JP4100628B2 - Spring tensioner for engine - Google Patents

Description

  The present invention relates to a spring tensioner for an engine that applies an appropriate tension to a timing belt or a timing chain of a vehicle engine.

  Conventionally, a transmission medium such as a timing chain that transmits rotation between a crankshaft and a camshaft of a vehicle engine has various kinds of vibrations to suppress vibrations generated during traveling and to maintain appropriate tension. Tensioners are used, and in particular, in the case of a vehicle engine or a small engine with a constant load torque, the variation range of the engine speed is small. Widely used (see Patent Document 1).

For example, as shown in FIG. 8, in the conventional spring tensioner 800, a plunger 820 is slidably inserted into a plunger receiving hole 811 formed in the housing 810, and one end of the plunger 820 is opened. A hollow portion 821 is formed and a plunger energizing spring 830 that energizes the plunger 820 in the protruding direction is accommodated across the plunger accommodating hole 811 and the hollow portion 821, and vibrations generated when the vehicle engine timing chain travels are accommodated. It suppresses and maintains proper tension.
JP 54-23870 (first page, FIG. 2)

  However, the plunger urging spring 830 of the conventional hydraulic tensioner 800 as shown in FIG. 8 is accommodated between the plunger accommodating hole 811 and the hollow portion 821 by using the elastic force of the plunger urging spring 830. 9, the plunger biasing spring 830 has a seating deviation X as shown in FIG. 9 with respect to the bottom of the plunger receiving hole 810 due to an excessive impact received through the plunger 820 when the timing chain travels. In the case where such a displacement X of the plunger biasing spring 830 occurs, when the plunger 820 moves backward, the bottom of the plunger receiving hole 811 of the housing 810 and the rear end of the plunger 820 In between, the plunger biasing spring 830 is buckled and easily caught between the rear end portion of the plunger 820 and the like.

As a result, as shown in FIG. 9, the plunger biasing spring 830 buckled in the plunger receiving hole 811 of the housing 810 becomes an obstacle when the plunger 820 is retracted, and the plunger 820 cannot sufficiently retract. The load of the plunger biasing spring 830 is extremely increased, and there is a problem that an appropriate tension cannot be applied to the timing chain.
In addition, there is a problem that the plunger 820 abnormally contacts the plunger biasing spring 830 buckled in the plunger receiving hole 811 to cause excessive wear and seriously deteriorate the durability.

  Therefore, the problem to be solved by the present invention, that is, the object of the present invention is to solve the problems of the prior art as described above, and the close contact winding of the plunger biasing spring in the plunger receiving hole of the housing. To provide a spring tensioner for an engine that can be securely assembled without causing the seat part to expand and contract without being displaced, and to prevent excessive increase in spring load, wear, and damage due to abnormal contact between the plunger biasing spring and the plunger. It is.

  In order to achieve the above object, the invention according to claim 1 includes a plunger projecting slidably from a plunger receiving hole of a housing toward a traveling chain and a hollow portion of the plunger communicating open to the plunger receiving hole. And a plunger biasing spring that is housed between the plunger housing hole and biases in the direction in which the plunger protrudes, wherein the plunger biasing spring is expanded and contracted by the plunger. A tightly wound part and a compression movable part connected to the tightly wound part to press and urge the plunger, and the tightly wound part of the spring for biasing the plunger further urges the bottom of the plunger receiving hole. The cylindrical seat is fixed in close contact with the inner peripheral wall of the spring seating positioning portion. It is intended to solve.

The spring tensioner for an engine according to the present invention includes a plunger projecting slidably from a plunger housing hole of a housing toward a travel chain, a hollow portion of the plunger communicating openly toward the plunger housing hole, and a plunger housing hole. Is provided with a plunger biasing spring that is biased in the direction in which the plunger protrudes, so that not only an appropriate tension can be applied to the timing belt, timing chain, etc. of the vehicle engine. By providing the following configuration, a specific effect can be obtained.
In other words, the spring tensioner for an engine according to the present invention has a close fitting portion of the plunger biasing spring closely fitted to the inner peripheral wall of the spring seating positioning portion formed of a cylindrical recess hole in which the bottom portion of the plunger receiving hole is further countersunk. By being fixed in the combined state, the tightly wound portion of the spring for biasing the plunger can be securely assembled without being expanded or contracted in a sliding contact state with respect to the spring seating positioning portion formed of a cylindrical hollow hole. The plunger biasing spring does not slip in the plunger receiving hole of the housing even if it receives an excessive impact via the plunger during the timing chain running, and the plunger is not located between the rear end of the plunger and the bottom of the plunger receiving hole. Extremely increased spring load, wear or damage due to abnormal contact between the plunger rear end and the plunger biasing spring It can be reliably prevented.

  Further, a timing chain is constituted by a close-contact winding portion that is fixed by fitting a plunger biasing spring to the spring seating positioning portion and a compression movable portion that is connected to the close-contact winding portion and presses and biases the plunger. Even if the tension fluctuates, the tightly wound portion fitted to the spring seating positioning portion is securely assembled to the spring seating positioning portion formed of a cylindrical recess hole without sliding and moving in a sliding contact state. In addition, it is possible to completely prevent wear and breakage that tend to occur in the plunger urging spring, and it is possible to positively urge the plunger without being constrained by the spring seating positioning portion.

  A spring tensioner for an engine according to the present invention includes a tightly wound portion in which a plunger biasing spring is not expanded and contracted by the plunger, and a compression movable portion that is connected to the tightly wound portion and presses and biases the plunger. The tightly wound portion of the urging spring is fixed in a close fitting state to the inner peripheral wall of the spring seating positioning portion formed of a cylindrical recess hole in which the bottom portion of the plunger receiving hole is further countersunk, whereby the plunger of the housing The tightly wound portion of the plunger urging spring in the receiving hole is securely assembled without expanding or contracting to prevent excessive spring load, wear or damage due to abnormal contact between the plunger urging spring and the plunger. As long as it is to be prevented, the concrete tensioner form may be any, for example, in the plunger receiving hole of the housing. In a direction in which the plunger is protruded by being housed in a high-pressure chamber comprising a plunger that has a hollow portion that communicates with the plunger and that slidably protrudes from the plunger accommodation hole toward the traveling chain, and the plunger accommodation hole and the hollow portion. A hydraulic tensioner having a plunger urging spring for urging the pressure oil in the high pressure chamber, and a rack and a housing in which a plunger is formed on the hydraulic tensioner and the spring tensioner. There is no problem even if a ratchet mechanism is added.

  Further, the specific installation form of the spring seating positioning portion may be a hollow hole that is further countersunk at the bottom of the plunger receiving hole, and such a hollow hole effectively increases the expansion / contraction stroke of the spring for biasing the plunger. Can be secured well.

An engine spring tensioner according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a view showing how the engine spring tensioner is used, and FIG. 2 is a cross-sectional view of the engine spring tensioner as a first reference example for helping understanding of the engine spring tensioner of the present invention. FIG. 3 is a sectional view of a spring tensioner for an engine which is a second reference example for helping understanding of the spring tensioner for an engine of the present invention, and FIG. 4 is an engine which is an embodiment of the present invention. FIG. 5 is a sectional view of the plunger biasing spring shown in FIG. 4, and FIG. 6 is a third reference for helping understanding of the spring tensioner for an engine of the present invention. FIG. 7 is a cross-sectional view of a spring tensioner for an engine as an example, and FIG. 7 is a cross-sectional view of a spring tensioner for an engine that is a fourth reference example for helping understanding of the spring tensioner for an engine of the present invention.

  First, as shown in FIGS. 1 and 2, a spring tensioner 100, which is a first reference example for helping understanding of the present invention, is fixed to a drive side sprocket S1 rotated by a crankshaft of an engine and a camshaft. Is attached to the engine body on the slack side of the timing chain C spanned between the driven sprockets S2 and S2, and the plunger 120 protrudes from the front surface of the housing 110 so that the plunger 120 protrudes and retracts. Tension is applied to the slack side of the timing chain C via the movable lever L1 by pressing the back surface in the vicinity of the swing end of the movable lever L1 that is swingably supported on the engine body side. A fixed guide L2 for guiding the travel of the timing chain C is attached to the tension body side of the timing chain C on the engine body side.

  The driving side sprocket S1 and the driven side sprocket S2 are driven by the timing chain C traveling when the driving side sprocket S1 rotates in the direction indicated by the arrow. The side sprocket S2 rotates in the direction of the arrow, and the rotation of the driving side sprocket S1 is transmitted to the driven side sprocket S2.

  In the spring tensioner 100 of the first reference example shown in FIG. 2, a plunger 120 having an outer appearance is slidably inserted into a plunger receiving hole 111 formed in the housing 110, and one end of the plunger 120 is opened. A hollow portion 121 is formed, and a plunger biasing spring 130 made of a coil spring that biases the plunger 120 in the protruding direction is accommodated across the plunger receiving hole 111 and the hollow portion 121, and further, the plunger biasing force The spring 130 constantly urges the plunger 120 so that the tip of the plunger 120 protrudes outside the plunger receiving hole 111.

Therefore, the spring seating positioning portion 112 characterized by the spring tensioner 100 of the first reference example is formed of a cylindrical recess hole in which the bottom of the plunger receiving hole 111 is further countersunk, and the spring seating positioning portion including the recess hole. The plunger biasing spring 130 is securely assembled and fixed to 112.
Therefore, in the spring tensioner 100 of the first reference example for helping understanding of the present invention, even if the plunger 120 is retracted due to excessive impact through the plunger 120 during traveling of the timing chain, the plunger receiving hole 111 in the housing 110 is not affected. Therefore, the plunger biasing spring 130 is not displaced or buckled, and the plunger biasing spring 130 is bent between the bottom of the plunger receiving hole 111 of the housing 110 and the rear end of the plunger 120 in a bent state. In addition, wear and breakage due to abnormal contact between the rear end portion of the plunger 820 and the plunger biasing spring 830 as in the prior art is reliably prevented, and an appropriate tension is applied to the timing chain C.

  3 is a modification of the spring tensioner 100 of the first reference example shown in FIG. 2, and is a spring seat positioning portion 212. The spring tensioner 200 shown in FIG. Are chamfered or tapered to facilitate attachment of the plunger biasing spring 230 made of a coil spring to the inlet 212a of the hollow hole, and the rest of the configuration is the same as that of the first reference example described above. There is no difference from the spring tensioner 100.

4 to 5, the engine spring type tensioner 300 according to the embodiment of the present invention has a cylindrical depression in which a plunger biasing spring 330 made of a coil spring is further countersunk at the bottom of the plunger receiving hole 311. It is composed of a tightly wound portion 331 that is fitted and fixed to a spring seating positioning portion 312 made of a hole, and a compression movable portion 332 that is connected to the tightly wound portion 331 and presses and biases the plunger 320. The remaining configuration is not different from the spring tensioner 100 described above.
Therefore, the engine spring tensioner 300 according to the embodiment of the present invention has the timing chain C in tension in addition to the effect exhibited by the engine tensioner 100 of the first reference example for helping understanding of the present invention as described above. Even if it fluctuates, the tightly wound portion 331 fixed in a close fitting state to the inner peripheral wall of the spring seating positioning portion 312 formed of a cylindrical hollow hole expands and contracts in a sliding contact state with respect to the spring seating positioning portion 312. Therefore, the plunger biasing spring 330 can be completely prevented from being worn or damaged, and the compression movable portion 332 is not restrained by the spring seating positioning portion 312. The effect is enormous, for example, 320 can be reliably pressed and urged.

Next, a spring tensioner 400 that is a third reference example for helping understanding of the present invention shown in FIG. 6 is a modification of the spring tensioner 100 that is the first reference example of the present invention shown in FIG. The spring seating positioning portion 412 of the spring tensioner 400 of the third reference example is constituted by a cylindrical protrusion protruding from the bottom of the plunger receiving hole 411 toward the plunger 420, and the spring formed by this cylindrical protrusion. The plunger biasing spring 430 is securely assembled and fixed to the seating positioning portion 412.
Therefore, the spring tensioner 400 according to the third reference example of the present invention has a plunger urging force in the plunger receiving hole 411 of the housing 410 even when the plunger 420 is retracted due to excessive impact through the plunger 420 during traveling of the timing chain. The spring 430 does not slip or buckle, and the plunger biasing spring 430 is not sandwiched in a bent state between the bottom of the plunger receiving hole 411 of the housing 410 and the rear end of the plunger 420. Thus, wear and breakage due to abnormal contact between the rear end portion of the plunger 820 and the plunger biasing spring 830 are surely prevented, and an appropriate tension is applied to the timing chain C.

A spring tensioner 500, which is a fourth reference example for helping understanding of the present invention shown in FIG. 7, is a modification of the spring tensioner 400 which is the third reference example of the present invention shown in FIG. A plunger urging spring 530 is composed of a tightly wound part 531 fitted and fixed to the spring seating positioning part 512, and a compression movable part 532 connected to the tightly wound part 531 to press and urge the plunger 520. The remaining configuration is the same as that of the spring-type tensioner 400 described above.
Therefore, the spring tensioner 500, which is a fourth reference example for helping understanding of the present invention, has a spring even when the tension of the timing chain C fluctuates in addition to the effect exerted by the tensioner 400 of the third reference example as described above. Since the tightly wound portion 531 that is closely fitted to the outer peripheral wall of the seating positioning portion 512 is securely assembled to the spring seating positioning portion 512 without extending or contracting in a sliding state, it is used for biasing the plunger. The wear and breakage that tend to occur in the spring 530 are completely prevented, and the compression movable portion 532 is surely pressed and biased without being restrained by the spring seating positioning portion 512.

The use aspect figure using the spring type tensioner for engines. Sectional drawing of the spring type tensioner which is the 1st reference example for helping an understanding of this invention. Sectional drawing of the spring type tensioner which is the 2nd reference example for helping an understanding of this invention. Sectional drawing of the spring type tensioner for engines which is an Example of this invention. Sectional drawing of the spring for biasing a plunger shown in FIG. Sectional drawing of the spring type tensioner which is the 3rd reference example for helping an understanding of this invention. Sectional drawing of the spring type tensioner which is the 3rd reference example for helping an understanding of this invention. Sectional drawing of the conventional spring type tensioner. The figure which the buckling spring of the spring tensioner shown in FIG. 8 buckled.

Explanation of symbols

100, 200, 300, 400, 500, 800 ... spring tensioners 110, 210, 310, 410, 510, 810 ... housings 111, 211, 311, 411, 511, 811 ... plunger receiving holes 112 , 212, 312, 412, 512 ・ ・ ・ Seating positioning part 120, 220, 320, 420, 520, 820 ・ ・ ・ Plunger 121, 221, 321, 421, 521, 821 ・ ・ ・ Hollow part 130, 230, 330 , 430, 530, 830... Plunger biasing spring 331, 531... Closely wound portion 331, 531..., Compression movable portion S1... Driving side sprocket S2.・ Timing chain L1 ... Moveable lever L2 ... Fixed guide X ... Seating deviation

Claims (1)

A direction in which the plunger protrudes slidably from the plunger accommodation hole of the housing toward the traveling chain, and is accommodated between the plunger hollow and the plunger accommodation hole that communicates and opens toward the plunger accommodation hole. In a spring tensioner for an engine having a plunger biasing spring that biases
The plunger biasing spring includes a tightly wound portion that does not expand and contract by the plunger, and a compression movable portion that is connected to the tightly wound portion and presses and biases the plunger.
The tightly wound portion of the plunger biasing spring is fixed in a close fitting state with the inner peripheral wall of the spring seating positioning portion formed of a cylindrical recess hole in which the bottom portion of the plunger receiving hole is further countersunk. Features a spring tensioner for engines.

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