阅读说明：本技术 张紧杆 (Tension rod ) 是由 村椿研次 于 2021-05-06 设计创作，主要内容包括：本发明的目的在于提供一种张紧杆,可在实现零件个数的削减、轻量化的同时,抑制链条移动时的振动、噪音的产生。具体而言,本发明所涉及的张紧杆(100)被构成为,通过螺旋弹簧(130)的弹力向链条CH侧对转动自如地支撑在安装面上的杆本体(110)进行转动加力,螺旋弹簧(130)具有：按压腕部(132),从卷绕部(131)的一端延伸出,并与杆本体(110)接触；及支撑腕部(133),从卷绕部(131)的另一端延伸出,并被支撑在安装面上,杆本体(110)为具备被卡合部(125)的构成,所述被卡合部(125)被形成为,将螺旋弹簧(130)的支撑腕部(133)弹性变形而钩住,并通过螺旋弹簧(130)的复原弹性,将支撑腕部(133)可装拆地卡合。(The invention aims to provide a tension rod, which can reduce the number of parts and weight and inhibit the generation of vibration and noise when a chain moves. Specifically, the tension rod (100) according to the present invention is configured such that a rod main body (110) rotatably supported on a mounting surface is rotationally urged toward a chain CH by an elastic force of a coil spring (130), and the coil spring (130) includes: a pressing arm (132) extending from one end of the winding part (131) and contacting the lever body (110); and a support arm (133) extending from the other end of the winding part (131) and supported on the mounting surface, wherein the lever body (110) is configured to include an engaged part (125), and the engaged part (125) is formed to elastically deform and hook the support arm (133) of the coil spring (130) and detachably engage the support arm (133) by the restoring elasticity of the coil spring (130).)

1. A tension rod is provided with: a rod body having a guide block surface for slidably guiding the chain formed along the longitudinal direction, and a base end portion rotatably supported on the mounting surface; and a coil spring interposed between the lever body and the mounting surface, and pressing the guide shoe toward the chain side,

the coil spring has: a winding portion virtually embedded in a boss portion provided on the rod body; a pressing wrist portion extending from one end of the winding portion and contacting the rod body; and a support arm portion extending from the other end of the winding portion and supported on the mounting surface,

the rod body has an engaged portion which detachably engages with the support arm portion to hold the coil spring in a compressed state,

the engaged portion is formed to elastically deform and hook the support arm portion, and to engage the support arm portion by the restoring elasticity of the coil spring.

2. The tension rod of claim 1,

the engaged portion is provided on the tip side of the center position in the longitudinal direction of the lever main body or the center position of gravity of the lever main body,

the support arm portion has an engagement arm portion extending from a support portion supported on the mounting surface toward the engaged portion.

3. The tension rod of claim 2,

the locking arm portion has a hook portion formed at a distal end thereof so as to extend in a winding axis direction of the winding portion and engaged with the engaged portion,

the engaged portion is formed to have a wide width in the longitudinal direction of the hook portion.

4. The tension rod according to claim 2 or 3,

the engaged portion is provided so as to protrude from the outer surface of the peripheral wall portion of the lever body such that the distal end portion is positioned on a rotation locus drawn by the rotation of the support arm portion at the distal end of the locking arm portion.

Technical Field

The present invention relates to a tension bar for slidably guiding a moving chain, and more particularly, to a tension bar for a chain, which slidably guides a chain by pressing a guide block surface of a bar body toward the chain side by an elastic force of a torsion coil spring.

Background

Conventionally, in a chain transmission device used for driving an auxiliary device of an automobile engine or the like, as a tension lever for preventing vibration of a moving chain by removing slack of the chain, there is known a tension lever including: a lever body which is swingably mounted on a mounting surface of an engine block or the like and has a guide block surface for slidably guiding a chain; and a torsion coil spring interposed between the lever body and the attachment surface, and pressing the guide shoe toward the chain (see, for example, patent document 1).

The wound portion of the torsion coil spring of the tension lever is loosely fitted to the boss outer peripheral surface of a boss portion formed to protrude from a base plate portion of the lever body toward the attachment surface side, a pressing arm portion extending from one end of the wound portion is in contact with the lever body, and a distal end portion of a support arm portion extending from the other end of the wound portion is attached to the attachment surface so as to be inserted into a spring holding hole formed in the attachment surface. In such a tension rod, the torsion coil spring is twisted by receiving a load from the chain, and therefore a reaction force corresponding to the amount of torsion (the amount of change in the angle of pressing the wrist portion) can be obtained.

In such a tension rod, the distal end portion of the support arm portion extending from the other end of the winding portion is locked by, for example, a stopper member attached to the rod main body in a state before the tension rod is attached to the attachment surface. In the tension lever described in patent document 1, in consideration of ease of mounting the tension lever to the engine, a stopper pin mounting portion having a pin engaging hole into which a stopper member, i.e., a pin member is inserted is formed to protrude outward from an arc-shaped peripheral wall portion defining a space for accommodating a torsion coil spring winding portion in a lever body.

Patent document

Patent document 1: japanese patent laid-open publication No. 2009-108909

Disclosure of Invention

However, in the structure in which the coil spring is locked by the stopper pin, since there is a gap between the stopper pin and the pin insertion hole, there is a possibility that the support arm portion moves so as to be displaced in the axial direction along the stopper pin when the tension rod is transported, shipped, or the like, and the stopper pin is locked to the support arm portion, and the locking operation to the mounting surface is not smoothly performed.

The tension rod disclosed in patent document 1 is configured such that a stopper pin mounting portion is formed in an arcuate peripheral wall portion that defines a space in the rod body in which a coil spring winding portion is housed. Therefore, in a state where the support arm portion is locked by the pin, the coil spring is in a state of large elastic deformation, and there is a possibility that deformation of the lever body itself occurs with time due to stress acting on the lever body.

Further, since the backward movement of the tension rod is not considered, there is a problem that the chain is likely to vibrate or shake when an excessive tension of the chain is generated during use.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a tension rod that can reduce the number of components and weight and can suppress the generation of vibration and noise when a chain moves.

The present invention is a tension rod, including: a rod body having a guide block surface for slidably guiding the chain formed along the longitudinal direction, and a base end portion rotatably supported on the mounting surface; and a coil spring interposed between the lever body and the attachment surface and pressing the guide shoe toward the chain, wherein the coil spring includes: a winding portion virtually embedded in a boss portion provided on the rod body; a pressing wrist portion extending from one end of the winding portion and contacting the rod body; and a support arm portion extending from the other end of the winding portion and supported on the mounting surface, wherein the lever body has an engaged portion that detachably engages with the support arm portion and holds the coil spring in a compressed state, and the engaged portion is formed to elastically deform and hook the support arm portion and to engage with the support arm portion by a restoring elasticity of the coil spring.

According to the tension rod of claim 1, since the support arm portion of the coil spring is engaged with the engaged portion integrally formed in the rod body by the elasticity of the coil spring itself, a stopper member such as a stopper pin is not required, and therefore the number of parts can be reduced and the weight can be reduced. Further, the support arm portion is configured not to become loose with respect to the engaged portion, and the support arm portion is prevented from coming out of engagement with the engaged portion during transportation or shipment of the tension rod, and the support arm portion of the coil spring is elastically deformed, so that the engagement of the support arm portion with respect to the engaged portion can be easily released, and the mounting to the engine can be smoothly performed.

According to the configuration of claim 2, since the amount of bending of the coil spring required to engage the support arm portion with the engaged portion can be reduced, the load applied to the lever main body can be reduced in a state where the support arm portion is engaged with the engaged portion. Therefore, the deformation of the lever main body can be prevented, and the work of mounting the coil spring and the work of attaching the coil spring to the mounting surface can be smoothly performed.

According to the configuration of claim 3, the engagement state between the supporting arm and the engaged portion can be reliably prevented from being unintentionally released.

According to the structure of claim 4, since the clamping wrist part abuts against the clamped part, the tension rod is limited to move in the backward direction relative to the chain, and therefore other mechanisms such as a tensioning device are not needed, and the non-return mechanism capable of realizing large backward movement of the stop rod body can be realized through the single tension rod. Therefore, even when an excessive tension of the chain occurs during use, the generation of noise and vibration due to the vibration of the chain can be suppressed.

Drawings

Fig. 1 is a view showing an example of a usage form of a tension rod according to an embodiment of the present invention.

Fig. 2 is a perspective view of the tension rod as viewed from the mounting surface side.

Fig. 3 is a plan view showing the structure of the tension rod, as viewed from the side opposite to the mounting surface.

Description of the symbols

100-tension rod; 110-a rod body; 111 a-arc-shaped peripheral wall portion; 111 b-one end side peripheral wall portion; 111 c-chain side peripheral wall portion; 111 d-opposite side peripheral wall portion of the chain; 111 e-the other end side peripheral wall portion; 112 a-a stiffener portion; 112 b-a stiffener portion; 113-a partition wall portion; 114-a cut-out portion; 115-a rod side wall portion; 116-an axial hole; 120-a boss portion; 121-a restraining protrusion; 122-spring locking flange part; 123-wall part for forming contact part; 124-inner wall surface; 125-engaged portion; 130-a coil spring; 131-a winding section; 132-pressing the wrist; 132 a-a tip portion; 133-support wrist; 134-rotating wrist; 135-a bend; 136-a clamping wrist; 137-hook portion; CH-chain; an H-coil spring housing; pa-pivot; s-a guide block surface; SP 1-drive side sprocket; SP 2-passive side sprocket; w-support wall portions.

Detailed Description

The tension rod according to one embodiment of the present invention will be described below with reference to the drawings.

As shown in fig. 1, the tension rod 100 slidably guides the chain CH wound between the driving side sprocket SP1 attached to the crankshaft and the driven side sprocket SP2 attached to the auxiliary device shaft so as to appropriately maintain the chain tension.

The tension rod 100 includes: a lever body 110 having a guide surface S for slidably guiding the chain CH along a longitudinal direction, a base end portion of which is rotatably supported by a pivot Pa protruding from an engine block (not shown) or the like; and a coil spring 130 interposed between the lever body 110 and the attachment surface, and pressing the guide surface S toward the chain CH side.

Here, the lever body 110 is formed of, for example, synthetic resin, and the torsion coil spring 130 is formed of, for example, metal.

As shown in fig. 2 and 3, the lever main body 110 includes a lever peripheral wall portion formed to have a substantially hook-jade shape in a plan view as viewed from the axial direction (the direction in which the pivot Pa extends).

The rod peripheral wall portion has: an arc-shaped peripheral wall portion 111a having a shape along the circumference of a concentric circle with the pivot Pa as the center; a substantially flat plate-like one end side peripheral wall portion 111b that is continuous with one end of the arc-like peripheral wall portion 111a and extends toward the chain CH side; a chain-side peripheral wall portion 111c having a shape along an arc protruding toward the chain CH side, one end of which is smoothly continuous with the other end of the one-end peripheral wall portion 111b and extends toward the tip end side; a substantially flat plate-like chain opposite side peripheral wall portion 111d having one end smoothly connected to the other end of the arc-like peripheral wall portion 111a, facing the chain side peripheral wall portion 111c, and extending toward the base end side; and a second end side peripheral wall portion 111e that is smoothly continuous with the respective second ends of the chain side peripheral wall portion 111c and the opposite chain side peripheral wall portion 111d and has an arc shape, and an outer surface of the chain side peripheral wall portion 111c facing the chain CH is configured as a guide surface S that slidably guides the chain CH.

The bead portion 112a provided between the chain side peripheral wall portion 111c and the opposite chain side peripheral wall portion 111d divides a space surrounded by the rod peripheral wall portion into 2 space portions in the longitudinal direction, and the coil spring housing portion H is formed by the space portion located on the base end side. The space on the distal end side is divided by the partition wall 113 in the axial direction (the direction in which the pivot Pa extends), and bead portions 112b extending parallel to the bead portions 112a are provided between the chain side peripheral wall 111c and the chain opposite side peripheral wall 111d in each of the space portions on the mounting surface side and on the opposite side to the mounting surface.

By forming the lever main body 110 in such a manner, the lever main body 110 can be made to have a structure that can sufficiently withstand torsion while achieving weight reduction.

In a portion of the lever peripheral wall portion defining the coil spring housing portion H, a lever side wall portion 115 covering the coil spring housing portion H is continuously provided on an end surface opposite to the mounting surface.

A shaft hole 116 (see fig. 3) into which the pivot Pa is inserted is formed in the lever-side wall portion 115. Further, a cylindrical boss portion 120 protruding from the peripheral edge of the shaft hole 116 toward the mounting surface side is integrally formed on the lever-side wall portion 115, and the lever body 110 is rotatably (swingably) supported on the mounting surface by inserting the pivot shaft Pa into the boss portion 120.

The end surface of the boss portion 120 on the side of the mounting surface protrudes slightly further toward the mounting surface than the end surface of the rod peripheral wall portion, so that the portion other than the end surface of the boss portion 120 on the side of the mounting surface is prevented from coming into contact with the mounting surface, and smooth rotation (oscillation) of the rod main body 110 about the pivot Pa is ensured.

The restricting protrusion 121 for restricting the movement of the coil spring 130 toward the mounting surface side is formed on the mounting surface side end portion on the outer peripheral surface of the boss portion 120, so that the coil spring 130 can be prevented from coming off the lever body 110 in a state before the tension lever 100 is mounted on the mounting surface, and the coil spring 130 can be prevented from interfering with the mounting surface in a state where the tension lever 100 is mounted on the mounting surface.

The coil spring 130 includes a winding portion 131, a pressing arm portion 132 linearly extending from one end of the winding portion 131 on the rod side wall portion 115 side, and a support arm portion 133 extending from the other end of the winding portion 131 on the attachment surface side.

The winding portion 131 is disposed in a state of being virtually fitted to the outer peripheral surface of the boss portion 120 in the coil spring housing portion H, that is, in a state of having a gap between the winding portion 131 and the outer peripheral surface of the boss portion 120.

The pressing arm 132 is disposed such that the distal end 132a thereof abuts against the inner surface of the chain-side peripheral wall 111 c. The distal end portion 132a of the pressing arm portion 132 is bent so as to extend toward the winding shaft direction attachment surface side of the winding portion 131.

The pressing arm portion 132 is locked to the spring locking flange portion 122 provided to protrude from the inner surface of the chain-side peripheral wall portion 111c, and thus a proper contact state of the distal end portion 132a of the pressing arm portion 132 with respect to the inner surface of the chain-side peripheral wall portion 111c can be ensured.

The support wrist 133 has: a rotation arm 134 that is led out to the outside of the lever body 110 through a notch 114 formed in an end surface on the mounting surface side of the arcuate peripheral wall portion 111a, and that linearly extends; and a locking arm portion 136 connected to the tip end of the rotation arm portion 134 via a bent portion 135 constituting a support portion supported on the mounting surface and extending toward the engaged portion 125 formed on the lever main body 110.

The locking arm 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 perpendicular to the rotation arm portion 134.

The locking arm 136 has a hook 137 at the tip thereof, which engages with the engaged portion 125 formed in the lever main body 110. In the present embodiment, the hook portion 137 is formed in an L shape by bending the distal end portion of the locking arm portion 136 extending linearly to extend toward the outer surface side (the side opposite to the attachment surface) in the winding axis direction of the winding portion 131.

As shown in fig. 1, in a state where the tension lever 100 is attached to the attachment surface, since the bent portion 135 is supported by being in contact with the support wall portion W on the attachment surface, the lever body 110 can be urged to rotate toward the chain CH side about the pivot shaft Pa by the elastic force of the coil spring 130.

As shown in fig. 2, in the tension rod 100 of the present embodiment, an abutment portion forming wall portion 123 is formed on the inner surface of the chain side peripheral wall portion 111c, and the abutment portion forming wall portion 123 abuts against the pressing arm portion 132 when the pressing arm portion 132 is deflected in a convex manner toward the chain side peripheral wall portion 111c side by a load of a certain magnitude or more from the chain CH.

The inner wall surface 124 of the contact portion forming wall portion 123 facing the pressing arm portion 132 is configured such that the inner wall surface 124 is separated from the circumferential surface of the pressing arm portion 132 in a state where the tension rod 100 is attached to the attachment surface, and when a load of a predetermined amount or more is applied from the chain CH, the contact range between the pressing arm portion 132 and the contact portion forming wall portion 123 is gradually expanded. In the present embodiment, the inner wall surface 124 of the contact portion forming wall portion 123 is a flat surface.

With this configuration, when a load of a magnitude equal to or larger than a certain magnitude is applied from the chain CH, the load from the chain CH is shared, and therefore, the spring load of the coil spring 130 can be increased, whereby the chain CH can be prevented from rattling at the time of engine start, and an appropriate reaction force can be exerted even against a change in tension accompanying a rapid change in chain behavior.

As described above, in the state before the tension lever 100 is attached to the attachment surface, as shown by the broken line in fig. 2, the support arm 133 of the coil spring 130 is engaged with the engaged portion 125, and the coil spring 130 is held in a compressed state.

The engaged portion 125 is projected in a state inclined toward the distal end side in the longitudinal direction from the outer surface of the opposite-chain-side peripheral wall portion 111d so as to hook the hook portion 137 by elastic deformation of the support arm portion 133 and engage the hook portion 137 by the restoring elasticity of the coil spring 130.

The engaged portion 125 in the present embodiment is formed to have a wide width in the longitudinal direction of the hook portion 137 of the coil spring 130, and a distal end portion is formed in an arc shape so as to form a guide surface for the locking arm portion 136. With such a configuration, while the support arm 133 is structurally easily engaged with the engaged portion 125, the engagement state between the support arm 133 and the engaged portion 125 can be reliably prevented from being accidentally released.

The engaged portion 125 is provided at a position closer to the distal end side than the center position in the longitudinal direction of the lever main body 110 or the center of gravity position of the lever main body 110. By providing the engaged portion 125 at such a position, the load applied to the lever body 110 by the coil spring 130 can be reduced in a state before the tension lever 100 is attached to the attachment surface. Therefore, the lever main body 110 can be reliably prevented from being deformed such as twisted due to the spring load of the coil spring 130.

In the present embodiment, as shown in fig. 3, the distal end portion of the engaged portion 125 is positioned on the rotation locus drawn by the rotation of the support arm portion 133 at the distal end of the locking arm portion 136. Thus, since the movement of the tension rod 100 in the backward direction with respect to the chain CH is restricted by the engagement of the engagement arm portion 136 with the engaged portion 125, a check mechanism capable of checking the large backward movement of the check rod body 110 can be realized by the tension rod 100 alone without using another mechanism such as a tensioner.

In the tension rod 100 of the present embodiment, the hook portion 137 can move to the front end surface side in the longitudinal direction beyond the engaged portion 125 by elastically deforming the support arm portion 133, and then the hook portion 137 can be engaged (locked) with the engaged portion 125 by the restoring force of the coil spring 130. On the other hand, by elastically deforming the supporting arm portions 133, the hook portions 137 can be caused to pass over the engaged portions 125, and the engaged state between the supporting arm portions 133 and the engaged portions 125 can be released.

Although one embodiment of the present invention has been described above in detail, the present invention is not limited to the above embodiment, and various design changes may be made without departing from the scope of the invention described in the claims.

For example, any configuration may be adopted as long as the support arm portion of the coil spring and the engaged portion of the lever main body are configured such that the support arm portion is elastically deformed to be hooked on the engaged portion and the support arm portion and the engaged portion are engaged with each other by the restoring elasticity of the coil spring.

The shape of the support arm portion is not particularly limited, and may be appropriately changed according to the purpose in relation to the formation position of the engaged portion in the lever main body. The support arm portion may be curved in an arc shape so as to protrude outward, for example. In the above-described embodiment, the support arm portion of the coil spring is configured to have the locking arm portion, but the locking arm portion may not be configured, and the locking arm portion may be configured to extend linearly and not have the hook portion at the distal end.