JP7685451B2 - Overhead line tension balancer - Google Patents

Description

An embodiment of the present invention relates to a tension balancer that can be used on overhead lines.

Overhead wires, such as those used in railways, are fitted with tension balancers as devices for tensioning the wires with the proper tension even when expansion and contraction occurs due to temperature changes. For example, Patent Document 1 discloses a tension balancer whose basic structure consists of multiple cylindrical members arranged coaxially and coil springs arranged between the cylindrical members.

JP 2009-296795 A

One of the objectives of the embodiments of the present invention is to provide a tension balancer with a novel structure. Alternatively, one of the objectives of the embodiments of the present invention is to provide a tension balancer with reduced hysteresis in the stroke-tension characteristics.

One embodiment of the present invention is a tension balancer. This tension balancer includes a first unit, a second unit, a first coil spring, a plurality of first sliding plates, and a plurality of first stoppers. The first unit includes a first cylindrical member having a first end and a second end, a ring-shaped first front washer located on the first end side and surrounded by the first cylindrical member, and a ring-shaped first front spring washer that contacts the second end side of the first front washer and is spaced apart from the first cylindrical member. The second unit includes a second cylindrical member that has a first end exposed from the first cylindrical member and a second end located within the first cylindrical member and is inserted into the first cylindrical member, and a ring-shaped first rear washer that surrounds the second cylindrical member and is located within the first cylindrical member. The first coil spring is located between the first unit and the second unit, surrounds the second cylindrical member, and is sandwiched between the first front spring washer and the first rear washer. The first sliding plates are located between the first coil spring and the first cylindrical member, and a portion of each is sandwiched between the first front spring washer and the first cylindrical member. The first stoppers are sandwiched between adjacent first sliding plates and are configured to restrict the rotation of the first sliding plates.

One embodiment of the present invention is a tension balancer. This tension balancer includes a first unit, a second unit, a first coil spring, a first sliding plate, and a first stopper. The first unit includes a first cylindrical member having a first end and a second end, a ring-shaped first front washer located on the first end side and surrounded by the first cylindrical member, and a ring-shaped first front spring washer that contacts the second end side of the first front washer and is spaced apart from the first cylindrical member. The second unit includes a second cylindrical member that has a first end exposed from the first cylindrical member and a second end located within the first cylindrical member and is inserted into the first cylindrical member, and a ring-shaped first rear washer that surrounds the second cylindrical member and is located within the first cylindrical member. The first coil spring is located between the first unit and the second unit, surrounds the second cylindrical member, and is sandwiched between the first front spring washer and the first rear washer. The first sliding plate is located between the first coil spring and the first cylindrical member, and a portion of each is sandwiched between the first front spring washer and the first cylindrical member. The first stopper is sandwiched between the opposing sides of the first sliding plate when wound cylindrically, and is configured to restrict the rotation of the first sliding plate.

One embodiment of the present invention is a tension balancer. This tension balancer includes a first unit, a second unit, a first coil spring, a first sliding tube, and a first stopper. The first unit includes a first cylindrical member having a first end and a second end, a ring-shaped first front washer located on the first end side and surrounded by the first cylindrical member, and a ring-shaped first front spring washer that contacts the second end side of the first front washer and is spaced apart from the first cylindrical member. The second unit includes a second cylindrical member that has a first end exposed from the first cylindrical member and a second end located within the first cylindrical member and is inserted into the first cylindrical member, and a ring-shaped first rear washer that surrounds the second cylindrical member and is located within the first cylindrical member. The first coil spring is located between the first unit and the second unit, surrounds the second cylindrical member, and is sandwiched between the first front spring washer and the first rear washer. The first sliding tube has a notch and is located between the first coil spring and the first cylindrical member, with a portion of each being sandwiched between the first front spring washer and the first cylindrical member. The first stopper is disposed within the notch of the first sliding tube and is configured to restrict rotation of the first sliding tube.

FIG. 1 is a schematic perspective view of a tension balancer according to an embodiment of the present invention. FIG. 2 is a schematic end view of a tension balancer according to an embodiment of the present invention. FIG. 2 is a schematic end view of a tension balancer according to an embodiment of the present invention. FIG. 2 is a schematic side view of a tension balancer according to an embodiment of the present invention. FIG. 2 is a schematic side view of a tension balancer according to an embodiment of the present invention. 1A to 1C are schematic perspective, side, and front views of a tension balancer according to an embodiment of the present invention. 1A to 1C are schematic side, end and front views of a tension balancer according to an embodiment of the present invention. FIG. 2 is a schematic end view of a tension balancer according to an embodiment of the present invention. FIG. 2 is a schematic perspective view of a sliding plate disposed in the tension balancer according to the embodiment of the present invention. FIG. 2 is a schematic perspective view of a sliding plate disposed in the tension balancer according to the embodiment of the present invention. FIG. 2 is a schematic perspective view of a sliding tube disposed in the tension balancer according to the embodiment of the present invention. 1A to 1C are schematic perspective, end and front views of a tension balancer according to an embodiment of the present invention.

Each embodiment of the invention disclosed in this application will be described below with reference to the drawings. However, the present invention can be embodied in various forms without departing from the spirit of the invention, and should not be interpreted as being limited to the description of the embodiments exemplified below.

In order to clarify the explanation, the drawings may show the width, thickness, shape, etc. of each part in a schematic manner compared to the actual embodiment, but this is merely an example and does not limit the interpretation of the present invention. Furthermore, in this specification and each figure, elements having the same function as those explained in the previous figures may be given the same reference numerals and duplicate explanations may be omitted.

In this specification and drawings, the same reference numeral is used to collectively represent multiple identical or similar components, and a hyphen and a number are added after the reference numeral to represent them individually. When multiple parts of a single component are to be distinguished from one another, the same reference numeral is used, followed by a hyphen and an alphabet.

In this specification and claims, the expression "a structure exposed from another structure" refers to a configuration in which a portion of a structure is not covered by another structure, and includes a configuration in which the portion not covered by the other structure is covered by yet another structure. The configuration expressed by this expression also includes a configuration in which a structure is not in contact with the other structure.

First Embodiment
In this embodiment, a tension balancer 10 according to one embodiment of the present invention will be described. The tension balancer 10 can be used to tension an overhead wire with an appropriate tension.

1. Overall structure FIG. 1 shows a schematic perspective view of the tension balancer 10. The tension balancer 10 includes a plurality of cylindrical units arranged on the same axis and having different outer diameters. There is no restriction on the number of units, which is typically 2 to 4, and may be 5 or more. In the tension balancer 10, a part of a unit having a smaller outer diameter is inserted into a unit having a larger outer diameter. More specifically, when the tension balancer 10 has first to n-th units (n is a natural number of 2 or more) and the outer diameter decreases in the order from the first unit to the n-th unit, the (k+1)-th unit is arranged inside the k-th unit (k is a variable selected from natural numbers of 1 or more (n-1)), and the (k+1)-th unit can reversibly slide inside the k-th unit in the direction of the central axis of each unit. 1 shows a tension balancer 10 having three units (a first unit 100, a second unit 200, and a third unit 300) as a two-stage tension balancer. In the following, the present embodiment will be described mainly using the two-stage tension balancer.

A pole-side mounting member (hereinafter referred to as the first hook) 104 is attached directly or indirectly to one end (second end) of the first unit 100 having the largest outer diameter, and the tension balancer 10 can be connected to a fixed structure such as a pole by using this first hook 104. On the other hand, an overhead line-side mounting member (hereinafter referred to as the second hook) 304 that is connected to the overhead line is attached directly or indirectly to one end of the unit having the smallest outer diameter (here, the third unit 300). As described later, a coil spring is arranged in a compressed state between adjacent units, and the elastic force of the coil spring that tries to expand generates a force that causes the outer unit to pull the adjacent inner unit inward. This force allows the overhead line to be pulled with the appropriate tension.

In the following description, the length direction of the tension balancer 10 is defined as the x direction, and the directions perpendicular to the x direction and perpendicular to each other are defined as the y direction and the z direction. The x direction is parallel to the central axis of the tension balancer 10 and each unit, and is the direction in which the second to nth units slide. FIG. 2 shows a schematic diagram of an end surface along a chain line A-A' extending in the x direction in FIG. 1, and FIG. 3 shows a schematic diagram of an end surface along a chain line B-B' perpendicular to the chain line A-A'. For ease of viewing, the coil springs (first coil spring 140 and second coil spring 142) described later are not shown in FIG. 3.

2. First Unit As shown in FIG. 1 to FIG. 3, the first unit 100 includes a first cylindrical member 102. A cover 106 forming a bottom surface can be provided on the second end side of the first cylindrical member 102 where the first hook 104 is disposed. The first hook 104 is directly attached to the cover 106 by welding. The first cylindrical member 102 may also be provided with an opening for suspending the first cylindrical member 102 when assembling the tension balancer 10, or an opening for draining water that has infiltrated inside. The second end side is further provided with a falling-off prevention mechanism for preventing the second unit 200 and the third unit 300 from falling off. There are no restrictions on the structure of the falling-off prevention mechanism, and in the example shown in FIG. 1, a U-shaped bar 114 is provided as the falling-off prevention mechanism. The U-shaped bar 114 extends in a direction perpendicular to the z direction and penetrates the first cylindrical member 102, and a collar 116 provided at the end of the U-shaped bar 114 prevents the U-shaped bar 114 from falling off. The restoring forces of the first coil spring 140 and the second coil spring 142 move the lid body 106 toward the second end, but the movement is restricted by the U-shaped bar 114.

A ring-shaped first front washer 110 is provided at the other end (first end) of the first cylindrical member 102, which faces the second end. The first front washer 110 can be provided so as to be surrounded by the first cylindrical member 102, and closes a part of the first end of the first cylindrical member 102. The opening of the first front washer 110 serves as an opening through which the second unit 200 slides within the first unit 100 and a part of it is exposed from the first unit 100. Although not shown, the first front washer 110 may not surround the first cylindrical member 102, and may have an outer diameter that is the same or substantially the same as the outer diameter of the first cylindrical member 102. The first front washer 110 may also be integrated with the first cylindrical member 102.

A ring-shaped first front spring washer 112 that surrounds the second unit 200 is further provided on the first end side of the first cylindrical member 102. The first front spring washer 112 is disposed on the second end side of the first front washer 110 and is in contact with the first front washer 110.

Here, the first front spring washer 112 is configured so that its outer diameter is smaller than the outer diameter of the first front washer 110 and smaller than the inner diameter of the first cylindrical member 102. Therefore, a gap exists between the first front spring washer 112 and the first cylindrical member 102, and they do not contact each other. The gap between the first front spring washer 112 and the first cylindrical member 102 is set so that the first sliding plate 120 described later can be inserted between them. Specifically, although it depends on the wire diameter of the first coil spring 140, the outer diameter of the first front spring washer 112 and the inner diameter of the first cylindrical member 102 are set to be, for example, 1 mm to 3 mm or 1 mm to 2 mm.

On the other hand, the inner diameter of the first front washer 110 is larger than the inner diameter of the first front spring washer 112. Therefore, the first front spring washer 112 comes into contact with the outer surface of the second cylindrical member 202, which will be described later.

The first cylindrical member 102, the first front washer 110, and the first front spring washer 112 each contain a metal material such as iron, aluminum, or stainless steel. Preferably, these members are formed using stainless steel, which has high strength and low corrosion resistance. The surfaces of the second end side and the second cylindrical member 202 side of the first front spring washer 112 may each be formed with a coating layer to reduce friction between the first coil spring 140 and the second cylindrical member 202. Similarly, a coating layer may also be provided on the second end side and the surface of the second cylindrical member 202 side of the first front washer 110. Examples of the coating layer include a diamond-like carbon (DLC) film, a hard chrome plating film, a titanium nitride film, a film of a fluorine-containing polymer such as polytetrafluoroethylene, or a film of an engineering plastic. On the other hand, the surface of the first end side of the first front washer 110 and the outer surface of the first cylindrical member 102 may be subjected to hot-dip galvanization or hot-dip aluminum plating.

3. Second Unit The second unit 200 is inserted entirely or partially into the first unit 100. The second unit 200 may have a structure similar to that of the first unit 100. Specifically, the second unit 200 includes a second cylindrical member 202 having an outer diameter smaller than the inner diameter of the first cylindrical member 102, and a ring-shaped second front washer 210 is provided at one end (first end) exposed from the first cylindrical member 102. The second front washer 210 may be provided so as to be surrounded by the second cylindrical member 202, and closes a part of the first end of the second cylindrical member 202. The opening of the second front washer 210 serves as an opening through which the third unit 300 slides inside the second unit 200 and a part of it is exposed from the second unit 200. Although not shown, similar to the first unit 100, the second front washer 210 may not surround the second cylindrical member 202 and may have an outer diameter that is the same or substantially the same as the outer diameter of the second cylindrical member 202. Also, the second front washer 210 may be integral with the second cylindrical member 202.

A ring-shaped second front spring washer 212 that surrounds the third unit 300 is further provided on the first end side of the second cylindrical member 202. The second front spring washer 212 is disposed on the second end side of the second front washer 210 and is in contact with the second front washer 210.

As with the first unit 100, the second front spring washer 212 is configured so that its outer diameter is smaller than that of the second front washer 210 and smaller than the inner diameter of the second cylindrical member 202. Therefore, there is a gap between the second front spring washer 212 and the second cylindrical member 202, and they do not contact each other. The gap between the second front spring washer 212 and the second cylindrical member 202 is also set so that the second sliding plate 122 described later can be inserted between them. Specifically, the outer diameter of the second front spring washer 212 and the inner diameter of the second cylindrical member 202 are set to be 1 mm or more and 3 mm or less, or 1 mm or more and 2 mm or less. In addition, the inner diameter of the second front washer 210 is larger than the inner diameter of the second front spring washer 212. Therefore, the second front spring washer 212 contacts the outer surface of the third cylindrical member 302 described later. The difference in inner diameter between the second front washer 210 and the second front spring washer 212 also depends on the wire diameter of the second coil spring 142, but the second front washer 210 and the second front spring washer 212 may be configured to be in the range of 1 mm to 5 mm or 1 mm to 3 mm, for example.

The second unit 200 is further provided with a ring-shaped first rear washer 214 for supporting one end of the first coil spring 140 on the second end side opposite to the first end of the second cylindrical member 202. The first rear washer 214 is provided so as to surround the second cylindrical member 202. The first rear washer 214 is provided so as to have a gap between the first rear washer 214 and the inner surface of the first cylindrical member 102. As an optional configuration, the second unit 200 may further include a first rear spring washer 216 that is in contact with the first rear washer 214 and is disposed on the first end side of the first rear washer 214. The first rear spring washer 216 is also provided so as to surround the second cylindrical member 202. The outer diameter of the first rear spring washer 216 is larger than the outer diameter of the first rear washer 214. Therefore, the first rear spring washer 216 contacts the inner surface of the first cylindrical member 102. The first rear washer 214 may also be integral with the second cylindrical member 202.

As with the first unit 100, the second cylindrical member 202, the second front washer 210, the second front spring washer 212, the first rear washer 214, and the first rear spring washer 216 each contain a metal material such as iron, aluminum, or stainless steel, and are preferably formed using stainless steel. The first end side and the surface of the first rear spring washer 216 on the first end side and the surface of the first cylindrical member 102 side, and the second end side and the surface of the second front spring washer 212 on the third cylindrical member 302 side may be formed with a coating layer to reduce friction with the first coil spring 140, the second coil spring 142, the first cylindrical member 102, and the third cylindrical member 302. A coating layer for reducing friction may also be formed on the outer surface of the second cylindrical member 202. On the other hand, the first end face side and the surface facing the first cylindrical member 102 of the first rear washer 214, and the second end side and the surface facing the third cylindrical member 302 of the second front washer 210 may be subjected to hot-dip galvanizing or hot-dip aluminum plating.

The bottom surface of the second end side of the second cylindrical member 202 has an opening (a dotted oval in the figure) as shown in FIG. 2. This opening may be provided with a ring-shaped flange 218 for supporting the second sliding plate 122 described below. The flange 218 may be a member independent of the second cylindrical member 202, or may be integrated with the second cylindrical member 202 or the first rear washer 214.

4. Third Unit The third unit 300 shown here is a member to which a second hook 304 used for connection to an overhead line is fixed, and has the smallest outer diameter among the multiple units. The third unit 300 has a third cylindrical member 302 as a member having a tubular or cylindrical shape, a part of which is inserted inside the second unit 200. The second hook 304 is fixed by welding or bolting to one end (first end) of the third cylindrical member 302 exposed from the second cylindrical member 202. An opening is also provided on the bottom surface of the second end side of the third cylindrical member 302 facing the first end.

As with the second unit 200, the third unit 300 is also provided with a ring-shaped second rear washer 314 for supporting one end of the second coil spring 142 on the second end side of the third cylindrical member 302. The second rear washer 314 is provided so as to surround the third cylindrical member 302. The second rear washer 314 may be integrated with the third cylindrical member 302. The second rear washer 314 is provided so as to have a gap between it and the inner surface of the second cylindrical member 202. As an optional configuration, the third unit 300 may further include a second rear spring washer 316 that is in contact with the second rear washer 314 and is disposed on the first end side of the second rear washer 314. The second rear spring washer 316 is also provided so as to surround the third cylindrical member 302. The outer diameter of the second rear spring washer 316 is larger than the outer diameter of the second rear washer 314.

As with the first unit 100 and the second unit 200, the third cylindrical member 302, the second rear washer 314, and the second rear spring washer 316 each contain a metal such as iron, aluminum, or stainless steel, and are preferably formed using stainless steel. The first end side and the surface of the second rear spring washer 316 on the second cylindrical member 202 side may be provided with the above-mentioned coating layer to reduce friction with the second coil spring 142 and the second cylindrical member 202. On the other hand, the outer surface of the third cylindrical member 302 and the first end side and the surface of the second rear washer 314 on the second cylindrical member 202 side may be hot-dip galvanized or hot-dip aluminum plated.

5. Coil Spring A first coil spring 140 and a second coil spring 142 are disposed between the first unit 100 and the second unit 200, and between the second unit 200 and the third unit 300, respectively. The first coil spring 140 and the second coil spring 142 are disposed so as to surround the second cylindrical member 202 and the third cylindrical member 302, respectively. Therefore, in the direction perpendicular to the central axis (x direction), the first coil spring 140 is sandwiched between the first cylindrical member 102 and the second cylindrical member 202, and the second coil spring 142 is sandwiched between the second cylindrical member 202 and the third cylindrical member 302. On the other hand, in the x direction, the first coil spring 140 is sandwiched between the first front spring washer 112 and the first rear washer 214, and the second coil spring 142 is sandwiched between the second front spring washer 212 and the second rear washer 314. When the first rear spring washer 216 is arranged, the first coil spring 140 is sandwiched in the x direction between the first front washer 110 and the first rear washer 214 via the first front spring washer 112 and the first rear spring washer 216. Similarly, when the second rear spring washer 316 is arranged, the second coil spring 142 is sandwiched in the x direction between the second front washer 210 and the second rear washer 314 via the second front spring washer 212 and the second rear spring washer 316.

6. Sliding Plates The tension balancer 10 further includes a plurality of first sliding plates 120 between the first unit 100 and the second unit 200, and a plurality of second sliding plates 122 between the second unit 200 and the third unit 300. The first sliding plate 120 and the second sliding plate 122 are rectangular metal plates including metals such as iron, aluminum, copper, or alloys including one or more of these metals, such as stainless steel, and are arranged in a curved state around the central axis in the tension balancer 10 (see FIG. 3). That is, the plurality of first sliding plates 120 and the plurality of second sliding plates 122 are curved to give an arc-shaped cross section in the yz plane when arranged in the tension balancer 10.

The first sliding plate 120 and the second sliding plate 122 each have a thickness that allows their ends to be inserted into the gap between the first front spring washer 112 and the first cylindrical member 102 and the gap between the second front spring washer 212 and the second cylindrical member 202. Specifically, each of the first sliding plate 120 and the second sliding plate 122 has a thickness of 0.5 mm to 3 mm, 0.5 mm to 2 mm, or 0.5 mm to 1 mm. There is no restriction on the number of the first sliding plate 120 and the second sliding plate 122, and two first sliding plates 120 and two second sliding plates 122 may be arranged as shown in FIG. 3. Alternatively, three or more first sliding plates 120 and three or more second sliding plates 122 may be arranged. Also, although not shown, the number of first sliding plates 120 and second sliding plates 122 may differ from each other.

2 and 3, each of the first sliding plates 120 is disposed between the first coil spring 140 and the first cylindrical member 102, contacts the first coil spring 140 and the first cylindrical member 102, and is provided so as to cover a part of the first coil spring 140. Preferably, the multiple first sliding plates 120 are disposed so that almost the entire first coil spring 140 is surrounded by the multiple first sliding plates 120. Similarly, each of the second sliding plates 122 is disposed between the second coil spring 142 and the second cylindrical member 202, contacts the second coil spring 142 and the second cylindrical member 202, and is provided so as to cover a part of the second coil spring 142. Preferably, the multiple second sliding plates 122 are arranged so that almost the entire second coil spring 142 is surrounded by the multiple second sliding plates 122.

Furthermore, as shown in FIG. 2, each of the multiple first sliding plates 120 is arranged such that a portion including one side is sandwiched between the first front spring washer 112 and the first cylindrical member 102, and the side opposite this side is supported by the cover body 106. Similarly, each of the multiple second sliding plates 122 is arranged such that a portion including one side is sandwiched between the second front spring washer 212 and the second cylindrical member 202. If a flange 218 is provided, the side opposite the above side is supported by the flange 218.

A coating layer for reducing friction between the first coil spring 140 and the second coil spring 142 can be formed on the surfaces of each of the first sliding plates 120 and the second sliding plates 122 that come into contact with the first coil spring 140 and the second coil spring 142, respectively. The coating layer used here may be selected from the coating layers described above.

7. Anti-Rotation Mechanism The first coil spring 140 and the second coil spring 142 are both placed in a compressed state inside the tension balancer 10. Therefore, a restoring force acts on the first coil spring 140 and the second coil spring 142 in a direction to return them to their natural lengths. In other words, a restoring force acts to stretch them in the x direction. Therefore, when no load is applied to the tension balancer 10, the tension balancer 10 contracts in the x direction so that the first front spring washer 112 and the first rear spring washer 216 move away from each other and the second front spring washer 212 and the second rear spring washer 316 move away from each other. On the other hand, when the first hook 104 is fixed to a support or the like and the second hook 304 is connected to an overhead line, the weight and contraction force of the overhead line are applied to the tension balancer 10 via the second hook 304, and the third unit 300 and the second unit 200 are pulled outward. However, because a restoring force acts on the first coil spring 140 and the second coil spring 142, a tension that pulls the overhead wire toward the inside of the tension balancer 10 can always be applied to the overhead wire. Therefore, the overhead wire can always be pulled with an appropriate tension.

In this way, inside the tension balancer 10, the first coil spring 140 and the second coil spring 142 expand and contract due to the tension they receive from the overhead line. The first coil spring 140 and the second coil spring 142 expand and contract and twist at the same time, applying a force that rotates the first sliding plate 120 and the second sliding plate 122 around their central axes. When such rotation occurs, the first sliding plates 120 or the second sliding plates 122 may interfere with each other and be damaged. Alternatively, the first sliding plates 120 or the second sliding plates 122 may overlap with each other, resulting in a misalignment of the central axes of the first cylindrical member 102, the second cylindrical member 202, and the third cylindrical member 302, and large friction occurs when the tension balancer 10 expands and contracts.

For this reason, the tension balancer 10 is provided with a rotation prevention mechanism for restricting the rotation of the first sliding plate 120 and the second sliding plate 122. This rotation prevention mechanism will be described using the schematic side views shown in Figures 4 and 5, and the schematic perspective views, side views, and front views shown in Figures 6(A) to 6(C), respectively. Figures 4 and 5 are schematic side views of the tension balancer 10 as seen from the second end side where the first hook 104 is provided, and in this figure, not only the first hook 104, reinforcing member 108, and cover body 106, but also the first coil spring 140 and second coil spring 142 have been omitted for ease of viewing.

As shown in FIG. 4, a plurality of first stoppers 130 are provided as a rotation prevention mechanism for the first sliding plate 120. More specifically, the first stoppers 130 are disposed between two adjacent first sliding plates 120. Each of the plurality of first stoppers 130 is sandwiched between two adjacent first sliding plates 120 on a circumference in which the arc formed by the end faces of the first sliding plates 120 in the yz plane is a part of the circle. In other words, the plurality of first sliding plates 120 and the plurality of first stoppers 130 alternate on this circumference. It is preferable that the plurality of first stoppers 130 are disposed so as to be equidistant from each other on the yz plane. For example, when two first stoppers 130-1 and 130-2 are provided, it is preferable that they are disposed so as to be point-symmetric with respect to the central axis Ac, as shown in FIG. 4.

Similarly, a plurality of second stoppers 132 are provided as a rotation prevention mechanism for the second sliding plate 122. More specifically, the second stoppers 132 are disposed between two adjacent second sliding plates 122. Each of the plurality of second stoppers 132 is sandwiched between two adjacent second sliding plates 122 on a circumference in which the arc formed by the end faces of the second sliding plates 122 in the yz plane is a part of the circle. In other words, the plurality of second sliding plates 122 and the plurality of second stoppers 132 alternate on this circumference. It is preferable that the plurality of second stoppers 132 are also disposed so as to be equidistant from each other on the yz plane. For example, when two second stoppers 132-1 and 132-2 are provided, it is preferable that they are disposed so as to be point-symmetrical with respect to the central axis Ac, as shown in FIG. 4.

As described above, there is no restriction on the number of first sliding plates 120 and second sliding plates 122. For example, when four first sliding plates 120 and four second sliding plates 122 are provided, as shown in FIG. 5, four first sliding plates 120 and four first stoppers 130 alternate on the above-mentioned circumference, and four second sliding plates 122 and four second stoppers 132 alternate.

The detailed structure of the first stopper 130 will be described with reference to Figs. 6(A) to 6(C). As shown in these figures, a notch 112a is provided on the outer periphery of the first front spring washer 112, and the first stopper 130 is disposed within this notch 112a. More specifically, the first stopper 130 is a protrusion protruding from the notch 112a in a direction from the center of the first front spring washer 112 toward the outer periphery (hereinafter, this direction is referred to as the radial direction). The first stopper 130 may be integrated with the first front spring washer 112, or may be fixed to the first front spring washer 112 as a separate member by welding or bolting. The height h of the first stopper 130 (length from the first front spring washer 112 in the radial direction) is greater than the depth d of the notch 112a (length in the radial direction) (see Fig. 6(B)). The first stopper 130 is configured to contact the first cylindrical member 102 (see FIGS. 4 and 5). In addition, the outer surface of the first stopper 130 (the surface opposite to the surface that contacts the first front spring washer 112) may be located on the same plane as the outer circumferential surface of the first front washer 110 (see FIGS. 6(A) and 6(B)).

As shown in FIG. 6(A) and FIG. 6(C), a portion of the first stopper 130 may overlap the first front washer 110 in a direction perpendicular to the x direction (e.g., the y direction). That is, a notch that overlaps with the notch 112a in the x direction may be provided on the outer periphery of the first front washer 110, and the first stopper 130 may be provided so that a portion of the first stopper 130 is disposed within the notch of the first front washer 110. In this case, the first stopper 130 may be integrated with the first front washer 110, or may be fixed to the first front washer 110 as a separate member by welding or bolting.

By providing the first stopper 130, even if the first sliding plate 120 rotates around the central axis (see the arrow in Figure 6 (B)), it collides with the first stopper 130 and the rotation is restricted. As a result, interference between the first sliding plates 120 is prevented, and damage or overlap caused by this can be prevented.

The configuration of the rotation prevention mechanism is not limited to the above-mentioned configuration, and any configuration can be adopted as long as it is possible to restrict the rotation of the first sliding plate 120. For example, as shown in the schematic side view and front view of Figures 7(A) and 7(B), the first front spring washer 112 may not have a notch 112a for the first stopper 130 (see Figures 6(A) to 6(C)), and the protrusion 112b protruding from the outer periphery of the first front spring washer 112 in the radial direction may be used as the rotation prevention mechanism, i.e., the first stopper 130.

Alternatively, as shown in the schematic front view of FIG. 7(D) and the schematic view of the end surface along the chain line C-C' (FIG. 7(C)), a screw 136 that penetrates the first cylindrical member 102 and overlaps with the first front spring washer 112 in a direction perpendicular to the x direction (for example, the y direction) may be used as the first stopper 130. In this case, a notch 112a may be provided in the first front spring washer 112 (see FIGS. 6(A) to 6(C)), and the screw 136 may be provided so that the tip of the screw 136 is located within the notch 112a. When using the screw 136, it is preferable to provide a notch 102a in a part of the first cylindrical member 102 and configure the first cylindrical member 102 so that the head of the screw 136 is accommodated inside the notch 102a. Although not shown, when a screw 136 that penetrates the second cylindrical member 202 is used as the second stopper 132, a notch that accommodates the head of the screw 136 can be provided in the second cylindrical member 202 to prevent interference with the first coil spring 140.

The configuration of the second stopper 132 is similar to that of the first stopper 130, so a detailed explanation will be omitted.

As described above, by providing the first stopper 130 and the second stopper 132, the rotation of the first sliding plate 120 and the second sliding plate 122 can be restricted, and interference between them can be prevented. This makes it possible to extend the life and increase the reliability of the tension balancer 10.

In addition, a coating layer is formed on the surfaces of the first sliding plate 120 and the second sliding plate 122 that come into contact with the first coil spring 140 and the second coil spring 142, respectively, so friction between the first coil spring 140 and the second coil spring 142 is small. This reduces hysteresis in the stroke-tension characteristics, and allows the stroke length to be increased within the required tension range.

In addition, the friction between the first coil spring 140 and the second coil spring 142 can be reduced and the stroke length can be increased by providing a coating layer on the inner surface of the first cylindrical member 102 or the second cylindrical member 202 without using the first sliding plate 120 or the second sliding plate 122. However, it is not necessarily easy to uniformly form such a coating layer on the inner surface of a cylindrical member, which leads to an increase in manufacturing costs. In contrast, since the first sliding plate 120 and the second sliding plate 122 are manufactured and arranged by processing a flat metal plate, the coating layer can be formed when the first sliding plate 120 and the second sliding plate 122 are in a flat state. Therefore, the coating layer can be formed on the first sliding plate 120 and the second sliding plate 122 at low cost. This contributes to reducing the manufacturing cost of the tension balancer 10.

Second Embodiment
In the first embodiment, a two-stage tension balancer 10 was mainly described, that is, a tension balancer 10 in which a second hook 304 for fixing an overhead wire to a third unit is provided, but the concept of the present invention can also be applied to a tension balancer having more stages. In this embodiment, a three-stage tension balancer 12 will be described as one embodiment of the present invention. Descriptions of configurations that are the same as or similar to those described in the first embodiment may be omitted.

A schematic end view of the tension balancer 12 is shown in FIG. 8. FIG. 8 is an end view corresponding to FIG. 2. As shown in FIG. 8, the third unit 300 has the same function as the second unit 200 of the first embodiment, and a third front washer 310 and a third front spring washer 312 are provided on one end (first end) side of the third cylindrical member 302. The configurations of the third front washer 310 and the third front spring washer 312 are similar to those of the second front washer 210 and the second front spring washer 212 of the first embodiment, respectively, and therefore will not be described.

The tension balancer 12 further has a fourth unit, a part of which is inserted into the third cylindrical member 302, and the fourth unit has a structure similar to that of the third unit of the first embodiment. That is, the fourth unit has a fourth cylindrical member 402 having an outer diameter smaller than the inner diameter of the third cylindrical member 302, and an overhead line side mounting member (third hook) 404 is directly or indirectly attached to the end (first end) side exposed from the third cylindrical member 302. A third rear washer 414 is provided on the second end side facing the first end of the fourth cylindrical member 402, and a third rear spring washer 416 may be further provided on the first end side of the third rear washer 414. The fourth cylindrical member 402, the third rear washer 414, and the third rear spring washer 416 have the same configuration as the third cylindrical member 302, the second rear washer 314, and the second rear spring washer 316 of the first embodiment, respectively, and therefore will not be described.

In addition to the first coil spring 140 and the second coil spring 142, the tension balancer 12 also includes a third coil spring 144 disposed between the third cylindrical member 302 and the fourth cylindrical member 402. A third sliding plate 124 is also disposed between the third coil spring 144 and the third cylindrical member 302. The configurations of the third coil spring 144 and the third sliding plate 124 are similar to those of the second coil spring 142 and the second sliding plate 122, respectively, and therefore will not be described here.

Although detailed explanation is omitted, the tension balancer 12 is also provided with a rotation prevention mechanism for restricting the rotation of the third sliding plate 124. In addition, a coating layer can be provided on the surface of the third sliding plate 124 that contacts the third coil spring 144. As a result, friction between the third coil spring 144 and the third sliding plate 124 is small, which reduces hysteresis in the stroke-tension characteristics and allows the stroke length to be increased within the required tension range. In addition, since a rotation prevention mechanism is provided, it is possible to prevent contact between the third sliding plates 124 and the resulting damage and overlap. This also contributes to a longer life and increased reliability of the tension balancer.

Third Embodiment
In this embodiment, a description will be given of a modified example of the first sliding plate 120 or the second sliding plate 122. Descriptions of configurations that are the same as or similar to those described in the first and second embodiments may be omitted.

In the tension balancer 10 described in the first embodiment, a plurality of first sliding plates 120 and a plurality of second sliding plates 122 are arranged. On the other hand, in the tension balancer of this embodiment, at least one of the first sliding plate 120 and the second sliding plate 122 is single. Below, an embodiment in which a single first sliding plate 120 is used is described.

As shown in FIG. 9(A), when a single first sliding plate 120 is used, the first sliding plate 120, which is originally flat, is curved and processed so that a gap 120a is formed between the opposing sides in the curved state. The first sliding plate 120 is then placed between the first cylindrical member 102 and the first coil spring 140 so that the first stopper 130 is positioned in this gap 120a.

Alternatively, as shown in FIG. 9(B), one or more through holes 120b may be provided in the first sliding plate 120 together with the gap 120a or instead of the gap 120a. The first sliding plate 120 may be disposed between the first cylindrical member 102 and the first coil spring 140 so that the first stopper 130 is disposed in the through hole 120b. In the example shown in FIG. 9(B), the through hole 120b is disposed near the gap 120a, but there is no restriction on the position of the through hole 120b. For example, the through hole 120b may be disposed so as to be point symmetric with respect to the central axis, or the through hole 120b may be disposed at a position intersecting with a plurality of straight lines extending radially from the central axis. In this case, it is preferable that the angles between two adjacent straight lines selected arbitrarily are the same or substantially the same.

Alternatively, as shown in FIG. 10, one or more notches 120c may be provided in the first sliding plate 120 together with or instead of the gap 120a. The first sliding plate 120 may be disposed between the first cylindrical member 102 and the first coil spring 140 so that the first stopper 130 is disposed in the notch 120c. The notch 120c may be disposed in the same manner as the through hole 120b.

Alternatively, as shown in Figures 11(A) and 11(B), the first sliding plate 120 may be a tube (sliding tube) that provides a closed circular end surface in the yz plane. In this case, the first sliding plate 120 is provided with one or more notches 120d or through holes 120e for positioning the first stopper 130. The notches 120d and through holes 120e may be positioned in the same manner as the through holes 120b.

The first stopper 130 described in the first embodiment can be used as a rotation prevention mechanism that restricts the rotation of the first sliding plate 120 in which the notch 120c or 120d is formed. Specifically, as shown in the schematic perspective views, end views, and front views of FIG. 12(A) to FIG. 12(C), for example, a notch 112a is provided on the outer periphery of the first front spring washer 112, and a convex portion protruding radially from the notch 112a is disposed as the first stopper 130. The first sliding plate 120 is disposed between the first cylindrical member 102 and the first coil spring 140 so that the notch 120c or 120d overlaps with the first stopper 130 in the radial direction (i.e., the direction perpendicular to the x direction). This restricts the rotation of the first sliding plate 120 around the central axis.

The second sliding plate 122 can be configured in a similar manner to the first sliding plate 120, so a detailed explanation will be omitted.

As described above, in a tension balancer according to one embodiment of the present invention, one or more sliding plates with a coating layer formed on the surface are provided between adjacent units. This not only makes it possible to provide a tension balancer at low cost, but also reduces friction between the coil spring and the cylindrical member when the tension balancer expands and contracts. As a result, hysteresis in the stroke-tension characteristics is reduced, and the stroke length can be increased within the required tension range. In addition, a rotation prevention mechanism that restricts the rotation of the sliding plate is installed, which prevents the sliding plates from being damaged or overlapping, making it possible to provide a tension balancer with a long life and high reliability.

The above-described embodiments of the present invention may be combined as appropriate to the extent that they are not mutually inconsistent. In addition, products in which a person skilled in the art appropriately adds or deletes components or modifies the design based on each embodiment are also included within the scope of the present invention as long as they incorporate the gist of the present invention.

Furthermore, even if there are other effects and advantages different from those brought about by the above-mentioned embodiments, if they are clear from the description in this specification or can be easily predicted by a person skilled in the art, they are naturally understood to be brought about by the present invention.

10: tension balancer, 12: tension balancer, 100: first unit, 102: first cylindrical member, 102a: notch, 104: first hook, 106: cover, 108: reinforcing member, 110: first front washer, 112: first front spring washer, 112a: notch, 112b: convex portion, 114: U-shaped bar, 116: collar, 120: first sliding plate, 120a: gap, 120b: through hole, 120c: notch, 120d: notch, 120e: through hole, 122: second sliding plate, 124: third sliding plate, 130: first stopper, 130-1: first stopper, 130-2: first stopper, 132: second stopper, 132-1: second stopper, 132-2: second stopper, 136: screw, 140: first coil spring, 142: second coil spring, 144: third coil spring, 200: second unit, 202: second cylindrical member, 210: second front washer, 212: second front spring washer, 214: first rear washer, 216: first rear Spring washer, 218: flange, 300: third unit, 302: third cylindrical member, 304: second hook, 310: third front washer, 312: third front spring washer, 314: second rear washer, 316: second rear spring washer, 402: fourth cylindrical member, 404: third hook, 414: third rear washer, 416: third rear spring washer

Claims (14)

a first unit including a first cylindrical member having a first end and a second end, a ring-shaped first front washer located on the first end side and surrounded by the first cylindrical member, and a ring-shaped first front spring washer in contact with the second end side of the first front washer and spaced apart from the first cylindrical member;
a second unit including a second cylindrical member inserted into the first cylindrical member, the second cylindrical member having a first end exposed from the first cylindrical member and a second end located within the first cylindrical member, and a first ring-shaped rear washer surrounding the second cylindrical member and located within the first cylindrical member;
a first coil spring located between the first unit and the second unit, surrounding the second cylindrical member, and sandwiched between the first front spring washer and the first rear washer;
a plurality of first sliding plates positioned between the first coil spring and the first cylindrical member, a portion of each of the first sliding plates being sandwiched between the first front spring washer and the first cylindrical member; and a plurality of first stoppers sandwiched between adjacent first sliding plates to restrict rotation of the plurality of first sliding plates. the first front spring washer has a plurality of notches on an outer periphery;
The tension balancer according to claim 1 , wherein the first stoppers are located within the corresponding notches. The tension balancer of claim 2, wherein the height of each of the first stoppers is greater than the depth of the corresponding notch. the first front washer has a plurality of notches that overlap with the plurality of notches of the first front spring washer in a direction parallel to a central axis of the first cylindrical member,
The tension balancer according to claim 2 , wherein a portion of each of the plurality of first stops is located within the corresponding notch of the first front washer. The tension balancer according to claim 1, wherein the first stoppers are convex portions that protrude from the outer periphery of the first front spring washer in the radial direction of the first front spring washer. The tension balancer according to claim 1, wherein the plurality of first stoppers are screws that pass through the first cylindrical member. The tension balancer according to claim 1, further comprising a hook attached to the second end side of the first cylindrical member of the first unit. a third unit including a third cylindrical member inserted into the second cylindrical member and a ring-shaped second rear washer surrounding the third cylindrical member and positioned within the second cylindrical member;
a second coil spring located between the second unit and the third unit and surrounding the third cylindrical member;
a plurality of second sliding plates positioned between the second coil spring and the second cylindrical member; and a plurality of second stoppers sandwiched between adjacent second sliding plates and restricting rotation of the plurality of second sliding plates,
The second unit further comprises:
a ring-shaped second front washer located on the first end side of the second cylindrical member and surrounded by the second cylindrical member; and a ring-shaped second front spring washer located on the second end side of the second cylindrical member with respect to the second front washer, in contact with the second front washer, and spaced apart from the second cylindrical member,
2. The tension balancer according to claim 1, wherein a portion of each of the plurality of second sliding plates is sandwiched between the second front spring washer and the second cylindrical member, and the second coil spring is sandwiched between the second front spring washer and the second rear washer. the second front spring washer has a plurality of notches on an outer periphery;
The tension balancer according to claim 8 , wherein the second stoppers are located within the corresponding cutouts. The tension balancer according to claim 9, wherein the height of the second stoppers is greater than the depth of the corresponding notches. the second front washer has a plurality of notches that overlap with the plurality of notches of the second front spring washer in a direction parallel to a central axis of the second cylindrical member,
The tension balancer according to claim 9 , wherein a portion of each of the second stops is located within a corresponding one of the notches of the second front washer. The tension balancer according to claim 8, wherein the second stoppers are protrusions that protrude from the outer periphery of the second front spring washer in the radial direction of the second front spring washer. The tension balancer according to claim 8, wherein the second stoppers are screws that pass through the second cylindrical member. The tension balancer according to claim 8 , wherein the third unit further includes a hook attached to the third cylindrical member and exposed from the second cylindrical member.

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