Lubricant coating method

Abstract

To improve the blow-off property of a lubricant.SOLUTION: A lubricant supplying step S110 of supplying a lubricant to a lower mold 21 and an upper mold 22 that forge a crankshaft, and a gas injection step S120 of injecting a gas to at least the lower mold 21 by a gas injection mechanism 32, wherein the gas injection mechanism 32 includes a plurality of lower mold-side gas injection nozzles 421 that inject the gas to the lower mold 21, in the gas injection step S120, the gas injection mechanism 32 performs the first state in which the plurality of lower-mold-side gas injection nozzles 421 are moved in the mold longitudinal direction at the first speed by the first distances P1 shorter than the predetermined intervals DD1 between the plurality of lower-mold-side gas injection nozzles 421, and the second state in which the moving speed of the plurality of lower-mold-side gas injection nozzles 421 in the mold longitudinal direction is made slower than the first speed for a predetermined time, and injects the gas from the plurality of lower-mold-side gas injection nozzles at least in the second state.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to a lubricant application method. [Background technology]

[0002] Patent Documents 1 to 5 describe lubricant application methods for applying lubricant to a forging die. In these conventional techniques, a liquid lubricant is applied to the forging die to prevent the workpiece from sticking to the forging die. If a forging press is performed with lubricant accumulated in the forging die, a quality defect known as underfill occurs in the forged workpiece. Therefore, in these conventional techniques, after the lubricant is applied to the forging die, air is blown onto the forging die (particularly the lower die located on the lower side in the direction of gravity) to blow off the lubricant accumulated in the forging die. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2011 / 078133 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-321033 [Patent Document 3] Japanese Patent Application Laid-Open No. 2008-132513 [Patent Document 4] Japanese Patent Application Laid-Open No. 2008-207252 [Patent Document 5] Japanese Patent Application Laid-Open No. 2002-102984 Summary of the Invention [Problem to be solved by the invention]

[0004] Because crankshafts are long parts, it is preferable that a forging die for forging crankshafts be provided with a plurality of gas injection nozzles in the longitudinal direction of the forging die for injecting air toward the forging die.Furthermore, it is preferable that the plurality of gas injection nozzles be moved in the longitudinal direction of the forging die to prevent insufficient air injection into areas of the forging die located between the plurality of gas injection nozzles.

[0005] However, because crankshafts are parts with complex shapes with many irregularities, the forging dies used to forge crankshafts also have complex shapes with many irregularities, so simply moving multiple gas injection nozzles in the longitudinal direction of the forging die may not be enough to blow off the lubricant locally.

[0006] The present invention has been made in view of the above background, and aims to improve the blow-off properties of a lubricant in a lubricant application method for applying a lubricant to a forging die when forging a crankshaft. [Means for solving the problem]

[0007] One aspect of the present invention is a lubricant application method for applying a lubricant to a forging die when forging a crankshaft, comprising: a lubricant supplying step of supplying the lubricant to a lower die disposed on a lower side in the direction of gravity and an upper die disposed on an upper side in the direction of gravity of the forging die; a gas injection step of injecting gas onto at least the lower die using a gas injection mechanism to blow away the lubricant accumulated on the lower die, the gas injection mechanism includes a plurality of lower mold-side gas injection nozzles that inject the gas onto the lower mold, and is configured to be movable in the longitudinal direction of the lower mold, the plurality of lower die-side gas injection nozzles are arranged at predetermined intervals in the longitudinal direction of the lower die, In the gas injection step, the gas injection mechanism a first state in which the plurality of lower mold side gas injection nozzles are moved in the longitudinal direction of the lower mold by a first distance shorter than the predetermined interval at a first speed; a second state in which the moving speed of the plurality of lower mold-side gas injection nozzles in the longitudinal direction of the lower mold is made slower than the first speed for a predetermined time; The lubricant application method includes injecting the gas from the plurality of lower die-side gas injection nozzles at least in the second state. [Effects of the Invention]

[0008] According to this aspect, in the second state, gas is injected from the plurality of lower-die-side gas injection nozzles while moving them at a slower speed than in the first state, so that the lubricant can be blown away more effectively in the second state than when gas is injected while the plurality of lower-die-side gas injection nozzles are moved at the same speed as in the first state. The second state is performed while the plurality of lower-die-side gas injection nozzles move a distance shorter than the predetermined interval between the plurality of lower-die-side gas injection nozzles, so that it is possible to minimize the occurrence of localized areas in the forging die where the lubricant cannot be sufficiently blown away.

[0009] As described above, in a lubricant application method for applying a lubricant to a forging die when forging a crankshaft, the blow-off properties of the lubricant can be improved. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a diagram showing the configuration of a crankshaft. [Figure 2] 1 is a side view showing the overall configuration of a forging die and a lubricant application device according to an embodiment; [Figure 3] FIG. 4 is a side view showing a nozzle portion and a lower die of the lubricant application device. [Figure 4] IV arrow view of Figure 3. [Figure 5] VV cross section of Figure 3. [Figure 6] FIG. 10 is a side view illustrating the movement of the lubricant application device in the longitudinal direction of the mold. [Figure 7] 1 is a flowchart showing one of a plurality of hot forging steps. [Figure 8] 5 is a time chart showing the operation of the lubricant application device in a lubricant application process. [Figure 9] FIG. 10 is a first diagram illustrating the operation of the lubricant application device in the lubricant application step. [Figure 10] FIG. 10 is a second diagram illustrating the operation of the lubricant application device in the lubricant application step. [Figure 11] FIG. 10 is a third diagram illustrating the operation of the lubricant application device in the lubricant application step. [Figure 12] 5A and 5B are cross-sectional views illustrating the effects of the lubricant application method according to the embodiment. [Figure 13] FIG. 4 is a fourth diagram illustrating the operation of the lubricant application device in the lubricant application step. DETAILED DESCRIPTION OF THE INVENTION

[0011] The lubricant application method is a lubricant application method for applying lubricant to a forging die when forging a crankshaft, and includes a lubricant supplying step of supplying the lubricant to a lower die arranged on the lower side in the direction of gravity and an upper die arranged on the upper side in the direction of gravity of the forging die, and a gas injection step of injecting gas into at least the lower die with a gas injection mechanism to blow away the lubricant accumulated in the lower die, wherein the gas injection mechanism includes a plurality of lower die-side gas injection nozzles that inject the gas into the lower die, and is configured to be movable in the longitudinal direction of the lower die, and the plurality of lower die-side gas injection nozzles are arranged at predetermined intervals in the longitudinal direction of the lower die, and in the gas injection step, the gas injection mechanism A first state is performed in which the plurality of lower mold-side gas injection nozzles are moved in the longitudinal direction of the lower mold at a first speed by a first distance shorter than the predetermined interval, and a second state is performed in which the movement speed of the plurality of lower mold-side gas injection nozzles in the longitudinal direction of the lower mold is made slower than the first speed for a predetermined time, and the gas is injected from the plurality of lower mold-side gas injection nozzles at least in the second state.

[0012] In the lubricant application method, the first state and the second state may be repeated multiple times in the gas injection step, thereby further improving the blow-off properties of the lubricant.

[0013] In the lubricant application method, in the gas injection step, the gas injection mechanism may continue to inject the gas from the plurality of lower die-side gas injection nozzles in both the first state and the second state, thereby further improving the blowing-off performance of the lubricant.

[0014] In the lubricant application method, in the second state, the gas injection mechanism may stop movement of the plurality of lower-die-side gas injection nozzles in the longitudinal direction of the lower die. Since gas can be stably sprayed onto the lower die in the second state, the blowing-off performance of the lubricant can be reliably improved.

[0015] In the lubricant application method, in the gas injection step, after the first state and the second state are completed, the gas may be injected from the lower mold-side gas injection nozzles while the lower mold-side gas injection nozzles are moved so that the lower mold-side gas injection nozzles are retracted from between the lower mold and the upper mold. This makes it possible to extend the time for which the gas is blown onto the lower mold, thereby further improving the blowing-off performance of the lubricant.

[0016] In the lubricant application method, the plurality of lower-die-side gas injection nozzles are configured to be movable in the direction of gravity together with a lubricant injection nozzle that injects the lubricant toward the upper and lower dies in the lubricant supplying step, and in the gas injection step, the lubricant injection nozzle and the plurality of lower-die-side gas injection nozzles may be moved downward in the direction of gravity relative to the lubricant supplying step. Since gas can be reliably sprayed onto the lower die, where lubricant is likely to accumulate due to the influence of gravity, the blowing-off performance of the lubricant can be further improved.

[0017] In the lubricant application method, in the gas injection step, the lubricant injection nozzle and the plurality of lower die-side gas injection nozzles may be moved to positions closer to the lower die than to the upper die. This allows the gas to be more reliably sprayed onto the lower die, where lubricant tends to accumulate due to the influence of gravity, thereby further improving the ability to blow off the lubricant.

[0018] In the lubricant application method, the gas may be injected from the lower die-side gas injection nozzles while the lubricant injection nozzle and the lower die-side gas injection nozzles are moved downward in the direction of gravity relative to the lubricant supply step in the gas injection step. This makes it possible to extend the time for which the gas is blown onto the lower die, thereby further improving the blowing-off performance of the lubricant.

[0019] (One embodiment) 1. Shape of workpiece W A workpiece W formed by a forging die to which the lubricant application method of this embodiment is applied will be described with reference to Fig. 1. The workpiece W is a crankshaft. As shown in Fig. 1, the crankshaft that is the workpiece W is for an in-line four-cylinder engine, for example. The workpiece W is not limited to a crankshaft for an in-line four-cylinder engine, and various crankshafts can be used.

[0020] The crankshaft, which is the workpiece W, includes a plurality of journals 11a to 11e, a plurality of pins 12a to 12d, and a plurality of counterweights 13a to 13h. If the number of cylinders differs, the numbers of journals, pins, and counterweights also differ.

[0021] 2. Overall configuration of the forging die 20 and lubricant application device 30 The overall configuration of the forging die 20 and the lubricant application device 30 will be described with reference to Fig. 2. The forging die 20 is a forging die used in one of a plurality of hot forging processes for forming a crankshaft, which is the workpiece W. In Fig. 2, the up and down arrows indicate the up and down directions in the direction of gravity.

[0022] As shown in Figure 2, the forging die 20 includes a lower die 21 arranged on the lower side in the direction of gravity and an upper die 22 arranged on the upper side in the direction of gravity. The lower die 21 is detachably mounted on the upper surface of a bolster of a forging press (not shown). The upper die 22 is detachably mounted on the lower surface of a slide of the forging press (not shown). A lower die forming surface 21a, which is the forming surface of the lower die 21, and an upper die forming surface 22a, which is the forming surface of the upper die 22, have complex concave shapes corresponding to the shape of the crankshaft, which is the workpiece W.

[0023] Lubricant application device 30 is a device that applies lubricant to lower mold molding surface 21 a and upper mold molding surface 22 a, and injects lubricant (liquid) and gas (air in this example) onto lower mold molding surface 21 a and upper mold molding surface 22 a. That is, lubricant application device 30 is a device that integrally comprises a lubricant injection mechanism 31 that injects lubricant onto lower mold molding surface 21 a and upper mold molding surface 22 a, and a gas injection mechanism 32 that injects gas onto lower mold molding surface 21 a and upper mold molding surface 22 a.

[0024] The lubricant is applied to the lower mold forming surface 21a and the upper mold forming surface 22a to prevent the workpiece W from sticking to the lower mold forming surface 21a and the upper mold forming surface 22a. The gas is sprayed onto the lower mold forming surface 21a and the upper mold forming surface 22a to remove excess lubricant remaining on the lower mold forming surface 21a and the upper mold forming surface 22a.

[0025] If forging press is performed with lubricant accumulated on the lower die forming surface 21a and the upper die forming surface 22a, a quality defect known as undercutting will occur in the workpiece W, so gas is sprayed onto the lower die forming surface 21a and the upper die forming surface 22a to blow away the lubricant accumulated on the lower die forming surface 21a and the upper die forming surface 22a, so that the lubricant is applied in the form of a liquid film to the lower die forming surface 21a and the upper die forming surface 22a. The gas sprayed onto the lower die forming surface 21a and the upper die forming surface 22a is not limited to air, and may be any gas that can blow away the lubricant accumulated on the lower die forming surface 21a and the upper die forming surface 22a.

[0026] The lubricant application device 30 has a nozzle unit 40, a nozzle drive unit 50, and a control device 60. The nozzle unit 40 injects a lubricant (liquid) and a gas (air in this example) onto the lower mold molding surface 21 a and the upper mold molding surface 22 a.

[0027] The nozzle driving unit 50 has a driving mechanism for moving the nozzle unit 40 in the longitudinal direction of the lower mold 21 and the upper mold 22 (hereinafter referred to as the mold longitudinal direction) and in the direction of gravity (hereinafter referred to as the up-down direction). The mold longitudinal direction coincides with the longitudinal direction of the workpiece W set in the lower mold 21 (i.e., the overall length direction of the crankshaft).

[0028] The control device 60 controls the nozzle driving unit 50 for moving the nozzle unit 40 and controls the injection of the lubricant and gas from the nozzle unit 40 .

[0029] 3. Detailed configuration of the nozzle section 40 The detailed configuration of the nozzle unit 40 will be described with reference to Figures 3, 4, 5, and 6. The nozzle unit 40 has a plurality of lower die-side lubricant injection nozzles 411, a plurality of upper die-side lubricant injection nozzles 412, a plurality of lower die-side gas injection nozzles 421, and a plurality of upper die-side gas injection nozzles 422.

[0030] Lubricant is sprayed toward the lower mold molding surface 21a from the plurality of lower mold side lubricant spray nozzles 411. Lubricant is sprayed toward the upper mold molding surface 22a from the plurality of upper mold side lubricant spray nozzles 412. Gas (air in this example) is sprayed toward the lower mold molding surface 21a from the plurality of lower mold side gas spray nozzles 421. Gas (air in this example) is sprayed toward the upper mold molding surface 22a from the plurality of upper mold side gas spray nozzles 422.

[0031] The plurality of lower die side lubricant injection nozzles 411 and the plurality of lower die side gas injection nozzles 421 are arranged on the lower surface side of the nozzle part 40. The plurality of upper die side lubricant injection nozzles 412 and the plurality of upper die side gas injection nozzles 422 are arranged on the upper surface side of the nozzle part 40.

[0032] The plurality of lower die side lubricant injection nozzles 411 and the plurality of upper die side lubricant injection nozzles 412 are arranged in two rows in the longitudinal direction of the mold. The plurality of lower die side gas injection nozzles 421 and the plurality of upper die side gas injection nozzles 422 are arranged in a row in the longitudinal direction of the mold.

[0033] More specifically, the plurality of lower die-side lubricant jet nozzles 411 and the plurality of upper die-side lubricant jet nozzles 412 are disposed symmetrically with respect to the center line of the lower die 21 and the upper die 22 in the short side direction of the lower die 21 and the upper die 22 (hereinafter referred to as the mold short side direction), and are disposed side by side in the mold long side direction. The plurality of lower die-side gas jet nozzles 421 and the plurality of upper die-side gas jet nozzles 422 are disposed on the center line of the lower die 21 and the upper die 22 in the mold short side direction, and are disposed side by side in the mold long side direction.

[0034] 4 is a view of the nozzle unit 40 as seen from above in the direction of gravity, showing the arrangement of the multiple upper die-side lubricant jet nozzles 412 and the multiple upper die-side gas jet nozzles 422. The basic arrangement of the multiple lower die-side lubricant jet nozzles 411 and the multiple lower die-side gas jet nozzles 421 is similar to the arrangement of the multiple upper die-side lubricant jet nozzles 412 and the multiple upper die-side gas jet nozzles 422, so a view of the nozzle unit 40 as seen from below in the direction of gravity is omitted.

[0035] In this example, the plurality of lower mold-side gas injection nozzles 421 and the plurality of upper mold-side gas injection nozzles 422 are arranged, with some exceptions, at a predetermined interval P1 (hereinafter referred to as nozzle interval P1) in the mold longitudinal direction. In this example, the nozzle interval P1 is 50 mm.

[0036] 3 and 5, the spray angles of the lubricant sprayed from the plurality of lower die-side lubricant spray nozzles 411 and the plurality of upper die-side lubricant spray nozzles 412 are indicated by two-dot chain lines. The number, arrangement, and spray angles of the plurality of lower die-side lubricant spray nozzles 411 and the plurality of upper die-side lubricant spray nozzles 412 are selected so that the lubricant is applied to the entire lower die molding surface 21 a and the entire upper die molding surface 22 a.

[0037] The nozzle drive unit 50 moves the nozzle unit 40 in the longitudinal direction of the mold, so that the nozzle unit 40 can move between a position where it is retracted from between the lower mold 21 and the upper mold 22 (solid line position in Figure 6) and a position where it is inserted between the lower mold 21 and the upper mold 22 (dotted line position in Figure 6).

[0038] The nozzle driving unit 50 moves the nozzle unit 40 in the vertical direction, thereby making it possible to change the vertical distance between the nozzle unit 40 and the lower mold 21 and the upper mold 22.

[0039] 3. Overall structure of the forging process The following describes one of the multiple hot forging processes for forming a crankshaft, which is the workpiece W. As shown in Fig. 7, one of the multiple hot forging processes is composed of a lubricant application process S100, a workpiece carrying-in process S200, a forging press process S300, and a workpiece carrying-out process S400.

[0040] In the lubricant application step S100, with the upper mold 22 open relative to the lower mold 21, a lubricant application device 30 is used to apply a lubricant to the lower mold molding surface 21a and the upper mold molding surface 22a. The lubricant application step S100 is made up of a lubricant supply step S110 and a gas injection step S120. In the lubricant supply step S110, a lubricant is supplied to the lower mold molding surface 21a and the upper mold molding surface 22a. In the gas injection step S120, gas is injected onto the lower mold molding surface 21a and the upper mold molding surface 22a. The gas injection step S120 is performed to blow away lubricant that has accumulated on the lower mold molding surface 21a and the upper mold molding surface 22a.

[0041] In this example, in the lubricant supply step S110, the lubricant is supplied by spraying it onto the lower mold molding surface 21a and the upper mold molding surface 22a, but the method of supplying the lubricant to the lower mold molding surface 21a and the upper mold molding surface 22a is not limited to spraying.

[0042] In the workpiece carrying-in step S200, the workpiece W is carried in and set on the lower die forming surface 21a with the upper die 22 open relative to the lower die 21. In the forging press step S300, with the workpiece W set on the lower die forming surface 21a, the upper die 22 is closed and a predetermined pressure is applied to form the workpiece W, and then the upper die 22 is opened. In the workpiece carrying-out step S400, with the upper die 22 open relative to the lower die 21, the formed workpiece W is carried out from the lower die forming surface 21a.

[0043] 4. Detailed explanation of the lubricant application process S100 8 shows a time chart of the operation of the lubricant application device 30 in the lubricant application step S100. In the lubricant application step S100, with the upper die 22 open relative to the lower die 21, the lubricant application device 30 sequentially performs the following operations: (1) forward movement, (2) forward end stop and lubricant spray, (3) downward movement and air blow, (4) downward end stop and air blow, (5) first state (nozzle movement and air blow) first time, (6) second state (stop and air blow) first time, (7) first state (nozzle movement and air blow) second time, (8) second state (stop and air blow) second time, (9) first state (nozzle movement and air blow) third time, (10) second state (stop and air blow) third time, (11) backward movement and air blow, and (12) backward end stop.

[0044] Of the operations (1) to (12) of the lubricant application device 30 in the lubricant application process S100, (1) forward movement and (2) forward movement end stop / lubricant injection are lubricant supply processes S110 that supply lubricant to the lower mold 21 and the upper mold 22.

[0045] Among the operations (1) to (12) of the lubricant application device 30 in the lubricant application process S100, (3) descent and air blow, (4) descent end stop and air blow, (5) first state (nozzle movement and air blow) first time, (6) second state (stop and air blow) first time, (7) first state (nozzle movement and air blow) second time, (8) second state (stop and air blow) second time, (9) first state (nozzle movement and air blow) third time, (10) second state (stop and air blow) third time, (11) retreat and air blow, and (12) retreat end stop are gas injection processes S120 in which gas is injected onto the lower mold 21 and the upper mold 22.

[0046] That is, in the lubricant application step S100, a lubricant supply step S110 and a gas injection step S120 are carried out consecutively.

[0047] In the (1) forward movement, the nozzle part 40 moves from a position where it has retreated from between the lower mold part 21 and the upper mold part 22 (the position indicated by the solid line in FIG. 6) in the mold longitudinal direction as shown in FIG. 9 to enter between the lower mold part 21 and the upper mold part 22. At this time, the position of the nozzle part 40 in the vertical direction is midway between the lower mold part 21 and the upper mold part 22. In other words, the center position of the nozzle part 40 in the vertical direction is equidistant from the lower mold part 21 and the upper mold part 22.

[0048] In this example, the mold open distance DO, which is the distance between the lower mold 21 and the upper mold 22 when the upper mold 22 is open relative to the lower mold 21, is 500 mm. Therefore, the lower mold side distance DL1, which is the distance between the center position of the nozzle part 40 in the vertical direction and the lower mold 21, is 250 mm, and the upper mold side distance DU1, which is the distance between the center position of the nozzle part 40 in the vertical direction and the upper mold 22, is also 250 mm.

[0049] In the operation (2) of stopping the forward movement end and applying lubricant, the nozzle unit 40 stops at the forward movement end position in the longitudinal direction of the mold (the position shown in FIG. 9), and the plurality of lower die lubricant spray nozzles 411 and the plurality of upper die lubricant spray nozzles 412 spray lubricant toward the lower mold molding surface 21a and the upper mold molding surface 22a. The lubricant is sprayed for a predetermined time (1.0 second in this example). As a result, the lubricant is supplied to the entire lower mold molding surface 21a and the upper mold molding surface 22a. In this example, the forward movement end position of the nozzle unit 40 is a position where the tip 40a of the nozzle unit 40 coincides with the end face 21b of the lower mold 21 in the longitudinal direction of the mold.

[0050] 10, in the operation of (3) downward air blow, the nozzle part 40 moves downward and gas (air in this example) is sprayed toward the lower mold molding surface 21 a and the upper mold molding surface 22 a from the plurality of lower mold-side gas spraying nozzles 421 and the plurality of upper mold-side gas spraying nozzles 422. As a result, part of the excess lubricating liquid is blown away and removed from the lower mold molding surface 21 a and the upper mold molding surface 22 a by the gas.

[0051] In the operation (4) of stopping the lower end and blowing air, the downward movement of the nozzle unit 40 is stopped, and gas (air in this example) is sprayed from the lower die-side gas injection nozzles 421 and the upper die-side gas injection nozzles 422 toward the lower die molding surface 21a and the upper die molding surface 22a. In this example, as shown in FIG. 10 , the downward movement of the nozzle unit 40 is stopped when the lower die inter-nozzle distance DL2, which is the distance between the nozzle unit 40 and the lower die 21, reaches 100 mm. As a result, the nozzle unit 40 is closer to the lower die 21 than to the upper die 22. The reason for positioning the nozzle unit 40 closer to the lower die 21 than to the upper die 22 is that, while lubricating oil naturally falls from the upper die molding surface 22a due to the effect of gravity, lubricating oil is likely to accumulate on the lower die molding surface 21a due to the effect of gravity. That is, priority is given to blowing the gas onto the lower die molding surface 21a rather than onto the upper die molding surface 22a, in order to reliably blow away excess lubricating oil that has accumulated on the lower die molding surface 21a.

[0052] (5) In the first state (nozzle movement / air blow) operation, as shown in FIG. 11 , the nozzle unit 40 retreats a first distance DD1 in the mold longitudinal direction, spraying air toward the lower mold molding surface 21a and the upper mold molding surface 22a from the multiple lower mold-side gas injection nozzles 421 and the multiple upper mold-side gas injection nozzles 422. The first distance DD1 over which the nozzle unit 40 retreats is shorter than the nozzle spacing P1. In this example, the nozzle spacing P1 is 50 mm, and the first distance DD1 over which the nozzle unit 40 retreats is 10 mm. In this example, the first time, which is the time it takes for the nozzle unit 40 to retreat the first distance DD1, is 0.4 seconds. Therefore, in this example, the first speed, which is the speed at which the nozzle unit 40 retreats, is 25 mm / s.

[0053] (6) In the first operation of the second state (stop / air blow), the retraction of the nozzle unit 40 stops, and air is injected from the lower mold-side gas injection nozzles 421 and the upper mold-side gas injection nozzles 422 toward the lower mold molding surface 21 a and the upper mold molding surface 22 a for a second time. In other words, the second speed, which is the speed at which the nozzle unit 40 retracts, becomes 0 mm / s, slower than the first speed (25 mm / s in this example), and air is injected from the lower mold-side gas injection nozzles 421 and the upper mold-side gas injection nozzles 422 toward the lower mold molding surface 21 a and the upper mold molding surface 22 a for a predetermined time. In this example, the second time for which air is injected while the retraction of the nozzle unit 40 has stopped is 0.5 seconds.

[0054] Since air is sprayed from the multiple lower mold side gas injection nozzles 421 while the nozzle section 40 is stationary, the effectiveness of blowing away lubricant accumulated on the lower mold forming surface 21a is increased compared to when air is sprayed from the multiple lower mold side gas injection nozzles 421 while the nozzle section 40 moves in the mold longitudinal direction.

[0055] Specifically, by injecting air from multiple lower mold side gas injection nozzles 421 while the nozzle section 40 is stopped, as shown in Figure 12, the air that hits the center of the lower mold molding surface 21a in the mold's short side direction is more effectively blown up in the direction of gravity from both ends of the mold's short side direction, thereby increasing the effectiveness of blowing away the lubricant that has accumulated on the lower mold molding surface 21a.

[0056] The longer the second time period during which the retraction movement of the nozzle portion 40 stops, the more the lubricant can be blown off, but the longer the cycle time will be, so it is preferable to set the second time period taking into account the allowable cycle time.

[0057] In the operation of (7) First State (Nozzle Movement / Air Blowing) Second Time, similarly to (5) First State (Nozzle Movement / Air Blowing) First Time, the nozzle unit 40 moves back a first distance DD1 in the mold longitudinal direction, while spraying air toward the lower mold molding surface 21a and the upper mold molding surface 22a from the plurality of lower mold-side gas injection nozzles 421 and the plurality of upper mold-side gas injection nozzles 422. The first distance DD1, first time, and first speed by which the nozzle unit 40 moves back are the same as those in (5) First State (Nozzle Movement / Air Blowing) First Time, and in this example are 10 mm, 0.4 seconds, and 25 mm / s, respectively.

[0058] In the operation of (8) second state (stop-air blow) second time, similarly to (6) second state (stop-air blow), the retraction movement of the lubricant injection device 100 stops, and air is injected toward the lower mold molding surface 21a and the upper mold molding surface 22a from the plurality of lower mold-side gas injection nozzles 421 and the plurality of upper mold-side gas injection nozzles 422 for a second time. The second time for which air is injected while the retraction movement of the nozzle unit 40 is stopped is the same as in (6) second state (stop-air blow) first time, and is 0.5 seconds in this example.

[0059] In the operation of (9) State 1 (nozzle movement and air blowing) third time, similarly to (5) State 1 (nozzle movement and air blowing) first time and (7) State 1 (nozzle movement and air blowing) second time, the nozzle unit 40 moves back a first distance DD1 in the mold longitudinal direction, while spraying air toward the lower mold molding surface 21a and the upper mold molding surface 22a from the plurality of lower mold-side gas injection nozzles 421 and the plurality of upper mold-side gas injection nozzles 422. The first distance DD1, first time, and first speed by which the nozzle unit 40 moves back are the same as those in (5) State 1 (nozzle movement and air blowing) first time and (7) State 1 (nozzle movement and air blowing) second time, and in this example are 10 mm, 0.4 seconds, and 25 mm / s, respectively.

[0060] In the operation of (10) second state (stop-air blow) third time, similarly to (6) second state (stop-air blow) first time and (8) second state (stop-air blow) second time, the retraction movement of the lubricant injection device 100 stops and air is injected toward the lower mold molding surface 21a and the upper mold molding surface 22a from the plurality of lower mold-side gas injection nozzles 421 and the plurality of upper mold-side gas injection nozzles 422 for a second time. The second time for which air is injected while the retraction movement of the nozzle unit 40 is stopped is the same as in (6) second state (stop-air blow) first time and (8) second state (stop-air blow) second time, and is 0.5 seconds in this example.

[0061] In this way, by repeating the first state (nozzle movement / air blow) and the second state (stop / air blow) multiple times (three times in this example), the nozzle portion 40 sprays air toward the lower mold forming surface 21a and the upper mold forming surface 22a while repeatedly moving backward and stopping.

[0062] The total nozzle movement distance, which is the distance that the nozzle unit 40 moves backward while repeating the first state (nozzle movement and air blowing) and the second state (stop and air blowing), is the first distance DD1 x the number of repetitions. In this example, the total nozzle movement distance is 30 mm (10 mm x 3 times), which is shorter than the nozzle interval P1 (50 mm in this example).

[0063] In the operation (11) of retreating and air blowing, the nozzle unit 40 continuously retreats in the mold longitudinal direction to retreat from between the lower mold 21 and the upper mold 22, while injecting air toward the lower mold molding surface 21a and the upper mold molding surface 22a from the plurality of lower mold-side gas injection nozzles 421 and the plurality of upper mold-side gas injection nozzles 422. The nozzle unit 40 retreats to the retreating end position in the mold longitudinal direction (the position retreated from between the lower mold 21 and the upper mold 22), as shown in Fig. 13 .

[0064] (12) In the operation of stopping at the retreat end, the nozzle part 40 stops at the retreat end position shown in FIG. 13, and the injection of air from the plurality of lower mold side gas injection nozzles 421 and the plurality of upper mold side gas injection nozzles 422 is stopped.

[0065] By performing the above operations, the nozzle portion 40 can supply sufficient lubricant to the entire lower mold forming surface 21a and the entire upper mold forming surface 22a, and then blow away and remove excess lubricant from the lower mold forming surface 21a and the upper mold forming surface 22a, thereby allowing the lubricant to be applied effectively in the form of a liquid film to the entire lower mold forming surface 21a and the entire upper mold forming surface 22a.

[0066] In this example, during the operations from (3) Downward Air Blow to (11) Retraction Air Blow, air is continuously sprayed toward the lower mold molding surface 21a and the upper mold molding surface 22a from the plurality of lower mold side gas injection nozzles 421 and the plurality of upper mold side gas injection nozzles 422. Therefore, the effect of blowing off excess lubricant from the lower mold molding surface 21a and the upper mold molding surface 22a can be maximized.

[0067] 10.Effects In the lubricant application method of this embodiment, the gas injection step S120 is performed in a first state (nozzle movement / air blowing) and a second state (stop / air blowing). In the first state, the nozzle unit 40 is moved in the mold longitudinal direction by a first distance DD1 at a first speed. The first distance DD1 is shorter than the nozzle interval P1. The nozzle interval P1 is the interval between the multiple lower mold-side gas injection nozzles 421 in the mold longitudinal direction. In the second state, the movement speed of the nozzle unit 40 in the mold longitudinal direction is slower than the first speed for a predetermined first time. In this example, the movement of the nozzle unit 40 in the mold longitudinal direction is stopped. Then, at least in the second state (stop / air blowing), gas is injected from the multiple lower mold-side gas injection nozzles 421.

[0068] According to this, in the second state, gas is injected from the multiple lower-die-side gas injection nozzles 421 while the moving speed of the nozzle unit 40 is slower than in the first state, so the lubricant can be blown away more effectively in the second state than when gas is injected while the nozzle unit 40 is moving at the same moving speed as in the first state. Since the second state is performed while the nozzle unit 40 moves a distance shorter than the nozzle spacing P1, it is possible to minimize the occurrence of localized areas on the lower die molding surface 21a where the lubricant cannot be sufficiently blown away. Therefore, it is possible to improve the ability to blow away the lubricant from the lower die molding surface 21a, where lubricant tends to accumulate due to the influence of gravity.

[0069] In the second state, gas is also jetted from the plurality of upper die side gas jetting nozzles 422, so that the ability to blow off the lubricant onto the upper die molding surface 22a can also be improved.

[0070] In the gas injection step S120, the first state (nozzle movement and air blowing) and the second state (stop and air blowing) are repeated multiple times, thereby further improving the blowing-off performance of the lubricant.

[0071] In the gas injection step S120, in both the first state (nozzle movement and air blowing) and the second state (stop and air blowing), gas is continuously injected from the plurality of lower die-side gas injection nozzles 421. This can further improve the blowing-off performance of the lubricant.

[0072] In the second state (stop / air blow), the movement of the nozzle part 40 in the longitudinal direction of the mold is stopped. In the second state, gas can be stably blown onto the lower mold 21, which reliably improves the blowing off performance of the lubricant.

[0073] In the gas injection step S120, after the first state (nozzle movement / air blowing) and the second state (stop / air blowing) are completed, a retreat / air blowing operation is performed. That is, gas is injected from the multiple lower mold-side gas injection nozzles 421 while the nozzle unit 40 is moved so that the nozzle unit 40 is retracted from between the lower mold 21 and the upper mold 22. Since the time for which gas is blown onto the lower mold 21 can be extended, the lubricant blowing performance can be further improved.

[0074] In the gas injection step S120, the nozzle unit 40 is moved downward in the direction of gravity relative to the lubricant supply step S110. This allows the gas to be reliably sprayed onto the lower die 21, where lubricant tends to accumulate due to the influence of gravity, thereby further improving the ability to blow off the lubricant.

[0075] In the gas injection step S120, the nozzle portion 40 is moved to a position closer to the lower mold 21 than the upper mold 22. This makes it possible to more reliably blow gas onto the lower mold 21, where lubricant tends to accumulate due to the influence of gravity, thereby further improving the ability to blow off the lubricant.

[0076] In the gas injection step S120, while the nozzle part 40 is moved downward in the direction of gravity relative to the lubricant supply step S110, gas is injected from the plurality of lower die-side gas injection nozzles 421. Since the time for which gas is blown onto the lower die 21 can be extended, the lubricant blowing-off performance can be further improved.

[0077] (Other embodiments) In the above embodiment, the retraction movement of the nozzle part 40 in the longitudinal direction of the mold is stopped in the second state (stop / air blow), but the nozzle part 40 may be retracted in the longitudinal direction of the mold at a slower speed in the second state than in the first state (nozzle movement / air blow). This can improve the blowing off performance of the lubricant in the second state compared to when the nozzle part 40 is moved at the same speed as in the first state.

[0078] In the above embodiment, during the operations from (3) Downward-Air Blow to (11) Retraction-Air Blow, air is continuously sprayed toward the lower mold molding surface 21a and the upper mold molding surface 22a from the plurality of lower mold-side gas injection nozzles 421 and the plurality of upper mold-side gas injection nozzles 422, but this is not limited to this. If air is sprayed toward the lower mold molding surface 21a from at least the plurality of lower mold-side gas injection nozzles 421 at least in the second state (Stop-Air Blow), the lubricant accumulated on the lower mold molding surface 21a can be effectively blown away.

[0079] In the above embodiment, the first state and the second state are repeated three times, but the number of times the first state and the second state are repeated may be increased or decreased as appropriate, or the first state and the second state may be repeated only once without being repeated multiple times. The more the number of repetitions, the more the lubricant blowing-off performance can be improved, but the cycle time becomes longer. Therefore, the number of repetitions should be set taking into consideration the allowable cycle time.

[0080] In the above embodiment, in the lubricant supplying step S110, the position of the nozzle portion 40 in the vertical direction is midway between the lower mold 21 and the upper mold 22, but it does not necessarily have to be midway between the lower mold 21 and the upper mold 22. The position of the nozzle portion 40 in the vertical direction may be determined taking into consideration the number of the lower mold-side lubricant spray nozzles 411 and the upper mold-side lubricant spray nozzles 412, the spray angle, the spray distance, etc.

[0081] In the above embodiment, in the gas injection process S420, the nozzle portion 40 is lowered further than in the lubricant supply process S110 to bring it closer to the lower mold 21 than the upper mold 22, but it does not necessarily have to be lowered further than in the lubricant supply process S110, and may remain at the same height as in the lubricant supply process S110.

[0082] The arrangement and numbers of the lower die-side lubricant jet nozzle 411, the upper die-side lubricant jet nozzle 412, the lower die-side gas jet nozzle 421, and the upper die-side gas jet nozzle 422 in the above embodiment are shown by way of example only and are not limited to these. The arrangement and numbers of the lower die-side lubricant jet nozzle 411, the upper die-side lubricant jet nozzle 412, the lower die-side gas jet nozzle 421, and the upper die-side gas jet nozzle 422 can be determined taking into consideration the size and shape of the lower die molding surface 21a and the upper die molding surface 22a.

[0083] The nozzle spacing P1, which is the distance in the longitudinal direction of the mold between the lower mold-side gas injection nozzle 421 and the upper mold-side gas injection nozzle 422, can also be changed as appropriate, but it is preferable to make the first distance DD1, which is the retraction distance of the nozzle part 40 in the second state (stop / air blow), shorter than the nozzle spacing P1. This is because it is possible to minimize the occurrence of localized areas on the lower mold molding surface 21a where gas is not sufficiently sprayed, thereby improving the ability to blow off the lubricant. [Explanation of symbols]

[0084] 20 Forging mold 21 Lower mold 22 Upper mold 32 Gas injection mechanism 40 Nozzle section 411 Lower die lubricant injection nozzle (lubricant injection nozzle) 412 Upper die lubricant injection nozzle (lubricant injection nozzle) 421 Lower die side gas injection nozzle S110 Lubricant supply process S120 Gas injection process double work

Claims

1. A lubricant application method for applying a lubricant to a forging die when forging a crankshaft, comprising: a lubricant supplying step of supplying the lubricant to a lower die disposed on a lower side in the direction of gravity and an upper die disposed on an upper side in the direction of gravity of the forging die; a gas injection step of injecting gas onto at least the lower die using a gas injection mechanism to blow away the lubricant accumulated on the lower die, the gas injection mechanism includes a plurality of lower mold-side gas injection nozzles that inject the gas onto the lower mold, and is configured to be movable in the longitudinal direction of the lower mold, the plurality of lower die-side gas injection nozzles are arranged at predetermined intervals in the longitudinal direction of the lower die, In the gas injection step, the gas injection mechanism a first state in which the plurality of lower mold-side gas injection nozzles are moved in the longitudinal direction of the lower mold by a first distance shorter than the predetermined interval at a first speed; a second state in which the moving speed of the plurality of lower mold-side gas injection nozzles in the longitudinal direction of the lower mold is made slower than the first speed for a predetermined time; the gas is injected from the plurality of lower die-side gas injection nozzles at least in the second state.

2. The lubricant applying method according to claim 1 , wherein the first state and the second state are repeated a plurality of times in the gas injection step.

3. 2. The lubricant application method according to claim 1, wherein in the gas injection step, the gas injection mechanism continues to inject the gas from the plurality of lower die-side gas injection nozzles in both the first state and the second state.

4. 2. The lubricant applying method according to claim 1, wherein in the second state, the gas injection mechanism stops movement of the plurality of lower die side gas injection nozzles in the longitudinal direction of the lower die.

5. 2. The lubricant application method according to claim 1, wherein in the gas injection step, after completion of the first state and the second state, the gas is injected from the plurality of lower mold-side gas injection nozzles while moving the plurality of lower mold-side gas injection nozzles so that the plurality of lower mold-side gas injection nozzles are retracted from between the lower mold and the upper mold.

6. the plurality of lower die-side gas injection nozzles are configured to be movable in the direction of gravity integrally with lubricant injection nozzles that inject the lubricant toward the upper die and the lower die in the lubricant supplying step, 4. The lubricant application method according to claim 1, wherein in the gas injection step, the lubricant injection nozzle and the plurality of lower die-side gas injection nozzles are moved downward in the direction of gravity relative to the lubricant supply step.

7. 7. The lubricant applying method according to claim 6, wherein in the gas injection step, the lubricant injection nozzle and the plurality of lower die-side gas injection nozzles are moved to positions closer to the lower die than to the upper die.

8. 7. The lubricant application method according to claim 6, wherein the gas is injected from the plurality of lower mold-side gas injection nozzles while the lubricant injection nozzle and the plurality of lower mold-side gas injection nozzles are moved downward in the direction of gravity relative to the lubricant supplying step in the gas injection step.

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