JP4393784B2 - Hydraulic auto tensioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic auto tensioner mainly for adjusting the tension of a belt for driving an automobile auxiliary machine.
[0002]
[Prior art]
A tension pulley is rotatably provided at the swing side end of an arm that is swingably mounted on the engine block, and the tension pulley is pressed against the belt by applying an adjustment force of a hydraulic auto tensioner to the arm. 2. Description of the Related Art Conventionally, a belt tension adjusting device that absorbs a change in tension with a hydraulic auto tensioner to keep the belt tension constant is known.
[0003]
As a hydraulic auto tensioner used in the belt tension adjusting device, the rear end of the push rod is inserted into a cylinder filled with hydraulic oil, and the elastic force of the tension adjusting spring is applied to the push rod to A hydraulic damper mechanism that provides outward projecting properties and cushions the pushing force applied to the push rod is incorporated in the cylinder so that the tension adjustment spring and the hydraulic damper mechanism absorb changes in belt tension. There is something that was made.
[0004]
In the belt tension adjustment device that employs the above hydraulic auto tensioner, the cylinder and pusher are installed when the hydraulic auto tensioner that connects the cylinder of the hydraulic auto tensioner to the engine block and the tip of the push rod to the arm is assembled. The rod is pushed against the elastic force of the tension adjustment spring, and the hydraulic oil in the pressure chamber of the hydraulic damper mechanism leaks into the reservoir chamber through a minute gap, causing the cylinder and push rod to contract relative to each other. It is necessary to connect the cylinder to the engine block and connect the tip of the push rod to the arm, and then wind the belt after the connection. For this reason, there is a problem that it takes much time to assemble the hydraulic auto tensioner and wind the belt.
[0005]
In order to solve such a problem, Patent Document 1 proposes a hydraulic auto tensioner in which a cylinder and a push rod are held in a contracted state by attaching a cover.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-306859
[Problems to be solved by the invention]
By the way, in the hydraulic auto tensioner described in Patent Document 1, since it is necessary to hold the tension adjustment spring having a large spring load in a state of being compressed by the cover, it is necessary to increase the strength of the cover by making the cover thick. There is a disadvantage that the cost is high.
[0008]
In addition, the cover is configured to hold the hydraulic auto tensioner in a contracted state by engaging with a spring seat provided on the cylinder and a spring seat provided on the push rod, so that the connecting hole of the protrusion provided on each spring seat In many cases, there is a shift in parallelism between the two or the connection holes are relatively inclined. In this case, since it is necessary to assemble the hydraulic auto tensioner by adjusting the parallelism and inclination of the connecting hole, the workability of the assembly is lowered.
[0009]
An object of the present invention is to provide a hydraulic auto tensioner that is easy to assemble and inexpensive.
[0010]
[Means for Solving the Problems]
In order to solve the above problems, in the present invention, a cylinder filled with hydraulic oil and provided with a protruding portion having a connecting hole at a closed end, and a rear end portion inserted into the cylinder, the cylinder A push rod provided with a projecting portion having a connecting hole at the tip facing the outside, a tension adjusting spring that imparts outward pushability to the push rod, and the push rod incorporated into the cylinder and applied to the push rod in hydraulic auto-tensioner comprising a hydraulic damper mechanism that buffers the pushing force, and a polygonal surface having a rounded corner of the outer periphery of the projecting portion provided in the cylinder, the protruding portion provided on the push rod forming a cylindrical surface centered on the said connecting hole to the outer periphery, is pushed relatively the cylinder and the push rod so as to along its cylindrical surface and the polygonal surface shrinkage It had adopted a configuration in which passing over cleavable endless member having flexibility which holds the state.
[0011]
Here, as the endless member, a member made of a steel wire having both ends fixed by crimping of a clip or a member made of an endless belt having poor stretchability can be adopted.
[0012]
As described above, by holding the cylinder and the push rod in a contracted state in which the cylinder and the push rod are relatively pushed by the flexible endless member, it is possible to reduce the cost of the hydraulic auto tensioner compared to the case in which the cover is held in the contracted state. Reduction can be achieved.
[0013]
Further, by passing the endless member over the outer periphery of the protrusion provided on each of the cylinder and the push rod, there is almost no deviation in parallelism between the connecting holes formed in each protrusion, Since the connecting hole is not relatively inclined, a hydraulic auto tensioner that can be easily assembled can be obtained.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the arm 1 is supported so as to be swingable about a fulcrum shaft 2 attached to the engine block, and a tension pulley 3 is rotatably supported at the swing side end of the arm 1. Yes.
[0015]
The arm 1 is urged by a hydraulic auto tensioner 10 in a direction in which the tension pulley 3 presses the belt B shown in FIG.
[0016]
As shown in FIG. 2, the hydraulic auto tensioner 10 has a cylinder 11 whose lower portion is closed, and an oil seal 12 is attached to the upper opening of the cylinder 11 to fill the inside of the cylinder 11 with hydraulic oil and hydraulic oil. A hydraulic damper mechanism 14 is provided at the lower end of a push rod 13 that slidably penetrates the oil seal 12 to prevent leakage of air in an air reservoir provided on the surface to the outside. 11 is provided with a projecting property to the outside by a tension adjusting spring 15 provided outside.
[0017]
The hydraulic damper mechanism 14 slidably incorporates a plunger 16 connected to the lower end of the push rod 13 into a steel sleeve 17 fitted in the lower part of the cylinder 11, and is provided below the plunger 16. The pressure chamber 18 and the reservoir chamber 19 provided above are communicated with each other through a passage 20 formed in the plunger 16, and a check valve 21 is provided in the passage 20.
[0018]
The check valve 21 closes the passage 20 when the pressure in the pressure chamber 18 becomes higher than the pressure in the reservoir chamber 19, and prevents hydraulic oil in the pressure chamber 18 from flowing into the reservoir chamber 19 from the passage 20. Reference numeral 22 denotes a plunger spring that presses the plunger 16 against the lower end of the push rod 13.
[0019]
The tension adjustment spring 15 is supported at its lower end by a spring seat 23 provided on the outer periphery of the lower end of the cylinder 1, and the upper end presses a spring seat 24 provided at the upper end of the push rod 13 to protrude outward from the push rod 13. Has been given sex.
[0020]
The lower surface of the spring seat 23 provided in the cylinder 11 protruding portion 25 is provided, consolidated hole 26 which penetrates both sides thereof protruding portions 25 are formed. The projecting portion 25 is connected to the engine block A shown in FIG. 2 by tightening a bolt 27 inserted into the connecting hole 26.
[0021]
A protrusion 28 is provided on the upper surface of the spring seat 24 of the push rod 13, and a connecting hole 29 penetrating the both sides is formed in the protrusion 28. The protrusion 28 is connected to the arm 1 by tightening a bolt 30 inserted into the connection hole 29.
[0022]
In the hydraulic auto tensioner 10 configured as described above, a flexible endless member 31 is stretched over the outer periphery of the protruding portion 25 provided on the cylinder 11 and the outer periphery of the protruding portion 28 provided on the push rod 13. The cylinder 11 and the push rod 13 are held in a contracted state in which the cylinder 11 and the push rod 13 are relatively pushed by the endless member 31.
[0023]
In FIG. 1 and FIG. 2, the endless member 31 is supported by a steel wire 33 having both ends fixed by crimping of the clip 32, but the endless member 31 is not limited to this.
[0024]
For example, an endless belt 34 may be used as shown in FIGS. The endless belt 34 is made of a flexible material with poor shrinkage, such as rubber, plastic, cloth, steel, and the like.
[0025]
As described above, the endless member 31 is stretched between the outer periphery of the projecting portion 25 of the cylinder 11 and the outer periphery of the projecting portion 28 of the push rod 13 to keep the hydraulic auto tensioner 10 in a contracted state. The operation of connecting the protruding portion 25 of the cylinder 11 to A and connecting the protruding portion 28 of the push rod 13 to the arm 1 and assembling the hydraulic auto tensioner 10 to contract and hold the hydraulic auto tensioner 10 Can be made unnecessary. For this reason, the hydraulic auto tensioner 10 can be assembled very easily, and the belt B can be easily transferred.
[0026]
Further, by passing the endless member 31 over the outer periphery of the protrusions 25 and 28 provided in the cylinder 11 and the push rod 13, the connection holes 26 and 29 formed in the protrusions 25 and 28 are connected to each other. There is very little shift in parallelism, and there is no relative inclination. Therefore, it is possible to obtain the hydraulic auto tensioner 10 that can be easily assembled.
[0027]
After the assembly of the hydraulic auto tensioner 10, the endless member 31 is cut. As a result of the cutting, the push rod 13 is moved outward by the pressing of the tension adjusting spring 15, and the arm 1 is swung around the fulcrum shaft 2 to press the tension pulley 3 against the belt B as shown in FIG. .
[0028]
In the hydraulic auto tensioner 10, the tension change of the belt B is absorbed by the hydraulic damper mechanism 14 and the tension adjustment spring 15.
[0029]
【The invention's effect】
As described above, in the present invention, the hydraulic auto tensioner is held in a contracted state by a flexible endless member made of a steel wire or an endless belt, so that the hydraulic auto tensioner is contracted by attaching a cover. The cost of the hydraulic auto tensioner can be reduced as compared with that held in a state.
[0030]
In addition, since the endless member is passed over the outer periphery of the protruding portion provided in each of the cylinder and the push rod, a deviation occurs in parallelism between the connecting holes formed in each protruding portion, or the connecting holes It is possible to obtain a hydraulic auto tensioner that does not tilt relatively easily and can be easily assembled.
[Brief description of the drawings]
FIG. 1 is a front view of a belt tension adjusting device employing a hydraulic auto tensioner according to the present invention. FIG. 2 is a longitudinal side view showing the hydraulic auto tensioner of FIG. FIG. 4 (I) is a front view showing another embodiment of the hydraulic auto tensioner according to the present invention, and (II) is a side view of (I).
DESCRIPTION OF SYMBOLS 11 Cylinder 13 Push rod 14 Hydraulic damper mechanism 15 Tension adjustment spring 25 Projection part 26 Connection hole 28 Projection part 29 Connection hole 31 Endless member 32 Clip 33 Steel wire 34 Endless belt

Claims (3)

There is a cylinder filled with hydraulic oil and provided with a protruding portion having a connecting hole at the closed end, and a protruding portion having a connecting hole at the leading end facing the outside of the cylinder, the rear end portion being inserted into the cylinder. Hydraulic pressure comprising a provided push rod, a tension adjusting spring that imparts outward pushability to the push rod, and a hydraulic damper mechanism that is incorporated in the cylinder and cushions the pushing force applied to the push rod. in formula auto tensioner, and a polygonal surface having a rounded corner of the outer periphery of the projecting portion provided on the cylinder, forming a cylindrical surface centered on the said coupling hole outside circumference of the protruding portion provided on the push rod and, cleavable endless flexible to hold the contracted state of the cylinder and the push rod is pushed relatively to along its cylindrical surface and the polygonal surface Hydraulic auto-tensioner, characterized in that it passes over wood. The hydraulic auto tensioner according to claim 1, wherein the endless member is made of a steel wire having both ends fixed by crimping of a clip. The hydraulic auto tensioner according to claim 1, wherein the endless member is an endless belt having poor stretchability.

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