JPH06191420A - Manufacture of valve sleeve - Google Patents

Abstract

PURPOSE:To provide a method to manufacture a valve sleeve which has an optimum form of blank groove efficiently in a mass production scale. CONSTITUTION:A raw material processed in a form displayed in the figure (a reserve groove may be attached) is inserted to the outer periphery of a core body which consists of an outer tube 30 and an inner core 40, for example, an ironing is applied to the whole surface of the periphery of the raw material by a punch 52 with the inner diameter same as the outer diameter of a product, and a blank groove is formed as well as the outer diameter is made in a specific outer diameter of the product. In the outer tube 30, a projecting line in the axial direction with the form reversing the blank groove of the product is provided, and a projecting line to fit to a notch of the outer tube 30 is provided to the inner core 40. By pulling out the inner core 40, the diameter of the outer tube 30 can be contracted, and the product can be pushed out easily by a knockout sleeve 54.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a single-piece valve sleeve having a blind groove which is a part of a power steering device for an automobile.

[0002]

2. Description of the Related Art Power steering devices for automobiles are
A valve that switches the hydraulic circuit according to the operation of the steering wheel is incorporated. The sleeve of this valve has a hollow cylindrical shape as a whole, and has a shape as shown in FIG. 1C in which a plurality of blind grooves which are arranged at regular intervals in the circumferential direction and extend in the axial direction are formed on the inner peripheral surface thereof. Is. As shown in FIG. 2, the blind groove is a concave groove only in the axial middle portion, and both end portions are left as portions where the groove is not engraved.

It is not easy to mass-produce such a sleeve as described above in which the inner and outer diameters and the shape and size of the blind groove meet the product specifications. For example, Japanese Patent Laid-Open No. 3-176275 introduces a valve sleeve or the like in which a groove penetrating in the axial direction is once formed and then a closed ring is fitted into both ends of the groove to close both ends of the groove. However, such a structure has a problem that the number of parts is increased and assembly is troublesome.

The invention proposed in the above-mentioned Japanese Patent Laid-Open No. 3-176275 relates to a method for manufacturing the following valve sleeve shown in FIG. That is, first, a cylindrical material 90 having a large diameter portion 91 and a small diameter portion 92 shown in (a) of FIG. 9 is made,
As shown in (b), a forging die 94 having a ridge 93 is used to form a plurality of bottomed recessed grooves 95 in the small diameter part in advance, and then as shown in (c)
This is a manufacturing method in which the end portion (upper end portion) of the plurality of concave grooves formed in the material is closed by forming the blind groove 97 by plastically deforming the meat of the upper end portion to the inner peripheral side at 96.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
Although the method of manufacturing the valve sleeve of the publication is more rational than the method before that, it still has the following problems. In other words, the most inexpensive forging equipment used in this manufacturing method is the crank press, but since this machine has a constant bottom dead center at the time of pressurization, it greatly changes when the axial length of the material changes. When pressed from the radial side, the volume difference of the pressed meat directly deforms the concave groove, and the volume of the concave groove varies, resulting in poor accuracy. If you want to improve accuracy while ignoring productivity, use as a forging equipment.
You can use a press that has a hydraulic mechanism that can keep the pressure constant, but even if you work with this press, as shown in Fig. 2 (a) (a is a plan view and b is a vertical sectional view), the blind groove The ridgeline of the boundary portion reaching a predetermined depth from the end portion has an irregular forged natural shape. Therefore, in order to secure the required volume of the blind groove, the entire length of the valve sleeve must be made longer than that of a valve sleeve having an optimally shaped blind groove as shown in Fig. 2 (b). Absent. Further, the life of the plastic working die 96 shown in FIG. 9 (c) is short, which is inconvenient for mass production.

An object of the present invention is to provide a method for efficiently manufacturing a valve sleeve having a blind groove having an optimum shape as shown in FIG. 2 (b) on a mass production scale.

[0007]

DISCLOSURE OF THE INVENTION The gist of the present invention is the following method of manufacturing a valve sleeve.

Using a cylindrical solid material, the outer diameter at one end is equal to the outer diameter of the product, the outer diameter of the central portion is slightly larger than the outer diameter of the product, and the outer diameter of the other end is slightly larger than the outer diameter of the central portion. The material is molded, and a bottomed prepared hole having the same diameter as or slightly larger than the large diameter portion of the predetermined blind groove is formed in the material from the other end side.

Further, a hole having substantially the same diameter as the small diameter portion of the blind groove is formed so as to penetrate from the one end side or the other end side to the pilot hole. Then, a core body having an axial convex strip having a shape in which the blind groove of the product is inverted is inserted into this through hole, and the outer diameter can be reduced and restored, and the raw material is punched with an inner diameter equal to the outer diameter of the product. The entire outer circumference is subjected to ironing so that the outer diameter becomes a predetermined product outer diameter and a blind groove is formed.

In the above-described method for manufacturing a valve sleeve of the present invention, an outer cylinder, which is installed as a core on the fixed side (die side) of the forging machine, and a core, which is also installed on the moving side (punch side). It is preferable to use one consisting of The above-mentioned outer cylinder has a ridge having a shape in which the blind groove of the product is inverted and a notch portion therebetween, and the core has a ridge that fits into the notch of the outer cylinder. Is.

After inserting the outer cylinder into the through hole of the material, ironing is performed by punching while inserting the inner core into the outer cylinder. After making the cylinder diameter-reducible, push out the product toward the tip of the outer cylinder and take it out.

A preliminary groove may be formed in advance in the material having the through hole. In this case, it is desirable to make the cross-sectional shape of the preliminary groove a concave shape that opens outward.

[0013]

The specific steps and effects of the method of the present invention will be described below with reference to the drawings.

First, the basic steps of the method of the present invention will be described with reference to FIG. FIG. 1 is a vertical cross-sectional view through a central axis from a material to a product in each process.

A cylindrical solid material cut into a predetermined length is
First, a bottomed prepared hole 1 shown in a-1 of FIG. 1 and a hole 2 on the left side are formed, and the outer diameter is formed in a stepwise manner. This process can be performed by upsetting, backward extrusion and forward extrusion.

Next, the bottom of the hole 1 is punched from the left side or the right side to obtain a material having a through hole 3 as shown in a-2. In this material, the outer diameter of the left end is equal to the outer diameter of the product sleeve (shown in C of Fig. 1), the outer diameter of the central part is slightly larger than that, and the outer diameter of the right end is larger than that of the central part. Mold slightly larger.

Specifically, the shaft outer diameter D ₁ at the left end is defined as the product outer diameter D
Equal to _4, the shaft outer diameter D ₃ of the central portion slightly larger than D _1, further off-axis diameter D ₂ of the rightmost further slightly larger than D _3. Further, the dimensional difference between D ₁ and D ₂ is made substantially equal to the inner diameter dimension of the same portion in each axial direction, that is, the inner diameter dimension difference between d ₁ and d ₂ . d ₁ is the diameter of the small diameter portion of the through hole 3, which is approximately the same as the diameter d ₄ of the small diameter portion of the product sleeve. d ₂ is the diameter of the large diameter portion of the through hole 3, which is equal to or slightly larger than the diameter d ₃ of the large diameter portion of the blind groove of the product (the diameter measured at the bottom of the blind groove).

In FIG. 1, b-1 and b-2 are the steps of processing the preliminary groove 4 in addition to the above processing. That is, as shown in b-1, for example, the preliminary groove 4 is formed at the same time when the hole 1 is formed by backward extrusion, and then the holes 1 and 2 are penetrated to form the shape of b-2. Outer diameter D ₃ of the central portion at this time is smaller than the outer diameter D ₃ of a-2, the other outer diameter can be the same as the case of a-2. The preliminary groove 4 will be a blind groove of the product later, but at this time, its right end is still open. The processing of the preliminary groove 4 may be performed at the same time as the processing of the hole 2, or may be performed separately from the processing of the holes 1 and 2.

Hereinafter, the materials a-2 and b-2 will be collectively referred to as "materials", but the latter will be referred to as "preformed materials" when it is necessary to distinguish them. In the claims, "one end" and "other end" correspond to the left end and the right end in each drawing of FIG.

Using the above-mentioned material, the outer diameter is adjusted to the predetermined outer diameter of the product by ironing the outer diameter portion, and at the same time, a blind groove having a predetermined shape is formed. Hereinafter, this is called a finishing process.

One of the features of the method of the present invention is that a-2 in FIG.
Alternatively, the shape and size of the material shown in b-2 and the tool (core) used in the finishing process are included. Hereinafter, each will be described in detail.

The shape and dimensions of the material a-2 or b-2 in FIG. 1 are such that after the material shape shown in FIG. 1C is formed, the required specifications can be met without cutting the outer diameter portion. It has been selected. That is, by selecting the inner diameters d ₁ and d ₂ and the outer diameters D ₁ , D ₂ and D ₃ of the same portion in the axial direction as described above, the plastic deformation can be reasonably performed and the outer diameter D ₄ and The inner diameters d ₃ and d ₄ become the dimensions of the product sleeve as they are, and the cutting for finishing can be omitted.

In the finishing step, the outer diameter of the material is ironed, thereby finishing the outer diameter to a predetermined size and at the same time finishing the blind groove into a shape satisfying a predetermined product specification. At this time, in order to accurately process the shape of the blind groove and to smoothly take out the processed product from the processing device, a core body in which the outer cylinder 30 shown in FIG. 3 and the core 40 shown in FIG. 4 are combined. To use.

FIG. 3A is a side view of the outer cylinder 30 (which may be called a die-side mandrel because it is installed on the fixed side, that is, the die side), and FIG. It is a front view. From the right end to the center, the outer cylinder 30 has the same number of ridges 31 as the blind grooves of the product sleeve and the inverted shape of the blind grooves.
And has a notch 32 into which a convex ridge 41 of a core described later is fitted from the right end to the center.

FIG. 4 is a side view of the center core 40 (which may be called a punch side mandrel because it is installed on the moving side, that is, the punch side), and FIG. 4 (b) is a front view taken along the line BB. . The center core 40 has a ridge 41 that matches the notch 32 of the outer cylinder 30.
Have. The height of this ridge 41 is between the tip of the ridge 41 and the inner circumference of the material when the material is fitted into the outer cylinder 30 and the core 40 is inserted into the outer cylinder 30 in the finishing process described below. Make sure that there is a space corresponding to the depth of the blind groove.

The finishing process using the outer cylinder 30 and the core 40 is carried out as shown in FIGS. 5 and 6. That is, the outer cylinder 30 is set at a predetermined position in the die 51, and the punch sleeve
Press 53 from the right side and press the materials a-2 and b-2 in Fig. 1 to the outer cylinder.
Fit on the outer circumference of 30. Since the taper 33 is provided in front of the ridge 31 of the outer cylinder 30, the outer cylinder 30 is reduced in diameter as the material enters, and the insertion is smoothly performed. At this time, the center core 40 is retracted to the right and is in the position shown in the upper half of FIG.

Next, the center core 40 is moved forward (moved to the left) and inserted into the outer cylinder 30 as shown in FIG. The ridge 41 of the core fits into the notch 32 of the outer cylinder 30 and is fixed in a state where the outer diameter of the outer cylinder 30 cannot be reduced. After this state, the punch 52 whose inner diameter is equal to the outer diameter of the product sleeve is advanced to the position shown in the lower half of FIG. 5, whereby the outer diameter D ₂ and D ₃ of the material is ironed. Due to this ironing, the outer diameter D _{2 at} the right end of the material and the outer diameter D _{3 at the} center part
Is reduced to the product outer diameter D ₄ . This reduced outer diameter moves in the axial center direction, fills the space between the ridge 41 of the core 40 and the material, and only the portion corresponding to the ridge 31 of the outer cylinder remains as a blind groove. become.

When a preformed material is used, when the material is fitted into the outer cylinder 30, the ridge 31 is fitted in the preliminary groove 4. Then, the reduced amount of the outer diameter D ₂ is the spare groove 4
The right end is closed, and the reduced amount of the outer diameter D ₃ fills the gap (70 in FIG. 7, which will be described later) in the outer opening of the preliminary groove, and the predetermined blind groove is completed. The advantage of using the b-2 preforming material with respect to the a-2 material of FIG. 1 is that a highly accurate blind groove can be formed.

In order to efficiently and inexpensively manufacture a valve sleeve having a plurality of blind grooves on the inner circumference, it is desirable that materials and products can be automatically conveyed in each processing step. However, when using a material with a plurality of preliminary grooves as shown in b-2 of Fig. 1, it is necessary to align the positions of the preliminary grooves with the ridges 31 of the outer cylinder in the finishing process, Difficult to do. That is, the groove width of the blind groove is usually 5/1
Since a tolerance of less than 00mm is not allowed, it is necessary to finish the groove width of the preliminary groove 4 close to the product specification dimensions.
Then, if the preformed material is displaced even slightly in the circumferential direction during automatic conveyance, it cannot be set in a predetermined position on the outer cylinder 30.

In order to solve the above problems, the spare groove 4
It is desirable that the cross-sectional shape (circumferential cross-section) of (1) is a concave shape that opens outward as shown in FIG. 7 (a), that is, a V-shape in which the opening is slightly expanded. As a result, when the preform material is fitted into the outer periphery of the outer cylinder 30 as shown in FIG. 6, even if there is some deviation in the circumferential direction, the two are fitted smoothly.

However, the required specifications of the product cannot be satisfied if the cross section of the groove remains in a V shape.

However, in the method of the present invention, since the shaft outer diameter D ₃ at the central portion of the material is made larger than the product outer diameter D ₄ ,
By the ironing process of that part, the void 70 shown in FIG.
By filling the meat with meat, it can be molded into a predetermined sharp sectional shape as shown in FIG. 7 (b).

The product sleeve is taken out as follows. That is, when processing is completed, the core 40 and the punch 52
8 and then the punch sleeve 53 is also retracted, as shown in the lower half of FIG. 8, the knockout sleeve 54 is advanced (moved to the right) to push the product sleeve to the right. The outer cylinder 30 is no longer centered inside and is hollow inside, and the taper 34 is provided at the rear end portion of the ridge 31 thereof, so that the outer cylinder 30 is radially moved along with the extrusion of the product sleeve. The product shrinks and the product is discharged smoothly.

[0034]

According to the method of the present invention, a target highly accurate blind groove as shown in FIG. 2B can be formed between the core body and the punch 52. The length L of the incomplete part of this blind groove is
Since the groove can be shortened as compared with the groove formed by the conventional method as shown in (a), the overall length of the sleeve can be shortened and an appropriate shape can be obtained.

Further, the core body is composed of the outer cylinder 30 and the center core as described above.
If configured with 40, setting of the material to be finished into the forging device and taking out of the product after finishing are extremely smooth, so automatic transfer is possible even when producing using a continuous multi-stage forging machine. Therefore, it can be manufactured at a low cost with high productivity as compared with other processing methods.

[Brief description of drawings]

FIG. 1 is an axial vertical cross-sectional view showing a material to a product sleeve for explaining a basic step of a method of the present invention.

2A and 2B are views showing a shape of a blind groove of a product sleeve, FIG. 2A being a conventional method and FIG. 2B being a method of the present invention.

FIG. 3 is a view showing an outer cylinder constituting a core body used in the method of the present invention, (a) is an axial longitudinal sectional view, and (b) is its A-
FIG.

FIG. 4 is a view showing a core that constitutes a core used in the method of the present invention, (a) is a longitudinal cross-sectional view in the axial direction, and (b) is its B-
FIG.

FIG. 5 is a vertical cross-sectional view illustrating a product finishing step of the method of the present invention, in which the upper half is before processing (a state where the punch is retracted) and the lower half is after processing (a state where the punch is advanced).

FIG. 6 is a vertical cross-sectional view illustrating an intermediate step of product finishing according to the method of the present invention.

7 (a) is a cross-sectional view showing the shape of the preliminary groove of the intermediate material in the method of the present invention, and FIG. 7 (a) is a cross-sectional view showing the shape of the blind groove of the finished product.

FIG. 8 is a vertical cross-sectional view showing a method of taking out a product after being processed by the method of the present invention.

FIG. 9 is a diagram illustrating one of conventional manufacturing methods for a valve sleeve.

[Explanation of symbols]

1: front hole, 2: rear hole, 3: through hole, 4: preliminary groove, 5: blind groove, 30: outer cylinder, 31: its convex line, 32: its notch, 33, 34: taper 40: medium Core, 41: its convex strip, 51: die, 52: punch, 53: punch sleeve, 54: knockout sleeve, 70: void 90: cylindrical material, 91: its large diameter part, 92: its small diameter part, 94: Forging die 95: concave groove, 96: die, 97: blind groove

Claims (4)

[Claims] 1. A cylindrical solid material, wherein the outer diameter of one end is equal to the outer diameter of the product, the outer diameter of the central portion is slightly larger than the outer diameter of the product, and the outer diameter of the other end is slightly larger than the outer diameter of the central portion. It is made large, and a bottomed prepared hole with the same diameter as the large diameter part of the predetermined blind groove or a diameter slightly larger than that is formed from the other end side inside the material. From the side, a hole having substantially the same diameter as the small diameter portion of the blind groove is formed by penetrating the prepared hole, and the through hole has an axial ridge having a shape in which the blind groove of the product is inverted.
Insert a core whose outer diameter can be reduced and restored, and iron the entire outer circumference of the material with a punch having an inner diameter equal to the product outer diameter to make the outer diameter a predetermined product outer diameter and form a blind groove. A method of manufacturing a valve sleeve, comprising: 2. A core body is a fixed side (die side) of a forging machine.
, And a core that is also installed on the moving side (punch side). The outer cylinder has a ridge having a shape in which the blind groove of the product is inverted and a notch portion between the ridge and the core. The core has a ridge that fits into the cutout portion of the outer cylinder, and after inserting the outer cylinder into the through hole of the material, insert the middle core into the outer cylinder. While doing the ironing process with a punch, after finishing the process, pull out the core from the outer cylinder,
2. The method for manufacturing a valve sleeve according to claim 1, wherein the outer cylinder is made in a diameter-reducible state and the product is pushed out toward the tip of the outer cylinder and taken out. 3. A preforming material having a preliminary groove corresponding to a blind groove of a product is formed on the inner periphery of the through hole, the outer cylinder is inserted into the through hole, and then the inner core is placed in the outer cylinder. Ironing process by punching while inserting, and after finishing the process, the core is pulled out from the outer cylinder, the outer cylinder can be reduced in diameter, and the product is pushed out toward the tip direction of the outer cylinder and taken out. Item 2. A method for manufacturing a valve sleeve according to item 2. 4. The method of manufacturing a valve sleeve according to claim 3, wherein the cross-sectional shape of the preliminary groove is a concave shape that opens outward.