embodiment 3 FIG.
FIG. 3 is a sectional view of the structure of the rotating electrical machine according to the embodiment of the present invention. In the figure, 2, 3, 6-11, and 21 are the same as those in FIG.
1c is an AC motor as a rotating electric machine, and 4c and 5c are load side brackets and anti-load side brackets as bearing brackets. 27a and 27b are concave portions provided in a part of the thick part of the shaft-passing portion of the load side bracket 4c (or the anti-load side bracket 5c), and 28a and 28b are the load side bracket 4c (or the anti-load side bracket 5c). It is a grease supply port provided on the outer wall surface.
[0024]
In the first embodiment, rotation of a partial recess on the opposite side of the bearing (load-side bearing 6, anti-load-side bearing 7) at the shaft penetration portion thick portion of the bearing bracket (load-side bracket 4 a, anti-load-side bracket 5 a). In the example where the recesses 22a and 22b are provided in the portion facing the shaft 11, and the space surrounded by the recesses 22a and 22b, the rotating shaft 11 and the seal packings 20a and 20b is an oil reservoir, and in the second embodiment, Recesses 26a, 26b are provided on the surfaces of the seal packings 25a, 25b facing the bearing brackets (load bracket 4b, anti-load bracket 5b). The recesses 26a, 26b, the rotary shaft 11, the bearing bracket (load bracket) 4b, the space surrounded by the anti-load side bracket 5b) is shown as an oil reservoir, but in this embodiment, a bearing bracket (load side bracket) Recesses 27a and 27b are provided in a part of the shaft through portion thick portion of the rack 4c and the anti-load side bracket 5c), and a space surrounded by the recesses 22a and 22b and the rotating shaft 11 is used as an oil reservoir. .
[0025]
The oil sump for enclosing the conductive grease 21 is surrounded by the rotating shaft 11 and the recesses 22a and 22b provided in a part of the shaft through portion thick portion of the bearing bracket (load side bracket 4c, anti-load side bracket 5c). By configuring the bearing bracket (load side bracket 4c, anti-load side bracket 5c) as special parts, an oil sump can be constructed without adding other parts.
In addition, by providing the grease supply ports 28a and 28b, the conductive grease 21 can be easily supplied.
[0026]
Embodiment 4 FIG.
FIG. 4 is a sectional view of the structure of the rotating electrical machine according to the embodiment of the present invention. In the figure, 2, 3, 6-11, and 21 are the same as those in FIG.
1d is an AC motor as a rotating electric machine, 4d and 5d are load side brackets and anti-load side brackets as bearing brackets, 29a and 29b are bearings (load side bearings) of the bearing brackets (load side bracket 4d and anti load side bracket 5d) 6, seal packing fixed to the outer wall surface on the opposite side to the non-load side bearing 7), 30a is a recess provided in a part of the thick part of the shaft penetration part of the seal packing 29a, and 30b is the part of the shaft penetration of the seal packing 29b. It is a recess provided on a part of the thick part or on the surface facing the shaft end of the rotating shaft 11.
[0027]
A space surrounded by the outer wall surface of the load side bracket 4d, the rotating shaft 11, and the concave portion 30a provided in a part of the thick part of the shaft penetration portion of the seal packing 29a is used as an oil reservoir, or the anti-load side bracket 5d The space surrounded by the rotating shaft 11 and a part of the shaft penetration partial thick part of the seal packing 29b or the recess 30b provided on the surface facing the shaft end of the rotating shaft 11 is used as an oil reservoir, and the conductive grease 21 Is enclosed.
[0028]
Although the seal packings 20a and 20b of the first embodiment and the seal packings 25a and 25b of the second embodiment are shown fitted to the rotary shaft 11, the seal packings 29a and 29b of this embodiment are arranged on the load side. It is fixed to the bracket 4d and the anti-load side bracket 5d.
[0029]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
[0030]
A stator around which a coil is wound, a frame for fixing the stator, a rotor facing the stator through a slight gap, and the rotor are fixed and rotatably supported via a rolling bearing. A rotating electrical machine having a rotating shaft and a bearing bracket that supports a rolling bearing , comprising: a seal packing fitted to the rotating shaft so as to be in contact with an outer wall surface opposite to the bearing of the bearing bracket; Since the oil sump is formed by filling the space between the outer wall surface on the opposite side of the bearing of the bearing bracket and the seal packing or the space between the rotary shaft and the seal packing , a simple structure Thus, it is possible to obtain a rotating electrical machine capable of grounding the shaft voltage generated between the rotating shaft and the bearing to the ground and maintaining the conductivity between the shaft and the bracket for a long period of time. Also, in a rotating electrical machine that uses both shaft ends, the conductivity between the rotating shaft and the bearing bracket can be kept stable for a long period of time.
[0031]
In addition, a seal packing fitted to the rotating shaft so as to come into contact with the outer wall surface on the opposite side of the bearing of the bearing bracket, and a recess provided on a part of the bearing bracket on the opposite side to the bearing at the thick part of the shaft penetrating portion. Since the oil reservoir is formed by filling the space between the part and the rotating shaft with conductive grease, the conductivity between the rotating shaft and the bearing bracket can be kept stable for a long time, and the seal packing is removed. Thus, the conductive grease can be easily replenished.
[0032]
And a seal packing fitted to the rotary shaft so as to be in contact with the outer wall surface of the bearing bracket opposite to the bearing, the concave portion formed on the surface of the seal packing facing the bearing bracket, the bearing bracket, and the rotary shaft. Since the oil sump is formed by filling the space between the conductive grease, it is possible to easily prevent the rotating shaft from being charged by adding a seal packing provided with a recess to the rotating electrical machine of the standard structure. .
[Brief description of the drawings]
FIG. 1 is a structural sectional view of a rotating electrical machine according to an embodiment of the present invention.
FIG. 2 is a structural cross-sectional view of a rotating electrical machine according to an embodiment of the present invention.
FIG. 3 is a structural cross-sectional view of a rotating electrical machine according to an embodiment of the present invention.
FIG. 4 is a structural sectional view of a rotating electrical machine according to an embodiment of the present invention.
FIG. 5 is a structural sectional view of a rotating electrical machine disclosed in Japanese Utility Model Laid-Open No. 2-33569 as a conventional rotating electrical machine.
[Explanation of symbols]
1a, 1b, 1c, 1d AC motor, 2 stator, 3 frame, 4a, 4b, 4c, 4d load side bracket, 5a, 5b, 5c, 5d anti load side bracket, 6 load side bearing, 7 anti load side bearing , 8 Spacer, 9 Preload spring, 10 Rotor, 11 Rotating shaft, 20a, 20b Seal packing, 21 Conductive grease, 22a, 22b Partial rotating shaft on the opposite side of the bearing in the shaft penetration part thick part of the bearing bracket 23a, a concave portion provided in a portion facing the surface 23a, a portion facing the rotating shaft 11 of a shaft-through portion thick portion of the load side bracket 4, 24a, a portion facing the load side bracket 4a of the seal packing 20a, 25a, 25b bearings Seal packing fitted to the rotary shaft 11 so as to come into contact with the outer wall surface on the side opposite to the bearing of the bracket; 26a, 26b 25a, 25b, a recess provided on the surface of the bearing bracket facing the bearing bracket, 27a, 27b, a recess provided in a part of the shaft penetration portion thick part of the bearing bracket, 28a, 28b, grease provided on the outer wall surface of the bearing bracket Replenishment port 29a, 29b seal packing for fixing to the outer wall surface opposite to the bearing of the bearing bracket, 30a seal packing 29a, a recess provided in a part of the thick part of the shaft penetration part, 30b seal packing 29b shaft penetration Recesses provided on a part of the partial thick part or on the surface facing the shaft end of the rotating shaft 11, 51 stator, 52 rotor, 53 rotating shaft, 54 bearing, 55 outer frame, 56 auxiliary bearing, 57 mounting plate .

Claims (3)

A stator around which a coil is wound, a frame for fixing the stator, a rotor facing the stator with a slight gap, and the rotor is fixed and freely rotatable via a rolling bearing. In a rotating electrical machine having a rotating shaft supported by a bearing bracket and a bearing bracket that supports the rolling bearing,
A seal packing that is fitted to the rotary shaft so as to come into contact with an outer wall surface opposite to the bearing of the bearing bracket, and a space between the outer wall surface opposite to the bearing of the bearing bracket and the seal packing; An electric rotating machine characterized in that an oil reservoir is formed by filling conductive grease in a space between the rotating shaft and the seal packing . The only set a recessed portion in a part of the bearing opposite the axial through-portion thickness of the bearing bracket, the bearing in the axial through-portion thickness portion of the bearing bracket and the recessed portion provided in a part of the opposite side The rotating electrical machine according to claim 1, wherein an oil sump is formed by filling conductive grease in a space between the rotating shaft and the seal packing. A concave portion is formed on a surface of the seal packing that faces the bearing bracket, and an oil sump is formed by filling conductive grease in a space between the concave portion of the seal packing, the bearing bracket, and the rotating shaft. The rotating electrical machine according to claim 1.

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