JP2003326330A - Spacer for drive pinion and production method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide spacers for drive pinions by hydroforming, and to provide a production method therefor. <P>SOLUTION: A material pipe 1 is subjected to hydroforming to produce spacers 10 for drive pinions used for the differentials of a vehicle. The material pipe 1 having a hardness Hv of 100 to 125 is subjected to hydroforming under the forming pressure of 70 to 130 MPa to form the material pipe 1 so that the central part is made into a large-diameter part 13, an both edge parts are made into small-diameter parts 11. Thereafter, the large-diameter part 13 in the material pipe 1 is separated to produce two spacers 10 having almost the same shape. In this case, sufficient hardness is secured in both edge parts of the spacers 10, and wear and failures accompanying the wear are made less liable to be caused, and also, the occurrence of deformation on the insides of the spacers 10 is more securely prevented. Further, the spacers 10 provided with different load properties are formed from the same die. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive pinion spacer used for a vehicle differential and a manufacturing method thereof.

[0002]

2. Description of the Related Art FIGS. 13A and 13B are a plan sectional view and a side sectional view, respectively, of a vehicle differential 100. The illustrated vehicle differential 100 includes a reduction pinion (drive pinion) 41,
It has a large reduction gear (drive bevel gear) 42, a differential case 43, a small differential gear (differential pinion) 44, and large left and right differential gears (differential side gears) 45, and converts the rotation speed and torque of the transmission, Power is transmitted to driving wheels (not shown). As shown in the figure, since the differential 100 changes the power transmission direction to a right angle and transmits the power to the drive wheels, a load is applied to both the radial and thrust of the shaft portion 40 of the reduction gear 41. For this reason, a pair of taper bearings 50a and 50b are used as bearings for the shaft portion 40 of the reduction gear 41.

In the differential 100 shown in FIG. 13, when the displacement between the gears is large, an impact is generated when the teeth of the gears are meshed with each other, and differential gear noise is generated. Therefore, it is necessary to secure sufficient supporting rigidity and normal tooth contact in the gear system of the differential 100. Conventionally, in order to keep the displacement between the gears of the differential 100 small, the large gear 42 supports the small gear 41 on both sides, and a thrust bolt 47 is provided on the rear surface of the large gear to strengthen the rigidity. Further, the bearing rigidity is increased by applying a pressure to the bearings 50a and 50b supporting small gears, and the relative displacement between the gears of the differential 100 is kept small.

Conventionally, in order to apply a pressure to the bearings 50a, 50b supporting small gears, the spacer 10 is inserted between the inner rings of the bearings 50a, 50b, and the nut 51 holding the flange 52 is tightened. The proper tightening torque is applied to. When the non-adjustable spacer 10 is used, the nut 51 is tightened to deform the spacer 10 in the axial direction, and pressurization is set for each of the tapered bearings 50a and 50b on both sides of the spacer 10. There is. At this time, if excessive pressurization is applied, the differential 100 will have a temperature rise, an increase in wear torque, a decrease in life, and an increase in gear noise.
Furthermore, if looseness occurs due to wear or the like, the spacer 1
The tightening load of 0 is reduced, and the bearings 50a and 50b are loosened. Therefore, the spacer 10 is tightened with an appropriate load for each vehicle type when assembled,
It is set so as not to cause sliding between the bearings 50a and 50b abutted on both ends. However, it is difficult to maintain the properly set pressurization of the bearings 50a and 50b, and when the spacer 10 slightly slides due to vibration during operation, as a result, wear occurs at the end surface of the spacer 10. In some cases, problems such as oil (lubricating oil) leakage occurred. Therefore, it is necessary to prevent wear of the end surface of the spacer 10 as much as possible. As a countermeasure against this, conventionally
The hardness of the end face is finished by heat treatment, but this is a process different from the process of processing the spacer 10, which causes a rise in manufacturing time and cost.

Further, the drive pinion spacer 10 has the property that once it is used and compressed, it cannot be reused because the amount of plastic deformation does not return. Therefore, the spacer 10 that cannot be tightened with an appropriate load
Need to be replaced promptly. However, conventionally, the spacer 10 may be deformed inward, which may hinder the work of quickly removing the spacer 10 from the shaft portion 40 of the reduction gear 41 during maintenance.
FIG. 14A is a diagram showing the spacer 10 in which the deformation (protrusion) 2 is generated inside. When a slight overhang 2 is generated inside the spacer 10, it is difficult to visually confirm the overhang 2, and therefore, in the past, the overhang 2 may be assembled in the differential 100 in this shape. This overhang 2 itself does not impair the original purpose of the spacer 10 that applies pressure to the bearing 50 (see FIG. 13), however, the spacer 10 is not removed when the overhang 2 is formed on the spacer 10. When compressed under pressure, Fig. 1
As shown in FIG. 4B, the inward deformation 3 was continuously generated in the spacer 10. This is because when the spacer 10 is compressed, the bulging portion is compressed as indicated by reference numeral 12 ′, so that a force to be pushed inward is exerted on the extra thickness 2 in the vicinity. In this case, the amount of deformation 3 causes the spacer 10 to be tightly coupled to the shaft portion 40 (see the dotted line s-s) of the reduction gear 41 shown in FIG. In such a state, when the spacer 10 is replaced during maintenance (the spacer 10 may be removed even when the parts other than the spacer 10 are replaced), it is necessary to replace the reduction gear 41 itself. However, since the differential 100 in recent years is required to be even quieter, the differential gear increases the number of teeth to increase the meshing ratio, improves accuracy, and makes noise performance advantageous, and the gear is expensive. It has become a thing. Further, the shaft portion 40 to which the spacer 10 is attached is usually integrally formed with the pinion gear 41 in order to enhance strength and facilitate processing. Therefore, replacement of the reduction pinion 41 integrated with the spacer 10 for replacement of the spacer 10 is an uneconomical choice for the user and is not preferable.

Further, since the spacer 10 needs to be tightened with an appropriate load for each vehicle type, the spacer 10 is usually manufactured to have different load characteristics for each vehicle type. This is because the load applied to the differential changes as the vehicle type changes, so the bearing 5 supporting the small gear
This is because the magnitude of the pressure applied to 0a and 50b also changes. However, the load characteristic refers to the relationship between the compressive load applied to the spacer 10 and the displacement of the spacer 10. Conventionally, the shape of the spacer 10 has generally been changed in order to change the load characteristics of the spacer 10 for each vehicle type. However, in this case, it is necessary to prepare different molds for the spacer for each vehicle type. In addition, a dedicated die and a jig for guiding and controlling the cutting tool are also required in post-processing such as cutting and end face processing. Further, when the molds are changed for each vehicle type, the number of molds required is large, so that a work time for replacing the molds is required, and thus the work process is likely to be wasteful.

Therefore, conventionally, a sufficient hardness is secured on both end surfaces of the spacer so that the end surfaces are less likely to be worn and the defects associated therewith, and the inner deformation of the spacer is more reliably prevented. Further, there is a demand for a drive pinion spacer that can be molded from the same mold so as to have different load characteristics, and a manufacturing method thereof.

Conventionally, as a method of manufacturing a drive pinion spacer, machining by a mechanical press and hydroforming by a hydraulic press have been mainly used.

For example, as a prior art relating to a method for manufacturing a drive pinion spacer by mechanical pressing, there is a method for manufacturing a drive pinion spacer disclosed in Japanese Patent No. 2895748. Further, as a prior art relating to a method of manufacturing a mechanical part by a hydraulic press, Japanese Patent Publication No.
The bulge forming apparatus disclosed in Japanese Patent Publication No. 6-4332 and the manufacturing apparatus and method for a turnbuckle disclosed in Japanese Utility Model Publication No. 3-41860 and Japanese Patent Publication No. 5-42564 can be cited.

In the method for manufacturing a drive pinion spacer disclosed in Japanese Patent No. 2895748, the maximum load reaches a predetermined range in the process of axially pushing the spacer provided on the outer periphery of the drive pinion through the bearing. It is an object of the present invention to provide a method of manufacturing a spacer, which has a gentle drop in load after being subjected to the above-mentioned process and whose load is maintained within a predetermined range for a long time, by a mechanical press without variations in products. In particular,
A drive pinion spacer that is mounted on the outer periphery of the drive pinion of a vehicle to position the front and rear bearings, and has a chevron-shaped bulging portion that acts as a springback on a steel pipe. In a method of manufacturing by a mechanical press, a first bulge step of pre-processing one inclined portion of the bulging portion in a steel pipe and a step of pre-processing the inclined portion at a predetermined inclination angle A second bulge process for working the plate thickness thinner than other parts, a necking process for working the other inclined part of the bulging part and the subsequent tubular part, and a rest-like process for finishing the tubular part. The present invention provides a method for manufacturing a drive pinion spacer comprising

The bulge molding apparatus disclosed in Japanese Patent Publication No. 56-4332 generally compresses a molding medium such as liquid or molding rubber with a pressure mold, and a molding target is interposed between the molding medium and the molding mold. In bulge forming, in which the work is deformed according to the forming die, there was a case where there was a gap between the pressing die and the forming die. The float mold easily follows the other mold even during molding.

The apparatus for manufacturing a turnbuckle body disclosed in Japanese Utility Model Publication No. 3-41860 has a circular pipe mounted in a superposed mold of a lower mold and an upper mold, and oil such as oil is placed in the pipe. By manufacturing the turnbuckle body in which the hexagonal column-shaped bulge is formed in the middle of the pipe by only gradually increasing the pressure after filling the fluid, the number of steps can be reduced and the turnbuckle can be reduced. The body can be mass-produced at low cost. The turnbuckle and its manufacturing method disclosed in Japanese Examined Patent Publication No. 5-42564 are formed by using a circular pipe as a raw material and bulging an axially intermediate portion of the pipe in a radial direction by internal pressure. , The circular pipe is plastically deformed to obtain the strength required for the turnbuckle.

[0013]

Problems to be Solved by the Invention Patent No. 2895748
The method for manufacturing a drive pinion spacer disclosed in Japanese Patent Laid-Open Publication No. 2003-242242 is used when a spacer is manufactured by a mechanical press, and a metal member that is pressed to expand the diameter of one end surface is processed when the excess fluid flows. Although hardening is caused to increase the strength, however, since the other end face is the material pipe itself, it does not significantly change from the hardness of the material pipe unless another step is required. Therefore, when the hardness of the end face is low on only one side as described above, abrasion is likely to progress only on the end face on the low hardness side, and as a result, a defect due to the wear of the end face is likely to occur, which is not preferable. further,
The invention disclosed in Japanese Patent No. 2895748 did not include a specific means for changing the load characteristics of the spacer for each vehicle type. In addition, considering only the spacer having a flat load-compression characteristic in the predetermined load range as the load characteristic, a means for changing the load characteristic is provided when the load characteristic other than this is required for the spacer by changing the vehicle type. Didn't. The inventions disclosed in Japanese Examined Patent Publication No. 56-4332, Japanese Utility Model Publication No. 3-41860 and Japanese Patent Publication No. 5-42564 all insert a fluid inside a substantially cylindrical work and The work was deformed by the pressure. However, these inventions are not related to the spacer for the drive pinion, and therefore ensure that both end surfaces of the spacer have sufficient hardness to prevent the end surface from being worn and troubles associated therewith, and not The purpose of the present invention is not to prevent deformation from occurring more reliably and to mold the same mold with different load characteristics.

The present invention has been made in view of the above points, and secures sufficient hardness on both end surfaces of the spacer so that the end surface is less likely to be worn and troubles associated therewith, and the inner side of the spacer is prevented. It is an object of the present invention to provide a drive pinion spacer that is more reliably prevented from being deformed and is molded from the same mold so as to have different load characteristics, and a manufacturing method thereof.

[0015]

As a means for solving the above-mentioned problems, the present invention provides a material pipe having a hardness Hv100-125 of 70-
Hydroform molding with a molding pressure of 130 MPa,
Forming the material pipe such that the central portion has a large diameter portion and both end portions have a small diameter portion, and thereafter, the large diameter portion of the material pipe is separated to manufacture two spacers having substantially the same shape. Characterize. With this configuration, the hardness of the spacer after processing becomes the required hardness Hv140 or more, and the plate thickness is also stabilized, so that the life of the bearing that abuts against the end face of the spacer is prevented from being shortened due to abrasion, and Manufacturing equipment (die, axial push punch) by making the shape easy to process
Is easier and productivity is improved.

Next, in the invention described in claim 2, in the structure described in claim 1, the end portion of the spacer is further ground by a machining allowance of 0.4 to 1.2 mm. Is characterized by. With this configuration, the contact surface with the bearing can be formed at the optimum hardness position in the hardness distribution of the end surface of the spacer formed by hydroforming, so that the end surface of the spacer can ensure the required hardness. The accuracy of the contact surface with the bearing can be improved by
Further, since the service life of the axial push punch can be extended, the correction frequency of the axial push punch is reduced.

Further, in the invention described in claim 3, in the invention described in claim 1, the material pipe is hydrolyzed so as to have a bulge portion between the small diameter portion and the large diameter portion. When forming the foam and forming the bulged portion, it is characterized in that the axial push punch is inserted up to the base of the bulged portion on the side of the small diameter portion. With this structure, it is possible to reliably prevent the spacer from protruding inward during hydroforming, so that the spacer does not deform inward in the vicinity of the bulge when the spacer is axially compressed. Therefore, it becomes easy to attach / detach to / from the shaft portion of the drive pinion.

Further, in the invention described in claim 4, in the invention described in claim 1, the load of the spacer is changed by changing the axial pressing amount by the axial pressing punch when performing the hydroform molding. It is characterized by changing the characteristics. With this configuration, it is possible to manufacture spacers having different load characteristics without changing the mold, but mainly by changing the axial push amount by the axial push punch during hydroform molding. Therefore, the same mold can be applied to different vehicle types, which improves many points that conventionally required many molds and jigs, and contributes to further efficiency of manufacturing equipment and processing steps.

Further, in the invention described in claim 5, in the invention described in claim 4, the timing of the axial pushing by the axial pushing punch is after the pipe expanding deformation of the material pipe. . With this configuration, the thickness of the spacer is effectively increased on the small diameter side by a very simple means of timing the axis pressing by the axial pressing punch, and the strength on the small diameter side is increased.

Further, in the invention described in claim 6, there is provided a spacer which is axially compressed and mounted between the two bearings of the drive pinion, the spacer being formed by hydroforming and having a small diameter portion and a large diameter portion. It is characterized in that it has a bulging portion between itself and the following conditions. (1) 7 mm <R <15 mm, (2) 1.4 <t (max) / t (min) <1.65, and 1.15 <t (max) / source tube side t (min) <1 .4, where R is the root shape radius of the outer surface of the small diameter portion of the bulging portion, t (max) is the maximum thickness of the bulging portion on the small diameter portion side, and t (min) is the bulging portion. The minimum thickness on the large diameter side and the source tube side t (min) are the minimum thickness on the small diameter side.
According to this structure, when the spacer is compressed in the axial direction, inward deformation does not occur in the vicinity of the bulging portion, so that the spacer can be easily removed without interfering with the shaft portion of the drive pinion.

According to the invention described in claim 7, in the invention described in claim 6, the hardness of the end portion of the spacer is Hv140 or more. With this structure, the end surface of the spacer is more reliably provided with the required hardness, and the accuracy of the contact surface with the bearing is improved. First, the pressure applied to the bearing is appropriately maintained to prevent problems such as oil leakage.

The drive pinion spacer and the method for manufacturing the same according to the present invention are basically constructed as described above. However, in order to make it more difficult for the end face of the product to be worn and defects caused by the wear, The hardness of the end surface of the spacer can be further improved by appropriately adjusting the pipe characteristics, molding conditions and post-processing. In addition, it is possible to more reliably prevent the occurrence of the inner deformation of the spacer by appropriately adjusting the part design, the mold shape and the molding conditions. Further, in the method for manufacturing the drive pinion spacer according to the present invention, the load characteristics of the spacer are determined by the strength balance between the small diameter side including the small diameter end and the bulging portion and the large diameter side including the large diameter end. preferable. At this time, the strength on the large diameter side is determined by the material, wall thickness, and dimensions of the material pipe used, and the material, wall thickness, and dimension of the material pipe used, and the axial push amount of the axial push pipe during hydroforming. By defining the strength on the small diameter side by this pattern and selecting the balance between the strength on the large diameter side and the strength on the small diameter side, different load characteristics of the spacer may be set for each vehicle model from the same mold.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a drive pinion spacer according to an embodiment of the present invention and a method for manufacturing the same will be described with reference to the accompanying drawings.

First, the drive pinion spacer 10 according to the embodiment of the present invention will be described. FIG. 1 is a drive pinion spacer 10 according to an embodiment of the present invention.
FIG. As shown, the spacer 10
Has a bulging portion 12 near the center of the main body, and has a small diameter end portion (small diameter portion) 11 and a large diameter end portion (large diameter portion) 13 with different diameters sandwiching the bulging portion (convex portion) 12. . In particular, a gently curved corner (curved portion) is formed between the bulging portion 12 having a large difference in diameter and the small-diameter end portion 11. However, R1 represents the root shape radius of the outer surface of the corner on the small diameter portion side, and R2 represents the root shape radius of the inner surface of the corner on the small diameter portion side. The spacer 10 has the small-diameter end portion 11 and the large-diameter end portion 13 as shown in FIG.
Since a large load is applied to the bearing 50a closer to the pinion gear 41 when abutting the pinion, the pinion 41 side (the large diameter end portion 1
This is because the inner ring and outer ring dimensions of the bearing 50a on the (3 side) are selected to be larger.

FIG. 2 shows the spacer 10 before (A) and after (B) deformation. As shown in FIG. 13, by fitting the spacer 10 on the shaft portion 40 of the reduction gear 41,
When the spacer 10 is compressed by the nut 51, elastic deformation and plastic deformation are performed as shown in FIG. 2B, and the spacer 10 is compressed by about 2 mm in the axial direction. At this time, reference numeral 1
As shown in 2 ', the bulging portion 12 of the spacer 10 having the lowest strength in the axial direction is compressed and deformed.
During this deformation, the plastic deformation amount does not return to the original, but the elastic deformation amount returns to the original, and when the load is divided from the assembled state, springback occurs by about 0.2 to 0.3 mm. 10 is a bearing 50a arranged on both sides of this,
A pressurization can be established between 50b (see FIG. 13).

Next, a method of manufacturing the drive pinion spacer 10 according to the embodiment of the present invention will be described with reference to FIGS. 3A to 3C are views showing a method of manufacturing the drive pinion spacer 10 according to the embodiment of the present invention in three stages, (A) to (C). First,
As shown in FIG. 3A, when the spacer 10 is manufactured from the material pipe 1, the diameter of the material pipe 1 to be used is made equal to the diameter of the small-diameter end portion 11 of the spacer 10 after processing. This is because hydroforming is basically a process for expanding the diameter of the material pipe 1. Therefore, by setting the diameter of the material pipe 1 before processing to the size on the small diameter 11 side, the spacer 10 can be easily processed. Is. Next, as shown in FIG. 3B, the material pipe 1 is subjected to hydroform molding from the inside to change the shape of the material pipe 1.
Then, as shown in FIG. 3C, the material pipe 1 after hydroforming is separated into two parts from the center, and both end faces thereof are subjected to a grinding process, so that one material pipe 1 is divided into two spacers. Take 2 of 10. In this way, the spacer 10 is formed by taking two products from one material pipe 1 by performing hydroforming. However, it is possible to form the spacer 10 by taking one product or more than three products. However, in the case of taking one piece, it is necessary to push the shaft while expanding the pipe on one side (the large diameter portion 13 side). In addition, when three or more pieces are formed at one time, it is necessary to give the effect of axial pushing to the products other than both ends (inside). In this case, since the plate thickness distribution of the inner product becomes constant, the quality of the formed products greatly varies. It is possible to form products of uniform quality by making the plate thickness constant in all products, but it is unlikely that they will meet the required specifications of the products.

The hydroform molding of the spacer 10 shown in FIG. 3B will be described more specifically with reference to FIG. First, as shown in FIG.
A mold 20 having an inner surface following the outer surface shape of the spacer 10.
Then, the material pipe 1 is fitted inside the mold 20. The mold 20 has a small-diameter end recess 21, a bulge recess 22, and a large-diameter end recess 23 formed on the inner surface thereof. And
The outer surface shape of the material pipe 1 is defined by these concave portions 21, 22, 23.
In order to deform the material pipe 1, the axial pressing punch 30 is inserted into the mold 20 so as to contact both sides of the material pipe 1. Outer surface of material pipe 1 and recesses 22 and 23 of mold 20
A void (gap) 24 is formed between them, and hydroforming is performed from the inside of the spacer 10 so as to allow the outer surface of the material pipe 1 to escape into this void 24. Specifically, as shown in FIG. 4B, the axial push punch 30 is attached to the material pipe 1.
Then, the filling liquid W is supplied from the conduit 39 formed in one of the two axial pressing punches 30 to the material pipe 1.
Fill inside. However, the filling liquid W is preferably water to which a rust preventive is added. Then, when the material pipe 1 is changed into a desired shape by the pressure of the filling liquid W, the axial push punch 30 is placed inside the die 20 in order to prevent excessive thinning and rupture accompanying it. Push in toward. Therefore, the material pipe 1 is pressed and compressed by the pressure of the filling liquid W and the axial pressing punch 30, and the outer surface of the material pipe 1 is depressed into the concave portions 21 and
The small-diameter end portion 11, the bulge portion 12, and the large-diameter end portion 13 are integrally formed on the material pipe 1 by deforming the material pipe 2 and 23.

As described in the prior art, in the embodiment of the present invention, the length of the spacer 10 is changed by changing the size of the material pipe 1 by performing hydroform molding without changing the mold 20. It is possible to change. Further, in the embodiment according to the present invention, it is possible to prevent the spacer 2 from projecting inward 2 by selecting the part design, the mold shape, and the molding condition. Also, select the material pipe characteristics, molding conditions and post processing,
Sufficient hardness is secured on both end faces of the spacer 10. Then, the spacer 10 having various load characteristics is manufactured from one die 20 by changing the amount of axial pressing by the axial pressing punch 30 during hydroforming, which will be specifically described later.

Here, the spacer design according to the embodiment of the present invention in which the spacer 10 is prevented from the inward protrusion 2 as shown in FIG. 14 by selecting the part design, the mold shape and the molding conditions. The manufacturing method will be described. First,
The part design will be described. In designing a part, it is necessary to optimize the shape of the part where the inward deformation occurs. Specifically, the shape of the corner R1 of the spacer 10 is optimized so as not to cause the inward deformation 2 (see FIG. 14) near the corner R1 of the spacer 10 (see FIG. 1).
This is because the corner R1 formed between the small-diameter end portion 11 of the spacer 10 and the bulging portion 12 is applied to the spacer 10 in the axial direction to compress and deform the bulging portion 12. This is because the smaller the size of R1, the larger the amount of inward deformation. Therefore, in order to prevent the corner R1 from being deformed inward, it is desirable that the size of the corner R1 be larger. Generally, if the radius of the root shape is R1> 7 mm, the inward deformation is at a level where there is almost no problem. However, the size of the corner R1 is
This is a portion that has a great influence on the load characteristics of the spacer 10 (the relationship between the load and the displacement when the parts are compressed). If it is too large, the load characteristics may be adversely affected. Therefore, the preferable range of the root shape radius R1 of the corner is 7 mm <R1 <15.
mm is desirable. It should be noted that, although it is ideal that this usage range is originally adjusted according to the size of the parts, normally, the small gear 41 (the shaft portion on the small diameter portion side) used in the differential 100 (see FIG. 13) of the vehicle is used. 40 diameter 25-35m
m), there is no problem even if the above range is applied in all cases. However, it is desirable that the larger the diameter of the shaft portion 40, the closer the root root shape radius R1 is to the upper limit of the above range.

Next, the mold shape will be described. As conditions regarding the die shape that prevents the corner R1 from being deformed inward, the die shape and the axial push punch shape become problems. However, since the mold 20 (see FIG. 4) is the shape of the part itself, if there is no problem in the design of the part, the mold 20 has no problem. On the other hand, in order to form the spacer 10 having an appropriate shape at the time of hydroforming, the shape of the axial pressing punch 30 (see FIG. 4) becomes even more important. That is, as shown in FIG. 5B, when the axial pressing punch 30 does not have a length up to the root of the bulging portion 12 on the side of the small diameter end 11 during the hydroforming (see FIG. 4) (axial pressing). (When the punch 30 is short), the small diameter end 11 of the bulging portion 12 is not backed by the axial push punch 30.
There may be an inward protrusion 2 near the root of the side. However, as shown in FIG. 5A, from the tip 31 of the axial push punch 30 to the small diameter end 1 of the spacer 10.
When the length up to the portion 33 that supports 1 is sufficiently taken (see the extension indicated by the symbol d), during hydroforming,
The axial push punch 30 can be inserted up to the base of the bulging portion 12 on the side of the small-diameter end portion 11, and the spacer 10 can be reliably prevented from protruding inward. As shown in FIG. 5B, even if the axial pressing punch 30 is short, the overhang 2 does not occur inside depending on the molding conditions.
A suitable spacer 10 can be manufactured. However, in this case, since the occurrence of the overhang 2 is not reliably prevented, the small-diameter end portion 1 of the bulge portion 12 is taken into consideration for quality control.
It is desirable to insert the push punch 30 to the base of the first side.

Next, the molding conditions will be described. Under the molding conditions, the control of the axial pressing amount of the axial pressing punch 30 is the most important. As described with reference to FIG. 4 (B), a certain amount of axial pushing is always required during hydroforming, but excessive axial pushing causes deformation of the material pipe 1 to the inside, and It is not preferable because the phenomenon of overhang or excessive thickening appears in the parts. Here, with reference to FIG. 6, the control of the axial pushing amount of the axial pushing punch 30 that does not cause the inward protrusion 2 will be specifically described. FIG. 6A is a diagram showing the spacer 10 when an appropriate amount of axial pushing is performed during hydroforming. As shown in FIG. 4, when the axial pushing punch 30 is inserted into the die 20 to increase the axial pushing, the internal pressure is low and before the bulging portion 12 is formed, the central portion of the material pipe 1 is formed. The excess thickness of the metal member is flowed toward. After the internal pressure rises to some extent and the bulging portion 12 is formed, t (ma) in FIG.
As shown in the vicinity of x), thickening occurs on the inclined surface of the bulging portion 12 on the side closer to the axial pressing punch 30 (on the small-diameter end 11 side).
When the axial pushing force is further increased, excessive axial pushing force appears as a partial increase in plate thickness together with inward deformation and overhang.
When the shaft pushing is further continued, the inward overhang 2 finally occurs as shown in FIG. 6 (B). The protrusion 2 to the inside can be considered to be on the verge of buckling, and the amount of axial pushing is considerable, but there is a sign of deformation even before this. That is, this overhang 2 is the bulge 1
Since it appears as an increase in the thickness of the inclined surface of No. 2, in the embodiment of the present invention, such deformation is prevented by setting the plate thickness within an appropriate range. In the embodiment of the present invention, the appropriate range of the plate thickness is preferably the following range. 1.4 <t (max) / t (min) <1.65 and 1.15 <t (max) / source tube side t (min) <1.4 where t (max) is swelling The maximum thickness of the small-diameter end 11 side of the portion 12, t (min) is the minimum thickness of the large-diameter end 13 side of the bulging portion 12, and the source pipe side t (min) is the minimum thickness of the small-diameter end 11 Is. t (min) and the main tube side t (min) do not necessarily have to be constant values, but since they are not easily affected by molding conditions, t (max) / t (min) and t increase as the axial push increases. (Max) / source tube side t (min) increases. At this time, if either one of them goes out of range, the amount of deformation increases. In this way, by changing the plate thickness near the bulging portion 12,
When the spacer 10 is compressed under pressure, springback can be performed near the bulging portion 12. Further, by keeping the difference in the plate thickness in the vicinity of the bulging portion 12 within an appropriate range, it is possible to prevent the inward protrusion 2 from occurring.

As described above, as a molding condition, it is necessary that the spacer 10 has no inward projection 2 (see FIG. 14) before the assembly. However,
Since the amount of change in the overhang 2 is small, it may occur that it is difficult to select acceptable products from rejected products in the production process.
However, the overhang 2 that can be seen visually is on the verge of buckling, which definitely causes deformation, which is not preferable.

Further, as the molding conditions, the small-diameter end portion 11
The radius R1 of the root shape of the outer surface on the side of the small diameter end 11 and the root shape radius R2 of the inner surface of the side of the small diameter end 11 between the bulging portion 12 and the corner must satisfy R1> 7 mm and R2> 7 mm. (See Figure 1). It is premised that the corner shape radii R1 and R2 of the corners satisfy the condition of 7 mm or more for the shape of the bulging portion 12 in the design stage, but the shape of the bulging portion 12 is increased due to the increase of the axial pushing. As shown in (B), the root shape radii R1 and R2 tend to be small. When either one of the root shape radius R1 of the small diameter side outer surface and the root shape radius R2 of the small diameter side inner surface becomes 7 mm or less, the amount of deformation increases.

Therefore, the constraint condition of the shape of the part for preventing the inward deformation is as follows. (A) 1.4 <t (max) / t (min) <1.65, and 1.15 <t (max) / source tube side t (min) <1.4, (B) before assembly In, there is no protrusion to the inside, and (C) R1> 7mm and R2> 7mm

Here, with reference to FIG. 7, an example of the measurement result of the inward deformation amount at the time of assembling the parts will be described.
In addition, the dimension of the measured spacer is 24 mm on the small diameter side.
mm, the outer diameter of the large diameter portion is 29 mm, and the maximum diameter of the bulge portion is 33 mm. The material pipe used had an outer diameter of 24 mm and a plate thickness of 1.8 mm (drawing material). Further, the deformation amount was measured by compressing the part by 2.5 mm and changing the inner diameter before and after assuming the time of assembly. As shown in FIG. 7, among the items 1 to 5, 1 satisfies all the conditions, but the other items (2 to 5) include items that cannot satisfy the conditions. From this result, it can be understood that the deformation amount increases unless all the conditions described in (A) to (C) are satisfied, and that the deformation amount decreases by approaching the appropriate range.

Next, a method of manufacturing the spacer according to the embodiment of the present invention, which secures sufficient hardness on both end surfaces of the spacer 10, will be described. The outer surface shape of the spacer 10 is obtained by the above-mentioned hydroform molding. However, in order to manufacture the spacer 10 which prevents the wear of the end surface of the product and the defects caused by the wear, the spacer 10 is made of Hv.
It must have a hardness of 140 or higher. This is because it is empirically known that when the hardness of the end surface of the spacer 10 falls below this value, inconveniences such as oil leakage occur as described in the related art. The hardness of the end surface of the spacer 10 depends on the material pipe characteristics, molding conditions and post-processing.
Determined by one condition. Hereinafter, each condition will be described in detail.

First, the material pipe characteristics will be described.
In the embodiment according to the present invention, the spacer 10 has the Hv 14
In order to have a hardness of 0 or higher, the material pipe 1 having a hardness of Hv 100 or higher is used. The material pipe 1 having a hardness of Hv100 or less can relatively increase the hardness, but it is not preferable because the possibility of achieving the required hardness (Hv140 or more) is reduced. On the contrary, when a hard material is used, it is easy to secure the required end face hardness, but the harder material has the disadvantage that the workability becomes worse. Therefore, in the embodiment according to the present invention, the material pipe 1 having a hardness of Hv100 to 125 is used as the material pipe characteristic.

Next, the molding conditions will be described. Hv1
When hydroforming is performed on the material pipe 1 having a hardness of about 00 to 125, the large diameter portion 13 side is expanded, so that the large diameter portion 13 does not require any special means, but the required hardness (Hv140 Above) can be secured. This is because the metal member under pressure causes work hardening due to fluidization of the excess thickness with hydroform molding,
This is to increase the strength. Specifically, the hardness of the large diameter portion 13 side increases within the range of Hv 140 to 160 due to work hardening. However, the small diameter portion 1 of the spacer 10
Since the diameter of 1 side is not expanded, in order to increase the hardness of the small diameter portion 11 side, a load (compression load) is applied to the end surface of the material pipe 1.
It becomes necessary to select molding conditions so as to add

In the preferred embodiment according to the present invention, as molding conditions, time, pressure, and the amount of axial pushing of the axial pushing punch 30 are appropriately controlled to secure the hardness required especially on the small diameter portion 11 side. . At this time, the molding time is generally in the range of about 5 to 15 seconds, but the hardness of the end face increases as the processing is performed in a shorter time, so it is desirable to set the time to 5 seconds or less. However, the molding time mentioned here refers to the time during which the internal pressure is applied to the material, and does not include the time required for opening and closing the mold 20 and filling the filling liquid W. The molding pressure is 7
The range of 0 to 200 MPa is general, but the hardness of the end surface increases as the pressure is reduced, so 70 to 130 MPa
A pressure of about a is desirable. Although the specific range of the axial pressing amount of the axial pressing punch 30 varies depending on the product (each product has a forming range of about 10 mm), generally, the larger the axial pressing amount is, the harder the end surface becomes. Sa rises. However, increasing the axial pushing amount increases the length of the material pipe 1 and is not economical. In practice, the middle range of the molding range is the most balanced. Further, when the axial pushing amount is further large, the end surface hardness increases, but the internal hardness tends to decrease. In this case, it is not optimal for grinding the end surface in the post processing. However, as will be described later, in the embodiment of the present invention, the load characteristic of the spacer 10 is changed by appropriately changing the axial pushing timing of the axial pushing punch 30, so the axial pushing amount of the axial pushing punch 30 is small. It is important to secure the necessary hardness on the 11 side and set this load characteristic.

Here, with reference to FIGS. 8 to 10, the influence of the molding time, the molding pressure and the axial pressing amount on the hardness distribution of the spacer 10 will be described based on the measurement results. However,
8 to 10 all show an inner diameter of 20.35 (± 0.2
5) mm, plate thickness 1.8 (± 0.18) mm STKM steel pipe (Hv115 ± 5), length 47.9 (± 0.15)
The hardness distribution on the small diameter side when the mm spacer 10 is processed under various conditions is shown. FIG. 8 shows the influence of the molding time on the hardness distribution. When two molding times of 4 seconds and 10 seconds are compared, it is shown that the shorter the molding time is, the more the end surface hardness is increased. ing. However, in any of the conditions, the position from the end of the spacer 10 is 0.4 mm to
End face hardness required in the range of 1.2 mm (Hv140 or more)
Secure. FIG. 9 shows the influence of the molding pressure (liquid pressure) on the hardness distribution. When two pressures of 80 MPa and 100 MPa are compared, the spacer 10 is
It is shown that the required end face hardness (Hv140 or more) is secured within a range of 0.4 mm to 1.2 mm from the end of the. Further, from the figure, generally, the molding pressure is 70-
The range of 200 MPa is said to be preferable, but a lower pressure of about 70 to 130 MPa indicates that the hardness of the end face can be increased within an appropriate range. Figure 1
0 indicates the effect of the axial pressing amount on the hardness distribution, and 1
When the two axial pushing amounts of 0 mm and 12 mm are compared, the position from the end of the spacer 10 is 0.4
mm-1.2 mm required end face hardness (Hv140
Above) is ensured. It should be noted that it is possible to increase the end face hardness more as the axial pushing amount increases.However, with respect to the axial pushing amount, it is observed that the hardness increases in the end face and in the range close to the end face as the axial pushing amount increases. However, since the hardness decreases rapidly, it is necessary to reduce the amount during grinding. Therefore, as described above, the molding condition in which the axial pressing amount is large is an appropriate condition when the grinding process is not performed as the post-processing. In addition, the spacer 10 with the axial pushing amount of 10 mm in FIG.
The hardness of the end face was Hv154 and the hardness of the end face on the large diameter side was Hv151 when the grinding process was performed. As a result of carrying out an actual running durability test using this spacer 10, defects such as reduction of tightening force (loosening of parts) and oil leakage did not occur. As described above, as shown in FIGS. 8 to 10, under all molding conditions, ensure the required end surface hardness (Hv 140 or more) within the range of 0.4 mm to 1.2 mm from the end of the spacer 10. Was recognized.

Next, the post processing will be described. In the preferred embodiment according to the present invention, the end surface of the spacer 10 is post-processed in consideration of the quality of the surface roughness of the product end surface.
The post-processing is to remove a part of the spacer 10 by grinding the end surface. This is because the die 20 and the axial push punch 30 have large surface roughness due to wear and damage due to repeated machining, and if the die 20 and the axial push punch 30 in this state are continuously used, the rough surface state is This is because it may be transferred to the spacer 10 and deteriorate the product quality.
Therefore, although post-processing is not necessarily required for all parts, it is desirable to post-process the end surface of the spacer 10 in order to always provide the spacer 10 of constant quality.

When post-processing is carried out, the amount of grinding processing is important for ensuring the hardness. Depending on the molding conditions,
The outermost surface has a sufficient hardness, but in order to further widen the range of molding conditions, the spacer 10 should have a hardness of 0.
It is optimal to grind 4 to 1.2 mm. Usually, the hardness distribution is 0 to 0..0 as shown in FIGS.
It tends to descend once within a range of 2 mm, rise at 0.2 to 0.4 mm, then maintain a constant value up to about 1.2 mm, and then descend again. Depending on the molding conditions, there is a case where the required hardness can be secured up to about 1.8 mm, but it is desirable to set 1.2 mm as the upper limit so that the required end face hardness can be reliably secured under a wider range of molding conditions. In addition, if the thickness is 1.2 mm or more, the material is wasted, which is not appropriate.

Therefore, according to the embodiment of the present invention, by satisfying the three conditions of the above-mentioned component design, mold shape and molding condition, the drive pinion spacer and the spacer for the drive pinion which do not generate inward deformation at the time of assembling. A manufacturing method is provided.

Further, the embodiment of the present invention makes it possible to manufacture spacers having different load characteristics from the same mold when performing the above-mentioned hydroform molding.
Hereinafter, specific means for manufacturing the spacer 10 having different load characteristics from the same mold 20 will be described.

As described with reference to FIGS. 1 and 2,
The spacer 10 has a bulging portion 12 near the center of the main body, and is deformed around the bulging portion 12 when assembled to the shaft portion 40 (see FIG. 13) of the differential gear 41 of the vehicle.
This is because when the material pipe 1 is expanded in diameter during hydroforming, the plate thickness becomes smaller than that of the small diameter portion 11 and the large diameter portion 13, so that the compressive strength when the spacer 10 is pressed in the axial direction. This is because compressive deformation occurs around the bulged portion 12 having the lowest value. Here, referring again to FIG. 1, the spacer 1
0 is divided into two sections from substantially the center, the side having the small diameter end portion 11 and the bulging portion 12 is the small diameter side a, the side having the large diameter end portion 13 is the large diameter side b, and FIGS. The respective deformation behaviors of the small-diameter side a and the large-diameter side b when the spacer 10 is pressurized and compressed will be described with reference to FIG.

FIG. 11 (A) shows the deformation behavior of the small-diameter side a when the spacer 10 is pressed and compressed, divided into two before and after pressing, which will be described with reference to FIG. As described above, when pressure is applied in the axial direction, compared to the straight portion of the small-diameter end portion 11,
It shows that the bulging portion 12 having a low strength in the axial direction is deformed as indicated by reference numeral 12 'and is crushed in the compression direction. This indicates that the strength on the small diameter side a is determined by the strength of the bulging portion 12 having the lowest compressive strength in the axial direction.
In addition, the load characteristics on the small diameter side a at this time are indicated by reference character A in FIG.
As shown in, the load abruptly increases in the initial elastic deformation region, and when plastic deformation starts, the load value decreases. FIG. 11B shows the deformation behavior of the large-diameter side b when the spacer 10 is compressed under pressure, divided into two, before and after pressure application. , 13 ', it is deformed so as to project in the direction perpendicular to the compression direction. At this time, the load characteristic on the large diameter side b behaves such that the load sharply increases in the initial elastic deformation region and the load value continues to increase thereafter, as indicated by reference character C in FIG.

Generally, the load characteristics relating to the load and the displacement of the spacer 10 are as described in lines 28 to 32 in the left column of page 2 of Japanese Patent No. 2895748.
When the nut is tightened by a predetermined amount, it is desirable that the load rises to a predetermined appropriate load range and reaches the upper limit, and then the bending is slightly bent to maintain the load close to the maximum load. There is. However, when the main body of the spacer 10 is divided into the small-diameter side a and the large-diameter side b, the load characteristics of the spacer 10 are as shown in FIG. 11 and FIG. It can be explained that it is determined by the strength balance on the large diameter side b.

Here, the strength balance between the small diameter side a and the large diameter side b will be described with reference to FIG. When the strength of the small diameter side a is made lower than the strength of the large diameter side b, the load characteristic of the spacer 10 is specified by the small diameter side a, and after the load increases and reaches the upper limit as shown by the curve A in FIG. , Descend without maintaining its maximum load. When the strength of the small diameter side a is made higher than the strength of the large diameter side b, the load characteristic of the spacer 10 is specified by the large diameter side b, and the curve C in FIG.
As shown in, the load continues to rise. When the strength on the small diameter side a and the strength on the large diameter side b are made substantially equal,
As shown by the curve B in FIG. 12, the load characteristic of the spacer 10 behaves so as to maintain the maximum load after the load rises and reaches the upper limit.

Therefore, when the load characteristics of the spacer 10 are changed for each vehicle type, the main body is divided into the small diameter side a and the large diameter side b, and the balance of strength on each side is selected to select the entire spacer 10. It is desirable to adjust the load characteristics of the vehicle to an appropriate setting for each vehicle type. Hereinafter, a method of setting the load characteristics on the small diameter side a and the large diameter side b of the spacer 10 in the case of the double picking shown in FIG. 3 will be described.

The strength of the large-diameter side b is the material pipe 1 to be used.
It is almost determined by the material, wall thickness, and dimensions of. Actually, the molding conditions at the time of hydroform molding and the shape of the mold 20 are affected, however, in the embodiment of the present invention, since it is intended to manufacture the spacer 10 having different load characteristics with the same mold, It is not premised that the mold 20 is changed, and therefore, the shape of the mold 20 is virtually unaffected. Further, the molding conditions of the hydrofoam affect the strength on the large diameter side b, but since this effect is smaller than the effect of the material, the strength on the large diameter side b depends on the material, wall thickness, and size of the material selected. It can be said that it is set. Since the material strength before and after molding is affected by work hardening, the strength difference before and after molding tends to increase as the initial strength decreases. On the other hand, in order to set the strength on the small diameter side a, it is necessary to consider not only the material, the wall thickness, and the size of the material pipe 1 to be used but also the molding conditions at the time of hydroforming. On this occasion,
As the molding conditions, the amount of axial pushing of the axial pushing pipe 30 and this pattern have a great influence. With respect to the amount of axial pushing, increasing this amount makes it possible to increase the strength on the small diameter side a. This is because as the axial pressing amount increases, the wall thickness of the bulging portion 12 that affects the strength of the small diameter side a increases, and the material flow due to the axial pressing increases, so that the influence of work hardening increases. . Regarding the axial pushing pattern, when the pushing timing of the axial pushing pipe 30 is delayed, the strength on the small diameter side a is increased as compared with the case where it is advanced. This is because when the axial pushing of the axial pushing pipe 30 is fast, the material is fed by the axial pushing before the material pipe 1 is expanded by the internal pressure, so in the case of the two-piece picking shown in FIG. 3 and FIG. 1 The thickening on the large diameter side b at the center occurs, and the strength increasing effect on the large diameter side b appears. That is, since the thickening effect by axial pushing is used on the large diameter side b, This is because the amount decreases and it becomes difficult to effectively increase the strength on the small diameter side a. On the other hand, when the axial pushing of the axial pushing pipe 30 is slow, since the pipe is expanded before the axial pushing is sufficiently performed, the axial pushing is performed after the die 20 and the material pipe 1 are brought into contact with each other, and the die is pushed. Due to the friction between the material 20 and the material pipe 1, the central large diameter side b is not thickened, and the bulging portion 12 through which the material can reach after pipe expansion is thickened. As a result, the small diameter side a
The strength of can be increased more effectively.

An example of a specific method for manufacturing the spacer 10 having various load characteristics from the same mold 20 will be described below. However, two spacers 10 are taken from one material pipe 1, and the load characteristics are shown in FIG.
It shall be divided into three patterns shown in C. Load characteristics A. Descend B. Maintenance C. Rise 1 Material strength Low Intermediate High 2-axis pushing amount Low Intermediate high 3-axis pushing timing Advance Intermediate Intermediate Delay In addition, the above explanation is the molding condition in the case of one piece manufacturing one spacer 10 from one material pipe 1. In the above, it is possible to individually set the axial pressing amounts of the small diameter side a and the large diameter side b, and it is possible to set a finer strength balance. However, in the case of single picking, as described above, it is necessary to push the shaft while expanding the pipe on the large diameter portion 13 side.

Made by the applicant of the present invention,
Three STKM steel pipes 11A, 12A, 13A having an inner diameter of 27 mm, a plate thickness of 2.45 mm, and a total length of 180 mm.
The measurement results when the spacers 10 having different load characteristics are manufactured from the same mold for the material pipes 1 of various types will be described. However, hydroform molding is 2
After individual molding, after molding, cutting at the center, end face processing was carried out to obtain a finished product. In addition, the spacer 10 after hydroforming has a total length of 70 mm and the small-diameter side a dimension is 27 m inside diameter.
m, plate thickness 2.45 mm, large diameter side b dimension is 31 mm inner diameter,
The plate thickness is 2.3 mm, the maximum diameter of the bulging portion 12 is 40 mm, and the central portion of the bulging portion 12 is 25 mm from the large-diameter end portion. The axial pushing amount was set to 10 mm on one side for all materials, and the axial pushing timing was set earlier for the material having lower strength.
The measurement result of the load characteristics after forming shows that the spacer using the STKM steel pipe 11A as a material pipe has a property close to the pattern A in FIG. 12, and the spacer using the STKM steel pipe 12A as a material pipe has a property close to the pattern B in FIG. The characteristics and the spacer using the STKM steel pipe 13A as the material pipe showed the characteristics close to the pattern C in FIG. Therefore, it was recognized that spacers having different load characteristics can be manufactured by changing the characteristics of the material used and the molding conditions without changing the mold.

It should be noted that, in the right column, lines 6 to 11 of page 3 of the above-mentioned Japanese Patent No. 2895748, the product obtained by the hydraulic press has a substantially uniform plate thickness in all parts, and therefore the maximum load is applied. When the pressure reaches, the elasticity suddenly disappears and the load decreases rapidly.Therefore, depending on the variation of the steel pipe, the tightening load of the spacer is out of the specified range, or it loses elasticity and does not act as a spacer and must be replaced. It explains that there is a lot of waste. On the other hand, in the embodiment of the present invention, when hydroforming is performed, by changing the axial pressing amount by the axial pressing punch 30, the timing of axial pressing, or the material, the same die 20 can be used. Spacer 10
It is possible to change the load characteristics of
The problems found in the conventional method of manufacturing a spacer by hydroforming as described in Japanese Patent No. 748 are overcome. Therefore, the embodiment of the present invention eliminates the waste of the manufacturing equipment by minimizing the mold, jig, etc., and also eliminates the waste of the working process, and by the relatively simple work, the spacers on both end surfaces of the spacer are removed. Sufficient hardness is ensured, wear on the end face and troubles accompanying it are less likely to occur, deformation of the spacer inside is prevented more reliably, and different load characteristics are provided from the same mold. Mold the drive pinion spacer.

[0054]

As described above, according to the invention described in claim 1, the hardness of the spacer after processing is the required hardness H.
Since v140 or more and the plate thickness is stable, the bearing that contacts the end surface of the spacer is prevented from being shortened in life due to wear, and the shape of the bearing makes it easy to process, so that the manufacturing equipment (die, axial punch) ) Is simple and productivity can be improved.

According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, in the distribution of hardness of the end surface of the spacer formed by hydroforming, the bearing is placed at the optimum position of hardness. Since the contact surface can be formed,
Since the end surface of the spacer is more reliably provided with the required hardness, the accuracy of the contact surface with the bearing can be improved, and the service life of the axial pressing punch can be extended, so that the frequency of correcting the axial pressing punch can be reduced.

According to the invention described in claim 3, in addition to the effect of the invention described in claim 1, in order to reliably prevent the spacer from inwardly projecting during hydroforming, the spacer is prevented. When the drive shaft is compressed in the axial direction, the inward deformation is not generated in the vicinity of the bulging portion, so that the drive pinion can be easily attached to and detached from the drive shaft.

According to the invention described in claim 4, in addition to the effect of the invention described in claim 1, the amount of axial pressing by the axial pressing punch during the hydroform molding is mainly performed without changing the die. By making it possible to manufacture spacers having different load characteristics, it is possible to apply the same mold to different vehicle types, improving the point that many molds and jigs were required in the past. It can contribute to the further efficiency of equipment and processing processes.

According to the invention described in claim 5, in addition to the effect achieved by the invention described in claim 4, the effect of increasing the thickness of the spacer is achieved by a very simple means of timing the axial pushing by the axial pushing punch. Can be effectively generated on the small diameter side, and the strength on the small diameter side can be increased.

Further, according to the invention described in claim 6, when the spacer is axially compressed, inward deformation is not generated in the vicinity of the bulging portion, so that it is possible to easily perform without interfering with the shaft portion of the drive pinion. It can be removed.

According to the invention described in claim 7, in addition to the effect of the invention described in claim 6, the end face of the spacer has a certain required hardness to ensure the accuracy of the contact surface with the bearing. In order to improve the
It is possible to prevent the occurrence of inconveniences such as oil leakage by maintaining the proper pressurization of the bearing without causing wear on the end surface of the spacer.

[Brief description of drawings]

FIG. 1 is a side sectional view of a drive pinion spacer according to an embodiment of the present invention.

FIG. 2 is a view showing states before and after the spacer shown in FIG. 1 is compressed under pressure, divided into (A) and (B).

FIG. 3 is a diagram showing a method of manufacturing a spacer according to an embodiment of the present invention, which is divided into three stages (A), (B), and (C).

FIG. 4 is a diagram more specifically showing the hydroform molding performed in the step (B) of FIG.

FIG. 5 relates to a manufacturing method of a spacer, showing the influence of the protrusion of the spacer to the inside due to the length of the axial pressing punch.
It is a figure which divides and shows into two forms of (A) and (B).

FIG. 6 relates to a manufacturing method of a spacer, showing the influence of the protrusion of the spacer to the inside by the axial pressing amount of the axial pressing punch.
It is a figure which divides and shows into two forms of (A) and (B).

FIG. 7 is a table showing a result of measuring an inward deformation amount when a spacer is assembled.

FIG. 8 is a graph showing the influence of molding time on the hardness distribution in the spacer manufacturing method.

FIG. 9 is a diagram showing, as a graph, the effect of molding pressure on the hardness distribution in the manufacturing method of the spacer.

FIG. 10 is a graph showing the influence of the axial pressing amount on the hardness distribution in the spacer manufacturing method.

FIG. 11 is a diagram showing the deformation behaviors of the small diameter side and the large diameter side separately when (A) and (B) when the spacer is pressed and compressed.

FIG. 12 is a diagram showing the load characteristics related to the load and displacement of the spacer, which are divided into three parts: (A) descending, (B) maintaining, and (C) ascending.

FIG. 13 is a plan sectional view and a side sectional view of a differential using a drive pinion spacer, which are divided into (A) and (B).

FIG. 14 is a view showing the front and rear states when a spacer having an inward projection is compressed under pressure, divided into (A) and (B).

[Explanation of symbols]

1 Material pipe 10 Drive pinion spacer 11 Small diameter end (small diameter portion) 12 Bulging part (convex part) 13 Large diameter end (large diameter portion) 20 mold 30 axis push punch 40 Reduction gear shaft 41 Reduction Gear (Drive Pinion) 50a, 50b bearings (taper bearings) 100 differential

Claims (7)

[Claims] 1. A material pipe having a hardness of Hv100 to 125 is hydroformed at a molding pressure of 70 to 130 MPa, and the material pipe is molded so that a central portion has a large diameter portion and both end portions have small diameter portions. After that, the large diameter portion of the material pipe is separated, and two spacers having substantially the same shape are manufactured, and a method for manufacturing a spacer for a drive pinion. 2. The end portion of the spacer is 0.4
The method for manufacturing a drive pinion spacer according to claim 1, wherein the machining is performed with a machining allowance of up to 1.2 mm. 3. The material pipe is hydroformed so as to have a bulging portion between the small diameter portion and the large diameter portion, and when the bulging portion is molded, the axial pushing punch is used to expand the material. The method for manufacturing a drive pinion spacer according to claim 1, wherein the root portion of the protruding portion on the side of the small diameter portion is inserted. 4. When performing the hydroform molding,
The method for manufacturing a spacer for a drive pinion according to claim 1, wherein a load characteristic of the spacer is changed by changing an axial pressing amount of the axial pressing punch. 5. The method of manufacturing a drive pinion spacer according to claim 4, wherein the timing of axial pushing by the axial pushing punch is after the material pipe is expanded and deformed. 6. A spacer which is axially compressed and mounted between two bearings of a drive pinion, wherein the spacer has a bulging portion between a small diameter portion and a large diameter portion by hydroforming. A drive pinion spacer characterized by having the following conditions. (1) 7 mm <R <15 mm, (2) 1.4 <t (max) / t (min) <1.65, and 1.15 <t (max) / source tube side t (min) <1 .4, where R is the root shape radius of the outer surface of the small diameter portion of the bulging portion, t (max) is the maximum thickness of the bulging portion on the small diameter portion side, and t (min) is the bulging portion. The minimum thickness on the large diameter side and the source tube side t (min) are the minimum thickness on the small diameter side. 7. The hardness of the end portion of the spacer is Hv14.
The drive pinion spacer according to claim 6, wherein the spacer is 0 or more.