JP2022011785A - Chain tensioner and tensioner releasing tool - Google Patents

Abstract

To provide an improved chain tensioner which enables tension release of a timing chain without removing the timing chain from an engine to improve costs and workability during replacement of the timing chain.SOLUTION: A chain tensioner has: a plunger 7 which may press a timing chain 4 in a direction in which the timing chain 4 is stretched; a housing 6 which supports the plunger 7 in a manner that the plunger 7 does not rotate relative to the housing 6 and can move forward and rearward; an operation body 8 which has an axis P along a direction in which the plunger 7 moves forward and rearward, is threadedly engaged with the plunger 7, and rotatably housed in the housing 6 in the threadedly engaged state; and an operation hole 6a formed at the housing 6 so as to rotationally operate the operation body 8 from the outside of the housing 6. The chain tensioner is provided at an engine.SELECTED DRAWING: Figure 3

Description

The present invention relates to a chain tensioner and a tensioner release tool applicable to various engines such as industrial diesel engines and automobile engines.

Some engines have a structure in which a camshaft is driven by winding a chain over the crank gear of the crankshaft and the cam gear of the camshaft, that is, a structure provided with a so-called timing chain. Engines with timing chains are equipped with chain tensioners to prevent the timing chains from loosening.

For example, as shown in Patent Document 1 (see FIG. 1 and the like), a timing chain (13) is wound over a crank gear (9) and a pair of cam gears (5) and (7), and a return thereof is performed. A movable lever member (17) that slides into contact with the outside of the side chain portion (12a) is arranged, and a chain tensioner (19) that acts on the lever member (17) is provided.

Japanese Unexamined Patent Publication No. 2016-38077

To loosen and remove an existing timing chain to replace the timing chain, the work of releasing the tension of the timing chain is first performed. In this case, in the conventional engine, since the chain tensioner is removed in order to release the tension of the timing chain, there is a problem that the gasket is consumed and it is difficult to remove and reattach the chain tensioner.

That is, when the engine is mounted on the bonnet or under the seat, the space around the engine is narrow, so the chain tensioner attached to the engine case such as the cylinder block has poor workability and is difficult to do. There is a face. In addition, since the gasket is sandwiched between the housing of the chain tensioner and the engine case, removing the chain tensioner in most cases requires replacement of the gasket, which is costly. there were.

The object of the present invention has been improved so that the tension of the timing chain can be released without removing it from the engine by further research and ingenuity, and the cost and workability at the time of timing chain replacement can be improved. The point is to provide a chain tensioner. It is also an object of the present invention to provide a tensioner release tool that can easily and conveniently perform the work of releasing the tension of the improved chain tensioner.

The present invention relates to a chain tensioner.
A plunger that can be pressed in the direction of tensioning the timing chain,
A housing that supports the plunger so that it cannot rotate relative to each other and can move in and out.
An operating body that has an axial center along the moving direction of the plunger and is rotatably housed in the housing while being screwed into the plunger.
An operation hole formed in the housing for rotating the operating body from the outside of the housing,
It is characterized in that it is provided in the engine.

The second invention is in the tensioner release tool.
A support cylinder that can be screwed into an operation hole formed in the housing of the chain tensioner, a rotation shaft that is rotatably fitted in the support cylinder, and a rotating portion for rotating and operating the rotation shaft. Have and
At the tip of the rotating shaft, an operating portion that is rotatably housed in the housing and is rotatably engaged with the operated portion of the operating body having the operated portion facing the operation hole is provided. Formed,
By turning the turning portion in the mounted state in which the support cylinder is screwed into the operating hole, the operating body is turned via the rotating shaft in which the operating portion is engaged with the operated portion. It is characterized in that it is configured to be operable.

For other inventions, refer to claims 2 to 4 and claims 6 to 9 in the claims.

According to the chain tensioner of the present invention, the plunger can be moved forward or backward by turning the operating body from the operation hole using a tool or the like. Therefore, the effect of loosening the timing chain by forcibly moving the plunger in and out to release the tension and performing maintenance work such as replacement of the timing chain without removing the chain tensioner from the engine can be obtained.
In addition, since it is not necessary to remove the chain tensioner from the engine, a new gasket is not required, which has the advantage of reducing costs and improving workability.

As a result, it is possible to provide an improved chain tensioner so that the tension of the timing chain can be released without removing it from the engine, and the cost and workability at the time of timing chain replacement can be improved. ..

According to the second tensioner release tool of the present invention, maintenance such as adjustment and release of tension of the timing chain can be easily and conveniently performed without removing the chain tensioner from the engine. Since the tension can be easily and conveniently released by moving the plunger in and out, there is an effect that the preparatory work (chain tensioner function release work) for maintenance work such as timing chain replacement can be made more efficient.

As a result, it is possible to provide a tensioner release tool that is easy and convenient to release the tension without removing the chain tensioner from the engine and is excellent in usability.

Sectional drawing showing structure of tensioner release tool Sectional view showing the structure of the tensioner A cross-sectional view showing an operable state in which the tensioner release tool is attached to the tensioner. Cross section of engine equipped with tensioner

Hereinafter, embodiments of the engine chain tensioner and tensioner release tool according to the present invention will be described with reference to the drawings.

As shown in FIG. 4, an inclined engine E suitable as a driving source for traveling vehicles such as automobiles, agricultural machinery, and construction machinery is shown, 11 is a cylinder block, 12 is a cylinder head, and 13 is a head cover. Reference numeral 14 is an oil pan, and the cylinder block 11 has a crankcase portion 11A and a cylinder portion 11B.

A timing chain (an example of a chain) 4 is wound around a crank gear 1G attached to a crank shaft 1 of a cylinder block 11 and cam gears 2G and 3G attached to each of a pair of camshafts 2 and 3, respectively. There is. A chain slider 5 in contact with the outside of the tensioned portion 4a of the timing chain 4 (outside of the chain winding loop) is supported so as to be swingable around the lower fulcrum Q. A chain tensioner T that presses and urges the chain slider 5 in the tension direction of the timing chain 4 (inward direction of the chain winding loop) is provided by bolting or the like.

The chain tensioner T will be described. As shown in FIGS. 2 and 3, the chain tensioner (tensioner ASSY) T has a plunger 7, an operating body 8, a buffer spring 9, and a torsion coil spring (coil spring) 10 in a housing 6. As shown in FIG. 4, for example, the chain tensioner T is provided in the engine E in a state of penetrating the cylinder portion 11B.

Specifically, it has a plunger 7 that can be pressed in the direction in which the timing chain 4 is stretched, a housing 6 that supports the plunger 7 so as to be relatively non-rotatable and can move in and out, and an axial center P along the moving direction of the plunger 7. The operation body 8 is rotatably housed in the housing 6 while being screwed into the plunger 7, and the operation hole 6a formed in the housing 6 for rotating the operation body 8 from the outside of the housing 6. And, the chain tensioner T is configured.

As shown in FIGS. 2 and 3, the housing 6 is bolted to the side wall portion 11b of the cylinder block 11 (cylinder portion 11B) via the gasket 15 by using the flange portion 6F, and has a cylindrical interior. The space 6S is provided with an operation hole 6a having a diameter smaller than that of the internal space 6S and subsequently opening to the base end surface 6b. An internal screw 6n is formed at the base end of the operation hole 6a. As shown in FIG. 2, the housing 6 may be composed of, for example, a housing body 6A and a housing lid 6B screwed to the tip end side thereof.

As shown in FIGS. 2 and 3, the plunger 7 includes an outer fitting portion 7A having a nut portion 7n extending in the axial center P direction at the center, a slide shaft portion 7B, and a pressing portion 7C, and is a slide shaft. The portion 7B is internally fitted in the insertion hole 6c of the housing 6 (housing lid 6B) so as to be relatively non-rotatable and capable of moving back and forth (reciprocating slide movement) in the axial center P direction. It is preferable that the slide shaft portion 7B and the insertion hole 6c are fitted in a shape such as a square or a D shape that cannot be relatively rotated around the axis P. Further, it is convenient that the pressing portion 7C and the slide shaft portion 7B are detachably screwed together.

As shown in FIGS. 2 and 3, the operating body 8 has a operated portion 8A that is internally fitted into the operating hole 6a so as to be relatively rotatable (relatively rotating), and a screw that is screwed into the nut portion 7n of the plunger 7. It is configured as a rotating body-shaped component having a shaft portion 8B and a main body portion 8C having a flange portion 8f abutting on the inner side wall 6d on the base end side of the housing 6. A linear groove (an example of the operated portion) 16 that penetrates the cylindrical operated portion 8A in the radial direction and opens to the proximal end side is formed at the base end portion of the operated portion 8A. Further, the flange portion 8f is formed with a notch 8k that engages with the base end hook portion 10a of the torsion coil spring 10.

As shown in FIGS. 2 and 3, the torsion coil spring 10 is a winding spring that urges the housing 6 to rotate (twist) the operating body 8 in a predetermined direction around the axis P. The tip hook portion 10b of the torsion coil spring 10 is inserted into the insertion hole 6e formed in the end wall (housing lid 6B) of the housing 6, and the base end hook portion 10a is inserted into the notch 8k of the operating body 8 as described above. It is plugged in.

That is, the torsion coil spring 10 is an elastic mechanism that rotationally urges the operating body 8 in the direction in which the plunger 7 tends to protrude from the housing 6. Further, the cushioning spring 9 made of a coil spring is provided between the outer fitting portion 7A of the plunger 7 and the main body portion 8C of the operating body 8 in a state of surrounding the screw shaft portion 8B. The cushioning spring 9 can be expected to have an effect of suppressing rattling between the plunger 7 and the operating body 8 and an effect of preventing resonance. That is, the sliding surface between the operating body 8 and the plunger 7 (screwed portion between the screw shaft portion 8B and the nut portion 7n) and the sliding surface between the operating body 8 and the housing 6 (flange portion 8f and the inside on the base end side). The function of giving friction to the joint surface with the wall 6d) and attenuating the tensioner behavior (chain behavior) is exhibited.

As shown in FIGS. 2 and 3, in this chain tensioner T, the outer fitting portion 7A and the screw shaft portion 8B are screwed together. Therefore, when the operating body 8 is turned to the right, the operating body 8 and the plunger are turned. The screwing length with 7 increases, and the plunger 7 retracts and moves with respect to the housing 6 (in the direction of arrow X). When the operating body 8 is turned counterclockwise, the screwing length between the operating body 8 and the plunger 7 is reduced, and the plunger 7 projects and moves with respect to the housing 6 (in the direction of arrow Y).

The operating body 8 can be rotated and operated by a flat-blade screwdriver (not shown) inserted into the straight groove 16 from the operating hole 6a. As shown in FIG. 4, in the assembled state of the chain tensioner T to the engine E, the operation hole 6a of the housing 6 is closed by the sealing bolt 17. The sealing bolt 17 functions as a lid member that closes the operation hole 6a. [A stopper (not shown) is inserted into the operation hole 6a when assembling to the engine E, and the sealing bolt is inserted through a washer after assembly. 17 is screwed in].

The torsion coil spring 10 is housed in the internal space 6S in a state of being previously twisted so as to elastically urge the operating body 8 in the counterclockwise direction, and in a state where the torsion coil spring 10 is twisted. A force for turning the operating body 8 to the left, that is, a force for moving the plunger 7 in the protruding direction is acting. In other words, when the plunger 7 does not have a force in the retracting direction (arrow X direction) (a force pushed by the timing chain 4 in the used state), the plunger 7 is arbitrarily projected and moved by the torsion coil spring 10.

When the chain tensioner T shown in FIG. 4 is used (when assembled), the plunger 7 presses the timing chain 4 (tensioned portion 4a) inside the loop via the chain slider 5, and the timing chain 4 is used. Can be tensioned so that there is no slack. Since the operating body 8 is rotationally urged in the counterclockwise direction by the torsion coil spring 10 and a force that always tries to push out the plunger 7 more is always acting, the chain tensioner T constantly exerts an elastic tension force on the timing chain 4. It has the function of an auto tensioner to give to.

The sealing bolt 17 (see FIG. 4) is removed, and a turning tool having a ridge 19a (see FIG. 1) at the tip of a flat-blade screwdriver or the like is inserted into the operation hole 6a of the housing 6 and engaged with the straight groove 16. The plunger 7 can be moved in a protruding manner by turning the turning tool to the left, and the plunger 7 can be moved in and out by turning it to the right. Therefore, it is possible to put the chain tensioner T in the tension release state by using a turning tool such as a flat-blade screwdriver, and it is also possible to replace the timing chain 4 in the tension release state.

Next, the tensioner release tool A will be described. As shown in FIGS. 1 and 3, the tensioner release tool A has a support cylinder 18, a rotating shaft 19, and a turning portion 20, and timing by the chain tensioner T shown in FIGS. 2 and 3. It is configured as a special tool for releasing the tension of the chain 4. A regulation plate 21 that prevents the rotation shaft 19 from moving relative to the axis Z direction is bolted to the support cylinder 18, and a lock nut 22 for fixing the tensioner release tool A to the housing 6 is screwed. Has been done.

The structure of the tensioner release tool A will be described in detail. As shown in FIGS. 1 and 3, a support cylinder 18 having an external screw portion 18a that can be screwed into an operation hole 6a formed in the housing 6 of the chain tensioner T and a support cylinder 18 that is rotatably fitted into the support cylinder 18 are internally fitted. It has a rotating shaft 19 to be rotated, and a knob (an example of a rotating portion) 20 attached to the base end side of the rotating shaft 19 for rotating and operating the rotating shaft 19. The knob 20 includes a knob portion 20A that is rotated by a finger and a bolt portion 20B that is screwed into the base end nut portion 19c of the rotating shaft 19.

As shown in FIGS. 1 and 3, the operating body is rotatably housed in the housing 6 at the protruding end of the rotating shaft 19 from the support cylinder 18, and the operated portion 8A faces the operating hole 6a. An operating portion 19A that can be engaged with the operated portion 8A of 8 so as not to be relatively rotatable is formed, and the rotating portion 20 is rotated in a mounted state (see FIG. 3) in which the support cylinder 18 is screwed into the operating hole 6a. By the operation, the operating body 8 can be rotated via the rotating shaft 19 in which the operating portion 19A is engaged with the operated portion 8A. In addition, in FIGS. 1 and 3, the bolt for attaching the regulation plate 21 to the support cylinder 18 is omitted.

As shown in FIGS. 1 and 3, the support cylinder 18 includes a cylinder shaft portion 18B in which an inner hole 18b through which the rotating shaft 19 is passed and the above-mentioned external screw portion 18a are formed, and a large-diameter support main body portion 18A. It is configured as a component having a shape that becomes a rotating body with respect to the axis Z. In the support main body portion 18A, a large-diameter rotation hole 18c following the inner hole 18b is formed, and a screw hole 18d in a direction orthogonal to the axis Z is formed. A female screw portion 18e for bolting the regulation plate 21 is formed on the support main body portion 18A in a state of extending in a direction along the direction of the axis Z.

Although not shown, the screw hole 18d is screwed with a locking bolt (such as a wing bolt) that acts on the shaft body 19C (described later) to prevent the rotating shaft 19 from rotating with respect to the support cylinder 18. Has been done. That is, the screw hole 18d and the locking bolt (not shown) in the support cylinder 18 constitute a rotation prevention mechanism s that makes it impossible for the rotation shaft 19 and the support cylinder 18 to rotate relative to each other. The cylinder shaft portion 18B is provided with a lock nut 22 in a state of being screwed into the external thread portion 18a.

As shown in FIGS. 1 and 3, the rotation shaft 19 includes a shaft portion 19B that is internally rotatably fitted in the inner hole 18b and a shaft that is internally rotatably fitted in the rotation hole 18c. It is a component having a main body portion 19C. On the tip end side (chain tensioner T side) of the shaft portion 19B, an operation portion 19A that is tapered like a turning portion of a flat-blade screwdriver to have a flat shape is formed.

The end (tip) of the operating portion 19A is formed in a ridge 19a that can be fitted into a straight groove 16 formed on the base end surface of the operating body 8. An annular groove 23 into which the regulation plate 21 is fitted is formed in the shaft body portion 19C, and a large-diameter shaft end portion 19d having a proximal end nut portion 19c as a center is formed on the proximal end side (knob 20 side). Has been done.

As shown in FIGS. 1 and 3, the tensioner release tool A rotates to the support cylinder 18 in a state where the rotation shaft 19 is positioned at the axis Z by the regulation plate 21 as shown in FIGS. 1 and 3. It is internally fitted so that the rotating shaft 19 and the operating portion 19A can be freely rotated by the knob 20 on the base end side.
The tensioner release tool A is a maintenance tool for releasing the tensioning action of the timing chain 4 by the chain tensioner T, and its usage will be described below.

First, the sealing bolt 17 (see FIG. 4) attached to the chain tensioner T is removed from the housing 6. Then, as shown in FIG. 3, the support cylinder 18 is screwed into the operation hole 6a of the housing 6, the knob 20 is slowly turned while tightening slowly, and the operation portion 19A is inserted into the straight groove 16 of the operation body 8 to fit. Then, after turning the support cylinder 18 a little, the lock nut 22 is turned to attach the support cylinder 18 to the housing 6 in a fixed state.

Then, the knob 20 is operated by hand to rotate the rotating shaft 19, the operating body 8 is rotated to the right against the elastic urging force of the torsion coil spring 10, and the plunger 7 is retracted and moved (in the direction of arrow X). Move). Then, when the plunger 7 is further retracted and moved to release the tension of the timing chain 4, the wing bolt (not shown) screwed into the screw hole 18d is tightened to lock the rotation shaft 19. It is a work procedure.

By the tensioner release tool A, the tension of the chain tensioner T is released, the timing chain 4 is in a loosened state, and maintenance work such as replacement work by removing the timing chain 4 from the three gears 1G, 2G, and 3G can be performed. That is, by using the dedicated tensioner release tool A, it is possible to easily and conveniently retract the plunger 7 to retract it and maintain the retracted state, so that preparations for starting maintenance work such as timing chain 4 can be performed. There is an advantage that the work (work to cancel the function of the chain tensioner T) can be made more efficient.

To restore the function of the chain tensioner T, the series of work procedures described above may be reversed. That is, after loosening the wing bolt (not shown) of the screw hole 18d, turn the knob 20 counterclockwise to project the plunger 7 to its original position, then loosen the locknut 22 and turn the support cylinder 18 in the loosening direction. It is removed from the housing 6 and finally the sealing bolt 17 is screwed into the operation hole 6a.

As described above, according to the chain tensioner T according to the present invention, the operating body 8 can be turned from the operating hole 6a by using a tool or the like, and the plunger 7 can be artificially moved to move forward or backward. .. Therefore, there is a convenience that various maintenance work such as loosening the timing chain 4 by forcibly moving the plunger 7 in and out to release the tension and replacing the timing chain without removing the chain tensioner T can be performed.

And since the plunger 7 is elastically urged in the direction of protruding and moving from the housing 6 by the torsion coil spring 10 built in the housing, the function of the auto tensioner that does not need to artificially adjust the tension force on a regular basis is exhibited. There is also the advantage of being. Further, since it is not necessary to remove the chain tensioner T during maintenance work such as the timing chain 4, a new gasket is not required and workability can be improved.

Then, if the tensioner release tool A is used, the effect of moving the plunger 7 in and out without removing the chain tensioner T to release the tension can be obtained easily, conveniently, and quickly. Moreover, the plunger 7 can be projected and retracted with a simple operation that can be done by simply turning the knob 20, and there is also the convenience that the plunger 7 can be locked and fixed at an arbitrary position by a wing bolt or the like.

Therefore, if the tensioner release tool A is used, maintenance work such as adjusting the tension of the timing chain 4 and releasing the tension can be performed without removing the chain tensioner T from the engine, and as described above, the preparatory work for starting the maintenance work can be performed. The effect is simple, convenient, and quick.

[Another Embodiment]
The operated portion 16 of the operating body 8 may be a cross-shaped groove that can be turned with a Phillips screwdriver, or may have another structure. A wing nut may be screwed onto the support cylinder 18 instead of the lock nut 22, so that no tool such as a spanner is required and the tensioner release tool A can be handled more conveniently.

4 Timing chain 6 Housing 6a Operation hole 7 Plunger 8 Operation body 10 Elastic mechanism (torsion coil spring)
16 Operated part (straight groove)
17 Closure member (sealing bolt)
18 Support cylinder 19 Rotating shaft 19A Operating part 19a Splash 20 Turning part 22 Locknut A Tensioner release tool P Axis center T Chain tensioner

Claims (9)

A plunger that can be pressed in the direction of tensioning the timing chain,
A housing that supports the plunger so that it cannot rotate relative to each other and can move in and out.
An operating body that has an axial center along the moving direction of the plunger and is rotatably housed in the housing while being screwed into the plunger.
An operation hole formed in the housing for rotating the operating body from the outside of the housing,
A chain tensioner installed in the engine. The chain tensioner according to claim 1, wherein an elastic mechanism for rotating and urging the operating body in a direction in which the plunger tends to protrude from the housing is provided. 2. The elastic mechanism is configured by accommodating a coil spring whose one end is locked to the housing and the other end of which is locked to the operating body in the housing while surrounding the operating body. The chain tensioner described in. The chain tensioner according to any one of claims 1 to 3, wherein a lid member that closes the operation hole is detachably mounted on the housing. A support cylinder that can be screwed into an operation hole formed in the housing of the chain tensioner, a rotation shaft that is rotatably fitted in the support cylinder, and a rotating portion for rotating and operating the rotation shaft. Have and
At the tip of the rotating shaft, an operating portion that is rotatably housed in the housing and is rotatably engaged with the operated portion of the operating body having the operated portion facing the operation hole is provided. Formed,
By turning the turning portion in the mounted state in which the support cylinder is screwed into the operating hole, the operating body is turned via the rotating shaft in which the operating portion is engaged with the operated portion. A tensioner release tool that is configured to be operable. The tensioner release tool according to claim 5, wherein a lock nut for locking the support cylinder screwed into the operation hole to the housing is screwed to the support cylinder. The tensioner release tool according to claim 5 or 6, wherein the support cylinder is provided with a rotation blocking mechanism that makes it impossible for the rotation shaft and the support cylinder to rotate relative to each other. The operation portion of the rotation shaft according to any one of claims 5 to 7, wherein the operation portion of the rotation shaft has a ridge that can be fitted into a linear groove formed on an end surface of the operation body as the operation portion. Tensioner release tool. 6. The tensioner release tool described.

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