JPH0222386Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to an improvement in rack and pinion steering for vehicles.

(Prior Art) A rack and pinion steering device, which has been widely used as a steering device for vehicles in recent years, has an input shaft that rotates by manual steering and has a pinion, and a rack shaft that meshes with the pinion and moves linearly. Steering is performed by steering the wheels using a link mechanism connected to both ends of the wheel. ) and shocks that return from the wheel side to the input shaft (called shock) are likely to occur, and as a countermeasure to this problem, a piston that is formed by a piston that interlocks with the easy shaft and a fluid cylinder filled with fluid has traditionally been used. A damper device is known in which a damper device having a communication path is installed in the damper device, and vibrations such as the shimmy and backlash are absorbed by the flow resistance of the fluid (Japanese Patent Publication No. 45-9404).

However, due to slight leakage of fluid from the damper device while the vehicle is running, the volume of fluid gradually decreases, so in order to replenish this volume,
A replenishment method has also been proposed in which the chambers on both sides of the piston of a fluid cylinder are refilled by gravity from a container filled with fluid (Japanese Patent Publication No. 49-47390), but since the replenishment pressure tends to be insufficient, replenishment of fluid is not always possible. The problem is that it does not operate smoothly, does not function well due to lack of fluid or compressibility, and is difficult to absorb minute shimmy.

(Problems to be solved by the invention) This invention solves the above-mentioned problems of conventional products, and provides a damper device for rack and pinion steering that reliably replenishes the fluid cylinder and has a simple structure. It is something.

(Means for Solving the Problems) As a means for solving the above-mentioned problems, the configuration of this invention is a rack and pinion type steering system for a vehicle in which wheels are steered by direct motion of a rack shaft. The rack cylinder is divided into two chambers by a piston interlocking with the rack shaft, and a communication passage is provided in the piston to communicate the two chambers, and the two chambers are filled with fluid, and one of the two chambers is filled with fluid. In a rack-pinion steering damper device in which a replenishment means is connected via a replenishment path, the replenishment means includes a replenishment cylinder connected to the replenishment path, and a replenishment cylinder that is disposed within the replenishment cylinder so that the replenishment means is connected to the replenishment path. This damper device for a rack and pinion type steering is characterized by comprising a replenishment piston that urges fluid in a cylinder at a predetermined pressure, and a check valve that prevents backflow of fluid from the chamber.

(Function) The function of the damper device of this invention having the above-mentioned configuration is as follows.

The two cylinders operate in conjunction with the easy shaft, which engages with the pinion that rotates when the input shaft is steered, and moves directly.
A piston having a communication passage that communicates the chambers is subjected to a braking action due to the pressure difference of the fluid in the cylinder when moving through the communication passage of the fluid filling the cylinder. The system is designed to attenuate vibrations and function as a damper device, and in order to replenish the fluid that slightly leaks during running, a replenishment means is provided that replenishes the fluid at a predetermined pressure. The fluid injected into either one of the two chambers of the cylinder is replenished through the communication passage mainly when the piston is not in operation.

(Example) Next, a typical example of the damper device for a rack and pinion type steering according to this invention will be described with reference to FIG.

FIG. 1 is a cross-sectional view of the main parts of an embodiment of the damper device according to this invention, in which reference numeral 1 is a pinion shaft, 2 is a rack shaft, 3 is a piston, 31 is a communication passage, 4 is a cylinder, and 5 is a supply supply. 6 is an elastic member, 7 is a replenishment piston, 8 is a check valve, and 9 is a replenishment path.

When the pinion shaft 1, which is directly connected to the steering wheel, rotates, the rack shaft 2, which engages with the pinion, moves directly to steer the wheels, and the rack shaft 2 has a piston 3 on the same axis. cylinder 4
The piston 3 is provided with a communication passage 31 that communicates the two chambers of the cylinder, and outside the cylinder 4 is a replenishment cylinder 5 as a replenishment means, and inside the replenishment cylinder 5 there is a pressure that is maintained at a predetermined pressure. A replenishment piston 7 movable by the pressure of the set elastic member 6, and a replenishment path connected to one of the two chambers divided by the piston 3 of the cylinder 4 through a check valve 8. 6 is arranged, and both the cylinder 4 and the supply cylinder 5 are completely filled with oil which has a damping effect.

Next, to explain the operation of this embodiment, the rotation of the pinion shaft 1 by steering causes the easy shaft 2 to
is adapted to move directly in both directions to steer the wheels, but an elastic member 6 disposed inside a replenishment cylinder 5 provided outside a cylinder 4 on the same axis as the rack shaft 2 When the chamber 51 is filled with oil while a predetermined set load is applied, the oil is divided by the piston 3 of the cylinder 4 mainly by the pressure of the elastic member 6 when the piston is not in operation.
The pressure also flows into the two chambers 41 and 42, so that the pressure in the chambers 41, 42, and 51 becomes the same.

When the piston 3 moves toward the chamber 41 due to the direct movement of the rack shaft 2 by steering, the oil in the chamber 41 attempts to return to the supply cylinder 51, but since there is a check valve 8 in the supply path 6, the oil does not return to the chamber 51. The liquid cannot return and flows into the chamber 42 through the communication passage 31 of the piston 3. At this time, depending on the speed of the oil flowing through the communication path, the chamber 42 and the chamber 41
Since a pressure difference is generated between the piston 3 and the piston 3 to the opposite side, this force acts as a damping force on the linear motion of the easy shaft 2, absorbing minute shimmy, rattle, etc., and creating a damper effect. It is beginning to appear.

The oil filled in the cylinder 4 leaks out in very small amounts while the vehicle is running, and the oil in the cylinder 4 decreases. Therefore, oil is mainly replenished when the piston is not in operation, and the cylinder 4 is always filled with oil.

(Effect of the invention) As mentioned above, the damper device according to this invention has the following effects:
In a rack and pinion steering system, a fluid cylinder is provided with a piston that interlocks with the rack shaft and is filled with fluid, and a replenishment means that replenishes the fluid at a predetermined pressure is provided, and the replenishment path of the replenishment means is divided by the piston of the cylinder. It is connected to either one of the two chambers, and the piston is connected to one of the two chambers of the cylinder.
Unlike conventional damper devices, we have installed a communication passage that communicates between the chambers, so that the pressure of the replenishment means required to replenish the oil that gradually decreases due to oil leakage during driving can be adjusted to a predetermined predetermined pressure. Since the pressure in the replenishing means is insufficient, conventionally the pressure is absorbed by insufficient oil, compressibility of the oil, elastic deformation of the oil seal, etc. In the damper device of this invention, there is no escape for the oil flow resistance that does not produce a piston damper effect, so even the slightest vibrations such as shimmies and rattles can be sufficiently absorbed to produce a damper effect. .

In addition, since the conventional replenishment pressure, which utilizes the natural fall of the fluid as the pressure of the replenishment means, tends to be insufficient, the fluid replenishment path is provided with a check valve in each of the two chambers divided by the piston of the cylinder. However, according to the damper device according to this invention, it is sufficient to have one fluid supply path, and the structure of the damper device is simplified.

In this embodiment, the set load of the elastic member is used as the predetermined pressure, but the predetermined pressure is not limited to this. Pressure such as hydraulic pressure may also be used, and the rack and pinion type steering is power steering. It's okay.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of an embodiment of a damper device for a rack and pinion type steering according to this invention. In the figure, 1 is a pinion shaft, 2 is a rack shaft, 3 is a piston, 31 is a communication passage, 4 is a cylinder, 5 is a supply cylinder, 6 is an elastic member, 7 is a supply piston, 8 is a check valve, 9 is a supply It is a road.

Claims (1)

[Scope of utility model registration request] A rack and pinion type steering system for a vehicle that steers the wheels by direct motion of a rack shaft, in which the rack cylinder is divided into two chambers by a piston interlocking with the rack shaft, and a communication passage is provided that communicates the two chambers. In the rack and pinion steering damper device, the damper device is provided on the piston, the two chambers are filled with fluid, and a replenishment means is connected to one of the two chambers via a replenishment path, the replenishment means comprising: a replenishment cylinder connected to the replenishment path; a replenishment piston disposed within the replenishment cylinder that urges fluid in the cylinder toward the replenishment path at a predetermined pressure; and a replenishment piston that prevents backflow of fluid from the chamber. A rack and pinion steering device characterized by comprising a check valve.