JPH057232Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a heat treatment jig for suppressing the occurrence of distortion of internal teeth during heat treatment, especially of thin-walled precision parts with internal teeth formed thereon. be.

[Conventional technology]

When quenching a thin precision part, for example, the outer peripheral part 1a of the synchronizing mesh ring 1 of an automobile transmission as shown in FIGS. To prevent this, jigs as shown in FIGS. 6 to 8 are used. That is, the jig shown in FIG. 6 includes an outer diameter part 2a that fits into the inner diameter part (tooth tip inner diameter) 1b of the synchronized meshing ring (hereinafter referred to as the workpiece) 1,
A plug 2 is attached to a vertically movable plunger P of a heat treatment machine (quenching machine), and a lower plate is attached to a support ring 3 provided on the top surface of a bed B of the machine, and has a hole 4a through which the plug 2 passes. 4, and after setting the jig with the above configuration into the quenching machine, place the workpiece heated to a predetermined temperature at a predetermined position on the lower die plate 4,
First, the plunger P is raised, and the outer diameter part 2a of the plug 2 attached thereto is fitted into the inner diameter part 1b of the workpiece 1. Next, the upper surface 1d of the plug is pressed with the upper die U, and this state is Then, quenching oil is poured into the outer peripheral portion 1a to perform quenching (oil quenching).

By using the above jig, it is possible to prevent heat treatment distortions such as tapering and dulling of the inner diameter portion 1b of the workpiece 1.

Moreover, what is shown in FIGS. 7 and 8 is a heat treatment jig according to Utility Application No. 149919/1989, which was previously filed by the applicant of the present invention, and is a jig that fits into the inner diameter part 1b of the workpiece 1. A plug 5 which is equipped with an outer diameter portion 5a and which is attached to a vertically movable plunger P of a heat treatment machine;
is integrally fixed to the lower end of the plug outer portion 5.
a and a keyway 6 on the outer periphery.
A lower die plate 6 formed with a shape B and a hole 3 supported by the bed B of the machine and through which the plate 6 passes.
The support ring 3 has a hole 3a provided with a key 7 that fits into the keyway 6b.

After setting the jig with the above configuration into a heat treatment machine (quenching machine), the workpiece 1 heated to a predetermined temperature is lightly fitted onto the upper end of the outer diameter portion 5a of the plug 5, and the upper die U of the machine is placed. When lowered, the end surface 1d becomes the upper side of the workpiece 1 at the lower end of the upper mold U.
and press its inner diameter part 1b to the outer diameter part 5 of the plug 5.
The work piece 1 is pressed down while strongly fitting into the mold plate 6, and the lower end surface 1c of the work piece 1 is finally brought into contact with the upper surface 6a of the lower die plate 6.

In this state, the heat treatment machine processes the workpiece 1.
When the outer circumferential portion 1a of the workpiece 1 is hardened (oil hardened), the perpendicularity between the end surface 1c and the inner diameter portion 1d of the workpiece 1 is accurately maintained.

[Problem that the invention attempts to solve]

In all of the above conventional technologies, since the outer diameter part 2a of the plug 2 fits into the inner diameter part 1b of the workpiece, the dimensional accuracy of the between pin diameter after hardening can be ensured, but the machining before hardening is The problem is that the distortion of the tooth profile due to the above-mentioned process is performed separately from the tooth profile, or the tooth profile is deformed by fitting into the inner diameter portion 1b of the plug 2, resulting in large variations in the tooth surface accuracy of the internal teeth. There is.

11 and 12 show the internal teeth 4 of the workpiece before and after hardening using the conventional plug 2.
This is a diagram showing the error in the pressure angle on the tooth surface at different locations (from Figure 3: at 90° intervals). There are variations, and the above 4
At some points, the values are large on both the right tooth flank and the left tooth flank.
It is also clear that there are large variations.

In view of the above, the purpose of the present invention is to prevent distortion of internal teeth during heat treatment, and to correct variations in pressure angle error during machining, especially for thin precision parts that are easily deformed by heat treatment. It was devised as

[Means for solving problems]

The present invention will be explained with reference to FIGS. 1 to 5 and FIGS. 9 and 10, which correspond to embodiments. The jig of the present invention fits into the internal teeth 1f of the workpiece 1 on which the internal teeth 1f are formed. A plug 50 equipped with a matching toothed portion 50a and attached to a vertically movable plunger P of a heat treatment machine.
and a lower die plate 60 which is mounted on the support ring 3 provided on the machine and has a hole 60b through which the plug 50 passes.

"Function" After setting the jig with the above configuration in a heat treatment machine (quenching machine), the internal teeth 1f of the workpiece 1 heated to a predetermined temperature are inserted into the tooth profile 50 of the plug 50.
When the upper end of a is lightly fitted and the upper mold U of the machine is lowered, the lower end of the upper mold U presses the end surface 1d which is on the upper side of the workpiece 1, and the inner teeth 1f of the tooth shaped plug 50 are pressed. The workpiece 1 is pressed down while being firmly fitted into the tooth profile 50a of the workpiece 1, and the lower end surface 1c of the workpiece 1 is brought into contact with the upper surface 60a of the lower die plate 60.

In this state, the workpiece 1 is processed by the heat treatment machine.
If the outer peripheral portion 1a of the work piece 1 is hardened (oil hardened), the hardening is performed while the tooth surface shape of the internal tooth 1f of the workpiece 1 is accurately maintained.

When the hardening is completed, first, the vertically movable plunger P is operated downward, and the toothed plug 50 and the hole 60b of the lower die plate 60 are moved downward.
As a result, the tooth shaped plug 50 comes off from the inner teeth 1f of the workpiece 1, so the upper die U is raised,
All you have to do is take out the workpiece 1.

〔Example〕

Examples of the present invention are shown in FIGS. 1 to 5 and 9.
To explain with reference to Figs. 1 and 10, numeral 1 is a synchronous engagement ring often used in automobile transmissions shown as an example of a workpiece, and a shift fork (not shown) is fitted to the outer peripheral portion 1a. A groove 1e for sliding (rotation sliding) is formed, and an internal spline 1f is formed in the inner diameter portion 1b.

The most important thing about this part is improving the tooth profile accuracy of the internal tooth 1f.
The meshing and sliding of the external tooth member (spline shaft) fitted with f is performed smoothly, noise is reduced, and durability is increased. However, since the above-mentioned parts are thin parts, the above-mentioned deformation is likely to occur during heat treatment.

Reference numeral 50 denotes a toothed plug that is equipped with a toothed portion 5a that fits into the internal teeth 1f of the workpiece 1 and is attached to the vertically movable plunger P of the heat treatment machine;
The tooth profile is accurately formed so as to closely fit the left and right tooth flanks of the internal teeth 1f of the workpiece 1.

A lower die plate 60 has a hole 60b through which the plug 50 passes, and is mounted on the support ring 3, which will be described later. What is important is that the upper surface 60a of the lower mold plate 6 and the outer diameter portion 5a of the plug 5
and should be formed at exactly right angles.

Reference numeral 3 denotes a support ring, which is provided with a hole 3a through which the plug 50 passes, is relatively thick, and is mounted so as to be mostly embedded in the bed B of the heat treatment machine. The support ring 3 has its upper and lower surfaces 3
It is necessary to maintain the perpendicularity between b, 3c and the circumferential surface 3d.

After the jig of the present invention constructed as described above is set in a heat treatment machine as shown in the figure, the vertically movable plunger P is operated upward, and the workpiece 1 is lightly placed on the upper end of the toothed part 50a of the toothed plug 50. When the upper mold U of the heat treatment machine (quenching machine) is lowered, the lower end of the upper mold U presses the upper end surface 1d of the workpiece 1, and the inner teeth 1f of the plug 50 are pressed. The workpiece 1 is pushed down while tightly fitting into the toothed part 50a, and the lower end surface 1c of the workpiece 1 is brought into contact with the upper surface 60a of the lower die plate 60.

In this state, the workpiece 1 is processed by the heat treatment machine.
When the outer circumferential portion 1a of the workpiece 1 is hardened (oil hardened), the hardening is performed in a state in which the shape of the tooth surface of the workpiece 1, especially the internal teeth 1f, is accurately maintained.

When the hardening is finished, move the vertical plunger P.
When the preg 5 is moved downward, the preg 5 moves to the lower die plate 6.
It passes through the hole 60b of No. 0 and the hole 3a of the support ring 3, moves downward, contacts the bed B, and stops.
As a result, the tooth profile preg 50 comes off from the inner teeth 1f of the workpiece 1, so the upper die U is raised,
The workpiece 1 can be taken out.

By the way, when we look at the pressure angle errors on the tooth surfaces of the four internal teeth of the workpiece before and after quenching (Fig. 3~) using the jig of the present invention, Fig. 9 and 1.
As shown in Fig. 0, apart from the error shown in Fig. 9 before quenching, the error after quenching is as shown in Fig. 10 above.
At certain points, the numerical values are very small on both the right tooth flank and the left tooth flank, and the variation is also small. Compared to the pressure angle error caused by a conventional plug (Fig. 12), the angle numerical value is a fraction to a tenth. It became.

Attached Table 1 shows a comparison of the effects of hardening an example of the workpiece using a conventional jig and hardening using the jig of the present invention.

[Effect of idea]

The heat treatment jig of the present invention includes a tooth-shaped part that fits into the internal teeth of a workpiece on which internal teeth are formed, and a tooth-shaped plug attached to a vertically movable plunger of a heat treatment machine, and a tooth-shaped plug installed in the machine. The lower die plate is mounted on a support ring with a hole through which the plug passes, so that the inner teeth of the workpiece are connected to the inner teeth of the workpiece by means of the tooth-shaped plug, which has tooth-shaped portions that fit into the inner teeth of the workpiece. By simply fitting tightly into the tooth profile of the plug and pressing the lower end surface of the workpiece against the upper surface of the lower die plate, the accuracy of the tooth profile of the internal teeth of the workpiece can be accurately forced or maintained. It is possible to prevent distortion of the tooth profile of the workpiece due to hardening. Therefore, the meshing and sliding between the internal teeth of the workpiece and the mating external tooth member are performed smoothly, and noise is reduced.
This has the effect of increasing durability.

[Brief explanation of drawings]

Figure 1 is a longitudinal sectional view of the heat treatment jig of the present invention, Figure 2
The figures are a cross-sectional view taken along line A-A in Figure 1, a top view of the workpiece, Figure 4 is a longitudinal cross-sectional view of the workpiece, and Figure 5 is a cross-sectional view of the workpiece.
An enlarged view of part B in the figure, FIGS. 6 and 7 are vertical cross-sectional views showing conventional heat treatment jigs, and FIG.
The cross-sectional view taken along the line C-C in the figure, and FIGS. 9 to 12 show the pressure angle error of the internal teeth of the workpiece.
Figures 1 and 10 show the pressure angle errors before and after quenching of the workpiece according to the present invention, and Figs. 11 and 12 show the pressure angle errors before and after quenching of the workpiece using the conventional jig. FIG. 1... Workpiece, 1a... Same outer periphery, 1b...
Same inner diameter part, 1c, 1d... Same end surface, 1e... Same groove, 1f... Internal teeth, 2, 5... Plug, 2a...
Plug, 2a... same outer diameter part, 3... support ring,
4, 6, 60...Lower die plate, 50...Tooth shaped plug, 50a...Tooth shaped portion, P...Vertical movement plunger, U...Upper die, B...Bed.

【table】

Claims (1)

[Scope of utility model registration request] A tooth-shaped plug is provided with a tooth-shaped portion that fits into the internal teeth of a workpiece formed with internal teeth, and is attached to a vertically movable plunger of a heat treatment machine, and a tooth-shaped plug is attached to a support ring provided on the machine and the plug passes through. A heat treatment jig consisting of a lower mold plate with holes.