JPS582568B2 - Heat treatment distortion correction method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method and apparatus that can easily correct heat treatment distortions that are predicted to occur in a workpiece during heat treatment and heat treatment distortions that actually occur in the workpiece during heat treatment, regardless of the shape of the workpiece. Regarding.

When heat treatment such as carburizing and quenching is applied to a workpiece that has been cut into a predetermined shape after forging, heat treatment distortion occurs to a greater or lesser extent in the workpiece.

The amount and direction of heat treatment strain vary depending on the shape of the workpiece and heat treatment conditions, but for example, if the workpiece is an automobile differential side gear (hereinafter simply referred to as gear) 1 as shown in Figure 1, the strain will be distorted by the two-dot chain line in the figure. As shown, the end of the boss portion 2 is deformed inward.

A spline hole 3 is formed on the inner circumferential surface of the gear 1, but when the end of the boss portion 2 deforms as described above, the diameter of this portion of the spline hole 3 becomes smaller than other portions, and the gear It becomes difficult or impossible to fit the spline shaft of the rear axle shaft, which is the mating partner of -1, into the spline hole 3.

However, it is not easy to perform cutting or grinding to increase the diameter of the spline hole 3 that has been deformed due to heat treatment strain.

In addition, we use a pressurizing device that can control the magnitude of the pressurizing force,
Although it is possible to correct the heat treatment distortion by plastic deformation, if there are variations in the hardness of the workpieces, the state of correction of the heat treatment distortion will differ depending on the individual workpieces, and this has the disadvantage that the correction accuracy is not sufficient.

Furthermore, it is possible to correct heat treatment distortion by regulating the stroke of the press ram to apply pressure, but if there are variations in the dimensions of the workpiece, distortion correction ends after the distortion correction tool comes into contact with the workpiece. It is necessary to accurately regulate the stroke of the press ram until the stroke of the press ram is reached, and detection means and control means are required for this purpose, which leaves the problem that the entire apparatus becomes expensive.

With this background in mind, the present invention has been developed to ensure that even if the shape of the workpiece is difficult or impossible to correct for heat treatment distortion due to cutting or grinding, or even if there are variations in the hardness or dimensions of the workpiece, The object of this invention is to provide a method and apparatus capable of correcting heat treatment distortion of a workpiece so that the workpiece has a desired shape.

However, the feature of the heat treatment strain compensation method according to the present invention is that a strain compensation tool, which is held movable in the axial direction within a limited range, is pressed by the workpiece itself before or after heat treatment, so that the distortion compensation tool within the range is The workpiece is moved to one end, and while the workpiece is rigidly supported, pressure is applied to the distortion correction tool to move the distortion correction tool to the other end of the range, thereby removing the workpiece by an amount corresponding to this range. The purpose is to cause plastic deformation.

In this way, unlike the method of controlling the magnitude of the pressing force or the method of regulating the stroke of the press ram described above, even if there are variations in the hardness or dimensions of the workpiece, the workpiece can be Heat treatment distortion will be reliably corrected.

Further, the feature of the heat treatment distortion correction device according to the present invention is that it includes a main body of the device, a wedge body that is provided with an inclined surface and is movable on the main body of the device in the direction of inclination of the inclined surface, and a wedge body that has the inclined surface of the wedge body at one end. a support surface for supporting the workpiece on the opposite side of the inclined surface; a member, and a retaining portion having a shape corresponding to the shape of a portion of the workpiece in which heat treatment distortion is to be corrected on the side of the pressure receiving member opposite to the support surface, and the apparatus main body is provided with a retaining portion having a shape corresponding to the shape of a portion of the workpiece where heat treatment distortion is to be corrected, The present invention includes a distortion correction tool held movably by a certain stroke in the same direction, and a press device that presses the distortion correction tool in a direction toward the support surface of the pressure receiving member.

In this way, it becomes possible to carry out the method using a device that is simple in structure and inexpensive.

EMBODIMENT OF THE INVENTION Hereinafter, the heat treatment distortion correction method and apparatus according to the present invention will be described in further detail based on the drawings showing one embodiment thereof.

In the hardening distortion correction device 50 shown in FIG. 2, the device main body 10 includes three upper, middle, and lower support portions 11, 21, and 31 whose upper surfaces 12, 22, and 32 are flat surfaces, respectively.

A wedge body 14 whose upper surface is an inclined surface 13 is placed on the lowermost support part 11.
The upper surface 12 of the support part 12 can be moved in the direction of inclination of the inclined surface 13 (here, in the left-right direction) by a hydraulic cylinder 15 fixed on the upper surface of the support part 12.

Above the wedge body 14, a pressure receiving member 25 is provided with an inclined surface 23 that engages with the inclined surface 13 and a supporting surface 24 that supports the workpiece (gear) 1.
1, the wedge body 14 is held so as to be movable in a direction perpendicular to the moving direction of the wedge body 14 (in the vertical direction here).

That is, the pressure receiving member 25 in this example includes a wedge body 26 whose lower surface is an inclined surface 23, a wedge body 26 connected to the wedge body 26 by a bolt 27, and a central support portion 21.
The pressure receiving block 29 is fitted into the through hole 28 of the pressure receiving block 29 and has its upper surface serving as the work supporting surface 24.

Further, a compression spring 30 is disposed between the wedge body 26 of the pressure receiving member 25 and the central support portion 21.

Further, a distortion correction tool (hereinafter simply referred to as a tool) 33 is held in the uppermost support portion 31 of the main body 10 .

The tool 33 consists of a chisel 35 having a retaining portion 34 of a predetermined shape, and a horizontal plate 37 connected to the chisel 35 by bolts 36.

Note that this example uses gear 1 shown in FIG. 1 as will be detailed later.
The engaging portion (head) 34 of the chisel 35 has a spline shaft shape whose diameter gradually decreases toward the tip.

Moreover, the diameter of the root side of the engaging portion 34 is larger than the diameter of the spline hole of the gear 1 in a state where no hardening distortion occurs.

Further, the body part 38 of the chisel 35 is fitted into the through hole 39 of the upper support part 310, and is movable in the same direction as the pressure receiving member 25, that is, in the vertical direction. The end surface 41 and the lower surface 42 of the horizontal plate 370 are the support portion 31
After being brought into contact with the lower surface 43 and upper surface 32 of , it is immovable.

In other words, the stroke of the tool 330 is limited to a certain range.

A press device (not shown) is installed above the horizontal plate 37 of the tool 33, and a ram 45 that can move up and down is pressed against the horizontal plate 3.
7 is pressurized.

Next, the operation of this embodiment will be described.

In this example, the quenching distortion that is expected to occur during carburizing of gear 1 shown in FIG. 1 is corrected in advance prior to carburizing.

The solid lines in FIG. 2 indicate the positions of each member before the hardening distortion of gear 1 is corrected.

As is clear from the figure, since the piston rod of the hydraulic cylinder 15 is retracted, the wedge body 14 is in a position to the right, while the pressure receiving member 25 has an inclined surface 23 that is relatively close to the inclined surface 13 of the wedge body 14. It is engaged with the left-side portion and is in the lowered position.

Further, as shown in FIGS. 2 and 3, the tool 33 is at its lowest position with the lower surface 42 of the horizontal plate abutting against the upper surface 32 of the upper support part due to its own weight.

At this time, the gear placed on the support surface 24 of the pressure receiving member 25
There is a certain distance between the upper end of the engagement part 1 and the lower end of the engagement part 34 of the tool 33.

From this state, when the piston rod of the hydraulic cylinder 15 shown in FIG. 2 is pushed out and the wedge body 14 is moved leftward, the pressure receiving member 25 is
is pushed upward.

When the pressure receiving member 25 is raised by the above distance, the A-th
As shown in the figure, the upper end of the gear 1 comes into contact with the engaging portion 34 of the tool 33 and supports it from below.

As the pressure receiving member 25 further rises, the tool 33 is pushed up until the upper end surface 41 of the engaging portion 34 comes into contact with the lower surface 43 of the horizontal plate, as shown in FIG.

That is, the tool 33 changes from the state shown in FIG. 3 to the state shown in FIG. It is lifted up.

In the state shown in FIG. 5, the gear 1 is rigidly supported from below.

Subsequently, the press device is operated, and the horizontal plate 37 of the tool 33 is pressurized by the descending ram 45.

At this time, a large downward force acts on the pressure receiving member 25, but
Since the angle of inclination of the inclined surfaces 13 and 23 is smaller than the friction angle between them, the wedge body 14 is in a self-locking state, and the wedge body 14 is not moved backward.

Therefore, the gear 1 remains rigidly supported from below and does not move at all, and as shown in FIG. I will do it.

The amount of descent of the tool 33 is regulated by the lower surface 42 of the horizontal plate coming into contact with the upper surface 32 of the support portion.

In other words, the engaging portion 34 of the tool 33 is connected to the pressure receiving member 25 and the gear from the state shown in FIG. 5 to the state shown in FIG.
The gear is supported by 1 and pushed up by the stroke.
The boss part 2 is fitted into the spline hole 3 of the boss part 2.
Expand the upper end by the planned amount.

Therefore, the magnitude of the pressing force applied by the ram 45 does not affect the amount of movement of the tool 33, and the press device equipped with the ram 45 can apply enough pressing force to expand the boss portion 2 of the gear 1. It is enough.

Once the end of the boss portion 2 of the gear 1 has been expanded, the piston rod of the hydraulic cylinder 15 is retracted, and the wedge body 14,
The gear 1 is taken out from the support surface 24 of the pressure receiving member 25 by moving the pressure receiving member 25 and the like in the opposite direction to that described above.

Next, when another gear is to be subjected to similar processing, there is no problem even if there are variations in dimensions, hardness, etc. between this gear and the gear 1.

The tool 33 remains constant from the state in which the upper end of the gear is in contact with the lower end of the engaging part 34 (see Fig. 4) until the upper end surface 41 of the retaining part is in contact with the lower surface of the horizontal plate 43 (see Fig. 5). This is because, after being raised by a distance, the horizontal plate lower surface 42 is pushed down by a stroke equal to the upward stroke until it comes into contact with the support part upper surface 32 (see FIG. 6).

Then, when the gear 1 taken out from the quenching distortion correction device 50 is carburized, the enlarged upper end of the boss portion 2 contracts, and the inner diameter of the spline hole 3 and the outer diameter of the boss portion 2 become equal in all parts. .

When hardening distortion occurs in a hole in which protrusions and grooves are formed alternately, such as a spline hole, it is extremely difficult to properly correct this distortion by cutting or grinding. This hardening distortion is successfully corrected.

In the above example, the quenching distortion that would occur during carburization of the workpiece was corrected in advance, but the heat treatment distortion correction method and device according to the present invention differs from the above example in that the heat treatment distortion such as carburizing and quenching It goes without saying that the present invention can be similarly applied to the case of correcting hardening distortion caused in a workpiece that has been subjected to the above process.

In this case, the procedure for correcting distortion is the same as in the previous example.

Further, since the gear 1, which is the workpiece in the above example, has an upper end portion of the boss portion 2 that contracts during heat treatment, the tool 33 is
Although the engaging portion 34 is shaped to expand this portion, the present invention can also be applied to the case where a specific portion of the workpiece is contracted.

That is, when a flange (workpiece) 52 equipped with a hexagonal cylindrical boss portion 51 as shown in FIGS. 7 and 8 is heat treated, if the diameter of the upper end of the boss portion 51 increases due to heat treatment distortion, then ( The amount and direction of heat treatment strain that occurs on the workpiece is actually determined for each workpiece), Tool 3 3
The engaging portion 34' may have a shape corresponding to this, that is, a shape whose diameter gradually increases toward the distal end.

It is extremely difficult to correct the heat treatment distortion caused in the rectangular tube-shaped boss portion 51 by grinding or the like as in this example, and the distortion correction method and device according to the present invention are well applied. .

In addition, as for the mechanism that supports the workpiece from below by raising and lowering the pressure receiving member, the one that utilizes the wedge action as in the example above is superior in that it can firmly support the workpiece with a simple structure. It can also be replaced with a jack device, etc.

In this case, the jack device is preferably a screw jack or the like that is self-locking when the pressure receiving member is pushed up.

In addition to this, the distortion correction method and device according to the present invention include:
It goes without saying that changes and improvements can be made as appropriate without departing from the spirit of the invention.

As described in detail above, according to the distortion correction method and device according to the present invention, there is no need to control the pressing force of the press device that applies pressure to the distortion correction tool, and the distortion correction tool does not need to control the movement start point and movement end point. Since the stroke is reliably regulated and always moved by a constant stroke, there is no need to provide a device to accurately regulate the stroke after the distortion correction tool contacts the workpiece, so the structure of the press device becomes simple. Even if the workpiece has a shape that cannot be corrected by machining, or even if there are variations in size and hardness among the workpieces, the heat treatment distortion can be well corrected, which is an excellent effect. be done.

[Brief explanation of drawings]

FIG. 1 is a front sectional view of a differential side gear as a workpiece to which the distortion correction method and device according to the present invention are effectively applied, and FIG. 2 is a front sectional view showing an embodiment of the distortion correction device according to the present invention. 3 to 6 are explanatory diagrams for explaining the operation of the embodiment shown in FIG. 2 (explanatory diagrams to help understand the distortion correction method according to the present invention), and FIGS. 7 and 8 are FIG. 7 is a plan view and a front sectional view showing another workpiece to which the distortion correction method and device according to the present invention are well applied. 1: Work (differential side gear), 2: Boss part, 3: Spline hole, 10: Device main body, 11, 21, 31: Support part, 13, 23: Inclined surface, 14: Wedge body, 24: Work support surface, 25 : Pressure receiving member, 33: Distortion correction tool, 34: Engagement part, 45: Ram, 50: Distortion correction device.

Claims (1)

[Claims] 1. A strain correction tool held movably in the axial direction within a limited range is moved to one end of the range by being pressed by the workpiece itself before or after heat treatment, and the workpiece is moved to one end of the range. The workpiece is characterized by applying pressure to the strain correction tool in a rigidly supported state to move the strain correction tool to the other end of the range, thereby plastically deforming the workpiece by an amount corresponding to the range. Heat treatment distortion correction method. 2. A device for correcting heat treatment distortion generated in a workpiece during heat treatment such as carburizing, quenching, etc., comprising: a device main body; a wedge body having an inclined surface and movable on the device main body in the direction of inclination of the inclined surface; a slope surface that engages with the slope surface of the wedge body; a support surface that supports the workpiece on the opposite side of the slope surface; a pressure receiving member held movably in a right angle direction; and an engaging portion having a shape corresponding to a shape of a portion of the workpiece whose heat treatment distortion is to be corrected on a side of the pressure receiving member opposite to the support surface. a distortion correction tool held in the apparatus main body so as to be movable by a certain stroke in the same direction as the moving direction of the pressure receiving member; and a distortion correction tool that is applied in a direction toward the support surface of the pressure receiving member. 1. A heat treatment distortion correction device comprising: a press device for compressing.