tensioning lever

Abstract

The present application aims to provide a tension rod which can reduce the number of parts, reduce the weight, and suppress the generation of vibration and noise when the chain moves. Specifically, the tension rod (100) of the present application is configured to apply rotational force to a rod body (110) rotatably supported on a mounting surface by the elastic force of a coil spring (130) on the chain CH side, the coil spring (130) has a pressing wrist portion (132) extending from one end of a winding portion (131) and in contact with the rod body (110), and a supporting wrist portion (133) extending from the other end of the winding portion (131) and supported on the mounting surface, and the rod body (110) is configured to have an engaged portion (125) formed to elastically deform the supporting wrist portion (133) of the coil spring (130) to hook and detachably engage the supporting wrist portion (133) by the restoring elasticity of the coil spring (130).

Description

TECHNICAL FIELD

[0001] The present application relates to a tension rod for slide guiding a chain, and particularly to a tension rod for chain, which slide guides a chain by pressing a guide block surface of a rod body to a chain side using the elastic force of a torsion coil spring. BACKGROUND

[0002] In the past, in a chain transmission device for an auxiliary equipment drive of an automobile engine or the like, as a tension rod for eliminating slack of a chain to prevent vibration of a chain in movement, a tension rod has been known, which has a rod body that is swingably mounted to a mounting surface of an engine unit or the like and has a guide block surface that slide guides a chain, and a torsion coil spring that is interposed between the rod body and the mounting surface and presses the guide block surface to the chain side (for example, refer to Patent Document 1).

[0003] The winding portion of the torsion coil spring of such a tension rod is loosely fitted on the outer peripheral surface of a boss portion that is formed so as to protrude from a base plate portion of the rod body toward the mounting surface side, a pressing arm portion that extends from one end of the winding portion is in contact with the rod body, and a tip end portion of a support arm portion that extends from the other end of the winding portion is mounted to the mounting surface in a manner of being inserted into a spring holding hole formed in the mounting surface. In such a tension rod, the torsion coil spring is twisted due to a load from the chain, and thus a reaction force corresponding to the amount of twist (the amount of change in the angle of the pressing arm portion) is obtained.

[0004] In such a tension rod, the tip end portion of the support arm portion that extends from the other end of the winding portion is, for example, caught by a stop member mounted on the rod body in a state before the tension rod is mounted to the mounting surface. In the tension rod described in Patent Document 1, in consideration of the ease of mounting the tension rod to the engine, a stop pin mounting portion is formed so as to protrude outward on an arc-shaped peripheral wall portion that defines a space for housing the winding portion of the torsion coil spring on the rod body, and the stop pin mounting portion has a pin catching hole into which a pin member that is the stop member is inserted.

[0005] PATENT DOCUMENT

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2009-108909 SUMMARY

[0007] However, in the structure in which the coil spring is caught by the stop pin, since there is a gap between the stop pin and the pin insertion hole, it is possible that the support arm portion moves in a manner of being offset in the axial direction along the stop pin at the time of shipping or the like of the tension rod, and as a result, the catching of the stop pin with respect to the support arm portion is released, and further, it is difficult to smoothly perform the mounting work to the mounting surface.

[0008] Further, the tension rod described in Patent Literature 1 is configured such that a stopper pin mounting portion is formed on an arc-shaped peripheral wall portion that defines a space in which a coil portion of a coil spring is accommodated in the rod body. Therefore, in a state in which the support arm portion is locked by the pin, the coil spring is in a state of a large elastic deformation, and a deformation of the rod body itself can occur over time due to stress acting on the rod body.

[0009] Further, since the retreat of the tension rod is not taken into consideration, there is a problem that, in use, when excessive tension of the chain is generated, vibration and shaking of the chain are easily generated.

[0010] The present application is an application that solves such a problem, and the technical problem to be solved is to provide a tension rod that can suppress generation of vibration and noise when the chain moves while achieving reduction in the number of parts and weight reduction.

[0011] The present application is a tension rod including a rod body having a guide surface that guides a chain in sliding along a longitudinal direction, a base end portion rotatably supported on a mounting surface, and a coil spring interposed between the rod body and the mounting surface, which presses the guide surface toward the chain, and solves the problem by including a coil portion that is loosely fitted to a boss portion provided on the rod body, a pressing arm portion that extends from one end of the coil portion and contacts the rod body, and a support arm portion that extends from the other end of the coil portion and is supported on the mounting surface, the rod body having an engaged portion that detachably engages the support arm portion and holds the coil spring in a compressed state, the engaged portion being formed to elastically deform the support arm portion to hook the support arm portion and engage the support arm portion by elastic recovery of the coil spring, the engaged portion being provided on a top end side more than a longitudinal direction center of the rod body or a center of gravity of the rod body, the support arm portion having a rotation arm portion that is guided to the outside of the rod body and extends linearly, and a locking arm portion that is connected to a top end of the rotation arm portion via a bent portion that constitutes a support portion supported on the mounting surface, the locking arm portion being formed to extend toward the engaged portion along a rotation direction of the rotation arm portion in plan view in a winding axis direction of the coil portion, the locking arm portion being engaged with the engaged portion in a state in which the bent portion is separated from the engaged portion in the rotation direction of the rotation arm portion.

[0012] According to the tension rod of the present technical solution 1, since the support wrist of the coil spring is engaged with the engaged portion integrally formed on the rod body by the elasticity of the coil spring itself, no stopper member such as a stop pin is needed, thus the number of parts can be reduced, and the weight can be reduced. Moreover, the support wrist cannot be loosened relative to the engaged portion, and the engagement of the support wrist relative to the engaged portion can be prevented from being released during the transportation of the tension rod, during the delivery, and the like, and at the same time, the engagement of the support wrist relative to the engaged portion can be easily released by elastically deforming the support wrist of the coil spring, thus the installation relative to the engine can be smoothly performed. In addition, since the bending amount of the coil spring required for engaging the support wrist with the engaged portion can be reduced, the load applied to the rod body can be reduced in the state that the support wrist is engaged with the engaged portion. Thus, the deformation of the rod body can be prevented, and the loading work of the coil spring and the installation work relative to the installation surface can be smoothly performed.

[0013] According to the present technical solution 2, the engagement state of the support wrist with the engaged portion can be reliably prevented from being released by accident.

[0014] According to the present technical solution 3, since the movement of the tension rod in the backward direction relative to the chain is limited by the abutment of the engaged portion with the support wrist, the reverse stop mechanism that can reliably prevent the rod body from greatly retreating can be realized by the tension rod alone without using other mechanisms such as a tension device. Thus, even during use, when excessive tension of the chain is generated, the generation of noise and vibration due to the shaking of the chain can be suppressed. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a view showing one example of the use mode of the tension rod according to one embodiment of the present application.

[0016] Figure 2 is a perspective view showing the configuration of the tension rod, viewed from the installation surface side.

[0017] Figure 3 is a plan view showing the configuration of the tension rod, viewed from the side opposite to the installation surface.

[0018] SYMBOL EXPLANATION

[0019] 100 - tension rod; 110 - rod body; 111a - arc-shaped peripheral wall portion; 111b - one end side peripheral wall portion; 111c - chain side peripheral wall portion; 111d - chain opposite side peripheral wall portion; 111e - other end side peripheral wall portion; 112a - reinforcing rib portion; 112b - reinforcing rib portion; 113 - partition wall portion; 114 - cutout portion; 115 - rod side wall portion; 116 - shaft hole; 120 - shaft sleeve portion; 121 - restriction protrusion portion; 122 - spring locking flange portion; 123 - abutment portion forming wall portion; 124 - inner wall surface; 125 - engaged portion; 130 - coil spring; 131 - winding portion; 132 - pressing wrist portion; 132a - tip end portion; 133 - support wrist portion; 134 - turning wrist portion; 135 - bent portion; 136 - locking wrist portion; 137 - hook portion; CH - chain; H - coil spring housing portion; Pa - pivot; S - guide block surface; SP1 - drive side sprocket; SP2 - passive side sprocket; W - support wall portion. DETAILED DESCRIPTION

[0020] Hereinafter, a tension rod according to one embodiment of the present application will be described based on the drawings.

[0021] As shown in Figure 1 , the tension rod 100 slide guides a chain CH wound between a drive side sprocket SP1 attached to a crankshaft and a passive side sprocket SP2 attached to an auxiliary equipment shaft, so as to appropriately maintain chain tension.

[0022] The tension rod 100 has a rod body 110 formed in an elongated shape along a longitudinal direction to slide guide the chain CH, a base end portion rotatably supported on a pivot Pa protruding from an engine block (not shown) or the like, and a coil spring 130 interposed between the rod body 110 and a mounting surface to press the guide block surface S toward the chain CH.

[0023] Here, the rod body 110 is formed of synthetic resin or the like, for example, and the torsion coil spring 130 is formed of metal or the like, for example.

[0024] As shown in Figure 2 and Figure 3 , the rod body 110 has a rod peripheral wall portion formed in a substantially hook-shaped manner in plan view observed in an axial direction (a direction in which the pivot Pa extends).

[0025] The rod peripheral wall portion has: an arc-shaped peripheral wall portion 111a having a shape along a circumference of a concentric circle centered on the pivot Pa; a substantially flat one-end-side peripheral wall portion 111b connected to one end of the arc-shaped peripheral wall portion 111a and extending toward the chain CH side; a chain-side peripheral wall portion 111c having a shape along a circular arc projecting toward the chain CH side, one end of which is smoothly connected to the other end of the one-end-side peripheral wall portion 111b and extends toward the tip end side; a substantially flat chain-opposite-side peripheral wall portion 111d whose one end is smoothly connected to the other end of the arc-shaped peripheral wall portion 111a, opposite the chain-side peripheral wall portion 111c, and extends toward the base end side; and another-end-side peripheral wall portion 111e smoothly connected to the other ends of the chain-side peripheral wall portion 111c and the chain-opposite-side peripheral wall portion 111d and having a circular arc shape, and an outer surface of the chain-side peripheral wall portion 111c opposite the chain CH is configured as a guide surface S that guides sliding of the chain CH.

[0026] The space surrounded by the rod peripheral wall portion is divided into two space portions in the longitudinal direction by a reinforcing rib portion 112a provided between the chain-side peripheral wall portion 111c and the chain-opposite-side peripheral wall portion 111d, and a helical spring housing portion H is formed by the space portion on the base end side. The space portion on the tip end side is divided in the axial direction (the direction in which the pivot Pa extends) by a partition wall portion 113, and between the chain-side peripheral wall portion 111c and the chain-opposite-side peripheral wall portion 111d in each of the space portions on the mounting surface side and the side opposite the mounting surface, a reinforcing rib portion 112b is provided that extends parallel to the reinforcing rib portion 112a.

[0027] By forming the rod body 110 in this manner, it is possible to achieve a structure in which the rod body 110 can sufficiently withstand torsion while achieving weight reduction.

[0028] In the portion of the rod peripheral wall portion that defines the helical spring housing portion H, a rod-side wall portion 115 that covers the helical spring housing portion H is continuously provided on the end surface on the side opposite the mounting surface.

[0029] On the rod-side wall portion 115, a shaft hole 116 (see FIG. 2) into which the pivot Pa is inserted is formed. Figure 3 In addition, on the rod-side wall portion 115, a cylindrical shaft sleeve portion 120 that protrudes from the periphery of the shaft hole 116 toward the mounting surface side is integrally formed, and by inserting the pivot Pa into the shaft sleeve portion 120, the rod body 110 is rotatably (swingably) supported on the mounting surface.

[0030] The mounting surface side end surface of the shaft sleeve portion 120 is formed so as to slightly protrude toward the mounting surface side more than the end surface of the rod peripheral wall portion, whereby it is possible to avoid contact between the portion of the shaft sleeve portion 120 other than the mounting surface side end surface and the mounting surface, and it is possible to ensure smooth rotation (swinging) of the rod body 110 centered on the pivot Pa.

[0031] On the outer peripheral surface of the shaft sleeve portion 120, a restriction protrusion portion 121 is formed on the end portion on the mounting surface side, which restricts the movement of the coil spring 130 toward the mounting surface side. Thus, in a state before the tension rod 100 is mounted to the mounting surface, the coil spring 130 can be prevented from coming off the rod body 110, and in a state where the tension rod 100 is mounted to the mounting surface, the coil spring 130 can be prevented from interfering with the mounting surface.

[0032] The coil spring 130 has a winding portion 131, a pressing wrist portion 132 extending linearly from one end of the winding portion 131 on the rod side wall portion 115 side, and a supporting wrist portion 133 extending from the other end of the winding portion 131 on the mounting surface side.

[0033] The winding portion 131 is configured to be virtually embedded in the outer peripheral surface of the shaft sleeve portion 120 in the coil spring housing portion H, that is, in a state where a gap is present between the winding portion 131 and the outer peripheral surface of the shaft sleeve portion 120.

[0034] The pressing wrist portion 132 is configured such that the top end portion 132a thereof abuts against the inner surface of the chain side peripheral wall portion 111c. The top end portion 132a of the pressing wrist portion 132 is bent so as to extend toward the mounting surface side in the winding axis direction of the winding portion 131.

[0035] The pressing wrist portion 132 is caught in the spring catching flange portion 122 provided to protrude from the inner surface of the chain side peripheral wall portion 111c, and thus, an appropriate abutting state of the top end portion 132a of the pressing wrist portion 132 against the inner surface of the chain side peripheral wall portion 111c can be ensured.

[0036] The supporting wrist portion 133 has a rotating wrist portion 134 guided to the outside of the rod body 110 via the cutout portion 114 formed on the end surface of the arc-shaped peripheral wall portion 111a on the mounting surface side and extending linearly, and a catching wrist portion 136 connected to the top end of the rotating wrist portion 134 via the bent portion 135 constituting a supporting portion supported on the mounting surface and extending toward the engaged portion 125 formed on the rod body 110.

[0037] The catching wrist portion 136 is configured to be bent toward the winding portion 131 side in a plane perpendicular to the winding axis of the winding portion 131 and to extend in a direction orthogonal to the rotating wrist portion 134.

[0038] Further, the catching wrist portion 136 has a hook portion 137 on the top end thereof, which engages with the engaged portion 125 formed on the rod body 110. In the present embodiment, the hook portion 137 is formed by bending the top end portion of the linearly extending catching wrist portion 136 so as to extend toward the outside of the winding axis direction of the winding portion 131 (the side opposite to the mounting surface), thereby forming an L shape.

[0039] As Figure 1As shown, in a state where the tension rod 100 is installed to the installation surface, the bent portion 135 is supported by abutting against the support wall portion W on the installation surface, so the lever body 110 is rotated to the chain CH side about the pivot Pa by the elastic force of the coil spring 130.

[0040] On the tension rod 100 of the present embodiment, as shown in Figure 2 On the inner face of the chain side peripheral wall portion 111c, an abutment portion forming wall portion 123 is formed, which abuts against the pressing wrist portion 132 when the pressing wrist portion 132 is pressed toward the chain side peripheral wall portion 111c side in a convex manner when a load of a certain magnitude or more is received from the chain CH.

[0041] The inner wall face 124 of the abutment portion forming wall portion 123 opposite the pressing wrist portion 132 is configured so that, in a state where the tension rod 100 is installed to the installation surface, the inner wall face 124 is separated from the peripheral face of the pressing wrist portion 132, and when a load of a certain magnitude or more is received from the chain CH, the abutment range of the pressing wrist portion 132 against the abutment portion forming wall portion 123 gradually expands. In the present embodiment, the inner wall face 124 of the abutment portion forming wall portion 123 is a flat face.

[0042] By forming such a configuration, when a load of a certain magnitude or more is received from the chain CH, the load from the chain CH is shared, so the spring load of the coil spring 130 can be increased, and thus the chain CH can be prevented from shaking at the time of engine start, and at the same time, an appropriate reaction force can be exerted against changes in tension accompanying a sudden change in chain behavior.

[0043] As described above, in a state before the tension rod 100 is installed to the installation surface, as shown by the dotted line in Figure 2 , the support wrist portion 133 of the coil spring 130 is engaged with the engaged portion 125, and the coil spring 130 is held in a compressed state.

[0044] The engaged portion 125 is provided so as to be inclined from the outer face of the chain opposite side peripheral wall portion 111d toward the longitudinal direction top end side, so as to hook the hook portion 137 by elastic deformation of the support wrist portion 133, and engage the hook portion 137 by the restoring elasticity of the coil spring 130.

[0045] The engaged portion 125 in the present embodiment is formed so as to be wide in the length direction of the hook portion 137 of the coil spring 130, and the top end portion is formed in a circular arc shape so as to form a guide face of the engaged wrist portion 136. By forming such a configuration, the support wrist portion 133 can be engaged with the engaged portion 125 in structure, and at the same time, the engaged state of the support wrist portion 133 with the engaged portion 125 can be reliably prevented from being released by accident.

[0046] The engaged portion 125 is provided at a position on the top end side of the center position in the longitudinal direction of the rod body 110 or the center of gravity position of the rod body 110. By providing the engaged portion 125 at such a position, the load applied to the rod body 110 by the coil spring 130 can be reduced in a state before the tension rod 100 is installed to the installation surface. Thus, the deformation such as the twist of the rod body 110 due to the spring load of the coil spring 130 can be surely prevented.

[0047] In the present embodiment, as shown in Figure 3 The top end portion of the engaged portion 125 is located on a rotational trajectory traced by the rotation of the support arm portion 133 from the top end of the engagement arm portion 136. Thus, since the movement of the tension rod 100 in the retreat direction with respect to the chain CH is restricted by the abutment of the engagement arm portion 136 and the engaged portion 125, the reverse stop mechanism that surely stops the large retreat of the rod body 110 can be realized by the tension rod 100 alone without using other mechanisms such as a tension device.

[0048] On the tension rod 100 of the present embodiment, the hook portion 137 can be moved to the longitudinal direction top end surface side by elastically deforming the support arm portion 133 to pass over the engaged portion 125, and the hook portion 137 can be engaged (engaged) with the engaged portion 125 by the restoring force of the coil spring 130. On the other hand, the hook portion 137 can be made to pass over the engaged portion 125 by elastically deforming the support arm portion 133, and thus the engaged state of the support arm portion 133 and the engaged portion 125 can be released.

[0049] Although one embodiment of the present application has been described above, the present application is not limited to the above-described embodiment, and various design changes can be made within the scope of the technical idea described in the present application.

[0050] For example, as long as the support arm portion of the coil spring and the engaged portion of the rod body can be configured such that the support arm portion is hooked on the engaged portion by elastically deforming, and the support arm portion and the engaged portion are engaged with each other by the restoring elasticity of the coil spring, any configuration can be used.

[0051] Further, the shape of the support arm portion is not particularly limited, and can be appropriately changed depending on the purpose with respect to the formation position of the engaged portion on the rod body. The support arm portion can be, for example, configured to be curved in an arc shape and extend in a manner of protruding outward. Further, although the support arm portion of the coil spring is configured to have the engagement arm portion in the above-described embodiment, the support arm portion can be configured not to have the engagement arm portion, and the engagement arm portion can be configured to extend in a straight line shape and not to have the hook portion on the top end.

Claims

1. A tension rod comprising: a rod body having a guide surface for slidingly guiding a chain formed along a longitudinal direction, a base end portion rotatably supported on a mounting surface; and a coil spring interposed between the rod body and the mounting surface, pressing the guide surface toward the chain, characterized in that: the coil spring has a winding portion elastically fitted to a boss portion provided on the rod body, a pressing arm portion extending from one end of the winding portion and contacting the rod body, and a supporting arm portion extending from the other end of the winding portion and supported on the mounting surface, the rod body has an engaged portion detachably engaging the supporting arm portion to hold the coil spring in a compressed state, the engaged portion is formed to elastically deform the supporting arm portion to hook the supporting arm portion and engage the supporting arm portion by elastic recovery of the coil spring, the engaged portion is provided on a top end side from a longitudinal direction center of the rod body or a center of gravity of the rod body, the supporting arm portion has a rotating arm portion guided to the outside of the rod body and extending linearly, and a locking arm portion connected to a top end of the rotating arm portion via a bent portion constituting a support portion supported on the mounting surface, the locking arm portion is formed to extend toward the engaged portion along a rotating direction of the rotating arm portion in plan view in a winding axis direction of the winding portion, and the locking arm portion engages the engaged portion in a state where the bent portion is separated from the engaged portion in the rotating direction of the rotating arm portion.

2. The tension rod according to claim 1, characterized in that: the locking arm portion has a hook portion formed on a top end to extend in the winding axis direction of the winding portion and engage the engaged portion, and the engaged portion is formed to have a width wider in a length direction of the hook portion.

3. The tension rod according to claim 1 or 2, characterized in that: the engaged portion is provided to protrude from the outside of a peripheral wall portion of the rod body so that a top end portion is located on a rotating locus traced by the top end of the locking arm portion by rotation of the supporting arm portion. ​ ​ ​ ​ ​ ​ ​ ​ ​

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