JP2016215334A - Press-in device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a press-in device capable of simplifying a manufacturing process of pressing a press-in part in an opening part of a steel material.SOLUTION: A press-in device is the press-in device for pressing a press-in part 25 in an opening part 22 of a work 21, and comprises heating means 17 for executing heat treatment for reducing hardness of a sidewall around the opening part 22 by heating the sidewall around the opening part 22 of the work 21 and press-in means 13 for pressing the press-in part 25 in the opening part 22 of the work 21 after the heat treatment by the heating means 17. The press-in means 13 presses the press-in part 25 in the opening part 22 in a state of expanding an opening width of the opening part 22 of the work 21 more than an opening width in normal temperature time under a predetermined temperature condition higher than the normal temperature.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a press-fitting device.

  A press-fitting device for press-fitting a ball into an opening of a work is known. For example, a large number of openings for forming an oil passage are formed in an automobile mission case. A mission case is formed by press-fitting a ball into the opening to close the opening. Patent Document 1 discloses a press-fitting device that press-fits and fixes a ball into an opening of a work fixed to a support base.

Japanese Utility Model Publication No. 6-74233

Murai, Tsumura: Effects of alloying elements and carbon potential on the amount of retained austenite in carburized steel, Iron and Steel, Vol. 84 (1998) No. 1 6, PP446-451

  In the prior art, when press-fitting parts (balls) into an opening of a steel material (work), as shown in FIG. 6, after the carburizing quenching and tempering process of the steel material (step S101), the opening of the steel material is In order to suppress cracking due to the press-fitting of the press-fitted parts, the side walls around the opening are tempered to reduce the hardness (step S102). Thereafter, a finishing process for adjusting the dimensions of the opening was performed (step S103), and after this finishing process, a press-fitting part was press-fitted into the opening of the steel material (step S104). Thus, in the prior art, there is a problem that the number of processes when press-fitting a press-fit component into the opening of the steel material increases, and the manufacturing process becomes complicated.

  In view of the above problems, an object of the present invention is to provide a press-fitting device capable of simplifying the manufacturing process of press-fitting a press-fitting component into an opening of a steel material.

  The press-fitting device according to the present invention is a press-fitting device for press-fitting a press-fitting component into an opening of a steel material, and heats the side wall around the opening of the steel material to reduce the hardness of the side wall around the opening. First heating means for performing the heat treatment, and press-fitting means for press-fitting the press-fitting component into the opening of the steel material after the heat treatment by the first heating means. In the state where the opening width of the opening of the steel material is larger than the opening width at normal temperature under a predetermined temperature condition higher than normal temperature by the heat of the heat treatment by the first heating means, The part is press-fitted into the opening. The predetermined temperature condition is that the opening width of the steel material having a minimum opening width assumed to correspond to a processing tolerance of the opening width of the opening portion of the steel material that is in a room temperature state after the heat treatment is reduced. The temperature is equal to or higher than a temperature necessary for the opening of the steel material to be deformed so as to expand to the minimum value of the opening width required for press-fitting the press-fitting part into the opening.

  In the present invention, after performing a heat treatment to reduce the hardness of the side wall around the opening of the steel material, the opening width of the steel material opening is larger than the opening width at the normal temperature under a predetermined temperature condition higher than the normal temperature. In this state, the press-fitting component is press-fitted into the opening. Here, the predetermined temperature condition is that the opening width of the steel material having the minimum opening width assumed to correspond to the processing tolerance of the opening portion of the steel material at normal temperature is the opening width required for press-fitting the press-fitting component into the opening portion. The temperature is equal to or higher than the temperature necessary for the opening to be deformed so as to expand to the minimum value. Thus, in the present invention, the press-fitting component is press-fitted into the opening in a state where the side wall around the opening of the steel material is heated and the opening width of the opening of the steel material is larger than the opening width at normal temperature. . Therefore, the finishing process (step S103 in FIG. 6) for adjusting the dimension of the opening required in the prior art can be omitted, and the manufacturing process for press-fitting the press-fitting parts into the opening of the steel material is simplified. be able to.

  The press-fitting device according to the present invention may further include a second heating unit that heats the press-fitting component. When the predetermined temperature condition is higher than the point A1 of the steel material, the press-fitting unit After the heating means 2 heats the press-fitting part to a temperature higher than the Ms point of the steel material, the press-fitting part may be press-fitted into the opening.

  When the predetermined temperature condition is higher than the point A1 of the steel material, when the press-fitting part is press-fitted into the opening of the steel material, the side wall around the opening is rapidly cooled to generate martensite (causing delayed fracture). There is a fear. However, by pre-heating the press-fitted part to a temperature higher than the Ms point of the steel material, it is possible to prevent the side wall around the opening from being rapidly cooled when the press-fitted part is press-fitted into the steel part opening. And the generation of martensite can be suppressed.

  The press-fitting device according to the present invention may further include a second heating unit that heats the press-fitting component, and when the press-fitting unit press-fits the press-fitting component into the opening of the steel material, The heating means may heat and soften the press-fitted parts.

  Thus, by press-fitting and press-fitting the press-fitting component, the press-fitting component can be deformed when the press-fitting component is press-fitted into the opening of the steel material. Therefore, the press-fit load required when press-fitting a press-fit component into the opening of the steel material can be reduced.

  The press-fitting device according to the present invention further includes press-fitting load measuring means for measuring a press-fitting load acting between the press-fitting component and a side wall around the opening when the press-fitting component is press-fitted into the opening. The second heating means may heat the press-fitting component so that the press-fit load measured by the press-fit load measuring means is smaller than a predetermined value.

  In this way, the press-fitting load is measured using the press-fitting load measuring means, and when the measured press-fitting load is a predetermined value or more, the press-fitting part is heated to increase the deformation amount of the press-fitting part. The press-fitting load during press-fitting can be made smaller than a predetermined value. Therefore, when press-fitting a press-fitting component, it is possible to suppress a large press-fitting load from acting on the side wall around the opening, and it is possible to prevent the side wall around the opening from being damaged.

  A press-fitting device according to the present invention is a press-fitting device for press-fitting a press-fitting component into an opening of a steel material, and heats the press-fitting component in a state where the press-fitting component is in contact with a side wall around the opening. A first heat treatment is performed to heat the side wall around the opening of the steel material through the press-fitting component to reduce the hardness of the side wall around the opening, and to perform a heat treatment to soften the press-fitting component. Heating means, and press-fitting means for press-fitting the press-fitting part into the opening in a state where the press-fitting part is softened by the heat treatment for softening.

  In the present invention, the press-fitted component is press-fitted into the opening in a state where the press-fitted component is softened by the heat treatment for softening. Therefore, the press-fitting part can be deformed when the press-fitting part is press-fitted into the opening, and the processing accuracy required for the opening can be reduced. Therefore, the finishing process (step S103 in FIG. 6) for adjusting the dimension of the opening required in the prior art can be omitted, and the manufacturing process for press-fitting the press-fitting component into the opening of the steel material is simplified. be able to. In the present invention, the press-fitting component is heated in a state where the press-fitting component is in contact with the side wall around the opening, and the side wall around the opening is heat-treated through the press-fitting component. It is not necessary to provide a complicated device such as a unit, and the device configuration of the press-fitting device can be simplified.

  According to the present invention, it is possible to provide a press-fitting device capable of simplifying a manufacturing process of press-fitting a press-fitting part into an opening of a steel material.

1 is a perspective view illustrating an example of a press-fitting device according to a first embodiment. FIG. 3 is an enlarged cross-sectional view illustrating an example of a press-fitting device according to the first embodiment. 3 is a flowchart for explaining the operation of the press-fitting device according to the first embodiment; FIG. 6 is a cross-sectional view for explaining the operation of the press-fitting device according to the first embodiment. FIG. 6 is a cross-sectional view for explaining the operation of the press-fitting device according to the first embodiment. FIG. 6 is a cross-sectional view for explaining the operation of the press-fitting device according to the first embodiment. FIG. 6 is a cross-sectional view for explaining the operation of the press-fitting device according to the first embodiment. It is a figure which shows the relationship between the temperature and elongation of steel materials. It is a flowchart which shows the manufacturing process concerning a prior art. It is sectional drawing which shows an example of the press injection apparatus concerning Embodiment 2. FIG. 6 is a flowchart for explaining the operation of the press-fitting device according to the second embodiment; It is a figure which shows the relationship between the temperature of the ball | bowl at the time of press-fitting a ball | bowl in an opening part, and the hardness of the side wall around the opening part after pressing-in a ball | bowl. It is sectional drawing which shows an example of the press injection apparatus concerning Embodiment 3. FIG. 10 is a flowchart for explaining an operation of the press-fitting device according to the third embodiment. It is a figure which shows the relationship between the temperature of a ball | bowl, and hardness. FIG. 6 is a cross-sectional view illustrating an example of a press-fitting device according to a fourth embodiment. 10 is a flowchart for explaining the operation of the press-fitting device according to the fourth embodiment;

<Embodiment 1>
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a perspective view illustrating an example of a press-fitting device according to the first embodiment. FIG. 2 is an enlarged cross-sectional view illustrating an example of a press-fitting device according to the first embodiment. As shown in FIGS. 1 and 2, the press-fitting device 1 includes a servo press unit 11, an scale 12, a ram 13 (press-fitting means), a spacer 14, a chuck 15, a rotation unit 16, and a laser unit 17 (first heating means). ). In FIG. 1, the laser unit 17 is not shown.

  The spacer 14 is configured so that a work (steel material) 21 can be attached and detached. For example, a recess 18 (see FIG. 4A) is formed at the upper end of the spacer 14, and the workpiece 21 is disposed in the recess 18. The workpiece 21 is fixed to the recess 18 using a bolt or the like. The lower end portion of the spacer 14 is fixed to the chuck 15. The chuck 15 is configured to be rotatable using a rotation unit 16. For example, the rotation unit 16 is configured to be rotatable using a motor, and the workpiece 21 attached to the upper end portion of the spacer 14 rotates about the rotation shaft 31 as the rotation unit 16 rotates.

  The laser unit 17 shown in FIG. 2 irradiates the side wall 23 (see FIG. 4A) around the opening 22 of the workpiece 21 with laser light 28. At this time, by rotating the rotary unit 16 and rotating the work 21 around the rotation shaft 31, the side wall 23 around the opening 22 of the work 21 can be uniformly irradiated with the laser light 28, and the opening The side wall 23 around 22 can be heated uniformly. The laser unit 17 is configured to be able to adjust the irradiation energy of the laser light 28. Thereby, the heat processing temperature of the side wall 23 around the opening part 22 of the workpiece | work 21 can be adjusted.

  The ram 13 is configured so that a ball 25 (press-fit component) can be attached and detached. For example, the tip of the ram 13 is magnetized, and the ball 25 can be fixed to the ram 13 using magnetic force. Further, a suction mechanism may be provided at the tip of the ram 13 and the ball 25 may be fixed to the ram 13 by suction with the suction mechanism.

  The ram 13 is fixed to the scale 12. The scale 12 is configured so that the ram 13 can be attached and detached. For example, the ram 13 is replaced when the ram 13 is damaged or when a ram 13 having a different shape is used.

  The servo press unit 11 is configured to be able to move up and down the scale 12 (including the ram 13). The servo press unit 11 includes a motor and a screw (not shown), and the scale 12 is displaced vertically by rotating the screw by rotating the motor. Thereby, the ram 13 can be displaced up and down.

  Next, operation | movement of the press injection apparatus concerning this Embodiment is demonstrated using the flowchart shown in FIG. 3, and sectional drawing shown to FIG. 4A-FIG. 4D. When the ball 25 is press-fitted into the opening 22 of the work 21, first, as shown in FIG. 4A, the work 21 is attached to the recess 18 of the spacer 14 (step S1). Further, the ball 25 is attached to the tip of the ram 13 (step S2).

  Next, as shown in FIG. 4B, the side wall 23 around the opening 22 of the workpiece 21 is irradiated with laser light 28 to heat the side wall 23 (step S3). Specifically, after rotating the rotation unit 16 and rotating the workpiece 21 around the rotation shaft 31, the laser unit 28 irradiates the side wall 23 around the opening 22 of the workpiece 21 with the laser beam 28. Thereby, the heat processing (tempering) for reducing the hardness of the side wall 23 around the opening 22 of the workpiece 21 can be performed.

  At this time, the heat treatment temperature and heat treatment time of the side wall 23 can be arbitrarily set. For example, the heat treatment temperature and the heat treatment time are set such that the hardness of the side wall 23 is equal to or lower than a predetermined hardness. Here, the predetermined hardness is a hardness that can prevent the side wall 23 around the opening 22 from being cracked by the press-fitting of the press-fitting parts. In addition, since heat processing conditions depend on the composition of the steel materials which comprise the workpiece | work 21, it is preferable to obtain | require heat processing conditions previously according to the composition of steel materials. After the heat treatment of the side wall 23 around the opening 22 is completed, the irradiation of the laser light 28 is stopped and the rotation of the rotating unit 16 is stopped.

  Next, as shown in FIG. 4C, the ball 25 is press-fitted into the opening 22 of the workpiece 21 (step S4). Specifically, the scale 12 is lowered by rotating the motor of the servo press unit 11. As a result, the ram 13 is lowered and the ball 25 can be press-fitted into the opening 22 of the workpiece 21.

  In the press-fitting device 1 according to the present embodiment, the ball 25 is press-fitted into the opening 22 of the work 21 when the temperature of the side wall 23 around the opening 22 of the work 21 is a predetermined temperature condition. Here, the predetermined temperature condition means that the opening width of the workpiece 21 having the minimum opening width assumed to correspond to the processing tolerance of the opening width of the opening portion 22 of the workpiece 21 that is in a normal temperature state after the temperature is lowered after the heat treatment. The temperature is equal to or higher than the temperature necessary for deforming the opening 22 of the work 21 so as to expand to the minimum value of the opening width required for press-fitting the ball 25 into the opening 22. That is, by setting the temperature of the side wall 23 around the opening 22 to be equal to or higher than a predetermined temperature, the opening width of the opening 22 can be widened, and the ball 25 can be press-fitted into the opening 22.

  For example, the processing tolerance T1 of the opening 22 of the workpiece 21 after the finishing process (step S103) of the prior art shown in FIG. 6 is set to 0.03 mm. Further, the machining tolerance T2 of the opening 22 of the workpiece 21 when the finishing process (step S103) is not performed is set to 0.2 mm. This processing tolerance T2 corresponds to the processing tolerance when the opening 22 is formed in the workpiece 21, and the above-mentioned “processing tolerance of the opening width of the opening 22 of the workpiece 21 in a room temperature state when the temperature is lowered after the heat treatment. Is supported. Further, if the machining tolerance of the opening 22 enlarged by omitting the finishing process is ΔT, the enlarged machining tolerance ΔT is the case where the machining tolerance T2 of the opening 22 when the finishing process is not performed and the finishing process is performed. Therefore, [Delta] T = T2-T1 = 0.17 mm.

  And in this Embodiment, the temperature of the side wall 23 around the opening part 22 of the workpiece | work 21 shall be more than predetermined temperature, and the workpiece | work 21 assumed corresponding to the processing tolerance T2 of the opening part 22 of the workpiece | work 21 is demonstrated. The opening 22 of the work 21 is deformed so that the opening width (minimum opening width) is expanded to the minimum value of the opening width required for press-fitting the ball into the opening 22. In other words, the amount of expansion of the opening width of the opening portion 22 (corresponding to the amount of elongation of the steel material in FIG. 5) is made larger than the enlarged processing tolerance ΔT (0.17 mm).

  Specifically, when the diameter of the opening 22 is φ6 mm, the diameter of the opening 22 is φ6 ± 0.2 mm in consideration of the processing tolerance T2 (0.2 mm). Therefore, the minimum opening width assumed corresponding to the processing tolerance (normal temperature state) of the opening width of the opening 22 is φ5.8 mm (= 6 mm−0.2 mm). Further, the minimum value of the opening width required for press-fitting the ball 25 into the opening 22 is 0.03 mm because the machining tolerance T1 of the opening 22 of the work 21 when the finishing process (step S103) is performed. , Φ5.97 (= 6 mm−0.03 mm). Therefore, the ball 25 can be press-fitted into the opening 22 by heating the workpiece 21 so that the opening width increases from φ5.8 mm to φ5.97.

  To explain using the enlarged machining tolerance ΔT, when the diameter of the opening 22 is φ6 mm, the enlarged machining tolerance ΔT is 0.17 mm, so the diameter of the opening 22 is φ6 ± 0.17 mm. For example, when the diameter of the opening 22 is φ5.83 mm (= 6 mm−0.17 mm), in order to press-fit the ball 25 (φ6 mm), (6π−5.83π) ÷ 6π × 100 = 2. An elongation of 8% is required. FIG. 5 is a diagram showing the relationship between the temperature and elongation of the steel material (SCR 40) constituting the workpiece 21. As shown in FIG. As shown in FIG. 5, in order for the workpiece 21 to extend by 2.8% or more, the workpiece 21 may be heated to a temperature of 550 ° C. or more.

  At this time, the side wall 23 around the opening 22 is cooled after the heating step (step S3) and before the press-fitting step (step S4) is started, and the side wall 23 is heated in the heating step (step S3). It is preferable to set the temperature at that time higher. In the present embodiment, the processing tolerance of the ball 25 is assumed to be negligibly small compared to the processing tolerance of the workpiece 25 (for example, about ± 1 μm).

  As described above, in the press-fitting device 1 according to the present embodiment, the temperature of the side wall 23 around the opening 22 is set to a predetermined temperature or higher in the press-fitting step (step S4). Can be made larger than the processing tolerance ΔT of the enlarged opening 22 by omitting the finishing process, and the ball 25 can be press-fitted into the opening 22. Therefore, the finishing process (step S103 in FIG. 6) that is necessary in the prior art becomes unnecessary. Moreover, the plastic deformability of the side wall 23 around the opening 22 is improved by heating the side wall 23 around the opening 22. Therefore, since the opening 22 is deformed when the ball 25 is press-fitted into the opening 22, it is possible to prevent the side wall 23 around the opening 22 from being cracked when the ball 25 is press-fitted.

  Note that the processing tolerance of the opening 22 after the heat treatment (step S3) corresponds to the above-described processing tolerance T2. In this embodiment, the amount of the opening width of the opening 22 is equal to that of the opening 22. You may make it press-fit the ball | bowl 25 in the opening part 22 of the workpiece | work 21 when it is more than the temperature which becomes larger than the process tolerance T2 (T2> (DELTA) T). To explain using the above example, the ball 25 is press-fitted into the opening 22 of the workpiece 21 when the amount of the opening width of the opening 22 is equal to or higher than the processing tolerance T2 (0.2 mm). May be. A state in which the opening width of the opening 22 is larger than the processing tolerance T2 of the opening 22 after the heat treatment corresponds to a case where the tolerance by finishing is zero.

  In step S4, after the ball 25 is press-fitted into a predetermined position of the opening 22 of the workpiece 21, the ram 13 is raised as shown in FIG. 4D. Thereafter, the workpiece 21 into which the ball 25 has been press-fitted is cooled for handling (step S5). At this time, when the workpiece 25 is cooled, the opening 22 of the workpiece 25 contracts, and the ball 25 is firmly fixed to the opening 22. That is, the effect of shrink fitting is obtained.

  In the steps described above, the timing for starting the lowering of the ram 13, the timing for stopping the irradiation of the laser light 28, and the timing for stopping the rotation of the rotating unit 16 may overlap each other.

  In the prior art, when the ball is press-fitted into the opening of the workpiece, as shown in FIG. 6, after the carburizing and tempering process (step S101) of the workpiece, the side wall around the opening of the workpiece is pressed into the ball. In order to suppress cracking due to, the side walls around the opening were tempered to reduce the hardness (step S102). Thereafter, a finishing process for adjusting the size of the opening is performed (step S103). After the finishing process, the ball is press-fitted into the opening of the work (step S104). Thus, in the prior art, there is a problem that the number of processes when the ball is press-fitted into the opening of the work increases, and the manufacturing process becomes complicated. Further, in the prior art, since the laser tempering process (step S102) and the press-fitting process (step S104) are performed by different machines, there is a problem that the number of facilities increases.

  On the other hand, in the press-fitting device 1 according to the present embodiment, the side wall 23 around the opening 22 of the workpiece 21 is irradiated with laser light 28 to heat the side wall 23 around the opening 22 (step S3), and then When the temperature of the side wall 23 around the opening 22 is a predetermined temperature condition, the ball 25 is press-fitted into the opening 22 of the workpiece 21. Thus, in the press-fitting device 1 according to the present embodiment, the side wall 23 around the opening 22 of the work 21 is heated, and the opening width of the opening 22 of the work 21 is larger than the opening width at normal temperature. , The ball 25 is press-fitted into the opening 22. Therefore, it is possible to omit the finishing process (step S103 in FIG. 6) for adjusting the size of the opening necessary in the conventional technique, and simplify the manufacturing process of press-fitting the ball 25 into the opening 22 of the work 21. Can be In other words, the processing tolerance of the opening 22 expanded by omitting the finishing process can be compensated for by the increase in the amount of opening width of the opening 22 due to the temperature rise. In the prior art, the laser tempering process (step S102) and the press-fitting process (step S104) are performed by different machines. However, in the press-fitting device 1 according to the present embodiment, these steps can be performed by a single device. Therefore, the number of facilities can be reduced as compared with the prior art.

  Further, in the press-fitting device 1 according to the present embodiment, since the laser beam 28 is used when heating the side wall 23 around the opening 22 of the work 21, after the heating of the side wall 23 around the opening 22 is finished. The ball 25 can be quickly pressed into the opening 22. For example, when a high-frequency heating device is used for heating the side wall 23 around the opening 22, the coil is heated close to the side wall 23 around the opening 22. In this case, after the heating of the side wall 23 around the opening 22, it is necessary to move the coil before the ball 25 is press-fitted into the opening 22. The temperature of the side wall 23 decreases. However, when the opening 22 is heated using the laser beam 28 as in the present embodiment, the ball 25 can be pressed into the opening 22 immediately after the laser beam 28 is stopped. Therefore, the ball 25 can be pressed into the opening 22 before the temperature of the side wall 23 around the opening 22 is lowered.

  With the invention according to the present embodiment described above, it is possible to provide a press-fitting device that can simplify the manufacturing process of press-fitting a press-fitting component into an opening of a steel material.

<Embodiment 2>
Next, a second embodiment of the present invention will be described. FIG. 7 is a cross-sectional view illustrating an example of a press-fitting device according to the second embodiment. As shown in FIG. 7, the press-fitting device according to the present embodiment is different from the press-fitting device 1 according to the first embodiment in that it includes a heating unit 35 (second heating unit) for heating the ball 25. Different. Other than this, since it is the same as the press-fitting device 1 described in the first embodiment, a duplicate description will be omitted as appropriate.

  Since the workpiece 21 is formed using a steel material, if the temperature condition when the workpiece 21 is heat-treated is inappropriate, martensite that causes delayed fracture is generated. This martensite is produced | generated when the austenite generated by heating steel materials more than A1 point (A1 transformation temperature) is rapidly cooled. Martensite is a solid solution in which carbon penetrates into iron crystals of a body-centered tetragonal lattice, and has the property of being hard and brittle. For this reason, it is necessary to prevent martensite from being formed in the opening 22 of the workpiece 21.

  However, in the first embodiment, when the heat treatment temperature of the side wall 23 around the opening 22 of the work 21 in step S3 of FIG. When the pressure is inserted, the side wall 23 around the opening 22 is rapidly cooled. For this reason, there is a problem that martensite is formed on the side wall 23 around the opening 22.

  Therefore, in the press-fitting device according to the present embodiment, when the heat treatment temperature of the side wall 23 around the opening 22 of the workpiece 21 is equal to or higher than the A1 point, after heating the ball 25 to a temperature higher than the Ms point of the steel material, A ball 25 is press-fitted into the opening 22 of the work 21.

  As shown in FIG. 7, the heating means 35 is provided so as to surround the ram 13. The heating means 35 can be configured using, for example, a heating wire. By heating the ram 13 using the heating means 35, heat is transferred from the ram 13 to the ball 25 attached to the tip of the ram 13, and the ball 25 is heated. The temperature of the side wall 23 around the opening 22 and the temperature of the ball 25 can be measured using, for example, a radiation thermometer (not shown).

  Next, operation | movement of the press injection apparatus concerning this Embodiment is demonstrated using the flowchart of FIG. First, the work 21 is attached to the spacer 14 (step S11). Further, the ball 25 is attached to the tip of the ram 13 (step S12).

  Next, the side wall 23 around the opening 22 of the workpiece 21 is irradiated with laser light 28 to heat the side wall 23 (step S13). Thereby, the heat processing (tempering) for reducing the hardness of the side wall 23 around the opening 22 of the workpiece 21 can be performed. In the present embodiment, it is assumed that the heat treatment temperature of the side wall 23 around the opening 22 of the work 21 is equal to or higher than the A1 point.

  Next, the ball 25 is heated using the heating means 35 (step S14). At this time, the ball 25 is heated to a temperature higher than the Ms point of the steel material constituting the workpiece 21. Here, the Ms point varies depending on the composition of each element constituting the steel material. For example, the Ms point can be obtained using the following equation (see Non-Patent Document 1).

  Ms (K) = 812-423C-30.4Mn-17.7Ni-12. 1Cr-7.5Mo + (10Co-7.5Si) Formula 1

  Here, C is mass% of C, Mn is mass% of Mn, Ni is mass% of Ni, Cr is mass% of Cr, Mo is mass% of Mo, Co is mass% of Co, Si is mass of Si. %.

  And after heating the ball | bowl 25 to the temperature higher than Ms point of steel materials, the ball | bowl 25 is press-fit in the opening part 22 of the workpiece | work 21 (step S15). Specifically, the scale 12 is lowered by rotating the motor of the servo press unit 11. As a result, the ram 13 is lowered and the ball 25 can be press-fitted into the opening 22 of the workpiece 21.

  While the ball 25 is descending toward the opening 22, the temperature of the ball 25 is decreased. Therefore, the temperature of the ball 25 may be set higher in advance so as to be higher than the Ms point of the steel material when the ball 25 reaches the opening 22. Alternatively, while the ball 25 is descending toward the opening 22, the heating means 35 may be used to continue heating the ball 25 so that the temperature is higher than the Ms point of the steel material.

  Thereafter, the workpiece 21 into which the ball 25 has been press-fitted is cooled for handling (step S16). At this time, when the workpiece 25 is cooled, the opening 22 of the workpiece 25 contracts, and the ball 25 is firmly fixed to the opening 22.

  FIG. 9 is a diagram showing the relationship between the temperature of the ball 25 when the ball 25 is press-fitted into the opening 22 and the hardness of the side wall 23 around the opening 25 after the ball 25 is press-fitted. In the example shown in FIG. 9, the composition in the vicinity of the surface of the side wall 23 around the opening 22 of the steel material is 0.2% carbon, 0.25% Si, 0.73% Mn, and 1.05 Cr. %, Ni is 0.13%, Mo is 0%, and Co is 0%. In this case, the Ms point in the vicinity of the surface of the opening 22 is 162 ° C. from Equation 1 above. The A1 point of the steel material is 727 ° C.

  When the side wall 23 around the opening 22 of the workpiece 21 is heated to 850 ° C. (temperature of A1 or higher) and then heat-treated, and then the room temperature ball 25 is press-fitted, the side wall 23 around the opening 22 is rapidly cooled. Is done. At this time, since austenite in the steel material is quenched and martensite is generated, the hardness in the vicinity of the surface of the side wall 23 around the opening 22 becomes 780 (Hv) and becomes hard as shown in FIG.

  On the other hand, if the ball 25 heated to 400 ° C. is pressed after the side wall 23 around the opening 22 of the work 21 is heated to 850 ° C. (temperature of A1 point or higher) and then heated around 400 ° C., Since the side wall 23 is not rapidly cooled, the formation of martensite can be suppressed. For this reason, as shown in FIG. 9, the hardness near the surface of the side wall 23 around the opening 22 can be set to about 400 (Hv), which is lower than the target value of 440 (Hv). can do.

  As described above, when the temperature when the side wall 23 around the opening 22 is heat-treated (step S13) is higher than the point A1 of the steel material, the opening 22 is pressed when the ball 25 is press-fitted into the opening 22. There is a possibility that martensite (which causes delayed fracture) is generated by rapidly cooling the side wall 23 around. However, in the press-fitting device according to the present embodiment, the ball 25 is heated in advance to a temperature higher than the Ms point of the steel material (step S14), and the ball 25 is opened when the ball 25 is press-fitted into the steel material opening 22. It can suppress that the side wall 23 around the part 22 is cooled rapidly, and can suppress the production | generation of a martensite.

  In the above description, the configuration in which the ball 25 is heated after the ball 25 is attached to the ram 13 has been described. However, in the press-fitting device according to the present embodiment, the pre-heated ball 25 may be attached to the ram 13 and then the ball 25 may be press-fitted into the opening 22. In this case, it is necessary to set the temperature of the ball 25 higher in consideration of the time for attaching the ball 25 to the ram 13 and the time for transporting the ball 25 to the opening 22.

<Embodiment 3>
Next, a third embodiment of the present invention will be described. FIG. 10 is a cross-sectional view illustrating an example of a press-fitting device according to the third embodiment. As shown in FIG. 10, the press-fitting device according to the present embodiment includes a heating unit 35 (second heating unit) for heating the ball 25 and the opening 22 when the ball 25 is press-fitted into the opening 22. The press-fitting device 1 according to the first embodiment is different from the press-fitting device 1 according to the first embodiment in that a press-fitting load measuring unit 37 for measuring a press-fitting load acting between the side wall 23 and the ball 25 is provided. Other than this, since it is the same as the press-fitting device described in the first embodiment, a duplicate description will be omitted as appropriate.

  In the press-fitting device according to the present embodiment, when the ball 25 is press-fitted into the opening 22, the ball 25 is heated and softened using the heating means 35. Thus, by heating and softening the ball 25, the ball 25 can be deformed (plastically deformed) when the ball 25 is press-fitted into the opening 22. Therefore, it is possible to reduce the press-fitting load required when the ball 25 is press-fitted into the opening 22.

  At this time, a press-fitting load measuring means 37 for measuring a press-fitting load acting between the side wall 23 around the opening 22 and the ball 25 when the ball 25 is press-fitted into the opening 22 is provided. The ball 25 may be heated so that the press-fitted load is smaller than a predetermined value.

  As described above, the press-fitting load is measured using the press-fitting load measuring means 37, and when the measured press-fitting load is equal to or greater than a predetermined value, the ball 25 is heated to increase the deformation amount of the ball 25. The press-fitting load when press-fitting can be made smaller than a predetermined value. Therefore, it is possible to suppress a large press-fitting load from acting on the side wall 23 around the opening 22 when the ball 25 is press-fitted, and to prevent the side wall 23 around the opening 22 from being damaged.

  As shown in FIG. 10, the heating means 35 is provided so as to surround the periphery of the ram 13. The heating means 35 can be configured using, for example, a heating wire. By heating the ram 13 using the heating means 35, heat is transferred from the ram 13 to the ball 25 attached to the tip of the ram 13, and the ball 25 is heated.

  The press-fit load measuring means 37 is provided between the ram 13 and the scale 12. When the ball 25 is press-fitted into the opening 22, the ball 25 receives a reaction force from the side wall 23 around the opening 22. This reaction force is transmitted from the ram 13 to the equal 12. The press-fit load measuring means 37 can measure the press-fit load acting between the side wall 23 around the opening 22 and the ball 25 by measuring the force transmitted from the ram 13 to the scale 12. The press-fit load measuring means 37 can be configured using, for example, a pressure sensor.

  Next, operation | movement of the press injection apparatus concerning this Embodiment is demonstrated using the flowchart of FIG. First, the work 21 is attached to the spacer 14 (step S21). Further, the ball 25 is attached to the tip of the ram 13 (step S22). Next, the side wall 23 around the opening 22 of the workpiece 21 is irradiated with laser light 28 to heat the side wall 23 around the opening 22 (step S23). Thereby, the heat processing (tempering) for reducing the hardness of the side wall 23 around the opening 22 of the workpiece 21 can be performed.

  Next, the ball 25 is press-fitted into the opening 22 of the workpiece 21 while heating the ball 25 (step S24). Specifically, the ball 25 is heated using the heating means 35. In addition, the scale 12 is lowered by rotating the motor of the servo press unit 11. Thereby, the ball 25 can be press-fitted into the opening 22 of the work 21 while the ball 25 is heated.

  The press-fitting device 1 controls the temperature of the ball 25 using the heating unit 35 while monitoring the press-fitting load acting between the side wall 23 around the opening 22 and the ball 25 by the press-fitting load measuring unit 37 ( Step S25). Specifically, the heating unit 35 heats the ball 25 so that the press-fit load measured by the press-fit load measuring unit 37 is smaller than a predetermined value. In other words, the heating unit 35 increases the temperature of the ball 25 when the press-fit load measured by the press-fit load measuring unit 37 is larger than a predetermined value. Thereby, the ball is softened, and the press-fitting load when the ball 25 is press-fitted into the opening 22 can be reduced.

  Thereafter, until the press-fitting of the ball is completed (until the ball 25 reaches a predetermined position of the opening 22), the operations in steps S24 to S25 are repeated (step S26: No). Then, after the press-fitting of the ball is finished (step S26: Yes), the work 21 into which the ball 25 is press-fitted is cooled for handling (step S27). At this time, when the workpiece 25 is cooled, the opening 22 of the workpiece 25 contracts, and the ball 25 is firmly fixed to the opening 22.

  FIG. 12 is a diagram showing the relationship between the temperature and hardness of the ball 25. FIG. 12 shows a case where SUJ2 (high carbon chrome bearing steel) is used as the material of the ball 25. As shown in FIG. 12, as the temperature of the ball 25 increases, the hardness of the ball 25 decreases. In the present embodiment, the temperature of the ball 25 may be determined with reference to data as shown in FIG.

  As described above, the press-fitting load is measured using the press-fitting load measuring means 37, and when the measured press-fitting load is equal to or greater than a predetermined value, the ball 25 is heated to increase the deformation amount of the ball 25. The press-fitting load when press-fitting can be made smaller than a predetermined value. Therefore, it is possible to suppress a large press-fitting load from acting on the side wall 23 around the opening 22 when the ball 25 is press-fitted, and to prevent the side wall 23 around the opening 22 from being damaged.

  In the above description, the configuration in which the ball 25 is heated after the ball 25 is attached to the ram 13 has been described. However, in the press-fitting device according to the present embodiment, the ball 25 heated in advance may be attached to the ram 13. Thus, by heating the ball 25 in advance, it is possible to shorten the heating time until the ball 25 is softened after the ball 25 is attached to the ram 13.

  Moreover, although the volume of the ball | bowl 25 expand | swells by heating the ball | bowl 25, it can be said that the influence of the softening of the ball | bowl 25 is larger in this Embodiment. In addition, with respect to the opening 22, it can be said that the influence of the increase in the amount of expansion of the opening 22 is greater than the effect of softening by heating the side wall 23 around the opening 22. Therefore, in the present embodiment, the press-fitting load when the ball 25 is press-fitted can be reduced by heating the side wall 23 and the ball 25 around the opening 22.

  Also, in the press-fitting device according to the present embodiment, the same effect as that obtained by the press-fitting device according to the second embodiment may be obtained. That is, when the temperature at the time of heat-treating the side wall 23 around the opening 22 (step S23) is higher than the point A1 of the steel material, the side wall 23 around the opening 22 when the ball 25 is press-fitted into the opening 22 is used. May be rapidly cooled to produce martensite (causing delayed fracture). However, in the press-fitting device according to the present embodiment, when the ball 25 is press-fitted into the opening 22 of the workpiece 21 while heating the ball 25 (step S24), the ball 25 is set to a temperature higher than the Ms point of the steel material in advance. By heating, when the ball 25 is press-fitted into the opening 22 of the steel material, the side wall 23 around the opening 22 can be prevented from being rapidly cooled, and the generation of martensite can be suppressed. . In this case, it is assumed that the control temperature of the ball 25 controlled in step S25 is higher than the Ms point of the steel material.

<Embodiment 4>
Next, a fourth embodiment of the present invention will be described. FIG. 13 is a cross-sectional view showing an example of a press-fitting device according to the present embodiment. In the press-fitting apparatus described in the first to third embodiments, the heat treatment is performed on the side wall 23 around the opening 22 of the workpiece 21 by irradiating the laser beam 28 (see FIG. 4B). However, in the press-fitting device according to the present embodiment, heat treatment is performed on the side wall 23 around the opening 22 of the workpiece 21 using the ball 25 instead of using the laser beam. As shown in FIG. 13, the press-fitting device according to the present embodiment is not provided with the laser unit 17 (see FIG. 2), and the heating means 35 for heating the ball 25 (the first embodiment in the present embodiment). The heating means is different from the press-fitting device according to the first embodiment. Other than this, since it is the same as the press-fitting device 1 described in the first embodiment, a duplicate description will be omitted as appropriate.

  As shown in FIG. 13, the heating means 35 is provided so as to surround the ram 13. The heating means 35 can be configured using, for example, a heating wire. By heating the ram 13 using the heating means 35, heat is transferred from the ram 13 to the ball 25 attached to the tip of the ram 13, and the ball 25 is heated. The heating means 35 heats the ball 25 in a state where the ball 25 is in contact with the side wall 23 around the opening 22, and heat-treats the side wall 23 around the opening 22 through the ball 25. That is, in the press-fitting device according to the present embodiment, heat is transferred from the heated ball 25 to the side wall 23 around the opening 22 by heat conduction, so that the heat treatment is performed on the side wall 23 around the opening 22. it can.

  Next, operation | movement of the press injection apparatus concerning this Embodiment is demonstrated using the flowchart of FIG. First, the work 21 is attached to the spacer 14 (step S31). Further, the ball 25 is attached to the tip of the ram 13 (step S32). Next, the ball 25 is heated (step S33). Then, the ball 25 is held in contact with the side wall 23 around the opening 22 of the workpiece 21 and heat-treated on the side wall 23 around the opening 22 (see step S34: FIG. 13). Thereby, the heat processing (tempering) for reducing the hardness of the side wall 23 around the opening 22 of the workpiece 21 can be performed. In the present embodiment, heating of the ball 25 may be started after the ball 25 is brought into contact with the side wall 23 around the opening 22 of the workpiece 21. That is, step S33 may be included in step S34.

  At this time, the heat treatment temperature and heat treatment time of the side wall 23 around the opening 22 can be arbitrarily set. For example, the heat treatment temperature and the heat treatment time are set such that the hardness of the side wall 23 around the opening 22 is equal to or lower than a predetermined hardness. Here, the predetermined hardness is a hardness that can prevent the side wall 23 around the opening 22 from being cracked by the press-fitting of the press-fitting parts.

  After the above heat treatment is completed, the heated ball 25 (that is, a heat-treated ball for softening the ball 25) is press-fitted into the opening 22 of the workpiece 21 (step S35). Thereafter, the workpiece 21 into which the ball 25 has been press-fitted is cooled for handling (step S36). At this time, when the workpiece 25 is cooled, the opening 22 of the workpiece 25 contracts, and the ball 25 is firmly fixed to the opening 22. That is, the effect of shrink fitting is obtained.

  In the press-fitting device according to the present embodiment, the ball 25 is press-fitted into the opening 22 while the ball 25 is softened by the heat treatment for softening (step S35). Therefore, the ball 25 can be deformed when the ball 25 is press-fitted into the opening 22, and the processing accuracy required for the opening 22 can be reduced. Therefore, the finishing process (step S103 in FIG. 6) for adjusting the dimension of the opening required in the prior art can be omitted, and the manufacturing process for press-fitting the press-fitting component into the opening of the steel material is simplified. be able to. Further, in the press-fitting device according to the present embodiment, the ball 25 is heated while the ball 25 is in contact with the side wall 23 around the opening 22, and the side wall 23 around the opening 22 is passed through the ball 25. Has been heat treated. Therefore, the laser unit 17 (see FIG. 2) can be omitted as compared with the press-fitting device according to the first embodiment, so that the device configuration of the press-fitting device can be simplified.

  In particular, in the press-fitting device according to the present embodiment, when the heat treatment temperature of the side wall 23 around the opening 22 is relatively low, that is, the margin for reducing the hardness of the side wall around the opening 22 (hardness reduction width). Effective when is low.

  Although the present invention has been described with reference to the above embodiment, the present invention is not limited only to the configuration of the above embodiment, and within the scope of the invention of the claims of the present application. It goes without saying that various modifications, corrections, and combinations that can be made by those skilled in the art are included.

1 Press-fitting device 11 Servo press unit 12 Equal 13 Ram (Press-fitting means)
14 Spacer 15 Chuck 16 Rotating unit 17 Laser unit 21 Workpiece (steel material)
22 Opening 23 Side wall 25 Ball (Press-fit part)
28 Laser beam 31 Rotating shaft 35 Heating means 37 Press-fit load measuring means

Claims (5)

A press-fitting device for press-fitting a press-fitting component into an opening of a steel material,
First heating means for heating a side wall around the opening of the steel material and performing a heat treatment for reducing the hardness of the side wall around the opening;
Press-fitting means for press-fitting the press-fitting component into the opening of the steel after the heat treatment by the first heating means,
In the state where the opening width of the opening of the steel material is larger than the opening width at normal temperature under a predetermined temperature condition higher than normal temperature by the heat of the heat treatment by the first heating means, Press fit the part into the opening,
The predetermined temperature condition is that the opening width of the steel material having a minimum opening width assumed to correspond to a processing tolerance of the opening width of the opening portion of the steel material that is in a room temperature state after the heat treatment is reduced. The temperature is equal to or higher than the temperature required for the opening of the steel material to deform so as to expand to the minimum value of the opening width required for press-fitting the press-fitting component into the opening.
Press-fitting device. A second heating means for heating the press-fitting component;
When the predetermined temperature condition is higher than the A1 point of the steel material, the press-fitting means is configured such that after the second heating means heats the press-fitted part to a temperature higher than the Ms point of the steel material, Press-fitting press-fit parts,
The press-fitting device according to claim 1. A second heating means for heating the press-fitting component;
When the press-fitting means press-fits the press-fit component into the opening of the steel material, the second heating means heats and softens the press-fit component,
The press-fitting device according to claim 1. A press-fitting load measuring means for measuring a press-fitting load acting between the press-fitting component and a side wall around the opening when the press-fitting component is press-fitted into the opening;
The second heating means heats the press-fitting component so that the press-fit load measured by the press-fit load measuring means is smaller than a predetermined value.
The press-fitting device according to claim 3. A press-fitting device for press-fitting a press-fitting component into an opening of a steel material,
The press-fitting component is heated in a state where the press-fitting component is in contact with the side wall around the opening, and the side wall around the opening of the steel material is heated through the press-fitting component to surround the opening. A first heating means for performing a heat treatment for reducing the hardness of the side wall and a heat treatment for softening the press-fit component;
Press-fitting means for press-fitting the press-fit component into the opening in a state where the press-fit component is softened by the heat treatment for softening,
Press-fitting device.

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