Quenching apparatus

Abstract

A quenching apparatus comprises a casing, a motor that generates rotational power, a carrier that is disposed in the casing and carries a member to be treated, a drive mechanism that is disposed in the casing and transmits the rotational power to the carrier to change a position assumed by the carrier in a vertical direction, a suspension chain that interconnects the drive mechanism and the carrier, a sensing member connected to the carrier and having a sensing unit, and a sensor that senses the position assumed by the carrier based on a position of the sensing unit. The sensor continuously senses the position assumed by the carrier while the carrier positionally varies in the vertical direction.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This nonprovisional application is based on Japanese Patent Application No. 2025-013986 filed on Jan. 30, 2025 with the Japan Patent Office, the entire contents of which are hereby incorporated by reference.BACKGROUND OF THE INVENTIONField of the Invention

[0002] The present disclosure relates to a quenching apparatus.Description of the Background Art

[0003] WO2020 / 203226 discloses a quenching apparatus. The quenching apparatus described in WO2020 / 203226 comprises a cooling bath, a support base, and a moving device. The cooling bath has a coolant reserved therein. The support base carries a member to be treated. The moving device vertically moves the member to be treated.SUMMARY OF THE INVENTION

[0004] The quenching apparatus described in WO2020 / 203226 has room for improvement in sensing a position assumed by the support base in the vertical direction. The present disclosure provides a quenching apparatus capable of sensing a position assumed by a carrier in the vertical direction while a member to be treated is carried on the carrier and thus quenched in a hermetic condition.

[0005] The presently disclosed quenching apparatus comprises a casing, a motor that generates rotational power, a carrier that is disposed in the casing and carries a member to be treated, a drive mechanism that is disposed in the casing and transmits the rotational power to the carrier to change a position assumed by the carrier in a vertical direction, a suspension chain that interconnects the drive mechanism and the carrier, a sensing member connected to the carrier and having a sensing unit, and a sensor that senses the position assumed by the carrier based on a position of the sensing unit. The sensor continuously senses the position assumed by the carrier while the carrier positionally varies in the vertical direction.

[0006] The foregoing and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 schematically shows a quenching apparatus 100.

[0008] FIG. 2 is an enlarged view of a portion II indicated in FIG. 1.

[0009] FIG. 3 is a flowchart of a process of a quenching method using quenching apparatus 100.

[0010] FIG. 4 schematically shows quenching apparatus 100 according to a variation.

[0011] FIG. 5 is a flowchart of a process of a quenching method using quenching apparatus 100 according to a variation.DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Embodiments of the present disclosure will more specifically be described with reference to the drawings. In the following figures, identical or equivalent components are identically denoted and will not be described repeatedly. A quenching apparatus according to an embodiment will be referred to as a quenching apparatus 100.Configuration of Quenching Apparatus 100

[0013] Hereinafter, a configuration of quenching apparatus 100 will be described.

[0014] As shown in FIG. 1, quenching apparatus 100 comprises a casing 10, a motor 20, a carrier 30, and a drive mechanism 40. Quenching apparatus 100 may further comprise a suspension chain 50, a sensing member 60, and a sensor 70.

[0015] Casing 10 includes a cooling bath 11 and a waiting chamber 12. Cooling bath 11 reserves a coolant CL therein. Coolant CL is not particularly limited. Coolant CL is, for example, water, an aqueous solution of a polymer, oil, or the like. Waiting chamber 12 is located above cooling bath 11 in the vertical direction. An upward / downward direction in FIG. 1 corresponds to the vertical direction. Waiting chamber 12 has an internal space connected to an internal space of cooling bath 11 in the vertical direction.

[0016] Motor 20 is, for example, a servo motor. Note, however, that motor 20 is not limited to a servo motor. For example, motor 20 is connected to a servo amplifier (not shown), and the servo amplifier is connected to a controller (not shown). The controller generates a control signal for how many times motor 20 rotates and a speed at which the motor rotates, and the controller outputs the control signal to the servo amplifier. In response to the control signal, the servo amplifier outputs a drive signal for motor 20, and in response to the drive signal, motor 20 rotates and thus generates rotational power.

[0017] Carrier 30 carries a member to be treated W. The member to be treated W is made for example of steel. Although not shown, waiting chamber 12 is provided with an openable and closable first opening that allows waiting chamber 12 to have its internal space in communication with outside. Waiting chamber 12 is also provided with another openable and closable, second opening in communication with a heating chamber (not shown) used for heating the member to be treated W. Carrier 30 is disposed in the internal space of waiting chamber 12 at a stage before the member to be treated W is cooled. The member to be treated W is moved through the opening and thus carried on carrier 30 in a heated state. Casing 10 conserves heat to prevent the member to be treated W from having a rapid decrease in temperature when the member to be treated is ejected from the heating chamber. Furthermore, while immersing in coolant CL the member to be treated W ejected from the heating chamber generates vapor, casing 10 suppresses diffusion of the vapor to the surroundings. Furthermore, casing 10 isolates the member to be treated W that is ejected from the heating chamber from the atmosphere to prevent oxidation of the member to be treated W.

[0018] Drive mechanism 40 is disposed in casing 10. Drive mechanism 40 for example has a wheel 41. Suspension chain 50 has one end connected to wheel 41 and has the other end connected to carrier 30. Suspension chain 50 is wound on wheel 41. Motor 20 is connected to wheel 41. Wheel 41 is rotated as the rotational power of motor 20 is transmitted to wheel 41. When wheel 41 rotates in the forward direction, suspension chain 50 is fed from wheel 41, and carrier 30 moves downward in the vertical direction. In contrast, when wheel 41 is rotated in the reverse direction, suspension chain 50 is wound on wheel 41, and carrier 30 moves upward in the vertical direction. In this manner, the position assumed by carrier 30 in the vertical direction will be changed by the rotational power of motor 20.

[0019] Sensing member 60 extends in the vertical direction. As shown in FIG. 2, casing 10 has a through hole 12a. Through hole 12a is for example formed through an upper wall of waiting chamber 12 and penetrates the upper wall of waiting chamber 12 in the vertical direction. Sensing member 60 is passed through through hole 12a. A gap between an internal wall surface of through hole 12a and sensing member 60 is sealed by a seal member 12b. A groove 12c is formed in the internal wall surface of through hole 12a, and seal member 12b is fitted in groove 12c. Seal member 12b is, for example, an O-ring.

[0020] Sensing member 60 has one end (a lower end) connected to carrier 30. Sensing member 60 has a sensing unit 61. Sensing unit 61 is located outside casing 10. Sensing member 60 is, for example, thinner than suspension chain 50. That is, sensing member 60 has a width (if sensing member 60 is in the form of a rod, it has a diameter) smaller than a minimum width of suspension chain 50. From a different point of view, a weight that sensing member 60 can support is smaller than a weight that suspension chain 50 can support.

[0021] Sensor 70 continuously senses carrier 30 in position and speed in the vertical direction while carrier 30 moves. Sensor 70 for example includes a distance sensor 72. Distance sensor 72 is attached to an exterior of casing 10. More specifically, distance sensor 72 is attached on the upper wall of waiting chamber 12. Distance sensor 72 is spaced from and thus faces sensing unit 61. Distance sensor 72 is, for example, an optical distance sensor. Distance sensor 72 has a light emitting unit to emit laser light toward sensing unit 61. Distance sensor 72 has a light receiving unit to receive laser light reflected at sensing unit 61. Based on a period of time elapsing between the emission of the laser light and the reflection of the laser light, distance sensor 72 senses a position assumed by sensing unit 61 in the vertical direction, that is, a position assumed by carrier 30 in the vertical direction. A distance between sensing unit 61 and distance sensor 72 in the vertical direction varies with time. Based on the variation with time of the distance between sensing unit 61 and distance sensor 72 in the vertical direction, distance sensor 72 continuously senses a speed at which carrier 30 moves in the vertical direction.

[0022] Sensor 70 may further include an encoder 71. Encoder 71 is attached to motor 20. Encoder 71 is, for example, an optical encoder, a magnetic encoder, or an electromagnetic induction type encoder. Encoder 71 senses how many times motor 20 rotates. A position assumed by carrier 30 in the vertical direction is calculated based on the axis of rotation of motor 20 as sensed by encoder 71. For example, how many times wheel 41 rotates is known from how many times motor 20 rotates. How much suspension chain 50 is fed or wound is known from how many times wheel 41 rotates. A position assumed by carrier 30 connected to the lower end of suspension chain 50 is known from how much suspension chain 50 is fed and wound. A speed at which carrier 30 moves is sensed based on a variation with time of the position of carrier 30 thus calculated. Furthermore, a speed at which wheel 41 rotates is known from a speed at which motor 20 rotates. Furthermore, a speed at which suspension chain 50 is fed and wound is known from the speed at which wheel 41 rotates. A speed at which suspension chain 50 moves and hence a speed at which carrier 30 connected to the lower end of suspension chain 50 moves are known from the speed at which suspension chain 50 is fed and wound.

[0023] Quenching apparatus 100 may further comprise an agitator 80. Agitator 80 includes a motor, a rotary shaft, and a propeller. The motor is attached to casing 10 (or cooling bath 11). The rotary shaft is connected to the motor. The rotary shaft extends in cooling bath 11 in the vertical direction. The propeller is connected to the rotary shaft. The propeller is immersed in coolant CL reserved in cooling bath 11. As the motor's rotational power rotates the rotary shaft, the propeller rotates in the coolant. Furthermore, a partition member 81 is disposed in cooling bath 11. As the propeller rotates in the coolant, a flow of liquid is caused in coolant CL, and formed by partition member 81, as desired.Quenching Method Using Quenching Apparatus 100

[0024] Hereinafter, a quenching method using quenching apparatus 100 will be described.

[0025] As shown in FIG. 3, the quenching method using quenching apparatus 100 comprises a preparation step S1. In the preparation step S1, the member to be treated W is prepared. In the preparation step S1, the member to be treated W is subjected to a heat treatment. The member to be treated W is subjected to the heat treatment while the member to be treated W is held at a temperature equal to or higher than the A3 transformation point of the steel constituting the member to be treated W. The member to be treated W may be heated in a carburizing atmosphere such as RX gas or in a carbonitriding atmosphere that is a carburizing atmosphere with ammonia gas or the like added thereto. That is, in the preparation step S1, the member to be treated W may be carburized or carbonitrided. After the heat treatment is performed, the member to be treated W is moved through the second opening of waiting chamber 12 and thus carried on carrier 30 located in waiting chamber 12.

[0026] The quenching method using quenching apparatus 100 further comprises a carrier lowering step S2, a coolant agitation step S3, a holding step S4, and a carrier raising step S5. In the carrier lowering step S2, carrier 30 with the member to be treated W carried thereon is moved in the vertical direction downward. Carrier 30 is moved downward by the rotational power of motor 20 transmitted to carrier 30 via drive mechanism 40. When the member to be treated W is immersed in coolant CL and carrier 30 reaches a predetermined position in the vertical direction, moving carrier 30 downward is stopped, and carrier 30 will be held at the predetermined position.

[0027] The coolant agitation step S3 includes a first step S31. The first step S31 is performed together with the carrier lowering step S2. In the first step S31, agitator 80 is driven to generate a flow of liquid of coolant CL flowing in a vicinity of the member to be treated W from above to below in the vertical direction. The flow of liquid is assumed to have a first speed. Carrier 30 is assumed to be moved in the vertical direction downward at a second speed. The first speed is smaller than or equal to the second speed. The first speed preferably matches the second speed. From another point of view, a difference (or a relative speed) between the first speed and the second speed is smaller than the second speed, and is preferably 0. When the carrier lowering step S2 ends, the first step S31 also ends.

[0028] In the holding step S4, the member to be treated W is held in coolant CL. Martensitic transformation thus proceeds in the member to be treated W. The coolant agitation step S3 further includes a second step S32. The second step S32 starts after the holding step S4 starts when a predetermined period of time elapses. This period of time is previously calculated as at least a period of time elapsing before martensitic formation is started at a surface of the member to be treated W. In the second step S32, agitator 80 is driven again. This causes a flow of liquid of coolant CL and the member to be treated W is cooled at an increased rate, which reduces a period of time required to complete quenching the member to be treated W.

[0029] The carrier raising step S5 is performed after quenching the member to be treated W is completed. In the carrier raising step S5, carrier 30 is moved in the vertical direction upward and returned to waiting chamber 12. Carrier 30 is moved upward by the rotational power of motor 20 transmitted to carrier 30 via drive mechanism 40. After quenching the member to be treated W is completed, the member to be treated W is moved through the first opening of waiting chamber 12 and thus ejected out of quenching apparatus 100. While in the above description the coolant agitation step S3 is performed by way of example, the coolant agitation step S3 (the first step S31 and the second step S32) may not be performed.Variation of Quenching Apparatus 100

[0030] Hereinafter, variations of quenching apparatus 100 will be described.

[0031] As shown in FIG. 4, quenching apparatus 100 may comprise a pump 82 rather than agitator 80 as an agitator. Cooling bath 11 has an inlet 11a and an outlet 11b. A pipe 13a has one end connected to inlet 11a, and a pipe 13b has one end connected to outlet 11b. Pump 82 is connected to the other end of pipe 13a and also connected to the other end of pipe 13b.

[0032] When pump 82 is driven, the coolant reserved in cooling bath 11 is suctioned through inlet 11a, passes through pipe 13a, pump 82 and pipe 13b, and is returned to cooling bath 11 through outlet 11b. As coolant CL thus circulates, coolant CL is agitated in cooling bath 11. The agitator used in quenching apparatus 100 is not limited to agitator 80 and pump 82. Although not shown, the agitator used in quenching apparatus 100 may be a blade.Variation of Quenching Method Using Quenching Apparatus 100

[0033] Hereinafter, a variation of the quenching method using quenching apparatus 100 will be described.

[0034] As shown in FIG. 5, the quenching method using quenching apparatus 100 may not comprise the coolant agitation step S3 including the first step S31. That is, in the carrier lowering step S2, agitator 80 may not be driven to cause a flow of liquid in coolant CL. In that case, when immersing the member to be treated W in coolant CL is started, a vapor layer is formed around the member to be treated W located in coolant CL. The immersion of the member to be treated W is completed for example before the vapor layer disappears. The member to be treated W (or carrier 30) is moved for example to a predetermined position before the vapor layer disappears.Effects of Quenching Apparatus 100

[0035] Quenching apparatus 100 has effects, as described below.

[0036] In the first step S31, a difference (or a relative speed) between the first speed and the second speed can be set to be smaller than the second speed (preferably, zeroed) to reduce strain caused in the member to be treated W. This requires accurately understanding a position assumed by carrier 30 in the vertical direction and a speed at which the carrier moves in the vertical direction. Quenching apparatus 100 has sensor 70 to continuously sense the position assumed by carrier30. Quenching apparatus 100 allows accurately understanding the position assumed by carrier 30 in the vertical direction and the speed at which the carrier moves in the vertical direction without being affected by sagging of suspension chain 50.

[0037] The member to be treated W is a heavy object, and accordingly, suspension chain 50 is required to have a thickness capable of supporting the weight of carrier 30 and that of the member to be treated W. Normally, drive mechanism 40 is disposed outside casing 10, and suspension chain 50 is passed through a through hole formed through casing 10, whereas quenching apparatus 100 has drive mechanism 40 disposed in casing 10 and thus does not require a through hole formed through casing 10 to pass suspension chain 50. However, quenching apparatus 100 requires through hole 12a formed through casing 10 for sensing member 60. However, sensing member 60 is not required to support the weight of carrier 30 and that of the member to be treated W and accordingly, may be thin, so that through hole 12a may have a reduced inner diameter, and this reduces leakage of gas from the interior of casing 10.

[0038] When the first step S31 is not performed, then, to reduce strain of the member to be treated W, carrier 30 is moved (downward) at an increased speed so that before a vapor layer produced around the member to be treated W disappears, immersing and moving the member to be treated W to a predetermined position can be completed to reduce a difference in temperature of the member to be treated W for each location and hence strain of the member to be treated W.

[0039] Although the embodiments of the present invention have been described, it should be understood that the embodiments disclosed herein are illustrative and non-restrictive in any respect. The scope of the present invention is defined by the terms of the claims, and is intended to encompass any modification falling within the meaning and scope equivalent to the terms of the claims.

Claims

1. A quenching apparatus comprising:a casing;a motor that generates rotational power;a carrier that is disposed in the casing and carries a member to be treated;a drive mechanism that is disposed in the casing and transmits the rotational power to the carrier to change a position assumed by the carrier in a vertical direction;a suspension chain that interconnects the drive mechanism and the carrier;a sensing member connected to the carrier and having a sensing unit; anda sensor that senses the position assumed by the carrier based on a position of the sensing unit, whereinthe sensor continuously senses the position assumed by the carrier while the carrier positionally varies in the vertical direction.

2. The quenching apparatus according to claim 1, whereinthe sensing unit is disposed outside the casing, andthe sensor is disposed outside the casing.

3. The quenching apparatus according to claim 2, wherein the casing is provided with a through hole to pass the sensing member therethrough.

4. The quenching apparatus according to claim 3, further comprising a seal member, wherein the seal member seals a gap between an internal wall surface of the through hole and the sensing member.

5. The quenching apparatus according to claim 2, wherein the sensing member is thinner than the suspension chain.

6. The quenching apparatus according to claim 2, wherein the sensor is a distance sensor that senses a distance between the sensing unit and the sensor, and, based on the distance, the sensor senses the position assumed by the carrier in the vertical direction.

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