JP3779558B2 - Insulator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an insulator, and more particularly to a low noise insulator suitable for use in a current collector for a railway vehicle that travels at high speed.
[0002]
[Prior art]
Since the aerodynamic noise accompanying the increase in the speed of the railway vehicle increases in proportion to the sixth to eighth power of the speed, it rapidly increases as the vehicle speed increases. On the other hand, the demand for environmental conservation is expected to increase in the future. For this reason, in vehicles that run at high speeds, it is required to reduce the noise of the current collector, which is the main aerodynamic sound source, and the insulator, which is a component of the current collector, is also an important component for reducing noise. is there.
[0003]
Conventionally, as an insulator for a railway vehicle, an insulator in which a plurality of shades are provided on a cylindrical insulator body is generally used.
[0004]
Japanese Unexamined Patent Publication No. 8-336203 is known as a low-noise insulator for high-speed vehicles. This is because the surface leakage distance of the insulator in the direction perpendicular to the train travel is increased by the cage provided on the shade surface of the conventional insulator in the train travel direction, thereby reducing the diameter of the insulator in the direction perpendicular to the train travel of the insulator. It is intended to reduce the air resistance during high-speed driving and to reduce aerodynamic noise.
[0005]
Japanese Patent Laid-Open No. 8-322102 is also available. This is because a surface roughness element is arranged on the entire surface of the shade of a conventional insulator to suppress acoustic resonance generated between the shades, thereby reducing noise.
[0006]
In addition, as a known technique of other shape insulators, [No. 96-51] The 51st Transportation and Logistics Division Annual Proceedings of the Japan Society of Mechanical Engineers, pages 381-382, ellipse or ellipse shape insulators An insulator with a structure in which a plurality of shades are provided on the earth has been announced.
[0007]
[Problems to be solved by the invention]
The object of the present invention is to reduce the aerodynamic noise during high-speed running while having the electrical insulation performance necessary for use in a railway vehicle current collector by means other than the above-mentioned known low-noise insulator. The object is to provide an insulator with low noise.
[0008]
[Means for Solving the Problems]
A feature of the present invention is that the cross-sectional shape of an insulator formed by arranging a barrel and a plurality of stages of shades around the barrel in the longitudinal direction is an ellipse or an ellipse, and has three or more types of shade diameters. A small-diameter shade is arranged adjacent to the large-diameter shade, a medium-diameter shade is arranged adjacent to the small-diameter shade, the small-diameter shade is arranged on both sides of the medium-diameter shade, and the large-diameter shade is arranged. The shades of medium diameter, shades of medium diameter, and shades of small diameter are alternately and repeatedly arranged, and the groove formed on the trunk circumference between the shades has a U-shaped cross section. The space between the shades is made small while securing the space insulation distance between the tops of the shades. In addition, when the insulator is an ellipse or an ellipse, the area in the circumferential direction increases, so that the insulation resistance of the insulator as a whole decreases. To prevent this, the shade density is increased, the surface leakage distance of the insulator is increased, and the insulation performance of the insulator is ensured. Furthermore, the speed increasing function of the airflow at the circumferential part of the insulator trunk at the bottom of the shade bottom is suppressed , and the projection is provided on the shaded face parallel to the major axis direction of the ellipse or ellipse and on the outer circumferential side from the trunk. By suppressing the separation of the flow between the shades, the vortex area behind the insulator is controlled and the vortex diameter is reduced to reduce noise.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a front view of a conventional insulator 1 and FIG. 2 shows a side view thereof. The direction of axis A is the traveling direction of the train. FIG. 3 shows a cross section II of FIG. FIG. 4 shows a section II-II in FIG.
[0010]
In FIG. 3, the simulation result of the flow in the height position between the shades corresponding to the cross-section II by the computer when the insulator of the prior art is placed in the air flow having the same flow velocity as the vehicle speed (about 350 km / h) The outline of is shown. Based on this result, the flow between a pair of shades is considered.
[0011]
According to fluid dynamics textbooks (eg, Mitsuo Makino, “Fluid Resistance and Streamlined” Industrial Book Co., Ltd.), the flow along the cylinder surface increases in speed and may flow faster than the main flow velocity. It is taught that the speed does not increase in the flow along. As shown in FIG. 3, when the analysis result of the flow between the caps is observed with respect to the insulator having an elliptical cross section by an electronic computer, a portion 101 faster than the main flow velocity 102 is generated in the vicinity of the elliptical cylinder surface, that is, the insulator body surface, and gradually grows. It has been found that when the entire diameter of the cocoon is reached, separation occurs on the body surface and a reverse flow region 104 is generated.
[0012]
In addition, a strong vorticity due to the flow velocity distribution is latent inside the boundary layer of the flow, and a vortex having an axis in a direction perpendicular to the main flow as seen from the rear of the air flow in section II-II in FIG. An example of a simulation result of a vorticity distribution (hereinafter referred to as a horizontal vortex) is shown.
[0013]
The strong vorticity region 105 in FIG. 4 grows around the circumference of the insulator trunk, and immediately after peeling off from the trunk, moves to the outer circumference of the shade, and the strong vorticity region 106 in the boundary layer of the shade surface. It is a place that is going to slide around the shade around the shade.
[0014]
While the boundary layer sticks to the body surface and the shade surface, the vorticity can be considered to be hidden in the boundary layer and does not behave as a dynamic vortex. The degree becomes manifest as a dynamic vortex and behaves freely including axis transformation.
[0015]
By such a mechanism, the vortex created in the shade is discharged to the rear of the flow as a vortex train depending on the shade spacing, and these vortex trains are considered to be the main cause of the insulator noise.
[0016]
Thus, it is considered that the strong vorticity region 105 that peels off the main cause of noise in the insulator of the prior art from the insulator body is a trigger and slides on the shade surface together with the strong vorticity region 106 of the shade surface. In order to reduce noise, a means for suppressing this may be provided.
[0017]
FIG. 5 shows a front view of an insulator according to an embodiment of the present invention, and FIG. 6 shows a side view. The direction of axis A is the traveling direction of the train. FIG. 7 shows a section III-III in FIG.
[0018]
FIG. 8 is an enlarged view of the VI part in FIG. In this figure, the shades 11 to 13 and the three types of shades are arranged alternately and repeatedly, and a U-shaped groove shape 14 is provided on the circumference of the insulator body at the bottom of the shade. It is set as the shape which connected and arranged 11-13. As shown in FIG. 8, the shade 11 to 13 has the largest shade diameter of the shade 11, the shade 12 is smaller than the shade 11, the shade 13 is smaller than the shade 12, and the shade 13 has the smallest shade diameter. It has become. A shade 13 is disposed adjacent to the shade 11, and a shade 12 is disposed adjacent to the shade 13. Further, the shade 13 is arranged on both sides of the shade 12. In this way, the small-diameter shade 13 is arranged adjacent to the large-diameter shade 11, the medium-diameter shade 12 is arranged adjacent to the shade 13, and the small-diameter shade 13 is arranged on both sides of the medium-diameter shade 12. The arrangement of the shades 11 to 13 is repeated.
[0019]
By making the cross-sectional shape of the insulator an ellipse or an ellipse, it is possible to smooth the change in the curvature of the cylindrical part, delay the peeling on the body surface, and narrow the range of vortex flow behind the insulator. As a result, it is effective in reducing the insulator noise. Furthermore, in the present invention, by reducing the area of the insulator body surface between the shades while ensuring the insulation performance, the flow velocity of the airflow between the shade shades can be reduced, and noise reduction can be promoted.
[0020]
In other words, three or more types of cocoon shades are used, and these are arranged alternately and repeatedly, so that a space insulation interval (about 50 mm) between the cocoon shade tips with the maximum diameter is secured, and the shade spacing is about 10 to 10 mm. It is about 15 mm or less. As a result, the boundary layer of the insulator body surface is finely divided, and interference with the boundary layer of the shade surface occurs, resulting in a weak flow and a weak vorticity.
[0021]
Furthermore, by making the circumferential part of the insulator body into a U-shaped groove shape 14, the boundary layer on the body surface becomes thick, that is, the vorticity becomes weak and the peeling force also becomes weak.
[0022]
As a result, the vorticity of the vortex train released from Kasama also becomes weaker and the vortex diameter becomes smaller, so that the noise frequency moves to the higher frequency side and the auditory correction effect is also added to reduce the noise sensibly. Is done.
[0023]
Aerodynamic sound produces a loud noise from a vortex near the object, and a small noise from a vortex far from the object, even if the vortex has the same strength. In the present invention, attention is paid to this, and if the separation of the flow is delayed, the distance between the object and the vortex is increased, and as a result, noise is reduced.
[0024]
FIG. 9 is a view in which the projections 21 are attached to the shades 11 and 12 of FIG. 7 in the longitudinal direction of the insulator on the shade surface on the outer peripheral side of the insulator body diameter. The projection 21 is, FIG. 10 (V in Fig. 5 - V cross section), Fig. 11 (IV in FIG. 5 - IV cross section) as, in the train travel direction, is mounted in the longitudinal direction of the insulator.
[0025]
By adopting such a structure, the strong vorticity 105 peeled off on the insulator body surface increases the resistance when the strong vorticity region 106 on the shade surface slid out and slides out. Can be delayed. As a result, the distance between the insulator and the rear vortex region can be increased, which is effective in reducing insulator noise.
[0026]
【The invention's effect】
As described above, according to the present invention, a groove shape having a U-shaped cross section is provided in the insulator barrel circumferential direction on the insulator barrel surface of the shade bottom portion, and the shades having three types of diameter dimensions are alternately and By arranging repeatedly and connecting with a groove, it is possible to suppress the increase in the airflow on the insulator body surface, weaken the vorticity of the flow between the shades, and weaken the peeling force. In addition, by providing a projection on the shade surface in the train running direction, this projection becomes a resistance, and the separation between the insulator body surface and the strong vorticity region of the shade surface can be delayed. The distance can be expanded. As a result, it is possible to reduce aerodynamic noise when the insulator is running at high speed. As a result, a low-noise high-speed railway vehicle current collector can be provided.
[Brief description of the drawings]
FIG. 1 is a front view showing the overall structure of a conventional insulator.
FIG. 2 is a side view showing the overall structure of a conventional insulator.
3 is a cross-sectional view taken along the line II of FIG. 2 showing a flow simulation result by an electronic computer when the insulator of the conventional example is placed in an airflow having the same flow velocity as the vehicle speed.
4 is a cross-sectional view taken along the line II-II in FIG. 2 showing a simulation result of a vorticity distribution of a transverse vortex by an electronic computer of a conventional insulator.
FIG. 5 is a front view showing an overall structure of an insulator according to an embodiment of the present invention.
FIG. 6 is a side view showing the overall structure of an insulator according to an embodiment of the present invention.
7 is a cross-sectional view taken along the line III-III of FIG. 5 showing an embodiment of the present invention.
8 is an enlarged view of a VI part in FIG. 5 showing an embodiment of the present invention.
9 is an enlarged view of a portion VI in FIG. 5 showing a case where a protrusion is attached to the shade of one embodiment of the present invention.
10 is a cross-sectional view taken along the line IV-IV in FIG. 5 showing a case where a protrusion is attached to the shade of one embodiment of the present invention.
11 is a cross-sectional view taken along line V-V in FIG. 5 showing a case where a protrusion is attached to the shade of one embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Conventional insulator 2 ... Insulator 11 ... Shade (large diameter)
12 ... Shade (medium diameter)
13 ... Shade (small diameter)
14 ... U-shaped groove shape 21 ... Protrusion 101 ... Flow speed increasing area 102 ... Flow main flow velocity area 103 ... Flow deceleration area 104 ... Flow reverse flow area 105 ... Strong transverse vortex area 106 grown in the insulator body ... Strong transverse vortex region 107 with a shaded surface ... weak transverse vortex region due to the reverse flow region

Claims (1)

An insulator formed by arranging a barrel and a plurality of shades around the barrel in the longitudinal direction;
The cross-sectional shape of the trunk and the shade is an ellipse or an ellipse,
The shade has three types of diameters, a small-diameter shade is arranged adjacent to the large-diameter shade, a medium-diameter shade is arranged adjacent to the small-diameter shade, The small-diameter shade is arranged on both sides, the large-diameter shade, the medium-diameter shade and the small-diameter shade are repeatedly arranged,
The groove shape formed in the trunk circumference between the shades is a U-shaped cross section,
The shade has a protrusion on its surface,
The said insulator is parallel to the major axis direction of the said ellipse or an ellipse, and is installed in the said shade on the outer peripheral side from the said trunk | drum, The insulator characterized by the above-mentioned.

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