JP2006136980A - Device and method for polishing crankshaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for polishing a crankshaft uniformly polishing pin parts without being affected by inertial force and realizing further improvement of surface roughness. <P>SOLUTION: In this device, each of the pin parts 4 is clamped under prescribed load by clamping means 7A, 7B, 7C and 7D constituted of a pair of arms 5 and 6, the crankshaft 1 is rotated with a journal part 3 as a center, and the surfaces of the pin part 4 are polished by frictional force by sliding contact of polishing members 8 provided on each of the arms 5 and 6 and the pin parts 4. The clamping means 7A and 7B and the clamping means 7C and 7D for clamping each of the pin parts 4 having different phases by 180° are mutually connected by a connecting means 18 so that the inertial force F1 acting on the clamping means 7A and 7D for clamping the one pin part 4 when the pin part 4 rises, may be canceled by the self weight F2 of the clamping means 7B and 7C when the other pin part 4 lowers. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a crankshaft polishing apparatus and a crankshaft polishing method, and more particularly to a crankshaft polishing apparatus and a crankshaft polishing method for polishing a pin portion and a journal portion.

  For example, the pin part and journal part of the crankshaft, which is one of the engine parts of automobiles, function as sliding parts, so increasing the surface roughness reduces friction (frictional force) and improves fuel efficiency. It is known to be connected.

As a polishing apparatus for increasing the surface roughness of the pin part and the journal part, a feed mechanism for sequentially guiding the wrap film is provided on a shoe having a concave gripping part provided on the opposing surfaces of a pair of clamp arms, A polishing apparatus has been proposed in which a crankshaft is clamped together with a wrap film by a gripping portion, and the crankshaft and the wrap film are relatively rotated to polish a shaft portion (see, for example, Patent Document 1).
JP-A-9-136257 (pages 3 and 4; FIGS. 1 to 3)

  By the way, in the polishing apparatus, since the crankshaft is rotated around the journal portion as the rotation center, the clamp arm that clamps the journal portion does not rotate with the crankshaft when polishing the journal portion, but when the pin portion is processed, The clamp arm that clamps the pin portion rotates while drawing a radius that is half of the cylinder stroke, and thus vibrates vigorously during processing.

The pin part has a mass and tries to move at a constant speed and direction according to the law of inertia. However, since the pin part has a circular motion, the mass of the clamp arm is m, the half stroke is r, and the rotating part is rotating. If the angular velocity is ω, the inertial force F (F = mrω ² ) applied to the clamp arm changes the clamping force that clamps the pin portion.

  Originally, it is ideal to process the pin part under a constant load (constant clamp pressure), but because the pin part moves with the crankshaft, the upper part of the pin part and the upper arm are higher than the set value when the clamp arm is raised. Is pressed with a strong pressure, and conversely, the lower part of the pin part and the lower arm have a pressure smaller than the set value. In this way, since the inertia force affects the pin part in addition to the clamping pressure, this inertial force causes a change in the processing pressure (load fluctuation) at the processing site, resulting in variations in surface roughness and machining quality. It becomes unstable.

  Therefore, it is conceivable to eliminate the influence of the inertial force F as much as possible to reduce the processing pressure change and make the surface roughness constant. As one of them, it is effective to reduce the mass m of the clamp arm, but there is a limit to using a light material or adopting a lightweight structure. Since the half stroke r is determined by the specifications of a product (for example, an engine), this value cannot be changed. The angular velocity ω tends to increase in a processing line that is premised on recent high-speed processing, and cannot be reduced. Furthermore, in order to meet the demand for improvement in surface roughness, it is necessary to increase the contact frequency between more grindstones and the crankshaft, and low-speed machining cannot be realized.

  In addition, it is only necessary to be able to set a pressure that is strong enough to ignore the degree of influence of the pressure fluctuation, but a relatively light pressure is more suitable for improving the surface roughness. Therefore, the current polishing apparatus described in Patent Document 1 cannot cope with further improvement in surface roughness and high processing speed.

  Accordingly, the present invention provides a crankshaft polishing apparatus and a crankshaft polishing method capable of uniformly polishing a pin portion without being affected by inertial force, and realizing further improvement in surface roughness. With the goal.

  The present invention grips a pin part and a journal part under a predetermined load with a clamp means having a pair of arms attached so as to be swingable, and rotates a crankshaft around the journal part to each arm. This is a crankshaft polishing apparatus that polishes the surface of the pin portion and the journal portion by frictional force generated by sliding contact between the provided polishing member and the pin portion and the journal portion.

  In the present invention, the inertial force acting on the clamp means holding the pin portion when one pin portion ascends between the clamp means holding the pin portions whose phases are different by 180 degrees. It is connected by the connecting means so as to cancel out with the force when the pin part descends.

  According to the crankshaft polishing apparatus of the present invention, the inertial force acting on the clamping means holding the pin portion when one pin portion rises is canceled by the force when the other pin portion descends. Thus, the gripping force for gripping the pin portion can be kept constant. Therefore, even if the crankshaft is rotated at a high speed, the inertial force acting on the pin portion is canceled out, so that the pressure fluctuation is suppressed, and the pin portion can be polished with a constant gripping force (pressing force). The surface roughness of the surface can be further improved.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. This embodiment is an example in which the present invention is applied particularly to a polishing apparatus and a polishing method for smoothing a pin portion of a crankshaft constituting a part of an automobile engine.

[Configuration of polishing apparatus]
First, before explaining the configuration of the crankshaft polishing apparatus of the present embodiment, the crankshaft as a member to be polished will be briefly described.

  As shown in FIG. 1, the crankshaft 1 is formed with a journal portion 3 provided coaxially with the crankshaft 2 and a pin portion 4 provided at a position eccentric from the crankshaft 2. In the present embodiment, the crankshaft 1 used in a four-cylinder engine is illustrated, so that the pin portion 4 is provided at a position where the first and second pins and the third and fourth pins are shifted by 180 degrees. ing. In FIG. 1, the first pin, the second pin, the third pin, and the fourth pin are sequentially arranged from left to right.

  As shown in FIGS. 2 and 3, the polishing apparatus is configured to fix the journal portion 3 and the pin portion 4 with clamp means 7A, 7B, 7C, 7D having a pair of arms 5 and 6 that are swingably attached. Each of the journals is gripped under a load, and the crankshaft 1 is rotated about the journal portion 3, and the journal member is caused by frictional force generated by sliding contact between the polishing member 8 provided on each arm 5, 6, the pin portion 4, and the journal portion 3. This is an apparatus for polishing the surfaces of the portion 3 and the pin portion 4.

  2 and 3, only the clamping means 7A, 7B, 7C and 7D for clamping the pin portion 4 are shown, but the clamping means for polishing the journal portion 3 is not shown. Of course, the clamping means for polishing the journal part 3 has the same configuration as the clamping means 7A, 7B, 7C, 7D for clamping the pin part 4, and is provided at a position facing each journal part 3, respectively.

  The clamp means 7A to 7D are composed of a pair of arms 5 and 6 and a hydraulic cylinder 9 which is a pressure applying means for applying a gripping force by the arms 5 and 6 to the pin portion 4. The pair of arms 5 and 6 has a polishing member 8 that holds the pin portion 4 on one end side and polishes the surface of the pin portion 4. The polishing member 8 is made of a grindstone having a semicircular surface corresponding to the shape of the pin portion 7 as a polishing surface. The pair of arms 5 and 6 is configured such that one arm 5 is rotatable about the rotation shaft 10 with respect to the other arm 6 and one end side on which the polishing member 8 is provided can be opened and closed.

  In addition, a hydraulic cylinder 9 is attached to the pair of arms 5 and 6 to vary the gripping force (pressing force) for gripping the pin portion 4 on the other end side. One end 9 a of the hydraulic cylinder 9 is attached to the other end of the one arm 5, and the other end 9 b of the hydraulic cylinder 9 is attached to the other end of the other arm 6. When the hydraulic cylinder 9 is actuated and the cylinder rod 11 protrudes from the cylinder body 12 to the outside, the distal ends of the arms 5 and 6 provided with the polishing member 8 are biased in the closing direction, and the pin portion 4 is moved. The applied pressure increases. On the contrary, when the cylinder rod 11 moves in the direction in which the cylinder rod 11 is immersed in the cylinder body 12, the distal ends of the arms 5 and 6 provided with the polishing member 8 are opened, and the applied pressure for gripping the pin portion 4 is lowered. When the cylinder rod 11 is further moved in the direction of immersing in the cylinder body 12, the arms 5 and 6 are largely opened to release the grip of the pin portion 4.

  And the clamp means 7A-7D comprised in this way can be rock | fluctuated because one arm 5 is connected with the rocking | swiveling member 14 suspended from the top plate 13. FIG. The swing member 14 is rotatable about a support shaft 16 provided on a suspension plate 15 having one end fixed to the top plate 13 and supported at the other end on one arm 5. By making the shaft 17 pivotable, the clamp means 7A to 7D can swing. Actually, when the pin portion 4 of the crankshaft 1 moves circularly around the journal portion 3, the swing member 14 rotates with the pin portion 4 to move the clamp means 7 </ b> A to 7 </ b> D.

  In this embodiment, the clamp means 7A and the clamp means 7B holding the pin portions 4 of the first pin and the second pin, which are 180 degrees out of phase, and the pin portions 4 of the third pin and the fourth pin are held. The clamping means 7C and the clamping means 7D are connected together by the connecting means 18 respectively.

  As shown in FIGS. 2 and 3, the connecting means 18 includes a first connecting arm 19 attached to one clamping means 7A, a second connecting arm 20 attached to the other clamping means 7B, and the like. A third connection arm 21 for connecting the first connection arm 19 and the second connection arm 20, and a fourth connection arm 22 for fixing one end and holding the third connection arm 21 at the other end, These connecting arms 19, 20, 21, 22 are connected by a universal joint. Such connecting means 18 are all arranged in the direction of gravity.

  The first connecting arm 19 is substantially Y-shaped in plan view, and the Y-shaped portion is connected to a shaft portion 24 that is rotatable by a connecting portion 23 formed on the lower arm 6 of the clamping means 7A. Has been. The shaft portion 24 has spheres 25 at both ends, and the spheres 25 are connected as universal joints (free joints) so as to be rotatable in the XYZ directions with respect to the Y-shaped portion. Similarly, the second connecting arm 20 is also substantially Y-shaped in a plan view, and the Y-shaped portion of the second connecting arm 20 is rotatable with respect to a shaft portion 26 that is rotatable by a connecting portion 23 formed on the lower arm 6 of the clamping means 7B. Are connected. Similar to the shaft portion 24, the shaft portion 26 has spheres 27 at both ends, and the sphere 27 is connected to the Y-shaped portion as a universal joint so as to be rotatable in the XYZ directions.

  The third connecting arm 21 has spheres 28 at both ends and the center, and is universal so that the spheres 28 at both ends can rotate in the XYZ directions with respect to the lower ends of the first and second connecting arms 19 and 20. It is connected as a joint. In addition, a sphere 28 provided at the center of the third connecting arm 21 is connected to the other end of the fourth arm 22 as a universal joint so as to be rotatable in the XYZ directions.

  The fourth connecting arm 22 is provided orthogonal to the third connecting arm 21, and has one end fixed and the other end connected to a central sphere 28 formed on the third connecting arm 21.

  In this way, the first connecting arm 19, the second connecting arm 20, the third connecting arm 21 and the fourth connecting arm 22 are connected by the universal joint, and the phase is 180 degrees. By connecting the clamp means 7A for gripping different pin 1 and the clamp means 7B for gripping pin 2 and clamp means 7C for gripping pin 3 and clamp means 7D for gripping pin 4, respectively. The two clamp means 7A, 7B and the clamp means 7C, 7D are connected in a so-called seesaw shape.

"Crankshaft grinding method"
Next, a method for polishing the crankshaft 1 using the crankshaft polishing apparatus configured as described above will be described.

  First, the crankshaft 1 is chucked in a chucking portion of a crankshaft drive mechanism (not shown). The crankshaft 1 is chucked by gripping the crankshafts 2 at both ends with clamping means.

  Next, the hydraulic cylinders 9 of the respective clamping means 7A, 7B, 7C, 7D are operated to open the upper and lower arms 5, 6. The arm of the clamping means (not shown) that clamps the journal portion 3 is also opened in the same manner. After the arms 5 and 6 are opened, the clamp means 7A, 7B, 7C and 7D are brought close to the crankshaft 1 and then the hydraulic cylinder 9 is operated to close the arms 5 and 6, and the respective journal portions 3 and pins. The part 4 is clamped. Pressure is applied to the journal part 3 and the pin part 4 by a hydraulic cylinder 9 so that a desired gripping force is applied.

  Next, the crankshaft drive mechanism is operated to rotate the crankshaft 1. Then, the crankshaft 1 rotates around the crankshaft 2 that is coaxial with the journal portion 3. As a result, the clamping means for clamping the journal portion 3 is configured so that the journal portion 3 is not rotated with the rotation of the crankshaft 1 because the journal portion 3 is coaxial with the crankshaft 2 and the upper and lower arms Hold the posture as held by 5,6. The surface of the journal unit 3 is polished by the relative sliding contact between the rotation of the journal unit 3 and the polishing members 8 provided on the upper and lower arms 5 and 6 that hold the journal unit 3 with a predetermined pressure. Is done. As the surface roughness, for example, the surface roughness Ra is set to a mirror surface state of about 0.01 to 0.02.

  On the other hand, the clamping means 7A, 7B, 7C and 7D for clamping the pin portion 4 are located at positions where the pin portion 4 is eccentric with respect to the crankshaft 2, so that the swinging member 14 suspended from the top plate 13 is provided. To rotate the crankshaft 1. The surface of the pin portion 4 is polished by the rotation of the pin portion 4 and relative sliding contact with the polishing member 8 provided on the upper and lower arms 5 and 6 that hold the pin portion 4 with a predetermined pressure. .

  At this time, if the clamp means 7A and 7B for holding the first pin and the second pin and the clamp means 7C and 7D for holding the third pin and the fourth pin are not connected by the connecting means 18, respectively, the pin portion 4 is held. The applied pressure (clamping force) changes as shown in FIG. FIG. 4 shows a change in load received from the pin portion 4 when a load cell is provided on the polishing member 8 provided on the upper arm 5. The pressure setting value described in FIG. 4 is a setting value suitable for pressurizing the pin portion 4 so that the surface roughness is optimum.

  The pin portion 4 receives an inertial force because it rotates together with the crankshaft 1 while drawing an arc. Therefore, since an inertial force acts on the pin portion 4 in addition to the clamp pressure, the applied pressure for gripping the pin portion 4 varies as shown by the waveform shown in FIG. This variation in the applied pressure causes variations in the surface roughness of the pin portion 4 and makes the machining quality unstable.

  Therefore, as in the present embodiment, the clamp means 7A, the clamp means 7B, the clamp means 7C, and the clamp means 7D that clamp the 1st pin, the 2nd pin, the 3rd pin, and the 4th pin whose phases are different by 180 degrees are connected to each other. By connecting the means 18, the inertial force applied to the arms 5 and 6 is canceled out. FIG. 5 is a graph showing the reaction force that the connecting member 18 exerts on the clamping means 7A, 7B, 7C, and 7D. The reaction force that the connecting member 18 exerts on the clamping means 7A, 7B, 7C, and 7D has a waveform whose phase is shifted by 180 degrees with respect to the waveform of FIG. For example, when the clamping means 7A, 7B, 7C, and 7D rotate from the bottom part to the top part, the applied pressure is higher than the set value in FIG. 4, but the applied pressure is lower than the set value in FIG. ing. Therefore, in the present embodiment, the inertial force applied to the clamp means 7A, 7B, 7C, 7D is canceled by the reaction force of the connecting means 18.

  That is, for example, as shown in FIGS. 2 and 3, when the first pin is raised to the top part and the second pin is going to be lowered to the bottom part, the clamping means 7A and 7B are not connected by the connecting member 18 Since the arms 5 and 6 of the clamping means 7A that clamps the first pin try to remain with respect to the crankshaft 1, the inertia force F1 of the arms 5 and 6 acts downward. The inertial force F1 acting on the arms 5 and 6 is canceled by the own weight F2 (force to lower down) of the clamping means 7B that holds the second pin. The own weight F2 of the clamping means 7B that holds the second pin is transmitted from the second connecting arm 20 connected by the universal joint to the third connecting arm 21 and the first connecting arm 19, and holds the first pin. Is transmitted to the clamping means 7A. Then, the inertia force F1 is canceled out by its own weight F2 by the clamp means 7B.

  FIG. 6 is a pressure change diagram of the pin portion 4 when the connecting means 18 is connected to the clamp means 7A, 7B, 7C, 7D. As can be seen from this figure, the clamp means 7A, the clamp means 7B, the clamp means 7C, and the clamp means 7D, which are 180 degrees out of phase, are connected by the connection means 18 so that a substantially constant pressure is applied to the pin portion 4. Can be made. Therefore, the pin portion 4 can be uniformly polished without unevenness.

"Effect"
As described above, according to the present embodiment, the clamp means 7A, the clamp means 7B, the clamp means 7C, and the clamp means 7D that hold the pin portions 4 that are 180 degrees out of phase are connected by the connection means 18 having a seesaw structure, The inertial force F1 acting on the clamp means 7A, 7D holding the pin part 4 when one pin part 4 is raised, and the force F2 (clamp means 7B, 7C when the other pin part 4 is lowered) Therefore, the gripping force for gripping the pin portion 4 can always be kept constant. Therefore, even if the crankshaft 1 is rotated at a high speed, the inertial force F1 acting on the pin portion 2 is canceled, so that the pressure fluctuation is suppressed, and the pin portion 4 can be polished with a constant gripping force (pressing force). It is possible to further improve the surface roughness of the pin portion surface.

  In addition, according to the present embodiment, the first connecting arm 19, the second connecting arm 20, the third connecting arm 21 and the fourth connecting arm 22 are connected by a universal joint, so-called seesaw structure connecting means. 18 so that the own weight F2 of the clamping means 7A, 7B, 7C, 7D for clamping the other pin portion 4 is efficiently applied to the inertial force F1 acting on the one pin portion 4, thereby canceling out the inertial force F1. Can do.

  Moreover, according to this Embodiment, since the connection means 18 is arrange | positioned toward the gravitational direction, the own weight F2 of clamp means 7A, 7B, 7C, 7D can be made to act on one pin part 4 without waste. it can.

  Further, according to the present embodiment, when one pin portion 4 is raised, the inertia force F1 acting on the clamping means 7A, 7B, 7C, 7D holding the pin portion 4 is applied to the other pin portion 4. Since the polishing is carried out while canceling with the force (the weight of the clamping means 7A, 7B, 7C, 7D) when moving down, the pin portion 4 can be uniformly polished without being affected by the inertial force. Therefore, the crankshaft 1 can be polished by rotating at a high speed, and the surface roughness can be made more specular.

[Other embodiments]
Although specific embodiments to which the present invention is applied have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made.

  In the above-described embodiment, the polishing member 8 is provided at the tip of the arms 5 and 6, and the polishing member 8 itself is a grindstone. However, the wrap film coated with the abrasive is placed along the shoe, The journal part 3 and the pin part 4 may be polished.

  In the above-described embodiment, the crankshaft 1 for a four-cylinder engine has been described as an example. However, the present invention can also be applied when polishing a crankshaft for a six-cylinder engine.

It is a front view of the crankshaft grind | polished with the grinding | polishing apparatus of the crankshaft of this Embodiment. It is a perspective view which shows a part of grinding | polishing apparatus of the crankshaft of this Embodiment. It is sectional drawing of the grinding | polishing apparatus of the crankshaft of this Embodiment. It is a graph which shows the load change received from a pin part when providing a load cell on the grinding | polishing member provided in the upper arm. It is a graph which shows the reaction force which a connection member exerts on a clamp means. It is a pressurizing force change figure of a pin part when a connection means is connected with a clamp means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Crankshaft 2 ... Crankshaft 3 ... Journal part 4 ... Pin part 5, 6 ... Arm 7A, 7B, 7C, 7D ... Clamp means 8 ... Polishing member 9 ... Hydraulic cylinder 18 ... Connection means 19 ... 1st connection arm 20 ... 2nd connection arm 21 ... 3rd connection arm 22 ... 4th connection arm

Claims (4)

A polishing member provided on each arm by holding the pin part and the journal part under a predetermined load with a clamp means having a pair of arms attached so as to be swingable, and rotating the crankshaft around the journal part. A crankshaft polishing apparatus for polishing the surface of the pin part and the journal part by frictional force generated by sliding contact between the pin part and the journal part,
When the other pin part lowers the inertial force acting on the clamp means holding the pin part when one pin part ascends between the clamp means holding the pin parts 180 degrees out of phase. The crankshaft polishing apparatus is characterized in that it is connected by a connecting means so as to cancel out with the force of. The crankshaft polishing apparatus according to claim 1,
The connecting means connects a first connecting arm attached to one clamping means, a second connecting arm attached to the other clamping means, and connects the first connecting arm and the second connecting arm. A crankshaft comprising a third connecting arm and a fourth connecting arm that fixes one end and holds the third connecting arm at the other end, and is connected to each other by a universal joint. Polishing equipment. The crankshaft polishing apparatus according to claim 1 or 2,
The crankshaft polishing apparatus, wherein the connecting means is arranged in the direction of gravity. A polishing member provided on each arm by holding the pin part and the journal part under a predetermined load with a clamp means having a pair of arms attached so as to be swingable, and rotating the crankshaft around the journal part. A crankshaft polishing method for polishing the surface of the pin part and the journal part with a frictional force caused by sliding contact between the pin part and the journal part,
Among the clamping means for clamping the pin part that rotates with the rotation of the crankshaft, when the arms that respectively hold the pin parts that are 180 degrees out of phase are connected by the connecting means, and one of the pin parts rises A method for polishing a crankshaft, characterized by canceling and polishing an inertial force acting on a clamp means holding the pin portion by a force when the other pin portion is lowered.

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