JPH0640358Y2 - Belt auto tensioner - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention adjusts the tension of an automatic tensioner for a power transmission belt used in an engine, particularly a toothed timing belt for transmitting power of an engine crankshaft of an automobile. Concerning the belt auto tensioner.

[Conventional technology]

For example, in an automobile engine, there is known an automatic tensioner device that prevents loosening of a toothed timing belt that is stretched between a crankshaft pulley and a camshaft pulley and adjusts tension.

As shown in FIG. 13, the above-mentioned auto tensioner device includes an idler pulley 51 that engages with a belt 50 that transmits engine power.
And an arm that swingably supports this idler pulley 51.
52 and a tensioner 53 that presses the arm 52 against the tight side of the belt 50.

As shown in FIGS. 14 and 15, the tensioner 53 incorporates a piston rod 55 into the cylinder 54 so as to be movable in the axial direction, and supports the variable load from the belt 50 inside the cylinder 54 to support the idler pulley 51. And a damper mechanism 56 that prevents vibration of the belt 50 and a spring 57 that adjusts the tension of the belt 50.
It has a structure with.

By the way, in the tensioner 53 as described above, the piston rod 55 normally projects due to the pressing force of the spring 57, and the piston rod 55 has to be pushed into an appropriate position when mounted on the engine. Since pushing requires a lot of labor and time, it is necessary to employ a means for keeping the piston rod 55 in the pushed state in advance.

As shown in FIGS. 14 and 15, the conventional means described above uses a stopper pin between the end of the cylinder 54 on the opening side and the piston rod 55.
Push the piston rod 55 through 58 and fix it in the position,
The structure was such that the stopper pin 58 was pulled out when setting it on the engine.

[Problems to be solved by the device]

By the way, the structure using the stopper pin as described above is
There are problems listed below.

(I) When setting the stopper pin 58, the hole alignment in the axial direction and the rotation direction between the cylinder 54 and the rod 55 is troublesome.

(II) It is necessary to machine a pin hole in the radial direction of the cylinder 54 and the rod 55 and to align the holes, which results in a high cost.

(III) Since the pin hole arrangement at the end of the cylinder 54 and the pin hole of the rod 55 are arranged so as not to interfere with the seal member, the cylinder 54 and the rod 55 are lengthened and the autotensioner is enlarged.

(IV) Since the stopper pin 58 is discarded after it is mounted on the engine, it takes time and effort to find an appropriate pin during reassembly.

The present invention has been made to solve the above problems, and it is possible to perform at low cost with a structure that can easily hold the pushed state of the piston rod in the tensioner, and to shorten the length of the cylinder and the tip of the piston rod. The purpose is to provide an automatic belt tensioner that can be re-set conveniently.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, the present invention provides a pair of opposed plates, which form a circumferential groove on the outer peripheral surface of the opening end of the cylinder, and are fitted to both ends of the substrate at the opening end of the cylinder. A stopper formed by providing a bent piece elastically fitted to the peripheral groove at the tip edge, and selectively engaged with the bent piece of the stopper by external fitting while being elastically expanded and guided to the peripheral groove. A pair of positioning recesses are provided side by side, and the base plate has a notch that allows the piston rod to come out at a position corresponding to the tip of the piston rod when the one recess is engaged with the circumferential groove. On the other hand, a stopper portion is provided at a position corresponding to the tip of the piston rod when the recessed portion is engaged with the circumferential groove to prevent the piston rod from coming off.

[Action]

When one stopper is engaged with the circumferential groove while the stopper is elastically fitted and attached to the circumferential groove of the cylinder, the notched portion faces the piston rod and the piston rod projects. .

When the stopper is pushed in and the stopper is moved while being guided by the circumferential groove, and the other recessed part is fitted in the circumferential groove, the stopper part of the substrate faces the tip of the piston rod and the tip of the rod is stopped. It is prevented from coming out by supporting it with a part.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 12 of the accompanying drawings.

1 to 5 show a first example of the present invention,
In the auto tensioner, a peripheral groove 3 is provided on the outer peripheral surface of the opening end of the cylinder 2, a stopper 11 is attached to the opening end of the cylinder 2 using the peripheral groove 3, and a circumferential groove 5 is attached to the tip of the piston rod 4. Is provided.

The auto tensioner 1 has shown an example in which the spring 6 for pushing the piston rod 4 into the cylinder 2 to adjust the tension of the belt and the stroke adjusting shaft 8 screwed into the screw hole 7 of the piston rod 4 are incorporated. However, the structure is not limited to this, and any linear motion type may be used.

The stopper 11 is provided with a pair of opposed plates 13 and 13 which are fitted on the open ends of the cylinder 2 at both ends of the rectangular substrate 12, and elastically fitted to the circumferential groove 3 at the tip edges of the opposed plates 13 and 13. Bending piece 1
4 and 14 are provided.

Two sets of arc-shaped positioning recesses 15, 16 matching the bottom surface diameter of the circumferential groove 3 are provided side by side at the tip edges of both bending pieces 14, 14, and both positioning recesses 15, 16 are provided. Can be selectively engaged with the peripheral groove 3 while being elastically expanded and guided.

The base plate 12 is allowed to come out of the piston rod 4 at a position corresponding to the tip of the piston rod 4 in the state shown in FIG. 4 is engaged with the circumferential groove 3 of the piston rod 4 at a position corresponding to the tip of the piston rod 4 in the state shown in FIG. Then, a stopper portion 18 for preventing the piston rod 4 from coming out is provided.

The notch 17 is formed by a notch that is wider than the outer diameter of the piston rod 4 and opens at one side edge of the substrate 12.

The stopper portion 18 is formed as a notch having a width that is continuous with the inner end of the cutout portion 17 and that fits loosely into the circumferential groove 5 of the piston rod 4.

Next, in the second example of the stopper 11 shown in FIG. 6, the positions of the notch 17 and the stopper 18 in the first example are reversed left and right,
While opening the stopper portion 18 at one side edge of the substrate 12,
The notch portion 17 is provided in series at the inner end of the stopper portion 18.

A third example of the stopper 11 shown in FIG. 7 is such that the stopper portion 18 in the second example is not opened at the side edge of the substrate 12 and the rigidity of the stopper 11 is increased.

The fourth example of the stopper 11 shown in FIG.
The recessed portions 15 and 16 provided in the are formed in a square shape.

A fifth example of the stopper 11 shown in FIGS. 9 to 12 is one in which the stopper portion 18 is formed by a plate 18a and the tip end face of the piston rod 4 is received by this plate 18a so that the pushed state is maintained. And the others are the same as in the first example.

In the fifth example, the circumferential groove 5 is formed on the tip of the piston rod 4.
Therefore, it is possible to reduce the processing cost.

If necessary, the plate 18a may be formed with a guide portion 18b for accommodating the tip of the piston rod 4.

In any of the examples, the stopper 11 may be formed by pressing a steel plate, or may be formed by using resin or the like.

The autotensioner of the present invention has the above-mentioned structure, and the use of the stopper 11 will be described based on the first and fifth examples.

One recessed portion 15 is elastically engaged with the inside of the circumferential groove 3 of the cylinder 2 with respect to the tensioner 1 when it is a single unit before being mounted on the engine, and the stopper 11 is attached to the cylinder 2.

At this time, as shown in FIGS. 2 and 12, the cutout portion 17 is externally fitted to the piston rod 4.

Next, the piston rod 4 is pushed in, the stopper 11 is pushed in the radial direction of the cylinder 2, and the other recessed portion 16 is engaged with the circumferential groove 3.

In this state, in the first example, the stopper portion 18 engages with the circumferential groove 5 of the piston rod 4 as shown in FIGS. 3 and 4, and the pushed state of the piston rod 4 is maintained.

Further, in the fifth example, as shown in FIGS. 9 and 10, the plate 18a of the stopper portion 18 supports the tip end surface of the piston rod 4, whereby the pushed state is maintained.

After mounting the tensioner 1 on the engine, the stopper 11 is moved to engage one of the recessed notches 15 with the circumferential groove 3 of the cylinder 2, so that the stopper 18 is separated from the piston rod 4 and the notch 17 is removed. Since it faces the rod 4, the piston rod 4 can be moved to the projecting position as shown in FIGS. 1 and 11, and functions as an auto tensioner.

〔effect〕

As described above, according to the present invention, the stopper is provided with two sets of concave recesses that fit into the circumferential groove of the cylinder, and the stopper base plate allows the protrusion of the piston rod and the push-in state of the rod. Since the stopper part that holds the cylinder is provided, it is only necessary to machine the circumferential groove on the cylinder, which reduces the machining cost and eliminates the need to align the cylinder and piston rod with each other, making piston setting work easy. .

Further, the stopper can be always attached to the cylinder, which is convenient for resetting.

Furthermore, since it is only necessary to provide a circumferential groove on the outer circumference of the cylinder,
The length of the tip of the cylinder and piston rod can be shortened, and the auto tensioner can be downsized.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing a first example of an autotensioner according to the present invention, FIG. 2 is a side view of the same, and FIG. 3 is a front view showing a pushing state of a piston rod in the same.
The figure is a side view of the same, FIG. 5 is a perspective view of a stopper used therein, FIG. 6 is a perspective view of a second example of the stopper, and FIG. 7 is a perspective view of the third example of the same. Is a perspective view showing the fourth example of the same, FIGS. 9 to 12 are explanatory views of the usage state showing the fifth example of the stopper, and FIG. 13 is an explanatory view showing the usage state of the automatic tensioner. FIG. 14 is a vertical sectional front view showing a conventional auto tensioner, and FIG. 15 is a side view of the same. 1 ... Auto tensioner, 2 ... Cylinder, 3 ... Circumferential groove, 4 ... Piston rod, 5 ... Circumferential groove, 11 ... Stopper, 12 ... Substrate, 13 ... Counter plate, 14 ... Bend Pieces, 15, 16 …… Recessed notch, 17 …… Notched, 18 …… Stopper.

Claims (1)

[Scope of utility model registration request] 1. An automatic tensioner for a belt, which interlocks with an idler pulley engaged with a belt for transmitting power of an engine and applies tension to the belt, wherein a peripheral groove is formed on an outer peripheral surface of an opening end portion of a cylinder, and a substrate is provided. And a stopper formed by providing a pair of opposed plates fitted to the open ends of the cylinders at both ends of the cylinder and bending pieces elastically fitted to the circumferential groove at the tip edges of the opposed plates. Two sets of positioning recessed portions are provided side by side, which are selectively fitted and engaged with each other while being elastically expanded and guided to the peripheral groove, and one recessed portion is engaged with the peripheral groove on the substrate. When the notch part that allows the piston rod to slip out is located at the position corresponding to the tip of the piston rod, and the piston rod is slipped out at the position that corresponds to the tip of the piston rod when the other recessed part is engaged with the circumferential groove. The provision of a stopper to prevent Auto tensioner belt to butterflies.