JP2009190052A - Cold forging method - Google Patents

Abstract

A lubricant applied to a workpiece is dried to form a lubricant film, and then, when this workpiece is subjected to cold forging, seizure and lack of thickness are avoided.
A third preform 28 (work) serving as an outer member 12 of a constant velocity joint is heated in advance, and then an aqueous lubricant is sprayed while the third preform 28 is rotated. The aqueous lubricant is applied substantially uniformly over the entire inner wall and outer wall of the cup portion 22 of the third preform 28. Immediately after the application is completed, hot air is supplied from the hot air supply devices 44 and 46 and dried before the aqueous lubricant flows to form a lubricating film.
[Selection] Figure 4

Description

  The present invention relates to a cold forging method in which cold forging is performed after applying a water-based lubricant to a workpiece.

  An outer ring member of a constant velocity joint constituting an automobile traveling engine is generally subjected to forward extrusion molding, upsetting molding, backward extrusion molding and ironing molding in order for a cylindrical workpiece made of carbon steel. It is manufactured by plastically deforming a carbon steel workpiece into the shape of an outer ring member. Among these, the ironing is usually performed by cold forging.

  Here, when carrying out the cold forging process, in order to avoid causing seizure, rough skin, etc., for example, lubrication comprising a phosphate such as zinc phosphate, iron phosphate, manganese phosphate, calcium phosphate, etc. Forming a film on the surface of a workpiece and applying a lubricant such as metal soap to the surface are widely practiced. However, in this case, pretreatment such as degreasing is also required before forming the lubricating film. Therefore, Patent Document 1 proposes to apply a lubricating oil (oil-based lubricant) containing an organophosphorus compound instead of this type of lubricating film formation and lubricant application.

  In any conventional technique, the cold forging process on the workpiece is performed by a publicly known method such as brush coating, spraying method, dipping method, fluidized dipping method (see Patent Document 1, column 6, lines 31 to 34). The applied lubricant is not dried, in other words, the wet lubricant is left wet.

Japanese Patent Publication No. 2-18720

  In contrast to the prior art as described above, the present applicant has attempted to dry the lubricant to form a lubricating film. This is because the working environment is prevented from being contaminated by dripping the lubricant from the workpiece.

  However, in this case, there is a problem that seizures and undercutting occur relatively frequently.

  The present invention has been made to solve the above-described problems, and provides a cold forging method that can avoid contamination of the work environment and can significantly reduce the occurrence frequency of seizure and undercutting. The purpose is to do.

  While examining the reason why seizure and undercutting occur relatively frequently when the lubricant is dried, the inventor has increased the frequency of seizure and undercutting as the variation in the thickness of the lubricant film increases. The knowledge that becomes higher. In particular, when the workpiece was immersed in the lubricant, a tendency was found that the variation in the thickness of the lubricant film increased.

  Based on the above knowledge, the present inventor has conducted extensive studies on a technique for reducing the variation in the thickness of the lubricating film as much as possible, and has come to the present invention.

That is, the present invention is a cold forging method in which a cold forging process is performed on the workpiece after applying a water-based lubricant to the workpiece.
Applying the aqueous lubricant to the workpiece by spraying the aqueous lubricant toward the workpiece;
Drying the aqueous lubricant before the aqueous lubricant applied to the workpiece flows to form a lubricating film;
Applying cold forging to the workpiece on which the lubricating film is formed;
It is characterized by having.

  In other words, in the present invention, the aqueous lubricant is sprayed on the workpiece to apply the aqueous lubricant substantially evenly, and then dried before the aqueous lubricant flows. In other words, in the present invention, the aqueous lubricant does not flow and aggregate, and no droplets of the aqueous lubricant are formed. For this reason, a lubricating film having a substantially uniform thickness is formed.

  When a cold forging process is performed on a workpiece having such a lubricating film formed on its surface, the frequency of occurrence of seizure, undercutting, etc. is significantly reduced. That is, a product without forging defects can be manufactured with a high yield.

  Of course, since the water-based lubricant is quickly dried to form a lubricating film, for example, the water-based lubricant is not dripped when the workpiece is transported to the forging station. Naturally, the working environment is not contaminated.

  In addition, it is preferable to preheat the work before applying the aqueous lubricant to the work. The aqueous lubricant that has contacted the heated workpiece dries more rapidly. For this reason, it becomes easier to prevent the aqueous lubricant from flowing, and eventually it becomes easy to form a lubricating film having a substantially uniform thickness. As a result, it is possible to further reduce the occurrence frequency of seizures, undercuts and the like.

  In any case, it is preferable to apply the aqueous lubricant while rotating the workpiece. In this case, since the amount of the aqueous lubricant applied to each part of the workpiece is substantially equal to each other, it is remarkably easy to make the thickness of the lubricant film formed on each part of the workpiece substantially equal to each other. is there.

  Here, as a preferable example of the work, a preformed outer member constituting the constant velocity joint can be cited.

  According to the present invention, a water-based lubricant is sprayed on a work piece approximately uniformly to apply a water-based lubricant, and then dried before the water-based lubricant flows to form a lubricant film having a substantially uniform thickness. Like to do. In a workpiece having such a lubricating film formed on the surface, when cold forging is performed, the frequency of occurrence of seizure, undercutting, etc. is significantly reduced. For this reason, a product without forging defects can be manufactured with a high yield.

  In addition, since the aqueous lubricant applied to the workpiece does not drip from the workpiece, it is possible to avoid contamination of the work environment.

  Hereinafter, the cold forging method according to the present invention will be described in detail with reference to the accompanying drawings by giving a preferred embodiment by exemplifying the case of producing an outer member of a constant velocity joint.

  FIG. 1 is a flowchart schematically showing the process from the cylindrical billet 10 as a starting material to the outer member 12 being obtained. As shown in FIG. 1, before the outer member 12 is manufactured, the billet 10 is subjected to forward extrusion molding, upsetting molding, backward extrusion molding, and ironing molding.

  That is, first, a forward extrusion molding is performed on the billet 10. Specifically, the billet 10 is pressed from the other end surface side while the one end surface of the billet 10 is supported. Along with this, the other end surface is crushed, and as a result, a primary preform 20 is obtained in which the large-diameter portion 14, the reduced-diameter portion 16 reduced in a taper shape, and the shaft portion 18 are formed.

  Next, upsetting is performed on the primary preform 20 transferred to the upsetting apparatus. That is, only the large-diameter portion 14 of the primary preform 20 is crushed so that the large-diameter portion 14 is expanded to obtain the secondary preform 24 having the cup portion 22.

  Next, the second preformed body 24 transferred to the rear extrusion molding device is subjected to rearward extrusion molding to extend the cup portion 22 and to form three guide grooves 26 a to 26 c in the cup portion 22. . That is, a punch having a projecting portion for forming the guide grooves 26a to 26c is brought into contact with the central portion of one end face of the cup portion 22, and then the tip portion of the shaft portion 18 is pressed to perform the second preliminary molding. The body 24 is displaced toward the punch. As a result, the third preform 28 is obtained.

  The third preform 28 is transferred to the ironing device via a transfer device such as a transfer in a state where the cup portion 22 is directed vertically downward. In the present embodiment, during this transfer, normal temperature air or hot air is supplied to the third preform 28 by a wind supply mechanism such as a blower or a hot air supply device installed in the vicinity of the transfer device. Then, a lubricating film is formed as described later.

  The heating is preferably performed so that the third preform 28 has a temperature at which an aqueous lubricant described later can be quickly dried. This temperature may be set according to the type of water-based lubricant. For example, if the temperature of the third preform 28 is 75 ° C. or higher, preferably 80 to 85 ° C. Good.

  As shown in FIGS. 2 to 5, the temperature of the third preform 28 is increased. The shaft portion 18 is provided at the tip of an arm portion 30 of a robot (not shown) via a rotating shaft 32. It is gripped by the chuck 34 and transferred to the middle of the booth 36 in this state. During this transfer, a lubricating film is formed on the third preform 28.

  The booth 36 is provided with a long housing 38. As can be understood from FIGS. 2 to 6, the housing 38 has a first spray nozzle 40 (see FIG. 2), a second spray nozzle 42 (see FIG. 3), and hot air supply devices 44 and 46 (see FIG. 2). 4), a displaceable rotary table 48 (see FIG. 5), and a third spray nozzle 50 (see FIG. 6) are arranged in this order from the upstream side. Further, in the vicinity of the first spray nozzle 40, the second spray nozzle 42, and the third spray nozzle 50, a first suction duct 52, a second suction duct 54, and a third suction duct 56 are connected, respectively.

  A long insertion port 58 is formed in the ceiling portion of the housing 38, and the arm portion 30 is passed through the insertion port 58. The chuck 34 can be rotated under the action of the rotating shaft 32.

  The first spray nozzle 40, the second spray nozzle 42, and the third spray nozzle 50 may have the same shape. As these 1st spray nozzle 40, 2nd spray nozzle 42, and 3rd spray nozzle 50, the comparatively wide angle spray type whose spray range angle is 50 degrees-55 degrees is employable, for example.

  When the arm portion 30 moves and the rotating shaft 32 is inserted into the housing 38, the rotating shaft 32 starts rotating. Of course, the third preform 28 also rotates with this. In this state, as shown in FIG. 2, the aqueous lubricant LB is sprayed from the first spray nozzle 40 toward the third preform 28. In addition, what is necessary is just to set the rotation speed of the 3rd preform 28, and application | coating (spraying) time of water-based lubricant LB to about 60 rpm and about 1 second, for example.

  In this case, the frame 60 that supports the first spray nozzle 40 is installed below the housing 38, and the first spray nozzle 40 faces upward. For this reason, the aqueous lubricant LB sprayed from the first spray nozzle 40 can be easily applied to the inner wall of the cup portion 22 of the third preform 28.

  In this application, since the third preform 28 is rotating as described above, the aqueous lubricant LB adheres substantially uniformly over the entire inner wall of the third preform 28.

  It should be noted that an angle θ1 formed by an extension shaft from the center of the first spray nozzle 40 and a center axis of the chuck 34 (third preform 28) is within a range of 25 ° to 45 °, and the first spray nozzle 40 and the first spray nozzle 40 If the lateral separation distance L1 with the tertiary preform 28 is appropriately adjusted within the range of 45 to 105 mm, and the longitudinal separation distance H1 between the first spray nozzle 40 and the chuck 34 is appropriately adjusted within the range of 180 to 280 mm, the aqueous The lubricant LB can be reliably applied to the entire inner wall of the cup portion 22.

  The aqueous lubricant LB applied to the inner wall of the cup portion 22 is quickly preliminarily dried because the third preform 28 is preheated as described above. That is, the liquid component evaporates and only the solid lubricating component remains.

  Immediately after the aqueous lubricant LB is applied to the inner wall of the cup portion 22, the arm portion 30 is quickly displaced. As a result, as shown in FIG. 3, the third preform 28 is recently placed in the second spray nozzle 42. Touch. In this case, the frame 62 that supports the second spray nozzle 42 is installed above the housing 38, and the third preform 28 is positioned below the second spray nozzle 42. For this reason, the aqueous lubricant LB sprayed from the second spray nozzle 42 facing downward is applied to the outer wall of the cup portion 22 of the third preform 28.

  At this time as well, the rotating shaft 32 and thus the third preform 28 are rotated. For this reason, the sprayed water-based lubricant LB adheres substantially uniformly over the entire outer wall of the cup portion 22 of the third preform 28. The number of rotations of the third preform 28 and the application (spraying) time of the aqueous lubricant LB can be set to about 60 rpm and about 1 second, for example, as described above.

  In order to reliably apply the aqueous lubricant LB over the entire outer wall of the cup portion 22, an extension shaft from the center of the second spray nozzle 42 and a central shaft of the chuck 34 (third pre-formed body 28) are provided. Is within the range of 25 ° to 45 °, the lateral separation distance L2 between the second spray nozzle 42 and the third preform 28 is within the range of 90 to 150 mm, the second spray nozzle 42 and the chuck 34. The vertical separation distance H2 may be adjusted as appropriate within a range of 0 to 100 mm.

  The aqueous lubricant LB applied to the outer wall of the cup portion 22 is also quickly preliminarily dried. This is because the third preform 28 is preheated as described above.

  Immediately after the aqueous lubricant LB is applied to the outer wall of the cup portion 22 in this way, the arm portion 30 is quickly displaced, and as a result, the third preform 28 is heated as shown in FIG. Closest to wind supply 44,46. The hot air supplied from the lower hot air supply device 44 comes into contact with the inner wall of the cup portion 22, and the hot air supplied from the hot air supply device 46 in the middle of the longitudinal direction of the housing 38 is applied to the outer wall of the cup portion 22. Contact. Of course, the third preform 28 is also rotated at this time. Accordingly, warm air contacts the entire outer wall of the cup portion 22. The warm air may be about 80 ° C.

  By contacting the hot air in this manner, the aqueous lubricant LB applied to the inner wall and the outer wall of the cup portion 22 is dried without flowing. Thereby, a lubricating film is formed.

  Moreover, in the present embodiment, as described above, the aqueous lubricant LB is preliminarily dried. Accordingly, the aqueous lubricant LB is further suppressed from flowing.

  As described above, in the present embodiment, the water-based lubricant LB is applied to the inner wall and the outer wall of the third preform 28 substantially uniformly and then dried before the water-based lubricant LB flows to form a lubricating film. To form. For this reason, it is possible to avoid the water-based lubricant LB from agglomerating or forming droplets, and as a result, a lubricating film having a substantially uniform thickness can be obtained.

  The third preform 28 with the lubricating film having a substantially uniform thickness formed on the inner wall and the outer wall of the cup portion 22 is then transferred to the rotary table 48 shown in FIG. 5 when the arm portion 30 is displaced. The On the rotary table 48, the third preform 28 is released as the chuck 34 opens. That is, the third preform 28 is placed on the rotary table 48 with the cup portion 22 facing the rotary table 48.

  A plurality of the rotary tables 48 are provided on a conveyor (not shown) so that each of them can be rotated under the action of a rotating mechanism (not shown). The conveyor is operated such that its belt (not shown) is directed from the upstream side to the downstream side of the housing 38, and therefore the third preform 28 is transferred to the third spray nozzle 50 shown in FIG. It is transferred to.

  The frame 64 that supports the third spray nozzle 50 is installed above the housing 38. On the other hand, the third preform 28 placed on the rotary table 48 is positioned below the third spray nozzle 50. In this state, the rotary table 48 is urged to rotate under the action of the rotating mechanism, and the third preform 28 is rotated accordingly.

  Then, the aqueous lubricant LB is sprayed from the third spray nozzle 50 onto the rotating third preform 28. The third spray nozzle 50 faces the reduced diameter portion 16 and the shaft portion 18, and accordingly, the aqueous lubricant LB sprayed from the third spray nozzle 50 is reduced in the reduced diameter portion 16 and the third preform 28. It is applied to the shaft portion 18. Since the third preform 28 is rotating as described above, the water-based lubricant LB is applied substantially uniformly over the entire side peripheral walls of the reduced diameter portion 16 and the shaft portion 18. At this time, the rotational speed of the third preform 28 and the application (spraying) time of the aqueous lubricant LB may be set to, for example, about 60 rpm and about 1 second.

  In order to reliably apply the water-based lubricant LB over the entire side peripheral wall of the reduced diameter portion 16 and the shaft portion 18, the extension shaft from the center of the third spray nozzle 50 and the center of the third preformed body 28. The angle θ3 formed by the shaft is in the range of 60 ° to 80 °, the lateral separation distance L3 between the third spray nozzle 50 and the third preform 28 is in the range of 140 to 200 mm, and the third spray nozzle 50 What is necessary is just to adjust suitably the vertical direction separation distance H3 with the turntable 48 within the range of 100-200 mm.

  Since the third preform 28 is heated in advance as described above and further exposed to hot air when the aqueous lubricant LB applied to the inner wall and outer wall of the cup portion 22 is dried, the third preform 28 is exposed to the third preform 28. The preform 28 is still in a state where the temperature has increased. Therefore, the aqueous lubricant LB applied to the side peripheral walls of the reduced diameter portion 16 and the shaft portion 18 is also quickly dried to form a lubricating film.

  While the water-based lubricant LB is applied to the third preform 28 as described above, a mist-like water-based lubrication is performed via the first suction duct 52, the second suction duct 54, and the third suction duct 56. Agent LB is captured.

  The third preform 28 having the lubricating film formed thereon is led out from the booth 36 as the conveyor belt is exposed from the housing 38 and further dried, and then transferred to the ironing apparatus. The Since the aqueous lubricant LB has already been dried, the aqueous lubricant LB does not drop from the third preform 28 during this transfer. Of course, the working environment is not contaminated by the dropped aqueous lubricant LB.

  The third preform 28 is set in a mold constituting the ironing apparatus. Thereafter, ironing (cold forging) is performed on the third preform 28 under the action of the ironing device, and as a result, the outer member 12 shown in FIG. 1 is formed.

  As described above, the third preform 28 is formed with a lubricating film having a substantially uniform thickness over the shaft portion 18, the reduced diameter portion 16, and the inner and outer walls of the cup portion 22. When the cold forging process is performed on the third preform 28 having such a lubricating film formed, the frequency of occurrence of forging defects such as seizure and chipping is significantly reduced.

  That is, according to the present embodiment, there is an advantage that the outer member 12 having a predetermined shape can be manufactured with a high yield.

  In the above-described embodiment, the third preform 28 that is the outer member 12 constituting the constant velocity joint has been exemplified and described as a workpiece. However, the workpiece is not particularly limited to this, Any material can be used as long as it is subjected to cold forging.

  In addition, for example, if the workpiece is relatively small and, for this reason, it is possible to apply the aqueous lubricant to all parts by one spray, it is not particularly necessary to apply the aqueous lubricant LB while rotating the workpiece. .

  Furthermore, the spray nozzle may be selected with a spray range angle corresponding to the shape and size of the workpiece, and the installation position of the spray nozzle, the application conditions of the aqueous lubricant, etc., also depend on the shape and size of the workpiece. What is necessary is just to set suitably.

  Further, a blower that supplies normal temperature air may be employed instead of the hot air supply devices 44 and 46. That is, it is not particularly necessary to supply hot air to dry the aqueous lubricant LB, and normal temperature air may be used.

It is the flow which showed roughly the process until the outer member of a constant velocity joint is obtained from a billet. It is a schematic longitudinal cross-section block diagram which shows the state which has apply | coated the aqueous | water-based lubricant to the inner wall of the cup part of the tertiary preforming body used as the said outer member. It is a schematic longitudinal cross-section block diagram which shows the state which has apply | coated the aqueous lubricant to the outer wall of the cup part of the said 3rd preform. It is a schematic longitudinal cross-section block diagram which shows the state which has dried the aqueous | water-based lubricant apply | coated to the inner wall and outer wall of the cup part of the said 3rd preform. It is a schematic longitudinal cross-sectional block diagram which shows the state which released the said 3rd preform from the chuck | zipper and mounted in the rotary table. It is a schematic longitudinal cross-section block diagram which shows the state which has apply | coated the aqueous lubricant to the side peripheral wall of the axial part of the said 3rd preform.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Billet 12 ... Outer member 18 ... Shaft part 20, 24, 28 ... Pre-formed body 22 ... Cup part 32 ... Rotating shaft 34 ... Chuck 36 ... Booth 38 ... Housing 40, 42, 50 ... Spray nozzle LB ... Aqueous lubricant

Claims (4)

In the cold forging method in which a cold forging process is performed on the workpiece after applying the aqueous lubricant to the workpiece,
Applying the aqueous lubricant to the workpiece by spraying the aqueous lubricant toward the workpiece;
Drying the aqueous lubricant before the aqueous lubricant applied to the workpiece flows to form a lubricating film;
Applying cold forging to the workpiece on which the lubricating film is formed;
A cold forging method characterized by comprising:   The cold forging method according to claim 1, wherein the work is heated before the aqueous lubricant is applied to the work.   The cold forging method according to claim 1 or 2, wherein the aqueous lubricant is applied while rotating the workpiece.   The cold forging method according to any one of claims 1 to 3, wherein the workpiece is a preform of an outer member constituting a constant velocity joint.

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