JP2004339976A - Piston ring tension regulator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device with a simple configuration capable of appropriately adjusting tension of an oil ring provided to the outer periphery of a piston reciprocating in the cylinder of an internal conbustion engine in accordance with the operating state of the engine. <P>SOLUTION: A piston ring tension regulator 10 pushes an oil ring 5c from the inside of piston 3 toward the outer periphery (the inner wall of a cylinder 4). In the configuration, the strength of the thrust (tension of the oil ring 5c) is regulated in accordance with the operating state of an engine 100. The piston ring tension regulator 10 contains as components an annular oil passage 11 formed in a piston 3, a thrust applying mechanism 20 for pushing the oil ring 5c toward the outer periphery of the piston 3 on the basis of the pressure of the oil supplied to the annular oil passage 11, an ejecting mechanism 30 for gushing oil force-fed from an oil pump to be led in the annular oil passage 11, or the like. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a device for variably adjusting the tension of a piston ring provided in a gap between a cylinder of an internal combustion engine and an outer periphery of a piston reciprocating in the cylinder.
[0002]
[Prior art]
As is well known, a plurality of piston rings are provided in a gap between a cylinder of an internal combustion engine (hereinafter, referred to as an engine) and an outer periphery of a piston reciprocating in the cylinder. The piston ring is mounted in a circumferential groove formed on the outer circumference of the piston.
[0003]
For example, an oil ring, which is a kind of piston ring, plays a role of scraping lubricating oil existing between a cylinder and a piston.
[0004]
The efficiency with which the oil ring scrapes off the lubricating oil existing between the cylinder and the piston is often determined by the magnitude of the force (tension of the piston ring) by which the oil ring presses the inner peripheral surface of the cylinder.
[0005]
Here, in order to maintain a good operating state of the engine, it is necessary to supply a larger amount of lubricating oil between the cylinder and the piston as the engine speed increases. As the amount of lubricating oil supplied between the cylinder and the piston increases, the oil ring is required to have a more efficient ability to scrape off the lubricating oil.
[0006]
For example, Patent Literature 1 discloses a technique in which working oil is guided into a piston through oil passages formed in a crankshaft and a connecting rod, and the tension of an oil ring is adjusted by the pressure of the working oil. Further, in Patent Document 2, the tension of the piston ring is adjusted by forming a piston ring of a magnetic material, embedding a stator coil that generates an electromagnetic force by energization in an inner wall of the cylinder, and performing energization control on the stator coil. The technology is described.
[0007]
[Patent Document 1]
JP-A-6-123357 [Patent Document 2]
JP 2001-200752 A [Problems to be Solved by the Invention]
However, in the technique described in Patent Document 1, a path for transmitting hydraulic oil (oil pressure) is too long, and sufficient responsiveness is required to obtain a piston tension corresponding to an operating state of the engine. Is difficult. Further, according to the technology described in Patent Document 2, sufficient responsiveness can be ensured, but a complicated hardware structure and software structure are required. Soar.
[0008]
The present invention has been made in view of such circumstances, and an object of the present invention is to change the tension of an oil ring provided on the outer periphery of a piston reciprocating in a cylinder of an engine to an operating state of the engine. An object of the present invention is to provide a device having a simple configuration that can be appropriately adjusted according to the conditions.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides
(1) A device for adjusting the tension of a piston ring mounted in an outer circumferential groove of a piston reciprocating in a cylinder of an internal combustion engine, wherein an oil passage formed inside the piston and an oil supplied to the oil passage are provided. A pressing force applying means for pressing the piston ring from the inside of the piston toward the outer periphery of the piston based on the pressure of the oil, and an ejection mechanism for ejecting the oil to be fed and introducing the oil into the oil passage. That is the gist.
[0010]
According to this configuration, the tension adjustment of the piston ring according to the operating state of the engine can be accurately performed using a simple configuration.
[0011]
(2) Preferably, a pump is provided for pumping oil to the ejection mechanism in mechanical linkage with the rotation of the internal combustion engine.
[0012]
According to this configuration, the tension of the piston ring can be accurately adjusted according to the engine speed of the engine.
[0013]
(3) Preferably, the oil passage formed inside the piston is an annular oil passage formed along the circumferential direction of the piston.
[0014]
According to this configuration, for example, an oil pressure for adjusting the tension of the piston ring can be supplied by diverting an existing oil passage provided for cooling the piston. Therefore, the manufacturing process can be further simplified, and the manufacturing cost can be further reduced.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
(First Embodiment)
Hereinafter, a first embodiment of the present invention will be described.
[0016]
[Structure of piston ring tension adjusting device]
FIG. 1 is a schematic diagram showing a main structure of a piston ring tension adjusting device according to the present embodiment.
[0017]
In FIG. 1, an internal combustion engine (hereinafter simply referred to as an engine) 100 burns a mixture of fuel and air in a combustion chamber 1. The piston 3 connected to one end of the connecting rod 2 is reciprocated in the cylinder 4 by the combustion energy generated at this time, and a crankshaft (not shown) connected to the other end of the connecting rod 2 is rotated.
[0018]
Three peripheral grooves are formed on the outer periphery of the piston 3. Piston rings 5a, 5b, 5c are mounted on the respective circumferential grooves 3a, 3b, 3c. The piston ring (first compression ring) 4a closest to the crown 2d (combustion chamber 1) of the piston 3 mainly suppresses the amount of blow-by gas leaking from the combustion chamber 1 to the crankcase (accommodating space for the crankshaft) 7. It has a function to do. The piston ring (oil ring) 5c closest to the crankcase 7 mainly has a function of scraping off oil (lubricating oil) supplied to a gap (sliding portion) between the piston 3 and the cylinder 4. The second compression ring 5b arranged between the first compression ring 5a and the oil ring 5c has the functions of both rings 5a and 5c (suppression of the amount of blow-by gas and scraping of oil).
[0019]
The piston ring tension adjusting device 10 of the present embodiment pushes the oil ring 5c from the inside of the piston 3 toward the outer periphery (the inner wall of the cylinder 4), and furthermore, determines the magnitude of the pushing force (the tension of the oil ring 5c) by the engine. It has a function of adjusting according to the operation state of the 100. The piston ring tension adjusting device 10 includes an annular oil passage 11 formed inside the piston 3, and an oil ring 5 c extending from the inside of the piston 3 toward the outer periphery of the piston 3 based on the pressure of oil supplied to the annular oil passage 11. The main components include a pressing force applying mechanism 20 that presses the oil, an ejection mechanism 30 that ejects oil pumped from an oil pump (not shown) and introduces the oil into the annular oil passage 11. The oil supplied to the annular oil passage 11 has a function of cooling the piston 3 in addition to the function of the pressing force applying mechanism 20.
[0020]
The ejection mechanism 30 includes a pressure accumulation oil passage 31, an ejection pipe 32, a check valve 33, and the like. The accumulator oil passage 31 is formed in the cylinder block 6 of the engine 100, and transfers oil pumped from an oil pump. The ejection pipe 32 is disposed in the crankcase 7 and has an oil ejection port 32 a facing the piston 3 in the cylinder 4. The check valve 33 is provided at a communication portion C between the pressure accumulation oil passage 31 and the ejection pipe 32, and opens only when the oil pressure in the pressure accumulation oil passage 31 exceeds a predetermined value. The pressure accumulation oil passage 31 is provided with a well-known relief valve (not shown). The relief valve opens when the oil pressure in the pressure accumulation oil passage 31 exceeds a preset upper limit value (relief pressure), and releases the oil in the passage 31 to the outside. Due to the function of the relief valve, the oil pressure in the passage 31 does not significantly exceed the relief pressure.
[0021]
FIG. 2 is an enlarged view showing the vicinity of the pressing force applying mechanism 20. The pressing force applying mechanism 20 includes a ring support member 21c, a rod 22c, a coil spring 24c, a pressure receiving plate 23c, a spring housing 25c, and the like. The rod 22c is reciprocally supported in a hole 8c formed through the piston 3 from the bottom of the circumferential groove 3c to the annular oil passage 11. A ring support member 21c is fixed to one end of the rod 22 (the end of a portion protruding into the circumferential groove 3c). The ring support member 21c supports the oil ring 5c at the bottom of the circumferential groove 3c. A pressure receiving plate 23c is fixed to the other end of the rod 22c (the end of a portion protruding into the annular oil passage 11). A coil spring 24c is attached to the outer periphery of a portion of the rod 22c protruding into the annular oil passage 11, and urges the pressure receiving plate 23c from the outer periphery of the piston 3 toward the annular oil passage 11. The cylinder 4 is attached to the inner wall of the annular oil passage 11 so as to house a part of the rod 22c (a portion protruding into the annular oil passage 11), the pressure receiving plate 23c, and the coil spring 24c. When the oil pressure in the annular oil passage 11 increases, the oil pressure acts on the pressure receiving plate 23c from the open end of the housing 25c, and overcomes the urging force of the coil spring 24c to move the rod 22 from the inside of the piston 3 toward the cylinder inner wall 6a. push. As a result, the oil ring 5c is pressed against the cylinder inner wall 6a (the tension of the oil ring 5c increases).
[0022]
Although one pressing force applying mechanism 20 functions, a plurality of pressing force applying mechanisms 20 are preferably provided along the circumferential groove of the piston 3.
[0023]
The annular oil passage 11 is provided with an oil introduction passage 11a and a discharge port (not shown). The arrangement of the introduction passage 11a and the ejection port 32a of the ejection tube 32 is set so that the oil ejected from the ejection tube 32 is introduced into the annular oil passage 11 from the introduction passage 11a.
[0024]
[Function of piston ring tension adjustment device]
Next, the function of the piston ring tension adjusting device 10 having such a configuration will be described. In the piston ring tension adjusting device 10 of the present embodiment, the magnitude of the pump function of the oil pump (the oil pressure in the pressure accumulating oil passage 31) changes according to the rotational speed (engine speed) NE of the engine 100. When the oil pressure in the pressure accumulating oil passage 31 changes, the flow rate of oil ejected from the ejection port 32a of the ejection pipe 32 and, consequently, the oil pressure in the annular oil passage 11 change. Then, the pressing force applying mechanism 20 presses the oil ring 5c against the cylinder inner wall 6a according to the oil pressure in the annular oil passage 11. That is, the tension of the oil ring 5c is increased according to the engine speed NE.
[0025]
FIG. 3 shows the relationship between the engine speed NE and the tension of the oil ring 5c. As shown by the solid line in FIG. 3, when the engine speed NE is equal to or less than the predetermined value NE1, the check valve 33 is not opened because the oil pressure in the accumulator oil passage 31 is low, and the annular oil passage 11 Is not supplied to the oil ring 5c, the tension of the oil ring 5c becomes an extremely low value (the increase in the tension due to the operation of the pressing force applying mechanism 20 becomes "0"). When the engine speed NE exceeds a predetermined value, oil is supplied from the ejection pipe 32 to the annular oil passage 11, and the oil pressure in the annular oil passage 11 increases as the engine speed NE increases. Then, as the oil pressure in the annular oil passage 11 increases, the tension of the oil ring 5c increases.
[0026]
As described in the related art, the higher the engine speed NE, the higher the performance required for the oil ring 5c (the performance of scraping off the lubricating oil between the piston 3 and the cylinder 4). Therefore, as shown by a dashed line in FIG. 3, in a conventional engine having no function of changing the tension of the oil ring 5c, the tension of the oil ring 5c corresponds to the maximum value NEMAX of the engine speed NE. Must be set (strongly). On the other hand, as the tension of the oil ring 5c increases, the friction between the oil ring 5c and the cylinder 4 also increases. For this reason, when the tension of the oil ring 5c is set to be relatively high, the mechanical loss accompanying the operation of the engine increases under the condition that the engine speed NE is low.
[0027]
In this regard, according to the present embodiment, the tension of the oil ring 5c can be accurately adjusted according to the engine speed NE by utilizing the pressure of the oil pumped from the oil pump.
[0028]
Further, since a simple configuration (the pressing force applying mechanism 20) is used to convert the oil pressure into the tension of the oil ring 5c, the manufacturing process is not complicated.
[0029]
Further, the oil passage for transmitting the oil pressure for operating the pressing force applying mechanism 20 is short, and its structure is not complicated. Therefore, the response of the change in the tension of the oil ring 5c to the change in the engine speed NE is also high.
[0030]
In particular, in the present embodiment, as a part of the piston ring tension adjusting device 10, an annular oil passage 11 originally formed in the piston 3 for cooling the piston 3, and cooling oil is supplied to the annular oil passage 11. The oil passage structure for supplying is diverted. Also in this respect, the manufacturing process is not complicated and the manufacturing cost is low.
[0031]
Moreover, by using the pressure of the cooling oil of the piston 3 whose circulation efficiency (flow rate) increases in accordance with the engine speed NE for adjusting the tension of the oil ring 5c, appropriate tension adjustment corresponding to the engine speed NE can be performed. Done.
[0032]
Further, there is no need for precise energization control for driving an actuator (corresponding to the pressing force applying mechanism 20) for adjusting the tension of the oil ring 5c.
[0033]
In particular, in an engine system that repeatedly starts and stops the internal combustion engine, such as an internal combustion engine that implements a so-called idle stop or a hybrid engine that obtains a driving force of a vehicle or the like by cooperation of a motor and an internal combustion engine, the motor uses a motor. Frequently restart the internal combustion engine. If the oil ring tension adjusting device 10 according to the present embodiment is adopted in such an engine system, the tension of the oil ring (the coefficient of static friction of the oil ring with respect to the inner wall of the cylinder) when the internal combustion engine is started (under a condition where the engine speed is low) And dynamic friction coefficient) can be set to extremely small values. As a result, the fuel efficiency of the internal combustion engine can be improved. It is also possible to reduce the size of the motor used for starting the internal combustion engine.
[0034]
(Second embodiment)
Hereinafter, a second embodiment embodying the present invention will be described focusing on differences from the first embodiment. Note that among the constituent members of the second embodiment, those having the same structure and function as those of the first embodiment are denoted by the same reference numerals, and redundant description is omitted here.
FIG. 4 is an enlarged view showing the vicinity of a pressing force applying mechanism which is a part of the piston ring tension adjusting device of the present embodiment. As shown in FIG. 4, the piston ring tension adjusting device according to the present embodiment includes a pressing force applying mechanism (first embodiment) including a ring support member 21b, a rod 22b, a pressure receiving plate 23b, a coil spring 24b, a spring housing 25b, and the like. Having substantially the same structure as the pressing force applying mechanism 20 according to the first embodiment) as means for adjusting the tension of the second compression ring 5b. The oil ring 5c is accommodated in the circumferential groove 3c while being supported by the annular support member 22c '.
In the present embodiment, the pressing force applying mechanism presses the oil ring 5c against the cylinder inner wall 6a according to the oil pressure in the annular oil passage 11. That is, the tension of the second compression ring 5b is increased according to the engine speed NE.
(Third embodiment)
Hereinafter, a third embodiment embodying the present invention will be described focusing on differences from the first and second embodiments. Note that among the constituent members of the third embodiment, those having the same structure and function as those of the first and second embodiments are denoted by the same reference numerals, and redundant description is omitted here. I do.
[0035]
The piston ring tension adjusting device according to the third embodiment has a function of adjusting the tension of both the second compression ring and the oil ring according to the operating state of the engine.
[0036]
FIG. 5 is an enlarged view showing the vicinity of a pressing force applying mechanism which is a part of the piston ring tension adjusting device of the present embodiment. As shown in FIG. 5, the piston ring tension adjusting device of the present embodiment includes two pressing force applying mechanisms. The first pressing force applying mechanism includes a ring support member 21b, a rod 22b, a pressure receiving plate 23b, a coil spring 24b, a spring housing 25b, and the like, and adjusts the tension of the second compression ring 5b. The second pressing force applying mechanism includes a ring support member 21c, a rod 22c, a pressure receiving plate 23c, a coil spring 24c, a spring housing 25c, and the like, and adjusts the tension of the oil ring 5b. The oil supplied from the ejection pipe 32 (see FIG. 1) is introduced into the annular oil passage 11 through the introduction passage 11a, and acts on the pressure receiving plates 23b and 23c of both the pressing force applying mechanisms. As a result, the first pressing force applying mechanism presses the second compression ring 5b, and the second pressing force applying mechanism presses the oil ring 5c against the cylinder inner wall 6a. That is, the tension of both the second compression ring 5b and the oil ring 5c is increased according to the oil pressure (the engine speed NE) in the annular oil passage 11.
[0037]
By changing the areas of the pressure receiving plates 23b and 23c, the urging forces of the coil springs 24b and 24c, the shape of the passage 11a, and the like, the characteristic of the tension change of the second compression ring 5b corresponding to the engine speed NE and the engine rotation The characteristic of the tension change of the oil ring corresponding to several NEs can be individually changed. As described above, according to the third embodiment, basically, a single oil pressure transmission path (a path from an oil pump to a piston introduction passage 11a) is used, and a plurality of piston rings (this embodiment) are used. In the embodiment, the tension of the second compression ring 5b and the oil ring 5c) can be adjusted together.
[0038]
Incidentally, in addition to the above-described embodiments, a configuration in which a mechanism equivalent to the pressing force applying mechanism according to the above-described embodiments is provided as means for adjusting the tension of the first compression ring 5a, the circumferential grooves 3a, 3b, The present invention is embodied by adopting various device configurations such as a configuration in which a support plate is provided on all the bottoms of 3c and oil pressure is directly applied to each support plate to adjust the tension of each of the piston rings 5a, 5b, 5c. Can be
[0039]
In each of the above embodiments, the oil pressure is supplied to the pressing force applying mechanism using an oil pump that is mechanically linked to the rotation of the engine 100. On the other hand, for example, by using an electric oil pump or the like, it is also possible to adopt a device configuration that freely controls the oil pressure supplied to the pressing force applying mechanism. In this case, the oil pressure supplied to the pressing force applying mechanism is adjusted according to not only the engine speed NE but also other parameters that reflect the operating state of the engine 100 (eg, load, torque, output, etc. of the engine 100). it can.
[0040]
【The invention's effect】
As described above, according to the present invention, appropriate tension adjustment of the piston ring can be performed in accordance with the operating state of the engine without incurring a complicated manufacturing process and an increase in manufacturing cost.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a main structure of a piston ring tension adjusting device according to a first embodiment of the present invention.
FIG. 2 is an enlarged view of a part (near a pressing force applying mechanism) of the piston ring tension adjusting device of the embodiment.
FIG. 3 is a diagram showing a relationship between an engine speed and an oil ring tension when the piston ring tension adjusting device of the embodiment is used.
FIG. 4 is an enlarged view of a part (near a pressing force applying mechanism) of a piston ring tension adjusting device according to a second embodiment of the present invention.
FIG. 5 is an enlarged view of a part (near a pressing force applying mechanism) of a piston ring tension adjusting device according to a third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Combustion chamber 2 Connecting rod 2d Head 3 Piston 3a, 3b, 3c Circumferential groove 4 Cylinder 5a First compression ring (piston ring)
5b 2nd compression ring (piston ring)
5c Oil ring (piston ring)
Reference Signs List 6 Cylinder block 6a Cylinder inner wall 7 Crank case 8c Hole 10 Piston ring tension adjusting device 11 Annular oil passage 11a Introductory passage 11b Passage 20 Push force applying mechanism (press force applying means)
21b, 21c Supporting plates 22b, 22c Rods 23b, 23c Pressure receiving plates 24b, 24c Coil springs 25b, 25c Housing 30 Injection mechanism 31 Accumulated oil passage 32 Injection tube 32a Injection port 33 Check valve 100 Engine C communication section

Claims (3)

An apparatus for adjusting the tension of a piston ring mounted on an outer peripheral groove of a piston that reciprocates in a cylinder of an internal combustion engine,
An oil passage formed inside the piston,
Pressing force applying means for pressing the piston ring from the inside of the piston toward the outer periphery of the piston based on the pressure of the oil supplied to the oil passage;
An ejection mechanism for ejecting oil to be pumped and introducing the oil into the oil passage;
A piston ring tension adjusting device comprising: The piston ring tension adjusting device according to claim 1, further comprising a pump that pumps oil to the ejection mechanism in mechanical linkage with rotation of the internal combustion engine. 3. The piston ring tension adjusting device according to claim 1, wherein the oil passage formed inside the piston is an annular oil passage formed along a circumferential direction of the piston.

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