JPH02668Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a piston ring tension measuring device in an internal combustion engine or the like.

Generally, in an internal combustion engine, a piston ring, which is made by notching one end of an annular body and providing an abutment gap of an appropriate size, is inserted into an annular ring groove along the circumferential surface of a piston that fits into a cylinder. This prevents the pressure gas in the combustion chamber from leaking into the crank chamber, and also adjusts the oil film on the cylinder wall. Therefore, if the tension in the circumferential tangential direction at the abutment of the piston ring is too large, the oil film will break, and if it is too small, pressure gas leakage or oil will rise into the combustion chamber, which will cause problems in either case. Since only piston rings whose tension is within the specified value are used, it is necessary to measure the piston ring tension.

For example, as shown in FIG. 1, this conventional tension measuring device places a piston ring 2 on the horizontal upper surface of a surface plate 1 so that its cylindrical axis is perpendicular.
A steel band or wire 3 whose one end is fixed to the upper surface of the surface plate 1 and is arranged approximately parallel to the upper surface of the surface plate 1 is wound once around the outer peripheral surface of the piston ring 2,
The other end of this wire 3 is connected via a spring balance 5 to a lever 4 rotatably mounted on the upper surface of the surface plate 1 approximately parallel thereto, and the size is the same as a predetermined abutment gap that serves as a reference. Insert the feeler gauge 6 of C between the gap of the piston ring 2 which is the object to be measured,
Use the lever 4 to tighten the abutment gap while narrowing it, and when the specified abutment gap size is reached,
There is a method that measures tension by removing the feeler gauge 6 and reading the load on the spring balance 5 at this time.

However, in this device, since the steel wire and the like are in contact with the piston ring over the entire length of its outer circumference, the static frictional resistance caused by the contact is also added to the measured value. Therefore, this static frictional force causes an error in the measurement results, so in order to convert this frictional force into a dynamic frictional force so that it can be ignored as a resistance force, hit the piston ring 2, surface plate 1, etc. with a mallet to remove the piston. Vibration is applied between the ring and the wire, but this method is extremely inefficient in measurement, and it also causes measurement errors due to the vibration being applied to the spring and the variation in the way the vibration is applied. There are some drawbacks that can easily occur.

Therefore, in the present invention, a pair of frames are pivotally attached at one end to the left and right sides of the piston ring to be measured so that they can rotate freely, and the outer peripheral surface of the piston ring is reduced in diameter by the two frames. A clamping means which is designed to be clamped as shown in FIG. Contact parts such as pins or balls with a small radius of curvature that come into contact with the outer peripheral surface of the piston ring when the piston ring is tightened by both frames are provided at appropriate intervals along the circumferential direction of the piston ring. This is intended to reduce the contact frictional resistance between the object to be measured and the measuring device to a negligible extent, thereby improving measurement accuracy as well as measurement efficiency.

Next, the present invention will be explained based on an embodiment. In FIG. 2, 10 indicates a base such as a surface plate, 11, 1
Reference numeral 1' denotes a semicircular frame in a plan view for clamping the outer circumferential surface of the piston ring 12, which is the object to be measured, from the outside by abutting portions 13, which will be described later.

Both frames 11 and 11' are arranged so that their inner circumferential surfaces 14 and 14' face each other, and the center axis of the arc is substantially perpendicular to the surface of the base 10. Then, the one frame 11 is fixed to the surface of the base 10 with bolts 15 or the like, and the other frame 11' has its base end attached to the fixed frame 11.
It is rotatably attached to one end of the support shaft 16 having an axis parallel to the center axis of the circular arc.

Both frames 11 and 11' have a convex curved surface such as a pin or ball with a small radius of curvature that comes into contact with the outer circumferential surface of the piston ring 12 disposed between them when they approach each other. The abutting portions 13 having a shape of 13 are disposed along a circumference corresponding to the outer diameter D of the piston ring 12 at appropriate intervals.

As a specific example of this abutting portion 13, a circular hole 17 having an axis parallel to the central axis of the inner circumferential surface portions 14, 14' of each frame body is formed from the end face of both the frame bodies 11, 11'. They are bored at appropriate pitches along the circumference, and then U-shaped grooves 18 are bored in the inner peripheral surface portions 14, 14' so as to partially overlap with the respective round holes 17, and cylindrical grooves 18 are formed in each of the round holes 17. The contact portion 13 is constructed by inserting a shaped or cylindrical pin shaft.

Further, a flange portion 19 extending in the radial direction of the arc is formed at the free end of the rotating frame 11' opposite to the position of the support shaft 16, while the upper surface of the base 10 is A tightening means 21 having a spindle 20 that moves parallel to this and a length measuring means 21' such as a micrometer is fixed, and the tip of the spindle 20 of the tightening means 21 is attached to the rotating frame 11'. The piston ring 12 is brought into contact with a tightening force detector 22 such as a load cell provided on one side of the flange portion 19 of the flange portion 19, and presses the rotating frame 11' in the direction of the fixed frame 11 through this. Connect so that it can be tightened.

Then, the detector 22 is connected to the dynamic strain meter 23 by a wire 24.
Then, this dynamic strain meter 23 is connected to a display device 26 such as a digital meter through a wire 25.

To measure the tension of the piston ring 12 with this configuration, in the apparatus shown in FIG.
After moving the spindle 20 away from the detector 22 on the flange portion 19 of the rotating frame 11', a master ring having an annular shape or the like which has been finished in advance to have the same outer diameter as the bore diameter of the engine is attached to both the frames 11. ，
11' into the groove 18, and operate the tightening means 21 again to bring the tip of the spindle 20 into contact with the detector 22 while rotating the free end of the rotating frame 11' in the direction of the fixed frame 11. After applying a tightening load to the detector 22, the tightening means 21 is loosened until the scale on the display device 26 becomes zero, and the scale on the length measuring means 21' at this time is recorded.

This eliminates the tightening load required for the elastic deformation of the entire system of the measuring device due to the applied tightening force, and serves as a reference for the tightening load described later. contacts the pin-shaped contact portions 13 provided on both frames 11, 11', and the circle of the envelope formed by the 13 rows of contact portions corresponds to the circular dimension of the reference bore diameter. The scale can be used as the position where the free end of the rotating frame 11' is closest to the fixed frame 11 when . That is, it becomes a reference scale when adjusting the abutment gap of the piston ring 12 to be measured later to a specified dimension C. Next, the spindle 20 of the tightening means 21 is moved away from the free end of the rotating frame 11' again, the master ring and the piston ring 12 are exchanged, and the scale on the tightening means 21 is again adjusted to the master ring in the same manner as before. Press the free end of the rotating frame 11' towards the fixed frame 11 until the scale is the same as shown. As a result, the abutment gap dimension of the piston ring 12 is set to the specified dimension C.
is the same, and if the scale on the display device 26 at this time is read, it indicates the force corresponding to the tension.

Note that when this force is W ₁ , the tension W ₀ in the tangential direction of the circumference on the outer circumference of the piston ring is calculated by the distance l ₁ from the rotating frame 11' base end support shaft 16 to the center of the piston ring and the base end support shaft. 16 to the point of load application to the detector 22, _l2 .

When a force W ₁ is applied to the load application point, a radial stress of magnitude Pa acts as a uniformly distributed load on the semicircular portion pressing the piston ring inside the rotating frame 11'. At this time, the diameter of the piston ring is ra, the circumferential stress acting perpendicular to the piston ring cross section is σt, the width of the piston ring is b, and the thickness is △
1, the balance of forces in the semicircular part is given by the basic formula for thin-walled cylinders in mechanics of materials: 2∫〓 ^/2 ₀ Para△lsinθdθ≒2σt△lb The tension W ₀ mentioned above is the force in the circumferential direction. Since σt△lb=W ₀ , 2∫〓 ^/2 ₀ Para△lsinθdθ≒2W ₀ .

Since the force acting on the rotating frame 11' expressed by the above equation is a uniformly distributed load, it can be considered as a concentrated load of magnitude 2W ₀ acting on the center of the piston.

Therefore, considering the balance of moments around the base end support shaft 16 of the rotating frame 11', 2W ₀ l ₁ = W ₁ l ₂ , and the distance from the base end support shaft 16 to the center of the piston ring l ₁ When is exactly half of the distance l ₂ from the base end support shaft 16 to the load application point of the detector 22, W ₁ is the tension
Matches W ₀ .

In this measurement, unlike the conventional example described above, a feeler gauge is not inserted into the abutment gap of the piston ring 12, so the tightening force by the tightening means 21 is applied when the abutment dimension of the piston ring is free (no load). It can be read as the net tension due to the change in the abutment dimension from the state) until the specified abutment dimension is reached.

Furthermore, during the measurement, the outer circumferential surface of the piston ring 12 only makes line contact with the pin-shaped contact portion 13 in the groove 18 of both frames 11, 11', and the contact point is on the outer circumference of the piston ring 12. Rather than the entire circumference along the circumference, they are scattered at interrupted points along the circumferential direction, making it possible to extremely reduce the frictional resistance force caused by the contact between the piston ring and the measuring instrument compared to the conventional case. The accuracy of tension measurements can be improved.

5 and 6 show another embodiment in which a relay abutment piece 27 is removably inserted between the detector 22 and the spindle 20 of the tightening means 21 in the above embodiment, and the This is intended to streamline the work of replacing items, and a rod-shaped contact piece 27 is inserted between the pressure-sensitive surface of the detector 22 and the tip of the spindle 20 of the tightening means 21. is supported by a bracket 28 so as to be slidable in parallel with the direction of expansion and contraction of the spindle 20, and this bracket 28 is attached to the base 10 so as to be vertically movable.

According to this configuration, when measuring tension, the tightening means 2
1 spindle 20 is pressed against the detector 22 via the contact piece 27, and the piston ring 12
When installing the frame bodies 11 and 11' into the frames 11 and 11', simply loosen the spindle 20 of the tightening means 21 a little, and the contact piece 27 can be flipped up and rotated as shown by the two-dot chain line in FIG. The restraint of the free end of the frame 11' can be released, and a gap corresponding to the length of the abutting piece 27 is created between the tip of the spindle 20 of the tightening means 21 and the free end of the rotating frame 11'. Since the movable frame 11' can be rotated that much (see the two-dot chain line in FIG. 5), the piston ring 12 can be inserted and removed between the two frames 11 and 11' very easily.

In both of the above embodiments, a cylindrical pin serving as the contact portion 13 to the outer periphery of the piston ring may be attached to each frame so as to be rotatable around the axis, and the contact with the outer periphery of the piston ring may be a point contact. Alternatively, the ball may be rotatably supported at both ends. With these configurations, the contact friction on the outer periphery of the piston ring becomes dynamic friction, and the frictional resistance can be further reduced.

In addition, a cylindrical pin-shaped abutting part similar to that described above is provided protrudingly on one side of both the disk-like frames 11, 11', and the outer circumferential surface of the piston ring is supported and held by this abutting part row. Alternatively, a U-shaped groove or the like into which the outer diameter portion of the piston ring can fit may be formed on the circumferential surface of these pins.

Note that both the frames 11 and 11' are connected to the base 10.
It is rotatably mounted on both frames 11, 11'.
The tightening means 21 may be configured in a vise shape so as to pinch both flanges at the free end from the outside. Two levers may be provided facing each other, and the tightening means 21 may be brought into contact with the levers from the outside.

In summary, in the present invention, a pair of left and right frames are rotatably pivoted at one end on both the left and right sides of a piston ring to be measured, and one of the frames has the piston attached between the two frames. It is related to a tightening means that pinches the ring in the direction of the reduced diameter, and a detection device for detecting the tightening force is installed at the related location, so as mentioned above, the If the master ring is used as the reference outer diameter, the tension can be measured simply by adjusting the tightening dimension using the tightening means to match the reference diameter. Also,
If a reference tension and a reference abutment gap size are set in advance using a reference piston ring and a feeler gauge, it is also possible to easily measure the deviation of the tension of the piston ring to be measured from the reference tension. Since the contact portions provided on both frames are pin-shaped or ball-shaped with an extremely small radius of curvature compared to the radius of curvature of the piston ring, the contact with the outer circumferential surface of the piston ring is a line contact or a point contact. Since the abutting portions are arranged so as to make contact only at multiple locations appropriately spaced along the circumferential direction of the outer periphery of the piston ring, the contact resistance between the object to be measured and the measuring instrument can be extremely reduced. . This eliminates the need to apply vibration to remove frictional resistance as in the past, improving measurement efficiency, and since no vibration is applied, there is no wear on the contact parts, resulting in a longer lifespan of the device.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a conventional device, FIG. 2 is a plan view showing an embodiment of the present invention, FIG. 3 is a partially cutaway sectional view taken along the line -- in FIG. FIG. 5 is a plan view showing another embodiment of the present invention, and FIG. 6 is a side view taken along the line - in FIG. 5. 10... Base, 11, 11'... Frame, 12... Piston ring, 13... Contact portion, 15... Bolt, 16
...Spindle, 19...Flange part, 20...Spindle,
21... Tightening means, 21'... Length measuring means, 22... Detection device, 27... Contact piece.

Claims (1)

[Scope of utility model registration request] A pair of left and right frames are rotatably attached at one end to the left and right sides of the piston ring to be measured, and one of the frames is provided with a diameter-reduced frame for the piston ring between the two frames. A detection device for detecting the tightening force is provided at the relevant location, and a detection device for detecting the tightening force is provided on both frames, and a detection device is provided on both frames to detect the force of the piston ring when the two frames tighten the piston ring. A piston ring tension measuring device comprising a plurality of pins or balls with a small radius of curvature that are in contact with the outer peripheral surface of the ring and are provided at appropriate intervals in the circumferential direction of the piston ring.