JP3585325B2 - Manufacturing method of power steering housing - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a power steering housing of a power steering device. More specifically, the present invention relates to a method for manufacturing a power steering housing in which a hydraulic oil supply / discharge passage from a control valve to a power cylinder is integrally formed with a housing including the control valve and the power cylinder.
[0002]
[Prior art]
A method of manufacturing a power steering housing of this type has been performed, for example, as follows.
[0003]
That is, in the manufacturing method, a housing 22 composed of a control valve 20 and a power cylinder 21 as shown in FIG. 8 is formed by casting, and then a hydraulic oil for connecting the control valve 20 and each cylinder chamber of the power cylinder 21 The supply / discharge pipes 23 a and 23 b are provided outside the housing 22.
[0004]
However, in the power steering housing, since the hydraulic oil supply / discharge pipes 23a, 23b are piped outside the housing 22, the mountability on a vehicle is poor, and the hydraulic oil supply / discharge pipes 23a, 23b are not provided. Are easily damaged by stepping stones and the like.
[0005]
In addition, since the respective hydraulic oil supply / discharge pipes 23a and 23b are attached to the housing 22, related parts are required, and an assembling operation must be performed. Therefore, productivity was low and cost was high.
[0006]
In order to solve such a problem, as disclosed in Japanese Utility Model Laid-Open Publication No. 55-104577, Japanese Patent Laid-Open No. 7-257408 and Japanese Patent Laid-Open No. 7-257409, a housing for power steering is cast and a control valve and a power valve are mounted. There has been proposed a manufacturing method in which a hydraulic oil supply / discharge passage from a control valve to a power cylinder is integrally formed with a cylinder housing.
[0007]
[Problems to be solved by the invention]
However, in any of the manufacturing methods, it is difficult to easily form the power steering housing having a complicated shape, and in particular, the power steering housing provided with a complicated hydraulic oil supply / discharge passage is simply manufactured. It was difficult to mold.
[0008]
The present invention has been made in view of the above, and an object of the present invention is to provide a method for manufacturing a power steering housing that easily manufactures a power steering housing having a complicated shape.
[0009]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a method for manufacturing a power steering housing, wherein a hydraulic oil supply / discharge passage from a control valve to a power cylinder is integrally formed in a housing including a control valve and a power cylinder by casting. A plurality of cores are arranged and cast in portions of the hydraulic oil supply / discharge passage corresponding to molding.
[0010]
The invention according to claim 2 is characterized in that after the casting, a predetermined process is performed on the cast housing.
[0011]
According to the first aspect of the present invention, there is provided a method for manufacturing a power steering housing in which a hydraulic oil supply / discharge passage from a control valve to a power cylinder is integrally formed with a housing including a control valve and a power cylinder by casting. Since a plurality of cores are arranged and cast in the relevant portion of the discharge path, the hydraulic oil supply / discharge path core is composed of a plurality of cores, and each core is removed after casting (after casting). In this case, the core can be easily taken out, and even if the power steering housing, particularly the hydraulic oil supply / discharge passage provided in the housing, has a complicated shape, the core can be easily manufactured.
[0012]
According to the second aspect of the present invention, after the casting, the cast housing is subjected to a predetermined processing. For example, the control valve and each hydraulic oil supply / discharge path, or each hydraulic oil supply / discharge path and each power cylinder If a simple drilling process is performed to connect the portion to be the cylinder chamber, the hole functions as a hydraulic oil supply / discharge path, and a power steering housing can be easily formed.
[0013]
【Example】
1 to 4 show one embodiment of a method for manufacturing a power steering housing according to the present invention, and each figure is a partial cross-sectional side view of each step.
[0014]
First, although not shown, a mold having a space for forming a housing composed of a control valve and a power cylinder is formed, and a control valve side hydraulic oil supply / discharge path forming core and a power cylinder are formed in a corresponding portion of the hydraulic oil supply / discharge path. A core (for example, a core of casting sand) is provided for the side working oil supply / discharge path forming core.
[0015]
In this state, a casting metal, for example, an aluminum alloy for casting, is cast into the mold by gravity or the like to form a housing 3 comprising a control valve 1 and a power cylinder 2 as shown in FIG. And a projection 3a provided on a bent portion of the housing 3 made of the metal. Due to this molding, the protruding portion 3a is provided with a forming portion of the hydraulic oil supply / discharge passage 4 extending from the control valve 1 to the power cylinder 2, and a control valve side hydraulic oil supply / discharge passage forming core 5a and a power cylinder side actuation. A core 5 is provided which is divided into an oil supply / discharge passage forming core 5b, and a control valve 1 and respective hydraulic oil supply / discharge passages 4 and respective hydraulic oil supply / discharge passages 4 are provided at the ends of the projections 3a. Concave cuts 6 are provided respectively for facilitating the drilling work of holes connecting the power cylinders 2 to portions that become cylinder chambers. In the drawings, the molding sand of the control valve 1, the power cylinder 2 and the concave cut 6 is removed.
[0016]
Next, the control valve side hydraulic oil supply / discharge path forming core 5a and the power cylinder side hydraulic oil supply / discharge path forming core 5b are pulled out in the directions of arrows C and D, respectively, to reach the control valve 1 to the power cylinder 2. As shown in FIGS. 5 and 6, the hydraulic oil supply / discharge passage 4 is formed on a protrusion 3a provided at a bent portion of the housing 3. As shown in FIG.
[0017]
Thereafter, as shown in FIG. 2, a hole is formed in the concave cut 6 so that the control valve 1, each hydraulic oil supply / discharge path 4, each hydraulic oil supply / discharge path 4 and each cylinder chamber of the power cylinder 2 are formed. Each hole 7 connecting between the holes is formed.
[0018]
Thereafter, as shown in FIG. 3, the opening of each cut 6 having a hole 7 is covered with a metal film 8 by welding to manufacture a power steering housing.
[0019]
After manufacturing, a power steering device is manufactured by inserting a valve into the control valve 1 and inserting a rack shaft 10 provided with a piston 9 into the power cylinder 2 as shown in FIG.
[0020]
The method of manufacturing the power steering housing includes a control valve-side hydraulic oil supply / discharge path forming core 5a and a power cylinder-side hydraulic oil supply / discharge path forming core 5b in a portion corresponding to the formation of the hydraulic oil supply / discharge path 4. In order to arrange and cast a plurality of cores 5, after casting (after casting), if each of 5 a and 5 b is pulled out from another direction (left-right direction), a protrusion 3 a provided on a bent portion of housing 3 is provided. Core 5 can be easily taken out.
[0021]
Therefore, even a power steering housing having a complicated hydraulic oil supply / discharge passage 4 can be easily manufactured.
[0022]
Further, after casting, predetermined processing is performed on the cast power steering housing, for example, the control valve 1 and each hydraulic oil supply / discharge passage 4, and each hydraulic oil supply / discharge passage 4 and a portion that becomes each cylinder chamber of the power cylinder 2. When the opening of the cut 6 in which the hole 7 is formed is covered with a metal film 8, the hydraulic oil supply / discharge path 4 functions as a supply / discharge path for the hydraulic oil, and the power The steering housing can be easily formed.
[0023]
In the above embodiment, the plurality of cores 5 composed of the control valve-side hydraulic oil supply / discharge path forming core 5a and the power cylinder-side hydraulic oil supply / discharge path forming core 5b are provided by the control valve 1 and the power cylinder 2. The two are separated at the bent portion of the boundary, but any other position may be used as long as the core can be easily removed. For example, the intermediate position may be an intermediate position of the combined length of the two cores 5a and 5b.
[0024]
FIG. 7 is an example of another manufacturing method of the power steering housing.
[0025]
In this manufacturing method, a pipe 12 filled with molding sand 11 is arranged and cast in a portion corresponding to the forming of a hydraulic oil supply / discharge passage, and after casting, a tip 13 a of the pipe 12 protruding into the control valve 1 and the power cylinder 2. , 13b and the casting sand 11 in the pipe 12 is taken out to form the hydraulic oil supply / discharge passage 14.
[0026]
According to such a manufacturing method, the molding sand 11 filled in the pipe 12 can be easily taken out, and the housing for power steering in which the hydraulic oil supply / discharge passage 14 is integrally provided in the housing 15 can be easily manufactured. Will be possible.
[0027]
【The invention's effect】
As described above, according to the present invention, a power steering housing having a complicated shape, in particular, a power steering housing provided with a complicated hydraulic oil supply / discharge path, can easily take out a hydraulic oil supply / discharge path forming core. Thus, it can be easily manufactured.
[Brief description of the drawings]
FIG. 1 is a partially sectional side view showing a state after casting of an embodiment of a method for manufacturing a power steering housing according to the present invention.
FIG. 2 is a partial cross-sectional side view showing a state in which predetermined processing has been performed in an embodiment of the method of manufacturing the power steering housing according to the present invention.
FIG. 3 is a partial cross-sectional side view showing a state in which a notch opening provided at an end of a hydraulic oil supply / discharge passage is covered with a metal film in one embodiment of a method of manufacturing a power steering housing according to the present invention. It is.
FIG. 4 is a partial cross-sectional side view showing a state in which a rack shaft provided with a piston is incorporated in a power cylinder of one embodiment of a method for manufacturing a power steering housing according to the present invention.
FIG. 5 is an enlarged perspective view of a main part of a power steering housing molded by the manufacturing method of the present invention.
FIG. 6 is a sectional view taken along line AA of FIG.
FIG. 7 is a sectional view of a power steering housing after casting in another example of a method of manufacturing the power steering housing.
FIG. 8 is a perspective view of a general power steering housing.
[Explanation of symbols]
1: Control valve, 2: Power cylinder, 3: Housing, 4: Hydraulic oil supply / discharge path, 5: Core, 5a: Control valve side hydraulic oil supply / discharge path forming core, 5b: Power cylinder side hydraulic oil supply Extrusion core, 6: notch, 7: hole, 8: metal film.

Claims (2)

In a manufacturing method of a power steering housing, a hydraulic oil supply / drain passage from a control valve to a power cylinder is integrally formed by casting into a housing including a control valve and a power cylinder.
The hydraulic oil supply / discharge path includes a control valve side hydraulic oil supply / discharge path protruding from the control valve, and a power cylinder side hydraulic oil supply / discharge path protruding from the power cylinder,
A bent portion is provided at a boundary between the control valve side hydraulic oil supply / discharge path and the power cylinder side hydraulic oil supply / discharge path,
The method for manufacturing a power steering housing, wherein the control valve-side hydraulic oil supply / discharge path and the power cylinder-side hydraulic oil supply / discharge path are cast by arranging separate cores . In the casting, a concave notch is formed near the end of the control valve side hydraulic oil supply / discharge passage and near the end of the power cylinder side hydraulic oil supply / discharge passage, and the concave cut is covered with a metal film. 2. The method for manufacturing a power steering housing according to claim 1, wherein an end of the control valve-side hydraulic oil supply / discharge passage and an end of the power cylinder-side hydraulic oil supply / discharge passage are formed.

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