KR20240078219A - A heat treatment device of the ball spline joint and heat treatment method thereof - Google Patents

Abstract

The present invention relates to a heat treatment device for a ball spline joint inner ring unit that heat-treats the ball spline joint inner ring unit by heating or cooling, comprising an inner ring having a plurality of tracks in contact with a ball bearing on the outer peripheral surface, and an inner ring extending integrally from one end of the inner ring. A mounting portion that mounts a ball spline joint inner ring unit consisting of a sleeve with a shaft hole formed therein, and reciprocates in the up and down direction while rotating the ball spline joint inner ring unit during the heat treatment process; An external heat treatment module including an external heating unit provided with a coil for high-frequency induction heating of the track surface of the ball spline joint inner ring unit, and an external cooling unit disposed around the external heating unit to cool the track surface; and an internal heating unit that heats the inner circumferential surface of the shaft hole formed at the rotation center of the ball spline joint inner ring unit, and an internal cooling unit that is inserted into the shaft hole of the ball spline joint inner ring unit and cools the area around the internal heating unit. module; It provides a heat treatment device for a ball spline joint inner ring unit, comprising:
In addition, the present invention provides heat treatment by heating or cooling a ball spline joint inner ring unit consisting of an inner ring having a plurality of tracks in contact with a ball bearing on the outer peripheral surface, and a sleeve that extends integrally from one end of the inner ring and has a shaft hole formed therein. A method of heat treating a ball spline joint inner ring unit, comprising: mounting the ball spline joint inner ring unit on a holder; heating the track surface; cooling the track surface; Heating the inner peripheral surface of the shaft hole formed in the sleeve; and cooling the inner peripheral surface of the shaft hole. It provides a heat treatment method for a ball spline joint inner ring unit comprising a.

Description

Heat treatment device and heat treatment method of the ball spline joint inner ring unit {A heat treatment device of the ball spline joint and heat treatment method thereof}

The present invention relates to a heat treatment device and a heat treatment method for a ball spline joint inner ring unit, and more specifically, to a heat treatment device and a heat treatment method for a ball spline joint inner ring unit that can simultaneously heat treat the exterior and interior of the ball spline joint inner ring unit. will be.

Generally, a trunnion for a constant velocity joint is a trunnion that is inserted into a housing (1) integrally connected to the main shaft (3) and a track (2) formed inside the housing (1) and splined to the driven shaft to transmit power. It is inserted into the trunnion 20 and the three journal parts 22 of the trunnion 20, and occurs between the track 2 of the housing 1 and the journal part 22 of the trunnion 20. It consists of a roller assembly (23) to absorb relative motion.

When the main shaft 3 and the driven shaft of this constant velocity joint are bent to each other, relative motion occurs between the track 2, the trunnion 20, and the roller assembly 23 of the housing 1, and this Friction occurs due to relative motion. The friction generated from the relative motion of the trunnion (20) and the roller assembly (23) can cause wear of the trunnion journal portion (22), and the friction transmitted from the main shaft (3) can cause wear. The driving force may cause deformation or damage to the trunnion.

Therefore, in order to compensate for deformation or damage of the track 2 or the main shaft 3 due to wear, wear resistance performance and strength can be improved through a carburizing heat treatment process.

However, when performing a carburizing heat treatment process, internal axial thermal strain may increase due to long-term heating, and thermal strain distribution in each area occurs due to differences in the thickness of the housing or main shaft, and deep areas may occur in some areas of the thin housing. The problem of increased brittleness due to increased hardness has been pointed out.

Korean Patent No. 10-2386873 (registered on April 11, 2022)

The present invention is intended to solve this problem, and more specifically, by improving the heat treatment process to heat treat the outer peripheral surface of the inner ring of the ball spline joint inner ring unit and the inner peripheral surface of the shaft hole of the sleeve, respectively, to improve wear resistance and strength within the part. The purpose is to provide a heat treatment device and a heat treatment method for a ball spline joint inner ring unit that can prevent thermal deformation by selectively performing heat treatment only on parts that require performance and avoiding heat treatment on parts that do not require heat treatment.

The present invention to solve this problem is a heat treatment device for a ball spline joint inner ring unit that heat-treats the ball spline joint inner ring unit by heating or cooling, comprising an inner ring having a plurality of tracks on the outer peripheral surface in contact with a ball bearing, and one of the inner rings. A mounting portion that mounts a ball spline joint inner ring unit consisting of a sleeve that extends integrally from the side end and has a shaft hole formed therein, and reciprocates in the up and down direction while rotating the ball spline joint inner ring unit during the heat treatment process; An external heat treatment module including an external heating unit provided with a coil for high-frequency induction heating of the track surface of the ball spline joint inner ring unit, and an external cooling unit disposed around the external heating unit to cool the track surface; and an internal heating unit that heats the inner circumferential surface of the shaft hole formed at the rotation center of the ball spline joint inner ring unit, and an internal cooling unit that is inserted into the shaft hole of the ball spline joint inner ring unit and cools the area around the internal heating unit. module; It provides a heat treatment device for a ball spline joint inner ring unit, comprising:

The external cooling unit includes a first cooling member that is integrated with the external heating unit and sprays coolant on the track surface, and is disposed below the first cooling member to distribute coolant supplied from a path different from the first cooling member to the track. It may include a second cooling member sprayed on the surface.

The first cooling member has a ring shape surrounding the track surface and can spray coolant in a downward direction toward the center of rotation of the ball spline joint inner ring unit.

The external heat treatment module performs heating and cooling from one end to the other end of the inner ring of the ball spline joint inner ring unit, and the internal heat treatment module heats and cools from one end to the other end of the sleeve of the ball spline joint inner ring unit. Performing the process, the first area heat-treated by the external heat treatment module and the second area heat-treated by the internal heat treatment module are arranged to overlap corresponding to the front and rear longitudinal directions of the inner ring, and the first area and the second area are They can be heat treated so that they do not meet each other within the thickness range of the inner ring.

The second area may be spaced apart from one end and the other end of the sleeve inwardly at a set interval along the longitudinal direction.

The internal heat treatment module may include the internal heating unit inserted into the shaft hole, and a fixing plate for fixing the internal cooling unit inside or outside the shaft hole.

The internal cooling unit includes a third cooling member inserted into the shaft hole and fixed to the fixing plate, and a third cooling member that sprays coolant on the outside of the sleeve and is fixed to the fixing plate to move in the vertical direction at the same time as the third cooling member. 4May include a cooling member.

The heat treatment device for the ball spline joint inner ring unit may further include a smoke discharge unit disposed adjacent to the external heating unit or the internal heating unit to suck in and discharge smoke generated in the process of heat treating the ball spline joint inner ring unit.

The heat treatment device for the ball spline joint inner ring unit may further include an upper jig coupled to cover at least a portion of the upper side of the shaft hole or the upper side of the track surface in the process of heat treating the track surface of the ball spline joint inner ring unit. .

In addition, the present invention provides heat treatment by heating or cooling a ball spline joint inner ring unit consisting of an inner ring having a plurality of tracks in contact with a ball bearing on the outer peripheral surface, and a sleeve that extends integrally from one end of the inner ring and has a shaft hole formed therein. A method of heat treating a ball spline joint inner ring unit, comprising: mounting the ball spline joint inner ring unit on a holder; heating the track surface; cooling the track surface; Heating the inner peripheral surface of the shaft hole formed in the sleeve; and cooling the inner peripheral surface of the shaft hole. It provides a heat treatment method for a ball spline joint inner ring unit, comprising:

The steps of heating and cooling the track surface include heating and cooling from one end to the other end of the inner ring of the ball spline joint inner ring unit, and the steps of heating and cooling the inner peripheral surface of the shaft hole are performed on the ball spline joint inner ring unit. Heating and cooling are performed from one end to the other end of the sleeve of the joint inner ring unit, and the first area heat-treated in the step of heating the track surface and the second area heat-treated in the step of heating the inner peripheral surface of the shaft hole are the inner ring. are arranged to overlap in the front and rear longitudinal directions, and the first and second regions may be heat treated so as not to meet each other within the thickness range of the inner ring.

The second area may be spaced apart from one end and the other end of the sleeve inwardly at a set interval along the longitudinal direction.

The heat treatment method of the ball spline joint inner ring unit may further include the step of mounting an upper jig to cover the top of the shaft hole or at least a portion of the top side of the track surface before heating the track surface.

The heat treatment method of the ball spline joint inner ring unit includes at least one or a plurality of steps among heating the track surface, cooling the track surface, heating the inner peripheral surface of the shaft hole, and cooling the inner peripheral surface of the shaft hole. It may further include a smoke discharge step of inhaling and discharging smoke generated during the heat treatment or cooling process.

According to the heat treatment device and heat treatment method of the ball spline joint inner ring unit according to an embodiment of the present invention,

First, the outer peripheral surface of the inner ring of the ball spline joint inner ring unit and the inner peripheral surface of the shaft hole inside the sleeve can be heat treated separately through a heat treatment device using high-frequency induction heating, so thermal deformation does not occur in the deep area between the outer peripheral surface of the inner ring and the inner peripheral surface of the shaft hole. Precise heat treatment can be performed to prevent

Second, it can prevent unnecessary parts between the outer peripheral surface of the inner ring and the inner peripheral surface of the shaft hole from being deformed due to heat treatment.

Third, it is easy to form a non-hardened area adjacent to both ends on the inner peripheral surface of the shaft hole,

Fourth, unlike the carburizing heat treatment process, heat treatment through high-frequency induction heating has the effect of significantly shortening the heat treatment process period.

Figure 1 is a reference diagram showing a trunnion for a constant velocity joint heat treated through a conventional carburizing heat treatment process.
Figure 2 is a perspective view showing an external heat treatment module for heat treating the outer peripheral surface of the inner ring of a ball spline joint inner ring unit according to an embodiment of the present invention.
FIG. 3 is a perspective view showing a state in which the ball spline joint inner ring unit shown in FIG. 2 is heat treated while being lowered.
FIG. 4 is a cross-sectional view showing a state in which the outer peripheral surface of the inner ring of the ball spline joint inner ring unit shown in FIG. 3 is heat treated.
Figure 5 is a perspective view showing an internal heat treatment module for heat treating the inner peripheral surface of the shaft hole inside the sleeve of the ball spline joint inner ring unit according to an embodiment of the present invention.
FIG. 6 is a cross-sectional view showing an internal heat treatment module for heat treating the inner peripheral surface of the shaft hole of the ball spline joint inner ring unit shown in FIG. 5.
FIG. 7 is a perspective view showing a state in which the internal heat treatment module is lowered and heat treated inside the ball spline joint inner ring unit shown in FIG. 5.
FIG. 8 is a cross-sectional view showing an internal heat treatment module for heat treating the inner peripheral surface of the shaft hole of the ball spline joint inner ring unit shown in FIG. 7.
Figure 9 is a flow chart showing a heat treatment method for the ball spline joint inner ring unit of the present invention.
Figures 10 and 11 are reference photos showing a ball spline joint inner ring unit heat-treated through the heat treatment apparatus and heat treatment method of the ball spline joint inner ring unit of the present invention.
Figure 12 is a reference diagram showing cross-sections of a conventional carburizing heat-treated ball spline joint inner ring unit (left) and a ball spline joint inner ring unit heat-treated by the heat treatment method (high-frequency heating) of the present invention (right).

Since the present invention can be subject to various changes and can have various embodiments, specific embodiments will be illustrated and described in the drawings.

However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

Terms containing ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by the terms.

The above terms are used only for the purpose of distinguishing one component from another.

For example, the second component may be referred to as the first component without departing from the scope of the present invention, and similarly, the first component may also be referred to as the second component.

The term and/or includes any of a plurality of related stated items or a combination of a plurality of related stated items.

When a component is said to be "connected" or "connected" to another component, it is understood that it may be directly connected to or connected to the other component, but that other components may exist in between. It should be.

On the other hand, when it is mentioned that a component is “directly connected” or “directly connected” to another component, it should be understood that there are no other components in between.

The terms used in this application are only used to describe specific embodiments and are not intended to limit the invention.

Singular expressions include plural expressions unless the context clearly dictates otherwise.

In this application, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Hereinafter, embodiments will be described in detail with reference to the attached drawings, but identical or corresponding components will be assigned the same reference numbers regardless of reference numerals, and duplicate descriptions thereof will be omitted.

The heat treatment apparatus 10 of the ball spline joint inner ring unit according to an embodiment of the present invention includes a mounting portion 100, an external heat treatment module 200, and an internal heat treatment module 300. Hereinafter, the mounting portion, the external heat treatment module for heat treating the inner ring of the ball spline joint inner ring unit, and the internal heat treatment module for heat treating the inner peripheral surface of the shaft hole inside the sleeve of the ball spline joint inner ring unit will be described sequentially.

Although not shown in the drawing, it is preferable that the heat treatment device for the ball spline joint inner ring unit consists of a mounting portion, an external heat treatment module, and an internal heat treatment module as a set in one device.

Figure 2 is a perspective view showing an external heat treatment module for heat treating the outer peripheral surface of the inner ring of a ball spline joint inner ring unit according to an embodiment of the present invention, and Figure 3 shows a state in which the ball spline joint inner ring unit shown in Figure 2 is heat treated while lowering. It is a perspective view, and FIG. 4 is a cross-sectional view showing a state in which the outer peripheral surface of the inner ring of the ball spline joint inner ring unit shown in FIG. 3 is heat treated.

Referring to FIGS. 2 to 4 , a mounting portion 100 and an external heat treatment module 200 among the heat treatment devices for the ball spline joint inner ring unit are shown.

First, the ball spline joint inner ring unit 1 includes an inner ring 2 having a plurality of tracks 3 in contact with ball bearings on the outer peripheral surface, integrally extending from one end of the inner ring 2, and a shaft hole 5 inside. ) consists of a sleeve (4) formed. That is, the inner ring 2 may be further integrally provided on one outer peripheral surface of the sleeve 4 where the shaft hole 5 is formed. In addition, splines 6 may be formed on the inner peripheral surface of the shaft hole 5 so that the shaft (not shown) can be axially coupled.

The mounting portion 100 is an area where the ball spline joint inner ring unit 1 is mounted. After the ball spline joint inner ring unit 1 is mounted, the ball spline joint inner ring unit 1 can be rotated or reciprocated in the vertical direction. It can be configured to move. In this embodiment, it is explained that the mounting part 100 is lifted up and down relative to the external heat treatment module 200, but the present invention is not limited to this and the external heat treatment module 200 is lifted up and down relative to the mounting part 100. It may be configured to do so.

Therefore, although not shown in the drawing, the mounting part 100 includes a rotating part (not shown) that rotates the ball spline joint inner ring unit 1, and an elevating part (not shown) that drives the mounting part to move relative to the vertical direction. do. Of course, the rotating part can be implemented through a motor rotation shaft driven by a gear, belt, or chain, and the lifting part can be implemented through a hydraulic or pneumatic cylinder or gear driven.

And, the external heat treatment module 200 includes an external heating unit 210, an external cooling unit 220, and a fixing plate 230 on which the external heating unit 210 and the external cooling unit 220 are installed.

The external heating unit 210 has a ring-shaped conduit or duct structure, has a coil 211 disposed therein, and is disposed adjacent to the inner ring 2 of the ball spline joint inner ring unit 1. The external heating unit 210 rapidly heats the outer peripheral surface of the inner ring 2 when power is applied from the outside. At this time, the mounting part 100 can be moved from the top to the bottom or from the bottom to the top based on the external heating unit 210 to constantly heat the outer circumference of the inner ring 2 so that the outer circumference of the inner ring 2 is not heated locally. there is.

The external cooling unit 220 includes a first cooling member 221 and a second cooling member 222.

The first cooling member 221 may be integrated with the external heating unit 210. That is, the first cooling member 221 is arranged to surround the coil 211 of the external heating unit 210 and sprays coolant around the external heating unit 210. Accordingly, the first cooling member 221 is shaped to surround the ring-shaped external heating unit 210 and can spray coolant along the circumferential direction of the inner ring 2.

The second cooling member 222 is disposed below the first cooling member 221 and sprays coolant supplied through a different path from the first cooling member 221 onto the surface of the inner ring 2. Of course, the first cooling member 221 and the second cooling member 222 may receive coolant from the same path.

The second cooling member 222 has a ring shape like the first cooling member 221, but has the same width (or thickness) and may have a larger diameter than the diameter of the first cooling member 221. Therefore, since the gap between the second cooling member 222 and the inner ring 2 is formed larger than the gap between the inner ring 2 and the first cooling member 221, the inner ring 2 and the second cooling member 222 ) The coolant can be discharged more smoothly in the area between.

At this time, the spray surface of the first cooling member 221 is disposed in a direction inclined downward with respect to the outer peripheral surface of the inner ring 2 and sprays coolant so as to be inclined downward toward the center of rotation of the ball spline joint inner ring unit 1. You can. Therefore, even when coolant is sprayed from the external cooling unit 220, it is possible to prevent a large amount of coolant from splashing onto the external heating unit 210 or the top of the first cooling member 221, and the coolant reflected from the surface of the inner ring 2 can be supplied again to the lower surface of the inner ring (2).

In the process of heat treating the inner ring 2 of the ball spline joint inner ring unit 1, one end of the inner ring 2 may be heat treated by the external heat treatment module 200 or the internal heat treatment module 300. To prevent this, an upper jig (7) is attached to one end of the inner ring (2) to prevent the entire tip (8), where the outer peripheral surface of the inner ring (2) and the inner peripheral surface of the sleeve (4) are adjacent to each other, from being heat treated. there is.

In other words, the heat treatment area of the tip 8 of the inner ring 2 side of the ball spline joint inner ring unit 1 may partially overlap due to the heat treatment process of the inner ring 2 and the shaft hole heat treatment process, and in this case, the heat treatment overlaps. Alternatively, because brittleness increases in the overlapping tip 8 region, an upper jig 7 is mounted during the heat treatment process to prevent the tip 8 side of the inner ring 2 from being heat treated multiple times. Of course, a non-hardened area is formed in some areas of the inner circumferential surface adjacent to the tip of the sleeve opposite to the tip 8 on the inner ring 2 side to prevent heat treatment. For this purpose, the external heat treatment module 200 and the internal heat treatment module 300 are Heating may not occur at the set depth (or length) at both ends in response to the non-hardening area. For example, the non-hardened area may be an area where a retaining washer (not shown) that does not require hardness through heat treatment is coupled.

A smoke discharge unit 400 is provided around the ball spline joint inner ring unit 1 to suck in and discharge smoke generated during the heat treatment process. The smoke discharge unit 400 is roughly shaped like a pipe and can discharge smoke and water vapor generated during heating or cooling to the outside. Of course, the smoke discharge unit 400 may operate to exhaust smoke and water vapor to the outside when both the external heat treatment module 200 and the internal heat treatment module 300 are operated.

Figure 5 is a perspective view showing an internal heat treatment module for heat treating the inner peripheral surface of the shaft hole inside the sleeve of the ball spline joint inner ring unit according to an embodiment of the present invention, and Figure 6 is the inner peripheral surface of the shaft hole of the ball spline joint inner ring unit shown in Figure 5. It is a cross-sectional view showing the internal heat treatment module for heat treatment, and FIG. 7 is a perspective view showing a state in which the internal heat treatment module is heat treated while descending inside the ball spline joint inner ring unit shown in FIG. 5, and FIG. 8 is a ball spline shown in FIG. 7. This is a cross-sectional view showing an internal heat treatment module that heat treats the inner peripheral surface of the shaft hole of the joint inner ring unit.

Referring to FIGS. 5 to 8, the internal heat treatment module 300 can heat treat the inner peripheral surface of the shaft hole 5 of the ball spline joint inner ring unit 1. Since splines 6 are formed on the inner peripheral surface of the shaft hole 5, heat treatment is required to couple the shaft to the shaft (not shown).

A ball spline joint inner ring unit 1 is mounted on the mounting portion 100, and at this time, an upper jig is not mounted on the ball spline joint inner ring unit 1 for heat treatment of the shaft hole 5. A plurality of protrusions 110 are formed inside the mounting portion 100 so that the other end of the ball spline joint inner ring unit 1 is supported at a set depth, and a communication area around the protruding portion 110 with the outside of the mounting portion 100 is provided. A plurality of cooling water discharge holes 120 are formed to do so.

When coolant is supplied inside the ball spline joint inner ring unit 1, the coolant discharge hole 120 may serve as a flow path through which the cooled coolant is discharged to the outside through the coolant discharge hole 120. Since the mounting portion 100 rotates during the heat treatment process of the ball spline joint inner ring unit 1, the coolant supplied inside the mounting portion 100 is discharged through the coolant discharge hole ( 120) and is discharged to the outside.

In addition, the mounting portion 100 is provided with a plurality of slits 130 passing through the outer peripheral surface so that at least part of the sleeve 4 is exposed. The slit 130 is used as a space through which coolant flows by the internal cooling unit, which will be described later.

Although not shown in the drawing, the mounting portion 100 and the internal heat treatment module 300 can heat treat the inner peripheral surface of the ball spline joint inner ring unit 1 while moving relative to each other in the vertical direction.

The internal heat treatment module 300 includes an internal heating unit 310 that heats the inner peripheral surface of the shaft hole 5, an internal cooling unit 320 that cools the area around the internal heating unit 310 inside or outside the shaft hole 5, and , includes a fixing plate 330 that fixes the internal heating unit 310 and the internal cooling unit 320.

The internal heating unit 310 is formed to have a corresponding length so that the coil 311 can move from one end of the sleeve 4 to the other end.

At this time, the internal cooling unit 320 includes a third cooling member 321 inserted into the shaft hole 5, and a fourth cooling member 322 that cools the outer peripheral surface of the sleeve 4 and the surrounding area of the mounting portion 100. Includes.

The third cooling member 321 extends downward on the fixing plate 330 in parallel with the internal heating unit 310, and is inserted into the shaft hole 5 during the internal heat treatment process. Therefore, the internal heating unit 310 and the inner peripheral surface of the shaft hole 5 can be directly cooled. In addition, the coolant sprayed from the third cooling member 321 is discharged to the outside through the coolant discharge hole 120 of the above-described mounting portion, and a portion may be discharged through the upper part of the shaft hole 5. The coolant sprayed from the third cooling member 321 may be sprayed in a downward slope from the vertical center line of the shaft hole 5 toward the inner peripheral surface of the shaft hole 5.

The fourth cooling member 322 is spaced apart from the bottom of the fixing plate 330 to correspond to the height of the coil 311 of the internal heating unit 310, and is arranged to surround the outside of the mounting unit 100 in a ring shape.

The fourth cooling member 322 sprays coolant toward the outer peripheral surface of the mounting portion 100 and the sleeve 4, and some of the coolant is sprayed directly onto the outer peripheral surface of the sleeve 4 through the slit 130 of the mounting portion 100. Can be sprayed.

In the drawing, the ball spline joint inner ring unit 1 is shown as an example mounted on the mounting portion 100 so that the inner ring 2 is disposed on the upper side, but the ball spline joint inner ring unit ( 1) can also be mounted on the mounting unit 100. In this case, the inner ring 2 is located inside the mounting portion 100, and the structure of the plurality of tracks 3 formed on the outer peripheral surface of the inner ring 2 has the advantage of securing more space for coolant to flow in. .

Figure 9 is a flow chart showing a heat treatment method for the ball spline joint inner ring unit of the present invention.

Hereinafter, a heat treatment method for a ball spline joint inner ring unit according to an embodiment of the present invention will be described.

Referring to FIG. 9, the heat treatment method (S100) of the ball spline joint inner ring unit includes the steps of mounting the ball spline joint inner ring unit on a holder (S110), heating the track surface of the inner ring (S120), and heating the track surface of the inner ring (S120). It includes cooling the surface (S130), heating the inner peripheral surface of the shaft hole (S140), and cooling the inner peripheral surface of the shaft hole (S150).

Between the step of mounting the ball spline joint inner ring unit (S110) and the step of heating the track surface of the inner ring (S120), a step (S111) of mounting an upper jig to cover the top of one end of the inner ring or the top of the shaft hole is included. .

And, smoke or water vapor generated in at least one or a plurality of steps of heating the track surface (S120) and cooling (S130), heating the inner peripheral surface of the shaft hole (S140), and cooling (S150). It further includes a smoke discharge step (S121) of inhaling and discharging.

In the step of heating the track surface (S120) and the step of cooling (S130), it is preferable that heating and cooling are performed from one end to the other end of the inner ring of the ball spline joint inner ring unit. Of course, heating and cooling may occur from the other end of the inner ring to one end in the opposite direction.

In addition, in the step of heating (S140) and the step of cooling (S150) the inner peripheral surface of the shaft hole, it is preferable that heating and cooling are performed from one end to the other end of the sleeve of the ball spline joint inner ring unit. Of course, heating and cooling may be performed in the opposite direction from the tee end to one end of the shaft hole.

In addition, during this heat treatment process, an area where the retaining washers are joined is formed inside the ends of both sides of the inner peripheral surface of the shaft hole. It is preferable that this part is not subjected to heat treatment as it is an unhardened area.

In addition, in the step of heating the track surface (S120) and the step of cooling (S130), the first area (see FIG. 10, A1) heat-treated and the inner peripheral surface of the shaft hole are heated (S140) and the cooling step (S150). The heat-treated second area (see FIG. 10, A2) overlaps in the front-to-back longitudinal direction of the inner ring excluding the non-hardened area (see FIG. 10, A3), and the first area (A1) and the second area (A2) are It is desirable to set them so that they do not meet each other within the thickness range of the inner ring (up to the maximum depth range).

Figures 10 and 11 are reference photos showing a ball spline joint inner ring unit heat-treated through the heat treatment apparatus and heat treatment method of the ball spline joint inner ring unit of the present invention.

Looking at FIG. 10, the degree of heat treatment of the heat-treated ball spline joint inner ring unit 1 can be confirmed by color on the cross section.

Looking at the cross-section and longitudinal cross-section, it can be seen that the surface of the track (3) of the inner ring (2) and the inner peripheral surface of the shaft hole (5) have changed to a darker color, respectively. In addition, in the cross section ①, it can be seen that the heat treated sections on both sides do not meet each other within the thickness range of the inner ring (2), and in the cross section ②, the heat treated section on the inner peripheral surface of the shaft hole (5) is within the thickness range of the sleeve. You can check that.

Looking at this in longitudinal cross-section, it can be seen that in longitudinal cross-section ①, the thickness of the heat-treated area of the track and the heat-treated area of the inner peripheral surface of the shaft hole do not exceed the thickness range of the inner ring and do not meet in the middle. In addition, it can be seen that the range of the heat treatment area described above is clearly visible in longitudinal section ② and longitudinal section ③.

Referring to FIG. 11, the ball spline joint inner ring unit shown in FIG. 10 is shown in an enlarged form.

In cross section ① and cross section ②, it can be seen that the gap between the bottom of the track and the bottom of the spline has not been heat treated, and the thickness of the heat treated area and the thickness of the non-heat treated area remain constant.

In addition, in longitudinal section ① and longitudinal section ②, it can be seen that an unhardened area is formed at one end of the inner ring and one end of the sleeve, and the hardness of the unhardened area is HV446, and the hardness of the hardened area is approximately HV650~660. You can check that it happens.

Of course, it can also be confirmed that the range (or length) of the non-hardened area can be adjusted across the primary and secondary sections in longitudinal section ②.

Therefore, according to the heat treatment device and heat treatment method of the ball spline joint inner ring unit according to an embodiment of the present invention, the outer peripheral surface of the inner ring of the ball spline joint inner ring unit and the inner peripheral surface of the shaft hole inside the sleeve are respectively formed through a heat treatment device using high-frequency induction heating. Since it can be heat treated, precise heat treatment can be performed to prevent heat deformation from occurring in the deep part between the outer circumference of the inner ring and the inner circumference of the shaft hole, and it can prevent unnecessary parts between the outer circumference of the inner ring and the inner circumference of the shaft hole from being deformed due to heat treatment. It is easy to form a non-hardened area adjacent to both ends on the inner peripheral surface of the shaft hole, and unlike the carburizing heat treatment process, heat treatment is performed through high-frequency induction heating, which has the effect of significantly shortening the heat treatment process period.

Figure 12 is a reference diagram showing cross-sections of a conventional carburizing heat-treated ball spline joint inner ring unit (left) and a ball spline joint inner ring unit heat-treated by the heat treatment method (high-frequency heating) of the present invention (right).

Referring to FIG. 12, the ball spline joint inner ring unit heat treated using a conventional heat treatment method has dark black areas and splines heat treated on the bottom of the track in cross section ① and cross section ②, as shown in the left carburized (SCr420H round bar) row of the drawing. It can be seen that the heat-treated dark black areas on the bottom are arranged adjacent to each other and partially overlap with the non-heat-treated areas. In this case, there is a concern that brittleness may increase as the core hardness increases in the thin tube section.

In addition, in longitudinal section ②, there is a problem in that non-hardened areas are not formed at one end of the sleeve and the other end of the sleeve, and the hardness inevitably increases over the entire external area.

In contrast, the ball spline joint inner ring unit heat treated using the heat treatment method of the present invention has a dark gray area heat treated on the bottom of the track in cross section ① and cross section ②, as shown in the high frequency (S53C hot forging/quenching) row on the right side of the drawing. It can be seen that the heat-treated dark gray areas on the bottom of the spline are clearly spaced apart from each other, and through this, it can be seen that an unheat-treated area is secured between the heat-treated areas on both sides. In other words, even if hardness increases through heat treatment, brittleness does not occur.

In addition, in longitudinal section ②, it can be seen that an unhardened area (or range) is formed at one end of the inner ring and one end of the sleeve, and the hardness of the non-hardened area is HV513 or less, and is about 5 mm or less from one end of the sleeve, It can be seen that it is formed at about 3.3mm at the other end. In other words, since selective heat treatment is possible for each area, there is an advantage of being able to control the heat treatment area and the non-hardening area (non-heat treatment area).

Therefore, according to the heat treatment device and heat treatment method of the ball spline joint inner ring unit according to an embodiment of the present invention, the outer peripheral surface of the inner ring of the ball spline joint inner ring unit and the inner peripheral surface of the shaft hole inside the sleeve are respectively formed through a heat treatment device using high-frequency induction heating. Because selective heat treatment is possible, precise heat treatment can be performed to prevent thermal deformation from occurring in the deep part between the outer circumferential surface of the inner ring and the inner circumferential surface of the shaft hole, and to prevent unnecessary parts between the outer circumferential surface of the inner ring and the inner circumferential surface of the shaft hole from occurring due to heat treatment. This can be prevented, and it is easy to form a non-hardened area adjacent to both ends on the inner peripheral surface of the shaft hole. Unlike the carburizing heat treatment process, heat treatment through high-frequency induction heating has the effect of significantly shortening the heat treatment process period.

As described above, the present invention has been described with reference to the embodiments shown in the drawings, but this is only for illustrating the invention, and those skilled in the art may make various modifications or equivalents from the detailed description of the invention. It will be appreciated that one embodiment is possible. Therefore, the true scope of rights of the present invention must be determined by the technical spirit of the patent claims.

10: Heat treatment device
100: Mounting part
200: External heat treatment module
300: Internal heat treatment module
400: smoke exhaust part

Claims (14)

In the heat treatment device for the ball spline joint inner ring unit, which heat-treats the ball spline joint by heating or cooling,
It holds a ball spline joint inner ring unit consisting of an inner ring formed with a plurality of tracks on the outer peripheral surface in contact with a ball bearing, and a sleeve that extends integrally from one end of the inner ring and has a shaft hole formed therein. During the heat treatment process, the ball spline joint inner ring is formed. A mounting portion that reciprocates in the vertical direction while rotating the unit;
An external heat treatment module including an external heating unit provided with a coil for high-frequency induction heating of the track surface of the ball spline joint inner ring unit, and an external cooling unit disposed around the external heating unit to cool the track surface; and
An interior comprising an internal heating unit that selectively heats the inner peripheral surface of the shaft hole formed at the rotation center of the ball spline joint inner ring unit, and an internal cooling unit that is inserted into the shaft hole of the ball spline joint inner ring unit and cools the area around the internal heating unit. heat treatment module;
A heat treatment device for a ball spline joint inner ring unit comprising a. In claim 1,
The external cooling unit,
A first cooling member provided integrally with the external heating unit and spraying coolant on the track surface;
A heat treatment device for a ball spline joint inner ring unit, comprising a second cooling member disposed below the first cooling member and spraying coolant supplied from a path different from that of the first cooling member onto the track surface. In claim 2,
The first cooling member is
A heat treatment device for a ball spline joint inner ring unit, which is formed in a ring shape surrounding the track surface and sprays coolant in a downward direction toward the rotation center of the ball spline joint inner ring unit. In claim 1,
The external heat treatment module performs heating and cooling from one end to the other end of the inner ring of the ball spline joint inner ring unit,
The internal heat treatment module performs heating and cooling from one end to the other end of the sleeve of the ball spline joint inner ring unit,
The first area heat treated by the external heat treatment module and the second area heat treated by the internal heat treatment module are arranged to overlap corresponding to the front and rear lengths of the inner ring,
Heat treatment device for a ball spline joint inner ring unit, characterized in that the first region and the second region are heat treated so that they do not meet each other within the thickness range of the inner ring. In claim 4,
The second area is,
A heat treatment device for a ball spline joint inner ring unit, characterized in that one end and the other end of the sleeve are spaced apart at a set interval inward along the longitudinal direction. In claim 1,
The internal heat treatment module is,
A heat treatment device for a ball spline joint inner ring unit, comprising: the internal heating unit inserted into the shaft hole, and a fixing plate for fixing the internal cooling unit inside or outside the shaft hole. In claim 6,
The internal cooling unit,
a third cooling member inserted into the shaft hole and fixed to the fixing plate;
A heat treatment device for a ball spline joint inner ring unit, characterized in that it sprays coolant on the outside of the sleeve and includes a fourth cooling member fixed to the fixing plate to move in the vertical direction at the same time as the third cooling member. In claim 1,
A heat treatment device for a ball spline joint inner ring unit, further comprising a smoke discharge unit disposed adjacent to the external heating unit or the internal heating unit and sucking in and discharging smoke generated in the process of heat treating the ball spline joint inner ring unit. In claim 1,
A heat treatment device for a ball spline joint inner ring unit, further comprising an upper jig coupled to cover at least a portion of the top of the shaft hole or the top side of the track surface in the process of heat treating the track surface of the ball spline joint inner ring unit. . A ball spline joint inner ring that is heat treated by heating or cooling the inner ring unit, which consists of an inner ring formed with a plurality of tracks on the outer peripheral surface in contact with the ball bearing, and a sleeve that extends integrally from one end of the inner ring and has a shaft hole formed therein. In the heat treatment method of the unit,
Mounting the ball spline joint inner ring unit on a stand;
heating the track surface;
cooling the track surface;
Selectively heating the inner peripheral surface of the shaft hole formed in the sleeve; and
Cooling the inner peripheral surface of the shaft hole;
A heat treatment method for a ball spline joint inner ring unit comprising a. In claim 10,
The step of heating and cooling the track surface includes heating and cooling from one end to the other end of the inner ring of the ball spline joint inner ring unit,
The steps of heating and cooling the inner peripheral surface of the shaft hole include heating and cooling from one end to the other end of the sleeve of the ball spline joint inner ring unit,
The first area heat-treated in the step of heating the track surface and the second area heat-treated in the step of heating the inner peripheral surface of the shaft hole are arranged to overlap corresponding to the front and rear longitudinal directions of the inner ring,
A heat treatment method for a ball spline joint inner ring unit, characterized in that the first region and the second region are heat treated so that they do not meet each other within the thickness range of the inner ring. In claim 11,
The second area is,
A heat treatment method for a ball spline joint inner ring unit, characterized in that one end and the other end of the sleeve are spaced apart at a set interval inward along the longitudinal direction. In claim 10,
A heat treatment method for a ball spline joint inner ring unit, further comprising mounting an upper jig to cover the top of the shaft hole or at least a portion of the top side of the track surface before heating the track surface. In claim 10,
Smoke generated during the heat treatment or cooling process is removed in at least one or a plurality of steps among heating the track surface, cooling the track surface, heating the inner peripheral surface of the shaft hole, and cooling the inner peripheral surface of the shaft hole. A heat treatment method for a ball spline joint inner ring unit, further comprising a smoke discharge step.

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