Hardening apparatus and hardening method

Abstract

The present invention provides a quenching apparatus and quenching method that can suppress the occurrence of cracks during induction heating. [Solution] A heat treatment device for induction heating the inner circumferential surface of a constant velocity joint outer ring, comprising: heating coils positioned opposite to both ends of a roller guide portion extending in the axial direction of the inner circumferential surface and to both inclined portions adjacent to both ends of a projection that protrudes radially inward from both ends of the inner circumferential surface and extends axially along both ends, for induction heating of both ends and both inclined portions; a first injection unit for injecting coolant into the upper surface of the projection portion and the central part of the roller guide portion, which are provided axially along both inclined portions; a second injection unit for injecting coolant into the chamfered portions provided on the open end side of the inner circumferential surface on both inclined portions and the upper surface; a third injection unit for injecting coolant into the open end side of the inner circumferential surface on both inclined portions; a fourth injection unit for injecting coolant into the outer surface of the open end of the inner circumferential surface adjacent to both inclined portions and the chamfered portions; and a fifth injection unit for injecting coolant into the outer circumferential surface of the constant velocity joint outer ring.

Description

Technical Field

[0001] The present invention relates to a quenching device and a quenching method.

Background Art

[0002] Patent Document 1 discloses a heating coil used for induction heating of a roller guide groove formed on the inner peripheral surface inside an outer ring, which includes a coil body inserted into the outer ring through an opening on one end side of the outer ring of a tripod constant velocity joint, and a plurality of shield members arranged to face the inner peripheral surface of the opening side end of the outer ring (Claim 1). Instead of the shield member 111 of the heating coil 101, it includes a chamfer cooling jacket 211, and the chamfer cooling jacket 211 sprays a coolant onto the chamfer surface 5b of the convex portion 5 and the opening end surface 2a of the outer ring (Paragraph

[0042] ).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in an outer ring provided with a groove on the chamfer surface (chamfer portion), cracks may occur starting from the groove during induction heating. An object of the present invention is to provide a quenching device and a quenching method that can suppress the occurrence of cracks starting from the groove during induction heating even in an outer ring provided with a groove on the chamfer surface (chamfer portion).

Means for Solving the Problems

[0005] To solve the above problems, the present invention employs the following means. (1) A quenching apparatus for induction heating the inner circumferential surface of a constant velocity joint outer ring having an open end on one end in the axial direction, comprising: a heating coil inserted into the inner circumferential surface from the open end, positioned opposite to both ends in the axial direction of a roller guide portion extending in the axial direction of the inner circumferential surface and to both inclined portions adjacent to both ends of a projection that protrudes radially inward from both ends and extends axially along the ends, and which induction heats both ends and both inclined portions to a quenching temperature or above; and adjacent to the both inclined portions, A quenching apparatus comprising: a first injection unit that injects coolant into the upper surface of the protruding portion and the central part of the roller guide portion, which are provided in the axial direction along the inclined portion; a second injection unit that injects coolant into the chamfered portion provided on the open end side of the inner circumferential surface of both inclined portions and the upper surface portion; a third injection unit that injects coolant into the open end side of the inner circumferential surface of both inclined portions; a fourth injection unit that injects coolant into the outer surface of the open end of the inner circumferential surface adjacent to both inclined portions and the chamfered portion; and a fifth injection unit that injects coolant into the outer circumferential surface of the constant velocity joint outer ring.

[0006] (2) The quenching apparatus of (1), wherein the second injection unit, the third injection unit, and the fourth injection unit are composed of an integrated cooling jacket.

[0007] (3) The quenching apparatus of (1) or (2) wherein the induction heating of both ends of the roller guide portion of the heating coil is further provided with core portions that extend in the axial direction of the inner circumferential surface, thereby suppressing the induction heating of both ends to below the quenching temperature.

[0008] (4) A method for induction heating the inner circumferential surface of a constant velocity joint outer ring having an open end on one end in the axial direction, wherein a heating coil inserted into the inner circumferential surface from the open end is positioned opposite to both ends in the axial direction of a roller guide portion extending in the axial direction of the inner circumferential surface and to both inclined portions adjacent to both ends of a protruding portion that protrudes radially inward from both ends of the inner circumferential surface and extends along the axial direction along both ends, thereby inducing the heating of both ends and both inclined portions to a heat treatment temperature or above the heat treatment temperature A quenching method comprising: heating the material; spraying coolant onto the upper surface of the protrusions adjacent to the two inclined portions and provided axially along the two inclined portions and onto the central part of the roller guide portion; spraying coolant onto the chamfered portions provided on the open end side of the inner circumferential surface of the two inclined portions and the upper portion; spraying coolant onto the open end side of the inner circumferential surface of the two inclined portions; spraying coolant onto the outer surface of the open end of the inner circumferential surface adjacent to the two inclined portions and the chamfered portion; and spraying coolant onto the outer circumferential surface of the constant velocity joint outer ring.

[0009] (5) The quenching method of (4) wherein the induction heating of both ends of the roller guide portion of the heating coil is further provided with core portions that extend in the axial direction of the inner circumferential surface, thereby suppressing the induction heating of both ends to below the quenching temperature. [Effects of the Invention]

[0010] According to the present invention, a quenching apparatus and quenching method are provided that can suppress the occurrence of cracks originating from the grooves during induction heating, even in outer rings having grooves in the chamfered surface (chamfered portion). [Brief explanation of the drawing]

[0011] [Figure 1] This is a cross-sectional view showing an example of a constant velocity joint outer ring. [Figure 2] Figure 1 is a plan view of the outer ring of the constant velocity joint as seen from the open end side 1a. [Figure 3] Figure 1 is a plan view of the quenching apparatus used for quenching the outer ring of a constant velocity joint. [Figure 4]This is a schematic diagram showing the coolant injection state in the cross-section of the quenching apparatus shown in Figure 3, along line AA. [Figure 5] Figure 1 is a perspective view of the quenching apparatus used for quenching the outer ring of a constant velocity joint. [Figure 6] Figure 1 is a plan view of a quenching apparatus according to another embodiment used for quenching the outer ring of a constant velocity joint. [Figure 7] This is a perspective view of a quenching apparatus according to another embodiment used for quenching the outer ring of the constant velocity joint shown in Figure 1. [Modes for carrying out the invention]

[0012] Figures 1 and 2 show an example of a constant velocity joint outer ring (hereinafter referred to as "outer ring"). The outer ring 1 has an open end 1a on one end in the axial direction X. As shown in Figures 2 and 3, the inner circumferential surface 1aa of the outer ring 1 is provided with three roller guide portions 2 and three protrusions 3. The three roller guide portions 2 are arranged at 120° intervals in the circumferential direction C and extend from the open end 1a of the outer ring 1 in the axial direction X of the inner circumferential surface 1aa. The three protrusions 3 protrude radially inward from the inner circumferential surface 1aa and extend along the roller guide portions 2 between two adjacent roller guide portions 2 in the circumferential direction C, from the open end 1a of the outer ring 1 in the axial direction X.

[0013] Specifically, the three protrusions 3 project inward radially from each of the three roller guide portions 2 that extend in the axial direction X of the inner circumferential surface 1aa, from their respective axial ends 2a, 2b, and also extend in the axial direction X along their respective ends 2a, 2b.

[0014] More specifically, the three protrusions 3 are adjacent to both end portions 2a and 2b of the roller guide portion 2, extend in the axial direction X from the opening end portion 1a of the outer ring 1 along both end portions 2a and 2b, and are inclined in a direction protruding inward in the radial direction of the inner peripheral surface 1aa. Each includes both inclined portions 3b, 3b and an upper surface portion 3c that is adjacent to both inclined portions 3b, 3b in the axial direction X, extends in the axial direction X from the opening end portion 1a of the outer ring 1 along both inclined portions 3b, 3b, and protrudes inward in the radial direction of the inner peripheral surface 1aa.

[0015] When a roller (not shown) slides on both inclined portions 3b, 3b of the protrusion 3, the transmission distance (for example, the distance between the differential and the drive shaft) is changed. The inner peripheral surface 1aa of both inclined portions 3b, 3b that are in sliding contact with the roller is induction hardened, and the surface hardness of both inclined portions 3b, 3b is increased. In addition, for the outer ring 1 according to the present embodiment, the inner peripheral surface 1aa of both end portions 2a, 2b of the roller guide portion 2 adjacent to both inclined portions 3b, 3b is also induction hardened, and the surface hardness is increased.

[0016] However, chamfered surfaces (chamfered portions) 3a are provided on the opening end portion 1a side of the inner peripheral surface 1aa in both inclined portions 3b, 3b and the upper surface portion 3c of the protrusion 3. In the present embodiment, in addition to both end portions 2a, 2b of the roller guide portion 2 and the inner peripheral surface 1aa of both inclined portions 3b, 3b of the protrusion 3, the chamfered surfaces (chamfered portions) 3a and the outer surface 3aa of the opening end portion 1a of the inner peripheral surface 1aa adjacent to both inclined portions 3b, 3b and the chamfered surfaces (chamfered portions) 3a are regions that are not induction hardened (non-induction hardened regions). And, a protrusion 8 that bulges toward the inside of the roller guide portion 2 is formed in the non-induction hardened region of the outer surface 3aa. This protrusion 8 is formed, for example, by driving a pin or the like into the opening end portion 1a of the outer ring 1 along the outer surface 3aa and plastically deforming the material in the non-induction hardened region of the outer surface 3aa.

[0017] (Basic configuration of an induction hardening device for a constant velocity joint outer ring) Figs. 3 to 5 show an example of the basic configuration of the induction hardening device in the present embodiment. The quenching device 100 shown in FIGS. 3 and 4 is used for quenching the constant velocity joint outer ring 1 described above. The quenching device 100 is a quenching device that induction-heats the inner peripheral surface 1aa of the constant velocity joint outer ring 1 having an opening end 1a on one end side in the axial direction A, and includes a heating coil 101 inserted into the inner peripheral surface 1aa from the opening end 1a, a first injection part 102 that injects a coolant into the above-described non-quenched area (non-quenched area), a second injection part 103, third injection parts 104A and 104B, a fourth injection part 105, and a fifth injection part 106. The heating coil 101 is inserted into the inner peripheral surface 1aa of the outer ring 1 from the opening end 1a on one end side of the outer ring 1, and is disposed opposite to both end portions 2a and 2b of the roller guide portion 2 of the outer ring 1 and both inclined portions 3b and 3b of the protruding portion 3, and induction-heats both end portions 2a and 2b and both inclined portions 3b and 3b to the quenching temperature or a temperature equal to or higher than the quenching temperature.

[0018] The first injection part 102 injects a coolant onto the upper surface portion 3c of the protruding portion 3 and the central portion 2aa of the roller guide portion 2. By this injection, coolant is supplied to the inner peripheral surface 1aa of both end portions 2a and 2b of the roller guide portion 2 and both inclined portions 3b and 3b of the protruding portion 3 that are induction-heated by the heating coil 101, and both end portions 2a and 2b and both inclined portions 3b and 3b are rapidly cooled. As a result, the inner peripheral surface 1aa of both end portions 2a and 2b and both inclined portions 3b and 3b is quenched, and quenching of the upper surface portion 3c of the protruding portion 3 and the central portion 2aa of the roller guide portion 2 is prevented. It is preferable from the viewpoint of productivity that the quenching device 100 performs induction heating and rapid cooling (quenching) of both end portions 2a and 2b of the roller guide portion 2 and both inclined portions 3b and 3b of the protruding portion 3 in a state where the positional relationship between the heating coil 101 and the outer ring 1 is fixed.

[0019] The second injection part 103 injects a coolant onto the chamfered portion 3a provided on the opening end 1a side of the inner peripheral surface 1aa in both inclined portions 3b and 3b and the upper surface portion 3c of the protruding portion 3. This prevents quenching of the chamfered portion 3a.

[0020] The third injection parts 104A and 104B inject a coolant onto the opening end 1a side of the inner peripheral surface 1aa in both inclined portions 3b and 3b of the protruding portion 3. This prevents hardening of the open end 1a of the inner circumferential surface 1aa on both inclined portions 3b, 3b of the protruding portion 3. Furthermore, the open end 1a side of the inner circumferential surface 1aa on both inclined portions 3b, 3b of the protruding portion 3 is adjacent to the chamfered portion 3a in the positive direction (arrow direction) and negative direction (opposite direction of the arrow) of the circumferential direction C. Therefore, by spraying coolant onto the chamfered portion 3a with the second injection unit 103, and also by spraying coolant onto the areas on both sides of the circumferential direction C adjacent to the chamfered portion 3a with the third injection units 104A and 104B, hardening of the chamfered portion 3a is further prevented.

[0021] The fourth injection unit 105 injects coolant onto the outer surface 3aa of the open end 1a of the inner circumferential surface 1aa adjacent to both inclined portions 3b, 3b and the chamfered portion 3a of the protruding portion 3. This prevents hardening of the outer surface 3aa. Furthermore, cooling the outer surface 3aa of the open end 1a of the inner circumferential surface 1aa adjacent to the chamfered portion 3a further prevents hardening of the chamfered portion 3a. In addition, cooling the outer surface 3aa of the open end 1a of the inner circumferential surface 1aa adjacent to both inclined portions 3b, 3b of the protruding portion 3 also promotes cooling of the regions on both sides of the circumferential direction C adjacent to the chamfered portion 3a, further preventing hardening of the chamfered portion 3a.

[0022] The fifth injection unit 106 injects coolant onto the outer circumferential surface 1b of the outer ring 1. This prevents the hardened layer on the inner circumferential surface 1aa of both ends 2a, 2b and both inclined portions 3b, 3b from reaching the outer circumferential surface 1b (burnout of the outer ring 1). From the above, the hardening apparatus according to this embodiment can suppress the occurrence of cracks originating from the grooves during induction heating, even in outer rings with grooves provided on the chamfered surface (chamfered portion).

[0023] (Configuration of the heating coil) Figure 5 shows an example of a cooling jacket for cooling the heating coil and chamfered surface (beveled part) of the quenching apparatus in this embodiment. As described above, the heating coil 101 comprises a coil body 110 and a plurality of shielding members 111. The coil body 110 includes three heating sections 112A, 112B, and 112C positioned on the inside of the inner circumferential surface 1aa when inserted into the inner circumferential surface 1aa from the open end 1a at one end of the outer ring 1, and three connecting sections 113A, 113B, and 113C positioned on the outside of the inner circumferential surface 1aa. The heating sections 112A, 112B, and 112C are arranged at 120° intervals around the axial direction X of the coil body 110, and are positioned on the roller guide section 2 of the inner circumferential surface 1aa of the outer ring 1 when inserted into the inner circumferential surface 1aa of the outer ring 1.

[0024] The heating section 112A has a pair of first heating conductors 120 and second heating conductors 121. The first heating conductor 120 extends along the axial direction X and is positioned opposite one end 2a or 2b of the roller guide section 2 and one inclined portion 3b or 3b of the projection section 3 along the axial direction X. The second heating conductor 121 extends along the axial direction X and is positioned opposite the other end 2a or 2b of the roller guide section 2 and the other inclined portion 3b or 3b of the projection section 3 along the axial direction X.

[0025] In this configuration, the chamfered surface (beveled portion) 3a, which is an unhardened region (unhardened area), and the outer surface 3aa of the opening end 1a of the inner circumferential surface 1aa adjacent to the chamfered surface (beveled portion) 3a, which is an unhardened region, are not arranged with the pair of first heating conductors 120 and second heating conductors 121 facing each other, except for both ends 2a, 2b of the roller guide portion 2 and both inclined portions 3b, 3b of the protruding portion 3. Furthermore, the distance between the first heating conductor 120 and the second heating conductor 121 in these unhardened regions is greater than the distance between the opposing ends 2a, 2b of the roller guide portion 2 and the two inclined portions 3b, 3b of the protruding portion 3, which are hardened regions. With this arrangement, the output of the high-frequency current supplied to the coil body 110 is controlled to keep the hardened region at or above the hardening temperature, and the unhardened region below the hardening temperature. This arrangement is the same for heating sections 112B and 112C, so the explanation is omitted.

[0026] The tip of the first heating conductor 120 and the tip of the second heating conductor 121, which are located on the bottom side opposite the open end 1a of the outer ring 1, are connected via a bridge heating conductor 122, and the heating section 112A is formed in a U-shape overall. Heating sections 112B and 112C also have a first heating conductor 120, a second heating conductor 121, and a bridge heating conductor 122, and are formed in a U-shape overall, similar to heating section 112A.

[0027] The connection section 113A has a pair of first connecting conductors 123 and second connecting conductors 124. The first connecting conductor 123 extends along the axial direction X from the second heating conductor 121 of the heating section 112A via a stepped portion S provided in the circumferential direction C where the distance between the second heating conductor 121 and the first heating conductor 120 of the heating section 112A in the circumferential direction C narrows. The second connecting conductor 124 extends along the axial direction X from the first heating conductor 120 of the heating section 112B via a stepped portion S provided in the circumferential direction C where the distance between the first heating conductor 120 and the second heating conductor 121 of the heating section 112B in the circumferential direction C narrows. The tip of the first connecting conductor 123 opposite to the open end 1a of the outer ring 1 and the tip of the second connecting conductor 124 opposite to the open end 1a of the outer ring 1 are connected via a bridge connecting conductor 125, and the connection section 113A is formed in a U shape as a whole. The connection section 113A connects two adjacent heating sections 112A and 112B in series along the circumferential direction C.

[0028] The connection section 113B has a pair of first connecting conductors 123 and second connecting conductors 124. The first connecting conductor 123 extends along the axial direction X from the second heating conductor 121 of the heating section 112B via a stepped portion S provided in the circumferential direction C where the distance between the second heating conductor 121 and the first heating conductor 120 of the heating section 112B in the circumferential direction C narrows. The second connecting conductor 124 extends along the axial direction X from the first heating conductor 120 of the heating section 112C via a stepped portion S provided in the circumferential direction C where the distance between the first heating conductor 120 and the second heating conductor 121 of the heating section 112C narrows. The end of the first connecting conductor 123 opposite to the open end 1a of the outer ring 1 and the end of the second connecting conductor 124 opposite to the open end 1a of the outer ring 1 are connected via a bridge connecting conductor 125, and the connection portion 113B is formed in a U-shape overall, similar to the connection portion 113A. The connection portion 113B connects two adjacent heating portions 112B and 112C in series in the circumferential direction.

[0029] The connection section 113C has a pair of first connecting conductors 123 and second connecting conductors 124. The first connecting conductor 123 extends along the axial direction X from the second heating conductor 121 of the heating section 112C via a stepped portion S provided in the circumferential direction C where the distance between the second heating conductor 121 and the first heating conductor 120 of the heating section 112C in the circumferential direction C narrows. The second connecting conductor 124 extends along the axial direction X from the first heating conductor 120 of the heating section 112A via a stepped portion S provided in the circumferential direction C where the distance between the first heating conductor 120 and the second heating conductor 121 of the heating section 112A narrows. The first connecting conductor 123 and the second connecting conductor 124 of the connection section 113C are connected to a power supply (not shown), and the heating sections 112A, 112B, and 112C are connected in series to the power supply via the connection sections 113A, 113B, and 113C. By arranging the heating sections 112A, 112B, and 112C of the heating coil 101 on the inner circumferential surface 1aa of the roller guide section 2 of the outer ring 1, the first heating conductor 120 and the second heating conductor 121 of the heating sections 112A, 112B, and 112C can be positioned opposite each other along the extending direction of the ends 2a, 2b and the inclined sections 3b, 3b of the protruding section 3.

[0030] When a high-frequency current is supplied from the power supply to the coil body 110, an induced current I flows on the inner circumferential surface 1aa of the outer ring 1. The induced current I basically flows along the first heating conductor 120 and the second heating conductor 121 and the bridge heating conductor 122 of the heating sections 112A, 112B, and 112C, respectively, and flows along both ends 2a and 2b of the roller guide section 2 in the direction of extension of the roller guide section 2, as well as along both inclined portions 3b and 3b of the protruding section 3 in the direction of extension of the protruding section 3. The induced current I then flows from the end 2a (or end 2b) of the roller guide section 2 to the end 2b (or end 2a) of the adjacent roller guide section 2 that straddles the protruding section 3 in the circumferential direction, across the surface of the protruding section 3.

[0031] The conductor groups (first heating conductor 120, second heating conductor 121, bridge heating conductor 122, first connecting conductor 123, second connecting conductor 124, and bridge connecting conductor 125) forming the heating sections 112A, 112B, 112C and the connecting sections 113A, 113B, 113C are made of tubular material and form a continuous internal flow path 126. A cooling liquid such as water flows through the internal flow path 126. The coil body 110, which generates heat when energized, is cooled by the cooling liquid flowing through the internal flow path 126.

[0032] (Structure and arrangement of shielding components and cooling jacket) Shield members 111 are provided for each connection section 113A, 113B, and 113C, and are positioned between the first connecting conductor 123 and the second connecting conductor 124 of each heating section (in Figure 5, only the section between the first connecting conductor 123 and the second connecting conductor 124 of connection section 113A is shown (others are omitted)). The first heating conductor 120 and the second heating conductor 121 of each heating section 112A, 112B, and 112C are shorter than the length in the axial direction X and the width in the circumferential direction C of the roller guide section 2 of the outer ring 1, and are housed on the inner circumferential surface 1aa of the roller guide section 2. Therefore, the shield members 111 (second cooling liquid injection section 103) positioned on the end side of the open end 1a of the first connecting conductor 123 and the second connecting conductor 124 are housed on the inner circumferential surface 1aa side of the open end 1a of the outer ring 1, and are positioned opposite the chamfered surface 3a of the protruding section 3. Furthermore, as shown in Figure 5, a shield member 111 is positioned between the third coolant injection sections 104A and 104B. The front surface of the shield member 111 is provided with holes for injecting the coolant.

[0033] As described above, a stepped portion S is provided between the first heating conductor 120 and the second heating conductor 121 of the heating sections 112A, 112B, and 112C, and the first connecting conductor 123 and the second connecting conductor 124 of the connecting sections 113A, 113B, and 113C. As shown in Figure 5, the third coolant injection sections 104A and 104B are positioned at the stepped section S between the second heating conductor 121 of the heating section 112A and the first connecting conductor 123 of the connecting section 113A, and at the stepped section S between the first heating conductor 120 of the heating section 112B and the second connecting conductor 124 of the connecting section 113A, respectively. The front surfaces of the third coolant injection sections 104A and 104B are provided with holes for injecting the coolant.

[0034] The third coolant injection sections 104A and 104B, and the shield member 111 (second coolant injection section 103) located between the third coolant injection sections 104A and 104B, are mounted on a support 114. The support 114 is provided with a channel for supplying a coolant such as water. Furthermore, the upper surface of the support 114 is provided with multiple holes for injecting coolant, forming a fourth coolant injection section 105. The support 114 is provided with a coolant supply port 114a, which is connected to the holes for injecting coolant in the shield member 111 (second coolant injection section 103), the third injection sections 104A and 104B, and the fourth injection section 105, respectively, through an internal flow path 126 (not shown). In other words, in the quenching apparatus of this embodiment, the second injection unit 103, the third injection units 104A, 104B, and the fourth injection unit 105 are composed of an integrated cooling jacket. This configuration reduces the number of means required to supply the coolant.

[0035] In this embodiment, the shield member 111 and water-cooling jacket (second injection section 103, third injection sections 104A, 104B, and fourth injection section 105) described above are also placed between the stepped section S of the connection section 113B that contacts the heating section 112B and the stepped section S of the connection section 113B that contacts the heating section 112C, and between the stepped section S of the connection section 113C that contacts the heating section 112A and the stepped section S of the connection section 113C that contacts the heating section 112C.

[0036] Furthermore, the coil body 110 is fixed to the support 114. The support 114 is made of an insulating material such as ceramics. In this embodiment, in which induction heating and rapid cooling are performed on both ends 2a, 2b of the roller guide portion 2 and both inclined portions 3b, 3b of the protruding portion 3 while the positional relationship between the heating coil 101 and the outer ring 1 is fixed, the support 114 further supports the outer ring 1. That is, the outer ring 1 is supported such that the outer surface 3aa of the open end 1a of the inner circumferential surface 1aa adjacent to both inclined portions 3b, 3b and the chamfered portion 3a of the outer ring 1 is aligned with a plurality of holes (fourth injection portion 105 of the coolant) provided on the upper surface of the support 114 for injecting coolant (see Figure 3). In this configuration, the second injection unit 103 is positioned to inject coolant onto the chamfered portion 3a of the inner circumferential surface 1aa, and the third injection units 104A and 104B are positioned to inject coolant onto the open end 1a side of the inner circumferential surface 1aa on both inclined portions 3b, 3b (see Figure 3).

[0037] The first injection unit 102 is composed of a cooling jacket that extends in the axial direction X and is located inside the heating units 112A, 112B, 112C and connecting units 113A, 113B, 113C that constitute the coil body 110. It is provided with holes for injecting cooling liquid in the axial direction X so as to inject cooling liquid in the axial direction X to the upper surface 3C of the protruding unit 3 and the central part 2aa of the roller guide unit 2 (not shown). The fifth injection unit 102 is composed of a cooling jacket positioned around the outer periphery of the outer circumferential surface 1b of the outer ring 1 when the heating coil 101 is inserted into the inner circumferential surface 1aa. The inner circumferential side of the cooling jacket is provided with holes (not shown) for injecting coolant onto the outer circumferential surface 1b of the outer ring 1.

[0038] Next, a quenching apparatus according to another embodiment of the present invention will be described. In another embodiment of the present invention, as shown in Figures 6 and 7, a quenching apparatus is further provided with a core portion 150 extending in the axial direction X of the inner circumferential surface 1aa on both ends 2a and 2b of the roller guide portion 2 in the heating coil 101. Other aspects are the same as those of the embodiments described above, and therefore will not be explained further. In this way, by providing the core portion 150, the magnetic flux to both ends 2a and 2b of the roller guide portion 2 of the heating coil is suppressed, and the magnetic flux is concentrated on both inclined portions 3b, 3b of the protruding portion 3. Therefore, the induction heating of both ends 2a and 2b of the roller guide portion 2 can be suppressed to below the quenching temperature, and thus quenching of both ends 2a and 2b can be suppressed.

[0039] Next, the quenching method according to the present invention will be described. The quenching method according to this embodiment is a quenching method for induction heating the inner circumferential surface 1aa of a constant velocity joint outer ring 1 having an open end 1a on one end in the axial direction X, wherein a heating coil 101 inserted from the open end 1a to the inner circumferential surface 1aa is positioned opposite to both ends 2a, 2b of a roller guide portion 2 extending in the axial direction X of the inner circumferential surface 1aa in the axial direction X, and to both inclined portions 3b, 3b adjacent to both ends 2a, 2b of a projection portion 3 that protrudes radially inward from both ends 2a, 2b and extends in the axial direction X along the ends 2a, 2b, and the ends 2a, 2b and the both inclined portions 3b, 3b are heated to a quenching temperature or The material is induction heated to a temperature above the quenching temperature, and coolant is sprayed onto the upper surface 3C of the protruding portion 3 and the central portion 2aa of the roller guide portion 2, which are adjacent to the two inclined portions 3b, 3b and provided along the two inclined portions 3b, 3b in the axial direction X. Coolant is also sprayed onto the chamfered portion 3a provided on the open end 1a side of the inner circumferential surface 1aa on the two inclined portions 3b, 3b and the upper surface 3c. Coolant is also sprayed onto the open end 1a side of the inner circumferential surface 1aa on the two inclined portions 3b, 3b, and the outer surface 3aa of the open end 1a of the inner circumferential surface 1aa adjacent to the two inclined portions 3b, 3b and the chamfered portion 3a. Coolant is also sprayed onto the outer circumferential surface 1b of the constant velocity joint outer ring 1. The quenching method according to this embodiment can be carried out using the quenching apparatus shown in Figures 3 to 5.

[0040] In other words, as described above, in the quenching apparatus according to this embodiment, coolant is sprayed onto the upper surface 3c of the protruding portion 3 and the central portion 2aa of the roller guide portion 2, so that coolant can be supplied to the inner circumferential surfaces 1aa of both ends 2a, 2b of the roller guide portion 2 and both inclined portions 3b, 3b of the protruding portion 3, and that it can be rapidly cooled. As a result, the inner circumferential surfaces 1aa of both ends 2a, 2b and both inclined portions 3b, 3b are quenched, while quenching of the upper surface 3c of the protruding portion 3 and the central portion 2aa of the roller guide portion 2 is prevented. Furthermore, coolant is sprayed onto the chamfered portion 3a provided on the open end 1a side of the inner circumferential surface 1aa of both inclined portions 3b, 3b and the upper surface 3c of the protruding portion 3, thus preventing quenching of the chamfered portion 3a. In addition, coolant is sprayed onto the open end 1a side of the inner circumferential surface 1aa of both inclined portions 3b, 3b of the protruding portion 3, thus preventing quenching of the open end 1a. Furthermore, the open end 1a side of the inner circumferential surface 1aa on both inclined portions 3b, 3b of the protruding portion 3 is adjacent to the chamfered portion 3a in the positive direction (arrow direction) and negative direction (opposite direction of the arrow) of the circumferential direction C. Therefore, by spraying coolant onto the chamfered portion 3a and also spraying coolant onto the areas on both sides of the circumferential direction C adjacent to the chamfered portion 3a, hardening of the chamfered portion 3a is further prevented. Additionally, by spraying coolant onto the outer surface 3aa of the open end 1a of the inner circumferential surface 1aa adjacent to both inclined portions 3b, 3b of the protruding portion 3 and the chamfered portion 3a, hardening of the outer surface 3aa is prevented. Furthermore, by cooling the outer surface 3aa of the open end 1a of the inner circumferential surface 1aa adjacent to the chamfered portion 3a, hardening of the chamfered portion 3a is further prevented. In addition, by cooling the outer surface 3aa of the open end 1a of the inner circumferential surface 1aa adjacent to both inclined portions 3b, 3b of the protruding portion 3, the cooling of the regions on both sides in the circumferential direction C adjacent to the chamfered portion 3a is also promoted, further preventing hardening of the chamfered portion 3a. Furthermore, a cooling liquid is sprayed onto the outer circumferential surface 1b of the outer ring 1. This prevents the hardened layer on the inner circumferential surface 1aa of both ends 2a, 2b and both inclined portions 3b, 3b from reaching the outer circumferential surface 1b side (hardening of the outer ring 1). From the above, the quenching method according to this embodiment can suppress the occurrence of cracks originating from the grooves during induction heating, even in outer rings with grooves provided on the chamfered surface (chamfered portion).

[0041] In the quenching method according to this embodiment, a core portion 150 extending in the axial direction X of the inner circumferential surface 1aa is further provided on both ends 2a, 2b of the roller guide portion 2 in the heating coil 101, thereby suppressing induction heating at both ends to below the quenching temperature. The quenching method according to this embodiment can be carried out using the quenching apparatus shown in Figures 6 and 7. [Industrial applicability]

[0042] The hardening apparatus of the present invention can be used effectively in the field of hardening technology because, when hardening the inclined surfaces of both ends and protrusions of the roller guide portion formed on the inner circumferential surface of the outer ring of a tripod-type constant velocity joint, it can harden the chamfered surface (chamfered portion) 3a without causing cracks, even if there are grooves in the chamfered surface (chamfered portion) 3a. [Explanation of symbols]

[0043] 1. Constant velocity joint outer ring 1a Open end of the outer ring 1aa Inner surface of the outer ring 1b Outer surface of the outer ring 2 Roller guide section 2a, 2b Both ends of the roller guide section 2aa Central part of the roller guide section 3 Protrusion 3a Chamfered surface (beveled edge) 3aa External surface of the open end 3b, 3b Both inclined parts of the protruding section 3c Top part 100 Hardening equipment 101 Heating coil 102 First injection section of coolant 103 Second injection section of coolant 104A, 104B Third injection section of coolant 105 Coolant fourth injection section 106 Fifth injection section of the coolant 110 Coil Body 111 Shielding member 112A,112B,112C Heating part 113A, 113B, 113C connection section 114 Support 120 First heating conductor 121 Second heating conductor 122 Bridge heating conductor 123 First connecting conductor 124 Second connecting conductor 125 Bridge-connected conductor 126 Internal flow path 150 Core section

Claims

1. A heat treatment apparatus for induction heating the inner circumferential surface of a constant velocity joint outer ring having an open end on one end in the axial direction, A heating coil is inserted into the inner circumferential surface from the open end and is positioned opposite to both axial ends of a roller guide portion that extends in the axial direction of the inner circumferential surface, and to both inclined portions adjacent to both ends of a protruding portion that projects radially inward from both ends of the inner circumferential surface and extends axially along both ends, and which induces heating of both ends and both inclined portions to the quenching temperature or above. A first injection unit is provided adjacent to the two inclined portions and along the two inclined portions in the axial direction, which sprays coolant onto the upper surface of the protrusion and the central part of the roller guide portion. A second injection unit that sprays coolant onto the chamfered portion provided on the opening end side of the inner circumferential surface of both inclined portions and the upper surface portion, A third injection unit that injects coolant into the open end side of the inner circumferential surface of both inclined portions, A fourth injection unit that sprays coolant onto the outer surface of the opening end of the inner circumferential surface adjacent to both inclined portions and the chamfered portion, A fifth injection unit that sprays coolant onto the outer circumferential surface of the constant velocity joint outer ring, A quenching apparatus equipped with the following features.

2. The quenching apparatus according to claim 1, wherein the second injection unit, the third injection unit, and the fourth injection unit are composed of an integrated cooling jacket.

3. The quenching apparatus according to claim 1 or 2, wherein the induction heating of both ends of the roller guide portion in the heating coil is further provided with core portions extending in the axial direction of the inner circumferential surface, thereby suppressing the induction heating of both ends to a temperature below the quenching temperature.

4. A method for induction heating the inner circumferential surface of a constant velocity joint outer ring having an open end on one end in the axial direction, The heating coil inserted into the inner circumferential surface from the opening end is positioned opposite to both axial ends of the roller guide portion extending in the axial direction of the inner circumferential surface and to the two inclined portions adjacent to the ends of the protruding portion that extends radially inward from both ends of the inner circumferential surface and along the axial direction of the ends, and the ends and the two inclined portions are inductively heated to or above the quenching temperature. Cooling liquid is sprayed onto the upper surface of the protruding portion and the central part of the roller guide portion, which are adjacent to the two inclined portions and provided in the axial direction along the two inclined portions. Cooling liquid is sprayed onto the chamfered portion provided on the open end side of the inner circumferential surface of both inclined portions and the upper portion. Cooling liquid is sprayed onto the open end side of the inner circumferential surface in both of the aforementioned inclined portions. Cooling liquid is sprayed onto the outer surface of the opening end of the inner circumferential surface adjacent to both inclined portions and the chamfered portion. Coolant is sprayed onto the outer surface of the constant velocity joint outer ring. Hardening method.

5. The quenching method according to claim 4, wherein the induction heating of both ends of the roller guide portion of the heating coil is further provided with core portions extending in the axial direction of the inner circumferential surface, thereby suppressing the induction heating of both ends to a temperature below the quenching temperature.

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