KR20020007732A - Teeth root structure of piston rack for power steering - Google Patents

Abstract

PURPOSE: Structure of the addendum of a piston rack tooth is provided to compensate strength when a sector gear is rotated leftward and rightward, to increase a gear engagement ratio of a piston rack and the sector gear, and to keep the balanced strength of the piston rack. CONSTITUTION: Round portions(20a) at the addendum of a piston rack and inner round portions(20b) have a specific diameter. According to the relatively large diameter of the round portions, the fatigue rupture is minimized when the sector gear engaged with the piston rack is rotated. By uniformly distributing the force to the gears of the piston rack, strength is compensated. Therefore, the life span of a piston rack is lengthened. Moreover, the clearance of a steering wheel is minimized.

Description

Root Structure of Power Steering Piston Rack {TEETH ROOT STRUCTURE OF PISTON RACK FOR POWER STEERING}

The present invention relates to a root structure of a piston rack of a power steering device which is inserted into a cylinder of an automobile steering body and is formed on a piston that is slid left and right by hydraulic pressure and rotates a sector gear engaged by a reciprocating motion of a piston. By forming a plurality of round parts formed on both sides of the piston rack root and the inner side of the rounded tooth with a predetermined diameter of the same size, the coupling ratio between the piston rack and the sector gear is improved, so that both round parts and the inner round part are steered when steering the steering wheel. It is related to the root structure of a power steering piston rack by allowing the same force to be applied, thereby allowing the applied force to be dispersed to reduce the fatigue failure of the piston rack.

In general, a motor vehicle uses a power steering device 1 for light and fast steering, and hydraulic pressure generated by driving an oil pump (not shown) is applied to the valve flow path 3 of the sleeve 2 by the mutual displacement difference of the valves. The piston rack flows from the inside to the outside and passes through an internal flow path (not shown) of the steering body 4, and the piston 5 reciprocates inside the cylinder 6 of the steering body 4, thereby releasing the piston rack. (7) is transferred to the left and right, the sector gear (8) engaged with the piston rack (7) in accordance with the movement direction of the piston (5) is to rotate left and right to smooth the operating force of the steering wheel. .

Referring to Figure 3 the root structure of the conventional piston rack as follows.

First, the tooth root portion 10a of both gears formed at the outermost side of the plurality of tooth roots (roots) 10 formed in the conventional piston rack 7 is a plurality of gear root rounds formed inside. The size (diameter or radius) is formed relatively larger than the portion 10b.

On the other hand, when the vehicle is traveling at a high speed, the steering wheel is lightly steered, so that excessive force is not applied to the root 10a. However, when the steering wheel is excessively operated during low-speed driving or parking of the vehicle, the piston rack 7 and the sector gear Excessive force is applied to (8).

As described above, when the piston rack 7 excessively rotates the sector gear 8, the force acts the most on the root round portion 10a of the gear located at the outermost side of the piston rack 7, but the both roots The size (diameter or radius) of the round portion 10a is larger than the size (diameter or radius) of the inner root root portion 10b (that is, the cutting amount of the outer round portion 10a is the inner round portion 10b). Less than the amount of cutting), the strength can be compensated, so that the fatigue fracture can be reduced.

However, as described above, if the sizes of the outermost root portion 10a and the inner root portion 10b are different from each other, the strength of both root root portions 10a is controlled by steering wheel steering. Although it may be compensated for, the gears formed at both ends of the sector gear 8 are in direct contact with only the root portion 10a of both sides of the piston rack 7, thereby lowering the coupling ratio.

Therefore, long-term use decreases the engagement ratio between the sector gear 8 and the piston rack 7, resulting in play in the steering handle. Accordingly, the sector gear 8 may be readjusted, as described above. According to an unbalanced engagement rate, there is a problem that an adverse effect of increasing fatigue failure of the inner gears of the piston rack 7 occurs.

The present invention devised to solve the above problems is that the round parts of both gear roots are meshed with the sector gear so that the strength can be compensated even when the sector gear is rotated left and right, and the ratio of the piston rack and the sector gear is increased. And the piston rack maintains an overall balanced strength.

The above object is, according to the present invention, a piston rack of a power steering device which is inserted into a cylinder of an automobile steering body and is formed in a piston which is slid left and right by hydraulic pressure to rotate left and right sector gears engaged by reciprocating pistons. In the root structure of the, it is achieved by forming both round parts and the plurality of round parts formed on the inside of the piston rack tooth root to a predetermined diameter of the same size.

1 is a partially cutaway perspective view showing the structure of a conventional power steering device;

Figure 2 is a cross-sectional view showing the structure of a conventional power steering device.

Figure 3 is a cross-sectional view of the piston showing the root structure of a conventional power steering device.

Figure 4 is a cross-sectional view of the piston showing the root structure of the power steering apparatus of the present invention.

Explanation of Drawings

1-Power Steering 2-Sleeve 3-Valve Euro

4-steering body 5-piston 6-cylinder

7-piston rack 8-sector gear

Root (root) of 10-conventional piston rack

20-root of the present invention piston rack (root)

Hereinafter, the configuration of the present invention will be described in FIG.

Power that is inserted into the cylinder 6 of the automobile steering body 4 and formed on the piston 5 which slides left and right by hydraulic pressure to rotate the sector gear 8 engaged by the reciprocating motion of the piston 5 left and right. In the root structure of the steering gear piston rack, both round portions 20a of the root of the piston rack 7 and a plurality of round portions 20b formed inside are formed to have a predetermined diameter of the same size.

The technique of the present invention having the above-described configuration will be described in FIG.

First, the piston rack (7) by forming a relatively large size (diameter or radius) of the round portion 20 as shown in Figure 4 during machining of the root of the piston rack (7), so that the piston rack (7) and the sector gear (8) Minimizes fatigue failure when engaged and rotates the sector gear 8.

When the size of the root round portion 20 is formed to have the same predetermined diameter as described above, in order to process only the both round portions 20a of the piston rack 7 when the piston rack 7 is processed, the cross section of the grinding wheel The inconvenience of having to manufacture a predetermined shape or to process the root round portion 20a of the piston rack 7 separately, as well as the ratio of engagement with the sector gear 8 is increased, so that the gears of each of the piston rack 7 The uniform force acts on the wheels, thereby dividing the force concentrated only on both gears of the piston rack 7.

As described above, the present invention forms the root round portion of the piston rack as a whole so that the excessive force received from the sector gear can be evenly divided between the gears of the piston rack, so that the force acting only on both gears of the piston rack is concentrated. The force can be distributed to each gear of the piston rack to compensate for the strength, thereby extending the life of the product and minimizing the play of the steering handle caused by the decrease in the engagement rate during use. It is a very useful invention having an effect.

Claims (1)

In the root structure of the piston rack of the power steering device is formed in the piston which is inserted into the cylinder of the steering wheel of the vehicle and is slid left and right by hydraulic pressure to rotate the sector gear engaged by the reciprocating motion of the piston, Root structure of the piston rack of the power steering apparatus, characterized in that for forming a plurality of round portions formed on both sides of the piston rack root root and the inside of a plurality of round diameters of the same size.