JP2006337164A - Method for measuring sliding surface shape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for measuring sliding surface shape, capable of accurately measuring the shape of circumferential sliding surface on piston ring generating torsion, at use. <P>SOLUTION: In this method for measuring sliding surface shape for measuring the shape of the circumferential sliding surface which is a part sliding along a cylinder wall of the piston ring, having an inside deficient part formed by cutting down the upper surface 4 inside end of the piston ring 1, comprising the circumferential sliding surface 2, the upper and lower surfaces and the inner circumferential surface and forming an approximately circular shape, when an abutment joint is closed, and inserted into a piston ring groove in a state of being in oblique contact with the cylinder wall by the torsional action by the inside deficiency part, the shape of the circumferential sliding surface of the piston ring is measured, in a state of the lower surface 5 which is a surface on the crank case side of the piston ring, being arranged in close contact with a plane and the piston ring is in close contact therewith. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a sliding surface shape measuring method for measuring the shape of the outer peripheral sliding surface of a piston ring that causes twisting during use.

  In recent years, with the improvement of engine performance, piston rings are required to prevent blow-by gas and reduce the consumption of lubricating oil for the purpose of improving fuel efficiency.

  In order to improve the sealing performance of the piston ring in response to such a demand, a piston ring that generates twist during use has been developed. Since this piston ring has an inner defect part that is cut off on the inner side of the upper side surface of the piston ring, and twisting occurs during use due to the twisting action in the inner defect part, as shown in FIG. Except during the explosion stroke, the ring posture is inclined with respect to the cylinder wall 20. In such a piston ring, during the explosion stroke of the engine, as shown in FIG. 5B, the explosion pressure acts on the upper surface 44 and the inner peripheral surface 46 of the piston ring 41 as the vertical pressure x and the horizontal pressure y. As a result, the piston ring 41 is pushed down to the lower surface 33 of the piston ring groove 31 and the twist is eliminated, and is pressed against the cylinder wall 20 by the horizontal pressure y and the self-expanding force.

  In such a piston ring that twists during use, the shape of the outer peripheral sliding surface is important for suppressing blow-by and reducing oil consumption. For example, when the outer peripheral sliding surface is rectangular as shown in FIG. 5, the ring posture is in the cylinder hole 20 in a state of being inclined with respect to the cylinder wall 20 as shown in FIG. The oil scraping effect can be enhanced. Further, as shown in FIG. 5 (b), since the entire surface is in close contact with the cylinder wall 20 during the explosion stroke of the engine, the airtightness can be improved.

  Further, Non-Patent Document 1 discloses a piston ring 61 in which the shape of the outer peripheral sliding surface which is a portion in contact with the cylinder wall is a barrel face as shown in FIG. Is disclosed. In this way, in the barrel face type piston ring 61, the shape of the outer peripheral sliding surface 62 does not come into contact with the cylinder wall 20, so that the sliding resistance is reduced and the friction is reduced. Moreover, it has an effect also in improving followability.

  Thus, the shape of the outer peripheral sliding surface of the piston ring is designed along the expected effect. Therefore, naturally, in the manufacturing process of the piston ring, it is required to measure the shape of the actually processed outer peripheral sliding surface and form the outer peripheral sliding surface in a desired shape with high accuracy.

  For example, in a piston ring that twists during use as described above, as a method of measuring the shape of the outer peripheral sliding surface, measurement is performed using a surface shape measuring device such as a contact type or a non-contact type in a twisted state. It is generally done. However, this method has a problem that a slight difference cannot be accurately measured in the shape of the outer peripheral sliding surface that has been processed in a complicated manner, and the accurate shape of the outer peripheral sliding surface cannot be grasped.

"Piston Ring", Editor: Piston Ring Editorial Committee, Publisher: Nikkan Kogyo Shimbun, Publication Date: July 10, 1970, pages 97-99, (6) Barrel Face Type

  The present invention has been made in view of the above-described object, and provides a piston ring sliding surface shape measuring method capable of accurately measuring the shape of the outer peripheral sliding surface of a piston ring that twists during use. This is the main purpose.

  In order to achieve the above object, the present invention comprises an outer peripheral sliding surface, an upper and lower surface, and an inner peripheral surface, and is formed into a substantially circular shape when the joint is closed. The outer peripheral sliding surface that is a portion that slides with the cylinder wall of the piston ring that is fitted in the piston ring groove in a state of being inclined against the cylinder wall from the twisting action by the inner defect portion The shape of the sliding surface for measuring the shape of the piston ring is arranged such that the lower surface, which is the surface on the crank chamber side of the piston ring, is in close contact with a flat surface, and the piston ring is in contact with the piston ring. A method for measuring the shape of a sliding surface of a piston ring, characterized by measuring the shape of an outer peripheral sliding surface.

  In the present invention, the piston ring which is the object of measurement has conventionally been subjected to a method of measuring the shape of the sliding surface in a state per slant. In such a conventional sliding surface shape measuring method, for example, the outer peripheral sliding surface shape of the piston ring is a barrel face type, and the first sliding surface is an outer peripheral sliding surface located on the upper surface side of the piston ring. The barrel apex where the moving surface and the second sliding surface, which is the outer peripheral sliding surface located on the lower surface side of the piston ring, are located on the upper side of the piston ring from the center of the outer peripheral sliding surface in the piston ring axial direction. In the case of the asymmetric barrel face type, it is difficult to accurately measure the shape of the outer peripheral sliding surface (barrel apex position, barrel amount). For example, the torsion angle is large with respect to a small amount of barrel, a small amount of shape difference cannot be detected by measurement, and there is a state where the actual shape in the sliding state cannot be matched with the measured shape. However, in the present invention, since the measurement is performed with the lower surface of the piston ring in close contact with a flat surface, even a sliding surface having the shape described above can be measured accurately. Here, the barrel amount is a value corresponding to the width (C in FIG. 4) of the piston ring outer peripheral sliding surface in the piston ring radial direction.

  In the present invention, the method for measuring the shape of the outer peripheral sliding surface of the piston ring is preferably a stylus type. This is because it is possible to easily measure the accurate sliding surface shape by taking advantage of the effects of the present invention.

  Furthermore, in the present invention, the piston ring has a first sliding surface whose sliding surface is inclined in a curved shape radially inward of the piston ring toward an upper surface which is a combustion chamber side surface of the piston ring, And a second sliding surface inclined in a curved shape radially inward of the piston ring toward a lower surface which is a surface on the crank chamber side of the piston ring, and the first sliding surface and the second sliding surface are The vertex of the barrel to be joined is provided within a range of 5/100 to 33/100 from the upper surface side of the piston ring with respect to the width of the sliding surface in the sliding direction. The width in the ring radial direction is preferably used within a range of 1 to 20 μm.

  Such a sliding surface shaped piston ring has been difficult to accurately measure with the conventional sliding surface shape measuring method, but in the present invention, as described above, the lower surface of the piston ring is in close contact with the flat surface. Since the measurement is performed in the above state, accurate measurement is possible even in the case of the outer peripheral sliding surface having the shape described above. Further, by making the outer peripheral sliding surface have the shape described above, it is possible to suppress blow-by gas and reduce oil consumption. That is, when the explosion pressure generated during the explosion stroke acts on the upper surface and the rear surface of the piston ring as the vertical pressure and the horizontal pressure, the first sliding surface is a region where the horizontal pressure acting radially inward of the piston ring acts. Therefore, the horizontal pressure can be reduced. Therefore, the pressure contact force to the cylinder wall can be maintained high, and blow-by gas can be suppressed. In addition, the oil consumption can be reduced.

  In the piston ring sliding surface shape measuring method of the present invention, for example, the outer peripheral sliding surface shape of the piston ring is a barrel face type, and the barrel apex is the outer peripheral sliding surface in the piston ring axial direction. Even in the case of an asymmetric barrel face type that is located on the upper surface side of the piston ring from the center, there is an effect that the shape of the sliding surface can be accurately measured.

  Hereinafter, the method for measuring the sliding surface shape of the piston ring of the present invention will be described.

  In the piston ring sliding surface shape measuring method of the present invention, the piston ring that is the object of measurement includes an outer peripheral sliding surface, an upper and lower surface, and an inner peripheral surface, and is a substantially circular shape when the joint is closed. The ring has an inner defect part that is cut off at the upper surface inner end of the ring, and is fitted into the piston ring groove in a state of being inclined against the cylinder wall due to the twisting action of the inner defect part.

  Conventionally, in the measurement of the outer peripheral sliding surface shape of the piston ring that causes torsion during use as described above, a method of measuring in a state per inclination has been performed. In such a conventional method for measuring the shape of the outer peripheral sliding surface, for example, the shape of the outer peripheral sliding surface is a barrel face type, and the upper surface which is the surface on the combustion chamber side of the piston ring among the outer peripheral sliding surfaces. The top of the barrel where the first sliding surface located on the side and the second sliding surface located on the lower surface side which is the crank chamber side surface of the piston ring are joined is the center of the outer peripheral sliding surface in the piston ring axial direction In the case of the asymmetric barrel face type positioned on the upper surface side of the piston ring, it was difficult to measure accurately. However, in the present invention, even if the sliding surface has the shape as described above, the measurement can be accurately performed by performing the measurement while the lower surface of the piston ring is in close contact with the flat surface. Here, the plane indicates a measurement table having a plane.

  A method for measuring the sliding surface shape of the piston ring of the present invention having such advantages will be described with reference to the drawings. FIG. 1 is an explanatory view showing an example of a method for measuring a sliding surface shape of a piston ring according to the present invention.

  In the method for measuring the sliding surface shape of the piston ring according to the present invention, as shown in FIG. 1A, the lower surface 5 which is a surface located on the crank chamber side of the piston ring 1 is disposed on the flat surface 10. Then, from this state, as shown in FIG. 1B, the lower surface 5 of the piston ring is brought into close contact with the flat surface 10 by a method such as applying pressure from the upper surface 4 which is the surface located on the combustion chamber side of the piston ring 1. Let them fix. In this state, for example, by using the stylus method 21, the tip of the needle is moved, for example, in the direction indicated by the arrow 22 to trace the surface of the outer peripheral sliding surface 2 and measure the shape of the outer peripheral sliding surface 2. To do.

  As described above, in the present invention, since the shape of the outer peripheral sliding surface is measured with the lower surface of the piston ring being in close contact with the flat surface, accurate measurement is difficult with the conventional sliding surface shape measuring method. Even the outer peripheral sliding surface of the piston ring that twists during use can be measured accurately.

  Hereinafter, the sliding surface shape measuring method of the piston ring of the present invention will be described in detail.

  First, in the piston ring sliding surface shape measuring method of the present invention, the piston ring to be measured consists of an outer peripheral sliding surface, an upper and lower surface, and an inner peripheral surface, and becomes substantially circular when the joint is closed. The upper end of the upper surface of the piston ring has an inner defect portion cut off. Specifically, when fitted in the piston ring groove of the piston, the inner end portion of the surface arranged on the combustion chamber side is cut off and has an inner defect portion. Due to this inner deficit portion, the overall stress balance in the piston ring becomes asymmetrical, so that a twisting action occurs, and the posture of the piston ring in the piston ring groove is inclined with respect to the cylinder wall.

  Such a piston ring in the present invention will be specifically described with reference to the drawings. FIG. 2 is a schematic cross-sectional view showing an example of a piston ring to be measured in the sliding surface shape measuring method of the present invention. FIG. 2 (a) is an explanatory view showing a state in the piston ring groove of the piston ring in the present invention other than at the time of the engine explosion stroke, and FIG. 2 (b) is a diagram at the time of the explosion stroke. It is explanatory drawing which shows the state in the piston ring groove | channel of the piston ring in invention.

  First, as shown in FIG. 2A, the piston ring 1 is fitted and used in a piston ring groove 31 of the piston 30. A combustion chamber (not shown) is located above the piston 30, and a crank chamber (not shown) is located below the piston 30. In the following description, the combustion chamber side may be the upper side and the crank chamber side may be the lower side.

  Such a piston ring 1 has an inner defect 7 whose inner side is cut off on the upper surface 4 which is a surface located on the combustion chamber side of the piston ring 1. Thereby, since the balance of the overall stress in the piston ring 1 becomes asymmetric, a twisting action is generated, and the posture of the piston ring 1 in the piston ring groove 31 comes into contact with the cylinder wall 20 against an inclination.

  In such a piston ring 1, as shown in FIG. 2 (b), when the engine reaches an explosion stroke, the explosion pressure becomes the vertical pressure x and the horizontal pressure y, and the upper surface 4 and the inner peripheral surface 6 of the piston ring 1. Act on. As a result, the piston ring 1 is pushed down by the lower surface 33 of the piston ring groove 31 and the twist is eliminated. As described above, in the piston ring 1 according to the present invention, when the engine is moved from the explosion stroke shown in FIG. 2A to the explosion stroke shown in FIG. The part of the surface 2 moves to the piston ring upper surface 4 side.

  In such a piston ring according to the present invention, the shape of the inner defect portion is formed so that the shape of the inner side of the piston ring is asymmetrical, and is a shape that can cause a twisting action on the piston ring. If there is no particular limitation. Specifically, an inside bevel type as shown in FIG. 2, an inside cut type as shown in FIG. 3 (a), a single-sided keystone type as shown in FIG. 3 (b), an internal step type as shown in FIG. Can be mentioned. Further, as shown in FIGS. 2 (a) and 2 (b), the piston ring according to the present invention has a piston ring upper surface 4 and a piston ring lower surface 5 on the upper and lower ends of the outer peripheral sliding surface 2 of the piston ring 1, and an outer peripheral slide. A curved chamfered portion 8 that connects the moving surface 2 may be provided.

  The present invention is a method for measuring the shape of the outer peripheral sliding surface of such a piston ring. In addition, the outer periphery sliding surface as used in the field of this invention represents the surface which removed the chamfer part of the upper surface and the lower surface in the surface which contact | connects the cylinder wall of an outer peripheral surface of a piston ring.

  In the present invention, first, the lower surface of the piston ring is disposed so as to be in close contact with a flat surface, and the outer peripheral sliding surface shape is measured in this state. At this time, the plane is not particularly limited as long as it can be installed with the lower surface of the piston ring in close contact. For example, it may be a horizontal plane or a plane in the vertical direction. In addition to the surface shape measuring device that measures the shape of the sliding surface, the plane on which the piston ring is installed is appropriately selected.

  Further, in the present invention, arranging the lower surface of the piston ring so as to be in close contact with the flat surface means disposing the twist and arranging the lower surface of the piston ring in contact with the entire surface. Specifically, the method for bringing the piston ring into such a state is not particularly limited. For example, a method of applying pressure from the upper surface of the piston ring, a method of using a fixing jig such as a clamp, a method of attracting by a magnetic force Etc. Among these, it is preferable to perform the measurement so that the twist is eliminated.

  Furthermore, the method for measuring the shape of the sliding surface in the above-described state is not particularly limited, regardless of whether it is a contact type or a non-contact type. Specifically, examples of the contact type include a stylus type. Examples of the non-contact type include an optical method.

  Among them, in the present invention, a stylus type is preferable. This is because it is possible to easily measure the accurate sliding surface shape by taking advantage of the effects of the present invention.

  In such a method for measuring the sliding surface shape of the piston ring according to the present invention, a preferred embodiment as a piston ring to be measured will be described in detail below.

  In the piston ring sliding surface shape measuring method of the present invention, the piston ring that is the object of measurement is such that the outer peripheral sliding surface that slides with the cylinder wall of the piston ring faces the upper surface of the piston ring in the radial direction. A first sliding surface inclined in a curved shape inward, and a second sliding surface inclined in a curved shape radially inward toward the lower surface of the piston ring. The barrel apex to which the two sliding surfaces are joined is provided within a range of 5/100 to 33/100 from the upper surface side of the piston ring with respect to the width in the sliding direction of the outer peripheral sliding surface. The width of the sliding surface in the piston ring radial direction is preferably used within a range of 1 to 20 μm.

  In the case of the outer peripheral sliding surface having such a shape, it has been difficult to accurately measure by the conventional sliding surface shape measuring method, but in the present invention, as described above, the lower surface of the piston ring is By measuring in a state of being in close contact with a flat surface, even the outer peripheral sliding surface having the above shape can be measured accurately.

  In addition, the said numerical value is prescribed | regulated based on the result measured by the sliding surface shape measuring method of the piston ring of this invention mentioned above.

  Moreover, the piston ring of such a shape can aim at suppression of blow-by gas and reduction of oil consumption by making an outer peripheral sliding surface into the shape mentioned above. That is, as shown in FIG. 2A, the first sliding surface 2a and the second sliding surface 2b described above are formed on the outer peripheral sliding surface 2, and the first sliding surface 2a and the second sliding surface are formed. By installing the barrel apex 3, which is a part to which 2 b is joined, within the range of 5/100 to 33/100 from the upper surface 4 side of the piston ring with respect to the width in the sliding direction of the outer peripheral sliding surface 2, When the explosion pressure generated during the explosion stroke of the engine shown in 2 (b) acts on the upper surface 4 and the inner peripheral surface 6 of the piston ring 1 as the vertical pressure x and the horizontal pressure y, the radially inner side of the piston ring 1 The area of the first sliding surface 2a, which is a region where the horizontal pressure α toward the surface acts, can be reduced, and thereby the horizontal pressure α can be reduced. Therefore, the pressure contact force γ to the cylinder wall 20 can be maintained high, and blow-by gas can be suppressed. Further, by setting the width of the first sliding surface 2a in the radial direction of the piston ring 1, that is, the maximum value of the gap between the first sliding surface 2a and the cylinder wall 20 within the above range, the diameter of the piston ring 1 is set. It becomes possible to inhibit the gas that generates the horizontal pressure α directed inward in the direction from entering the gap, and as a result, blow-by gas can be suppressed. In addition, oil consumption can be reduced.

  In such a piston ring, it is possible to suppress blow-by gas and reduce oil consumption by making the outer peripheral sliding surface shape as described above. In particular, the precision of the outer peripheral sliding surface shape is required. Is done. Therefore, the above effect can be sufficiently obtained by measuring the shape of the outer peripheral sliding surface according to the present invention and increasing its accuracy.

  Hereinafter, the shape of the barrel face piston ring having the shape optimally measured by the measuring method of the present invention will be described in detail for the barrel apex, the first sliding surface, and the second sliding surface.

  Such a piston ring has a first sliding surface whose outer circumferential sliding surface is inclined in a curved shape inward in the radial direction of the piston ring toward an upper surface which is a surface on the combustion chamber side of the piston ring, and the piston ring A second sliding surface inclined in a curved shape radially inward of the piston ring toward a lower surface, which is a surface on the crank chamber side, and the first sliding surface and the second sliding surface are joined to each other. The position of the barrel apex as a part is preferably used within a range of 5/100 to 33/100 from the upper surface side of the piston ring with respect to the width in the sliding direction of the outer peripheral sliding surface.

  In the present invention, it is possible to accurately measure the shape of the outer peripheral sliding surface even when the barrel apex is located in the above range, so that the barrel apex is set to a desired position with high accuracy. Can do. Furthermore, by setting the position of the barrel apex within the above range, the area of the first sliding surface formed on the upper surface side of the piston ring can be made smaller than the barrel apex. The region where the pressure acts as a force toward the radially inner side of the piston ring is narrowed. Therefore, inevitably, the force to cancel the pressure contact force against the cylinder wall is weakened, and the sealing performance can be improved.

  Further, in the present invention, the barrel apex is preferably formed in a curved surface shape. If the barrel apex is formed in a curved surface shape, excessive pressure can be prevented from concentrating when it is pressed against the cylinder wall, and sliding friction can be reduced. Furthermore, it has an effect in improving followability.

  Moreover, it is preferable that the width | variety of the sliding direction in the outer peripheral sliding surface 2 of the piston ring of this invention is used within the range of 0.3-4.0 mm.

  Further, the shape of the first sliding surface is not particularly limited as long as it is a shape inclined inward in the radial direction toward the upper surface of the piston ring, and the inclined surface is curved and convex. .

  As the degree of inclination inward in the radial direction, the width in the piston ring radial direction of the first sliding surface, that is, the distance in the piston ring radial direction between the barrel apex and the upper end of the first sliding surface, It is preferably used within a range of 1 to 20 μm.

  Furthermore, it is preferable that the width in the piston ring axial direction of the first sliding surface is used within a range of 0.001 to 1.35 mm. With the piston ring sliding surface shape measuring method of the present invention, it is possible to accurately measure the sliding surface shape. Therefore, it is accurate whether or not the degree of inclination of the first sliding surface is within the above range. Highly measurable.

  The width of the first sliding surface in the piston ring radial direction is the distance in the piston ring radial direction between the portion located on the uppermost side (most combustion chamber side) of the first sliding surface and the barrel apex. Means. Specifically, as shown in FIG. 4, a straight line A passing through a portion p located on the uppermost side in the sliding direction of the first sliding surface 2a and drawn parallel to the piston ring axial direction, and the barrel apex 3 means a distance C from a straight line B that passes through 3 and is drawn parallel to the piston ring axis direction.

  In addition, the width in the piston ring axial direction of the first sliding surface referred to here is the piston between the portion of the first sliding surface located on the uppermost side (most combustion chamber side) of the piston ring and the barrel apex. It means the distance in the ring axis direction. Specifically, as shown in FIG. 4, a straight line D drawn through the portion p located on the uppermost side of the sliding direction of the first sliding surface 2a and parallel to the piston ring radial direction, and the barrel apex 3 means a distance F from a straight line E that passes through the line 3 and is drawn parallel to the piston ring radial direction.

  In the present invention, by setting the width of the first sliding surface in the piston ring axial direction within the above-described range, when the explosion pressure acts on the upper surface of the piston as a vertical pressure during the explosion stroke, the explosion pressure is Since the area of the region acting as a force inward in the ring radial direction can be reduced, the force for canceling the pressure contact force of the piston ring against the cylinder wall can be reduced. Therefore, it has an effect on improvement of sealing performance and suppression of blow-by gas. In addition, by setting the width of the first sliding surface in the radial direction of the piston ring in the above-described range, gas can be prevented from entering the gap between the first sliding surface and the cylinder wall during the explosion stroke. As a result, it is possible to reduce the force that cancels the pressure contact force of the piston ring against the cylinder wall. Therefore, it similarly has an effect of improving the sealing performance and suppressing blow-by gas. As described above, in the piston ring according to the present invention, the above effect can be obtained by setting the shape of the first sliding surface to the above-described range. By measuring the outer peripheral sliding surface, it can be accurately measured whether it is in the above range, and the shape of the sliding surface can be adjusted with high accuracy.

  Next, the 2nd sliding surface in the piston ring of this invention is demonstrated. The shape of the second sliding surface is not particularly limited as long as it is a shape inclined inward in the radial direction toward the lower surface of the piston ring, and the inclined surface is curved and convex.

  In such a second sliding surface, the radial width of the piston ring is preferably used within a range of 0.001 mm to 0.1 mm. Further, the width of the second sliding surface in the piston ring axial direction is preferably used within a range of 0.3 to 3.6 mm. Since the method for measuring the sliding surface shape of the piston ring according to the present invention can accurately measure the sliding surface shape, it is accurate whether the degree of inclination of the second sliding surface is within the above range. Highly measurable.

  The width of the second sliding surface in the piston ring radial direction is the piston ring diameter between the portion of the second sliding surface located on the lowest side in the sliding direction of the piston ring and the apex of the barrel. It means the distance in the direction. Specifically, as shown in FIG. 4, a straight line G passing through a portion q located on the lowermost side of the sliding direction of the second sliding surface 2 b and drawn parallel to the piston ring axial direction, and the barrel It means an interval H with a straight line B passing through the apex 3 and drawn in parallel to the piston ring axis direction.

  Further, the width of the second sliding surface in the piston ring axial direction is the piston ring formed by the portion of the second sliding surface that is located on the lowest side in the sliding direction of the piston ring and the top of the barrel. It means the distance in the axial direction. Specifically, as shown in FIG. 4, a straight line I passing through the portion q located on the outermost side in the sliding direction of the second sliding surface 2 b and drawn parallel to the piston ring radial direction, and the apex of the barrel 3 means a gap J with a straight line E that passes through 3 and is drawn parallel to the piston ring radial direction.

  In addition, since the second sliding surface is curved, the curved surface is always in contact with the cylinder wall, so that the followability to the cylinder wall is excellent and the sliding friction is reduced.

  Furthermore, the torsion angle 40 of the piston ring as shown in FIG. 2A is preferably used within a range of 0 ° 10 ′ to 10 °. Since the piston ring having a twist angle in the above range can be measured in a stable state by measuring the outer peripheral sliding surface shape with the lower surface of the piston ring in close contact with the flat surface according to the present invention, The shape of the outer peripheral sliding surface can be measured accurately.

  The torsion angle refers to the torsion angle when the piston ring groove is not restrained by the upper surface or the lower surface of the piston ring groove, and is defined based on the numerical value obtained by the following equation.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

It is explanatory drawing explaining the sliding face shape measuring method of the piston ring of this invention. It is explanatory drawing which showed the effect | action of the piston ring which is the measuring object in the sliding surface shape measuring method of the piston ring of this invention. It is the schematic sectional drawing which showed the example of the piston ring which has an inner side defect | deletion part in this invention. It is explanatory drawing explaining the shape in the outer peripheral sliding surface of the piston ring in this invention. It is the schematic sectional drawing which showed an example of the piston ring which produces a twist at the time of the conventional use. It is the schematic sectional drawing which showed an example of the barrel face type piston ring which produces a twist at the time of the conventional use.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Piston ring 2 ... Outer periphery sliding surface 2a ... 1st sliding surface 2b ... 2nd sliding surface 3 ... Barrel vertex 4 ... Piston ring upper surface 5 ... Piston ring lower surface 6 ... Inner peripheral surface 7 ... Inner defect | deletion part 8 ... Chamfer 20 ... Cylinder wall 30 ... Piston 31 ... Piston ring groove 33 ... Piston ring groove lower surface 40 ... Twist angle

Claims (3)

It consists of an outer peripheral sliding surface, an upper and lower surface, and an inner peripheral surface, and has a substantially circular shape when the abutment is closed, and has an inner defect part where the upper inner end of the piston ring is cut off, and the twisting action by the inner defect part From the sliding surface shape measuring method for measuring the shape of the outer peripheral sliding surface that is a portion that slides with the cylinder wall of the piston ring that is fitted in the piston ring groove in a state of being inclined with respect to the cylinder wall. There,
The piston ring is arranged so that a lower surface, which is a surface on the crank chamber side of the piston ring, is in close contact with a flat surface, and the shape of the outer peripheral sliding surface of the piston ring is measured in a state where the piston ring is in close contact. Ring sliding surface shape measurement method.   The method for measuring a sliding surface shape of a piston ring according to claim 1, wherein the method for measuring the shape of the outer peripheral sliding surface of the piston ring is a stylus type. The piston ring has a first sliding surface whose outer peripheral sliding surface is inclined in a curved shape radially inward of the piston ring toward an upper surface which is a surface on the combustion chamber side of the piston ring, and a crank chamber of the piston ring A second sliding surface inclined in a curved shape radially inward of the piston ring toward the lower surface, which is a side surface,
The barrel apex where the first sliding surface and the second sliding surface are joined ranges from 5/100 to 33/100 from the upper surface side of the piston ring with respect to the width in the sliding direction of the outer peripheral sliding surface. Provided in the
The method for measuring a sliding surface shape of a piston ring according to claim 1 or 2, wherein a width of the first sliding surface in a radial direction of the piston ring is in a range of 1 to 20 µm.

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