Helical retractable mechanism, tubular expandable body strip, and method for manufacturing tubular expandable body strip.

Abstract

To provide a spiral advance / retreat operation device which can form a cylindrical elongation / contraction body (spiral wind-type elongation / contraction shaft) into a cylindrical shape, not a polygonal shape, as a whole when the cylindrical elongation / contraction body is wound into a spiral shape.SOLUTION: A spiral advance / retreat operation device forms a cylindrical elongation / contraction body 100 by winding a first band material 110 and a second band material 120 arranged inside the first band material on top of each other in a spiral shape around a common axis CX such that the band materials are offset from each other in the axis direction. The first band material comprises a first engagement protrusion row L1 and a second engagement protrusion row L2 formed of a plurality of engagement protrusions which are arranged in a longitudinal direction and protrude toward the axial line. The second band material comprises a first engagement part row L3 and a second engagement part row L4 formed of a plurality of engagement parts which are arranged in the longitudinal direction. A portion of the first band material that is of a higher rigidity than that of a circumference is curved in a cylindrical shape corresponding to the cylindrical elongation / contraction body in advance.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a helical reciprocating actuator, a strip for a cylindrical telescopic body, and a method for manufacturing the strip for a cylindrical telescopic body.

Background Art

[0002] Patent Document 1 discloses a helical reciprocating actuator that forms a cylindrical telescopic body by spirally winding a first strip and a second strip disposed inside the first strip around a common axis in a state where they are offset from each other in the axial direction (offset by half the width) around the axis.

[0003] The first strip includes a first engaging protrusion row and a second engaging protrusion row formed by a plurality of engaging protrusions disposed in the longitudinal direction thereof and convex toward the axis. On the other hand, the second strip includes a first engaging portion row and a second engaging portion row formed by a plurality of engaging portions disposed in the longitudinal direction thereof. The engaging portion is configured such that the engaging protrusion can be engaged and disengaged with the first strip and the second strip in a state where they are spirally wound around each other. The first strip includes flat strip portions and strip portions with protrusions (engaging protrusions) alternately disposed in the longitudinal direction thereof.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the band with protrusions has higher rigidity and is less prone to deformation (less likely to become cylindrical) compared to the base first band (flat band). Therefore, when the first band, in which the flat band and the band with protrusions are arranged alternately, is wound spirally, the cylindrical telescopic body (spiral-wound telescopic shaft) will have a polygonal shape rather than a cylindrical shape as a whole. For example, when winding the first band, which is unwound from the storage section of the first band, spirally, there is a problem that the first band (the corners of the polygonal shape) may interfere with surrounding members.

[0006] The present invention was made to solve these problems and provides a spiral reciprocating mechanism, a strip material for a cylindrical expandable body, and a method for manufacturing the strip material for a cylindrical expandable body, which, when wound spirally, can form a cylindrical shape rather than a polygonal shape overall. [Means for solving the problem]

[0007] The helical retractable mechanism according to this disclosure is a helical retractable mechanism that constitutes a cylindrical expandable body by spirally overlapping and winding a first strip material and a second strip material disposed inside the first strip material around a common axis while being offset from each other in the axial direction, wherein the first strip material comprises a first row of engaging protrusions and a second row of engaging protrusions arranged in its longitudinal direction and composed of a plurality of engaging protrusions convex toward the axis, and the second strip material comprises a first row of engaging parts and a second row of engaging parts composed of a plurality of engaging parts arranged in its longitudinal direction, wherein the engaging parts are configured to engage with the engaging protrusions in a detachable manner when the first strip material and the second strip material are spirally overlapped and wound around each other, and the portion of the first strip material that is more rigid than the surrounding area is pre-curved into a cylindrical shape corresponding to the cylindrical expandable body.

[0008] With this configuration, when wound spirally, the cylindrical telescopic body (spiral-wound telescopic shaft) can be made cylindrical rather than polygonal overall.

[0009] This is because the portion of the first strip material that is more rigid than the surrounding material is pre-curved into a cylindrical shape that corresponds to a tubular expandable body.

[0010] Furthermore, in the spiral reciprocating mechanism described above, the first strip material includes flat strip portions and strip portions with engaging protrusions arranged alternately in its longitudinal direction, and the strip portions with engaging protrusions include one of the engaging protrusions constituting the first row of engaging protrusions and one of the engaging protrusions constituting the second row of engaging protrusions, and the portion of the first strip material that has higher rigidity than the surrounding area may be the strip portions with engaging protrusions.

[0011] Furthermore, in the spiral reciprocating mechanism described above, the belt portion with the engaging projection may be inclined at a predetermined angle with respect to the short-side direction of the first belt material.

[0012] Furthermore, in the spiral reciprocating operating device described above, the portion of the first strip material that has higher rigidity than the surrounding area may be a first portion of the strip portion with engaging protrusions that includes one of the engaging protrusions constituting the first row of engaging protrusions, and a second portion that includes one of the engaging protrusions constituting the second row of engaging protrusions.

[0013] Furthermore, in the above-described spiral reciprocating mechanism, the radius of the cylindrical shape may be greater than or equal to the radius of the cylindrical expandable body.

[0014] Furthermore, in the spiral reciprocating mechanism described above, the radius of the cylindrical shape may increase as it moves away from the engaging projection in the longitudinal direction of the first strip material.

[0015] Furthermore, in the spiral reciprocating mechanism described above, the engaging projection may be a hollow projection integrally formed on the first strip material.

[0016] Furthermore, in the above-described spiral reciprocating mechanism, the hollow projection may be a hollow frustoconical projection.

[0017] The tubular expandable body strip material according to this disclosure is a strip material used as the first or second strip material of a spiral reciprocating device that constitutes a tubular expandable body by spirally overlapping and winding a first strip material and a second strip material disposed inside the first strip material around a common axis, with the strip material comprising a first row of protrusions and a second row of protrusions arranged in the longitudinal direction of the strip material and consisting of a plurality of protrusions convex toward the axis, and the portion of the strip material that has higher rigidity than the surrounding area is pre-curved into a cylindrical shape corresponding to the tubular expandable body.

[0018] With this configuration, when wound spirally, the cylindrical telescopic body (spiral-wound telescopic shaft) can be made cylindrical rather than polygonal overall.

[0019] This is because the portion of the strip material (either the first or second strip material) that has higher rigidity than its surroundings is pre-curved into a cylindrical shape that corresponds to a tubular expandable body.

[0020] The method for manufacturing a tubular expandable body strip according to the present disclosure is a method for manufacturing a tubular expandable body strip, wherein the protrusion and the cylindrical shape are formed simultaneously by press molding the strip using a first mold including a first convex portion corresponding to the protrusion and a second convex portion corresponding to the cylindrical shape, and a second mold including a first concave portion corresponding to the first convex portion and a second concave portion corresponding to the second convex portion.

[0021] This configuration allows for the simultaneous formation of protrusions and cylindrical shapes on the strip material.

[0022] This is achieved by press forming a strip material using a first mold including a first convex portion corresponding to a protrusion and a second convex portion corresponding to a cylindrical shape, and a second mold including a first concave portion corresponding to the first convex portion and a second concave portion corresponding to the second convex portion. [Effects of the Invention]

[0023] According to the present invention, there can be provided a helical reciprocating actuator, a strip material for a cylindrical expandable body, and a method for manufacturing the strip material for a cylindrical expandable body, which can make the cylindrical expandable body (helical winding type expandable shaft) have a cylindrical shape as a whole instead of a polygonal shape when helically wound.

Brief Description of the Drawings

[0024] [Figure 1] An explanatory diagram showing the configuration of an expansion device provided with a helical winding type expandable shaft. [Figure 2] An explanatory diagram showing how to form a helical winding type expandable shaft. [Figure 3] A cross-sectional view of the helical winding type expandable shaft in the first reference example. [Figure 4] A cross-sectional view of the helical winding type expandable shaft in the comparative example. [Figure 5] An explanatory diagram showing the press forming method of the first strip member in the first reference example. [Figure 6] An explanatory diagram showing the press forming method of the first strip member in the second reference example. [Figure 7] An explanatory diagram showing the press forming method of the first strip member in the third reference example. [Figure 8] A cross-sectional view of the helical winding type expandable shaft in the fourth reference example. [Figure 9] A cross-sectional view of the helical winding type expandable shaft in the fifth reference example. [Figure 10] (a) A plan view of the first strip member 110, (b) A cross-sectional view taken along the line A-A of FIG. 10(a), (c) A diagram for explaining that when the first strip member 110 in FIG. 10(a) is helically wound, the helical winding type expandable shaft 100 becomes polygonal as a whole. [Figure 11] (a) A perspective view of the first strip member 110, (b) A cross-sectional view taken along the line B-B of FIG. 11(a), (c) A diagram for explaining that when the first strip member 110 in FIG. 11(a) is helically wound, the helical winding type expandable shaft 100 becomes cylindrical as a whole. [Figure 12] (a) A diagram showing the first strip member 110 before press forming, (b) A diagram showing the first strip member 110 after press forming. [Figure 13] This is a flowchart of the cylindrical shape forming method (press forming method). [Figure 14] A diagram showing a modified example of the first strip-shaped member 110. [Figure 15] A diagram showing the first strip-shaped member 110 in another modified example. [Modes for carrying out the invention]

[0025] <1st reference example> The extension / retraction device 60 (spiral-shaped reciprocating device) of the first reference example will be described with reference to Figures 1 to 9.

[0026] Figure 1 is an explanatory diagram showing the configuration of an extension device 60 equipped with a spiral-wound extension shaft. The extension device 60 of this first reference example has a spiral-wound extension shaft 100 formed by spirally winding two strip-shaped members 110 and 120, a first housing section 10 for housing the first strip-shaped member 110, a second housing section 20 for housing the second strip-shaped member 120, a guide section 30 that guides the two strip-shaped members 110 and 120 and winds them spirally, a drive section 40 that rotates the guide member 32 of the guide section 30, and a cap section 50 attached to the tip of the spiral-wound extension shaft 100. When the drive section 40 drives the guide member 32 to rotate in one direction, the two strip-shaped members 110 and 120 are guided by the guide member 32 and wound spirally, and the spiral-wound extension shaft 100 extends upward in Figure 1. When the guide member 32 rotates in the opposite direction, the winding of the two strip-shaped members 110 and 120 is released, and they are housed in their respective storage sections 10 and 20, shortening the spiral-wound telescopic shaft 100. Alternatively, instead of rotating the guide member 32, the spiral-wound telescopic shaft 100 itself may be rotated to perform the extension and retraction. The strip-shaped members 110 and 120 can be made of metal (for example, a springy metal such as stainless steel for springs). The strip-shaped members 110 and 120 may also be made of other materials such as deformable resin.

[0027] Figure 2 is an explanatory diagram showing how a spiral-wound telescopic shaft 100 is formed by winding two strip-shaped members 110 and 120 together. In Figure 2, for ease of illustration, the outer shape of the second strip-shaped member 120 is drawn with a dashed line. The upper left of Figure 2 shows the state before winding, and the upper right shows the overlapping arrangement of the two strip-shaped members 110 and 120 in the wound state, unfolded on a plane.

[0028] The spiral-wound telescopic shaft 100 is formed by spirally winding a first strip-shaped member 110 and a second strip-shaped member 120, which is positioned inside the first strip-shaped member 110, around an axis CX. The first strip-shaped member 110 has a first flat strip portion 111 and a plurality of first engaging portions 112 arranged in multiple rows along the longitudinal direction of the first strip-shaped member 110. The first flat strip portion 111 is a flat, strip-shaped portion without protrusions or recesses. The first engaging portions 112 are arranged in two rows at regular intervals along the longitudinal direction of the first strip-shaped member 110. The second strip-shaped member 120 has a second flat strip portion 121 and a plurality of second engaging portions 122 arranged in multiple rows along the longitudinal direction of the second strip-shaped member 120. The second flat strip portion 121 is a flat, strip-shaped portion without protrusions or recesses. The second engaging portion 122 is arranged in two rows at regular intervals along the longitudinal direction of the second strip-shaped member 120.

[0029] In the spiral-wound telescopic shaft 100 shown in the lower part of Figure 2, the first strip-shaped member 110 is wound at a constant pitch Pt along the axis CX. The distance Le between the two rows of first engaging portions 112 along the direction of axis CX is equal to half the winding pitch Pt. The second strip-shaped member 120 has a similar configuration.

[0030] The first strip-shaped member 110 has a width W1, and the second strip-shaped member 120 has a width W2. These widths W1 and W2 are approximately equal and set to a value slightly smaller than the winding pitch Pt. The two strip-shaped members 110 and 120 are overlapped and wound spirally, offset from each other by half the winding pitch Pt. As a result, the two rows of first engaging portions 112 of the first strip-shaped member 110 engage with the second engaging portions 122 of the two second strip-shaped members 120 that are overlapped inside the first strip-shaped member 110.

[0031] Figure 3 is a cross-sectional view of the spiral winding type telescopic shaft 100 in the first reference example. The first engaging portion 112 of the first strip-shaped member 110 is configured as a first hollow projection 114 that protrudes toward the axis CX. The first engaging portion 112 also has an opening 116 in the center.

[0032] The second engaging portion 122 of the second strip-shaped member 120 is configured to engage with the first engaging portion 112 of the first strip-shaped member 110. In the first reference example, the second engaging portion 122 is also configured as a second hollow projection 124 that protrudes toward the axis CX, similar to the first engaging portion 112, and has an opening 126 in its center. The second engaging portion 122 may be configured to have substantially the same shape as the first engaging portion 112, and it is preferable that the shape of the protrusion be slightly larger than that of the first engaging portion 112.

[0033] The inner surface of the first hollow projection 114 and the outer surface of the second hollow projection 124 are configured to be in surface contact with each other. In this configuration, the contact pressure can be reduced compared to when the two engaging parts are in point contact. As a result, deformation due to contact can be reduced, and noise and vibration can also be reduced.

[0034] The first hollow projection 114 preferably extends in a direction inclined from the first flat band 111. Similarly, the second hollow projection 124 preferably extends in a direction inclined from the second flat band 121. This ensures that the first hollow projection 114 and the second hollow projection 124 are in reliable surface contact while being smoothly engaged. The angle θ between the first hollow projection 114 and the first flat band 111 is preferably set in the range of 30 to 85 degrees. The same applies to the second hollow projection 124. Generally, the larger the angle θ, the higher the engagement and holding force, but if the angle θ is too large, resistance may occur when winding or releasing. Setting the angle θ in the range of 30 to 85 degrees prevents excessive resistance from occurring when winding or releasing while maintaining a high engagement and holding force.

[0035] The first engaging portion 112 protrudes inward from the inner surface 111i of the first flat band portion 111. On the other hand, there is no portion that protrudes outward from the outer surface 111o of the first flat band portion 111. These configurations are the same for the second band-shaped member 120. In this disclosure, "inside" means the inside of the helical winding type telescopic shaft 100, i.e., the side of axis CX, and "outside" means the outside of the helical winding type telescopic shaft 100.

[0036] Figure 4 is a cross-sectional view of a spiral-wound telescopic shaft in a comparative example. In this comparative example, the first strip-shaped member 11 has a first flat strip portion 12 and a solid engaging pin 14. The engaging pin 14 is joined to the first flat strip portion 12 by welding, and a weld mark 16 is formed that protrudes to the outside of the first flat strip portion 12. The second strip-shaped member 21 has a second flat strip portion 22 and an engaging hole 24.

[0037] In this comparative example, the spiral-wound telescopic shaft requires numerous engagement pins 14 to be joined to the first flat strip portion 12, which increases the weight and cost of the first strip-shaped member 11. Furthermore, when the spiral-wound telescopic shaft is repeatedly extended and retracted, fatigue failure may occur at the joints of the engagement pins 14. In addition, because the first strip-shaped member 11 has portions that protrude outward from its outer surface, interference and resistance increase when it is guided by the guide portion 30.

[0038] On the other hand, in the spiral winding type telescopic shaft 100 of the first reference example shown in Figure 3, the first engaging portion 112 of the first strip-shaped member 110 is configured as a hollow projection, so a lighter and lower-cost spiral winding type telescopic shaft can be provided compared to using a solid engaging pin. Also, since the first hollow projection 114 of the first strip-shaped member 110 and the second hollow projection 124 of the second strip-shaped member 120 are in surface contact, the contact pressure can be reduced compared to when the two engaging portions are in point contact. As a result, deformation due to contact can be reduced, and noise and vibration can be reduced. Furthermore, since the first strip-shaped member 110 does not have a portion that protrudes outward from the outer surface 111o of the first flat strip portion 111, interference and resistance when guided by the guide portion 30 are reduced, and the spiral winding type telescopic shaft 100 can be extended and shortened smoothly.

[0039] Figure 5 is an explanatory diagram showing the press forming method of the first strip-shaped member 110 of the first reference example. The upper part of Figure 5 shows the state before press forming, and the center shows the state after press forming. The lower part of Figure 5 shows a perspective view of the first engaging portion 112 of the first strip-shaped member 110.

[0040] Before press forming, a plurality of holes 118 are formed in the first flat strip portion 111. A die 70 and a punch 71 are used for press forming. The die 70 is positioned around the holes 118. During press forming, the punch 71 advances toward the holes 118, forming a first engaging portion 112 having a first hollow projection 114 and an opening 116. In this way, the first hollow projection 114 can be configured as a press-formed portion that protrudes inward from the first flat strip portion 111. The second engaging portion 122 of the second strip member 120 can also be formed similarly by press forming. By using press forming, the first hollow projection 114 and the second hollow projection 124 can be easily formed.

[0041] As can be seen from Figure 5, the first engaging portion 112 of the first reference example has a perforated frustoconical shape. The second engaging portion 122 is similar. If the first engaging portion 112 is formed by press molding, the angle of the first hollow projection 114 can be set to a large value. As explained in Figure 3, it is preferable to set the angle θ between the first hollow projection 114 and the first flat band portion 111 in the range of 30 to 85 degrees. Furthermore, it is preferable that the boundary portion between the first hollow projection 114 and the first flat band portion 111 has a gently changing shape such as an R shape, rather than an acute angle. This prevents stress concentration from occurring at the boundary portion between the first hollow projection 114 and the first flat band portion 111.

[0042] As described above, in the first reference example, the first engaging portion 112 of the first strip-shaped member 110 is configured as the first hollow projection 114, so a lightweight and low-cost telescopic shaft can be provided compared to using a solid engaging pin. Furthermore, since the first hollow projection 114 and the second hollow projection 124 are configured to make surface contact, the contact pressure can be reduced compared to when the two engaging portions make point contact. As a result, deformation due to contact can be reduced, and noise and vibration can also be reduced. <Second reference example> Figure 6 is an explanatory diagram showing the press forming method of the first strip-shaped member 210 of the second reference example. As shown in the lower part of Figure 6, the first strip-shaped member 210 of the second reference example has a first flat strip portion 211 and a first engaging portion 212, the first engaging portion 212 having a first hollow projection portion 214 and a top portion 216. There is no opening in the top portion 216. In the example of Figure 6, the top portion 216 is almost flat. That is, the first engaging portion 212 is formed to have a frustoconical shape with the top portion 216 closed. The top portion 216 may be flat or may have a dome shape.

[0043] Before press forming, no holes are formed in the first flat strip portion 211. A die 70 and a punch 72 are used for press forming. The die 70 is positioned around the formation location of the first engagement portion 212. The punch 72 has a frustoconical shape that conforms to the shape of the first engagement portion 212. During press forming, the punch 72 advances to the formation location of the first engagement portion 212, thereby forming the first engagement portion 212 having a first hollow projection 214 and a apex 216. That is, the first engagement portion 212 is press-formed. In this way, the first hollow projection 214 of the second reference example can also be configured as a press-formed portion protruding from the first flat strip portion 211. Similarly, the second engagement portion of the second strip-shaped member can also be formed into a frustoconical shape with a closed apex by press forming.

[0044] In the second reference example, there is no need to form an opening in the first strip-shaped member 210, so the manufacturing process can be simplified compared to the first reference example. However, the first reference example has the advantage that the first strip-shaped member 110 can be made lighter because it has an opening 116. Also, the first reference example has the advantage that it is easier to set the angle θ of the first hollow projection 114 to a larger value. These advantages are also true for the second strip-shaped member. <3rd reference example> Figure 7 is an explanatory diagram showing a press forming method for the first strip-shaped member 310 of the third reference example. As shown in the lower part of Figure 7, the first strip-shaped member 310 of the third reference example has a first flat strip portion 311 and a first engaging portion 312. The first engaging portion 312 has a first hollow projection portion 314 and a top portion 316, and has a trapezoidal bridge shape. The first hollow projection portion 314 is formed as the left and right legs of the trapezoid, and the top portion 316 is configured as the upper base of the trapezoid. Notches 318 are formed on both sides of the trapezoidal bridge-shaped first engaging portion 312. The notches 318 are the parts where the first flat strip portion 311 and the first engaging portion 312 are separated. The notches 318 on both sides of the first engaging portion 312 communicate with the inside of the first engaging portion 312.

[0045] The top 316 of the first engaging portion 312 has no opening and is almost flat. The first hollow projections 314 on both sides of the top 316 are also almost flat. The direction D1 in which the two first hollow projections 314 and the top 316 are aligned is preferably an oblique direction with an appropriate angle of less than 90 degrees with respect to the longitudinal direction of the first strip-shaped member 310. This is because if direction D1 is aligned parallel to the longitudinal direction of the first strip-shaped member 310, it will be easy to wrap but may be somewhat prone to loosening, while if it is aligned perpendicularly, the holding force will be high but it may be difficult to wrap. In other words, if direction D1 is inclined with respect to the longitudinal direction of the first strip-shaped member 310, it can be made easy to wrap and less prone to loosening.

[0046] Before press forming, no holes are formed in the first flat strip portion 311, but as shown in the center of Figure 7, notches 318 are formed on both sides of the formation position of the first engaging portion 312. A die 70 and a punch 73 are used for press forming. The die 70 is positioned around the formation position of the first engaging portion 312. The punch 73 has a rectangular prism shape that conforms to the shape of the first engaging portion 312. During press forming, the punch 73 advances to the formation position of the first engaging portion 312, thereby forming the first engaging portion 312 having a first hollow projection 314 and a top portion 316. In this way, the first hollow projection 314 of the third reference example can also be configured as a press-formed portion protruding from the first flat strip portion 311. Similarly, the second engaging portion of the second strip-shaped member can be formed into a trapezoidal bridge shape by press forming.

[0047] In the third reference example, since there is no need to form an opening, the manufacturing process can be simplified compared to the first reference example. In addition, in the third reference example, engagement can be performed smoothly while bearing the force on both sides of the first engaging portion 312 in which the notch 318 is formed. In particular, if the first engaging portion of the first strip member and the second engaging portion of the second strip member are each formed in a trapezoidal bridge shape, the first engaging portion and the second engaging portion can be engaged smoothly. <4th reference example> Figure 8 is a cross-sectional view of the spiral-wound telescopic shaft 400 in the fourth reference example. The spiral-wound telescopic shaft 400 is formed by spirally winding a first strip-shaped member 410 and a second strip-shaped member 420. The first strip-shaped member 410 has a shape similar to the first strip-shaped member 110 in the first reference example shown in Figure 3. That is, the first strip-shaped member 410 has a first flat strip portion 411 and a plurality of first engaging portions 412, and the first engaging portions 412 include a first hollow projection portion 414 and an opening 416.

[0048] The second strip-shaped member 420 of the fourth reference example has a second flat strip portion 421 and a plurality of second engaging portions 422. The second engaging portions 422 are formed as engaging holes. In this fourth reference example, the second engaging portions 422 are configured to fit with the first hollow projection 414 of the first engaging portion 412, similar to the first to third reference examples described above.

[0049] In the fourth reference example, the spiral-wound telescopic shaft 400 also has the first engaging portion 412 of the first strip-shaped member 410 configured as the first hollow projection 414, thus providing a lighter and lower-cost telescopic shaft compared to using a solid engaging pin. However, in the fourth reference example, the peripheral edge of the second engaging portion 422 of the second strip-shaped member 420 engages with the first engaging portion 412 of the first strip-shaped member 410 by point contact. On the other hand, in the first to third reference examples described above, the first engaging portion and the second engaging portion make surface contact, which has the advantage of being less prone to vibrations and noise caused by point contact. <5th reference example> Figure 9 is a cross-sectional view of the spiral-wound telescopic shaft 500 in the fifth reference example. The spiral-wound telescopic shaft 500 is formed by spirally winding a first strip-shaped member 510 and a second strip-shaped member 520. The first strip-shaped member 510 has a shape similar to the first strip-shaped member 110 in the first reference example shown in Figure 3. That is, the first strip-shaped member 510 has a first flat strip portion 511 and a plurality of first engaging portions 512, and the first engaging portions 512 include a first hollow projection portion 514 and an opening 516.

[0050] The second strip-shaped member 520 of the fifth reference example has a second flat strip portion 521 and a plurality of second engaging portions 522. The second engaging portions 522 are formed as engaging holes. The only difference from the fourth reference example shown in Figure 8 is that the peripheral edge portion 524 of the hole of the second engaging portion 522 that contacts the first engaging portion 512 is chamfered. Instead of chamfering, R-processing may be applied. In this way, the contact area between the first engaging portion 512 and the second engaging portion 522 can be increased compared to the fourth reference example, making it less likely for vibrations and noise caused by point contact to occur.

[0051] <Embodiment> First, we will explain the problems that the inventors have identified with the telescopic device 60 (helical reciprocating device) of the above reference example.

[0052] As described above, in the first reference example, the telescopic device 60 (helical reciprocating operating device) is configured as a helical-wound telescopic shaft 100 (an example of a cylindrical telescopic body in this disclosure) by spirally overlapping and winding a first strip-shaped member 110 (an example of a first strip material in this disclosure) and a second strip-shaped member 120 (an example of a second strip material in this disclosure) which is arranged inside the first strip-shaped member 110, with the strips offset from each other in the direction of the axis CX around a common axis CX (offset by half a width).

[0053] For example, the first strip-shaped member 110 of the first reference example above includes a first row of engaging protrusions L1 and a second row of engaging protrusions L2 (see Figure 2), which are arranged in the longitudinal direction and consist of a plurality of first hollow protrusions 114 (see Figure 3; an example of an engaging protrusion in this disclosure; hereinafter also referred to as engaging protrusion 114) that are convex toward the axis CX.

[0054] On the other hand, the second strip-shaped member 120 of the first reference example above is provided with a first engagement portion row L3 and a second engagement portion row L4 (see Figure 2), which are composed of a plurality of second engagement portions 122 (an example of an engagement portion of this disclosure) arranged in the longitudinal direction thereof.

[0055] The second engaging portion 122 is configured as a second hollow projection 124 that is convex toward the axis CX, so that the first hollow projection 114 can engage with the first strip-shaped member 110 and the second strip-shaped member 120 when they are spirally overlapped and wrapped around each other (see Figure 3).

[0056] As described above, when using a strip-shaped member having a hollow projection, that is, a first strip-shaped member 110 having a first hollow projection 114 (see Figure 3) of the first reference example, or a second strip-shaped member 120 having a second hollow projection 124 (see Figure 3) of the first reference example, the following problems arise. The same applies when using a first strip-shaped member 210 having a first hollow projection 214 (see Figure 6) of the second reference example, a first strip-shaped member 410 having a first hollow projection 414 (see Figure 8) of the fourth reference example, or a first strip-shaped member 510 having a first hollow projection 514 (see Figure 9) of the fifth reference example.

[0057] The following explanation of this issue will be given using the first strip-shaped member 110 having the first hollow projection 114 (see Figure 3) of the first reference example as an example.

[0058] Figure 10(a) is a plan view of the first strip-shaped member 110. Figure 10(b) is a cross-sectional view AA of Figure 10(a). In Figure 10(b), the dotted line represents the first strip-shaped member 110 before it is spirally wound. On the other hand, in Figure 10(b), the solid line represents the first strip-shaped member 110 after it has been spirally wound. Also, the reference numeral L5 in Figure 10(b) represents the area in the first strip-shaped member 110 that hardly deforms when it is spirally wound, that is, the part of the first strip-shaped member 110 that has higher rigidity than the surrounding area. Hereafter, this part with higher rigidity than the surrounding area will be called the protruding strip portion 113. Figure 10(c) is a diagram to explain that when the first strip-shaped member 110 of Figure 10(a) is spirally wound, the spiral-wound telescopic shaft 100 as a whole takes on a polygonal shape.

[0059] As shown in Figure 10(a), the first strip-shaped member 110 includes first flat strip portions 111 and strip portions 113 with protrusions, which are alternately arranged in the longitudinal direction.

[0060] The band portion with protrusions 113 includes one engaging protrusion 114 that constitutes the first engaging protrusion row L1 and one engaging protrusion 114 that constitutes the second engaging protrusion row L2. Therefore, it has higher rigidity and is less prone to deformation (less likely to become cylindrical) compared to the surrounding area (first flat band portion 111). Consequently, when the first band-shaped member 110, in which the first flat band portion 111 and the band portion with protrusions 113 are arranged alternately, is wound spirally, the spiral-wound telescopic shaft 100 takes on a polygonal shape as a whole, as shown in Figure 10(c).

[0061] Ideally, the first strip-shaped member 110 and the second strip-shaped member 120 should form a double cylinder with a constant and appropriate clearance between them. However, when the first strip-shaped member 110 deforms as described above and takes on a polygonal shape, the clearance between them varies from part to part. As a result, there is a problem in that the desired shaft shape cannot be maintained.

[0062] Furthermore, when constructing a spiral-wound telescopic shaft 100 with a predetermined outer diameter by spirally overlapping and winding the first strip-shaped member 110 and the second strip-shaped member 120, the first strip-shaped member 110, which is the storage part for the first strip-shaped member 110, and the second strip-shaped member 120, which is the storage part for the second strip-shaped member 120, are wound around the first hollow projection 114 and the second engagement part 122 through the guide part 30.

[0063] However, when the first strip-shaped member 110 deforms as described above and takes on a polygonal shape, there is a problem that the first strip-shaped member 110 (the corners of the polygonal shape) may interfere with the guide portion 30 when passing through it, causing noise and wear.

[0064] Next, as an embodiment, we will describe a configuration example for solving the above problem, namely, a configuration example for making the spiral-wound telescopic shaft 100 cylindrical rather than polygonal overall, as shown in Figure 11(c), when a first strip-shaped member 110, in which the first flat strip portion 111 and the strip portion 113 with protrusions are arranged alternately, is wound spirally. This configuration example can be applied not only to the first strip-shaped member 110 having the first hollow projection portion 114 (see Figure 3) of the first reference example, but also to the second strip-shaped member 120 having the second hollow projection portion 124 (see Figure 3) of the first reference example, the first strip-shaped member 210 having the first hollow projection portion 214 (see Figure 6) of the second reference example, the first strip-shaped member 410 having the first hollow projection portion 414 (see Figure 8) of the fourth reference example, and the first strip-shaped member 510 having the first hollow projection portion 514 (see Figure 9) of the fifth reference example. Furthermore, this configuration example can also be applied to the comparative example described above.

[0065] In other words, this configuration example can be applied to a strip-shaped member (strip material) used as the first strip-shaped member 110 (first strip material) or the second strip-shaped member 120 (second strip material) of an expandable / contractable device 60 (helical reciprocating operating device), which includes a portion (for example, a strip portion with a projection 113) that is more rigid than the surrounding area (for example, a first flat strip portion 111).

[0066] Below, we will describe an example in which this configuration is applied to the first strip-shaped member 110 of the first reference example.

[0067] Figure 11(a) is a perspective view of the first strip-shaped member 110. Figure 11(b) is a cross-sectional view of BB in Figure 11(a). In Figure 11(b), the dotted line represents the first strip-shaped member 110 before it is wound spirally. On the other hand, in Figure 11(b), the solid line represents the first strip-shaped member 110 after it has been wound spirally. Also, the reference numeral L6 in Figure 11(b) corresponds to the reference numeral L5 in Figure 10(b), and represents the range in which the material is pre-formed into a cylindrical shape corresponding to the spiral-wound telescopic shaft 100 (an example of a cylindrical telescopic body in this disclosure), as described later. Note that in Figure 11(a), the portion of the first strip-shaped member 110 between lines L7 and L8, which are inclined at a winding lead angle θ with respect to the shorter direction, is the strip portion with projections 113. Figure 11(c) is a diagram illustrating that when the first strip-shaped member 110 in Figure 11(a) is wound spirally, the spiral-wound telescopic shaft 100 becomes cylindrical overall.

[0068] In this embodiment, the portion of the first strip-shaped member 110 that has higher rigidity than the surrounding area (for example, the flat strip portion 111), i.e., the strip portion with projections 113, is pre-curved into a cylindrical shape corresponding to the spiral winding type telescopic shaft 100.

[0069] The central axis AX of this cylindrical shape extends in a direction inclined by a winding lead angle θ with respect to the short direction of the first strip-shaped member 110 (see Figures 11(a) and 11(b)). However, this is not limited to this, and the central axis AX of this cylindrical shape may extend in a direction other than the direction inclined by a winding lead angle θ with respect to the short direction of the first strip-shaped member 110 (for example, in the short direction of the first strip-shaped member 110).

[0070] Furthermore, the radius of this cylindrical shape is greater than or equal to the radius R of the spiral-wound telescopic shaft 100. However, the radius of this cylindrical shape may increase as it moves away from the first hollow projection 114 (an example of an engaging projection in this disclosure) in the longitudinal direction of the first strip-shaped member 110.

[0071] In Figure 11(a), the symbol W represents the cylindrical width (cylindrical surface width). The symbol D represents the base diameter of the first hollow projection 114. It is desirable to adjust the cylindrical width (cylindrical surface width) W within the range of the base diameter D of the first hollow projection 114 × 1.0 to 2.0. If it is too small, the cylindrical accuracy will be insufficient, and if it is too large, the load during molding will increase, so it is desirable to select an appropriate dimension.

[0072] In Figure 11(a), the symbol θ represents the angle of flat ground and the winding lead angle. Also in Figure 11(a), the symbol R represents the radius of the cylindrical shape (cylindrical surface). It is desirable to use an appropriate press die R for the radius R, taking into account the springback during press forming described later. For example, when constructing a spiral winding type telescopic shaft 100 with a radius of 100 mm, it is desirable to use an upper die 600 and lower dies 601, 602 that are designed so that the radius after springback is 100 mm.

[0073] As described above, by pre-curving the protruding band portion 113, which has higher rigidity than the surrounding area, into a cylindrical shape corresponding to the spiral winding type telescopic shaft 100, when the first band-shaped member 110, in which the first flat band portion 111 and the protruding band portion 113 are arranged alternately, is wound spirally, the spiral winding type telescopic shaft 100 can be made cylindrical as a whole, rather than polygonal, as shown in Figure 11(c).

[0074] As a result, the above problems can be solved. Specifically, a double-cylindrical spiral-wound telescopic shaft 100 can be constructed in which the clearance between the first strip-shaped member 110 and the second strip-shaped member 120 does not fluctuate from part to part, and a constant and appropriate clearance is maintained between the first strip-shaped member 110 and the second strip-shaped member 120. As a result, a spiral-wound telescopic shaft 100 that can maintain a desired shaft shape can be constructed.

[0075] Furthermore, because the protruding band portion 113, which has higher rigidity than its surroundings, is pre-curved into a cylindrical shape corresponding to the spiral winding type telescopic shaft 100, when the first band-shaped member 110 is unwound from the first storage portion 10, which is the storage portion of the first band-shaped member 110, and wound around the first hollow protrusion portion 114 and the second engaging portion 122 through the guide portion 30, it is possible to suppress interference between the first band-shaped member 110 (the corners of the polygonal shape) and the guide portion 30, etc., which would cause noise and wear.

[0076] Furthermore, according to the cylindrical shape forming method (press forming method) shown in Figures 12(a) and 12(b), the first hollow projection 114 and the pre-curved cylindrical band portion 113 corresponding to the spiral winding type telescopic shaft 100 can be formed simultaneously. This makes it possible to reduce costs and improve productivity without increasing the number of processes.

[0077] The ability to simultaneously form the first hollow projection 114 and the projection-equipped band portion 113, which is pre-curved into a cylindrical shape corresponding to the spiral winding telescopic shaft 100, is achieved by using an upper mold 600 (an example of the first mold in this disclosure) including a first convex portion 600a corresponding to the first hollow projection 114 (an example of the projection in this disclosure) and second convex portions 600b and 600c corresponding to the cylindrical shape, as shown in Figure 12(a), and lower molds 601 and 602 (an example of the second mold in this disclosure) including first concave portions 601a and 602a corresponding to the first convex portion 600a and second concave portions 601b and 602b corresponding to the second convex portions 600b and 600c, and performing the cylindrical shape forming method (press forming method) described later.

[0078] Next, a cylindrical shaping method (press molding method) will be described for pre-curving the portion of the first strip-shaped member 110 that has higher rigidity than the surrounding area (for example, the flat strip portion 111), i.e., the strip portion with protrusions 113, into a cylindrical shape corresponding to the spiral winding type telescopic shaft 100.

[0079] Figure 12(a) shows the first strip-shaped member 110 before press forming, and Figure 12(b) shows the first strip-shaped member 110 after press forming.

[0080] Figure 13 is a flowchart of the cylindrical shape forming method (press forming method).

[0081] First, as shown in Figure 12(a), the first strip-shaped member 110, which has a hole 118 (through hole) formed therein, is set in the lower dies 601 and 602 (step S10). Next, as shown in Figure 12(b), press forming using the upper die 600 and the lower dies 601 and 602 (step S11) is performed to pre-curve the portion of the first strip-shaped member 110 that is more rigid than the surrounding area (for example, the flat strip portion 111), i.e., the strip portion with protrusions 113, into a cylindrical shape corresponding to the spiral winding type telescopic shaft 100. Next, the first strip-shaped member 110 is fed longitudinally by 1 pitch p (see Figure 11(a)) (step S12). The above steps S11 to S12 are repeated until the press forming completion conditions are met (step S13: YES) (step S13: NO), and when the press forming completion conditions are met (step S13: YES), the process is terminated. The condition for completing press forming is, for example, that a predetermined number of presses have been performed.

[0082] As described above, according to this embodiment, when wound spirally, the spiral-wound telescopic shaft 100 (cylindrical telescopic body) can be cylindrical in shape rather than polygonal overall.

[0083] This is because a portion of the strip material (for example, the first strip-shaped member 110) that has higher rigidity than the surrounding area (for example, the strip portion with protrusions 113) is pre-curved into a cylindrical shape corresponding to the spiral winding type telescopic shaft 100 (tubular telescopic body).

[0084] Next, I will explain some variations.

[0085] Figure 14 is a diagram showing a modified example of the first strip-shaped member 110.

[0086] In the above embodiment, an example was described in which the portion of the first strip-shaped member 110 between lines L7 and L8 that are inclined at a winding lead angle θ with respect to the shorter direction is the strip portion with projections 113 (see Figure 11(a)), but the invention is not limited to this. For example, as shown in Figure 14, the strip portion with projections 113 may be the portion of the first strip-shaped member 110 between lines L9 and L10 that extend in the shorter direction.

[0087] This method also achieves the same effects as the above embodiment.

[0088] Furthermore, in the above embodiment, an example was described in which the portion that is pre-curved into a cylindrical shape corresponding to the spiral winding type telescopic shaft 100 is the entire area of ​​the projection-equipped band portion 113 (the entire area in the width direction (short direction) of the first band-shaped member 110) (see Figure 11(a)), but the invention is not limited to this.

[0089] Figure 15 shows a first strip-shaped member 110 of another modified example.

[0090] As shown in Figure 15, the portion of the spiral winding telescopic shaft 100 that is pre-curved into a cylindrical shape may be a part 113a, 113b of the projection-equipped band 113. A part 113a of the projection-equipped band 113 (an example of the first part of this disclosure) includes one engaging projection 114 that constitutes the first engaging projection row L1. On the other hand, a part 113b of the projection-equipped band 113 (an example of the second part of this disclosure) includes one engaging projection 114 that constitutes the second engaging projection row L2.

[0091] This method also achieves the same effects as the above embodiment.

[0092] The numerical values ​​shown in the above embodiments are all examples, and it goes without saying that other appropriate numerical values ​​can be used.

[0093] The embodiments described above are merely illustrative in all respects. The invention is not to be construed as being limited by the descriptions of the embodiments above. The invention can be carried out in various other ways without departing from its spirit or main features. [Explanation of symbols]

[0094] 10...First housing section, 11...First strip-shaped member, 12...First flat strip section, 14...Engaging pin, 16...Weld mark, 20...Second housing section, 21...Second strip-shaped member, 22...Second flat strip section, 24...Engaging hole, 30...Guide section, 32...Guide member, 40...Drive section, 50...Cap section, 60...Telescopic device (helical reciprocating device), 70...Die, 71...Punch, 72...Punch, 73...Punch, 100...Helical winding type telescopic shaft (Cylindrical expandable body), 110...First strip-shaped member (first strip material), 111...First flat strip portion, 111i...Inner surface, 111o...Outer surface, 112...First engaging portion, 114...First hollow projection (engaging projection), 116...Opening, 118...Hole, 120...Second strip-shaped member (second strip material), 121...Second flat strip portion, 122...Second engaging portion, 124...Second hollow projection portion, 126...Opening, 210...First strip-shaped member, 211...First flat strip portion , 212...First engaging portion, 214...First hollow projection, 216...Top, 310...First strip-shaped member, 311...First flat strip portion, 312...First engaging portion, 314...First hollow projection, 316...Top, 318...Notch, 400...Spiral winding telescopic shaft, 410...First strip-shaped member, 411...First flat strip portion, 412...First engaging portion, 414...First hollow projection, 416...Opening, 420...Second strip-shaped member, 421 ...Second flat strip portion, 422...Second engaging portion, 500...Spiral winding telescopic shaft, 510...First strip-shaped member, 511...First flat strip portion, 512...First engaging portion, 514...First hollow projection portion, 516...Opening, 520...Second strip-shaped member, 521...Second flat strip portion, 522...Second engaging portion, 524...Peripheral portion, CX...Axis, L1...First row of engaging projections, L2...Second row of engaging projections, L3...First row of engaging portions, L4...Second row of engaging portions

Claims

1. A spiral extension and retraction device is formed by spirally overlapping and winding a first strip and a second strip, which is positioned inside the first strip, around a common axis, with the strips offset from each other in the axial direction, thereby forming a cylindrical extendable body. The first strip material comprises a first row of engaging protrusions and a second row of engaging protrusions, which are arranged in the longitudinal direction and consist of a plurality of engaging protrusions that are convex toward the axis, The second strip material comprises a first row of engaging portions and a second row of engaging portions, each consisting of a plurality of engaging portions arranged in its longitudinal direction. The engagement portion is configured such that the engagement projection can engage with the first strip material and the second strip material in a spiral manner when they are wrapped around each other. The portion of the first strip material that has higher rigidity than the surrounding area is a helical reciprocating mechanism that is pre-curved into a cylindrical shape corresponding to the tubular expandable body by press molding.

2. The first strip material includes flat strip portions and strip portions with engaging projections arranged alternately in its longitudinal direction. The band portion with the engaging projection includes one of the engaging projections that constitutes the first row of engaging projections and one of the engaging projections that constitutes the second row of engaging projections. The spiral reciprocating operating device according to claim 1, wherein the portion of the first strip material that has higher rigidity than the surrounding area is the strip portion with the engaging projection.

3. The spiral reciprocating device according to claim 2, wherein the band portion with the engaging projection is inclined at a predetermined angle with respect to the short direction of the first band material.

4. The spiral reciprocating device according to claim 2 or 3, wherein the portion of the first strip material that has higher rigidity than the surrounding area is a first portion of the strip portion with engaging protrusions that includes one of the engaging protrusions that constitutes the first row of engaging protrusions and a second portion that includes one of the engaging protrusions that constitutes the second row of engaging protrusions.

5. The spiral reciprocating device according to claim 1, wherein the radius of the cylindrical shape is greater than or equal to the radius of the cylindrical expandable body.

6. The spiral reciprocating device according to claim 5, wherein the radius of the cylindrical shape increases as it moves away from the engaging projection in the longitudinal direction of the first strip material.

7. The spiral reciprocating device according to claim 1, wherein the engaging projection is a hollow projection integrally formed on the first strip material.

8. The spiral reciprocating device according to claim 7, wherein the hollow projection is a hollow frustoconical projection.

9. A strip material used as the first or second strip material of a spiral extension and retraction device that constitutes a cylindrical expandable body by spirally overlapping and winding a first strip material and a second strip material placed inside the first strip material around a common axis, with the strip materials offset from each other in the axial direction, The strip material is provided with a first row of protrusions and a second row of protrusions, which are arranged in the longitudinal direction of the strip material and are convex toward the axis, The portion of the aforementioned strip material that has higher rigidity than the surrounding area is a tubular expandable body strip material that is pre-curved into a cylindrical shape corresponding to the tubular expandable body by press molding.

10. A method for manufacturing a tubular expandable material according to claim 9, A method for manufacturing a tubular expandable strip material, comprising press molding the strip material using a first mold including a first convex portion corresponding to the projection and a second convex portion corresponding to the cylindrical shape, and a second mold including a first concave portion corresponding to the first convex portion and a second concave portion corresponding to the second convex portion, thereby simultaneously forming the projection and the cylindrical shape.

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