JPS588468A - Steering power controller of power steering device - Google Patents

Abstract

PURPOSE:To both decrease axial length of a valve and eliminate the necessity for an oil groove introducing reaction force oil pressure, in a power steering device of rotary valve type, by flowing reaction force pressure oil in the interior of a worm shaft and transmitting the reaction force oil pressure to a reaction force generator mechanism. CONSTITUTION:The rear end side of a worm shaft 19 is constructed such that the peripheral surface is combined by a pin to an outer sleeve 23 fitted to a housing 16 while the internal peripheral surface is fitted to the point end part of an input shaft 24. An axially directional hole 34 and a through hole, communicated to said hole 34 and extended at a right angle with the axial direction, are provided in the point end side of the input shafr 24, and one end of a torsion bar 36 is coupled by a pin to the axially directional hole 34. Two steel balls 38 are fitted into the through hole 35 by interposing a coil spring 37. Reaction force pressure oil, flowing from a reaction force oil pressure generator to an oil inlet 22 and filling an internal space 33 of the worm shaft 19 and the through hole 35, flows little except a leak from the periphery of the steel ball 38 to a recirculation oil circuit, and the pressure is changed in accordance with a change of car speed. Accordingly, the steel ball 38 is pressed to a recessed part 40 in the worm shaft 19 by reaction force oil pressure and tension of the spring 37, to generate reaction force corresponding to a car speed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power steering device, and in particular, a spool that is linked to an input shaft, an outer sleeve that is linked to a worm shaft,
The present invention relates to a rotary valve type power steering device that includes a torsion bar that connects an input shaft and a worm shaft.

Conventional power steering devices have the disadvantage that the steering force is too small at high speeds, making the steering unstable.In order to increase the sense of stability at high speeds, various devices have been proposed that change the input/output characteristics depending on the vehicle speed. There is.

Among them, the type that controls the supply flow rate is often used because the control mechanism is simple and the structure of the power steering device body can be used as is with general specifications. However, this type has the disadvantage that even if the flow rate characteristics are varied, the input/output characteristics cannot be changed significantly. Separately, for the type that controls hydraulic reaction force, it is necessary to install a mechanism inside the power steering device that converts the reaction oil pressure into reaction force. There are methods to provide this, but in either case it is necessary to introduce the reaction hydraulic pressure from outside the steering device body, so in addition to adding one oil groove and one seal groove to the outer circumference of the outer sleeve, the piston A space is required to accommodate the pulp, which has the drawback of increasing the axial dimension of the pulp.

The present invention aims to improve the above-mentioned drawbacks of the hydraulic reaction force control type 4a41.

In order to achieve this object, the present invention provides a rotor IJ-pulp type power steering device in which a recess is provided on the inner surface of the worm shaft, a through hole is provided in the input shaft in a direction perpendicular to the axis, and a spring and a pusher are inserted into the through hole. The pusher is fitted into the recessed portion by a spring force, a reaction hydraulic pressure is introduced into the inside of the worm shaft, and the inside of the worm shaft is communicated with the through hole.

To explain this using the example shown in the figure, in Figure 1,
The oil that is sucked up from the tank 1 to the pump 3 via the pipe 2 passes through the pipe 4 and enters the reaction hydraulic pressure generator 5, and is then diverted from the pipe 6 to the pulp housing of the power steering device main body 8. flows inside.

The oil that has entered the power steering device main body 8 returns to the tank 1 through a pipe 9. The signal detected by the vehicle speed sensor 10 attached to the rear part of the vehicle or the axle is rectified.
Sufficient power is required to drive the lenoid 12 in the amplifier circuit 11 . The reaction force hydraulic pressure generator 5 is an lenoid 12.
The hydraulic pressure, which increases as the vehicle speed increases, is transmitted to the interior of the oil inlet provided in the front cover of the power steering device main body 8 via a pipe 7. 1 state, and as the vehicle speed increases, the piston moves in the direction of the arrow, resulting in a state as shown in FIG. 7, in which the oil pressure in the pipe line 7 increases. The structure of the reaction hydraulic pressure generating device 5 is not limited to the above embodiment, and may be of various known structures. Further, the pipe line 6 connecting the reaction force hydraulic pressure generating device 5 and the power steering device main body 8 may be directly connected to the pipe line 4 from the pump 3. Power steering device main body 8
As shown in FIGS. 2 to 5, the front cover 15 is screwed and fixed to the front side of the gear case 14, and the valve housing 16 is fitted and fixed to the rear side. Further, a piston 17 is oil-tightly fitted into the gear case 14, and the gear case 14 is divided into two cylinder chambers. A rack is provided on the lower surface of the piston 17 and meshes with a sector gear of the output shaft 18. The output shaft 18 is supported by the gear case 14 in a direction directly opposite to the piston 17, and rotates as the piston 17 moves in the axial direction. A ball screw groove is provided on the inner peripheral surface of the piston 17, and the worm @ 19 and the piston 17 are connected to each other via balls that fit into the ball screw groove and roll.
are mated with each other. The tip of the worm shaft 19 is connected to the front cover 15
It is supported in the axial direction by a thrust needle roller bearing. A sealing member 21 is provided between the outer peripheral surface of the tip of the worm shaft 19 and the cylindrical inner surface of the front lid 15 fitted thereto.
is provided, and a front cover 15 is provided opposite to the end surface of the worm shaft 19.
A second oil inlet 22 connected to the conduit 7 is provided at. The rear end of the worm shaft 190 has a flange-like connection part, which is pin-coupled to the outer sleeve fitted to the pulp housing 16 on the outer circumferential surface, and fitted to that tip of the input shaft on the inner circumferential surface. . The outer sleeve is supported in the axial direction by a thrust ball bearing 5 in the pulp housing 16, and is fitted with the spool holder on the inner circumferential surface. The spool 26 is externally fitted onto the input shaft with a gap and is connected with a pin, and the gap forms part of the oil return circuit. The valve housing 16 supports the input shaft row with a needle roller bearing n, and the outside thereof is sealed with an oil seal.
It is equipped with an oil outlet (capital) connected to. The space 31 of the valve housing accommodating the thrust ball bearing δ communicates with a gap in the inner circumferential surface of the spool joint. On the tip side of the input shaft, there is provided an axial hole and a through hole extending perpendicular to the axis and communicating with the axial hole. One head of a torsion bar bracket is fitted into the axial hole and connected with a pin, and two steel balls can enter and exit the through hole with the coil spring 37 in between. They are mated. A 7-shaped groove-shaped recess 39 provided on the inner peripheral surface of the flange-like connection part of the steel ball worm shaft 19
The coil spring 37 presses the coil spring 37 against the coil spring 37. The steel ball does not necessarily have to be a steel ball, and may be a plunger having a spherical head. A sealing member 32 is provided on the fitting surface between the tip of the input shaft and the worm shaft 19, and a part of the sealing member 32 is provided to seal the space 33 between the inner circumferential surface of the worm shaft 19 and the outer circumferential surface of the torsion bar and the spool force. It is cut off from the oil return circuit on the inner peripheral surface.

As mentioned above, one head of the torsion bar fits into the hole in the axial direction of the input shaft, but the other head also fits into the shaft hole at the tip of the worm shaft 19 and is connected with a pin. A concave groove 40 extending over the entire length in the axial direction is provided on the outer surface of both viewing parts, and communicates with the through hole 35 of the input shaft, the space, and the second oil inlet n. The main flow of the pressure oil flowing through the pipe line 6 enters the inside of the outer sleeve field from the first oil inlet 29 of the pulp housing through the outer sleeve periphery 41 and the introduction oil hole 42 shown in FIG. The flow is diverted from the oil filler 43, 44 through the space 31 in which the thrust ball bearing 5 is housed through the gap between the cylinders on both sides of the piston 170, and returns to the tank 1 from the oil outlet. Reaction hydraulic pressure generator: The reaction hydraulic pressure that flows from 5 to the second oil inlet ρ through the pipe 7 and fills the internal space of the worm shaft and the through hole is returned from the periphery between the steel balls. There is almost no flow other than leakage into the oil circuit, and the pressure increases and decreases as the vehicle speed increases.Accordingly, the bulb is pressed against the four parts 4o on the inner surface of the worm shaft by the reaction oil pressure and the spring force of the coil spring 37, and as the vehicle speed increases. A corresponding reaction force is generated.The spring force of the coil spring 37 may be set to such an extent that the steel ball does not separate from the recess 40, and the reaction force may be generated entirely by hydraulic pressure. However, a certain amount of reaction force may be generated.

The oil groove for introducing reaction hydraulic pressure into the tarsleeve of the power steering device of the present invention configured as described above, and the oil groove for introducing the reaction oil pressure in the axial direction.
There is no need to provide one seal groove for each block, and
Since the reaction force generating mechanism is not provided inside the valve, there is an effect that the axial length of the valve can be shortened. In addition, since reaction hydraulic pressure is not introduced to the pulp, the current non-speed-sensitive power steering device can be left as it is, and the reaction force can be controlled using external hydraulic pressure using the IAUD. This also has the effect of easily adding a set load due to coil splashing.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a circuit diagram, Fig. 2 is a vertical sectional view of the power steering device main body, and Fig. 3 is a cross-sectional view of the main body of the power steering device.
Figure 4 is a cross-sectional view along line N-'IV in Figure 2, Figure 5 is 1 = tank, 3: pump, 5: reaction hydraulic pressure generator, 8: power rudder. The main body of the collecting device, lO
:Vehicle speed sensor, 11: Rectifying wave amplifier circuit, 12; Renoid, 14: Gutter, 24=Input shaft, 26: Spool,
31: Space, 32: Seal member, 33: Space, 35 = Through hole, 36: Torsion bar, 37: Coil spring, 38
= steel ball, 39: concave portion, 40: concave groove. Hook applicant: NSK Ltd. / f / η り凋, f 2 fI! J! 4 Figure ft bubbles

Claims (1)

[Claims] (1) In a rotary valve type power steering device comprising a spool that carries stray electricity to the input shaft, an outer sleeve that interlocks with the worm shaft, and a torsion bar that connects the input shaft and the worm shaft, the inner surface of the worm shaft A recess is provided in the input shaft, a through hole is provided in the direction perpendicular to the axis, a spring and a presser are fitted into the through hole, the presser is pressed against the recess by the spring force, and a reaction force is generated inside the worm shaft. A steering force control device for a power steering device, characterized in that a hydraulic pressure is introduced and the inside of a worm shaft communicates with the through hole.