JP2016069671A - Manufacturing apparatus of cast-iron friction member and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing apparatus of a cast-iron friction member, which allows performing a nitriding treatment in a shorter time compared to a conventional method, applying to a small lot production, and easily adjusting production adjustment, and a manufacturing method of the cast-iron friction member.SOLUTION: A nitriding treatment apparatus 20 includes a gas nitriding furnace 21, a heating apparatus 41, and a gas introduction apparatus 51. The gas nitriding furnace 21 accommodates a disk rotor 10 before the nitriding treatment is performed. The heating apparatus 41 does not heat the whole gas nitriding furnace 21, but heats a friction part 11 of the disk rotor 10 accommodated, and heats each of friction surfaces 13, 14. The gas introduction apparatus 51 introduces nitriding gas into the gas nitriding furnace 21 with each of the friction surfaces 13, 14 heated to maintain a nitriding treatment temperature.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an apparatus for manufacturing a cast iron friction member and a method for manufacturing the same.

  In general, a braking device for a vehicle includes a cast iron friction member such as a disc rotor and a brake drum, and a brake operation unit such as a brake disc pad and a brake shoe. The cast iron friction member is attached to the end of the drive shaft of the vehicle and is configured to rotate together with the wheel. When the vehicle is braked, the brake operating portion is pressed against the sliding portion of the cast iron friction member. Thereby, the rotation of the wheel is braked by the friction generated between them.

  As described above, the cast iron friction member is required to have high wear resistance because friction is generated between the cast iron friction member and the brake operating portion each time the vehicle is braked. At the same time, because of the structure of the braking device, the cast iron friction member is provided in a state of being exposed outside the vehicle, so that corrosion resistance against rust and the like is also required. In particular, if the disc rotor rusts, depending on the wheel design of the vehicle, the corroded state is visible from the outside, so it is not only functional in terms of braking the vehicle but also in terms of appearance. Corrosion resistance is required.

  Therefore, conventionally, in order to improve the corrosion resistance of the friction member made of cast iron, a nitriding treatment is performed in which a nitride layer is formed on the surface (sliding surface) of the sliding portion (see, for example, Patent Document 1). . This conventional nitriding process is called a batch type process, and several hundred to several thousand cast iron friction members are put in a gas nitriding furnace depending on the size of the furnace, and a nitriding gas containing ammonia gas is supplied. However, a nitride layer is formed on the sliding surface by heating the entire inside of the furnace to a predetermined nitriding temperature.

JP 2014-47406 A

  However, the conventional nitriding process requires a processing time of at least several hours to manufacture a product that can withstand practical use, and thus has been problematic in terms of productivity. Moreover, since it is a manufacturing device that puts a large amount of cast iron friction members in a gas nitriding furnace and performs nitriding at once, this is the case when the number of production becomes small due to a decrease in production number or customer demand. When the apparatus is used, loss of nitriding gas and energy is large. For this reason, there is a problem in that it is difficult to adjust the production number.

  Therefore, the present invention provides a manufacturing apparatus and a manufacturing method for a cast iron friction member that can perform nitriding in a shorter time than the prior art, and that can handle small-lot production and that can be easily adjusted for production. Is the main purpose.

  In order to solve the above problems, the following means were adopted.

  In other words, the invention according to claim 1 is an apparatus for manufacturing a cast iron friction member having a portion to be processed that has been subjected to nitriding treatment, wherein the cast iron friction member before being subjected to the nitriding treatment is accommodated. A gas nitriding furnace, a gas introduction part for introducing a nitriding gas into the gas nitriding furnace, and a heating part for heating the to-be-treated part with the to-be-treated part as a heating object without heating the entire gas nitriding furnace And.

  According to the first aspect of the present invention, unlike the conventional nitriding treatment in which the entire gas nitriding furnace is heated to be in a heated atmosphere, the heated portion heats the portion to be treated instead of the entire gas nitriding furnace. Is done.

  Here, ammonia gas is used as the nitriding gas. In this case, only ammonia gas may be used as the nitriding gas, or the ammonia gas may be a mixture of nitrogen gas or carburizing gas. As the carburizing gas, hydrocarbons containing alcohol such as methanol, carbon monoxide, carbon dioxide and the like can be used.

  In general, when a nitriding gas containing ammonia gas as a main component is used, it is called a gas nitriding method, and a relatively hard nitride layer having a Vickers hardness (HV) of about 1000 to 1300 is obtained. On the other hand, when a mixed gas of ammonia gas and carburizing gas is used as a nitriding gas, it is called a gas soft nitriding method, and a nitride layer having a Vickers hardness (HV) of about 500 to 600 is obtained. In the first aspect of the present invention, both the gas nitriding method and the gas soft nitriding method can be employed.

When the nitriding gas is introduced into the gas nitriding furnace, the ammonia gas contained in the nitriding gas becomes unstable in a heating atmosphere having a temperature exceeding 200 ° C., and thermally decomposes as “NH ₃ → N + 3H”. The nascent atomic nitrogen (N) generated by this thermal decomposition combines with iron or the like present on the surface of the portion to be processed, whereby a nitride layer is formed on the surface.

  However, in the conventional nitriding apparatus, the entire inside of the gas nitriding furnace is to be heated, and the entire inside of the furnace is in a heated atmosphere. In that case, thermal decomposition of the ammonia gas occurs even at a location away from the vicinity of the processing target and not used for the nitriding reaction of the processing target. For this reason, the amount of ammonia gas used for the nitriding reaction reaches the vicinity of the portion to be processed, and it takes time to obtain a nitride layer having a desired thickness. In addition, since the nitriding gas is wasted and thermally decomposed and consumed, the amount of the nitriding gas to be introduced also increases, and the use efficiency of the nitriding gas is poor.

  In this regard, in the case of the invention described in claim 1, as described above, the portion to be treated of the friction member made of cast iron is heated as a heating target, not the entire inside of the gas nitriding furnace. Therefore, the ammonia gas contained in the nitriding gas introduced into the furnace is thermally decomposed in the vicinity of the portion to be treated which is in a high temperature state by heating. Thereby, useless thermal decomposition of the introduced ammonia gas is suppressed, and the amount of ammonia gas used for the nitriding reaction on the surface of the processing target is increased. As a result, the nitriding reaction on the surface of the processing target is promoted, and the time for obtaining a nitride layer having a desired thickness can be shortened. In addition, since the processing target is to be heated, the time for the processing target to rise to the set nitriding temperature is shortened. Together, the nitride layer can be formed in a short time.

  Further, since the amount of the nitriding gas that is wasted and thermally consumed without being used in the nitriding reaction on the surface of the processing target portion is reduced, the use efficiency of the nitriding gas can be improved.

  Furthermore, since the to-be-processed part of each friction member made of cast iron is to be heated, it is possible to suppress the loss of nitriding gas, energy, etc. even in the production of a small lot. As a result, it is easy to make production adjustments due to a decrease in the number of production and customer demand. Therefore, not only can the nitriding process be performed in a shorter time than in the prior art, but also the effect of being able to cope with the production of small lots and easily adjusting the production can be obtained.

  According to a second aspect of the present invention, in the first aspect of the present invention, a temperature detection unit that detects a temperature of the processing target portion, and a temperature detected by the temperature detection unit is a set nitriding temperature. And a temperature control unit that controls the temperature of the heating unit.

  According to the second aspect of the present invention, the temperature control unit grasps the temperature of the processing target by detection of the temperature detection unit, and the heating unit is set so that the processing target reaches the set nitriding temperature. Temperature control. As a result, the temperature of the target portion to be subjected to the nitriding process is directly managed, so that a more precise temperature can be set and the thickness of the nitride layer formed on the target portion can be controlled. .

  According to a third aspect of the present invention, in the second aspect of the present invention, the gas introduction unit introduces a nitriding gas into the gas nitriding furnace after the portion to be processed reaches the nitriding temperature. It is a starting point.

  According to the third aspect of the present invention, the nitriding gas is introduced into the gas nitriding furnace after the processing portion reaches the set nitriding temperature by the gas introducing portion. Therefore, the ammonia gas contained in the nitriding gas is thermally decomposed during the process of heating the portion to be processed, and is prevented from being wasted without being used for the nitriding reaction on the surface of the portion to be processed. Thereby, the use efficiency of nitriding gas can further be improved.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the cast iron friction member is a disk rotor, and the treated portion is provided on both front and back surfaces of the disk rotor. The heating portion is provided opposite to each of the sliding surfaces.

  According to the fourth aspect of the present invention, since the heating portion is provided opposite to both the front and back sliding surfaces of the disk rotor, the heating is performed locally targeting both sliding surfaces to be heated. It is possible to suppress heating unevenness. In this way, both sliding surfaces can be heated to a set nitriding temperature while suppressing uneven heating, which can contribute to the promotion of nitriding reaction on both sliding surfaces and the formation of a more uniform nitride layer. .

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects of the present invention, the heating section is provided opposite to the processing target section to radiate heat to the processing target section. It is characterized by including a heat irradiation unit to be executed.

  According to the fifth aspect of the present invention, the portion to be processed is heated by performing heat irradiation from the heat irradiation portion of the heating portion facing the portion to be processed toward the portion to be processed. Thereby, the local heating which made the to-be-processed part the heating object instead of the whole gas nitriding furnace can be performed reliably.

  The invention according to claim 6 is a method of manufacturing a cast iron friction member having a portion to be treated that has been subjected to nitriding treatment, and the cast iron friction member before being subjected to the nitriding treatment is accommodated in a gas nitriding furnace. A gas introducing step for introducing a nitriding gas into the gas nitriding furnace, and a heating step for heating the portion to be treated with the portion to be treated as a heating subject without using the entire gas nitriding furnace as a subject to be heated. It is characterized by providing.

  According to the sixth aspect of the present invention, the heated portion is heated as a heating target rather than the entire gas nitriding furnace, so that the ammonia gas contained in the introduced nitriding gas is heated at or near the treated portion. Decompose. Thereby, useless thermal decomposition of the introduced ammonia gas is suppressed, and the amount of ammonia gas used for the nitriding reaction in the processing target portion is also increased. As a result, the nitriding reaction in the portion to be processed is promoted, and the time for obtaining a nitride layer having a desired thickness can be reduced. In addition, the time required for the portion to be processed to rise to the set nitriding temperature is shortened, and in combination, the nitride layer can be formed in a short time to increase productivity. Moreover, even in the production of small lots, it is possible to suppress the loss of nitriding gas, energy, etc., and it is easy to make production adjustments in accordance with a decrease in the number of production and customer demands.

Sectional drawing which shows a disk rotor. Schematic which shows the nitriding apparatus of a disk rotor. The flowchart which shows the process of a nitriding process. The cross-sectional photograph of the sliding surface of the disk rotor obtained by the Example.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, a disk rotor will be described as an example of a cast iron friction member.

  First, an outline of the disk rotor will be briefly described with reference to FIG.

  FIG. 1 is a cross-sectional view showing a disk rotor, and shows a cross section in the radial direction. As shown in FIG. 1, the disk rotor 10 has a sliding portion 11 and a cylindrical portion 12.

  The sliding portion 11 is made of gray cast iron containing flake graphite, and is formed in a ring shape. Both the front and back surfaces of the sliding portion 11 are a pair of sliding surfaces 13 and 14 that are press-contacted by a disk pad. The sliding surfaces 13 and 14 are nitrided, and a nitride layer having a thickness of 10 to 15 μm is formed. Therefore, the sliding part 11 (more specifically, each sliding surface 13 and 14) is corresponded to the to-be-processed part to which the nitriding process was performed.

  The cylindrical portion 12 has a covered cylindrical shape, and is provided so as to protrude from the inner peripheral portion of the sliding portion 11 in the central axis direction of the cylindrical portion 12. The lid portion of the cylindrical portion 12 is an attachment plate portion 15, and an attachment hole 16 is provided at the center of the attachment plate portion 15. The disk rotor 10 is attached to the hub H provided at the end of the axle S using the attachment plate portion 15 and the attachment hole 16.

  Next, a nitriding apparatus that performs nitriding on the disk rotor 10 will be described with reference to FIG. This nitriding apparatus corresponds to an apparatus for producing a cast iron friction member. By using this nitriding apparatus, a nitride layer is formed on the sliding surfaces 13 and 14 of the sliding portion 11.

  FIG. 2 is a schematic view showing a nitriding apparatus. As shown in FIG. 2, the nitriding apparatus 20 is provided with a gas nitriding furnace 21, a rotor support 31, a heating device 41, and a gas introducing device 51.

  The rotor support 31 is a jig for supporting the disk rotor 10 in the gas nitriding furnace 21. The rotor support 31 has a support shaft 32, and the disk rotor 10 is supported by passing the tip of the support shaft 32 through the mounting hole 16 of the disk rotor 10.

  The heating device 41 is an infrared lamp (near infrared lamp) provided with an infrared irradiation surface 42 for irradiating infrared rays, and corresponds to a heating unit. The heating device 41 has a rectangular parallelepiped appearance, and in this embodiment, four heating devices 41 are provided. Two of the four heating devices (first heating devices) 41a have their longitudinal directions (perpendicular to the paper surface) in the same direction, and sandwich the sliding portion 11 of the disk rotor 10 supported by the rotor support 31. Has been placed. Further, the other two heating devices (second heating devices) 41b are arranged in the same manner, and are provided so as to sandwich the support shaft 32 between the first heating device 41a.

  In addition, each heating device 41 is provided such that the infrared irradiation surface 42 as each heat irradiation unit faces the sliding surfaces 13 and 14 of the sliding unit 11. For this reason, the infrared rays (near infrared rays) irradiated from the heating device 41 are irradiated toward the sliding surfaces 13 and 14 of the sliding portion 11, and the sliding surfaces 13 and 14 are locally heated. Become.

  Each heating device 41 is connected to a heating control device 43 as a temperature control unit, and the heating control device 43 controls the heating of each heating device 41. The heating control device 43 has a temperature detection unit 44 that detects the temperature of the portion made of cast iron with respect to the sliding portion 11 of the disk rotor 10 accommodated in the gas nitriding furnace 21. For example, a thermocouple is used as the temperature detection unit 44. The heating control device 43 controls the heating of each heating device 41 based on the temperature detected by the temperature detection unit 44 so that the sliding unit 11 reaches the set nitriding temperature.

  The gas introduction device 51 is a device that introduces a nitriding gas into the gas nitriding furnace 21. The gas introduction device 51 is connected to a gas introduction path 52 provided in the gas nitriding furnace 21, and a nitriding gas is introduced from the gas introduction apparatus 51 into the gas nitriding furnace 21 through the gas introduction path 52. Note that the gas introduction unit includes a gas introduction device 51 and a gas introduction path 52.

  The gas introduction device 51 is electrically connected to the heating control device 43 and receives information from the heating control device 43 when the sliding portion 11 of the disk rotor 10 reaches a set nitriding temperature. It is like that. Upon receipt of the information, the gas introducing device 51 starts introducing the nitriding gas and continues to supply the nitriding gas until the set time elapses.

  Here, ammonia gas is used as the nitriding gas. In this case, only ammonia gas may be used as the nitriding gas (gas nitriding treatment), or the ammonia gas may be mixed with nitrogen gas or carburizing gas (gas soft nitriding treatment).

  Next, of the manufacturing method of the disk rotor 10, a nitriding process step of nitriding the sliding portion 11 of the disk rotor 10 using the nitriding apparatus 20 will be described with reference to FIG. 3.

  FIG. 3 is a flowchart showing the processing steps of the nitriding treatment. As shown in FIG. 3, first, in the first step S <b> 1, after manufacturing the disk rotor 10 using cast iron, the disk rotor 10 is subjected to pretreatment such as degreasing, and then the rotor support 31. The disc rotor 10 is set in Thereby, the disk rotor 10 before nitriding is accommodated in the gas nitriding furnace 21.

  In the subsequent second step S2, the heat treatment for the disk rotor 10 is performed. In this case, the heating control of the heating device 41 by the heating control device 43 is performed so that the sliding portion 11 of the disk rotor 10 reaches the set nitriding temperature.

  Here, the nitriding temperature of the sliding portion 11 (more specifically, the sliding surfaces 13, 14) is preferably set in the range of 450 ° C to 650 ° C, and set in the range of 500 ° C to 600 ° C. More preferably. When the temperature is set lower than 450 ° C., a nitride layer having a necessary thickness is not formed. When the temperature is set higher than 650 ° C., formation of the nitride layer is promoted, but cracking occurs due to thermal strain. This is because it tends to occur.

  After the sliding portion 11 of the disk rotor 10 reaches the nitriding temperature, a third step S3 as a gas introduction step is performed. In the third step S <b> 3, the gas introduction device 51 moves from the gas introduction path 52 to room temperature while maintaining the temperature of the sliding portion 11 that has reached the set nitriding treatment temperature at the nitriding treatment temperature by the heating control device 43. This nitriding gas is introduced into the gas nitriding furnace 21. The introduction of the nitriding gas is continuously performed for a predetermined time. As a result, the introduced nitriding gas flows into the sliding surfaces 13 and 14 of the sliding portion 11 maintained at a high nitriding temperature and in the vicinity thereof, and the heat of the ammonia gas contained in the nitriding gas there. Decomposition occurs. Atomic nitrogen (N) generated by this thermal decomposition reacts with iron or the like existing on the surfaces of the sliding surfaces 13 and 14, and a nitride layer is formed on each of the sliding surfaces 13 and 14.

  Thereafter, in the fourth step S4, a cooling process for stopping and cooling the disk rotor 10 is performed. After cooling, the disk rotor 10 is taken out from the gas nitriding furnace 21 to obtain the disk rotor 10 in which the nitride layers are formed on the sliding surfaces 13 and 14.

  In both the second step S2 and the third step S3, since the sliding portion 11 is heated by the heating device 41, both steps S2 and S3 correspond to the heating step.

[Example]
After adopting a gas nitriding method using only ammonia gas as a nitriding gas, the nitriding temperature is set to 540 ° C., the time for raising the sliding portion 11 to the nitriding temperature, and the predetermined time for maintaining the nitriding temperature. The total time was set to 20 minutes, and the nitriding process described above was performed using the nitriding apparatus 20.

  The cross sections of the sliding surfaces 13 and 14 of the disk rotor 10 obtained as a result were observed with an electron microscope (SEM). FIG. 4 is an SEM photograph showing the cross section. As shown in the photograph of FIG. 4, a nitride layer 62 having a thickness of about 10 to 12 μm was confirmed on the surface side of the cast iron base material 61. Therefore, the nitride layer 62 having a thickness comparable to that of the conventional nitriding process and a level that can withstand practicality is formed on each of the sliding surfaces 13 and 14 in a relatively short time of 20 minutes. I was able to.

  According to the present embodiment described above, the following excellent effects can be obtained.

  First, the nitriding apparatus 20 of the present embodiment includes a heating device 41 that heats the sliding portion 11 (more specifically, the sliding surfaces 13 and 14) of the disk rotor 10 rather than the entire inside of the gas nitriding furnace 21. I have. Therefore, the ammonia gas contained in the nitriding gas introduced into the gas nitriding furnace 21 is maintained at the nitriding temperature and thermally decomposed at the sliding portion 11 in the high temperature state and the vicinity thereof. Thereby, useless thermal decomposition of the introduced ammonia gas is suppressed, and the amount of ammonia gas used for the nitriding reaction also increases. As a result, the nitriding reaction on the sliding surfaces 13 and 14 is promoted, and the time for obtaining a nitride layer having a desired thickness can be shortened.

  In addition, since the sliding part 11 itself to be subjected to nitriding treatment is the heating target of the heating device 41, the time until the sliding part 11 is heated and reaches the set nitriding temperature is also gas nitriding. Compared with the case where the entire inside of the furnace 21 is to be heated, it can be greatly shortened. Therefore, the above-described reduction in time by promoting the nitriding reaction and the reduction in time for raising the sliding portion 11 to the nitriding treatment temperature are combined to form a nitride layer at a level that can withstand practicality in a short time. be able to.

  In addition, the ammonia gas contained in the nitriding gas is thermally decomposed at and near the sliding portion 11, so that it is wastefully decomposed and consumed without being used for the nitriding reaction on the sliding surfaces 13 and 14. The amount of nitriding gas to be reduced is reduced. Thereby, the use efficiency of nitriding gas can be improved.

  Furthermore, in the nitriding apparatus 20 of this embodiment, since the sliding portions 11 of the individual disk rotors 10 are heated, nitriding is possible even in the production of small lots compared to a large apparatus for batch processing. It can suppress that loss of property gas, energy, etc. arise. As a result, it is easy to make production adjustments due to a decrease in the number of production and customer demand. Therefore, not only the above-described effect that the nitriding treatment can be performed in a shorter time than the conventional method, but also the effect that it is possible to cope with the production of a small lot and the production adjustment is easy.

  In the nitriding apparatus 20 of the present embodiment, the heating control apparatus 43 grasps the temperature of the sliding part 11 by the temperature detection unit 44 and the heating apparatus 41 adjusts the sliding part 11 to the set nitriding temperature. Temperature control is performed. Thereby, since the temperature of the sliding part 11 to be subjected to nitriding treatment is directly managed, a more precise temperature setting is possible, and the thickness of the nitride layer formed on the sliding part 11 can be controlled. it can.

  In the nitriding apparatus 20 of this embodiment, the nitriding gas is introduced into the gas nitriding furnace 21 by the gas introducing apparatus 51 after the sliding portion 11 reaches the set nitriding temperature. . Therefore, ammonia gas contained in the introduced nitriding gas is thermally decomposed during heating until the sliding portion 11 reaches the nitriding temperature, and may be wasted without being used for the nitriding reaction. It is suppressed. Thereby, the use efficiency of nitriding gas can further be improved.

  In the nitriding apparatus 20 of this embodiment, the heating apparatus 41 is disposed so as to face the sliding surfaces 13 and 14 of the disk rotor 10. Therefore, it is possible to locally heat the respective sliding surfaces 13 and 14 to be heated, and it is possible to suppress the occurrence of uneven heating on the respective sliding surfaces 13 and 14. Thus, since each sliding surface 13 and 14 can be heated to the set nitriding temperature while suppressing heating unevenness, the reactivity between cast iron and nitriding gas is improved and a more uniform nitride layer is formed. Can contribute to formation.

  In the nitriding apparatus 20 of the present embodiment, the heating device 41 opposes the sliding surfaces 13 and 14 of the disk rotor 10 and includes an infrared irradiation surface 42 that performs infrared irradiation on the sliding surfaces 13 and 14. Have. By irradiating heat from the infrared irradiation surface 42 toward the sliding surfaces 13, 14, it is possible to reliably perform local heating on the sliding surfaces 13, 14 rather than the entire gas nitriding furnace 21. It can be carried out.

[Other Embodiments]
(1) In the above embodiment, an infrared lamp having an infrared irradiation surface 42 for irradiating infrared rays is used as the heating device 41. However, for example, electromagnetic waves other than infrared rays, such as microwaves, electromagnetic induction, A heating device (heating unit) that heats by energization or the like or heats by a block heater or the like may be used.

  (2) In the above embodiment, the heating device 41 which is an infrared lamp having a rectangular parallelepiped shape is used. However, an annular shape is formed in accordance with the sliding surfaces 13 and 14 of the disk rotor 10 having an annular shape. You may use the heating apparatus (heating part) which has the infrared irradiation surface 42 to make. If such a heating device is used, the entire sliding surfaces 13 and 14 can be uniformly heated to further suppress the occurrence of heating unevenness.

  Moreover, as a structure which heats each sliding surface 13 and 14, the reflective member provided with the reflective surface which opposes any one of each sliding surface 13 and 14 is installed, and heat is irradiated with respect to the reflective member A heating device 41 may be installed. In this case, the reflecting member is placed close to one of the sliding surfaces 13 and 14, and the reflecting surface of the reflecting member is mirror-finished to make the entire sliding surfaces 13 and 14 uniform. It becomes possible to heat. Thereby, since it can be set as the structure which abbreviate | omitted the heating apparatus 41 by the side in which the reflecting member was installed, the power consumption required for manufacture can be reduced.

  (3) In the above embodiment, the gas introduction device 51 introduces the nitriding gas after the sliding portion 11 of the disk rotor 10 reaches the set nitriding temperature. A nitriding gas may be introduced simultaneously with the start. Even in this case, the amount of ammonia gas used for the nitriding reaction of the sliding portion 11 is not different from that of the gas nitriding furnace 21 instead of heating the sliding portion 11 as a heating target. This increases the reactivity between cast iron and nitriding gas. However, in order to prevent the nitriding gas from being thermally decomposed regardless of the nitriding reaction during the heating of the sliding portion 11, the nitriding in which the sliding portion 11 is set as in the present embodiment. It is preferable to introduce the nitriding gas after the processing temperature is reached.

  (4) In the above embodiment, the temperature detecting unit 44 detects the temperature of the sliding part 11, but the sliding part 11 is a sliding surface 13 on which the nitride layer is formed. , 14 may be directly detected.

  (5) In the above embodiment, the heating device 41 is controlled to be heated based on the temperature information detected by the temperature detection unit 44, but a configuration in which the temperature detection unit 44 is omitted may be employed. Thereby, the structure of the nitriding apparatus 20 can be simplified. In this case, the actual temperature of the sliding portion 11 cannot be grasped and precise heating control cannot be performed, but by controlling the output of the heating device 41, the heating time, and the like based on the temperature rise characteristics of cast iron. It is possible to heat the sliding part 11 to a set nitriding temperature.

  (6) In the above embodiment, the disk rotor 10 is described as an example of the cast iron friction member. However, the present invention can also be applied to the case where other cast iron friction members such as a brake drum are manufactured. When applied to a brake drum, the sliding inner surface against which the brake shoe is pressed becomes the part to be treated for nitriding.

  DESCRIPTION OF SYMBOLS 10 ... Disc rotor (cast iron friction member), 11 ... Sliding part (processed part), 13, 14 ... Sliding surface (processed part), 20 ... Nitriding apparatus, 21 ... Gas nitriding furnace, 41 ... Heating Apparatus, 42 ... Infrared irradiation surface (heat irradiation part), 51 ... Gas introduction apparatus (gas introduction part), 52 ... Gas introduction path (gas introduction part).

Claims (6)

An apparatus for producing a friction member made of cast iron having a treated portion subjected to nitriding treatment,
A gas nitriding furnace in which a cast iron friction member before the nitriding treatment is accommodated;
A gas introduction part for introducing a nitriding gas into the gas nitriding furnace;
A heating unit that heats the processing target portion, with the processing target portion as a heating target without setting the entire gas nitriding furnace as a heating target,
An apparatus for manufacturing a cast iron friction member. A temperature detection unit that detects the temperature of the processing target; and
A temperature control unit that controls the temperature of the heating unit such that the temperature detected by the temperature detection unit becomes a set nitriding temperature; and
The apparatus for manufacturing a friction member made of cast iron according to claim 1.   3. The cast iron according to claim 2, wherein the gas introduction part starts introduction of a nitriding gas into the gas nitriding furnace after the part to be treated reaches the nitriding temperature. 4. Friction member manufacturing equipment. The cast iron friction member is a disk rotor, and the processing target is a sliding surface provided on both front and back surfaces of the disk rotor,
The said heating part is provided facing each of the said both sliding surfaces, The manufacturing apparatus of the cast iron friction member of any one of Claim 1 thru | or 3 characterized by the above-mentioned.   The said heating part is provided with the said to-be-processed part, and is provided with the heat irradiation part which performs the heat irradiation to the said to-be-processed part, The Claim 1 characterized by the above-mentioned. Cast iron friction member manufacturing equipment. A method for producing a cast iron friction member having a portion to be treated subjected to nitriding treatment,
A step of accommodating the friction member made of cast iron before being subjected to the nitriding treatment in a gas nitriding furnace;
A gas introduction step of introducing a nitriding gas into the gas nitriding furnace;
A heating step of heating the processing target with the processing target as a heating target without setting the entire gas nitriding furnace as a heating target,
A method for producing a cast iron friction member.