Twisted coil screw device

Abstract

To provide a twisted coil screw device which can prevent fatigue of an arm part with a more simple configuration while permitting inclination of a coil part with respect to a guide rod when a load is applied.SOLUTION: A twisted coil screw device includes: a twisted coil screw 11 having a coil part 11A; one arm part 11B extending from one side of the coil part and the other arm part 11C extending from the other side of the coil part; and a base part 12 having a guide rod 12A inserted on an inner diameter side of the coil part. The twisted coil screw device includes at least one of: one friction reduction member 13A which is provided on one side of the guide rod and reduces friction of a contact part 11V on one inner peripheral part when one inner peripheral part 11D of the coil part comes into contact; and the other friction reduction member 13B which is provided on the other side of the guide rod and reduces friction of a contact part 11W on the other inner peripheral part when the other inner peripheral part 11E of the coil part comes into contact.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a torsion coil spring device. [Background technology]

[0002] A torsion coil spring is a spring that receives a torsional moment around the central axis of the coil. When a load is applied to the spring, it generates bending stress and rotates, and the elastic energy caused by the load is stored as bending elastic energy. Torsion coil springs are used in various rotating devices that require elastic force, and to ensure proper operation of the torsion coil spring, a guide rod is generally inserted into the hollow space inside the coil.

[0003] At one end and the other end of the torsion coil spring, an arm portion is formed extending from the coil portion, and a load is applied to the arm portion. The load applied to the torsion coil spring is generally a load in a direction that reduces the diameter of the coil portion (a load in the coil winding direction). The cross-sectional area of ​​the guide rod is set to about 90% of the cross-sectional area of ​​the inner side of the coil portion so as not to hinder the rotation of the spring when a load is applied in a direction that reduces the diameter of the coil portion. Therefore, a gap of a predetermined distance is intentionally set between the inner circumferential side of the coil portion and the outer circumferential side of the guide rod, and this gap causes the central axis of the coil portion to tilt with respect to the central axis of the guide rod when a load is applied to the coil portion.

[0004] For example, when a load in the diameter-reducing direction is applied to the arm portion, the coil portion becomes tilted relative to the guide rod, and the inner periphery of the coil portion closest to the arm portion to which the load is applied comes into contact with the guide rod. If the friction at the contact point between the inner periphery of the coil portion and the guide rod is small, the contact point moves circumferentially around the outer periphery of the guide rod in response to the load, causing stress due to the load to be applied to the entire coil portion, reducing the diameter of the entire coil portion. However, if the friction at the contact point between the inner periphery of the coil portion and the guide rod is large, the contact point cannot move circumferentially around the outer periphery of the guide rod in response to the load, and the stress due to the load is concentrated on the arm portion with the contact point as a fulcrum, causing the arm portion to bend without reducing the diameter of the coil portion. If this bending of the arm portion is repeated, so-called "sag" progresses, and the intended elastic force cannot be obtained.

[0005] For example, Patent Document 1 discloses a torsion spring device in which the inner diameter of one end of the coil is set to be the same as or smaller than that of a guide rod, and the inner diameter of portions of the coil other than the one end (the other end and the portion from the other end to the one end) is set to be larger than that of the guide rod. When a torsion coil spring is attached to a guide rod, the arm portion on one end of the coil that contacts the guide rod is fixed relative to the guide rod, and a load is applied to the arm portion on the other end of the coil that has a gap between it and the guide rod. The central axis of the guide rod and the central axis of the torsion coil spring remain aligned regardless of whether a load is applied, and the torsion coil spring does not tilt relative to the guide rod even when a load is applied. Even when a load is applied to the arm portion on the other end of the coil, the coil does not tilt relative to the guide rod, and only one end of the coil is in contact with the guide rod, so the elastic energy due to the load is propagated throughout the entire coil, preventing so-called "sag." [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 63-076929 Summary of the Invention [Problem to be solved by the invention]

[0007] In the torsion spring device described in Patent Document 1, the inner diameter of one end of the coil portion of the torsion coil spring is set to be the same as or smaller than the guide rod, while the inner diameter of portions other than the one end of the coil portion (the other end and the portion from the other end to the one end) is set to be larger than the guide rod, which is undesirable because it results in a complex shape (structure) of the coil portion. Furthermore, if the one end of the coil portion is not firmly fixed to the guide rod, the coil portion will tilt relative to the guide rod when a load is applied. In Patent Document 1, the one end of the coil portion must be firmly fixed to the guide rod so that the coil portion does not tilt relative to the guide rod whether a load is applied or not. Therefore, it is difficult to make the diameter of the guide rod and the inner diameter of the one end of the coil portion the same, taking into account variations. Furthermore, if the inner diameter of the one end of the coil portion is smaller than the guide rod, it is undesirable because it requires a lot of work to attach the coil portion to the guide rod.

[0008] The present invention was devised in light of these points, and its object is to provide a torsion coil spring device that can prevent sagging of the arm portion with a simpler structure while allowing the coil portion to tilt relative to the guide rod when a load is applied. [Means for solving the problem]

[0009] In order to solve the above problems, a first invention is a torsion coil spring device including a coil portion formed by winding a spring material in a coil shape, a first arm portion extending from one axial side of the coil portion, and a second arm portion extending from the other axial side of the coil portion, and a base portion having a guide rod inserted into the inner diameter side of the coil portion, wherein the guide rod has at least one of: a first friction reduction member provided on one side of the outer circumferential surface of the guide rod, the first friction reduction member reducing friction at a contact point of the first inner circumferential portion when the first inner circumferential portion contacts the inner circumferential portion of the one side of the coil portion; and a second friction reduction member provided on the other side of the outer circumferential surface of the guide rod, the second friction reduction member reducing friction at a contact point of the second inner circumferential portion when the second inner circumferential portion contacts the inner circumferential portion of the other side of the coil portion.

[0010] Next, a second invention is a torsion coil spring device according to the first invention, wherein the one arm portion is arranged so as to be movable relative to the guide rod, the other arm portion is arranged so as to be fixed relative to the guide rod, and the one friction reducing member is provided on the guide rod without the other friction reducing member being provided.

[0011] Next, a third invention is a torsion coil spring device according to the first invention, wherein each of the one arm portion and the other arm portion is arranged to be movable relative to the guide rod, and the one friction reduction member and the other friction reduction member are provided on the guide rod.

[0012] Next, a fourth invention is a torsion coil spring device according to the first invention, wherein the length of at least one of the one friction reduction member and the other friction reduction member in the axial direction of the guide rod is set to be longer than the diameter of the spring material and less than half the axial length of the coil portion. [Effects of the Invention]

[0013] According to the first aspect of the present invention, when a load is applied to one arm or the other arm of the torsion coil spring, the coil portion tilts relative to the guide rod, causing one inner circumferential portion of the coil portion to contact the guide rod, and the other inner circumferential portion of the coil portion to contact the guide rod. However, by including at least one of a one-side friction-reducing member that reduces friction at the contact point between one inner circumferential portion of the coil portion and one side of the guide rod, or a second-side friction-reducing member that reduces friction at the contact point between the other inner circumferential portion of the coil portion and the other side of the guide rod, the contact point can be easily moved circumferentially. This allows the applied load to be transmitted from the arm to which the load is applied to the entire coil portion without being concentrated at the contact point. Therefore, it is possible to prevent sagging of the arm portion with a simpler structure while allowing the coil portion to tilt relative to the guide rod when a load is applied.

[0014] According to the second aspect of the present invention, the one arm portion is an arm portion to which a load is applied, and the other arm portion is an arm portion to which a load is not applied, and the one arm portion is movable relative to the guide rod, while the other arm portion is fixed relative to the guide rod. As a result, when a load is applied to the one arm portion, the contact point of the one inner periphery of the coil portion moves circumferentially relative to the guide rod, but the contact point of the other inner periphery of the coil portion hardly moves circumferentially relative to the guide rod. Therefore, when the arm portion to which a load is applied is the one arm portion and the other arm portion is fixed relative to the guide rod, the one-side friction reducing member is necessary, but the other-side friction reducing member can be omitted.

[0015] According to the third aspect of the present invention, a load is applied to both the first arm and the second arm, and both arm portions are movable relative to the guide rod. When a load is applied to the first arm, the first friction reduction member allows the contact point of the first inner periphery of the coil portion to easily move circumferentially relative to the guide rod, so that the stress caused by the load can be transmitted to the entire coil portion. Similarly, when a load is applied to the other arm, the second friction reduction member allows the contact point of the other inner periphery of the coil portion to easily move circumferentially relative to the guide rod, so that the stress caused by the load can be transmitted to the entire coil portion.

[0016] According to the fourth aspect of the present invention, the lengths of the first friction reducing member and the second friction reducing member in the axial direction of the guide rod can be set to appropriate lengths. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a diagram illustrating an example in which a tension applying device including a torsion coil spring device is applied to a timing chain of an internal combustion engine. [Figure 2] 1A and 1B are diagrams illustrating an example of the appearance of a tension applying device including a torsion coil spring device. [Figure 3] 1A and 1B are diagrams illustrating factors that cause "sag" when a load in the diameter-reducing direction is applied to a torsion coil spring. [Figure 4] 1A and 1B are diagrams illustrating factors that cause "sag" when a load in the radial expansion direction is applied to a torsion coil spring. [Figure 5] This is a cross section taken along line VV in FIG. [Figure 6] FIG. 1 is an exploded perspective view of a torsion coil spring device according to a first embodiment. [Figure 7] 10A and 10B are diagrams illustrating an example of a state in which a load is applied to one arm portion of the torsion coil spring device of the first embodiment, and stress is distributed over almost the entire one arm portion and the coil portion. [Figure 8]10A and 10B are diagrams illustrating an example of a state in which a load is applied to one arm of a conventional torsion coil spring device, and stress is concentrated on the one arm. [Figure 9] 10 is a cross-sectional view of a torsion coil spring device according to a second embodiment. [Figure 10] 10A and 10B are diagrams illustrating an example in which a load in the diameter-reducing direction is applied to one arm of the torsion coil spring device of the third embodiment. [Figure 11] 10A and 10B are diagrams illustrating an example in which a load in the radial expansion direction is applied to one arm portion of the torsion coil spring device of the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] <Application example of tension applying device 2 equipped with torsion coil spring device 10 (Figs. 1 and 2)> A torsion coil spring device 10 of the present invention will be described below with reference to the drawings. First, an example in which a tension applying device 2 equipped with a torsion coil spring device 10 is applied to an internal combustion engine 1 will be described using Figure 1. Note that when an X-axis, a Y-axis, and a Z-axis are shown in the figure, the X-axis, the Y-axis, and the Z-axis are perpendicular to one another.

[0019] In the internal combustion engine 1 shown in Fig. 1, a timing chain 6 is stretched around a crank gear 3 connected to a crankshaft, a cam gear 4 connected to an intake camshaft, and a cam gear 5 connected to an exhaust camshaft. The timing chain 6 causes the intake camshaft and the exhaust camshaft to rotate in synchronization with the rotation of the crankshaft. The tensioning device 2 is provided in a position where it comes into contact with the timing chain 6.

[0020] 2, the tension applying device 2 includes a torsion coil spring device 10 having a torsion coil spring 11 and a base portion 12, and a pressing member 20 that swings around a swing center axis 20Z. For example, the diameter of the spring material of the torsion coil spring 11 is approximately 4 mm, and the inner diameter of the coil portion is approximately 16 mm. The tension applying device 2 presses the pressing member 20 from the torsion coil spring device 10 toward the timing chain 6 with a predetermined tension, thereby maintaining the tension of the timing chain 6 at the predetermined tension.

[0021] Timing chain 6 oscillates pressing member 20 at various cycles and amplitudes on one arm 11B of torsion coil spring 11, and loads of various cycles and amplitudes are applied to one arm 11B. In a conventional tension applying device equipped with a conventional torsion coil spring device, this load can cause so-called "sag" in the torsion coil spring, making it impossible to obtain the desired tension. The tension applying device 2 equipped with torsion coil spring devices 10, 10B, and 10C of the present invention, which will be described below, prevents the torsion coil spring from "sagging" and can maintain the desired tension for a long period of time.

[0022] <Causes of "sag" in torsion coil springs (Fig. 3, Fig. 4)> 3 shows an example of a state in which a load F1 in the diameter contraction direction is applied to one arm portion 81B of torsion coil spring 81, to which guide rod 82A is inserted into the inner diameter side and other arm portion 81C is fixed. Note that guide rod 82A is fixed and does not rotate.

[0023] 3, in a state (natural state) in which no load F1 in the diameter-reducing direction is applied to torsion coil spring 81, "spring position P1" of torsion coil spring 81 is in contact with "outer peripheral position Q11" of guide rod 82A. When load F1 in the diameter-reducing direction is applied from this position to one arm portion 81B, one arm portion 81B moves (rotates) as shown by the dotted line in FIG. 3, and coil portion 81A contracts in diameter.

[0024] Before the load F1 is applied (when the torsion coil spring is in its natural state), the "spring position P1" is in contact with the "outer peripheral position Q11" of the guide rod 82A. When the load F1 is applied and the one arm portion 81B moves (pivots) as shown by the dotted line, the "spring position P1" moves circumferentially along the outer peripheral surface of the guide rod 82A to the "outer peripheral position Q12" of the guide rod 82A. Then, the diameter of the coil portion 81A decreases.

[0025] At this time, if the friction at the contact point between "spring position P1" and "from outer peripheral position Q11 to outer peripheral position Q12" is sufficiently small, "spring position P1" will move from "outer peripheral position Q11" to "outer peripheral position Q12", causing the coil portion 81A to contract in diameter, and the stress due to load F1 will be applied to the entire coil portion 81A of the torsion coil spring 81, so there will be no problem and "sagging" will not occur.

[0026] However, if there is a large friction at the contact point between "spring position P1" and "from outer peripheral position Q11 to outer peripheral position Q12," "spring position P1" cannot move from "outer peripheral position Q11" to "outer peripheral position Q12" and remains at "outer peripheral position Q11." In this case, the stress from load F1 is not applied to the entire coil portion 81A, but is concentrated on "from spring position P1 to the tip of one arm portion 81B" as a bending stress that bends "from spring position P1 (the point of contact with guide rod 82A) to the tip of one arm portion 81B" with spring position P1 as the fulcrum. If stress exceeding the allowable amount is repeatedly applied to "from spring position P1 to the tip of one arm portion 81B," "sag" occurs in "from spring position P1 to the tip of one arm portion 81B."

[0027] 4 shows an example of a state in which a load F2 in the radial expansion direction is applied to one arm portion 81B of torsion coil spring 81, with guide rod 82A inserted into the inner diameter side and other arm portion 81C fixed. Note that guide rod 82A is fixed and does not rotate. Note that torsion coil springs are generally designed to withstand loads in the radial contraction direction and not loads in the radial expansion direction, but in this embodiment, an example will be described in which a load in the radial expansion direction is also assumed.

[0028] 4, in a state (natural state) in which no load F2 in the radial expansion direction is applied to torsion coil spring 81, "spring position P2" of torsion coil spring 81 is in contact with "outer peripheral position Q21" of guide rod 82A. When load F2 in the radial expansion direction is applied to one arm portion 81B from this position, one arm portion 81B moves (rotates) as shown by the dotted line in FIG. 4, and the diameter of coil portion 81A expands.

[0029] Before the load F2 is applied (in its natural state), the "spring position P2" is in contact with the "outer peripheral position Q21" of the guide rod 82A. After the load F2 is applied and the one arm portion 81B moves (pivots) as shown by the dotted line, the "spring position P2" moves circumferentially from the "outer peripheral position Q21" of the guide rod 82A to the "outer peripheral position Q22" of the guide rod 82A while contacting the outer peripheral surface of the guide rod 82A. Then, the diameter of the coil portion 81A expands.

[0030] At this time, if the friction at the contact point between "spring position P2" and "from outer peripheral position Q21 to outer peripheral position Q22" is sufficiently small, "spring position P2" will move from "outer peripheral position Q21" to "outer peripheral position Q22", causing the coil portion 81A to expand in diameter, and the stress due to load F2 will be applied to the entire coil portion 81A of the torsion coil spring 81, so there will be no problem and "sagging" will not occur.

[0031] However, if there is a large friction at the contact point between "spring position P2" and "from outer peripheral position Q21 to outer peripheral position Q22," "spring position P2" cannot move from "outer peripheral position Q21" to "outer peripheral position Q22" and will remain at "outer peripheral position Q21." In this case, the stress from load F2 is not applied to the entire coil portion 81A, but is concentrated on "from spring position P2 to the tip of one arm portion 81B" as a bending stress that bends "from spring position P2 (the point of contact with guide rod 82A) to the tip of one arm portion 81B" with spring position P2 as the fulcrum. If stress exceeding the allowable amount is repeatedly applied to "from spring position P2 to the tip of one arm portion 81B," "sag" will occur in "from spring position P2 to the tip of one arm portion 81B."

[0032] The "torsion coil spring devices 10, 10B, 10C" described below can prevent "sagging" by reducing the circumferential friction at the contact point between the above-mentioned "spring position P1" and "from outer peripheral position Q11 to outer peripheral position Q12" and the circumferential friction at the contact point between the above-mentioned "spring position P2" and "from outer peripheral position Q21 to outer peripheral position Q22."

[0033] <Structure of the torsion coil spring device 10 according to the first embodiment (FIGS. 5 and 6)> As shown in FIGS. 5 and 6, the torsion coil spring device 10 of the first embodiment has a torsion coil spring 11 and a base portion 12. The torsion coil spring 11 has a coil portion 11A, a first arm portion 11B, and a second arm portion 11C. The coil portion 11A is formed by winding a spring material in a coil shape several times. The first arm portion 11B extends from one side of the coil portion 11A in the axial direction. The second arm portion 11C extends from the other side of the coil portion 11A in the axial direction. The base portion 12 has a guide rod 12A that is inserted into the inner diameter side of the coil portion 11A. Note that the torsion coil spring 11 described in this embodiment shows an example in which the tip of the first arm portion 11B and the tip of the second arm portion 11C are bent to one side.

[0034] 5, one arm portion 11B is provided so as to be movable relative to guide rod 12A, and the other arm portion 11C is provided so as to be fixed relative to guide rod 12A. Because the outer diameter of guide rod 12A is set to be smaller than the inner diameter of torsion coil spring 11, when a load F1 in the diameter-reducing direction is applied to one arm portion 11B of torsion coil spring 11, spring central axis 11Z is inclined at an inclination angle θ1 with respect to guide rod central axis 12Z.

[0035] As shown in FIGS. 5 and 6, one friction reduction member 13A, a first spacer 14B, an other friction reduction member 13B, and a second spacer 14C are fitted onto the guide rod 12A from one side to the other. They are fixed with fastening members 14A (e.g., bolts), washers 14D, and fastening members 14E (e.g., nuts), and the one friction reduction member 13A to the second spacer 14C are integrated with the guide rod 12A. The guide rod 12A, which is integrated with the one friction reduction member 13A, etc., is inserted through the inner diameter side of the torsion coil spring 11. As shown in FIG. 5, the torsion coil spring 11 is prevented from slipping out to one side by a flange portion formed at one end of the guide rod 12A and the body of the base portion 12 (see FIG. 6). Also as shown in FIG. 5, the torsion coil spring 11 is prevented from slipping out to the other side by a flange portion formed at the other end of the second spacer 14C and a washer 14D.

[0036] 6 is an exploded perspective view of the torsion coil spring device 10. The base portion 12 has a guide rod 12A and a spring fixing portion 12B. The guide rod 12A has a first opposing surface 12D that faces the inner periphery of one side of the torsion coil spring 11, and a second opposing surface 12E that faces the inner periphery of the other side of the torsion coil spring 11.

[0037] The inner diameters of the one friction reducing member 13A, the first spacer 14B, and the other friction reducing member 13B, and the second spacer 14C are set to be the same as or slightly larger than the outer diameter of the guide rod 12A. Also, the inner diameter of the coil portion 11A of the torsion coil spring 11 is set to be slightly larger than the outer diameters of the one friction reducing member 13A, the first spacer 14B, and the other friction reducing member 13B, and the second spacer 14C (excluding the flange portions).

[0038] As shown in Fig. 6, when assembling torsion coil spring device 10, first, first friction reduction member 13A, first spacer 14B, and second friction reduction member 13B are attached to guide rod 12A. Then, torsion coil spring 11 is attached to guide rod 12A, and second arm portion 11C is fixed to fixing hole 12C of spring fixing portion 12B. Next, second spacer 14C is attached to guide rod 12A and fixed with fastening member 14A (such as a bolt), washer 14D, and fastening member 14E (such as a nut) (see Fig. 5).

[0039] 5, in torsion coil spring device 10 of the first embodiment, one side of the outer circumferential surface of guide rod 12A (the left side of guide rod 12A in FIG. 5) is provided with one-side friction reduction member 13A that reduces circumferential friction at contact point 11V of one-side inner circumferential portion 11D, which is the inner circumferential portion on one side of coil portion 11A, when it comes into contact with guide rod 12A. Since circumferential friction is reduced at contact point 11V of one-side inner circumferential portion 11D of torsion coil spring 11 with guide rod 12A (contact point 11V with one-side friction reduction member 13A), contact point 11V can be easily moved in the circumferential direction.

[0040] 5, torsion coil spring device 10 is provided with a second-side friction reducing member 13B on the other side of the outer circumferential surface of guide rod 12A (the right side of guide rod 12A in FIG. 5) that reduces circumferential friction at contact point 11W of second-side inner circumferential portion 11E, which is the inner circumferential portion on the other side of coil portion 11A, when the second-side inner circumferential portion 11E comes into contact with guide rod 12A. Since circumferential friction is reduced at contact point 11W of second-side inner circumferential portion 11E of torsion coil spring 11 with guide rod 12A (contact point 11W with second-side friction reducing member 13B), contact point 11W can be easily moved in the circumferential direction.

[0041] For example, rolling bearings (ball bearings, roller bearings, needle bearings), sliding bearings, etc. are used as the first friction reduction member 13A and the second friction reduction member 13B.

[0042] Furthermore, the axial lengths L1 and L2 (see FIG. 5) of the first friction reduction member 13A and the second friction reduction member 13B in the axial direction (Y-axis direction) of the guide rod 12A are set to be longer than the diameter LC of the spring material and less than half the axial length (Y-axis direction) of the coil portion 11A. By making the axial lengths L1 and L2 longer than the diameter LC of the spring material, a contact area between the first inner circumferential portion 11D of the coil portion 11A and the first friction reduction member 13A is secured, and a contact area between the second inner circumferential portion 11E of the coil portion 11A and the second friction reduction member 13B is secured. Furthermore, if the first friction reduction member 13A and the second friction reduction member 13B are, for example, rolling bearings, there is a possibility that the rolling amounts may differ. Therefore, a first spacer 14B is provided to prevent direct contact. Furthermore, by making the axial lengths L1 and L2 less than half the axial length (Y-axis direction) of the coil portion 11A, an area for the first spacer 14B is secured.

[0043] <Effects of the torsion coil spring device 10 (FIGS. 7 and 8)> 7 is an image diagram showing, by using shades of hatching, the magnitude of stress acting on each part of torsion coil spring 11 when a load F1 in the diameter-reducing direction is applied to one arm portion 11B of torsion coil spring device 10 of the first embodiment described above. When load F1 in the diameter-reducing direction is applied to one arm portion 11B, one friction reduction member 13A and the other friction reduction member 13B (see FIGS. 5 and 6) can easily move "spring position P1" shown in the example of FIG. 3 in the circumferential direction from "outer peripheral position Q11" to "outer peripheral position Q12."

[0044] Therefore, the stress due to load F1 is applied almost uniformly to the entire coil portion 11A so as to reduce the diameter of the entire torsion coil spring 11, and there are no areas where the stress is concentrated, thereby preventing the occurrence of "sag." Note that in Figure 7, the hatching density of each of the stresses 31, 32, 33, and 34 is almost the same, indicating that the magnitude of each stress is almost the same (the stress is applied uniformly).

[0045] 8 is an image diagram showing, by using shades of hatching, the magnitude of stress acting on each part of torsion coil spring 81 when a load F1 in the diameter contraction direction is applied to one arm portion 81B of conventional torsion coil spring device 110 that does not have one friction reduction member 13A and other friction reduction member 13B. When load F1 in the diameter contraction direction is applied to one arm portion 81B, since there is no one friction reduction member 13A or other friction reduction member 13B (see FIGS. 5 and 6), "spring position P1" shown in the example of FIG. 3 remains at "outer peripheral position Q11" due to frictional force and cannot move to "outer peripheral position Q12."

[0046] Therefore, the stress due to the load F1 is concentrated in the area "from spring position P1 to the tip of one arm" shown in Figure 3, and acts as a stress that bends "from spring position P1 to the tip of one arm," which may result in "sag." In Figure 8, among stresses 131, 132, 133, and 134, stress 131 has an exceptionally high concentration, and stresses 132, 133, and 134 are weaker than stress 131 and have approximately the same concentration. In Figures 7 and 8, stress 131 in Figure 8 has the highest concentration (the greatest stress is applied), indicating that stress is concentrated in the area "from spring position P1 (see Figure 3) to the tip of one arm 81B" in Figure 8.

[0047] <Structure of the torsion coil spring device 10B according to the second embodiment (FIG. 9)> Torsion coil spring device 10B of the second embodiment shown in Fig. 9 is different from torsion coil spring device 10 of the first embodiment shown in Fig. 5 in that second friction reduction member 13B is omitted. The first and second embodiments are the same in that first arm portion 11B is provided so as to be movable relatively to guide rod 12A, and second arm portion 11C is provided so as to be fixed relatively to guide rod 12A.

[0048] In the torsion coil spring device 10B of the second embodiment shown in Figure 9, it is assumed that one arm portion 11B is movable and a load (load in the diameter contraction direction or diameter expansion direction) is applied, but the other arm portion 11C is fixed and is not assumed to be directly subjected to a load. When a load is applied to one arm portion 11B, the circumferential movement distance of contact point 11V of one inner circumferential portion 11D of coil portion 11A is almost the same as the circumferential movement distance of contact point 11W of the other inner circumferential portion 11E of coil portion 11A. Therefore, as shown in the torsion coil spring device 10B shown in Figure 9, the other friction reduction member 13B (see Figure 5) may be omitted.

[0049] Note that instead of "one arm portion movable relative to the guide rod, the other arm portion fixed relative to the guide rod" (see Figure 9), it may be "one arm portion fixed relative to the guide rod, the other arm portion movable relative to the guide rod." In this case, when a load is applied to the other arm portion, the circumferential movement distance of the contact point on the one inner periphery of the coil portion is almost the same as the circumferential movement distance of the contact point on the other inner periphery of the coil portion. Therefore, in this case, the one friction reduction member may be omitted.

[0050] As shown in Fig. 9, in torsion coil spring device 10B of the second embodiment, the "second friction reduction member 13B+first spacer 14B" in torsion coil spring device 10 of the first embodiment shown in Fig. 5 is replaced with a "first spacer 14F." Note that "first spacer 14B+second friction reduction member 13B+second spacer 14C" may also be replaced with a "first spacer." Compared to torsion coil spring device 10 of the first embodiment (see Fig. 5), torsion coil spring device 10B of the second embodiment can omit second friction reduction member 13B, thereby reducing the number of parts.

[0051] <Structure of the torsion coil spring device 10C according to the third embodiment (FIGS. 10 and 11)> A torsion coil spring device 10C of a third embodiment shown in Figures 10 and 11 differs from the torsion coil spring device 10 of the first embodiment shown in Figure 5 in that it does not have a spring fixing portion 12B and a fixing hole 12C, and the other arm portion 11C is provided so as to be movable relatively to the guide rod 12A. In the third embodiment, as shown in Figures 10 and 11, the one arm portion 11B and the other arm portion 11C are each provided so as to be movable relatively to the guide rod 12A. Another difference is that the axial lengths L3 and L4 of the one friction reduction member 13C and the other friction reduction member 13D shown in Figures 10 and 11 are longer than the axial lengths L1 and L2 of the one friction reduction member 13A and the other friction reduction member 13B shown in Figure 5.

[0052] The first embodiment shown in FIG. 5 assumes that when a load is applied, the torsion coil spring 11 will incline in one direction relative to the guide rod 12A as shown in FIG. 5, whereas the third embodiment shown in FIGS. 10 and 11 assumes that when a load is applied, the torsion coil spring 11 will incline in two directions relative to the guide rod 12A as shown in FIGS. 10 and 11.

[0053] 10 shows a state in which a load F1 in the diameter-reducing direction is applied to one arm portion 11B (or a load F2 in the diameter-expanding direction is applied to the other arm portion 11C), causing the spring central axis 11Z to be inclined at an inclination angle θ1 with respect to the guide rod central axis 12Z. In this case, one inner circumferential portion 11D near one arm portion 11B of the torsion coil spring 11 contacts one friction reduction member 13C at a contact point 11V, and the other inner circumferential portion 11E near the other arm portion 11C of the torsion coil spring 11 contacts the other friction reduction member 13D at a contact point 11W.

[0054] 11 shows a state in which a load F2 in the diameter-expanding direction is applied to one arm portion 11B (or a load F1 in the diameter-contracting direction is applied to the other arm portion 11C), causing the spring central axis 11Z to be inclined at an inclination angle θ2 with respect to the guide rod central axis 12Z. In this case, one inner circumferential portion 11F of the torsion coil spring 11 opposite to one arm portion 11B contacts one friction reduction member 13C at a contact point 11X, and the other inner circumferential portion 11G of the torsion coil spring 11 opposite to the other arm portion 11C contacts the other friction reduction member 13D at a contact point 11Y.

[0055] In addition, in the examples of Figures 10 and 11, the axial length L3 of one friction reduction member 13C and the axial length L4 of the other friction reduction member 13D are set to be longer than twice the diameter LC of the spring material and less than half the axial length of the coil portion 11A.

[0056] The advantage of the torsion coil spring device 10C of the third embodiment compared to the torsion coil spring device 10 of the first embodiment (see FIG. 5) is that it is possible to provide a movable member (pressing member 20 shown in FIG. 2) not only on the side of one arm portion 11B but also on the side of the other arm portion 11C.

[0057] <Effects etc.> As described above, the torsion coil spring devices 10, 10B, and 10C described in this embodiment allow the coil portion to tilt relative to the guide rod when a load is applied, while preventing the arm portion from "sagging" with a simpler structure.

[0058] <Other> The torsion coil spring devices 10, 10B, and 10C of the present invention are not limited to the configuration, structure, shape, appearance, size, etc. described in this embodiment, and various modifications, additions, and deletions are possible within the scope that does not change the gist of the present invention.

[0059] The first and third embodiments have been described as examples of torsion coil spring devices 10 and 10C having one friction reduction member and the other friction reduction member, while the second embodiment has been described as an example of torsion coil spring device 10B having only one friction reduction member (or only the other friction reduction member). In other words, any torsion coil spring device may be used as long as it has at least one of one friction reduction member and the other friction reduction member.

[0060] In the description of this embodiment, an example has been given in which the torsion coil spring device of the present invention is applied to a tension applying device for an internal combustion engine, but the torsion coil spring device of the present invention is not limited to applying tension to an internal combustion engine, and can be applied to a variety of uses in a variety of equipment.

[0061] In the description of this embodiment, examples have been given in which rolling bearings (ball bearings, roller bearings, needle bearings), plain bearings (slide bearings), etc. are used as the one-side friction reduction member and the other-side friction reduction member, but anything that can reduce circumferential friction will do, and the members are not limited to bearings.

[0062] Furthermore, when greater than or equal to (≧), less than or equal to (≦), greater than, exceeding (>), less than (<), etc. are written, the equal sign may or may not be included. Furthermore, when numerical values ​​are written in the explanation of this embodiment, the numerical values ​​are merely examples and are not limited to these numerical values. [Explanation of symbols]

[0063] 1. Internal combustion engine 2 Tensioning device 3 crank gear 4, 5 Cam gear 6 Timing chain 10, 10B, 10C Torsion coil spring device 11 Torsion coil spring 11A Coil section 11B One arm 11C Other arm part 11D, 11F One inner circumference 11E, 11G Other inner circumference 11V, 11W, 11X, 11Y contact points 11Z Spring center axis 12 Base 12A Guide rod 12B Spring fixing part 12C fixing hole 12D One opposing surface 12E Other facing surface 12Z Guide rod center axis 13A, 13C One-side friction reducing member 13B, 13D Other friction reducing member 14A Fastening members 14B, 14F, 14G First spacer 14C Second spacer 14D washer 14E Fastening members 20 Pressing member 20Z Swing center axis 31, 32, 33, 34 Stress F1, F2 loads L1, L2, L3, L4 Axial length LC Spring material diameter P1, P2 spring position Q11, Q12, Q21, Q22 outer circumference position θ1, θ2 Tilt angle

Claims

1. a torsion coil spring including a coil portion formed by winding a spring material in a coil shape, one arm portion extending from one side of the coil portion in an axial direction, and another arm portion extending from the other side of the coil portion in the axial direction; a base portion having a guide rod inserted into the inner diameter side of the coil portion; A torsion coil spring device having The guide rod is a one-side friction reducing member provided on the one side of the outer circumferential surface of the guide rod, the one-side friction reducing member reducing friction at a contact point of the one-side inner circumferential portion when the one-side inner circumferential portion comes into contact with the one-side inner circumferential portion; a second friction reducing member provided on the second side of the outer circumferential surface of the guide rod, the second friction reducing member reducing friction at a contact point of the second inner circumferential portion when the second inner circumferential portion, which is an inner circumferential portion of the second side of the coil portion, comes into contact with the second inner circumferential portion; and Torsion coil spring device.

2. 2. The torsion coil spring device according to claim 1, the one arm portion is provided so as to be movable relative to the guide rod, the other arm portion is provided so as to be fixed relatively to the guide rod, the guide rod is provided with the one friction reducing member without being provided with the other friction reducing member; Torsion coil spring device.

3. 2. The torsion coil spring device according to claim 1, the one arm portion and the other arm portion are each provided to be movable relative to the guide rod, The guide rod is provided with the one friction reducing member and the other friction reducing member. Torsion coil spring device.

4. 2. The torsion coil spring device according to claim 1, a length of at least one of the first friction reduction member and the second friction reduction member in the axial direction of the guide rod is set to be longer than a diameter of the spring material and less than half the axial length of the coil portion; Torsion coil spring device.

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