JP2003056568A - Method of forming bearing bush fixed to inner face of boss portion of sheet metal part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of forming a bearing bush fixed to the inner face of a boss portion of sheet metal parts, for eliminating the need for high- precision working and reducing manufacturing cost. SOLUTION: A bearing bush material 18A having a flange portion 18a formed at one end is inserted at the other end into the inner face of the cylindrical boss portion 12 integrally formed on the sheet metal parts 10 with an inner face widely opened portion 12b at one end, and the boss portion is supported in a retaining hole 30a of a die 30. The bearing bush material, in which a push-in portion 35a at the end of a punch 35, is pushed at its opposite side to the flange portion is plastically deformed, so that its thickness is reduced, and its inner and outer diameters are increased and attached closely to the inner face of the boss portion; the bearing bush material is attached closely at its opposite side to the flange portion to the inner face wide opened portion of the boss portion by a punch wide opened portion 35b at the root of the push-in portion. A knock-on pin 31 in contact with the flange portion is provided in the retaining hole for supporting working thrust on the bearing bush material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a bearing bush closely fixed to an inner surface of a boss portion of a sheet metal part.

[0002]

2. Description of the Related Art For example, as shown in FIG. 5, an oil pump used in an automobile engine has a pump shaft 9 in a rotor chamber 2 formed in a casing composed of a case body 1 and a case cover 5. There is a trochoid pump provided with an inner rotor 8 and an outer rotor 7 that meshes with the inner rotor 8. When the inner rotor 8 is rotated via the pump shaft 9, the plurality of working chambers P formed between the tooth portions of the rotors 7, 8 meshing with each other move in the circumferential direction while changing their volumes, The working fluid is sucked into the working chamber P from the suction passage 4a through the suction port 3a, and is discharged from the discharge passage 4b through the discharge port 3b. Both the conventional case body 1 and the case cover 5 are made of aluminum die-cast, and a bearing surface for bearing a steel pump shaft 9 is formed on the inner surface of the boss portion 5a of the case cover 5, and the rotors 7, 8 In order to keep the pressure balance, suction surfaces 6a and discharge ports 6b having the same shape are formed on the abutting surface at positions corresponding to the suction port 3a and the discharge port 3b of the case body 1, respectively.

[0003]

Since the case cover 5 according to the prior art as described above is made of die-cast and the joint surface with the case body 1 and the bearing surface are processed, both the material cost and the processing cost are high. . As a means of reducing this material cost, it is conceivable to use a steel plate press-formed product for the case cover, but since the pump shaft and the boss portion that forms the bearing surface that supports this are both made of steel, There is a problem that seizure occurs between the bearing surfaces and durability deteriorates. To solve this problem, a bearing bush made of metal that does not seize to the pump shaft different from the case cover may be press-fitted and fixed to the inner surface of the boss portion. Since it is necessary to process the outer surface of the bush with high precision, there is a problem that the processing cost increases. Such a problem exists not only when the case cover of the trochoid pump is made of sheet metal, but also when the bearing bush is fixedly formed on the inner surface of the boss portion of the sheet-metalized component for cost reduction.

According to the present invention, in order to form the bearing bush closely fixed to the inner surface of the boss portion of the sheet metalized part, it is not necessary to machine the inner surface of the boss portion and the outer surface of the bearing bush with high precision. The purpose is to solve each of these problems.

[0005]

A method of forming a bearing bush fixed to the inner surface of a boss portion of a sheet metal part according to the present invention is a cylindrical shape integrally formed with the sheet metal part and having an inner surface expanded portion at one end side. Insert the cylindrical bearing bush material made of a metal material different from that of the sheet metal part and having a flange at one end from the side opposite to the side where the inner surface expansion is formed, A push-in portion having an outer diameter greater than a value obtained by subtracting twice the wall thickness of the bearing bush material from the inner diameter of the boss portion and smaller than the inner diameter of the boss portion and having a punch expansion portion formed in the root portion, It is pressed into the inner surface of the bearing bush material from the side opposite to the side where the flange is formed, and the bearing bush material is plastically deformed so that its wall thickness decreases and the inner and outer diameters increase, and it makes close contact with the inner surface of the boss. And bearing bush It is characterized in that to form the bushing expanding portion which is in close contact with the inner surface expanding portion of the boss portion to the other end of the shoe material.

The cylindrical bearing bush material inserted into the inner surface of the cylindrical boss portion integrally formed with the sheet metal part is expanded and plastically deformed by the pushing portion at the tip of the punch pushed into the inner surface to be plastically deformed to the inner surface of the boss portion. While being closely attached to
A bush expanding portion that is in close contact with the inner surface expanding portion of the boss portion is formed on the side opposite to the flange portion, and the bearing bush is closely fixed to the inner surface of the boss portion of the sheet metal part.

In the method of forming the bearing bush fixed to the inner surface of the boss portion of the sheet metal component according to the present invention, it is preferable that the sheet metal component is supported by a die having a holding hole into which the boss portion is inserted.

The method of forming the bearing bush fixed to the inner surface of the boss portion of the sheet metal part according to the present invention is a method in which the bearing is inserted into the holding hole in a state where all or most of the boss portion is inserted into the holding hole. The push-in portion of the punch that contacts the flange portion of the bushing material supports the processing thrust applied to the bearing bushing material, and after retracting the punch, moves toward the punch side to push out the boss portion from the holding hole. It is preferable to provide.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a method for forming a bearing bush fixed to the inner surface of a boss portion of a sheet metal part according to the present invention will be described below with reference to FIGS. In this embodiment, the method of the present invention is applied to sheet metalization of the case cover of the trochoid pump shown in FIG.

First, the case cover (sheet metal part) 10 and the bearing bush material 18A will be described. 2 and 3
As shown in FIG. 3, the case cover 10 as a whole is composed of a flat plate portion 11 and a cylindrical boss portion 12 projecting from the central portion to one side. This boss 12
The plate portion 11 integrally formed with is formed by a series of deep drawing processes from a single steel plate and includes a plurality of processes. Is formed with an inner surface expanded portion 12b having an arcuate cross-sectional shape that spreads outward. As with the case cover 5 of the prior art shown in FIG. 5, on the surface of the plate portion 11 opposite to the side where the boss portion 12 projects, at positions corresponding to the suction port 3a and the discharge port 3b of the case body 1,
A shallow suction port 13a and a discharge port 13b having a corresponding shape are formed. Also, the plate portion 11
A shallow recess 14 is formed on the back surface of the device except the edge 15 and the ports 13a and 13b. The ports 13a and 13b and the recess 14 are formed by embossing after deep drawing. Further, mounting holes 11 a for bolting the case cover 10 to the case body 1 are provided at four corners of the plate portion 11.

The bearing bush material 18A made of a metal material different from that of the case cover 10 is formed in a cylindrical shape thinner than the boss portion 12 as shown in FIG. 2 by deep drawing so that a flange portion 18a is formed at one end. It is molded, and the length of the flange portion 18a is smaller than the wall thickness of the boss portion 12. The metal material used for the bearing bush material 18A is suitable for bearing the steel pump shaft 9 (see FIG. 5) such as brass and aluminum. This bearing bush material 18A can be inserted into the inner surface 12a of the boss portion 12 from the side opposite to the side on which the inner surface expanded portion 12b is formed until the flange portion 18a abuts on the tip surface of the boss portion 12 (see FIG. 1). .

Next, an apparatus for forming the bearing bush 18 by fixing the bearing bush material 18A in the boss portion 12 of the case cover 10 will be described with reference to FIG. A holding hole 30a into which the boss 12 of the case cover 10 is inserted with a slight gap is formed in the die 30 attached to the die holder 20 fixed to the bed of the press machine.
The protruding pin 31 is slidably fitted in the holding hole 30a. As shown in FIG. 1, the lower end is the die holder 2
0, the push-out pin 3 at the lowest position in contact with the upper surface of 0
The distance between the top surface of the die 1 and the top surface of the die 30 is determined by the length of protrusion of the boss portion 12 from the back surface of the plate portion 11 and the flange portion 18.
It is equal to or slightly smaller than the sum of the thicknesses of a. The protrusion pin 31 is urged upward from the die holder 20 by a relatively weak force by a spring 32 wound around a small diameter portion 31a formed in the lower half portion. The guide hole 20a formed in the die holder 20 coaxially with the holding hole 30a is provided with an ejector rod 21 that pushes the protruding pin 31 upward at a predetermined timing.

A punch 35 is mounted coaxially with a holding hole 30a of a die 30 on a punch holder 25 fixed to a slide of a press machine which moves up and down with respect to a bed. The punch enlarging portion 35 having an arcuate cross-sectional shape corresponding to the inner surface enlarging portion 12b is formed on the entire circumference of the root portion of a slightly smaller-diameter cylindrical pushing portion 35a formed coaxially at the tip end portion of the punch 35.
b is formed, and a rounded chamfer is formed on the entire circumference of the front end of the pushing portion 35a so that the pushing into the bearing bush material 18A is not hindered.

A product retainer 36 having a guide hole 36a slidably fitted in a large diameter portion of the punch 35 excluding the pushing portion 35a is slidably guided in a support hole 25a of a punch holder 25. It is guided and supported by a suspension rod 37 (only two are shown). This product retainer 36 is provided with a punch holder 25 so that each suspension rod 37 can be wound.
In the free state shown in FIG. 1, the heads 37a at the upper ends of the suspension rods 37 abut against the outer edge of the upper ends of the support holes 25a in the free state shown in FIG. It is held parallel to the upper surface of the die 30. The pushing portion 35a at the tip of the punch 35 in this state
In the illustrated embodiment, the relationship between the
Although the tip of the former and the lower surface of the latter are made to coincide with each other, the tip of the former may be made to project a little below the lower surface of the latter, or conversely, the tip of the former may be made into the guide hole 36 of the latter.
It may be located within a. Spring 38 is much stronger than spring 32.

As for the dimensional relationship among the boss portion 12 of the case cover 10, the bearing bush material 18A, and the holding hole 30a of the die 30, the boss portion 12 can be lightly inserted into the holding hole 30a. The boss portion 12 should be lightly insertable. The outer diameter of the pushing portion 35a at the tip of the punch 35 is larger than the value obtained by subtracting twice the thickness of the bearing bush material 18A from the inner diameter of the boss portion 12, and the boss portion 1
It is smaller than the inner diameter of 2 and therefore larger than the inner diameter of the bearing bush material 18A. To give an example of these dimensions,
The holding hole 30a of the die 30 has an inner diameter of 23.50 mm, and the boss 12 has an outer diameter and an inner diameter of 23.00, respectively.
mm and 18.05 mm, bearing bush material 18A
The outer and inner diameters of 18.00 mm and 16.
The outer diameter of the pushing portion 35a is 16.20 mm.

Next, a method of forming the bearing bush 18 on the inner surface 12a of the boss portion 12 according to this embodiment will be described. First, in a state where the punch holder 25 supporting the punch 35, the product retainer 36, etc. is separated from the die 30 upward, as shown in the lower half of FIG.
Bearing bush material 18A in the boss portion 12 from the side opposite to
The boss 12 holds the case cover 10 in which the
It is placed on the die 30 so that it is inserted into the 0a. In this state, the flange portion 18a of the bearing bush material 18A
The case cover 1 is brought into contact with the top surface of the protrusion pin 31.
0 and the weight of the bearing bush 18 cause the spring 32
Is bent, and the lower end surface of the protruding pin 31 is attached to the die holder 20.
Abutting on the upper surface of the case cover 10 and the plate portion 11 of the case cover 10.
The back surface of is lightly contacted with the upper surface of the die 30 or slightly floated.

Then, the punch holder 25 supporting the punch 35 and the product retainer 36 is lowered toward the die 30 to bring the lower surface of the product retainer 36 into contact with the surface of the case cover 10 and further lower it. Due to the descending after the contact, the pushing portion 35a is pushed into the bearing bush material 18A to give a machining force in the axial direction to the bearing bush material 18A, and the spring 38 bends so that the product retainer 36 is pushed over the surface of the plate portion 11 considerably. Presses elastically with force. When the plate portion 11 is slightly floated, the case cover 10 is pushed down by the spring 38 after the product retainer 36 is contacted, and the flange portion 18a of the bearing bush material 18A contacts the tip end surface of the boss portion 12. To be done.

Since the outer diameter of the pushing portion 35a is larger than the inner diameter of the bearing bush material 18A, the pushing portion 35a
The bearing bush material 18A is pushed and spread by pushing in a, and the outer surface of the bearing bush material 18A is the inner surface 1
The diameter of the boss portion 12 is increased by coming into contact with the 2a. Boss part 1
No. 2 is only expanded from the inside, and since the outside diameter does not become larger than the inside diameter of the holding hole 30a, it is only elastically deformed in the radial direction. On the other hand, the pushing portion 3
The outer diameter of 5a is from the inner diameter of the boss portion 12 to the bearing bush material 1
Since it is larger than a value obtained by subtracting twice the wall thickness of 8A and smaller than the inner diameter of the boss portion 12, the bearing bush material 18A has its outer peripheral surface abutted against the inner surface 12a of the boss portion 12 and the expansion thereof is restricted. The peripheral surface is widened by the tip of the pushing portion 35a, and at the same time, it is squeezed in the axial direction to reduce the wall thickness, which causes a viscous flow inside the material of the bearing bush material 18A, thereby deforming the bearing bush material 18A. Is a plastic deformation. The bearing bush material 18A tries to move in the axial direction with respect to the boss portion 12 by the axial machining thrust when the pushing portion 35a is pushed, but since the flange portion 18a is in contact with the upper surface of the protruding pin 31, the boss Part 12
On the other hand, the bearing bush material 18A does not shift in the axial direction.

Shortly before the push-in portion 35a further descends and its tip comes into contact with the upper surface of the push-out pin 31, the punch expanding portion 35b at the base of the push-in portion 35a is moved to the flange portion 1.
The other end of the bearing bush material 18A on the opposite side of 8a is started to spread. If the tip of the pushing portion 35a contacts the upper surface of the protruding pin 31, the bearing bush material 18A
Is completed, the bush 18 is brought into close contact with the inner surface 12a of the boss portion 12, the flange portion 18a at one end is brought into contact with the tip end surface of the boss portion 12, and the other end is brought into close contact with the inner surface expanded portion 12b. The bearing bush 18 having the expanded portion 18b is formed.

Next, if the punch holder 25 is retracted upwards, the case cover 10 will move to the spring 3 at the beginning of the backward movement.
Since the pressing portion 35a is pressed against the die 30 by the biasing force of 8, the pushing portion 35a is pulled out from the bearing bush 18 fixed to the inner surface of the boss portion 12, and the bearing bush 18 is fixed to the inner surface 12a of the boss portion 12 on the die 30. The removed case cover 10 is left. Then, when the punch holder 25 is sufficiently retracted, the ejector rod 21 is operated to push the protruding pin 31 upward, push the boss portion 12 out of the holding hole 30a, and take out the case cover 10. Thereby, as shown in FIG. 4, the case cover 10 in which the bearing bush 18 is fixed to the inner surface 12a of the inner surface expanded portion 12b is obtained.

As described above, when the pushing portion 35a is pushed in, the boss portion 12 is elastically deformed in the radial direction, while the bearing bush material 18A is machined to form the bearing formed on the inner surface of the boss portion 12. Since the bush 18 is plastically deformed into its size and shape, the boss portion 12 springs back and contracts by pulling out the pushing portion 35a, but the bearing bush 18 itself does not contract.
Therefore, the contact between the boss portion 12 and the bearing bush 18 is not loosened by pulling out the pushing portion 35a.

According to the above-described embodiment, the bearing bush material 18A inserted into the inner surface 12a of the boss portion 12 of the case cover 10 has the pushing portion 3 pushed into the inner surface thereof.
The boss portion 12 is squeezed and plastically deformed by the tip portion of 5a.
Since the bearing bush 18 is closely attached to the inner surface 12a of the boss portion 12, the inner surface 12a of the boss portion 12 and the bearing bush material 18A
The outer surfaces of the sheets are firmly pressed against each other even when pressed. A flange portion 18a that engages with the tip of the boss portion 12 is formed at one end of the bearing bush 18, and a bush expansion portion 18b that is in close contact with the inner surface expansion portion 12b of the boss portion 12 is formed at the other end. Since it is formed, even if the adhesion force between the inner surface 12a of the boss portion 12 and the bearing bush 18 is insufficient, there is no possibility that the boss portion 12 and the bearing bush 18 are displaced in the axial direction by the external force in the axial direction. . In this way, the inner surface 12a of the boss portion 12 and the outer surface of the bearing bush material 18A are not subjected to any special processing, and the inner surface 1 of the boss portion 12 is
Since the bearing bush 18 fixed to 2a can be formed, the manufacturing cost can be reduced.

Further, the inner diameter of the bearing bush 18 fixed to the inner surface 12a of the boss portion 12 is determined by the pushing portion 35 of the punch 35.
The bearing bush 1 has a smaller value than the outer diameter of a by a minute dimension corresponding to the spring back of the boss portion 12.
The dimensional accuracy of the inner diameter of 8 is relatively high. Therefore, even when finishing of the inner diameter of the bearing bush 18 is required, finishing can be performed only by relatively simple processing such as reaming.

In the above-described embodiment, the punch 35 is used.
Bearing bush material 18A inserted into the boss portion 12 by inserting and supporting the boss portion 12 of the case cover 10 into the holding hole 30a formed in the die 30 coaxially with the pushing portion 35a.
The push-out pin 31 is provided in the holding hole 30a for abutting the flange portion 18a to support the processing thrust and for pushing out the boss portion 12 after processing. In this way, the boss portion 12 is positioned with respect to the pushing portion 35a. Since the precision is improved, the pushing portion 35a is prevented from being biasedly pushed into the bearing bush 18, the precision of the radial position of the bearing surface of the bearing bush 18 is improved, and the bearing bush material 18A is pushed when pushing the pushing portion 35a. Since there is no possibility that the shaft is displaced from the boss portion 12 in the axial direction, the bearing bush 18
It is possible to obtain each effect that the positioning accuracy in the axial direction is improved, and that the sheet metal component can be easily taken out after the bearing bush is fixed to the inner surface of the boss portion. However, according to the present invention, the flange portion 18a of the bearing bush material 18A inserted into the boss portion 12 is directly brought into contact with the upper surface of the die 30, or a holding hole having a bottom is formed in the die 30 to form the boss portion 12 in this holding hole. The bearing bush material 18A may be inserted so that the flange portion 18a of the bearing bush material 18A is brought into contact with the bottom surface of the holding hole. In the former case, the effect of improving the axial positioning accuracy of the bearing bush 18 is obtained. In the latter case, in addition to this, the effect of improving the accuracy of the radial position of the bearing surface of the bearing bush 18 can be obtained.

In the above embodiment, the inner surface widened portion 12
Although b has been described as an example in which it is formed on the plate portion 11 side of the boss portion 12, the present invention is carried out by forming the inner surface expanded portion 12b on the tip side of the boss portion 12 opposite to the plate portion 11. You can also

[0026]

As described above, according to the present invention, the bearing bush material is plastically deformed so as to be in close contact with the inner surface of the boss portion of the sheet metal part and the inner surface expanded portion of the boss portion on the side opposite to the flange portion. Since a bush expansion part that is closely attached to the inner surface of the boss of the sheet metal part is fixed to the inner surface of the boss, the inner surface of the boss and the outer surface of the bearing bush material are the inner surface of the boss even if pressed. The bearing bush attached to is securely fixed in close contact without the risk of movement, and the manufacturing cost can be reduced. Further, since the bearing bush can be made of a metal material suitable for a shaft to be supported differently from the sheet metal part, seizure with the shaft will not occur and durability will not deteriorate.

According to the sheet metal component supported by the die having the holding hole into which the boss portion is inserted,
Since the positioning accuracy of the boss portion with respect to the push-in portion of the punch is improved, the accuracy of the radial position of the bearing surface of the bearing bush is improved.

Further, in the holding hole of the die, the punching portion of the punch comes into contact with the flange portion of the bearing bush material to support the processing thrust applied to the bearing bush material, and after the punch retreats, moves toward the punch side. With the push-out pin that pushes the boss portion out of the holding hole, when the punching portion of the punch pushes the bearing bush material into the inner surface of the boss portion and the inner surface expansion portion to form a bearing bush material, Is not displaced in the axial direction with respect to the boss portion, and the boss portion is pushed out from the holding hole after processing, so that it is easy to take out the sheet metal part after the bearing bush is fixed to the inner surface of the boss portion.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view illustrating an embodiment of a method of forming a bearing bush fixed to an inner surface of a boss portion of a sheet metal component according to the present invention.

FIG. 2 is a sectional view of a sheet metal part (case cover) and a bearing bush material used in the embodiment shown in FIG.

FIG. 3 is a plan view of the sheet metal component shown in FIG.

FIG. 4 is a cross-sectional view of a sheet metal part to which a bearing bush obtained according to the embodiment shown in FIG. 1 is fixed.

FIG. 5 is a vertical sectional view of a trochoid pump including a case cover according to the related art.

[Explanation of symbols]

10 ... Sheet metal parts (case cover), 12 ... Boss part, 12
a ... inner surface, 12b ... inner surface expanded portion, 18 ... bearing bush,
18A ... Bearing bush material, 18a ... Flange portion, 30
... Die, 30a ... Holding hole, 31 ... Protrusion pin, 35
... punch, 35a ... pushing part, 35b ... punch expanding part.

Claims (3)

[Claims] 1. A cylinder having a flange portion formed at one end made of a metal material different from that of the sheet metal component on the inner surface of a cylindrical boss portion integrally formed with the sheet metal component and having an inner surface expanded portion at one end side. -Shaped bearing bush material is inserted from the side opposite to the side where the inner surface expanded portion is formed, and the value is obtained by subtracting twice the wall thickness of the bearing bush material from the inner diameter of the boss that is provided at the tip of the punch. A pushing portion having a larger outer diameter than the inner diameter of the boss portion and having a punch expanding portion formed in the root portion is pushed into the inner surface of the bearing bush material from the side opposite to the side where the flange portion is formed. , The bearing bush material is plastically deformed so that the wall thickness is reduced and the inner diameter and outer diameter are increased so that the bearing bush material is brought into close contact with the inner surface of the boss portion, and the inner surface of the boss portion is expanded at the other end portion of the bearing bush material. Stick to the open area A method of forming a bearing bush which is secured to the inner surface of the boss portion of the sheet metal part, characterized in that to form the bushing expanding portion has. 2. A method of forming a bearing bush fixed to an inner surface of a boss portion of the sheet metal part according to claim 1.
A method of forming a bearing bush fixed to an inner surface of a boss portion of a sheet metal part, wherein the sheet metal part is supported by a die having a holding hole into which the boss part is inserted. 3. A method for forming a bearing bush fixed to the inner surface of a boss portion of the sheet metal part according to claim 2,
The machining thrust applied to the bearing bush material by the punching portion of the punch by abutting the flange portion of the bearing bush material in a state where all or most of the boss portion is inserted in the holding hole. And a push-out pin that pushes the boss portion out of the holding hole by moving toward the punch side after the punch retreats and is fixed to the inner surface of the boss portion of the sheet metal part. Method for forming a bearing bush.