JP4655818B2 - Lubricant evaluation method - Google Patents

Description

  The present invention relates to a lubricant evaluation method for evaluating the lubrication performance of a lubricant by plastically deforming a columnar metal test piece in which a lubricant for facilitating plastic working is applied to an outer peripheral surface. It is.

In general, in order to facilitate plastic processing such as drawing, drawing, and rolling of wire rods, lubricants such as solid lubricants such as zinc phosphate and molybdenum disulfide, and liquid lubricants such as mineral oil, fats and oils, and surfactants Is applied to the surface of a metal material. As a lubricant evaluation method for evaluating the lubrication performance of the lubricant for facilitating such plastic working, a ring compression test method, a ball threading test method, a spike test method, a taper cup test method, and the like have been proposed. For example, the spike test method is shown in Patent Document 1, and the taper cup test method is shown in Patent Document 2.
Japanese Patent No. 3227721 JP 2004-12296 A

  The spike test method disclosed in Patent Document 1 is a funnel shape in which an upper funnel portion that is slightly inclined with respect to a horizontal plane and a lower funnel portion that is greatly inclined with respect to a horizontal plane are continuously connected via R (R). A cylindrical metal test piece is placed on a die having an inner peripheral surface, and the metal test piece is pushed into the die under application of a lubricant to form a spike, and then the formed metal piece is ejected from the opposite direction. And the performance of the lubricant applied to the end face of the metal test piece is evaluated based on the load required to achieve a certain push-in amount and the load required to protrude.

  Further, the taper cup test method disclosed in Patent Document 2 has a smaller diameter from the rear end surface of the released metal test piece to the front end surface than the metal test piece whose front end surface and side surface are constrained by a mold. Backward extrusion is performed using a punch having a tapered surface, and the lubrication performance applied to the end face of the metal test piece is evaluated based on the forming load or stripper load at that time.

  By the way, in the conventional lubricant evaluation method described above, plastic deformation is applied to the end face of the metal test piece to evaluate the lubrication performance of the lubricant applied to the end face. It was difficult to evaluate the lubrication performance of the lubricant when worn. For this reason, the lubrication performance of the lubricant used for the outer peripheral surface of the wire in drawing, drawing, rolling and the like of the wire cannot be accurately evaluated.

  The present invention has been made against the background of the above circumstances, and the object of the present invention is to provide a lubricant that can accurately evaluate the lubrication performance of a lubricant applied to the side surface of a metal material during plastic working. To provide an evaluation method.

The gist of the invention according to claim 1 for achieving the above object is to evaluate the lubricating performance of the lubricant by plastically deforming a columnar metal test piece in which the lubricant is adhered to the outer peripheral surface. a lubricant evaluation method to perform plastic working to project the metal specimen nipped at a fixed stroke from the both end faces with the flange-like intermediate portion of the metal test piece to the outer peripheral side, that at that time The lubricating performance of the lubricant is evaluated based on the surface enlargement ratio of the metal test piece and the pressing load on the metal test piece.

  The gist of the invention according to claim 2 is that the plastic working of the invention according to claim 1 includes a first mold having a pressing plane perpendicular to the pressing direction, and a shaft of the metal test piece. The metal test piece is clamped between a second mold having an inclined pressing surface inclined in a taper shape around the center.

Further, the gist of the invention according to claim 3 is that, in the invention according to claim 1, further, the metal test piece is inserted into the bottomed fitting hole from one end face of the metal test piece. Based on the protruding load when one end of the metal test piece is protruded from the bottom fitting hole by performing plastic working to clamp the metal test piece with a fixed stroke and project the intermediate part of the metal test piece in a flange shape toward the outer periphery. The lubricating performance of the lubricant is evaluated.

  The gist of the invention according to claim 4 is that the plastic working of the invention according to claim 3 is performed by pressing the fitting hole with the bottom into which one end of the metal test piece is fitted and the pressing direction perpendicular to the pressing direction. The metal test piece is clamped between a first mold having a flat surface and a second mold having an inclined pressing surface inclined in a taper shape about the axis of the metal test piece. It is characterized by being.

  Further, the gist of the invention according to claim 5 is that, in the claim 2 or 4, the inclined pressing surface is inclined with respect to a surface orthogonal to the pressing direction in an angle range of 5 to 70 degrees. It is characterized by being.

According to the lubricant evaluation method of the invention according to claim 1, plastic working is performed in which the metal test piece is clamped from both end faces with a constant stroke so that an intermediate portion of the metal test piece protrudes in a flange shape toward the outer peripheral side. Since the lubrication performance of the lubricant was evaluated based on the surface expansion ratio of the metal test piece and the pressing load on the metal test piece at that time, the metal test piece was attached to the side surface which is an intermediate part of the metal test piece Since the lubrication performance of the lubricant has a close influence on the surface expansion ratio of the metal test piece in the plastic working that protrudes in the form of a flange from its intermediate part to the outer peripheral side, it is attached to the side surface of the metal material during the plastic working The lubricating performance of the lubricant can be accurately evaluated.

  According to the lubricant evaluation method of the invention according to claim 2, the plastic working is tapered with the first mold having a pressing plane perpendicular to the pressing direction and the axis of the metal test piece as a center. A first metal mold and a second metal mold that become narrower as they move away from the metal test piece. The plastic deformation load reflecting the lubrication performance of the lubricant is reflected in the pressing load of the mold, and the metal material during the plastic working The lubricating performance of the lubricant applied to the side surface can be more accurately evaluated.

  According to the lubricant evaluation method of the invention of claim 3, the metal test piece is clamped with a constant stroke from both end faces in a state where one end of the metal test piece is fitted in the bottomed fitting hole. We perform plastic working to project the intermediate part of the metal test piece to the outer peripheral side in a flange shape, and based on the protruding load when projecting one end part of the metal test piece from the bottomed fitting hole, the lubricating performance of the lubricant From the evaluation, it can be seen that the metal from the bottom fitting hole has a strong interference fit between the outer peripheral surface of one end of the metal test piece and the inner peripheral surface of the bottom fitting hole into which the metal test piece is fitted. Since the lubrication performance of the lubricant closely affects the protruding load when one end of the test piece is projected, it is possible to accurately evaluate the lubrication performance of the lubricant applied to the side surface of the metal material during plastic processing. it can.

  Moreover, according to the lubricant evaluation method of the invention which concerns on Claim 4, the said plastic working has a fitting hole with a bottom which inserts the one end part of the said metal test piece, and a press plane orthogonal to a press direction. Since the metal test piece is clamped between the first mold and the second mold having an inclined pressing surface inclined in a taper shape with the axis of the metal test piece as a center, Since it protrudes in the form of a flange from the middle part of the metal test piece through the gap between the first mold and the second mold that becomes narrower as the distance from the metal test piece increases, the plasticity reflects the lubrication performance of the lubricant. The deformation load is reflected in the pressing load of the mold, and the lubricating performance of the lubricant applied to the side surface of the metal material during plastic working can be more accurately evaluated.

  Further, according to the lubricant evaluation method of the invention according to claim 5, the inclined pressing surface is inclined with respect to the surface orthogonal to the pressing direction in an angle range of 5 to 70 degrees. Since it protrudes in the form of a flange from the middle part of the metal test piece through the gap between the first mold and the second mold that becomes narrower as the distance from the metal test piece increases, the plasticity reflects the lubrication performance of the lubricant. The deformation load is appropriately reflected in the pressing load of the mold.

  Here, preferably, in the second mold, an annular flat surface orthogonal to the pressing direction is provided adjacent to the outer periphery of the tapered pressing surface. In this way, it is possible to avoid a sudden increase in load at the end of plastic deformation.

  Preferably, in the second mold, a bottomed fitting hole for fitting the other end portion of the metal test piece is provided adjacent to the inner periphery of the tapered pressing surface. If it does in this way, in plastic deformation, positioning to the 2nd metallic mold of the other end part of a metal test piece will be performed stably.

  Preferably, the gist of the apparatus invention in which the method for evaluating a lubricant according to the first aspect of the present invention is suitably implemented, that is, the gist of the apparatus for evaluating a lubricant is a columnar shape in which the lubricant is attached to the outer peripheral surface. A lubricant evaluation apparatus for evaluating the lubrication performance of the lubricant by plastically deforming the metal test piece of (a), wherein (a) a first mold having a pressing plane perpendicular to the pressing direction; and (b) A second mold having an inclined pressing surface inclined in a taper shape about the axis of the metal test piece; and (c) the metal test piece between the first mold and the second mold. A load sensor that detects a pressing force, that is, a pressing load when the surface is clamped with a certain stroke, and evaluates the lubricating performance of the lubricant based on the pressing load detected by the load sensor. To do.

  Preferably, the gist of the apparatus invention in which the method for evaluating a lubricant according to the third aspect of the present invention is suitably implemented, that is, the gist of the apparatus for evaluating a lubricant is a columnar shape in which the lubricant is attached to the outer peripheral surface. A lubricant evaluation device that evaluates the lubrication performance of the lubricant by plastically deforming the metal test piece of (a) with respect to the bottomed fitting hole into which one end of the metal test piece is fitted and the pressing direction. A first mold having a right-angle pressing plane; (b) a second mold having an inclined pressing surface inclined in a taper shape about the axis of the metal specimen; and (c) the first mold. After the metal test piece is clamped between the mold and the second mold from both end faces with a certain stroke, the protruding load when one end of the metal test piece is protruded from the bottomed fitting hole is measured. A load sensor that detects the pressure load detected by the load sensor. Zui it and evaluating the lubrication performance of the lubricant.

  Preferably, the bottom surface of the bottomed fitting hole provided in the first mold is constituted by a front end surface of a knockout pin slidably fitted to the first mold, and the knockout pin One end portion of the metal test piece after plastic deformation is protruded from the bottom fitting hole. Thereby, the said load sensor is provided in the knockout pin.

  Preferably, the first mold is provided with a heating device for maintaining the first mold at a temperature in a processing state to which the lubricant is applied. In this way, the lubricating performance of the lubricant can be more accurately evaluated.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios, shapes, and the like of the respective parts are not necessarily drawn accurately.

  FIG. 1 is a diagram illustrating a configuration of a lubricant evaluation device 10 according to an embodiment of the present invention. This lubricant evaluation device 10 is configured in the same manner as the press device, and is provided with a lower die 14 supported by a base 12 so as to be fixed in position, and provided above the lower die 14 so as to approach the lower die 14. An upper punch 18 that is reciprocated by being fixed to a ram (not shown) movably provided in the separation direction, that is, the vertical direction, and an electric motor and a crank mechanism that is driven by the upper punch 18. A mold driving device 20 is provided for reciprocatingly driving the upper die punch 18 with a constant stroke between its raised position and lowered position. In this embodiment, the lower die 14 corresponds to the first die, and the upper die punch 18 corresponds to the second die.

  The left half of FIG. 2 shows a state where the upper die punch 18 is in its raised position, and the right half of FIG. 2 shows a state where the upper die punch 18 is in its lowered position. As shown in detail in FIG. 2, the lower die 14 has a pressing plane 22 orthogonal to the axis C of the upper die punch 18, a through hole 24 concentric with the axis C, and the through hole 24. A knockout pin 28 that is slidably fitted and driven in the direction of the axis C by a hydraulic actuator 26 is provided. The knockout pin 28 is driven by the hydraulic actuator 26 between a lower end position whose tip surface 30 is lower than the pressing plane 22 by a predetermined dimension and an upper end position higher than the pressing plane 22 by a predetermined dimension. In the standby period and the pressing period, the front end surface 30 is at a lower end position lower than the pressing flat surface 22 by a predetermined dimension, so that the front end surface 30 that functions as the bottom surface and the inner peripheral surface of the through hole 24 that functions as the inner wall surface Thus, a bottomed fitting hole B is formed. That is, in the standby period and the pressing period, a bottomed fitting hole B concentric with the axis C is provided at the center of the pressing plane 22 of the lower mold 14.

  A distal end portion of the knockout pin 28 is provided with a first load sensor 32 for detecting a protruding load of the knockout pin 28, that is, a load applied to the distal end surface 30. One end portion (lower end portion) of a cylindrical metal test piece A after plastic deformation, which will be described later, press-fitted into the bottomed fitting hole B is fitted to the bottomed fitting hole by the tip surface 30 of the knockout pin 28. It protrudes from inside B. The protruding load at this time is detected by the first load sensor 32. The first load sensor 32 is constituted by, for example, a well-known load cell.

  A plurality of heaters 34 are embedded in an outer peripheral position separated from the through hole 24 in the lower mold 14 by a predetermined distance, and the lower mold 14 is provided by a temperature control device 36 that supplies driving power to the plurality of heaters 34. Is maintained at a preset temperature. The temperature control device 36 is supplied with a signal indicating an actual temperature detected by a temperature sensor (not shown) provided in the lower mold 14 and a signal indicating a target temperature set by a temperature setting device (not shown). The output energy of the plurality of heaters 34 is adjusted so that the temperature matches the target temperature. The target temperature is usually set to a metal temperature at the time of plastic working at which application of the lubricant to be evaluated is expected.

  The upper die punch 18 includes a punch 38 having a pressing surface having a cross-sectional shape enlarged in FIG. 3 at the front end surface, a punch holder 40 that holds the punch 38, and a circle between the lower die 14 and the punch 38. A second load sensor 42 provided on the punch 38 is provided for detecting the load in the direction of the axis C that the punch 38 receives during the press working for clamping the columnar metal specimen A, that is, the pressing load of the punch 38. The second load sensor 42 is also constituted by, for example, a load cell.

  The front surface of the punch 38 is concentric with the axis C and is adjacent to the outer peripheral side of the receiving surface 44, and a receiving surface 44 that forms the bottom surface of a relatively shallow positioning hole having the same diameter as the through hole 24. An inclined pressing surface 46 that inclines in a taper shape with the axis C as a center so as to go to the lower mold 14 side toward the outer peripheral side, and a plane that is adjacent to the outer peripheral side of the inclined pressing surface 46 and orthogonal to the axial center C. There is provided an annular plane 48 and a relief surface 50 that is adjacent to the outer peripheral side of the annular plane 48 and is inclined in a taper shape with the axis C as the center so as to move away from the lower mold 14 toward the outer peripheral side. . The angle α with respect to the plane perpendicular to the axis C of the inclined pressing surface 46 is for smoothly increasing the molding load, that is, the pressing load when the intermediate portion protrudes in a flange shape toward the outer peripheral side during plastic deformation of the metal test piece A. It is set within a range of 5 ° to 70 °.

  Returning to FIG. 1, the control device 52 is constituted by a microcomputer, a sequencer or the like, and is a program preset in response to a signal from the start button 54 operated for each press start operation, for example, FIG. The operation of the mold drive device 20 and the hydraulic actuator 26 is controlled according to the flowchart shown in FIG. That is, first, as a preparatory step for evaluating the lubricant, one end of a cylindrical metal test piece A with the lubricant applied to the outer peripheral surface is inserted into the bottomed fitting hole B of the lower mold 14, and the mutual Positioned so that the axes are aligned. The left side of FIG. 2 shows this state.

In this state, in step S1 of FIG. 4 (hereinafter, step is omitted), it is determined based on a signal from the activation button 54 whether or not an evaluation start operation, that is, a press activation operation has been performed. If the determination in S1 is negative, this routine is terminated. If the determination is affirmative, in S2 corresponding to the plastic processing step or the plastic processing means, a one-cycle press procedure is started and the die driving device is started. 20, the upper die punch 18, that is, the punch 38 is lowered to the lowered position shown on the right side of FIG. 2, and a cylindrical metal test piece A having one end fitted into the bottomed fitting hole B of the lower die 14 is formed. A predetermined amount of plastic deformation is performed by being compressed in a constant pressing period of about one second by a predetermined distance set in the direction of the axis C. In this plastic working, that is, press working, as shown on the right side of FIG. 2, plastic deformation is performed in which the intermediate portion of the metal test piece A is projected in a flange shape toward the outer peripheral side. Next, in S3 corresponding to the pressing load detecting step or the pressing load detecting means, the pressing load W _P (ton) of the punch 38 at this time is sequentially detected based on the signal from the second load sensor 42, and the maximum value is obtained. A certain maximum pressing load W _Pmax is stored. The pressing load W _P is increased with elapsed from the beginning of the pressing period, it reaches a maximum pressure load W _Pmax the end of the pressing period.

In subsequent S4, the punch 38 is returned to the raised position shown on the left side of FIG. Next, in S5 corresponding to the protruding step or the protruding means, the knockout pin 28 is protruded from the lower mold 14 by the hydraulic actuator 26 to a position where the tip surface 30 is higher than the pressing plane 22, and is plastically deformed in S2. The lower end portion of the metal test piece A biting into the bottomed fitting hole B of the lower die 14 is protruded from the lower die 14 and is raised and separated. Subsequently, in S6 corresponding to the protruding load detecting step or the protruding load detecting means, the protruding load W _E (ton) of the knockout pin 28 at that time is sequentially detected based on the signal from the first load sensor 32, and the maximum value thereof is detected. The maximum protruding load W _Emax is stored. The projected load W _E reaches the maximum projected load W _Emax soaring at the beginning of the ejection period, then decreases towards zero.

In subsequent S7, the knockout pin 28 is returned to the initial lowered position shown on the left side of FIG. In S8 corresponding to the evaluation step or the evaluation means, the lubricant applied to the side surface of the cylindrical metal specimen A can be evaluated using the maximum pressing load _WPmax and the maximum protruding load _WEmax. Determination or display is performed. For example, the maximum pressing load W _Pmax and the maximum protruding load W _Emax are output as a graph indicating the difference between the types of lubricants, or the maximum pressing load W _Pmax or the maximum protruding load W _Emax is set to a preset evaluation reference value. It is determined whether or not the difference is exceeded, and the determination result is displayed for each type of lubricant. The maximum pressing load W _Pmax reflects the change in the friction coefficient of the surface of the metal specimen A during plastic deformation and the presence or absence of seizure. The maximum protruding load W _Emax reflects seizure properties.

  A different lubricant is applied to the side surface, that is, the outer peripheral surface of a metal test piece having a diameter of 11.83 mmφ and a height of 24 mm, which is made of S15C and having a hardness of HRB67. The depth is 3 mm, the diameter of the receiving surface 44 of the punch 38 is 12.5 mmφ, the width dimension [= (outer diameter−inner diameter) / 2] of the inclined pressing surface 46 is 4 mmφ, the angle α of the inclined pressing surface 46 is 30 °, A lubricant evaluation test performed using the lubricant evaluation apparatus 10 shown in FIG. 1 in which the width dimension of the annular plane 48 is 3 mmφ will be described below.

  First, a metal test piece A1 with a zinc phosphate coating on the side, a metal test piece A2 with a Na soap coating on the side, and a metal test piece A3 with an S-based oil coating on the side. Samples were prepared. The metal test piece A1 has a zinc phosphate coating formed by a zinc phosphate coating treatment. The metal test piece A2 was prepared by attaching a sodium soap film to a wire, drawing a calcium stearate powder to a diameter of 11.83 mmφ, and cutting it to a length of 24 mm. The metal test piece A3 is a lubricating oil using sulfur (30 wt%) as an extreme pressure additive, and has an S-based oil film formed by brushing.

Next, the temperature of the lower die 14 is maintained at 150 ° C., and the three kinds of metal test pieces A1, A2, A3 are placed on the bottom surface of the bottomed fitting hole B of the lower die 14 and the receiving surface 44 of the punch 38 at the lowered position. The maximum pressing load _WPmax when plastically deforming by changing the gap between the gap G and the gap G (mm) was measured. FIG. 5 shows the above measurement results in two-dimensional coordinates of the test piece height H (mm) and the maximum pressing load _WPmax after plastic deformation. Since the metal specimen height H after plastic deformation corresponds to the maximum surface enlargement ratio R _Smax , the maximum surface enlargement is obtained in place of the axis indicating the specimen height H after plastic deformation in the two-dimensional coordinates of FIG. An axis indicating the ratio R _Smax may be used. The axis indicating the metal specimen height H after plastic deformation is shown on the lower side of the two-dimensional coordinates in FIG. 5, and the axis showing the maximum surface enlargement ratio R _Smax is shown on the upper side.

6 and 7 are diagrams analyzed using a finite element method for explaining the surface expansion ratio R _S and the maximum surface expansion ratio R _Smax . 6 and 7, the fine points P are equidistant by being attached to the boundaries of the finite elements equally divided in the direction of the axis C on the side surface of the cylindrical metal specimen before plastic deformation. The figure shows a state in which the side surfaces are deformed into flanges after plastic deformation, resulting in unequal intervals. FIG. 6 shows a state in the middle of plastic deformation due to pressing, and FIG. 7 shows a state where the plastic deformation has further progressed. The surface expansion ratio R _S is a ratio of change in the annular surface area for each section sandwiched between a pair of points P, and is the area after plastic deformation / the area before plastic deformation. In FIG. 6, the surface expansion ratio R _S of the section a is 1.01, the surface expansion ratio R _S of the section b is 5.65, and the surface expansion ratio R _S of the section b is the maximum surface expansion ratio R _Smax. It is. In FIG. 7, the surface expansion ratio R _S of the section c is 2.01, the surface expansion ratio R _S of the section d is 13.8, and the surface expansion ratio R _S of the section d is the maximum surface expansion ratio. R _Smax .

In FIG. 5, □ indicates the value of the metal test piece A1 with the zinc phosphate coating applied to the side surface, ○ indicates the value of the metal test piece A2 with the Na soap coating applied to the side surface, and Δ mark Indicates the value of the metal test piece A3 with the S-based oil film deposited on the side surface. The broken line in FIG. 5 shows a sample in which the set gap G is plastically deformed under the same conditions. Even when the gap G between the lower die 14 and the punch 38 is the same and plastic deformation is performed, the post-pressing test piece height H is different due to the influence of the lubricant. In this respect, the lubricant can be evaluated based on the post-pressing test piece height H, but the change in the post-pressing test piece height H due to the change in the lubricant is relatively small. The one-dot chain line in FIG. 5 shows the relationship between the post-pressing test piece height H and the maximum pressing load _WPmax when the same lubricant is used. The change of the maximum pressing load W _Pmax due to the change of the lubricant is relatively large, and the lubricant is easily evaluated by comparing the maximum pressing load W _Pmax or by comparing with a predetermined determination value. .

As described above, according to the lubricant evaluation method of the present embodiment, the plasticity in which the metal test piece A is clamped from both end faces with a constant stroke so that the intermediate portion of the metal test piece A protrudes in a flange shape toward the outer peripheral side. processing performed, lubrication evaluating the lubrication performance of the lubricant on the basis of the pressure load W _P for metal test piece a at that time, the side surface on the deposited lubricant an intermediate portion of the metal test piece a Since the performance closely affects the plastic working that protrudes in the form of a flange from the intermediate portion to the outer peripheral side, the lubricating performance of the lubricant applied to the side surface of the metal material can be accurately evaluated during the plastic working. .

  Further, according to the lubricant evaluation method of the present embodiment, the plastic working is performed using the lower mold (first mold) 14 having the pressing plane 22 perpendicular to the pressing direction and the axis C of the metal test piece A. Since the metal test piece A is sandwiched between the punch (second mold) 38 having the inclined pressing surface 46 inclined in a taper shape as the center, the distance from the metal test piece A becomes narrower. Since it protrudes in a flange shape from the intermediate part of the metal test piece A through the gap between the lower die 14 and the punch 38 to the outer peripheral side, the plastic deformation load reflecting the lubricating performance of the lubricant is applied to the pressing load of the die. As a result, the lubrication performance of the lubricant applied to the side surface of the metal material during plastic working can be more accurately evaluated.

  Further, according to the lubricant evaluation method of the present embodiment, the metal test piece A is clamped with a constant stroke from both end faces in a state where one end of the metal test piece A is fitted in the bottomed fitting hole B, and a metal test is performed. Lubricant based on the protruding load when plastic processing is performed to project the intermediate part of the piece A to the outer peripheral side in a flange shape, and one end part (lower end part) of the metal test piece A is projected from the bottom fitting hole B From the firm interference fit state between the outer peripheral surface of one end portion of the metal test piece A and the inner peripheral surface of the bottomed fitting hole B into which the metal test piece A is fitted, Since the lubricating performance of the lubricant closely affects the protruding load when one end of the metal test piece A is protruded from the fitting hole B, lubrication of the lubricant applied to the side surface of the metal material during plastic working Performance can be accurately evaluated.

  Further, according to the lubricant evaluation method of the present embodiment, the lower die having the bottoming fitting hole B into which the one end portion of the metal test piece A is fitted and the pressing plane 22 perpendicular to the pressing direction is used. The metal test piece A is sandwiched between the (first mold) 14 and a punch (second mold) 38 having an inclined pressing surface 46 inclined in a taper shape about the axis C of the metal test piece A. Since it is performed by being pressed, it protrudes in the form of a flange from the intermediate part of the metal test piece A to the outer peripheral side through the gap between the lower mold 14 and the punch 38 that becomes narrower as the distance from the metal test piece A increases. The plastic deformation load reflecting the lubrication performance of the lubricant is reflected in the pressing load of the mold, and the lubrication performance of the lubricant applied to the side surface of the metal material during plastic working can be more accurately evaluated.

  Further, according to the lubricant evaluation method of the present embodiment, the inclined pressing surface 46 is inclined with respect to a surface orthogonal to the axis C that is the pressing direction in an angle range of 5 to 70 degrees. In addition, since it protrudes in a flange shape from the intermediate part of the metal test piece A to the outer peripheral side through the gap between the lower die 14 and the punch 38 that becomes narrower as the distance from the metal test piece A, the plasticity reflects the lubricating performance of the lubricant. The deformation load is appropriately reflected in the pressing load of the mold.

  As mentioned above, although one Example of this invention was described based on drawing, this invention is applied also in another aspect.

  For example, in the above-described embodiment, the first load sensor 32 is provided at the distal end portion of the knockout pin 28, but may be provided at an intermediate portion or a proximal end portion. In addition, since the protruding load by the knockout pin 28 only needs to be detected, the first load sensor 32 detects an amount corresponding to the protruding load, for example, a hydraulic sensor for detecting the hydraulic pressure of the hydraulic cylinder 26, or the hydraulic cylinder thereof. It may be composed of a strain gauge or the like fixed to 26 attachment sites.

  Moreover, although the above-mentioned 2nd load sensor 42 was provided in the back surface of the punch 38, you may provide in the front-end | tip part. In addition, since it is only necessary to detect the pressing load by the punch 38, the second load sensor 42 constitutes a strain gauge fixed to the portion where the upper punch 18 is fixed, or the mold driving device 20. It may be configured by a drive current sensor of an electric motor.

  In addition, the pressing plane 22 of the lower mold 14 and the tip end surface of the punch 38 in the above-described embodiment may have other shapes. For example, the tip surface of the punch 38 may be formed as a flat surface, and the inclined pressing surface 46 may be formed on the pressing surface of the lower mold 14. Further, both the pressing surface of the lower mold 14 and the tip surface of the punch 38 may be flat.

In the above-described embodiment, the maximum pressing load W _Pmax or the maximum protruding load W _Emax is used for evaluating the lubricating performance of the lubricant applied to the outer peripheral surface of the metal test piece A. integrated value .SIGMA.W P pressing load W _P on the inner _or integrated value .SIGMA.W _E ejector load W _E in projecting period may be used. Integrated value .SIGMA.W _P of pressure load _{W P,} or even integrated value .SIGMA.W _E ejector load _{W E,} similarly to the maximum pressure load _{W Pmax} or the maximum projected load _{W Emax,} is deposited on the outer peripheral surface of the metal test piece A Therefore, it can be used to evaluate the lubricating performance of the lubricant. The cumulative value .SIGMA.W _P or .SIGMA.W _E is obtained by sequentially adding the pressure load W _P or protruding load W _E being sampled input at a predetermined period, for example every several ms in the microcomputer of the control device 52.

  Further, in the above-described embodiment, the punch 38 is configured to press downward toward the lower mold 14, but may be configured to press horizontally or upward.

  Although the present invention has been described in detail above, the above description is merely an embodiment, and the present invention can be implemented in various modifications and improvements based on the knowledge of those skilled in the art.

1 is an overall view illustrating a configuration of a lubricant evaluation device to which an embodiment of the present invention is applied. It is sectional drawing explaining the operating state of the lower mold | type and upper mold | type punch of the lubricant evaluation apparatus of FIG. It is sectional drawing which expands and shows the front-end | tip shape of the punch of the lubricant evaluation apparatus of FIG. It is a flowchart explaining the principal part of the action | operation of the control apparatus of FIG. It is a figure which shows the experimental result when the metal test piece to which the different lubricating oil was adhered was changed plastically by changing the gap G, respectively, Comprising: Metal test piece height H after plastic deformation and the maximum pressing load W The relationship with _Pmax is shown. It is a figure explaining the surface expansion ratio at the time of plastic deformation of a metal test piece, and shows a state in the middle of plastic deformation. It is a figure explaining the surface expansion ratio at the time of the plastic deformation of a metal test piece, Comprising: The deformation completion state which plastic deformation further advanced is shown.

Explanation of symbols

10: Lubricant evaluation device 14: Lower mold (first mold)
18: Upper die punch (second die)
22: Pressing plane 24: Through hole, 30: Front end surface (bottom fitting hole)
28: Knockout pin 46: Inclined pressing surface

Claims (5)

A lubricant evaluation method for evaluating the lubrication performance of a lubricant by plastically deforming a columnar metal test piece having a lubricant adhered to an outer peripheral surface,
Perform plastic working to project on the flange-shaped metal test piece nipped at a fixed stroke from the end faces of the intermediate portion of the metal test piece to the outer peripheral side, enlarged surface ratio and the of the metal test piece at that time A method for evaluating a lubricant, comprising evaluating the lubricating performance of the lubricant based on a pressing load on a metal test piece.   The plastic working is performed between a first mold having a pressing plane perpendicular to the pressing direction and a second mold having an inclined pressing surface inclined in a taper shape around the axis of the metal test piece. 2. The method for evaluating a lubricant according to claim 1, wherein the evaluation is performed by pressing the metal test piece. Plastic projecting the pre Symbol metal test piece at one end thereof a flange shape nipped from both end faces thereof in a state of being fitted into the bottomed fitting hole with a constant stroke of the intermediate portion of the metal test piece to the outer peripheral side 2. The method of evaluating a lubricant according to claim 1, wherein the lubricating performance of the lubricant is evaluated based on a protruding load when the metal test piece is protruded from the bottomed fitting hole.   The plastic working includes a first mold having a bottomed fitting hole into which one end of the metal test piece is fitted and a pressing plane perpendicular to the pressing direction, and a taper centered on the axis of the metal test piece. 4. The method for evaluating a lubricant according to claim 3, wherein the method is carried out by sandwiching the metal test piece with a second mold having an inclined pressing surface inclined in a shape.   The lubricant evaluation method according to claim 2 or 4, wherein the inclined pressing surface is inclined with respect to a surface orthogonal to the pressing direction in an angle range of 5 to 70 degrees.

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