JPS5814352B2 - 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 specifically to a novel steering force control device that changes the steering force in accordance with the vehicle load and vehicle speed. It is related to the device.

Power Steering
．． (abbreviated as "s") provides an auxiliary force to the steering force of the steering wheel to enable light steering operation, and so-called integral type, semi-integral type, and linkage type are conventionally 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. Regardless of its type, the S always has 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. depends on how much reaction force is generated to the handle. The classification of S is as follows.

The first one is P. This type determines the magnitude of the reaction force of the steering wheel depending on the magnitude of the pressure in the working chamber that generates the steering output at S, that is, the magnitude of the auxiliary force ratio of the steering force.
．． This is a type in which a reaction force chamber that applies steering resistance to the steering wheel is provided separately from the working chamber of the S, 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 using the auxiliary force dog/and the reaction force size of the reaction force chamber. All of the above three types are P. When the working pressure due to S becomes a dog,
The steering resistance of the steering wheel becomes the dog.

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

For this reason, especially in trucks where the payload changes greatly between empty and loaded, if each element is set so that suitable steering output and reaction force of the steering wheel can be obtained when loaded, then When the vehicle is unladen, the steering wheel becomes too light, resulting in a significant lack of running stability, especially when traveling at high speeds with no load.

On the other hand, if the various elements are set assuming an unloaded state, there is a risk that the steering resistance of the steering wheel becomes too large when the vehicle is loaded.

In view of the above circumstances, the inventor of the present invention, Nagisa et al. In order to obtain more ideal drivability of vehicles equipped with S, especially ideal drivability of trucks whose payload changes greatly between empty and loaded, we have changed the conventional method of steering force according to vehicle speed. In addition to control, P. This focuses on controlling the steering output of the S.

Therefore, the purpose of the present invention is to reduce the reaction force to the steering wheel when the vehicle's live load is small and the vehicle speed is small, and when the live load is small and the vehicle speed is high, the reaction force to the steering wheel is small. The objective is to obtain a steering force control device with a large force.

Another object of the present invention is to prevent the steering resistance of the steering wheel from becoming too light even when traveling at high speed in an empty state.
An object of the present invention is to obtain a steering force control device with excellent high-speed stability.

Another object of the present invention is to provide a device that allows the steering wheel to be operated with less force when traveling at low speed with a load, thereby further reducing driver fatigue.

Yet another object of the present invention is that P. This is to control the fluid pressure, which is the source of the operating pressure for the S and also the source of the reaction force applied to the steering wheel, in accordance with the magnitude of the live load and the magnitude of the vehicle speed.

Next, the purpose of the present invention is described by P. The description for each type of S is as follows.

Type P equipped with a reaction force chamber that applies reaction force to the steering wheel.
．． In S, the pressure in the reaction force chamber is closed to reduce the steering resistance as the ramming load increases and as the vehicle speed decreases.
P. which is equipped with only a working chamber. In S, the live load is dog,
The lower the vehicle speed, the higher the pressure of the fluid that leads to the working chamber.

Furthermore, the pressure in the compartments of the working chamber and the reaction force chamber is used to apply reaction force to the steering wheel. In S, the load N
The purpose is to reduce the pressure in the working chamber and the pressure in the reaction chamber to increase the ratio of auxiliary force to the steering force and reduce the operating resistance of the steering wheel as the vehicle speed decreases. It is something to do.

Another object of the present invention is to increase the P.O. The aim is to reduce horsepower consumption by not producing S output, and to prevent excessive stress and hydraulic pressure from producing P. S
We have improved the wear rate of each sliding part and gear part and the durability of seals by preventing it from occurring in the system, and we have also improved the link mechanism by preventing shocks and vibrations such as kick banks from being excessively suppressed by the handle. The purpose is to protect them.

In order to achieve the above-mentioned object, the present invention has been made by P. 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 vehicle S is intended to be changed in accordance with the magnitude of the payload and the magnitude of the vehicle speed.

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

Figure 1 is a basic configuration diagram of the present invention, in which 1 is an oil pump normally driven by an engine, 2 is a P
．． At P.S, the pressure oil discharged from the oil bomb 1 is controlled by the pressure control valve 3 to a pressure that corresponds to the vehicle speed and the loaded load. S2, and this P. The oil discharged from S2 is returned to the oil pump 1.

Reference numeral 4 denotes a control section of the pressure control valve 3 that controls the pressure control valve 3 according to vehicle speed and payload, and outputs from a vehicle speed detection mechanism 5 that detects the vehicle speed and a load detection mechanism 6 that detects the payload. and controls the pressure control valve 3 according to these outputs, thereby controlling the P. The hydraulic pressure from the oil pump 1 supplied to S2 is controlled so that a comfortable steering feeling can always be obtained.

Although various conventionally known pressure control valves can be used as the pressure control valve 3, P. Type S2, ie P, S which has only a working chamber, and P.S which has a working chamber and a reaction force chamber. S, the bomb 1, pressure control valve 3 and P.S. The method of connecting the piping that communicates between the P.82 and the P.82 is different. Regarding S2, an embodiment is shown in which a variable orifice dog type pressure control valve 3 is used.

In the figure, pressure oil from an oil pump 1 flows into a diverter valve 8 through a pipe line γ, and is divided into two streams by the divider valve 8, one of which flows through a pipe line 9 into a flow pipe. The oil reaches the working chamber side of S2, and further flows back to the oil pump 1 via the conduit 10.

The other flow divided by the diverter valve 8 flows into the pressure control valve 3 via the pipe line 11, and further flows back to the oil pump 1 via the pipe line 12 and the pipe line 10 described above.

The hydraulic pressure, which is controlled by the pressure control valve 3 to a pressure that corresponds to the vehicle speed and the loaded load, is passed through the pipe 13 to the P.
It is installed in the reaction force chamber of S2, so that a comfortable steering feeling can always be obtained regardless of the driving conditions.

The pressure control valve 3 includes a spool valve 16 slidably inserted into a hole 15 of a housing 14 thereof.

An annular groove 11 is carved on the outer peripheral surface of the Nubour valve 16,
When the spring 18 housed in the hole 15 holds the Nupur valve 16 in the left non-operating position shown in FIG.
0 through the annular groove 11 with a sufficient flow path area.

By connecting the annular groove 19 of one force to the conduit 11 and the annular groove 20 of the other force to the conduit 12,
Pressure oil from the oil pump 1 is returned to the oil pump 1 via the pipe 11, the annular grooves 19, 17, 20, and the pipe 12.

Furthermore, by communicating the annular groove 19 with the pipe line 13,
As will be described later, when the Nupur valve 16 is displaced to the right to adjust the overlapping amount L between the annular grooves 19 and 17, that is, the flow area, the hydraulic pressure that increases according to the adjusted amount is
．． It is designed so that it can be introduced into the reaction force chamber of S2.

In this embodiment, the control unit 4 that controls the displacement amount of the Nupur valve 16 of the pressure control valve 3, the vehicle speed detection mechanism 5, and the load detector 6 that provide output to the control unit 4 are as follows:
Each uses mechanical means.

The control section 4 is comprised of a pair of ronds 21 and 22 disposed on both sides of the Nupur valve 16 on the same axis and slidably provided on the housing 14.

The vehicle speed detection mechanism 5 includes a rotating cable 24 pulled out from the output shaft of the transmission 23, and a rotating cable 24 pulled out from the output shaft of the transmission 23.
The centrifugal cabana mechanism 25 is rotationally driven by the rotation of the centrifugal cabana mechanism 25.

The centrifugal governor mechanism 25 includes a pair of arms 21 that rotate around a bin 26 and a weight 28 provided at the tip of each arm 2γ.
4, the centrifugal cabana mechanism 25 is rotated according to the rotation of the output shaft of the transnumission 23, that is, according to the vehicle speed, the centrifugal governor mechanism 25 is The thrust force generated in this case can be transmitted to the Nupur valve 16.

When Rm, the thrust of the centrifugal governor mechanism 25, which increases as the vehicle speed increases, acts to displace the Nupur valve 16 to the right.

The load detection mechanism 6 includes a rod 31 connected to an axle 30 that supports a steering wheel 29. The rod 31 is attached to a leaf nub ring 34 rotatably supported on a chassis frame 32 with a pin 33 as a fulcrum. 35, and the leaf nup ring 34 is connected to the rod 22 via a pin 36.

The position in FIG. 2 shows the maximum load and low speed condition.

When the live load decreases, the leaf nup ring 31 that supports the axle 30 extends and connects the chassis frame 32 and the axle 3.
The rod 31, which is connected to the axle 30 and separated from the rod 30, is displaced downward with respect to the chassis frame 32.

Then, the leaf pull ring 34 connected to the rod 31 rotates clockwise about the pin 33, and the rod 22 connected to the pull valve 16 displaces the pull valve 16 to the right with a force corresponding to the load.

Next, the operation of this embodiment will be explained.

(1) When the vehicle speed is the minimum and the payload is the maximum.

In this case, since the steering resistance is the largest, P. S
It is required that the pressure oil introduced into the second reaction chamber be minimized.

When the vehicle speed is low, the thrust generated by the centrifugal cabana mechanism 25 to urge the Nubour valve 16 to the right is small, and when the load is large, the thrust force generated by the centrifugal cabana mechanism 25 tends to urge the Nubour valve 16 to the left via the rod 22. Since the acting force is large, as a result, the Nupur valve 16 is held at the position shown in the figure, and the overlapping amount L between the annular grooves 19 and 17, that is, the flow area is maximized. In this state, from the pump 1 to Pipe line 1, diversion valve 8,
The oil flowing into the annular groove 19 through the pipe line 11 flows into the annular groove 11 without being throttled, so that the pressure in the annular groove 19 does not increase due to the throttling action.

Therefore, P. The pressure in the reaction chamber of S2 is kept low and almost zero.

The oil that has flowed into the annular groove 17 is further transferred to the annular groove 2.
0, returns to the oil bomb 1 via line 12.10.

On the other hand, P. Pressure oil is supplied to the working chamber side of S2 via the pipe line 1, the diverter valve 8, and the pipe line 9, so the steering wheel 3
8, pressure is generated in the operating chamber to provide an auxiliary force to the steering wheels 29, as is well known in the art.

At this time, as described above, the steering resistance is at its maximum or the oil pressure in the reaction force chamber is kept low, so that the steering wheel can be operated easily.

(II) When the vehicle speed is maximum and the live load is minimum.

In this case, since the steering resistance is the lowest, P. S
The amount of pressure oil introduced into the second reaction chamber is required to be maximum.

When the vehicle speed is at its maximum, the thrust generated by the centrifugal governor mechanism 25 is maximum, and this thrust forces the Nupur valve 16 to the right to narrow the flow path between the annular grooves 19 and 17.

In addition, when the live load is small, the Ronde 22 displaces the Nupur valve 16 to the right, so the annular groove 1
9 and 17 is the minimum, and the annular groove 19, that is, P. The pressure inside the reaction force chamber of S2 becomes maximum.

At high speeds with the least steering resistance and light loads, the steering wheel is relatively heavy and allows for stable steering operation.

(m) When the vehicle speed is the minimum and the live load is the minimum, or when the vehicle speed is the maximum and the live load is the highest, etc.
).

In this case, the steering resistance will be in an intermediate range between the maximum and minimum staves.

When the vehicle speed is low, the force exerted by the rod 21 to displace the spool valve 16 to the right is small; on the other hand, when the load ψ is small, the rod 22 displaces the spool valve 1 to the right.
Try to displace 6 significantly to the right.

At this time, one of the four rods 21 provides resistance to the rightward movement of the Nubourg valve 16 by the other force rod 22, so the amount of rightward movement of the Nubourg valve 16 is between the intermediate position described in (I) and (I) above. value.

On the contrary, if the vehicle speed is high, the rod 21 will try to displace the Nufour valve 16 to the right, but since the load is large, the rod 22 will try to displace the Nufour valve 16 to the left, and as a result, In this case as well, the amount of rightward movement of the Nupur valve 16 is an intermediate value.

When comparing the effect of the size of the live load on steering resistance with the effect of the size of the vehicle speed on the steering resistance, it is generally considered that the effect of the size of the vehicle speed is greater. Set the output to be slightly larger than the output of the load detection mechanism.

As a result, the amount of displacement of the Nubour valve 16 is appropriately controlled according to the vehicle speed and the loaded load, and the amount of displacement of the Nubour valve 16 is properly controlled according to the vehicle speed and the load. S
The hydraulic pressure introduced into the second reaction chamber is also appropriately controlled.

As is clear from the above explanation, P. Since hydraulic pressure controlled according to the vehicle speed and the loaded load is introduced into the S2 reaction chamber, a comfortable steering feeling can always be obtained regardless of the vehicle speed or loaded load.

In the embodiment shown in FIG. 2, mechanical means are used for both the vehicle speed detection mechanism 5 and the load detection mechanism 6, but one or both of them may be replaced by electrical means or means using fluid pressure. Can be replaced.

FIG. 3 shows an electrical vehicle speed detection mechanism 5a.

A solenoid 40 is disposed within a housing 39 integrally connected to the housing 14 of the pressure control valve, and a plunger 41 is slidably inserted into the center hole of the solenoid 40.

In the middle of the rotating cable 43 of the Nupidometer 42 pulled out from the output shaft of the Trannumeron 23, the rotation speed of the rotating cable 43 is detected, and the battery 44 is connected in accordance with the rotation speed of the rotating cable 43.
A control device 45 is provided to control the current flowing from the solenoid 40 to the solenoid 40 .

The plunger 41 is equipped with a V-type rond 2 connected to the Nupur valve 16, and when running at low speed,
When the current flowing to the renoid 40 is small, the plunger 41 is moved to the left by the elastic force of the spring 46, and when the vehicle speed increases and the current flowing to the renoid 40 becomes large, the plunger 41 is moved to the right by the electromagnetic force. This makes it possible to control the force acting on the Nubour valve 16.

FIG. 4 shows an electrical load detection mechanism 6a.

In this figure, a housing 39, a renoid 40, a plunger 41, and a spring 46 are constructed in the same manner as shown in FIG.

41 is a displacement meter or load detector disposed between the chassis frame 32 and the axle 30 or leaf nub ring 31;
The magnitude of the current flowing from the battery 44 to the solenoid 40 is controlled depending on the load, that is, the amount of displacement between the chassis frame 32 and the axle 30 or leaf nup ring 31.

The plunger 41 springs when the live load is small.
6, when the load increases and the current flowing to the lenoid 40 increases, it moves to the left, and the Nubour valve 16 can be moved to the left via the rod 22 connected thereto. can.

Furthermore, FIG. 5 shows a hydraulic speed detection mechanism 5b.

An oil pump 48 provided on the output shaft of the trannumission 23 communicates with a chamber 50 formed in the housing 14 of the pressure control valve through a conduit 49.

A rod 21 is connected to a pinuton 51 forming this chamber 50, and the pinuton 51 is biased to the left by a spring 52.

When the pressure inside the pinhu 48 rises in accordance with the vehicle speed, the pressure is guided into the chamber 50 through the pipe 49, and the pressure inside the pinhu 48 increases.
, displace the Nupur valve 16 via the terminal 21.

FIG. 6 shows a pneumatic load detection mechanism 6b, and the axle 30
is supported by an air spring 53, the air spring 5
This utilizes the pressure change within 3.

The pressure within the air splash 53 is maintained in the chamber 5 constructed similarly to FIG.
0 through conduit 54.

Of course, the speed detection mechanisms 5ar5bs and the load detection mechanisms 6a and 6b of each type described above have substantially the same function as the mechanisms 5 and 6 in the above-described embodiments. It is clear that this can be done.

FIG. 7 shows another embodiment of the present invention, in which a variable orifice dog of a type different from that of the above embodiment is used as the pressure control valve 3a, and the flow dividing valve 8 is omitted.

The diverter valve 8 is originally connected to the P. via a conduit 9. It has the function of always keeping constant the ratio of the amount of oil supplied to the working chamber of S2 and the amount of oil supplied to the pressure control valve 3 via the pipe line 11, but in order to ensure this function, at the same time , has the function of not transmitting pressure changes in one flow path to the other flow path.

In the embodiment shown in FIG. 2, which has the flow divider valve 8, it is sufficient to consider only the pressure leading to the reaction force chamber, but in this embodiment, as will be described later, It is necessary to consider the pressure on both parties.

In this embodiment, the pressure oil discharged from the A-il pump 1 flows through a pipe line 54, a chamber 55 formed in the housing 14a of the pressure control valve 3a, a communication hole 56, and a chamber 51, and further flows through a pipe line 58. Via P. It flows into the working chamber side of S2 and returns to the oil pump 1 via the pipe 59.

A bopppet valve 60 is provided in the housing 14a so as to be movable toward the communication hole 58 from the side of the chamber 5γ. Allows pressure to be controlled.

Therefore, chamber 55 is connected to P. It communicates with the reaction force chamber S2, so that the pressure inside the chamber 55 can be introduced into the reaction force chamber.

However, even in the pressure control valve 3a using the boppet valve 60, the rods 2L. 2
If we provide a rondo corresponding to 2 (see imaginary line in Figure 1),
Various speed and load detection mechanisms 5, 5a, 5b described above
, 6, 6a, and 6b can be used as they are, but in this embodiment, the control section 4a that controls the amount of advance and retreat of the poppet valve 60 of the pressure control valve 3a is of a type that can be electrically controlled. Along with this, the speed detection mechanism 5a' and the load detection mechanism 6a' are also similar to the electric mechanisms 5a and 6a.
In this embodiment, a represents a solenoid 64 in a housing 63 that is integrally connected to the housing 14a of the pressure control valve 3a, a plunger 65 that is slidably inserted into the center hole of this solenoid, and this plunger. and a spring 66 that urges the spring 65 downward.

The poppet valve 60 is connected to a plunger 65 and is normally held in a lower end position by the resiliency of a spring 66 to maximize the flow area between the chambers 55,57.

Reference numeral 67 is a control circuit for controlling the current flowing to the solenoid 64, which receives signals from the vehicle speed detection mechanism 5a' and the load detection mechanism 6a' and causes a current to flow through the solenoid in accordance with the vehicle speed and the loaded load.

The vehicle speed detection mechanism 5a' and the load detection mechanism 6a' are
Since the control section 3a is an electrical control section, unlike the mechanical control section 3 described above, the mechanism of the solenoid 40 is omitted from each mechanism 5a, 6a shown in FIGS. 3 and 4. The other configurations are the same as those of the mechanisms 5a and 6a.

In this embodiment as well, as can be understood from the above embodiments, in order to always obtain a comfortable steering feeling. When the vehicle speed is at the minimum and the live load is at the highest position, the poppet valve 60 is located at the lowest position, and when the vehicle speed is at the maximum and the live load is at the minimum position, the poppet valve 60 is located at the highest position; otherwise, The boppet valve 60 may be located in an intermediate range depending on the vehicle speed and the load.

In order to satisfy this requirement, the output of the vehicle speed detection mechanism 5a' is set to increase as the vehicle speed increases, while the output of the load detection mechanism 6a' is set to increase as the live load decreases.

Then, the control circuit 6γ adds the outputs of both mechanisms 5a' and 68', and causes a current corresponding to the added value to flow through the renoids.

Therefore, if the vehicle speed is the minimum and the payload is the maximum,
The output of the control circuit 6γ becomes the minimum, the poppet valve 60 is positioned at the lowest position due to the elastic force of the spring 66, and the flow path area between the chambers 55 and 57 becomes the maximum, and the P. The pressure inside the reaction force chamber of S2 becomes almost zero.

Conversely, when the vehicle speed is maximum and the load is minimum, the output of the control circuit 67 is maximum, and the boppet valve 60 is in the chamber 55.5.
Narrow down the flow path between P. The pressure inside the reaction force chamber of S2 becomes maximum.

By the way, in this embodiment, a variable orifice canine type pressure control valve is used, and unlike the embodiment shown in FIG. 2, the pressure oil passing through the pressure control valve is transferred to the P.O. Since the pressure is supplied to the working chamber of S, the pressure in the chamber 55, that is, the reaction force chamber, increases as the pressure in the working chamber increases.

Therefore, when the vehicle speed increases or the axle load decreases, the poppet valve 60 moves in the opening direction, and the pressure in the reaction force chamber is selected and determined by the relative balance with the throttling effect of the orifice dog 56. become.

In other words, at high speeds when the poppet valve 60 is closed or when the load is empty, the handle becomes relatively heavy, and the poppet valve 62
The steering wheel becomes relatively light at low speeds when the door opens or when loaded.

In this case, it goes without saying that the throttle amount of the pressure control valve and the output of each detection mechanism may be set in consideration of the pressure to the compartment.

FIG. 8 shows another embodiment in which the pressure control valve shown in FIG. 1 is partially modified.

That is, in this embodiment, a chamber 81 is formed in the housing 14b of the pressure control valve 3b, and the chamber 81 communicates with the chamber 55 through the orifice 80, and the conduits 54 and 58 in FIG. The chambers 55 are communicated with each other, and the chamber 5γ is communicated with the suction side of the oil pump 1 via a conduit 82.

P. Fluid at a pressure corresponding to the opening degree of the orifice dog 80 and the bopento valve 60 is supplied to the working chamber of S2,
p. A pressure corresponding to the opening degree of the popent valve bO is introduced into the reaction force chamber s2.

It is obvious that the same effect as the embodiment shown in Fig. γ can be obtained also in this embodiment using such a pressure control valve 3b.

Next, the control unit 4a in the embodiment shown in FIGS.
The outputs of the speed detection mechanism and the load detection mechanism are electrically added and the poppet valve 60 is controlled accordingly, but based on the same idea, the control section is replaced by a mechanical mechanism. It can be done.

FIG. 9 shows one example in which a centrifugal Gahana mechanism 25 is used as the vehicle speed detection mechanism 5, and a load detection mechanism 6b.
This is combined with a method using an air splash 53.

Of course, other combinations are also possible.

The output of the load detection mechanism 6b is introduced into the chamber 68 as air pressure, and presses down the binuton γ0 against the spring b9.

A poppet valve 60 is connected to this binuton γ0, and therefore, similarly to the case of the electric control unit 4a, this mechanical control unit 4b also displaces the poppet valve 60 with a downward force as the load increases. let

The output of the vehicle speed detection mechanism 5 is transmitted as the thrust of the centrifugal governor mechanism 25 to the cylinder 11 including the pinuton 10, and as the vehicle speed increases, the cylinder 11 resists the spring 12.
to rise.

As a result, when the vehicle speed is the minimum and the live load is the lowest, the boppet valve 60 is located at the highest position, and when the vehicle speed is maximum and the live load is the lowest, the boppet valve 60 is located at the highest position.

FIG. 10 shows still another embodiment of the present invention,
In this embodiment, two pressure control valves 3a using boppet valves 60 are connected in series.

As the vehicle speed detection mechanism 5, one equipped with a centrifugal governor mechanism 25 is used to control one pressure control valve, and as the load detection mechanism 6, a mechanism equipped with a leaf 7 pull 36 is used to control the other pressure control valve. I have to.

The oil pressure discharged from the oil pump 1 flows into the pressure control valve 3a for vehicle speed detection, where it is controlled to a pressure according to the vehicle speed, and then flows into the pressure control valve 3a for load detection.

After the pressure is controlled by the pressure control valve 3a according to the load, the P. The oil is supplied to the working chamber side of S2, and further returned to the oil pump 1.

The bottle 33 constituting the load detection mechanism 6 is provided in a position opposite to that of the pin 33 shown in FIG. 2, so that when the load increases, the poppet valve bO shifts to the stone knife in FIG. 1U.

Once the vehicle speed is the minimum and the load is the maximum,
Both poppet valves 60 each maintain the flow path area to the maximum and keep the pressure to the reaction chamber to the minimum, and at the same time, do not reduce the hydraulic pressure supplied to the working chamber.

On the other hand, when the vehicle speed is maximum and the live load is minimum, both boppet valves 60 each keep the flow area to a minimum, thus keeping the pressure to the reaction chamber at the minimum, and at the same time reducing the pressure to the working chamber. Relatively lower the oil pressure, P. Increase the output ratio of S2 by 1 degree.

When the vehicle speed and load are intermediate between these, the hydraulic pressure to the reaction force chamber and the working chamber becomes the intermediate pressure mentioned above, but the hydraulic pressure introduced to the reaction force chamber is equal to one pressure. When the maximum pressure is obtained by the control valve, that pressure is reached.

Therefore, when the maximum pressure to be introduced into the reaction force chamber is obtained by the pressure control valve for detecting vehicle speed, check valve γ3 is installed to prevent that pressure from escaping to the pressure control valve for load detection. It is set up.

Next, the embodiment shown in FIG. A limit reaction mechanism 3c as a pressure control valve that changes the upper limit of the steering reaction force according to the vehicle speed and the loaded load is provided in the middle of the conduit 90 leading to the reaction force chamber S2.

This mechanism 3c has a valve body 94 slidably disposed in a valve box 92 and having a communication path 93 for communicating and closing a pipe line 90, and a spring 95 that presses the valve body 94 is set to adjust the setting force depending on vehicle speed and load. The spring seat 96 of the spring 95 is connected to the plunger 65 of the control section 4a in the embodiment described above.

Therefore, as the vehicle speed decreases and the load increases, the spring seat 96 moves downward in the figure, causing the spring 95 to move against the valve body 94.
The set force of becomes smaller.

For this reason, the pressure in the working chamber increases when the handle is operated.
When this pressure is applied to the reaction force chamber, the valve body 94 descends due to the pressure and cuts off communication with the pipe line 90, so that the subsequent P. S2
The pressure introduced into the reaction force chamber is constant, but the pressure is controlled according to the vehicle speed and the load.

The above explanation is based on the P.I. Regarding S,
P. without a reaction force chamber. Regarding S, the control oil pressure via the pressure control valve is changed to P. All you have to do is introduce it into the working chamber of S.
In that case, the pressure control valve and the P. Of course, there is no need for a conduit communicating with the reaction force chamber of S.

In addition, if there is no reaction chamber, or if there is a reaction chamber but the working chamber side flow path and the reaction force chamber side flow path are separated by a flow divider valve, the flow path to the working chamber Alternatively, a relief valve as a pressure control valve may be provided in the middle of the flow path to the reaction force chamber.

As is well known, the relief pressure can be adjusted by adjusting the elastic force of the spring that brings the valve body into elastic contact with the valve seat. If the control unit and each detection mechanism are used for control, it is possible to obtain the same effects as those of the above-mentioned embodiments.

In the embodiment of the present invention described above, there is no restriction on the axle on which the load detector is installed. Therefore, the load may be detected on either the front axle or the rear axle, but from the purpose of the present invention, For example, it is preferable to detect the loaded weight at the steering axle, typically the front axle.

In addition, load detection is always performed, for example, once when the engine is started, and from this detected value, the above-mentioned P. It is also possible to perform load correction of S.

In this sense, even if the load detection mechanism and the fluid pressure control valve are not directly connected as in the embodiment, and a person manually operates the fluid pressure control valve by looking at the output of the load detector, the P. S load correction can be performed. In addition, when using a constantly sensitive load detector, a filter 14 for removing high frequency components generated in the displacement meter 41 may be provided as shown in FIG. A lowered load detector or a damper may be used to measure the load after the impact load is removed.

Furthermore, P. If S is classified based on its specific configuration, especially the type of valve used, it can be classified as p. s, P. using low revalve. S and P with flapper valve. It goes without saying that 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 S2 or oil pump 1, the pressure control valve is installed in P. Needless to say, it can be incorporated into the S2 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 reaction force to the steering wheel can be controlled according to the vehicle speed and the loaded load, and therefore, the reaction force against the steering wheel can be controlled depending on the vehicle speed and the loaded load. This has the effect that a comfortable steering feeling can always be obtained regardless of the situation.

In particular, the present invention includes a fluid pressure control valve that controls the pressure of the fluid introduced from the oil pump into the power steering device to control the reaction force against the steering handle. Compared to controlling the flow rate,
The control response is good, that is, the characteristic curve rises steeply, and a light steering force can be selected near the neutral position.

In addition, the flow rate control described above uses the control unit to control the pressure control valve according to two variable factors: vehicle speed and payload, so extremely stable steering is achieved without being affected by these fluctuations. can hold power,
It is possible to perform steering with less fatigue.

In this hydraulic control, the pump discharge pressure increases by the amount of the hydraulic pressure increase during the control, and although this entails a corresponding loss, the magnitude of the steering force can be adjusted by, for example, selecting the pressure receiving area of the reaction force chamber, etc. It has the advantage of being able to choose freely.

[Brief explanation of the drawing]

The drawings all show embodiments of the present invention; Fig. 1 is a basic configuration diagram of the entire device, Fig. 2 is a partial cross-sectional connection diagram showing a specific embodiment of the invention, Figs. 3 and 5. are schematic diagrams showing vehicle speed detection mechanisms with different configurations from the vehicle speed detection mechanism shown in FIG. 2, and FIGS. 4 and 6 are respectively schematic diagrams showing load detection mechanisms with different configurations from the load detection mechanism shown in FIG. 2. FIGS. 1 and 8 are partial cross-sectional connection diagrams showing other embodiments of the present invention, respectively, and FIG. 9 shows a configuration different from the control section shown in FIGS. γ and 8. Cross-sectional view showing the control unit provided, No. 10
11 are partial cross-sectional connection diagrams showing still other embodiments of the present invention. 1; Oil pump, 2: Power steering device, 3, 3as3b
+3cy pressure control valve, 4.4a, 4b; control section, 5+5
as5a'+5b; Vehicle speed detection mechanism・6t6a, 6a',
6b; Load detection mechanism; 38; Steering handle.

Claims (1)

[Scope of Claims] 1. A power steering device that provides an auxiliary force to the steering force of the steering wheel, a load detection mechanism that generates an output that corresponds to the vehicle's loaded load, a vehicle speed detection mechanism that generates an output that corresponds to the speed of the vehicle, A pressure control valve controls the fluid pressure supplied from the oil pump to the power steering device to control the reaction force against the steering handle, and receives the output from each of the above mechanisms to reduce the load to the ground. A steering force control device for a power rudder augmentation device, comprising a control unit that controls the pressure control valve so that the reaction force is small and the reaction force becomes smaller as the speed decreases. 2. A patent in which 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 wheel, and the pressure control valve controls the pressure of the fluid guided to the reaction force chamber. A steering force control device for a power steering device according to claim 1. 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 wheel, the pressure control valve controls the pressure of the fluid guided into the working chamber. A steering force control device for a power steering device according to claim 1, wherein the load detection mechanism detects a load applied to a steering shaft of a vehicle. Steering force control device 05 for a power steering device as described in Claim 1, wherein the output of the load detection mechanism is input to the pressure control valve via a filter that removes high frequency components that occur when the vehicle curves or runs on a rough road. A steering force control device for a power steering device according to any one of items 1 to 4. 6. Steering of a power steering device according to any one of claims 1 to 5, wherein the pressure control valve is constituted by a variable orifice dog mechanism that throttles the flow path from the oil pump to the power steering device. Force control device. A steering force control device for a power steering device according to any one of claims 1 to 5, wherein the γ pressure control valve is constituted by a control mechanism that controls II-F pressure of an oil pump. 8. Claims 1, 2, 4, or 5, wherein the pressure control valve comprises a limit reaction mechanism that determines the upper limit of the pressure introduced into the reaction chamber of the power steering device. Steering force control device for power steering device. 9 The pipe line that supplies pressure oil from the oil pump is branched by a flow divider valve, one pipe line is connected to the working chamber of the power steering device, and the other line is connected to the power steering device via a pressure control valve. A steering force control device for a power steering device according to any one of claims 1, 2, 4 to 8, each connected to a reaction force chamber of the device.