JPS61294250A - Hydraulic adjuster device - Google Patents

Abstract

PURPOSE:To simplify construction of a hydraulic adjuster by forming both an annular groove and an oil release groove extending to a pressure chamber side on the periphery of a piston and arranging a piston ring in the annular groove. CONSTITUTION:A piston 2 contacting a piston rod 5 is arranged in a cylinder 1 of a hydraulic adjuster device. On the periphery of the piston 2, a piston ring groove 2b and a cut groove 2c extending from the groove 2b to a pressure chamber 3 side. A piston ring 8 arranged in the piston ring groove 2b in contact with wall surfaces of the said groove 2b serves as a check valve to prevent oil from flowing from the pressure chamber 3 to a reservoir chamber 10. This eliminates the need for arranging a check valve in the piston 2 and results in the simplification of the hydraulic adjuster device construction.

Description

[Detailed description of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic adjuster device used in an automatic tension-job device for a valve train and a cam drive timing bell 1 in an automobile engine. [Prior Art] A fixed tensioner is generally used to adjust the tension of a timing belt for driving a cam in an automobile engine, and a fixed tensioner is simply applied to the belt at the time of initial setting, and the subsequent automatic adjustment mechanism etc. There are some things that are not provided. For this reason, especially in the case of a crankcase made of aluminum alloy, the difference in thermal expansion between the crankcase and the timing belt causes the tension to loosen, causing tooth skipping when the cam is driven. Moreover, when the temperature rises, excessive tension causes noise generation and a decrease in belt durability. Especially the series overhead cam opposed engine and vIJ! It's the engine...
However, when driving two or more camshafts with a single timing belt, or when driving a water pump, oil pump, etc., an automatic tensioning device is recommended due to the durability of the belt. is necessary. Therefore, there have been many proposals for automatic tension control devices in the past, such as those in which a tension pulley is pushed in the direction of belt tension by a spring force and absorbs the reaction force resulting from fluctuations in belt tension caused by fluctuations in cam driving force, or Hydraulic adjuster devices that utilize the viscosity of oil are known in order to prevent vibrations of tension boots. Examples of the structure of the hydraulic adjuster device include the one shown in Japanese Utility Model Application No. B7-155350, or the one shown in FIG. 4. That is, the hydraulic adjuster device shown in FIG.
0 is closed by a sealing plate 22, and an oil seal 22a is provided between the rod 28 and the sealing plate 22. A pressure chamber 23 is formed between the bottomed side of the cylinder 20 and the piston 21 by filling it with oil. The hydraulic pressure generated in the pressure chamber 23 supports the impulsive reaction force generated in the tension pump 924. Furthermore, when the tension increases due to thermal expansion, oil escapes into the 1F-bar chamber 25 through the gap between the piston 21 and the cylinder 20, and the piston 21 gradually moves in the direction of reducing the tension to the set value. On the other hand, when the tension decreases below the set value, the spring force of the spring 26 causes the piston 2 to
1 moves in the tensioning direction, but due to the check ball 21 shown in the figure, the oil quickly moves from the reservoir chamber 25 to the pressure chamber 23, and the pressing force by the spring 26 is always kept constant. Here, the 1 arbor chamber 2
In many cases, an air pocket or a bellows 29 is provided within the chamber 5. In addition, the reference numeral 30 in the figure is a crankshaft, and 31
is a camshaft pulley, and 32 is a timing belt.

Problems to be Solved by the Invention] However, in any case, the conventional hydraulic adjuster device described above has a complicated structure and is expensive, and the piston rod 28 and sealing plate 22
When the tension arm 33 swings, the oil seal 22a between the piston ring 22a generates friction between the screw 1 and the rod 28, causing a change in the axis of the piston ring 28, creating an operating resistance, and causing the oil seal 22a to rotate. There was a problem that sufficient durability could not be obtained. In addition, the #4 control of the speed when the piston returns against the pressure in the pressure chamber is achieved by the resistance of the fluid flowing through the gap between the screws 1 and the cylinder, and the damper characteristics are adjusted to the required value. In order to keep it within this range, there are difficulties such as the large number of man-hours required to process the gap to the set value, and the difficulty of maintaining accuracy in machining the seat surface of the check ball. Be smart, Cos! ~ There was a problem of getting high. The present invention was made in view of the above-mentioned circumstances, and
It is an object of the present invention to provide a hydraulic adjuster device that has a simple structure, eliminates highly accurate machined parts, and can maintain sufficiently satisfactory performance. [Means for Solving the Problems 1] In order to achieve the above object, the present invention provides a cylinder with a screw 1.
In an apparatus in which a pressure chamber and a 1F-bar chamber are provided in the cylinder by the screw 1-n, an annular groove and an oil relief groove are formed on the outer periphery of the screw 1-n,
A piston ring is disposed in the annular groove, and the oil in the pressure chamber and the reservoir chamber is configured to flow and close through the annular groove and the oil relief groove. [Function] Based on the above configuration, the present invention generates high hydraulic pressure in the pressure chamber when force acts on the hydraulic adjuster device,
This oil pressure acts on the piston ring via the oil relief groove and the annular groove to prevent oil from flowing out of the pressure chamber. On the other hand,
When the force acting on the hydraulic adjuster device decreases, the oil in the IF chamber will migrate to the pressure chamber through the annular groove and the oil relief groove.

【Example】

DESCRIPTION OF THE PREFERRED EMBODIMENTS The hydraulic adjuster device according to the present invention will be explained in detail below with reference to FIGS. 1 to 3. In the figure, reference numeral 1 is a cylinder, and 2 is a piston that slides inside. One side of the cylinder 1 is closed, and the inside together with the piston 2 is filled with oil to form a pressure chamber 3. End surface 4 of the piston 2 opposite to the pressure chamber
A hemispherical concave receiving part 2a is formed in the tensicon arm 7, and the other end of the rod 5 is in contact with a hemispherical concave receiving part 2a, which is in contact with one end of a rod 5 whose both ends are semispherical. An impactful reaction force generated on the tension pulley 6 when it comes into contact with the portion 7 a is transmitted to the other end of the rod 5 via the tension arm 7 . The outer circumferential surface of the piston 2 has a predetermined clearance between it and the cylinder 1, which is slightly larger than conventional ones, and the outer circumferential surface of the piston 2 has an annular screw 1 and a ring 2b having a predetermined width. A stone ring 8 is fitted into the piston ring groove 2b so that the piston ring 8 can move within the piston ring s2b as the piston 2 slides. Note that the screw 1 and the cylinder 8 have a predetermined size and have zero clearance when fitted into the piston ring groove 2b. Furthermore, at least one notch groove 20 is formed along the axial direction from the piston cylinder groove 2b formed in the piston 2 toward the pressure chamber 3 side. A spring 9 is installed in the pressure chamber 3 in a direction that pushes the piston 2 to the left in the figure, and a reliever chamber 10 filled with oil is located on the opposite side of the piston 2 from the pressure chamber 3. The open end of the IJ"-bar chamber 10 is closed by a flexible bellows 11. Here, the outer periphery of the bellows 11 is
The inner circumference of the bead 11 is fixed to the outer circumference of the rod 5. Therefore, in the hydraulic adjuster tiM configured as described above, when an impactful reaction force from the timing belt 12 acts on the screws 1 to 2 from the tension pulley 6 via the rod 5, the As shown, a high hydraulic pressure is generated in the pressure chamber 3 due to the pushing force of the piston 2 to the right side in the figure, and this hydraulic pressure is applied to the surface 8a of the piston ring 8.
The surface 8b of the piston ring 80 is pressed against the surface 2e of the piston cylinder groove 2b, and even if the clearance between the piston 2 and the cylinder 1 is somewhat large, the piston ring 8 provides a sufficient seal. In this case, the timing belt 1 has a sufficiently small gap between pistons.
The high oil pressure in the pressure chamber 3 is maintained against the impact reaction force of 2. Also, when the tension of the timing belt increases slowly due to thermal expansion of the engine, the oil pressure in the pressure chamber 3 increases, and the piston ring 8 acts in the same way, but the joint gap is set to a predetermined size for the required leakage amount. As a result, the oil from the pressure chamber 3 slowly flows out into the reliever chamber 10 through the gap between the piston rings 8 and the tension is lowered to a predetermined pressure defined by the spring 9. On the other hand, if the above belt tension decreases,
As shown in FIG. 3, the piston 2 is pushed back by the reaction force of the spring 9 within the pressure chamber 3, and a constant tension is applied to the timing belt 12 via the rod 5 and tension pulley 6. At this time, the inside of the pressure chamber 3 becomes negative pressure, the piston ring 8 moves to the right in the figure, and the oil passes through the clearance between the piston 2 and the cylinder 1, and the gap between the piston ring 8 and the screw 1-cylinder 8. Inside 8
C, passes through the notch i2c, and moves all the way from the IF nippet chamber 10 into the pressure chamber 3. Note that in the above configuration, the piston ring 8 is connected to the cylinder 1.
In addition to sealing the clearance between the piston 2 and piston 2, it also functions as a damper due to the gap between the piston and cylinder of the conventional structure when the gap is 0, and also functions as the check ball of the conventional structure when the gap is 0 and the notch is full. The bellows 11 absorbs the deviation from the cylinder axis caused by the movement of the rod 5 in the tension adjustment direction and the displacement of the tension arm 7, and also absorbs the relief air 11 caused by the sliding of the rod 5.
) to absorb changes in volume. Further, the outside of the bellows 11 is protected from dust by a dust cover 13. In addition, the reference numeral 14. is the crankshaft, 15 is the crankshaft pulley, 16 is the camshaft, 1
1 indicates the camshaft boob.

【Effect of the invention】

As explained above in detail, the hydraulic adjuster device of the present invention can prevent changes in tension due to the difference in coefficient of thermal expansion with the case when using a cam drive timing belt, wear of the belt, etc. It is possible to realize an automatic tensioner that can prevent a decrease in initial tension and always provide constant tension. In addition, it can be manufactured easily with a simple structure requiring few processing steps, and has sufficient durability.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the hydraulic adjuster device according to the present invention, and FIG.
FIG. 3 is a cross-sectional view of the mounting part showing a case where the belt tension is reduced in the present invention, and FIG.
<It is a sectional view of the hydraulic adjuster device. 1... Cylinder, 2... Piston, 2b... Piston ring groove, 2C... Notch groove, 3... Pressure chamber,
5...Orad, 6...Tension pulley, 7...
Tension arm, 8...Piston ring, 9...
Spring, 10...S+P louver, 11...Bellows, 12...Timing belt. Patent Applicant Tomito Heavy Industries Co., Ltd. Agent On Patent Attorney Atsushi Kobashi Atsushi On Patent Attorney
Susumu Murai □−−ノ

Claims (1)

[Claims] In a device in which a piston is fitted into a cylinder and a pressure chamber and a reliever chamber are formed in the cylinder by the piston, an annular groove and an oil relief groove are formed on the outer periphery of the piston, and a piston ring is disposed in the annular groove. The hydraulic adjuster device is characterized in that the oil in the pressure chamber and the reliever chamber flows through the annular groove and the oil relief groove and is closed.