Tension rod

Abstract

The object of the present invention is to provide a tension rod which can reduce vibration and noise when a chain moves, and can realize smooth installation in an engine while suppressing deformation of a rod body with a simple structure. Specifically, the tension rod (100) of the present invention comprises: a rod body (110) having a guide block surface formed along the longitudinal direction for slidingly guiding a chain; and a torsion coil spring (120) having a pressing arm (122) abutting against the rod body and a supporting arm (123) supported on the installation surface, the rod body (110) having a stopper member installation portion (130) to which a stopper member (150) is detachably installed, the stopper member (150) locking the supporting arm (123) so as to fix the torsion coil spring (120) in a compressed state, and the stopper member installation portion (130) is configured to be located on the top side of the longitudinal center position CL of the rod body (110) or the center of gravity of the rod body (110).

Description

Technical Field

[0001] The present invention relates to a tension rod for slidingly guiding a moving chain, and more particularly to a tension rod for a chain for slidingly guiding a chain by pressing a guide block surface of a rod body toward the chain side using the elastic force of a torsion coil spring. Background Art

[0002] Conventionally, in a chain transmission device used for driving auxiliary equipment of an automobile engine, a tension rod is known as a tension rod for eliminating chain slack to prevent vibration of the moving chain. The tension rod comprises: a rod body that is swingably mounted on a mounting surface of an engine block, etc., and has a guide block surface for slidingly guiding the chain; and a torsion coil spring that is sandwiched between the rod body and the mounting surface to press the guide block surface toward the chain side (for example, refer to patent documents 1 to patent document 3).

[0003] The winding portion of the torsion coil spring of these tension rods is dummy-fitted on the outer peripheral surface of the sleeve portion formed to protrude from the base plate portion of the rod body toward the mounting surface, the pressing arm portion extending from one end of the winding portion contacts the rod body, and the top end of the supporting arm portion extending from the other end of the winding portion is installed on the mounting surface in a manner of being inserted into a spring holding hole formed on the mounting surface. In this tension rod, the torsion coil spring is twisted due to the load from the chain, so a reaction force corresponding to the twisting amount (angle change amount of the pressing arm portion) can be obtained.

[0004] In this tension rod, before the tension rod is mounted on the mounting surface, for example, the top end of the support arm extending from the other end of the winding portion is locked by a stopper mounted on the rod body. In the tension rod described in Patent Document 1, in consideration of the ease of mounting the tension rod relative to the engine, the stopper pin mounting portion is formed to protrude outward on the arc-shaped peripheral wall portion of the rod body that defines the space for accommodating the winding portion of the torsion coil spring, and the stopper pin mounting portion has a pin locking hole into which the stopper, i.e., the pin member, is inserted.

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2009-108909

[0007] Patent Document 2: Japanese Patent Application Publication No. 2016-160985

[0008] Patent Document 3: Japanese Patent Application Publication No. 2017-115952 Summary of the invention

[0009] Furthermore, in order to suppress the vibration of the chain, it is conceivable to use a spring with a high spring load (a spring corresponding to a high load) as a torsion coil spring on the tension rod.

[0010] However, it is known that in the tension rods described in Patent Documents 1 to 3, when a torsion coil spring with a high spring load is used, deformation of the stopper pin locking hole or deformation of the rod body itself may occur over time. When such deformation occurs, there are problems such as inconvenience in mounting the tension rod, deflection of the guide block surface, or inconvenience in the chain line which is the moving trajectory of the chain.

[0011] The present invention is an invention for solving such a problem. The technical problem to be solved is to provide a tension rod which can reduce vibration and noise when the chain moves and can be smoothly installed into the engine while suppressing deformation of the rod body with a simple structure.

[0012] The present invention is a tensioning rod, comprising: a rod body made of resin, on which a guide block surface for slidingly guiding a chain is formed along the longitudinal direction, and a base end portion is rotatably supported on a mounting surface; and a torsion coil spring, which is sandwiched between the rod body and the mounting surface and presses the guide block surface to the chain side. The problem is solved by the following contents, namely, the torsion coil spring has: a winding portion, which is virtually embedded in a shaft sleeve portion provided on the rod body; a pressing wrist portion, which extends from one end of the winding portion and contacts the rod body; a supporting wrist portion, which extends from the other end of the winding portion and is supported on the mounting surface, the rod body having a stop member mounting portion on which a stop member is detachably mounted, the stop member locks the supporting wrist portion so as to fix the torsion coil spring in a compressed state, and the stop member mounting portion is provided on the top end side than the longitudinal center position of the rod body or the center of gravity position of the rod body.

[0013] According to the tension rod involved in the technical solution 1, since the load of the torsion coil spring applied to the rod body can be reduced in the state where the support arm is locked to the stopper, deformation such as torsion caused by the spring load can be prevented from occurring in the rod body. Therefore, the desired performance of the tension rod can be stably exerted while the installation relative to the engine can be smoothly performed. Therefore, since a spring with a high spring load can be used as the torsion coil spring, an appropriate reaction force can be exerted against the change in tension accompanying the change in chain behavior, thereby suppressing the shaking of the chain.

[0014] Furthermore, the desired effect can be obtained with a simple structure without impairing the following unique effects of the tension rod, that is, the improvement of fuel efficiency due to the absence of oil pressure and the improvement of fuel efficiency due to the small size and light weight.

[0015] According to the structure described in Technical Solution 2, since the load applied to the rod body can be further reduced when the support wrist is locked in the stop part, deformation of the rod body can be effectively prevented. In addition, the torsion coil spring can be smoothly installed and installed relative to the mounting surface.

[0016] According to the structure described in the third embodiment of the present invention, the locked state between the support wrist and the stopper member can be prevented from being accidentally released.

[0017] According to the configuration described in claim 4 , the rod body can be made into a structure that can fully withstand torsion. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a diagram showing an example of a usage form of a tension rod which is one embodiment of the present invention.

[0019] Figure 2 This is a rear side view showing the structure of the tension rod in a state where the stopper member is removed.

[0020] Figure 3 This is a rear perspective view showing the structure of the tension rod in a state where the stopper member is removed.

[0021] Figure 4 It is a rear perspective view showing a state in which the stopper member is locked to the supporting wrist portion.

[0022] Figure 5 It is a rear perspective view showing the structure of a tension rod according to another embodiment of the present invention.

[0023] Figure 6 It is a rear perspective view showing the structure of a tension rod according to still another embodiment of the present invention.

[0024] Explanation of symbols

[0025] 100-tensioning rod; 110-rod body; 111-rod peripheral wall; 111a-arc-shaped peripheral wall; 111b-chain side peripheral wall; 111c-chain opposite side peripheral wall; 112a-central reinforcing rib; 112b-reinforcing rib; 112c-reinforcing rib; 113a-partition wall; 113b-partition wall; 114-cutout; 115-rod side wall; 116-shaft hole; 117-shaft sleeve; 118-limiting protrusion; 119-spring locking flange; 120-torsion coil spring; 121-winding portion; 122-press - Pressing wrist part; 123- supporting wrist part; 124- rotating wrist part; 125- bending part; 126- locking wrist part; 126a- locking wrist part; 126b- locking wrist part; 127- hook part; 127b- hook part; 130- stop member mounting part; 131- pin locking hole; 150- stop member; 151- shaft part; 152- finger hook part; CH- chain; H- torsion coil spring receiving part; Lc- center position of the rod body in the longitudinal direction; Pa- pivot; S- guide block surface; SP1- driving side sprocket; SP2- passive side sprocket; W- supporting wall part. DETAILED DESCRIPTION

[0026] Hereinafter, a tension rod which is one embodiment of the present invention will be described with reference to the drawings.

[0027] like Figure 1 As shown, the tensioning rod 100 is swingably mounted on a pivot Pa protruding from a mounting surface (not shown) of an engine block (not shown) or the like, and slidingly guides a chain CH spanned between a driving side sprocket SP1 mounted on a crankshaft and a passive side sprocket SP2 mounted on an auxiliary equipment shaft, thereby appropriately maintaining the chain tension.

[0028] The tensioning rod 100 comprises: a rod body 110, a guide block surface S for slidingly guiding the chain CH is formed along the longitudinal direction, and the base end portion is rotatably supported on the mounting surface; and a torsion coil spring 120, which is sandwiched between the rod body 110 and the mounting surface and presses the guide block surface S of the rod body 110 toward the chain CH side. Figure 1 As shown, the lever body 110 is biased to rotate toward the chain CH side around the pivot axis Pa by the elastic force of the torsion coil spring 120, and the chain CH is pressed via the guide shoe surface S.

[0029] Here, the rod body 110 is formed of, for example, synthetic resin or the like, and the torsion coil spring 120 is formed of, for example, metal or the like.

[0030] like Figure 2 and Figure 3 As shown, the rod body 110 includes a rod peripheral wall portion 111 formed in a substantially magatama shape in a side view.

[0031] The rod circumferential wall portion 111 includes: an arcuate circumferential wall portion 111a having a shape along a circumference of a concentric circle with the pivot axis Pa as the center; a chain side circumferential wall portion 111b, one end of which is connected to one end of the arcuate circumferential wall portion 111a, and has a shape along an arc convex toward the chain CH side; and a roughly flat-plate-shaped chain opposite side circumferential wall portion 111c, one end of which is smoothly connected to the other end of the arcuate circumferential wall portion 111a, and the other end is smoothly connected to the other end of the chain side circumferential wall portion 111b and extends opposite to the chain side circumferential wall portion 111b, and the outer surface of the chain side circumferential wall portion 111b, which is opposite to the chain CH and extends along the longitudinal direction, constitutes a guide block surface S for slidingly guiding the chain CH.

[0032] The space surrounded by the rod peripheral wall portion 111 is divided into two space portions in the longitudinal direction by the central reinforcing rib portion 112a provided between the chain side peripheral wall portion 111b and the chain opposite side peripheral wall portion 111c. The space portion located on the base end side is further divided by the reinforcing rib portion 112b extending in the longitudinal direction, and the torsion coil spring accommodating portion H is formed by the space portion located on the chain opposite side. The space portion located on the chain CH side is divided in the axial direction by the partition wall portion 113a extending along a plane perpendicular to the direction in which the pivot axis Pa extends.

[0033] On the other hand, the space portion located on the top end side is divided in the axial direction by a partition portion 113b, which extends along a plane perpendicular to the direction in which the pivot axis Pa extends, and in each space portion, a reinforcing rib portion 112c is provided between the chain side peripheral wall portion 111b and the chain opposite side peripheral wall portion 111c.

[0034] By configuring the rod body 110 in such a configuration, it is possible to achieve a structure that is lightweight and can sufficiently withstand torsion.

[0035] In a portion of the rod body 110 that defines the torsion coil spring accommodating portion H, a rod side wall portion 115 that covers the torsion coil spring accommodating portion H is continuously provided on the end surface on the opposite side to the mounting surface.

[0036] The rod side wall portion 115 is provided with an axial hole 116 for inserting the pivot shaft Pa. In addition, the rod side wall portion 115 is integrally provided with a cylindrical shaft sleeve portion 117 protruding from the periphery of the shaft hole 116 toward the mounting surface side, and by inserting the pivot shaft Pa into the shaft sleeve portion 117, the rod body 110 is supported on the mounting surface in a swingable (rotatable) manner.

[0037] The end face of the mounting surface side of the sleeve portion 117 is slightly protruded toward the mounting surface side than the end face of the rod peripheral wall portion 111, thereby preventing the portion other than the end face of the mounting surface side of the sleeve portion 117 from contacting the mounting surface, thereby ensuring smooth shaking (rotation) of the rod body 110 centered on the pivot Pa.

[0038] On the end portion of the outer peripheral surface of the sleeve portion on the mounting surface side, a limiting protrusion 118 is formed to limit the movement of the torsion coil spring 120 toward the mounting surface side. This can prevent the torsion coil spring 120 from escaping from the rod body 110 before the tensioning rod 100 is installed on the mounting surface. At the same time, when the tensioning rod 100 is installed on the mounting surface, the torsion coil spring 120 can be prevented from interfering with the mounting surface.

[0039] The torsion coil spring 120 includes a coil portion 121 , a pressing arm portion 122 extending linearly from one end of the coil portion 121 on the rod side wall portion 115 side, and a supporting arm portion 123 extending from the other end of the coil portion 121 on the mounting surface side.

[0040] The coil portion 121 is disposed in a state of being loosely fitted on the outer peripheral surface of the boss portion 117 in the torsion coil spring accommodation portion H, that is, in a state of having a gap between the coil portion 121 and the outer peripheral surface of the boss portion 117 .

[0041] The pressing arm portion 122 is disposed, for example, so as to be in contact with the inner surface of the reinforcing rib portion 112 b over the entire region in the longitudinal direction thereof. The tip end portion of the pressing arm portion 122 is bent so as to extend in the direction of the spiral axis.

[0042] The top end side portion of the pressing arm 122 is locked to the spring locking flange portion protruding from the inner surface of the reinforcing rib portion 112b toward the torsion coil spring accommodating portion H, thereby ensuring the appropriate abutment state of the pressing arm 122 relative to the inner surface of the reinforcing rib portion 112b.

[0043] The supporting wrist portion 123 includes: a rotating wrist portion 124, which is guided out of the rod body 110 through a cutout portion 114 formed on the arc-shaped peripheral wall portion 111a and extends in a straight line; and a locking wrist portion 126, which is connected to the rotating wrist portion 124 through a curved portion 125 constituting a support portion supported on the mounting surface and extends toward the stopper mounting portion 130 of the rod body 110. In this embodiment, as Figure 1 As shown, when the tension rod 100 is mounted on the mounting surface, the bent portion 125 is supported by being abutted against the support wall portion W on the mounting surface.

[0044] In the present embodiment, the locking arm portion 126 is configured to bend toward the winding portion 121 in a plane perpendicular to the spiral axis and to extend in a direction perpendicular to the rotating arm portion 124 .

[0045] The locking arm 126 has a hook 127 at the tip thereof to be locked to the stopper 150. In the present embodiment, the hook 127 is formed in an L-shape by bending the tip of the locking arm 126 extending linearly to extend parallel to the rotating arm 124.

[0046] As described above, before the tension rod 100 is installed on the installation surface, Figure 4 As shown, the support arm portion 123 of the torsion coil spring 120 is locked to the stopper member 150, so that the torsion coil spring 120 is maintained in a compressed state.

[0047] Furthermore, in the tension rod 100 of the present embodiment, a stopper member mounting portion 130 is provided at a position closer to the tip side than the longitudinal center position Lc of the rod body 110 or the center of gravity position of the rod body 110. Here, in the case where the longitudinal center position of the rod body 110 and the center of gravity position of the rod body 110 are different, the stopper member mounting portion 130 only needs to be provided at a position closer to the tip side than either the longitudinal center position of the rod body 110 or the center of gravity position of the rod body 110, whichever is located on the base end side of the rod body 110.

[0048] The stopper member mounting portion 130 is provided so as to protrude from the anti-chain side peripheral wall portion 111 c and has a pin locking hole 131 extending in the coil axis direction of the torsion coil spring 120 .

[0049] The stopper member 150 of this embodiment is as follows Figure 4 As shown, it is formed by bending a rod-shaped material made of metal or the like, and includes a rod-shaped shaft portion 151 that is detachably inserted into the pin locking hole 131 of the lever body 110 and an annular finger hook portion 152 .

[0050] like Figure 1 As shown, in a state where the tension rod 100 is mounted on a mounting surface, the stopper 150 is removed from the pin locking hole 131 .

[0051] As described above, the tension rod 100 of the present embodiment has the following structure, that is, when the tension rod 100 is mounted on the mounting surface, the support arm portion 123 of the torsion coil spring 120 abuts against the support wall portion W, and has the locking arm portion 126 extending from the bent portion 125 forming a support point and extending toward the stopper mounting portion 130 of the rod body 110. As a result, the stopper mounting portion 130 can be provided at a position closer to the top end side than the longitudinal center position Lc of the rod body 110 or the center of gravity position of the rod body 110. Therefore, since the load of the torsion coil spring 120 applied to the rod body 110 can be reduced before the tension rod 100 is mounted on the mounting surface, it is possible to reliably prevent the rod body 110 from being deformed by torsion or the like due to the spring load of the torsion coil spring 120.

[0052] Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the present invention described in the claims.

[0053] For example, in the above-described embodiment, the support arm portion of the torsion coil spring is configured to have a locking arm portion, but may be configured not to have a locking arm portion.

[0054] In addition, if Figure 5 As shown in FIG. 1 , the locking arm portion 126a may also be configured to have no hook portion at the top, but to extend in a straight line. In addition, the hook portion need not be bent into an L-shaped shape, such as Figure 6 Although in the present embodiment, the hook portion 127a is formed to be curved and extended in an arc shape from the top end of the locking arm portion 126b toward the winding portion side, it can also be formed to be curved and extended in an arc shape from the top end of the locking arm portion 126b toward the top end side of the rod body.

[0055] Furthermore, although the locking arm portion is bent and formed to be orthogonal to the base end portion, the shape of the locking arm portion is not particularly limited, and the relationship between the formation position of the stopper member mounting portion on the rod body can be appropriately changed according to the purpose.

Claims

1. A tensioning rod, comprising: a rod body made of resin, a guide block surface for slidingly guiding a chain formed along the longitudinal direction, a base end portion being rotatably supported on a mounting surface; and a torsion coil spring, sandwiched between the rod body and the mounting surface, pressing the guide block surface toward the chain side, characterized in that: The torsion coil spring comprises: a winding portion, which is virtually embedded in a shaft sleeve portion provided on the rod body; a pressing wrist portion, which extends from one end of the winding portion and contacts the rod body; and a supporting wrist portion, which extends from the other end of the winding portion and is supported on the mounting surface. The rod body has a stopper member mounting portion on which a stopper member is detachably mounted, and the stopper member locks the support wrist portion so as to fix the torsion coil spring in a compressed state. The stopper member mounting portion is disposed on the tip side relative to the longitudinal center position of the rod body or the center of gravity position of the rod body. The supporting wrist portion comprises: a rotating wrist portion extending in a straight line; and a locking wrist portion connected to the rotating wrist portion via a curved portion constituting a supporting portion supported on the mounting surface, and extending toward the stop member mounting portion of the rod body along the rotating direction of the rotating wrist portion, The supporting arm is configured such that, when the locking arm is locked to the stopper, the bent portion is located at a position separated from the stopper mounting portion by a length of the locking arm in the rotation direction of the rotating arm.

2. The tension rod according to claim 1, characterized in that The supporting wrist has a hook portion at the top end thereof which is locked to the stopping member.

3. The tension rod according to claim 1, characterized in that The rod body has a reinforcing rib portion, and the reinforcing rib portion is configured to be contactable by the pressing wrist portion over the entire area in the length direction.

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