JPH0130295Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a pressure oil rotary valve device for a rack-and-pinion type power steering device, and its purpose is to allow pressure oil from the import of the valve housing to flow into the annular oil groove of the valve body. This is intended to prevent the generation of beeping noises due to turbulence in the pressure oil.

Figures 1 and 2 show the import 1 of the valve housing 1 of the pressure oil rotary valve device of a conventional rack-and-pinion power steering device.
Pressure oil from a flows into the annular oil groove 2a on the outer periphery of the valve body 2 fitted into the inner hole 1b of the valve housing 1, and further flows into four oil passages 2b provided in the radial direction from the annular oil groove 2a. The oil flows into the return port 1c from the oil passage 3b through a plurality of axial oil passages 3a formed on the outer periphery of the valve spool portion 3 fitted into the inner hole 2c of the valve body 2, which rotates by operating the handle, and flows into the cylinder (not shown). ), and when the handle shaft is rotated significantly, the rack 5, which meshes and slides with the pinion 4, is pressurized by the oil pressure of the cylinder, making the handle operation easier.
The import 1a of the valve housing 1 and the annular oil groove 2a on the outer periphery of the valve body 2 are communicated with each other through a through hole 1d having a circular cross-section. Since the through hole 1d cannot be made larger than the predetermined diameter, the flow velocity of the pressure oil flowing through the through hole 1d becomes 8 m/sec or more, and when the pressure oil flows into the annular oil groove 2a, the flow is disturbed. A beeping sound is generated. This beeping sound occurs not only during valve operation but also in the neutral position, and in particular, the beeping sound is highest at a position where the oil passage 2b is rotated approximately 10 degrees from the position where the through hole 1d meets the oil passage 2b. In order to reduce this beeping sound, the through hole 1d can be made larger to reduce the flow velocity of the pressure oil, or the annular oil groove 2a can be made deeper. This goes against the trend of smaller and lighter parts, which goes against the requirement that parts become smaller, and with the shift to front-wheel drive, smaller and lighter steering devices, the steering system moves closer to the passenger compartment and this beeping sound is transmitted into the passenger compartment through the steering wheel column, making it difficult for the driver to drive. It had the disadvantage of causing discomfort.

The present invention communicates the import tip of the valve housing with the annular oil groove of the valve body through an elongated concave notch along the annular oil groove, thereby reducing the flow velocity of the pressure oil coming out from the import tip and transferring the pressure oil into the annular oil groove. The beep sound is made smaller by shifting in the tangential direction of

3 and 4 show an embodiment of the present invention, in which the tip of the import 11a of the valve housing 11 is a through hole 11a' having a circular cross section. This through hole 11a' and the annular oil groove 12a on the outer periphery of the valve body 12 are connected to an elongated half-moon-shaped recessed part 12 along the annular oil groove 12a.
a′ is connected.

Note that the recessed notch 12a' may have another shape as long as it is elongated.

According to the present invention, even though a large number of packings are provided on the outer periphery of the valve housing, an elongated concave notch is formed between the packings along the annular oil groove, so that oil can be removed from the through hole with a circular cross section at the import tip. The flow velocity of the pressurized oil is reduced to 3m/
sec or less, and since the pressure oil from the recessed part can be transferred in the tangential direction of the annular oil groove, direct impact on the radial oil passage formed in the annular oil groove can be minimized, and beeping noise can be minimized. It can be reduced by about 25-30dB. The recessed part can be formed from the inner hole side of the valve housing using a slot tool or the like having approximately the same width as the annular oil groove, and since the import part has a circular cross section, it can be formed with a drill, making machining easy.

[Brief explanation of the drawing]

Fig. 1 is a front sectional view of the conventional device, Fig. 2 is a plane sectional view taken along the line A-A in Fig. 1, Fig. 3 is a plane sectional view equivalent to Fig. 2 of an embodiment of the present invention, and Fig. 4 is a plane sectional view taken along line A-A in Fig. 1. It is a BB side view of FIG. 11...Housing, 11a...Import, 11
a'...Through hole, 12...Valve body, 12a...Annular oil groove, 12a'...Concave cutout.

Claims (1)

[Scope of utility model registration request] Pressure oil from the import of the valve housing flows into the annular oil groove on the outer periphery of the valve body fitted into the inner hole of the valve housing, and the pressure oil is released by relative displacement with the valve spool fitted into the inner hole of the valve body, which rotates when the handle is operated. The rack and pinion is characterized in that the import tip of the valve housing and the annular oil groove of the valve body communicate with each other through an elongated recess along the annular oil groove. Pressure oil rotary valve device for type power steering device.