JPS5820824B2 - Steering force control device for power steering device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steering force control device for a power steering device, and more particularly to a novel steering force control device that changes the steering force according to the magnitude of the carrying load of a vehicle. .

A power steering system (hereinafter abbreviated as P-S) provides an auxiliary force to the steering force of the steering wheel and enables light steering operation. The linkage type is known.

The linkage type is further classified into a combined type in which the power cylinder and control valve are integrated, and a separate type in which these two elements are provided separately.

By the way, these conventional P and S vehicles, regardless of their type, always have a reaction force mechanism that transmits a reaction force corresponding to the steering output to the steering wheel in order to make the driver sense steering resistance. P and S can be classified as follows depending on how the reaction force to the steering wheel is generated.

The first is a type that determines the magnitude of the reaction force of the steering wheel according to the magnitude of the pressure in the working chamber that generates the steering output at P and S, that is, the magnitude of the auxiliary force ratio of the steering force. P
, S is a type in which a reaction force chamber for applying steering resistance to the steering wheel is provided separately from the working chamber of the steering wheel, and the reaction force of the steering wheel is determined depending on the magnitude of the pressure in the reaction force chamber.

The third type combines both the first and second types described above, and applies a reaction force to the steering wheel depending on the magnitude of the auxiliary force ratio and the magnitude of the reaction force of the reaction force chamber, In all of the above three types, the greater the operating pressure caused by P and S, the greater the steering resistance of the steering wheel.

Recently, in order to ensure running stability at high speeds, various pressure regulation or flow rate control means have been developed to ensure that the reaction force applied to the steering wheel increases at high speeds even with the same steering output ratio (auxiliary force ratio). However, the direction of improvement of these P and S is to detect the speed of the vehicle and control the reaction force applied to the steering wheel according to this vehicle. factors are completely left out of consideration.

In order to obtain more ideal drivability of vehicles equipped with P and S, especially ideal drivability of trucks whose payload changes greatly between empty and loaded, the inventors of the present invention have developed the following The concept of vehicle speed bias has been revised, and new focus has been placed on controlling the steering outputs of P and S depending on the magnitude of the live load.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a steering force control device that allows the steering force of the steering wheel to be relatively small when the vehicle's carrying load is small.

Further, the purpose of the pond of the present invention is to control the fluid pressure, which is the source of operating pressure for P and S, as well as the source of the reaction force applied to the steering wheel, in accordance with the magnitude of the live load.

Furthermore, to describe the purpose of the present invention for each type, P and S, in the type equipped with a reaction force chamber that applies a reaction force to the steering wheel, the pressure in the reaction force chamber is reduced as the live load increases. In the P and S models, which have only the working chamber, the pressure of the fluid guided to the working chamber is set to be small, and the pressure in the compartments of the working chamber and the reaction force chamber is set to be small. In the PS used to apply a reaction force to the steering wheel, the higher the live load, the higher the pressure in the working chamber and the lower the pressure in the reaction force chamber, increasing the ratio of auxiliary force to the steering force. The purpose is to reduce the operating resistance of the handle.

Another object of the present invention is to avoid producing more PS output than necessary in relation to the live load, to reduce horsepower consumption, and to prevent excessive stress and hydraulic pressure from occurring in the PS system. In addition to improving the wear rate of each sliding part and gear part and the durability of seals, we also tried to prevent the shock and vibration of kick packs etc. from being excessively suppressed by the handle and to improve the link mechanism. It is something to do.

In order to achieve the above object, the present invention attempts to change the pressure of the fluid introduced from the oil pump into the working chamber, the reaction chamber, or both the working chamber and the reaction chamber of the PS depending on the magnitude of the live load. The vehicle is equipped with a load detector that generates an output according to the load of the vehicle, and a fluid pressure control means that responds to the output of the load detector, and the pressure of the fluid is controlled by the fluid pressure control means. , the larger the load becomes, the greater the ratio of auxiliary force to the steering force of the steering wheel is.
In other words, the operating resistance of the steering wheel is reduced.

The invention will now be described in detail with reference to illustrated embodiments.

FIG. 1 shows a first embodiment of the present invention, in which pressure oil from an oil pump 1 driven by a vehicle engine reaches P and S4 via a pipe 2a1, a pressure control valve 3, and a pipe 2b. , and returns to the oil pump 1 via the pipe 5.

This P, 84 is of a type that has a reaction force chamber that applies a reaction force to the steering wheel in the working chamber pond that generates the steering output, and the pipe 2b is connected to this working chamber, but the pressure A conduit 6 from the control valve 3 is connected to the reaction chamber.

The pressure control valve 3 is provided with a chamber 8 through which the conduit 2a16 communicates and a chamber 9 through which the conduit 2b communicates in the housing 7, and the communication area of the communication hole 10 that communicates between the two chambers 8 and 9 is set as a poppet. By changing the position of the valve 11, the line 2b
The poppet valve 11 is configured to control the fluid pressure in the pipe line 6, that is, the fluid pressure reaching the working chambers and reaction chambers of P and S4. Its position is determined.

Note that 13 indicates an orifice that medically confirms the supply of pressure oil from the oil pump 1 to the PS 4 even when the poppet valve 11 closes the communication hole 10.

The load detector 12 is connected to the chassis frame 14 and axle 1 of the vehicle.
5 or an integral member thereof, and
The system detects the live load based on a change in the distance between the frame 14 and the axle 15, and generates an output corresponding to this.The output is input to the solenoid 18 via the filter 16 and controller 17. As the load increases, the poppet valve 11 is sucked and moved in the direction of the arrow in the figure to increase the communication area of the communication hole 10.

Note that the filter 16 removes high frequency components generated in the load detector 12 when the vehicle curves or runs on a rough road, and
This is to prevent the vibration phenomenon of 1 itself.

In this device having the above configuration, the poppet valve 11 changes its position and changes the communication area of the communication hole 10 depending on the size of the vehicle's carrying load. , the position of the poppet valve 11, the diameter of the communication hole 10, and other factors are determined.

That is, when the load is empty, the poppet valve 11 is used. Communication hole 1
The communication area between chambers 8 and 9 becomes the smallest, and the flow path area between chambers 8 and 9 becomes the most constricted.
The oil pressure in the conduit 6 leading to the reaction chambers P and S4 has increased, so when the steering wheel is operated with no cargo loaded, the pressure in the chamber 8 and the steering resistance increase the pressure P, As a result of the pressure in the working chamber of S4 acting as a reaction force against the steering wheel, the reaction force acting on the steering wheel when unloaded is the largest among the P and S systems.

In the present invention, in consideration of this situation, various elements are determined in advance so that an appropriate steering force can be obtained when the vehicle is empty.

Next, at the time of loading, the load detector 12 generates an output according to the magnitude of the loaded load, and this output suction-moves the poppet valve 11 downward in the figure via the controller 17 and the solenoid 18.

For this reason, the communication area of the communication hole 10 becomes smaller than when the load is empty, and as a result, the restricting effect on the flow path between the chambers 8 and 9 is reduced, and the pressure on the side of the chamber 8 becomes lower than when the load is empty. On the other hand, the pressure on the side of the chamber 9 becomes higher than when it is empty.

Therefore, the oil pressure in the pipe 2b leading to the working chambers of P and S4 increases, and the oil pressure in the pipe 6 communicating with the reaction force chamber that applies a reaction force to the steering wheel decreases. While the steering output is reduced, the operating resistance of the steering wheel is reduced.

In other words, when the vehicle is loaded, the steering outputs of P and S4 are adjusted according to the magnitude of the loaded load, so it is possible to operate the steering wheel at the same level or lighter than when the vehicle is unladen.

The embodiments shown in FIGS. 2, 3, and 4 show devices in which the load detector is different from that in FIG. The configuration of
The device is the same as that shown in FIG.

Therefore, in FIGS. 2 to 4, the same components as in FIG. 1 are given the same reference numerals.

In the embodiment shown in FIGS. 2 and 3, one end of a leaf spring 21 is pivotally connected to the upper end of a connecting rod 20 installed upright on an axle 15 of the vehicle, and the leaf spring 21 itself is attached to the chassis frame 14 with a pin 22. The other end of the leaf spring 21 is pivotally connected to the poppet valve 11 of the pressure control valve 3, and when the chassis frame 14 and the axle 15 are close together, the leaf spring 21 and the poppet valve 11 are displacement in the direction of the arrow.

In the embodiment of FIG. 4, an air spring 23 is installed between the chassis frame 14 and the axle 15, and the pressure in the air spring 23 is guided into a chamber 24 formed in the housing 7 of the pressure control valve 3.
The poppet valve 11 is configured to be displaced in the direction of the arrow as the pressure increases, that is, as the cargo load increases.

It is clear that these two examples, similar to the device shown in FIG. 1, increase the steering outputs of P and S4 and reduce the operating resistance of the steering wheel as the live load increases.

Next, PS4 in the above explanation is of a type in which both the pressure in the working chamber and the reaction force in the reaction force chamber affect the reaction force of the steering wheel, that is, belongs to the third type mentioned first. However, FIG. 5 shows an embodiment in which the present invention is applied to P and S in which the reaction force of the steering wheel depends only on the pressure in the reaction force chamber.

A pipe line 2a that supplies pressure oil from the oil pump 1 is a branch valve 2.
5 into a pipe line 2b and a pipe line 2c, and the pipe line 2b is directly connected to the working chamber of the PS4.

The pipe line 2c includes the chamber 8 of the hydraulic reaction force control valve 26, the communication hole 10,
It constitutes a flow path returning from the chamber 9 to the oil pump 1 via the pipe line 4a, and the chamber 8 and the reaction force chambers P and S4 are connected through the pipe line 6.

The configuration of the hydraulic reaction force control valve 26 itself is the same as the configuration of the pressure control valve 3 shown in FIGS. 1 to 4, and the poppet valve 11 that changes the flow path area of the communication hole 10 is shown in FIG. Similar to the above device, its position is controlled via the load detector 12 controller 17 and solenoid 18.

Therefore, in this device, when the load is empty, the poppet valve 11
Since the communication area of the communication hole 10 is minimized and the flow path between the chambers 8 and 9 is narrowed down, the pressure in the chamber 8 is increased.

The pressure in the reaction chambers P and S4, which rise and communicate with the pipe 6, reaches a maximum, and a reaction force corresponding to the reaction chamber pressure is applied to the steering bundle.

At the time of loading, the poppet valve 11 is displaced downward in the figure according to the amount of the loaded load, increasing the communication area of the communication hole 10, so that the pressure in the chamber 8 decreases.

Therefore, a lower pressure is applied to the reaction force chambers P and S4 than when the vehicle is unloaded, and as a result, the operational resistance of the steering bundle is reduced.

FIG. 6 shows an embodiment in which the flow dividing valve 25 of the above embodiment is provided integrally with the pressure control valve 3.

That is, a chamber 8a is provided above the chamber 8 of the flHi pressure control valve 3, which communicates with the chamber 8 via an orifice 19.
This chamber 8a is connected to a pipe line in which the pipe line 2a is branched, and a fluid with a pressure corresponding to the opening degree of the orifice 19 and the poppet valve 11 flows into the working chambers P and S4, and P
A pressure corresponding to the opening degree of the poppet valve 11 is applied to the reaction force chamber S.

It is clear that the same effect as in FIG. 5 can be obtained in this embodiment as well.

In order to change the pressure exerted on the reaction force chamber of PS4 by J, various valve mechanisms and throttle mechanisms can be used.

Figures 7a, b, and c show some examples.
, 4a, and 6 are the pipes 2c, 4a, and 6 in FIG. 5, respectively.
This is the same conduit as 6.

It is clear that in these examples, if each valve body 26, 27, 28 is moved in the direction of the arrow as the loaded load increases, the same effect as the device shown in FIG. 5 can be obtained.

In the embodiment shown in FIG. 8, the present invention is applied to P and S which are not equipped with a reaction force chamber, and the IJ pressure of the oil pump 1 is controlled via the controller 29 according to the output of the load detector 12. It is configured to do so.

Of course, the IJ pressure of the oil pump 1 is controlled so that it becomes higher as the load increases.
If the pressure of the pressurized oil reaching the working chamber is high, the steering output becomes stronger and the operational resistance of the steering bundle becomes smaller.

IJ IJ-fu pressure is controlled, for example, as follows.

In a normal oil pump, setting and adjusting the IJ-F pressure is done by changing the spring force that presses the valve element against the valve seat. The spring seat can be moved negatively in the axial direction of the body, and the position of this spring seat can be adjusted using a solenoid.

Then, the energization of the solenoid is controlled by the outputs of the load detector 12 and the controller 29, so that the higher the live load, the higher the relief pressure.

Note that the position of the spring seat can also be set mechanically.

Next, in the embodiment shown in FIG. 9, a limit reaction mechanism 30 is provided in the middle of the conduit 6 leading to the reaction force chambers P and S4, which changes the upper limit of the steering reaction force depending on the magnitude of the live load. It is.

This mechanism 30 has a valve body 33 slidably disposed in a valve box 31 and having a communication passage 32 for communicating the pipe line 6, and applies a set force of a spring 34 that presses the valve body 33 to a load equal to the load. The spring seat 35 of the spring 34 is connected to a connecting rod 20 erected on the axle 15 via a link 36 pivotally connected to the chassis frame 14. Therefore, as the live load increases, the spring seat 35 moves downward in the figure, and the spring 3 against the valve body 33
The set force of 4 becomes smaller.

Therefore, the pressure in the working chamber increases due to bundle operation,
When this is applied to the reaction force chamber, the valve body 33 descends due to the pressure and cuts off communication with the pipe line 6, so the pressure introduced into the reaction force chambers P and S4 remains constant from then on, but the pressure will be controlled according to the live load.

In the embodiments shown in FIGS. 5, 6, and 8, the load is detected by a load detector 12 that generates an electrical output, which is shown in FIGS. 2 and 4. Of course, it may be replaced with a mechanical or hydraulic/pneumatic load detector such as the one described above.

In the embodiments of the present invention described above, no restrictions are placed on the axles on which the load detectors are provided.

Therefore, although the load may be detected on either the front axle or the rear axle, for the purposes of the present invention it is preferable to detect the loaded weight on the steering axle, ie, usually the front axle.

Further, the load detection is not always carried out, but only once, for example, when the engine is started, and it is also possible to perform the above-mentioned PS load correction from this detected value.

In this sense, even if the load detector and the fluid pressure control means are not directly connected as in the embodiment, and a person manually operates the fluid pressure control means by looking at the output of the load detector, the P and S Load correction can be performed.

When using a constantly sensitive load detector, use a filter pond that removes high-level wave components as described above, a load detector with lower load detection sensitivity or response, or a damper to prevent shock. The load may be measured after the load is removed.

Furthermore, if P and S are classified based on their specific configuration, especially the type of valve used, they can be divided into P and S using spool valves, PS using rotary valves, and P and S using flapper valves. Of course, the present invention can be applied to any type of valve.

In the above embodiment, for convenience of illustration, the pressure control valve is P,
Although it is provided separately from S4 or the oil pump 1, it goes without saying that the pressure control valve can be incorporated into the P, S4 or the oil pump 1 in advance.

As described above, in the steering force control device for a power steering device according to the present invention, the operation reaction force of the steering bundle becomes smaller as the vehicle's live load becomes larger, so it can be used regardless of the size of the live load. This has the effect of always allowing easy bundle operations.

In particular, the present invention is equipped with a fluid pressure control means, which controls the pressure of the fluid guided from the oil pump to the power steering device, and therefore, compared to, for example, controlling the flow rate, it is possible to control the fluid pressure. The responsiveness of the steering wheel is good, that is, the rise of the characteristic curve is steep, and a light steering force can be selected near the neutral position.

In this hydraulic control, the pump discharge pressure increases by the amount of the hydraulic pressure increase during the control, and although this involves energy loss, the magnitude of the steering force can be freely controlled by, for example, selecting the pressure receiving area of the reaction force chamber, etc. It has advantages that can be selected as follows.

[Brief explanation of the drawing]

FIG. 1 is a connection diagram showing an embodiment of the steering force control device according to the present invention, with main parts in cross section, FIG. 2 is a connection diagram showing another embodiment of the present invention, and FIG. Fig. 2 is an enlarged cross-sectional view of part ■, Fig. 4 is a connection diagram similar to Fig. 1 showing an embodiment of the pond of the present invention, and Fig. 5 is a connection diagram showing the working chamber and pressure chamber of the power steering device. A connection diagram similar to FIG. 1 showing an embodiment in which the diverted fluid is guided by a diverting valve, and FIG. 6 a similar connection diagram to FIG. 1 showing an embodiment in which the diverting valve is incorporated into a pressure control valve. Connection diagram,
Figures 7a, b, and c are schematic sectional views showing examples of throttle valve mechanisms for controlling fluid pressure, respectively, and Figure 8 shows an embodiment in which the present invention is applied to a power steering device without a reaction force chamber. A connection diagram showing an example, FIG. 9 is a connection diagram showing an embodiment including a limit reaction mechanism that makes the bundle steering force constant when the live load exceeds a certain value. 1 oil pump, 3: pressure control valve, 4: power steering device, 11: poppet valve, 12: load detector, 26: hydraulic reaction force control valve.

Claims (1)

[Scope of Claims] 1. A power steering device that provides an auxiliary force to the steering force of the steering bundle, a load detector that generates an output according to the loaded load of the vehicle,
and a fluid pressure control means responsive to the output of the load detector, the fluid pressure control means controlling the pressure of the fluid guided from the oil pump to the power steering device according to the magnitude of the live load, A steering force control device for a power steering device, characterized in that the larger the live load, the smaller the reaction force against the steering bundle. 2. The power steering device is equipped with a working chamber that generates a steering output and a reaction force chamber that applies a reaction force to the steering bundle, and the fluid pressure control means controls the pressure of the fluid guided to the reaction force chamber according to the load. The steering force control device for a power steering device according to claim 1, wherein the steering force control device for a power steering device is controlled so that the larger the amount, the lower the steering force. 3. When the power steering device includes a working chamber that generates a steering output, and the magnitude of the steering output determines the reaction force of the steering bundle, the fluid pressure control means controls the pressure of the fluid guided to the working chamber. The steering force control device for a power steering device according to claim 1, wherein the control is performed so that the load increases as the load increases. 4. A steering force control device for a power steering device according to any one of claims 1 to 3, wherein the load detector detects a load applied to a steering shaft of a vehicle. 5. According to any one of claims 1 to 4, the output of the load detector is input to the fluid pressure control means through a filter that removes high frequency components that occur when the vehicle curves or runs on a rough road. Steering force control device for power steering device. 6. The power steering device according to any one of claims 1 to 5, wherein the fluid pressure control means is constituted by a throttle valve mechanism that throttles the flow path from the oil pump to the power steering device. Steering force control device. 7. The steering force control device for a power steering device according to any one of claims 1 to 5, wherein the fluid pressure control means is constituted by a control mechanism that controls the IJ pressure of the oil pump. . 8. Claims 1, 2, 4, or 5, wherein the fluid pressure control means comprises a limit reaction mechanism that determines the upper limit of the pressure introduced into the reaction chamber of the power steering device. A steering force control device for a power steering device according to. 9 The pipe line for feeding pressure oil from the oil pump is branched by a diversion valve, one of the pipes is connected to the working chamber of the power steering device, and the capacity pipe is connected to the hydraulic reaction force control valve. The steering force of the power steering device according to claim 1, 2, 4, or 5, wherein the hydraulic reaction force control valve controls the reaction force chamber pressure of the power steering device. Control device.