Quenching method and constraint quenching device

Abstract

A quenching method is used for a workpiece which comprises an eave and is provided with a workpiece through hole. The quenching method comprises: a step for preparing a pressure quenching device capable of switching between a constrained state in which a workpiece is constrained and an unconstrained state in which the workpiece is not constrained; a step for disposing the plurality of heated workpieces in a pressure quenching device in an unconstrained state; a step for constraining the region to be constrained of the workpiece by means of the pressure quenching device by switching the pressure quenching device from the non-constrained state to the constrained state; and a step for cooling the constrained workpiece.

Description

Technical Field

[0001] The present disclosure relates to a quenching method and a constrained quenching device. Background Art

[0002] Since the implementation of heat treatment may cause unexpected deformation of the object, so-called press quenching is known, which achieves both the implementation of heat treatment of the object and the suppression of deformation. Patent Document 1 discloses an apparatus for press quenching.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 5740946 Summary of the invention

[0006] Problems to be solved by the invention

[0007] The press quenching device shown in Patent Document 1 is for one object. That is, the press quenching device shown in Patent Document 1 cannot perform press quenching on multiple objects at one time. On the other hand, a heat treatment process sometimes adopts a so-called batch process in which multiple objects are treated at one time. Therefore, in the technical field of heat treatment, a quenching method and a constrained quenching device that can perform press quenching on multiple quenching objects are desired.

[0008] The present disclosure describes a quenching method and a constrained quenching apparatus capable of performing pressure quenching on a plurality of quenching objects.

[0009] Solutions to Solve Problems

[0010] One aspect of the present disclosure is a quenching method for a quenching object including a disc-shaped portion and provided with a through hole. The quenching method of one aspect comprises: a step of preparing a constrained quenching device capable of switching between a constrained state of the quenching object and a non-constrained state of the quenching object; a step of arranging a plurality of heated quenching objects in the constrained quenching device in the non-constrained state; a step of constraining the constrained portion of the quenching object by the constrained quenching device by switching the constrained quenching device from the non-constrained state to the constrained state; and a step of cooling the constrained quenching object.

[0011] The above-mentioned quenching method restrains a plurality of quenching objects arranged in a predetermined manner, and then cools the restrained quenching objects. Therefore, the plurality of quenching objects can be pressurized and quenched.

[0012] The quenching method may also include a step of immersing the heated multiple quenching objects in a coolant before the restraining step. The restraining step and the cooling step may also be performed while the quenching objects are immersed in the coolant. According to this step, the high-temperature quenching objects can be quickly cooled by the coolant.

[0013] The arranging step of the quenching method may include the steps of arranging a plurality of quenching objects on a positioning member of a constraining quenching device and arranging a plurality of constraining members of the constraining quenching device between the plurality of quenching objects. According to this step, the plurality of quenching objects can be pressurized and quenched.

[0014] In the arrangement step of the quenching method, the plurality of quenching objects may be arranged on the positioning member along the axis of the through hole of the quenching object. According to this step, the plurality of quenching objects can be restrained by a simple operation.

[0015] In the constraint step of the quenching method, the first constraint member may be pressed against the main surface of the disk-shaped portion of the quenching object as the constraint target portion, and the second constraint member may be pressed against the back surface of the disk-shaped portion. According to this step, deformation of the disk-shaped portion of the quenching object can be suppressed.

[0016] The above-mentioned quenching method may also include a step of immersing the quenching object arranged in the restraining quenching device into a coolant after the restraining step. The restraining step may also be implemented in a state where the quenching object is not immersed in the coolant. The first period of the cooling step may also be implemented in a state where the quenching object is not immersed in the coolant. The second period of the cooling step following the first period may also be implemented in a state where the quenching object is immersed in the coolant. According to this step, the time from configuration to restraint can be ensured.

[0017] The restraining step and cooling step of the quenching method can also be carried out without the quenching object being immersed in the coolant. This step can also ensure the time from placement to restraint.

[0018] Another aspect of the present disclosure is a constrained quenching device for a quenching object including a disc-shaped portion and provided with a through hole. As another aspect, the constrained quenching device comprises: a positioning member for maintaining the position and posture of a plurality of quenching objects; a plurality of constraining members capable of contacting the constraining object portion of the quenching object; and a pressing mechanism for pressing the constraining member toward the constraining object portion. The constraining member and the pressing mechanism switch between a constrained state in which the quenching object is constrained and a non-constrained state in which the quenching object is not constrained. With this device, a plurality of quenching objects can also be pressurized and quenched.

[0019] Effects of the Invention

[0020] According to the quenching method and constrained quenching apparatus disclosed in the present invention, a plurality of quenching objects can be pressurized and quenched. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram showing a quenching facility to which the quenching method and the press quenching device of the present disclosure are applied.

[0022] Figure 2 It is a cross-sectional view of the workpiece.

[0023] Figure 3 It is the main view of the workpiece.

[0024] Figure 4 (a) is a graph showing the temperature change of the workpiece. Figure 4 (b) is a diagram showing the state immediately after the workpiece is immersed in the coolant. Figure 4 (c) is a diagram schematically showing the state during the rapid cooling period in which the vapor film is separated from the workpiece. Figure 4 (d) is a diagram schematically showing the state during the slow cooling period in which the workpiece is in contact with the coolant.

[0025] Figure 5 It is a cross-sectional view showing the structure of a press quenching device in an exploded manner.

[0026] Figure 6 It is a cross-sectional view showing a positioning tool of a press quenching device.

[0027] Figure 7 (a) is a cross-sectional view showing the unconstrained state of the press quenching apparatus. Figure 7 (b) is a cross-sectional view showing the restrained state of the press quenching apparatus.

[0028] Figure 8 is a flow chart of the quenching method of the present disclosure.

[0029] Fig. 9 This is a schematic diagram showing the main steps of the quenching method.

[0030] Fig.10 (a) is a diagram showing a state of a process of placing a plurality of workpieces together with a transfer tool into a heating furnace. Fig.10 (b) is a diagram showing a state of a step of placing the positioning tool in the coolant filling the cooling tank.

[0031] Fig.11 This is a diagram showing a state of a process in which a transport tool on which a plurality of workpieces are arranged is taken out of a heating furnace and then moved onto a cooling liquid.

[0032] Fig.12 This is a diagram showing a state of a process of arranging a plurality of workpieces on a positioning tool.

[0033] Fig.13 This is a diagram showing a state where the transport tool is pulled out from the workpiece.

[0034] Fig.14 This is a diagram showing a state of a process of moving a restraining tool onto the coolant.

[0035] Fig.15 This is a diagram showing a state of a process of arranging a constraining tool around a workpiece.

[0036] Fig.16 This is a diagram showing a state of a process of placing a second positioning tool in the coolant filling the cooling tank.

[0037] Fig.17 This is a diagram showing a state of a process of seating a plurality of workpieces on a second positioning tool.

[0038] Fig.18 This is a diagram showing a state where the second transport tool is pulled out from the workpiece.

[0039] Fig.19 This is a diagram showing a state of the process of moving the second restraining tool onto the coolant.

[0040] Fig. 20 It is a diagram showing the state of the process of configuring the pressing unit.

[0041] Fig.21 It is a figure which shows the state which performs the press quenching process.

[0042] Fig. 22 This is a flow chart of the quenching method according to Modification 1.

[0043] Fig.23 This is a flow chart of the quenching method according to Modification Example 2.

[0044] Fig.24 It is a diagram showing a modified example of the positioning tool.

[0045] Fig.25 (a) Fig.25 (b) and Fig.25 (c) is an example of a workpiece that can be quenched by the quenching method and the press quenching apparatus. DETAILED DESCRIPTION

[0046] Hereinafter, the mode for implementing the quenching method and the constrained quenching device of the present disclosure will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and repeated descriptions are omitted.

[0047] Figure 1This is a schematic diagram showing a quenching device using a press quenching device 1 (constrained quenching device). The workpiece 600 is a bearing component. For example, the workpiece 600 is used for a needle roller thrust bearing, a stamped outer ring needle roller bearing, a thin-walled bearing, and a large-diameter bearing. The press quenching device 1 constrains a plurality of workpieces 600 in a coolant 504s.

[0048] A plurality of workpieces 600 are transported by a transport tool 501. The transport tool 501 is connected to a moving mechanism 502. The moving mechanism 502 moves the transport tool 501 from a heating furnace 503 to a cooling tank 504. The quenching facility processes a considerable number of workpieces 600 in batches.

[0049] <Objects to be quenched>

[0050] like Figure 2 and Figure 3 As shown, the workpiece 600 has a disc-shaped flange portion 601 (disc-shaped portion) and a cylindrical lip portion 602. The shape of the workpiece 600 is not limited to Figure 2 and Figure 3 Other shapes of the workpiece 600 are exemplified in the column of modified examples described later.

[0051] The eaves 601 is a thin plate whose thickness is thinner than the outer diameter. After the workpiece 600 is heated to 750°C to 900°C, when the workpiece 600 is immersed in the coolant 504s, the surface of the workpiece 600 in contact with the coolant 504s is cooled rapidly. As a result, heat is sequentially transferred from the inside of the workpiece 600 to the surface of the workpiece 600. Strictly speaking, there is a difference in the cooling state between the surface and the inside of the workpiece 600. However, the thickness of the workpiece 600 illustrated in the present disclosure is thin. Therefore, it can be considered that there is substantially no difference in the cooling method of the surface and the inside of the workpiece 600. The "thin plate" described in the present disclosure refers to a component in which the cooling method of the surface and the inside can be considered to be substantially the same during cooling.

[0052] The eaves 601 has an eaves main surface 601a, an eaves back surface 601b, and an eaves through hole 601h. The eaves main surface 601a is a flat surface that is substantially free of bumps. A lip 602 is provided on the eaves back surface 601b. The lip 602 extends from the eaves back surface 601b along the normal direction of the eaves back surface 601b. The eaves 601 and the lip 602 are formed by stamping a single sheet of material. Therefore, there is no physical boundary line separating the eaves 601 and the lip 602.

[0053] The central axis of the lip 602 is consistent with the central axis of the eave 601. The lip 602 is coaxial with the eave 601. The lip 602 has a lip base end 602a, a lip terminal end 602b and a lip through hole 602h. The lip base end 602a is connected to the back side 601b of the eave. The lip terminal end 602b is a free end. The height of the lip 602 can also be smaller than the outer shape of the lip 602. The lip through hole 602h forms a workpiece through hole 600h together with the eave through hole 601h. The inner diameter of the lip through hole 602h is the same as the inner diameter of the eave through hole 601h.

[0054] The result of quenching can be evaluated, for example, by the warpage of the flange portion 601 and the roundness of the lip portion 602. When the quenching state is non-uniform, the flange portion 601 may warp. When the quenching state is non-uniform, the roundness of the lip portion 602 may decrease.

[0055] <Mechanism of Quenching>

[0056] Reference Figure 4 , the cooling of the workpiece 600 will be described in more detail. In order to produce a desired metal structure such as martensite in the workpiece 600, the cooling rate is important. Specifically, when the cooling rate when the workpiece 600 is immersed in the coolant 504s is slower than the cooling rate as a reference determined based on experimental results, other metal structures such as pearlite will be produced in addition to martensite. Therefore, the cooling rate of the workpiece 600 must not be slower than the cooling rate as a reference.

[0057] Figure 4 (a) is a graph showing the temperature change of the workpiece 600 when the workpiece 600 is immersed in the cooling liquid 504s. Figure 4 In the workpiece 600 shown in (b), the temperature of the lower part (position B1) of the flange portion 601 changes. Curve G4d is the first cooling reference line. When the temperature history when cooling the workpiece 600 exists in the range to the left of the curve G4d, martensite is formed.

[0058] Pay attention to the curve G4a. Immediately after the workpiece 600 is immersed in the coolant 504s, a vapor film V1 is generated on the surface of the workpiece 600 (refer to Figure 4 (b)). The vapor film V1 has a heat insulating effect. Therefore, the vapor film V1 blocks the transfer of heat from the workpiece 600 to the coolant 504s. As a result, the temperature of the workpiece 600 slowly decreases (period T4a: the period during which the vapor film exists). Thereafter, for some reason, the vapor film V1 begins to peel off from the surface of the workpiece 600 (refer to Figure 4(c)). At the moment of starting peeling, the surface of the workpiece 600 is in direct contact with the coolant 504s. The phenomenon that the vapor film V1 leaves the surface of the workpiece 600 can also be called boiling. The vapor film V1 that leaves the workpiece 600 can also be called a bubble V2. With the direct contact between the workpiece 600 and the coolant 504s as an opportunity, the temperature of the workpiece 600 drops sharply (period T4b: rapid cooling period). The period when the temperature of the workpiece 600 drops sharply can also be called a boiling period. After the temperature of the workpiece 600 drops to a specified value, the temperature of the workpiece 600 slowly drops (period T4c: slow cooling period). For example, during the slow cooling period, there is no vapor film V1 on the surface of the workpiece 600. The workpiece 600 is in direct contact with the coolant 504s.

[0059] <Pressure Quenching Equipment>

[0060] The press quenching device 1 is described below. Figure 5 As shown, the press quenching device 1 includes a first restraining unit 2A, a second restraining unit 2B, and a pressing unit 3 (pressing mechanism). The first restraining unit 2A, the second restraining unit 2B, and the pressing unit 3 are used in an integrated manner when restraining the workpiece 600, but are not mechanically connected. For example, when the workpiece 600 is set in the press quenching device 1, the first restraining unit 2A, the second restraining unit 2B, and the pressing unit 3 are in a disassembled state so as to be independent components.

[0061] The first constraint unit 2A is described. The structure and operation of the second constraint unit 2B are the same as those of the first constraint unit 2A. Therefore, the first constraint unit 2A is described in detail, and the detailed description of the second constraint unit 2B is omitted. When there is no need to distinguish between the first constraint unit 2A and the second constraint unit 2B, they are simply referred to as "constraint unit 2".

[0062] The constraint unit 2 suppresses deformation of the workpiece 600. The constraint unit 2 suppresses the occurrence of unexpected deformation of the workpiece 600 that may occur during quenching. Thus, in the present disclosure, the action for suppressing the occurrence of unexpected deformation of the workpiece 600 is referred to as "constraint". As described later, a function for merely maintaining the position of the workpiece 600 is not included in "constraint".

[0063] The restraining unit 2 has a positioning tool 21 (positioning member) and a restraining tool 22 .

[0064] The positioning tool 21 determines the position of the workpiece 600. Specifically, the positioning tool 21 holds a plurality of workpieces 600 at predetermined intervals. The positioning tool 21 has a function of holding the position of the workpiece 600. However, the positioning tool 21 does not have a function of restricting deformation of the workpiece 600. The positioning tool 21 is, for example, a rectangular plate member in plan view.

[0065] like Figure 6 As shown, the positioning tool 21 has a workpiece placement surface 211 on which the workpiece 600 is placed. A plurality of positioning slits 212 are provided on the workpiece placement surface 211. The placement interval of the positioning slits 212 is the placement interval of the workpiece 600. One workpiece 600 is inserted into one positioning slit 212. The flange portion 601 of the workpiece 600 is inserted into the positioning slit 212. The slit width 212t and the depth 212d of the positioning slit 212 are sufficient as long as the inserted workpiece 600 does not fall.

[0066] Again Figure 5 As shown, the restraining tool 22 restrains the workpiece 600. The restraining tool 22 has a function of suppressing deformation of the workpiece 600. The restraining tool 22 includes a plurality of pressurizing blocks 221 (a plurality of restraining members), a block coupling portion 222, and a plurality of springs 223.

[0067] The plurality of pressure blocks 221 are connected to the block connection portion 222. The plurality of pressure blocks 221 are arranged at intervals from each other along a predetermined axis (X axis). The X axis is aligned with the direction of the central axis A of the workpiece through hole 600h. Each of the plurality of pressure blocks 221 can reciprocate relative to the block connection portion 222 along the X axis.

[0068] like Figure 7 (a) and Figure 7 As shown in (b), the pressurizing block 221 has a block main surface 221s, a block back surface 221b, a block connecting surface 221c, and a block free surface 221f.

[0069] The block main surface 221s is in contact with the workpiece main surface of the workpiece 600. The block main surface 221s has a shape that imitates the workpiece main surface. In the present disclosure, the workpiece main surface is a flat eaves main surface 601a. ​​Therefore, the block main surface 221s is also a flat surface. The block back surface 221b is in contact with the workpiece back surface of the workpiece 600. The block back surface 221b has a shape that imitates the back surface of the workpiece. In the present disclosure, the workpiece back surface includes a flat eaves back surface 601b and a lip 602 protruding from the eaves back surface 601b. Therefore, the block back surface 221b includes a flat surface portion 221p in contact with the eaves back surface 601b and a hole portion 221h that receives the lip 602. The shapes of the block main surface 221s and the block back surface 221b can be appropriately changed according to the shape of the workpiece 600.

[0070] The block connection surface 221c is connected to the block connection portion 222. The block free surface 221f is a portion in contact with the positioning tool 21. The block free surface 221f is not fixed to the positioning tool 21. The restraint tool 22 is not fixed to the positioning tool 21.

[0071] One or more springs 223 are arranged between adjacent pressure blocks 221. Figure 5 and Figure 7, a structure in which two springs 223 are arranged between mutually adjacent pressure blocks 221 is illustrated. However, the number of springs 223 is not limited to two. The first end of the spring 223 is inserted into the spring hole 221e provided on the block main surface 221s of the pressure block 221. The second end of the spring 223 is inserted into the spring hole 221e provided on the block back surface 221b of the pressure block 221.

[0072] The natural length of the spring 223 defines the interval between the adjacent pressure blocks 221. The natural length of the spring 223 is at least longer than the width of the workpiece 600 disposed on the positioning tool 21. Specifically, the natural length of the spring 223 is longer than the height of the lip 602 of the workpiece 600.

[0073] The spring 223 can be contracted to a length shorter than the distance from the bottom surface of the spring hole 221e of the first pressurizing block 221 to the bottom surface of the spring hole 221e of the second pressurizing block 221 adjacent to the first pressurizing block 221. The pressurizing block 221 can contact the adjacent pressurizing block 221.

[0074] The spring 223 is a compression spring. The spring 223 contracts due to the force applied to the constraint unit 2 by the pressing unit 3. When the force applied to the constraint unit 2 by the pressing unit 3 is released, the spring 223 returns to its natural length by the restoring force. Figure 7 (b) The constraint state shown is Figure 7 (a) shows the unconstrained state switching.

[0075] Again Figure 5 As shown, the pressing unit 3 includes a first pressing block pair 31A, a second pressing block pair 31B, a first pressing plate 32 , and a second pressing plate 33 .

[0076] The first pressing block pair 31A corresponds to the first constraint unit 2A. The first pressing block pair 31A has two pressing blocks 311 and 312. The pressing block 311 presses the pressure block 221 arranged at the rightmost end of the first constraint unit 2A. The pressing block 311 has a pressing surface 311s pressed against the pressing block 221. The pressing surface 311s is not fixed relative to the pressure block 221. The surface opposite to the pressing surface 311s is fixed to the first pressing plate 32.

[0077] The pressing block 312 presses the leftmost pressing block 221 of the first restraining unit 2A. The pressing block 312 also has a pressing surface 312s pressed against the pressing block 221. The pressing surface 312s is also not fixed to the pressing block 221. The surface opposite to the pressing surface 312s is fixed to the second pressing plate 33.

[0078] The second pressing block pair 31B corresponds to the second restraining unit 2B. The specific structure of the second pressing block pair 31B is the same as that of the first pressing block pair 31A, so detailed description is omitted.

[0079] Two pressing blocks 311 are mounted on the first pressing plate 32. Two pressing blocks 312 are mounted on the second pressing plate 33. The first pressing plate 32 and the second pressing plate 33 are respectively subjected to the force of the actuator 4 driven by oil pressure or air pressure. The first pressing plate 32 and the second pressing plate 33 transmit the force received from the actuator 4 to the pressing blocks 311 and 312.

[0080] The non-constrained state and the constrained state implemented by the constraint unit 2 are described. The constraint unit 2 can switch between the non-constrained state and the constrained state. Figure 7 (a) indicates a non-constrained state. In the non-constrained state, the constraint unit 2 receives no force from the pressing unit 3. Therefore, the spring 223 has a natural length 223L. The interval between the adjacent pressure blocks 221 is determined by the natural length 223L of the spring 223. The interval 221L between the adjacent pressure blocks 221 is longer than the height 600L of the workpiece 600.

[0081] Figure 7 (b) indicates a constrained state. When in the constrained state, the constraining unit 2 is subjected to a force generated by the actuator 4. The block main surface 221s is pressed against the eaves main surface 601a. ​​The flat surface 221p of the block back surface 221b is pressed against the eaves back surface 601b. Since the eaves 601 receives forces from these two surfaces, it is in a constrained state. In the constrained state, deformation such as increasing the thickness of the eaves 601 is not allowed. In the constrained state, deformation such as tilting in the thickness direction (X-axis direction) of the eaves 601 is also not allowed. The outer peripheral surface 602s of the lip 602 contacts the inner peripheral surface 221q of the hole portion 221h on the back surface 221b of the block. In this state, expansion deformation of the lip 602 is suppressed. The hole portion 221h on the back surface 221b of the block constrains the lip 602 in such a way that the outer diameter of the lip 602 is not greater than a specified value.

[0082] Therefore, in the restrained state, the deformation of the flange portion 601 is restricted. As a result, the flatness of the flange portion 601 is suppressed from being deteriorated. In the restrained state, the deformation of the lip portion 602 is restricted. As a result, the roundness of the lip portion 602 is suppressed from being deteriorated.

[0083] The press hardening device 1 can restrain a plurality of workpieces 600 by a single pressing operation. The press hardening device 1 can perform so-called batch processing in which a plurality of workpieces 600 are processed collectively.

[0084] <Quenching method>

[0085] Reference Figure 8 The flowchart shown and Figures 9 to 21 , a quenching method using the press quenching apparatus 1 will be described.

[0086] like Fig. 9 As shown, the quenching method includes a process of heating the workpiece 600 using the heating furnace 503 (step S13), a process of transporting the workpiece 600 (step S22), a process of cooling the workpiece 600 using the cooling tank 504 (steps S23 to S31), and a process of preparing the next workpiece 600.

[0087] The workpiece 600 is arranged on the first to Nth conveying tools 501 (step S11). N is a plurality of integers. The conveying tool 501 is a round rod. The diameter of the conveying tool 501 is substantially the same as or slightly smaller than the inner diameter of the workpiece through hole 600h. A step is provided on the outer peripheral surface of the conveying tool 501. The position of the workpiece 600 is determined by the step. Determining the position of the workpiece 600 means determining the interval between mutually adjacent workpieces 600. The conveying tool 501 can be made of, for example, steel having a carbon content of about 0.7% or more and about 1.2% or less.

[0088] Next, the plurality of workpieces 600 are placed in the heating furnace 503 together with the first to Nth transport tools 501 (see steps S12, Fig.10 (a)). Next, the plurality of workpieces 600 are heated together with the first to Nth transport tools 501 (see step S13, Fig.10 (a)). The heating furnace 503 can set the interior of the heating chamber to a vacuum. Therefore, the workpiece 600 is placed in a vacuum environment at a predetermined temperature for a predetermined time. As an example, the workpiece 600 is heated to a temperature between 750 degrees Celsius and 900 degrees Celsius. The temperature between 750 degrees Celsius and 900 degrees Celsius is maintained for about 5 to 30 minutes.

[0089] Next, the first positioning tool 21 is placed in the cooling liquid 504s filling the cooling tank 504 (see step S21, Fig.10 (b) Then, the first transport tool 501 on which the plurality of workpieces 600 are arranged is taken out from the heating furnace 503. Then, the first transport tool 501 is moved onto the cooling liquid 504s (see step S22, Fig.11 ). Next, the plurality of workpieces 600 together with the first conveying tool 501 are sunk into the cooling liquid 504s (step S23). When the workpieces 600 in a high temperature state contact the cooling liquid 504s, a vapor film V1 is generated on the surface of the workpieces 600. Next, by further sinking the first conveying tool 501 on which the plurality of workpieces 600 are arranged, the plurality of workpieces 600 are arranged on the first positioning tool 21 (refer to steps S24, Fig.12 ). Each of the plurality of workpieces 600 is inserted into the plurality of positioning slits 212. The state in which the plurality of workpieces 600 are arranged on the first positioning tool 21 is referred to as "seating".

[0090] Next, the first transport tool 501 is removed from the workpiece 600 (see step S25, Fig.13 There is no particular limitation on the mechanism for pulling out the first conveying tool 501. Since the plurality of workpieces 600 are seated on the first positioning tool 21, the first conveying tool 501 remains upright even when it is pulled out. After step S25 is completed, a vapor film V1 also exists on the surface of the workpiece 600.

[0091] Next, the first restraining tool 22 is moved onto the cooling liquid 504s (see step S26, Fig.14 ). The mechanism 505 for moving the first restraining tool 22 (see Figure 1 After step S26 is completed, a vapor film V1 also exists on the surface of the workpiece 600 .

[0092] Next, the first restraining tool 22 is arranged around the workpiece 600 (see step S27, Fig.15 ). Specifically, the first restraining tool 22 is sunk into the coolant 504s until the block free surface 221f of the first restraining tool 22 contacts the workpiece placement surface 211 of the first positioning tool 21. As a result, a state is achieved where one workpiece 600 is placed between mutually adjacent pressurizing blocks 221. After step S27 is completed, the vapor film V1 also exists on the surface of the workpiece 600.

[0093] The above steps S21 to S27 are repeated a number of times corresponding to the number of the transport tools 501. For example, the second positioning tool 21 is placed in the cooling liquid 504s filled with the cooling tank 504 (see steps S21, Fig.16 ). Next, the second conveying tool 501 with the plurality of workpieces 600 is taken out from the heating furnace 503. Next, the second conveying tool 501 is moved onto the cooling liquid 504s (step S22). Next, the plurality of workpieces 600 are seated on the second positioning tool 21 by sinking the plurality of workpieces 600 together with the second conveying tool 501 into the cooling liquid 504s (refer to steps S24, Fig.17 Next, the second transport tool 501 is removed from the workpiece 600 (see step S25, Fig.18 Then, the second restraining tool 22 is moved to the top of the cooling liquid 504s (step S26, see Fig.19 ). Then, the second constraining tool 22 is arranged around the workpiece 600 (step S27).

[0094] It is also possible to determine whether all the workpieces 600 have been arranged each time steps S21 to S27 are repeated (step S28). If there are still workpieces 600 left in the heating furnace 503 (step S28: No), steps S21 to S27 are performed again. If there are no workpieces 600 left in the heating furnace 503 (step S28: Yes), it can be determined that all the workpieces 600 have been arranged.

[0095] Next, the pressing unit 3 is configured (see step S31, Fig. 20 ). Next, press quenching is performed (refer to step S32, Fig.21 ). The press quenching device 1 is switched from an unconstrained state to a constrained state. Specifically, the pressing unit 3 applies force to the first constraining unit 2A and the second constraining unit 2B. The interval between the adjacent press blocks 221 gradually narrows. During this period, the lip 602 is inserted into the hole 221h. In this state, the lip 602 is supported by the hole 221h. Therefore, it is not necessary to support the lower end of the workpiece 600 with the positioning tool 21. As a result, the positioning tool 21 can be removed from the lower end of the eaves 601. The workpiece 600 is in a state of being unconstrained relative to the direction of pressing. Therefore, as the interval between the press blocks 221 narrows, the interval between the workpieces 600 also narrows. The block main surface 221s is in contact with the eaves main surface 601a. ​​The block back surface 221b is in contact with the eaves back surface 601b. More specifically, the block main surface 221s and the block back surface 221b are pressed against the eaves main surface 601a and the eaves back surface 601b by a force that can resist the force accompanying the deformation of the eaves 601 (see Figure 7 (b)).

[0096] In the unconstrained state, there is a vapor film V1 on the surface of the workpiece 600 (refer to Fig. 20 ). In the restrained state, the pressure block 221 is in direct contact with the workpiece 600. Figure 4 As shown in the curve G4a of FIG. 1 , the unconstrained state is the first period (T4a) during which the temperature slowly decreases. During the period of switching from the unconstrained state to the constrained state, the vapor film V1 separates from the surface of the workpiece 600. In other words, the rapid cooling of the workpiece 600 begins. Figure 4 As shown in the curve G4a of , the restrained state is the second period (T4b) in which the temperature drops sharply. In the present disclosure, the time from when the workpiece 600 is immersed in the coolant 504s to when the vapor film V1 starts to be peeled off from the surface of the workpiece 600 is not considered as the quenching period for quenching. In the present disclosure, the time when the peeling of the vapor film V1 starts is regarded as the start of rapid cooling (the start of quenching treatment). The heat of the workpiece 600 has the following two ways of moving: a way of moving to the coolant 504s through direct contact between the workpiece 600 and the coolant 504s; and a way of moving to the pressurizing block 221 through direct contact between the workpiece 600 and the pressurizing block 221.

[0097] The vapor film V1 is an unstable existence. Therefore, the vapor film V1 sometimes has nothing to do with the approach of the pressure block 221, but detaches with the passage of time. When the vapor film V1 detaches, rapid cooling begins. The pressurized quenching device 1 suppresses the deformation of the workpiece 600 generated during rapid cooling. Therefore, the switch from the unconstrained state to the constrained state must be completed before the rapid cooling begins. For example, the period from when the workpiece 600 is immersed in the coolant 504s to when the vapor film V1 begins to peel off naturally is about several seconds (about 3 seconds to 7 seconds). Therefore, the processes from step S21 to step S32 are all completed within these few seconds.

[0098] Next, unloading is performed (step S33). The press quenching device 1 is switched from the constrained state to the unconstrained state. Next, the workpiece 600 and the positioning tool 21 are sequentially taken out from the coolant 504s (step S34). The workpiece 600 is taken out from the positioning tool 21 (step S35). After the above steps, the quenching of multiple workpieces 600 is completed.

[0099] The effects of the press quenching device 1 and the quenching method of the present disclosure will be described.

[0100] The quenching method disclosed in the present invention is used for a workpiece 600 including a flange portion 601 and provided with a workpiece through hole 600h. The quenching method comprises: a step of preparing a press quenching device 1 capable of switching between a constrained state in which the workpiece 600 is constrained and a non-constrained state in which the workpiece 600 is not constrained; a step of arranging a plurality of heated workpieces 600 in the press quenching device 1 in a non-constrained state; a step of constraining a constrained portion of the workpiece 600 using the press quenching device 1 by switching the press quenching device 1 from a non-constrained state to a constrained state; and a step of cooling the constrained workpiece 600.

[0101] The quenching method disclosed herein starts cooling the workpiece 600 in the constrained state after constraining a plurality of workpieces 600 arranged in a prescribed manner. "The start of cooling" refers to the start of peeling of the vapor film V1. Therefore, it is possible to perform pressure quenching on a plurality of workpieces 600. Since the workpiece 600 obtained by pressure quenching suppresses deformation caused by heat treatment, it is possible to suppress the production of defective products that do not meet the conditions imposed on shape accuracy. The quenching method disclosed herein can suppress deformation of the workpiece 600 caused by heat treatment, and thus can suppress the production of defective products. It is possible to improve the yield rate when heat treating a plurality of workpieces 600 at a time.

[0102] The quenching method further includes a step of immersing a plurality of workpieces 600 in the coolant 504s before the restraining step. The restraining step and the cooling step are performed while the workpieces 600 are immersed in the coolant 504s. According to this step, the high-temperature workpieces 600 can be quickly cooled by the coolant 504s.

[0103] The arranging step includes arranging the plurality of workpieces 600 on the positioning jig 21 of the press hardening apparatus 1 and arranging the plurality of restraining jigs 22 of the press hardening apparatus 1 between the plurality of workpieces 600. According to this step, the plurality of workpieces 600 can be press hardened.

[0104] In the arrangement step, the plurality of workpieces 600 are arranged on the positioning jig 21 along the axis of the through-hole of the workpiece 600. According to this step, the plurality of workpieces 600 can be restrained by a simple operation.

[0105] In the restraining process, the first restraining tool 22 is pressed against the flange main surface 601a of the flange 601 of the workpiece 600 as the restraining target portion, and the second restraining tool 22 is pressed against the flange back surface 601b of the flange 601. According to this process, deformation of the flange 601 included in the workpiece 600 can be suppressed.

[0106] The press quenching device 1 is used for a workpiece 600 including a flange portion 601 and provided with a workpiece through hole 600h. The press quenching device 1 includes: a positioning tool 21 for maintaining the position and posture of a plurality of workpieces 600; a plurality of press blocks 221 in contact with the constrained portion of the workpiece 600; and a pressing unit 3 for pressing the press blocks 221 toward the constrained portion. The press blocks 221 and the pressing unit 3 switch between a constrained state in which the workpiece 600 is constrained and a non-constrained state in which the workpiece 600 is not constrained. With this device, a plurality of workpieces 600 can also be press quenched.

[0107] The quenching method and constrained quenching apparatus disclosed herein are not limited to the above-described embodiments.

[0108] <Modification 1>

[0109] The quenching method disclosed herein is to rapidly cool the workpiece 600 in the coolant 504s. The quenching process only needs to cool the workpiece 600 at a predetermined cooling rate, so it is not necessarily necessary to immerse the workpiece in the coolant 504s. For example, if the pressure block 221 has a sufficiently large heat capacity, quenching can be performed without immersing the workpiece in the coolant 504s.

[0110] Fig. 22A flowchart showing a quenching method according to Modification 1. In the quenching method according to Modification 1, quenching is performed without using the coolant 504s. The press quenching apparatus 1 used in the quenching method according to Modification 1 is the same as the press quenching apparatus 1 used in the quenching method of the present disclosure.

[0111] The heat treatment is performed on the plurality of workpieces 600. Steps S11, S12, and S13 for the heat treatment in Modification 1 are the same as Steps S11, S12, and S13 of the present disclosure.

[0112] Next, the nth positioning tool 21 is configured (step S21A). In the quenching method of the present disclosure, the nth positioning tool 21 is configured in the coolant 504s. In the quenching method of variant example 1, the nth positioning tool 21 is configured in the atmosphere. The nth positioning tool 21 does not sink into the coolant 504s. Next, a plurality of workpieces 600 are configured on the nth positioning tool 21 (step S24A). The workpieces 600 are configured on the nth positioning tool 21 in the atmosphere. The quenching method of variant example 1 does not perform the step of moving the plurality of workpieces 600 onto the coolant 504s (step S22) and the step of sinking the plurality of workpieces 600 into the coolant 504s (step S23) performed in the embodiment.

[0113] Next, the n-th conveying tool 501 is pulled out from the plurality of workpieces 600 (step S25A). Next, the n-th restraining tool 22 is moved and arranged around the workpiece 600 (steps S26A, S27A). After the arrangement of all the workpieces 600 is completed (step S28: Yes), the pressing unit 3 is arranged (step S31A). Press quenching is performed (step S32A). After that, after unloading (step S33A), the workpiece 600 is taken out from the positioning tool 21 (step S35A).

[0114] The process of constraining (steps S21A to S28) and the process of cooling (step S32A) of the quenching method of Modification 1 are performed without the workpiece 600 being immersed in the coolant 504s. According to this process, the time from configuration to constraint can be ensured. The quenching method of Modification 1 can also perform pressure quenching on multiple workpieces 600 at a time.

[0115] <Modification 2>

[0116] The quenching method of Modification 1 is to rapidly cool the workpiece 600 in the air. For example, the rapid cooling of the workpiece 600 may be performed in the air and in the coolant 504s. Fig.23 A flowchart showing a quenching method according to Modification 2. In the quenching method according to Modification 2, first, the unconstrained state is switched to the constrained state in the atmosphere. Then, after a predetermined time has passed, the pressurized quenching apparatus 1 in the constrained state is immersed in the coolant 504s.

[0117] like Fig.23 As shown, steps S11, S12, and S13 for heat treatment are performed. Next, steps S21B to S27B are performed to prepare for press quenching in the atmosphere. Steps S21B to S27B are the same as steps S21A to S27A of the first modification.

[0118] Next, after the press unit 3 is configured (step S31B), press quenching is performed (step S32B1). The press quenching device 1 is switched from the unconstrained state to the constrained state. After a predetermined time has passed since the constrained state, the press quenching device 1 in the constrained state is sunk into the coolant 504s (step S32B2). Next, after unloading (step S33B), the workpiece 600 is taken out of the coolant 504s (step S34B). The workpiece 600 is taken out of the press quenching device 1 (step S35B).

[0119] The quenching method of variant example 2 further includes a step (step S32B2) of immersing the workpiece 600 arranged in the press quenching device 1 in the coolant 504s after the step of performing the constraint (step S32B1). The step of performing the constraint (step S32B1) is implemented in a state where the workpiece 600 is not immersed in the coolant 504s. The first period of the cooling process (step S32B1) is implemented in a state where the workpiece 600 is not immersed in the coolant 504s. The second period of the cooling process (step S32B2) following the first period is implemented in a state where the workpiece 600 is immersed in the coolant 504s. According to this process, the time from configuration to constraint can be ensured. In addition, by the quenching method of variant example 2, multiple workpieces 600 can also be press quenched at one time.

[0120] According to the quenching method of Modification 2, even when the heat capacity of the press block 221 is not large enough, the workpiece 600 can be sufficiently cooled by sinking into the coolant 504s (step S32B). Even with a small press block 221 having a relatively small heat capacity, a plurality of workpieces 600 can be press-quenched at one time.

[0121] <Modification of positioning tool>

[0122] Positioning tools can also be used Fig.24 The structure shown. Fig.24 The prism member 21A is provided with a plurality of positioning slits which are arranged in a spaced relationship from each other along the longitudinal direction. With such a structure, a plurality of workpieces 600 can be held.

[0123] <Examples of quenching objects>

[0124] Fig.25The workpiece 600A shown in (a) includes a flange portion 601A and a lip portion 602A. The flange portion 601A is formed with a flange portion through hole 601h. The lip portion 602A stands up from the outer peripheral edge of the flange portion 601A. The lip portion 602A extends linearly from the flange portion 601A. The lip portion 602A does not include a portion bent between a portion connected to the flange portion 601A and a terminal end.

[0125] Fig.25 The workpiece 600B shown in (b) includes a flange portion 601B and a lip portion 602B. The flange portion 601B is formed with a flange portion through hole 601h. The lip portion 602B stands up from the outer peripheral edge of the flange portion 601B. The lip portion 602B includes a curling portion 603 between the portion connected to the flange portion 601B and the end. The lip portion 602B is bent inwardly starting from the curling portion 603. The inner diameter of the end portion of the lip portion 602B is smaller than the outer diameter of the flange portion 601B.

[0126] Fig.25 The workpiece 600C shown in (c) has a flange 601C, an inner lip 604C, and an outer lip 602C. The inner lip 604C forms a workpiece through hole 600h together with a flange through hole 601h provided on the flange 601C. The outer lip 602C rises from the outer peripheral edge of the flange 601C. The direction in which the outer lip 602C rises is the same as the direction in which the inner lip 604C rises. The height of the outer lip 602C may be higher than that of the inner lip 604C.

[0127] Description of Reference Numerals

[0128] 1... Pressing quenching device (constrained quenching device), 2, 2A, 2B... Constraint unit, 21... Positioning tool (positioning member), 22... Constraint tool (constraint member), 211... Workpiece placement surface, 212... Positioning slit, 212t... Slit width, 221... Pressing block, 221b... Block back surface, 221c... Block connecting surface, 221e... Spring hole, 221f... Block free surface, 221h... Hole portion, 221L... Interval, 221p... Flat surface, 221q... Inner peripheral surface, 221s... Block main surface, 222... Block connecting portion, 223... Spring, 223L... Natural length, 3... Pressing unit (pressing mechanism), 31A, 31B... Pressing block pair, 32, 33... Pressing plate, 311, 312... Pressing block, 311s, 31 2s…pressing surface, 4…actuator, 501…conveying tool, 502…moving mechanism, 503…heating furnace, 504…cooling tank, 504s…cooling liquid, 600, 600A, 600B, 600C…workpiece (quenching object), 600h…workpiece through-hole, 601, 601A, 601B, 601C…eaves (disk-shaped portion), 601a…eaves main surface, 601b…eaves back surface, 601h…eaves through-hole, 602, 602A, 602B…lip, 602a…lip base end, 602b…lip tip, 602C…outer lip, 602h…lip through-hole, 602s…outer peripheral surface, 603…curling portion, 604C…inner lip, A…center axis, V1…vapor film, V2…bubble.

Claims

1. A quenching method for a quenching object including a disc-shaped portion and provided with a through hole, The quenching method has the following characteristics: The step of preparing a constrained quenching device capable of switching between a constrained state in which the quenching object is constrained and a non-constrained state in which the quenching object is not constrained; The step of placing the plurality of heated quenching objects in a constrained quenching device in an unconstrained state; The step of constraining a constrained portion of the object to be quenched by the constrained quenching device by switching the constrained quenching device from the unconstrained state to the constrained state; and A step of cooling the constrained quenching object.

2. The quenching method according to claim 1, Prior to the step of restraining, there is also a step of immersing the heated plurality of quenching objects in a cooling liquid. The restraining step and the cooling step are performed with the quenching object immersed in the coolant.

3. The quenching method according to claim 2, The configuration process includes: a step of placing a plurality of the quenching objects on a positioning member of the constrained quenching device; as well as and a step of arranging a plurality of restraining members of the restraining quenching device between the plurality of quenching objects, respectively. 4 . The quenching method according to claim 3 , wherein in the step of arranging, a plurality of the objects to be quenched are arranged on the positioning member along the axis of the through hole of the objects to be quenched.

5. The quenching method according to claim 4, wherein in the constraining step, the first constraining member is pressed against the main surface of the disk-shaped portion of the quenching object as the constrained portion, and the second constraining member is pressed against the back surface of the disk-shaped portion.

6. The quenching method according to claim 1, After the restraining step, there is further a step of immersing the quenching object arranged in the restraining quenching device in a cooling liquid. The restraining step is performed in a state where the quenching object is not immersed in the coolant. The first period of the cooling step is carried out in a state where the quenching object is not immersed in the coolant. A second period of the cooling step subsequent to the first period is performed in a state where the quenching object is immersed in the coolant. 7 . The quenching method according to claim 1 , wherein the restraining step and the cooling step are performed in a state where the quenching object is not immersed in a coolant.

8. A constrained quenching device for a quenching object including a disc-shaped portion and provided with a through hole, The constrained quenching device comprises: A positioning member for maintaining the positions and postures of the plurality of quenching objects; a plurality of restraining members capable of contacting restraining target portions of the quenching target object; and A pressing mechanism presses the restraining member toward the restraining object portion, The restraining member and the pressing mechanism switch between a restraining state in which the quenching object is restrained and a non-restraining state in which the quenching object is not restrained.

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