JP4732293B2 - Combined spring - Google Patents

Description

  The present invention relates to a combined spring, and more particularly to a combined spring in which two torsion springs are combined into a thin shape.

  BACKGROUND ART Torsion springs (torsion coil springs) that use elasticity generated by twisting a coil spring wound around a steel wire are used in various forms in order to move and stop mechanical parts of electronic equipment. For example, it is used to slide a display unit of a mobile phone. Further, it is used to stably hold the display unit in the vertical position and the horizontal position when rotating the display unit.

  The elasticity of the torsion spring is adjusted by the wire thickness and winding diameter. The number of turns is adjusted by the amount of angle that can be twisted to the maximum during use. When the wire diameter and the winding diameter are the same, the maximum allowable stress and the moment (elasticity) at that time are almost constant even if the number of turns is changed. What changes is the amount of twist angle. With a small number of turns, the torsion spring constant is large, and the maximum allowable stress is reached with a small amount of angle. As the number of turns increases, the torsion spring constant decreases and the amount of angle increases. If the amount of twist angle used is large, the number of turns must be increased. Otherwise, it will lead to spring breakage and the like. As a strong torsion spring, there is a double torsion spring in which two springs are connected in the axial direction of a coil. Below, some examples of prior art relating to torsion springs used in electronic devices will be given.

  The “torsion spring” disclosed in Patent Document 1 can set a biasing force for a slide door having a large stroke length of a magnetic tape cartridge with a high degree of freedom, and can provide a desired door biasing force without requiring a shape of the slide door. It is a spring that can be obtained. As shown in FIG. 3A, as a biasing means for biasing the slide door to the closed position, a first coil portion, a pair of second coil portions, and a pair of bridges bridging these coil portions. And a torsion spring provided integrally with a pair of arm portions. If the arm part is inclined in the thickness direction of the slide door (the height direction of the coil part) from the starting end to the projecting end, the arm part bites between the slide door and the side wall of the guide groove. Is prevented.

  The “portable electronic device” disclosed in Patent Document 2 is a portable electronic device in which a movable unit is slid with respect to a fixed unit with a small resistance to reduce wear between them. As shown in FIG. 3B, the mobile phone has a fixed unit on the main body side and a display unit such as a liquid crystal display, and is movable so as to be relatively slidable along one surface of the fixed unit. It consists of units. The movable unit elastic holding means includes a torsion spring provided between the fixed unit and the movable unit. The end of the torsion spring on the movable unit side is latched by an engagement pin that passes through the long hole of the movable unit. The engaging pin is engaged with the sliding surface of the fixed unit. The movable unit is held in the holding position when the unstable intermediate point of the torsion spring is exceeded.

The “slide mechanism of a portable terminal” disclosed in Patent Document 3 is a slide mechanism that can automatically open and close from a predetermined slide position of the first casing and the second casing. As shown in FIG. 3C, this is a mechanism for relatively sliding the first casing and the second casing in a state where they are superposed in the vertical direction. A slide case is attached to one of the first housing and the second housing, and a slider is slidably attached to the slide case on the other. Elastic means is provided between the slider and the slide case. The elastic means slides and biases the slider from the predetermined sliding position in the closing / opening direction. The elastic means is a torsion spring. One end is pivotally supported on the base member, and the other end is pivotally supported on the slider. The position of the winding part is displaced by the sliding operation of the slider.
JP 2002-304864 JP JP 2005-159633 A JP 2005-210649 A

  However, the conventional torsion spring has the following problems. If a thick wire is used to increase the elasticity of the torsion spring, or if the number of turns is increased to increase the amount of torsion angle, the torsion spring becomes thick and cannot be incorporated into a thin electronic device.

  An object of the present invention is to solve the above-mentioned conventional problems and to thin a torsion spring having a strong elasticity used by being incorporated in an electronic device.

  In order to solve the above-mentioned problem, in the present invention, the first torsion spring of the combined spring that is used as one spring by combining the first torsion spring and the second torsion spring that utilize the elasticity generated by twisting the coil spring, The first torsion spring includes a first winding portion having a large diameter, a first arm portion extending from one end of the first winding portion, and a second arm portion extending from the other end of the first winding portion. A second winding portion having a small diameter, a third arm portion extending from one end of the second winding portion, and a fourth arm portion extending from the other end of the second winding portion. The second winding part is put in the part and overlapped, the first arm part and the third arm part are overlapped to form the first attachment part, and the second arm part and the fourth arm part are overlapped to form the second attachment part. The configuration is as follows. The ends of the first arm portion, the second arm portion, the third arm portion, and the fourth arm portion are formed in a circular shape. The winding direction of the end portions of the first arm portion and the second arm portion is the same as the winding direction of the first winding portion, and the winding direction of the end portions of the third arm portion and the fourth arm portion is the second winding direction. It is the reverse of the winding direction of the line part.

  By configuring as described above, a strong torsion spring used by being incorporated in an electronic device can be thinned. In the case of a single spring, the thickness increases when the wire is thickened to increase the elasticity, but the elasticity can be increased and the thickness can be prevented by using two springs. Since the amount of twist angle can be increased without increasing the number of windings, a significant reduction in thickness can be achieved. By using two springs, even if the wire diameter of each spring is small, elasticity equal to or greater than that of a single spring can be obtained. Since the spring constant decreases as the wire diameter decreases, the amount of twist angle can be increased without increasing the number of turns. Further, by reversing the winding direction of the end of the arm portion of one torsion spring with respect to the winding portion, the number of turns can be slightly increased, and interference between the arm portions can be prevented.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to FIGS. 1 and 2. FIG.

  The embodiment of the present invention is a thin and strong combination spring combining two torsion springs.

  FIG. 1 is a plan view and a side view of a combination spring in an embodiment of the present invention. Fig.1 (a) is a figure which shows the inner side torsion spring which has a winding part with a small diameter. FIG.1 (b) is a figure which shows the outer side torsion spring which has a winding part with a large diameter. FIG.1 (c) is a top view of the combination type spring which piled up two torsion springs. FIG. 2 is a diagram illustrating an assembly procedure of the combination spring.

  1 and 2, the inner torsion spring 1 is a torsion spring having a winding portion with a small diameter. The outer torsion spring 2 is a torsion spring having a winding portion with a large diameter. The combination spring 3 is a spring that combines an inner torsion spring and an outer torsion spring. The winding portion 4 is a small-diameter winding portion of the inner torsion spring. The arm portion 5 is a reversely wound arm portion of the inner torsion spring. The winding portion 6 is a large-diameter winding portion of the outer torsion spring. The arm portion 7 is a forward winding arm portion of the outer torsion spring. The attachment part 8 is a part which overlaps two arm parts to form an attachment part. The end portion of the arm portion is formed in a circular shape, but is not necessarily circular, and may be formed in a J shape or the like.

  As shown to Fig.1 (a), the inner side torsion spring 1 winds a steel wire twice, forms the coil | winding part 4, and makes the arm part 5 of both ends reversely wind. Although the arm portion 5 may be forward wound, when the reverse winding is performed, the inner torsion spring 1 can increase the number of turns although it is slight. As shown in FIG.1 (b), the outer side torsion spring 2 winds a steel wire twice, forms the coil | winding part 6, and makes the arm part 7 of both ends forward. As shown in FIG. 1C, the winding portion 4 of the inner torsion spring 1 is sized to fit within the ring of the winding portion 6 of the outer torsion spring 2. By reversing the winding direction of the arm portion 5 of the inner torsion spring 1, the number of turns of the winding portion 4 can be slightly increased. Since the inner torsion spring 1 has a reduced diameter of the winding portion 4 and severe stress conditions for satisfying the required elasticity, it is necessary to increase the number of turns as much as possible. Further, by reversing the winding direction, the distance from the arm portion 7 of the outer torsion spring 2 can be increased. If the arm portions interfere with each other, unnecessary resistance is generated, which promotes spring breakage due to repetitive operation, but there is an effect of preventing this by increasing the distance between the arm portions.

  Next, the assembly procedure of the combination spring will be described with reference to FIG. As shown in FIG. 2A, an inner torsion spring 1 and an outer torsion spring 2 are prepared. As shown in FIG. 2 (b), the winding portion 4 of the inner torsion spring 1 is put into the winding portion 6 of the outer torsion spring 2. As shown in FIG. 2 (c), the inner torsion spring 1 is overlapped with the outer torsion spring 2. As shown in FIG. 2D, the assembly is completed by overlapping the arm portion 5 of the inner torsion spring 1 and the arm portion 7 of the outer torsion spring 2.

  Since two torsion springs are combined in this way, a strong elasticity can be obtained. Further, since the two torsion springs are nested concentrically, the thickness can be reduced. For example, if you use one spring of 3 turns with a wire diameter of 0.5 mmφ, the thickness will be 2.0 mm. If you use two springs with a wire diameter of 0.4mmφ, the thickness will be 1.2mm with the same elasticity, and the thickness can be reduced to 0.8mm. Although the example which combined two torsion springs was demonstrated, the same effect can be acquired even if it combines three or more torsion springs.

  As described above, in the embodiment of the present invention, since the two torsion springs are combined, a strong spring can be thinned.

  The torsion spring of the present invention is optimal as a position holding spring for thin portable devices.

It is the top view and side view of the combination type spring in the Example of this invention. It is a figure which shows the assembly procedure of the combination type spring in the Example of this invention. It is a conceptual diagram which shows the usage pattern of the conventional torsion spring.

Explanation of symbols

1 Inner torsion spring 2 Outer torsion spring 3 Combined spring 4 Winding part (small diameter)
5 arms (reverse winding)
6 Winding part (large diameter)
7 arms (in order)
8 Mounting part

Claims (1)

A combined spring that is used as a single spring by combining a first torsion spring and a second torsion spring that use elasticity generated by twisting a coil spring, and the first torsion spring is formed by winding a steel wire twice. A planar first winding portion having a large diameter; a first arm portion extending from one end of the first winding portion; and a second arm portion extending from the other end of the first winding portion; The second torsion spring includes a flat second winding portion formed by winding a steel wire twice, a third arm portion extending from one end of the second winding portion, and the second winding. A fourth arm portion extending from the other end of the line portion, the first arm portion, the second arm portion, the third arm portion, and the end of the fourth arm portion are formed in a circular shape, The winding direction of the end portions of the first arm portion and the second arm portion is the same as the winding direction of the first winding portion, and the third arm portion and the fourth arm portion are the same. Winding direction of the end portion of the parts are winding direction opposite said second winding portion, overlapped to put the second winding part in said first winding portion, the said first arm portion first A combined spring, wherein three arm portions are overlapped to form a first attachment portion, and the second arm portion and the fourth arm portion are overlapped to form a second attachment portion.

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