JP2002273543A - Parking gear having shaft, and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To integrally forge a parking gear with a shaft having the parking gear with a parking lock tooth formed on an outer circumferential surface on the outermost end part of a cylindrical shaft part side of a stepped shaft with spline on the inner and outer circumferential surfaces of the cylindrical shaft part and on the outer circumferential surface of a solid shaft part. SOLUTION: A primary formed stock W1 with a recess 18 formed in the center of one side of a parking gear part having a tooth profile on the outer circumferential surface and a shaft part 19 integrally protruded from the other side surface in a first forging step is restricted on its periphery in a second forging step, a tapered off punch 6 is inserted into the recess 18, and the shaft part is extruded forward to form a stepped shaft 19b with a large diameter cylindrical part and a small diameter solid part continued in two steps.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft-mounted parking gear used for an automatic transmission of an automobile and a method of manufacturing the shaft-mounted parking gear.

[0002]

2. Description of the Related Art A parking gear with a shaft is provided with at least one of a parking gear formed separately and at least one of inner and outer peripheral surfaces of a cylindrical shaft portion and an outer peripheral surface of a solid shaft portion continuous with the cylindrical shaft portion. In general, a stepped shaft having a spline is integrally formed using electron beam welding or the like.Then, to form the parking gear and the stepped shaft,
Forging means are exclusively used. As an example, after the parking gear is formed by forging and forging, the joints and the like are finished by cutting means, while the stepped shaft is formed by cutting a stepped round bar formed by forging, rolling, Holes and splines are formed on both inner and outer peripheral surfaces by using equipment such as broaching and machining.

[0003]

Since the two types of parts, the parking gear and the stepped shaft, are formed separately, the number of steps is naturally more than doubled, and the shaft is formed by rolling and broaching. Since it involves machining by machining and the like, enormous costs are required for its equipment and management. In addition, the stepped shaft must be subjected to two types of processing, such as cutting and boring, on a round bar formed by forging. To process a long round bar, a machine tool with a large distance between centers Is required. In addition, not only is it necessary to use appropriate equipment for joining by electron beam welding, but also the dimensional accuracy is not stable due to the effects of heat generated during welding, and there are also problems with the mutual positional relationship due to joining and the strength of the joining part. There is.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a parking gear having a shaft having a small number of steps, high accuracy and high reliability. The structure of the parking gear has parking lock teeth formed on the outer peripheral surface. A parking gear, and a stepped shaft having a spline on at least one of inner and outer peripheral surfaces of a cylindrical shaft portion and an outer peripheral surface of a solid shaft portion continuous with the cylindrical shaft portion, and the stepped shaft is formed by forging. A parking gear with a shaft formed integrally with a stepped shaft and a parking gear at the outermost end of the cylindrical shaft portion side, and a recess at the center of one side of a parking gear portion having a parking lock tooth formed on an outer peripheral surface thereof. A first forging step of molding a primary molded product that is recessed, and a solid shaft portion is integrally formed at the center of the other side, and a state in which the periphery of the primary molded product is constrained, and a taper tapered into the recess. Push punch with A second step of extruding the shaft portion forwardly into a stepped shaft in which a cylindrical large-diameter portion and a solid small-diameter portion are continuous in two stages, and a method of manufacturing a parking gear with a shaft, and an outer peripheral surface. A first forging step of molding a primary molded product in which a recess is formed in the center of one side of the parking gear portion where the parking lock teeth are roughly formed, and a solid shaft portion is integrally formed in the center of the other side. In a state where the periphery of the primary molded product is restrained, a tapered and tapered punch is pushed into the recess, and the shaft portion is moved forward to a stepped shaft in which a cylindrical large diameter portion and a solid small diameter portion are continuous in two stages. The second step of extrusion molding and the third step of pushing a straight punch into the cylindrical shaft portion and forming a spline on at least one of the inner and outer peripheral surfaces of the cylindrical shaft portion and the outer peripheral surface of the solid shaft portion And a method of manufacturing a parking gear with a shaft. And in the manufacturing method of the parking gear with a shaft, the second forging step is performed by extruding the shaft forward into a stepped shaft in which a cylindrical large diameter portion and a solid small diameter portion are continuous in two stages. In the step, the two-step continuous stepped shaft is divided into a post-stage in which a large-diameter cylindrical part, a middle-diameter cylindrical part and a small-diameter solid part are extruded into a three-step continuous shaft. Can be. In the present invention, a tapered punch is not only a shape gradually tapering from the base end to the tip end, but also a shape having a taper formed only at the tip end or a shape having the tip end rounded to a spherical surface. Including the punch.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a parking gear with a shaft and a method of manufacturing the parking gear with a shaft according to the present invention will be described with reference to the drawings. FIG. 1 shows a manufacturing apparatus used in the second forging step. In the present embodiment, the second forging step is constituted by two steps in which a post-step is added to a preceding step. First, the manufacturing apparatus (a) used in the previous stage will be described. 1 is a lower mold, 2 is an upper mold,
Is formed with a cavity 3 having a shape corresponding to the surface (the other end side) on the shaft-equipped side in the product shape of the shaft-equipped parking gear, and the lower portion of the cavity 3 corresponding to the three-stage stepped shaft is formed. It is opened, and the ejector 4 is incorporated in the opening. Also, in cavity 3,
A tooth profile 5 corresponding to the parking lock teeth is formed around a portion corresponding to the parking gear. Upper mold 2
Has a shape corresponding to the opposite surface (one end side) of the shaft-mounted parking gear in the product shape, and has a tapered punch 6 protruding at the center.

Next, the manufacturing apparatus (b) used at a later stage will be described. Reference numeral 7 denotes a lower die, 8 denotes an upper die,
Has a portion corresponding to a three-step stepped shaft,
At the center of the upper die 8, a punch having a two-stage structure in which a small-diameter punch 10 having a tapered taper is coaxially arranged at the tip of a straight punch 9 is protruded.

Next, the manufacturing apparatus (c) used in the third forging process will be described. In FIG.
Is an upper mold, and the lower mold 11 is provided with an outer spline molding tooth form 13 at a portion corresponding to a stepped shaft portion of a cavity in the lower mold 7 of the manufacturing apparatus used in the second step. , Around the part corresponding to the parking gear,
A parking lock tooth shaping tooth profile 14 is formed.
On the other hand, in the center of the upper die 12, a two-stage structure punch in which a straight punch 15 having a smaller diameter than the straight punch 9 'is coaxially arranged at the tip of the straight punch 9' is projected. Straight punch 9 '
An inner spline molding tooth profile 16 is provided on the outer periphery of the.

[0008] The second and third forging steps are performed by using the above-mentioned apparatus in order, and firstly, the procurement of a primary molded product is started. As shown in FIG. 3, the primary molded product W1 has a recess 18 in the center of one side of a parking gear portion having a tooth profile 17 formed on the outer peripheral surface, and a solid stepped shaft portion 19 on the other side. The primary molded product W1 is manufactured in a first forging step. Heat treatment, shot blasting, and lubrication are performed as necessary as an intermediate treatment.

In the stage before the second step, the primary molded product W
1 is set in the cavity 3 of the lower mold 1,
When the periphery is restrained and the tooth profile 17 is engaged with the tooth profile 5 and positioned, and the tapered punch 6 is pushed into the recess 18 by the lowering operation of the upper mold 2, the tapered punch 6 is pushed by the front extrusion. The formed portion is formed into a cylindrical large-diameter portion, and a small-diameter solid shaft portion is extruded at the tip to form a continuous shaft 19a that is continuous in two steps. Also, the work after molding can be taken out by raising the ejector 4 (FIG. 4).

In the subsequent stage of the second forging step, the upper large die 8 lowers the work set in the lower die 7 so that the cylindrical large diameter portion and the solid small diameter portion are continuous in two stages. By pressing the large and small two-stage straight punch 9 and the tapered small-diameter punch 10 into the cylindrical large-diameter portion of the stepped shaft 19a, the two-stage continuous stepped shaft 19a is formed into a cylindrical large-diameter portion and a cylindrical medium-diameter. The part and the solid small-diameter part are extruded and formed on a stepped shaft 19b which is continuous in three steps (FIG. 5). In the second forging step, since the punches are all tapered, the meat of the work flows smoothly in the punching direction, and efficient extrusion is realized. In addition, the formation of the hole and the extrusion are performed simultaneously by pushing the punch, which is extremely rational.The long stepped shaft is formed while gradually extending from the starting material with a short shaft, so it depends on the length of the shaft. It can be said that it is economical to use devices with different strokes.

In the final third forging step, the cavity 3
The outer spline molding tooth profile 13 provided at a portion corresponding to the stepped shaft portion and the inner spline molding tooth profile 16 formed on the straight punch 9 ′ form the outer peripheral surface of the cylindrical medium diameter portion and the cylindrical large diameter. The outer spline 20 and the inner spline 21 are formed on the inner peripheral surface of the radial portion, respectively, and the parking tooth profile 17 which has been roughened is coined by the parking tooth shaping tooth profile 14 (FIG. 6). Thus, as shown in FIG. 7, the outer spline 20 and the inner sprocket 20 are respectively formed on the outer peripheral surface of the shaft portion and the inner peripheral surface of the cylindrical large-diameter portion. Three-step continuous shaft 19c having a spline 21
A parking gear with a shaft coupled with is integrally formed by forging.

In the above embodiment, a solid shaft portion of a primary molded product,
Both the inner and outer peripheral surfaces of the molded product are stepped, but the stepless shape, that is, the cylindrical shaft portion and the solid shaft portion are each straight without step, or conversely, there may be three or more steps, The spline is applied to at least one of the inner and outer peripheral surfaces of the cylindrical shaft portion and the outer peripheral surface of the solid shaft portion. In addition, the second forging process is advantageous in that a long shaft portion is extruded forward if a later stage is added, but it can be performed not only in two stages but also in one stage, and conversely, in two or more stages. May be performed in a plurality of stages. Further, in the present invention, not only the parking lock teeth, but also the type of gear such as a spur gear or a helical gear does not matter, and the spline may have a keyway shape, for example. The shaping of the teeth and the formation of the splines may be performed by machining.

[0013]

According to the present invention, by being integrally formed by forging, the manufacturing process is simplified, and there is no need for a joining process such as electron beam welding. We can provide products with rich sex. Further, the use of a tapered punch with a tapered shape improves the front extrusion efficiency, and allows the solid shaft to be smoothly and smoothly extruded. Furthermore, it is rationalized by simultaneously forming and extruding holes by pushing a punch, and when the second forging process is divided into a pre-stage and a post-stage, in the pre-stage, the stroke of the molded product is shorter due to a shorter shaft portion. Short devices are available.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an apparatus used in a second forging step in the method of the present invention.

FIG. 2 is an explanatory view of an apparatus used in a third forging step in the method of the present invention.

FIG. 3 is an explanatory diagram of a primary molded product.

FIG. 4 is an explanatory diagram of a previous stage in a second forging process.

FIG. 5 is an explanatory diagram of a later stage in a second forging process.

FIG. 6 is an explanatory view and a completed view of a third forging step.

FIG. 7 is an explanatory view of a parking gear with a shaft.

[Explanation of symbols]

1. Lower die, 2. Upper die, 3. Cavity, 4. Ejector, 5. Teeth shape (corresponding to parking lock teeth), 6. Tapered punch, 7. Lower die, 8. · Upper die, 9, 9 '· · · Straight punch, 10 · · · Small diameter punch with taper, 11 · · · Lower die, 12 · · · Upper die, 13 · · ·
Tooth profile for outer spline molding, 14 ・ ・ Tooth profile for parking lock tooth shaping, 15 ・ ・ Small diameter straight punch, 16 ・
・ Inner spline molding tooth mold, 17 ・ ・ Tooth profile, 18 ・ ・ Recess, 19 ・ ・ Stepped shaft part, 19a ・ ・ Stepped shaft continuous in two steps, 19b ・ ・ Stepped shaft continuous in three steps, 19c
・ Three steps of stepped shaft (with spline), 20 ・
・ Outer spline, 21 ・ ・ Inner spline, W1 ・ ・ Primary molded product.

Claims (4)

[Claims] 1. A spline is provided on at least one of a parking gear having parking lock teeth formed on an outer peripheral surface thereof and at least one of an inner and outer peripheral surfaces of a cylindrical shaft portion and an outer peripheral surface of a solid shaft portion continuous with the cylindrical shaft portion. And a stepped shaft having a stepped shaft and a parking gear formed coaxially and integrally with the stepped shaft at an end of the stepped shaft on the cylindrical shaft portion side. 2. A recess is formed in the center of one side of a parking gear portion having parking lock teeth formed on an outer peripheral surface thereof,
A first forging step of molding a primary molded product in which a solid shaft portion is integrally formed at the center of the other side surface, and a punch having a tapered taper in a recess while the periphery of the primary molded product is restrained. A second step of pushing the shaft portion forward and extruding the shaft portion into a stepped shaft in which a cylindrical large diameter portion and a solid small diameter portion are continuous in two stages. 3. A recess is formed in the center of one side surface of a parking gear portion having parking lock teeth formed on an outer peripheral surface thereof,
A first forging step of molding a primary molded product in which a solid shaft portion is integrally formed at the center of the other side surface, and a punch having a tapered taper in a recess while the periphery of the primary molded product is restrained. A second step of extruding the shaft portion forward and extruding the shaft portion into a stepped shaft in which a cylindrical large diameter portion and a solid small diameter portion are continuous in two stages, and pushing a straight punch into the cylindrical shaft portion, at least the cylindrical shaft portion. A step of forming a spline on one of the inner and outer peripheral surfaces and the outer peripheral surface of the solid shaft portion. 4. A second forging step, wherein the shaft portion is continuous with the two stages before the front extrusion molding of the shaft portion into a stepped shaft in which a cylindrical large diameter portion and a solid small diameter portion are continuous in two stages. Stepped shaft,
4. A parking gear with a shaft according to claim 2, wherein a post-stage in which the cylindrical large-diameter portion, the cylindrical medium-diameter portion and the solid small-diameter portion are extruded into a stepped shaft continuous in three stages is added. Manufacturing method.