JP2001523576A - Method and apparatus for manufacturing an integrated casing for hydraulic steering - Google Patents

Abstract

The invention comprises a casing section for accommodating a steering transmission having a pinion and a rack section, and a casing section following this casing section for arranging a hydraulic steering aid. The present invention relates to a method for manufacturing an integral casing for hydraulic steering. According to the present invention, a cold-deformable hollow formed body as a starting product is sealed on one side or both sides in the vicinity of a region to be deformed by internal high pressure, and after applying internal high pressure, combined into at least one region. A controlled internal high pressure / reverse drawing method, in which the axially controlled feed of the material is carried out, and in some cases internal high pressure / correction, and then correction of the area without internal high pressure and / or Or drawing and / or stretching, and after this main deformation, a local deformation may be performed in some cases, followed by finishing by mechanical final processing. The invention further relates to an apparatus for performing the method, comprising a die, a clamping and feeding unit and a sealing element for closing the hollow body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The invention relates to a method for producing an integrated housing for hydraulic steering of the type described in the preamble of claim 1.

According to the prior art, it is known to manufacture such a hydraulic steering wheel from a two-part casing. The casing consists of a cylinder tube with welded pipe pieces for hydraulic steering and a casing part for accommodating the steering gear and the hydraulic control valve. Cylinder tubes are usually manufactured from deformed and / or machined tubes. This tube has a piece and / or
Alternatively, the holding thin plate is fixed. Said casing part usually consists of aluminum die-cast. The advantage of the overall structure is that the structure of the hydraulic cylinder is small. The disadvantage is that the press connection is very laborious and expensive to manufacture. There are also additional sealing points.

It is known to manufacture casings for hydraulic steering as one-piece casings made of aluminum die-casting. It is an obvious advantage that the assembling effort is reduced. Disadvantages include high material usage, large construction size, cumbersome tools, and thus high tool costs. In addition, high manufacturing costs due to the necessary cutting of the cylinder running surface are also important.

[0004] The object of the present invention is to provide an integrated casing for hydraulic steering, which has a small weight and space and can be manufactured in a short time, while maintaining the advantages of the integrated casing. It is to provide a method for manufacturing.

[0005] This problem is solved by the features of claim 1 starting from the generic concept of claim 1. Advantageous methods and devices for carrying out these methods are described in claim 2 and the following.

The essence of the invention lies in the use of a combination of selected method steps in producing an integrated casing for hydraulic steering. First, the seal on one or both sides of the hollow body is near the area of the hollow body that is to be deformed by the internal high pressure, and not just at the ends, as is customary heretofore. Secondly, the wall reduction in the critical deformation zone is kept small, since the internal high-pressure deformation process takes place with the material being fed back in a controlled axial direction.
Another feature of this method is that a sealing member can be used to draw or stretch a predetermined area in or out. The above steps are supplemented by the associated reverse drawing method. After the various deformations, a mechanical finishing takes place, which is significantly reduced compared to an integrated die-cast casing.

[0007] The following advantages are obtained when using the selected method steps in combination with the present invention. No assembly is required since an integral casing is manufactured. The reduced wall thickness in a given area results in reduced weight and a compact configuration. A compact configuration requires a small required configuration space, which is an important aspect in a narrowed space state in a recent automobile structure. The built-in reverse drawing allows the inner contour to be produced as desired. The closing force for the die is reduced. This is because the sealing member is positioned as desired in the vicinity of the region to be deformed, so that the entire portion does not have to be exposed to the internal high pressure. Overall, such a method makes it possible to reduce the production time for producing the integrated casing. Since the one-piece casing has no joints, a relatively high stiffness is obtained as a whole and no additional sealing members are required.

[0008] The apparatus used to carry out the method comprises:
It has ring connecting elements separated by radially extending webs. This ring-coupling element cooperates with another ring-coupling element having a tongue-shaped element, which is connected to the feed unit. By the cooperation of the two ring joining elements, the ring joint can be closed continuously. Such an arrangement can
Important for controlled axial backfeed. Because of this, the sealing points move together and the split ring joint has sufficient support via the web, so that the material of the hollow molding under internal high pressure is the ring joint element Cannot flow into the gap between the webs. The sealing point itself is formed by the ring already described above and a mandrel which is fixed to the feed unit and can be inserted into the hollow molding. To this end, the ring has an inner profile that matches the mandrel. For the reverse drawing method, a reverse drawing unit is arranged in a die type region where an internal high pressure is applied to the hollow molded body. The reverse throttling unit has a piston, which is slidable in a die-shaped notch. The sliding of the piston preferably takes place transversely to the longitudinal axis of the hollow body.

[0009] In another configuration, the piston of the reverse throttle unit may be surrounded by a ring piston. The ring piston can be slid independently of or independent of the piston by the so-called piggyback method. The mandrel cooperating with the ring has a head section and a transition section following or separate from the head section. In this transition section, a tensioning element or a tensioning / pressing element having a reduced diameter is fixed. Preferably, the tensioning and pressing element is formed as a rod. A tongue-like element extending axially from the ring is circumferentially positioned so as to exactly face each gap between the webs of the ring joining element.

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

An apparatus formed according to the present invention for performing the method is shown in FIG.
FIG. 2 is a cross-sectional view. The main elements of this device are the die dies 1, 2 consisting of two die halves. In the die-shaped end face region located here on the right-hand side, a ring-joining element divided by radially extending webs 30, 31 (FIG. 2) is arranged in each of the die halves 1,2. Alternatively, the ring connection element can be formed as an integrated component of each die half 1, 2, or as a separate insert. A ring 5 is operatively connected to the ring connection element. A tongue piece 6 extends from the ring 5 in the axial direction (FIG. 2). In this case, the tongue 6 forms another ring connecting element which is formed complementary to the gap between the webs 30, 31. The ring 5 is positioned with respect to the ring joining element in such a way that the tongue 6 exactly faces the gap between the webs 30, 31 so that when the ring 5 moves in the direction of the die, this gap will Closed continuously. A dashed line is shown in the upper die half in the region of the ring 5 to demonstrate the fit of the tongue 6 into the gap between the webs 30,31. The dashed line on the left side in the drawing indicates the web 30 as an invisible main body edge.
, 31, and the broken line located on the right side in the drawing indicates the axial start end of the tongue piece 6 as an invisible main body edge. The ring 5 is, for example, a rod 7
, 8 to a tightening and feeding unit 9. A rod 12 is fixed to the clamping and feeding unit 9 in the middle, and a front end region of the rod 12 is connected to a mandrel 21. The mandrel 21 has a head section 10, which in this embodiment is formed cylindrically, and a transition section 11 connected to a rod 12. In the notch 13 of the lower die half 2, a reverse drawing unit 14 is arranged. The reverse throttle unit 14 mainly includes a central piston 15 and a ring piston 16 surrounding the piston 15. The two pistons 15, 16 are slidable independently of one another, for example. For example, in this device, a hollow molded body 17 to be deformed is inserted. The sealing on the left side is performed by a seal plunger 18 entering the die. The seal plunger 18 has a hole 20 for filling the hollow chamber 19.

A method for manufacturing an integrated casing for a hydraulic steering according to the present invention has the following working steps.

As a starting product, a hollow molding 17 is inserted into a die having two die halves 1, 2, and the die is closed by a pressing device (not shown). The open end located on the left side of the hollow molding 17 is closed by inserting a sealing plunger 18. The right side is further sealed internally rather than at the end. For this purpose, the mandrel 21 is inserted into the hollow molding 17 by the tightening and feeding unit 9. The right end region of the hollow molding 17 is retracted by inserting the ring 5. For this purpose, the ring 5 has a corresponding inner contour. The movement of the ring 5 is performed independently of the movement of the mandrel 21. By pulling the mandrel 21 back somewhat towards the formed step 22, the required seal is obtained on this side. Through the hole 20 of the seal plunger 18, the hollow chamber 19 of the hollow molded body 17 is formed.
Is filled with a fluid. Next, a predetermined deformation of the hollow molded body 17 is performed by an inner high-pressure deformation process with controlled axial backward feeding. The dash-dot line indicates the formation of the outward bulge 23 in the upper die half 1. Axial retraction of the material is effected via the seal plunger 18 and / or by the movable mandrel 21 / ring 5 sealing member. Same fixed, reverse drawing unit 1
4 achieves the desired integral molding of the branch. The preload for sealing between the mandrel 21 and the ring 5 is reduced by sliding the mandrel 21 slightly forward. By returning the seal units 5 and 21, the end region of the hollow molded body 17 located on the right side is extended. Ring 5 at specified position
Is removed and the wall in this area is pulled outward without reduction by pulling the mandrel 21. The seal plunger 18 is returned, the dies 1 and 2 are opened, and the deformed parts are removed.

FIG. 3 better illustrates the individual deformation steps performed in this device. In the part located on the left side of the drawing, a spherical outer bulge 23 produced by an internal high-pressure / deformation process and an inner bend 2 by the reverse drawing unit 14 on the opposite side
4 is shown. The end region 25 located on the right-hand side extends to an end section 26 having a starting wall thickness. After removing the deformed part from the die,
Further minor deformations are made, for example, by shaping the grooves and then performing mechanical edge machining. Since this is not the core of the present invention, the description and illustration of the following method steps are omitted.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an apparatus formed according to the present invention for performing a method.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a longitudinal sectional view of the integrated casing after deformation.

[Explanation of symbols]

1,2 die half, 5 ring, 6 tongue, 7,8 rod, 9
Tightening / feed unit, 11 transition section, 12 rod, 13 notch,
14 reverse drawing unit, 15 piston, 16 ring piston, 17
Hollow molded body, 18 seal plunger, 19 hollow chamber, 20 holes, 21
Mandrel, 22 steps, 23 outward bulge, 24 inward bend, 2
5 end section, 26 section

[Procedural Amendment] Submission of translation of Article 34 Amendment of the Patent Cooperation Treaty

[Submission date] September 6, 1999 (September 9, 1999)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0003

[Correction method] Change

[Correction contents]

It is known to manufacture casings for hydraulic steering as one-piece casings made of aluminum die-casting. It is an obvious advantage that the assembling effort is reduced. Disadvantages include high material usage, large construction size, cumbersome tools, and thus high tool costs. In addition, high manufacturing costs due to the necessary cutting of the cylinder running surface are also important. DE 41 02 730 A1 discloses an integral housing for a hydraulic steering wheel of the generic type. This one-piece casing is formed in one piece and is manufactured by an internal high-pressure method. However, in this case, only a branch portion that is simply formed in a region where the pinion and the rack mesh is realized. Depending on the use example, this region needs to be formed structurally complicated. Here the internal high pressure method has its limitations, but at least the manufacturing process
This is done in multiple stages using separate equipment. Such a multi-step manufacturing process is known from Japanese Patent Application Laid-Open No. 63273525. In this known device, the hollow body is provided with an annular groove which enables the internal high pressure method in a working step before the shape molding by the internal high pressure method. This two-stage production process increases the production time of the hollow body thus produced and internally pressure-produced.

──────────────────────────────────────────────────続 き Continuation of front page (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE ), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DK, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IS, JP, KE, KG, KP , KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, US, UZ, VN, YU, ZWF term (reference) 3D033 AA00 GC01

Claims (13)

[Claims] 1. A hydraulic steering system comprising a casing section for accommodating a steering transmission having a pinion and a rack portion, and a casing section following said casing section for arranging a hydraulic steering aid. A method for manufacturing an integrated casing for forming a cold deformable hollow molded body as a starting product, in which one side or both sides are sealed in the vicinity of a region to be deformed by internal high pressure, and an internal high pressure is applied. Thereafter, at least one zone is subjected to a combined internal high-pressure, reverse-drawing method, in which an axially controlled back-feed of the material and, if appropriate, internal high-pressure, straightening, and then internal high-pressure, Straightening and / or drawing and / or stretching untreated areas,
A method for producing an integrated casing for hydraulic steering, characterized in that a local deformation is possibly performed after this main deformation and is terminated by a mechanical finishing. 2. The method of claim 1, wherein the outer diameter of the area not subjected to the internal high pressure is reduced before sealing. 3. An apparatus for carrying out the method according to claim 1, comprising a die, a clamping and feeding unit and a sealing element for closing the hollow body. 1, 2), the end face area of which faces the clamping and feeding unit (9) has a ring joining element divided by radially extending webs (30, 31), the ring joining element of which The gap located between the webs (30, 31) can be closed continuously by a ring (5) with a tongue-like element (6), which is connected to the feed unit (9), (9)
A mandrel (21) arranged axially movable, fixable to a tensioning element or a tensioning and pressing element, insertable into a hollow molding (17) and cooperating with said ring (5), A reverse drawing unit (14) is provided in a region of the die (1, 2) where the internal pressure is applied to the hollow molded body (17), and a ring (5) is provided.
A tongue-like element (6) of the same forms a further ring-joining element, which cooperates with said ring-joining element divided by webs (30, 31). An apparatus for performing the method of claim 1. 4. The device as claimed in claim 3, wherein the ring has an inner contour adapted to the mandrel. 5. The device according to claim 3, wherein the mandrel has a head section and a transition section following or separate from the head section. 6. The device according to claim 3, wherein the reverse-drawing unit has a slidable piston, which is guided in a notch arranged in a die. An apparatus according to any one of the preceding claims. 7. The device according to claim 6, wherein the piston (15) is surrounded by a ring piston (16). 8. A mandrel (21) connected to a feed unit (9) via tensioning or tensioning and pressing means, with or without dependence on said ring (5). 8. The device as claimed in claim 3, wherein the device is axially slidable. 9. The tensioning and pressing means of the ring (5) comprises at least two rods (
9. The device according to claim 8, comprising (7, 8). 10. The device according to claim 8, wherein the tensioning and pressing means of the ring is a tube surrounding the hollow body. 11. The device according to claim 3, wherein the pulling and pressing means of the mandrel (21) is a rod (12). 12. The die according to claim 3, wherein the ring-joining element arranged in the end face region of the die (1,2) is an integrated component of the die (1,2). Item. 13. The die as claimed in claim 3, wherein the ring connecting element is arranged as a separate insert in a cutout arranged in the end face region of the die.
The device according to any one of the preceding claims.