JPH04135972A - Reaction control mechanism for power steering device - Google Patents

Abstract

PURPOSE:To keep manufacturing cost low by forming recessed sections for each side surface faced to plungers, permitting a pin to abutt against the outer walls of the recessed sections when the pin of a stub shaft is rotated, and thereby concurrently constituting the both outer ends of the pin to creep into each recessed section of the plungers. CONSTITUTION:The side surfaces faced to each other of plungers 15 through 18 are formed with recessed sections 28 each diameter (s) of which is of a specified standard dimension, When a pin 19 is rotated, the pin 19 abutts against each inner circumferential corner section 30 of projected sections 29, so that the both outer tip end sections of the pin 19 projected out of each corner section 30 are made to creep into each diagonal position, for example, each recessed section 28 of the plungers 16 and 17. When the diameter of each recessed section 28 is formed, for example, into a diameter (t) smaller than a standard one (s), the pin 19 abutts against the circumferential corner section 31 when the pin 19 is rotated, a rotating radius r2 for steering reaction becomes larger than a rotating radius r1 for steering reaction, so that steering reaction can thereby be made heavy. When the difference in steering reaction at the time of switch-over in steering between the right and the left exceeds a specified value, each diameter of the recessed sections of the plungers 15 through 18 may be adjusted in diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reaction force control mechanism for a power steering device that selectively supplies pressure oil to a power cylinder in accordance with input rotation of a steering wheel.

(Prior Art) In the conventional device shown in FIGS. 4 to 6, a worm shaft 3 is provided on one side of a gear case 1 in which a piston 2 is housed. Further, a stub shaft 4 rotatably supported by a gear case l is inserted into the worm shaft 3, and these two shafts are connected via a torsion bar 5.

The stub shaft 4 is provided with a rotary valve 6 that rotates with the stub shaft 4, and a rotary sleeve 7 is fitted around the outer periphery of the rotary valve 6.

Note that this rotary valve 6 and rotary sleeve 7 constitute a control valve (2).

Further, a large diameter portion 8 is formed on the stub shaft 4 side of the worm shaft 3, and the rotary sleeve 7 is fitted around the outer periphery of this large diameter portion 8.

The large-diameter portion 8 constructed as described above includes a reaction force chamber 9 and 10.11.
and form 12. The reaction force chambers 9 and 10.
11 and 12 are arranged in series in a direction perpendicular to the axis of the worm shaft 3, and the reaction force chambers 9, 10, 11
Stoppers 13 and 14 are protruded between and 12.

Furthermore, plungers 15 to 18 are provided in the reaction chambers 9 to 12.
It's decorated. Each of these plungers 15 to 18 has side surfaces facing each other flat, and
Under the action of the pressure of the hydraulic oil, it is normally brought into pressure contact with the stopper 13, 14. A pin 19 formed integrally with the stub shaft 4 is placed between the plunger 15 and the plunger 16 and between the plunger 17 and the plunger 18, and this pin 19 and the stopper 13
．． The axis line with 14 is made to match.

On the other hand, on the lower side of the gear case l, a supply passage 20 is formed which communicates with the pump P via a pump port P1, and a return passage 21 which communicates with the tank T via a tank port P2 is formed.

Then, the pump P is communicated with one of the chambers R, R2 divided on the left and right sides of the piston 2 via a control valve V that is switched according to the rotation of the handle a, and the pump P is communicated with one of the chambers R, R2 divided on the left and right sides of the piston 2, The chamber is communicated with tank T.

Further, an oil chamber 22 is defined between the outer periphery of the large diameter portion 8 and the gear case I, and this oil chamber 22 is connected to the reaction force chambers 9 to 12.
They communicate with each other, and also communicate with the supply passage 20 via a passage 23 and an orifice 24.

In the passage 23 provided as described above, a passage 25 is formed which branches from the passage 23, and this passage 25 is communicated with the return passage 21 via a switching valve 26. Further, a stepping motor M is connected to the switching valve 26, and a vehicle speed sensor S is connected to the stepping motor M via a controller C.

The output signal of the vehicle speed sensor S is output to the stepping motor M via the controller C, and the opening degree of the switching valve 26 is controlled in accordance with the output signal of the vehicle speed sensor S. That is, the opening degree of the switching valve 26 becomes large during low-speed running, and the opening degree becomes small during high-speed running.

Now, if the handle a is rotated to rotate the pin 19 clockwise in FIG. and move. Like this plunger 16.17
When the movement occurs, the hydraulic oil in the reaction force chamber 1O1ll flows out into the return passage 21 via the oil chamber 22 - passage 23 -> passage 25 -> switching valve 26.

At this time, if the vehicle is running at a low speed, the opening degree of the switching valve 26 is large, so the throttle resistance is almost negligible.Therefore, the handle a can be rotated lightly. When driving at high speed, selector valve 2
6 becomes smaller and the throttle resistance increases accordingly, the pressure within the reaction force chamber 10.1 increases, which becomes a reaction force against the rotational force of the stub shaft 4. and,
Since this stub shaft 4 is connected to the handle a, the pressure in the reaction force chamber 10.11 is ultimately transmitted to the handle a as a steering reaction force.

When the handle a is rotated to rotate the pin 19 counterclockwise, the plunger 15.18 located on the other diagonal will resist the pressure of the hydraulic fluid in the reaction chamber 9.12. While moving, the plunger 16.17 abuts the stopper 13.14 under the pressure of the hydraulic fluid and is held in that position.

When the plunger 15.18 moves against the pressure of the hydraulic oil, the switching valve 26 functions to control the pressure of the hydraulic oil in the reaction force chamber 9.12 in accordance with the vehicle speed.

The pressure within this reaction force chamber 9.12 becomes a reaction force against the rotational force of the stub shaft 4, and is transmitted to the steering wheel a as a steering reaction force. The same is true.

In addition, the reference numeral 33 in the figure is a sector shaft, 34 is a pitman arm, and 35 is a wheel, and the handle a
The amount of movement of the screwdriver 2 that moves in response to the switching is transmitted to the heavy wheels 35 via the sector shaft 33 and the pitman arm 34, so that the wheels 35 are steered.

Then, rotate handle a as described above, and press pin 1.
When the pin 9 is rotated clockwise, for example, the pin 19 rotates around the axial center O of the stub shaft 4. When the pin 19 rotates in this manner, the left and right corner portions 27 and 27 of the pin 19 come into contact with plungers 1617 located diagonally, as shown in FIG. Also, if you turn it counterclockwise (not shown),
Each of the end corner portions 32.32 of the pin 19 abuts a diagonally located plunger 15.18.

In other words, since the plunger 15~]81J'' and the side surface facing the pin 19 are formed into a flat surface, when the pin 19 is rotated, the corner portions 27 or 32 at both ends of the pin 19 are formed as described above. , abutting the opposite plunger 16.17 or one plunger 15.18 1
The radius of rotation r of the pin 19 is determined according to the length of the pin 19, and the radius of rotation r does not change even if the pin 19 rotates clockwise or counterclockwise.

(Problems to be Solved by the Present Invention) In the reaction force control mechanism of the conventional power steering device as described above, in FIG. A. If the pressure of the hydraulic oil in each reaction chamber 9 to 12 controlled via the control valve ■ is p, then the steering reaction force transmitted to the handle a is AXp
The relationship is (θ8, ■)×r.

Note that θ□ represents the valve operating angle of the control valve V, and ■ represents the vehicle speed, indicating that the pressure of the hydraulic oil and the force p are functions of the valve operating angle and the vehicle speed.

On the other hand, since the above-mentioned steering reaction force must be equal to the steering reaction force transmitted to the steering wheel during left-right switching steering, each component in the reaction force control mechanism 1 that operates during left-right switching steering, such as a control The valve operating angle θ□ of valve ■ had to function uniformly from left to right.

For this purpose, the parts and hydraulic pressure of the reaction force control mechanism are
These elements had to be made to a high level of precision so that they would work evenly when steering left and right.

Further, if the steering reaction force during left/right switching steering is different and the difference exceeds a standard value, this is adjusted in the assembly and adjustment process of the reaction force control mechanism. However, since the radius of rotation r of the pin 19 remains the same no matter whether it is rotated clockwise or counterclockwise, the only way to make adjustments is to replace the control valve (2) and the worm shaft 3.

As a result of the above, there is a problem in that the number of man-hours for machining and assembly and adjustment increases, resulting in an increase in manufacturing costs.

An object of the present invention is to provide a reaction force control mechanism for a power steering device that can keep manufacturing costs low. It is two.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a piston inside a gear case, and a worm shaft having one end screwed to the piston, and a stub shaft rotatable relative to the other end of the worm shaft. The worm shaft and the stub shaft are connected by a torsion bar, and a control valve is provided on one side of the gear case to guide pressure oil from a hydraulic source to either the left or right side of the piston. In addition, the control valve is configured to switch according to the rotation of the handle, and the stub shaft is provided with a pin in a direction perpendicular to its axis, and the other end of the worm shaft is provided with a plurality of reaction force chambers. In the reaction force control mechanism of the power steering device, the reaction force control mechanism is configured such that a plunger is formed in the reaction force chamber, and the pin is located between the plungers facing each other, and a recess is formed on the opposite side surface of the plunger,
When the pin provided on the stub shaft rotates, the pin comes into contact with the four outer walls, and both outer ends of the pin are inserted into the recess of the plunger.

(Operation of the present invention) As described above, a recess is formed on the opposing side surface of the plunger, and when the pin provided on the stub shaft rotates, the pin abuts the outer wall of the recess, and the outer ends of the pin are connected to the plunger. Since it is configured to fit into the recess of the
When the stub shaft is rotated, the pin comes into contact with a portion of the inner corner of the outer wall.

Therefore, the radius of rotation of the steering reaction force acting on the pin can be adjusted by changing the diameter of the recess.

In other words, if the steering reaction force transmitted to the handle a differs during left-right switching steering, the diameter of the recess formed in the plunger may be adjusted depending on the manner in which the steering reaction force differs.

(Effects of the present invention) As described above, when the difference in the steering reaction force transmitted to the steering wheel a exceeds the standard value during left/right switching steering,
It is only necessary to adjust the diameter of the recess formed in each plunger according to the manner in which the steering reaction force differs. There is no need to achieve high precision.

Further, as described above, since the diameter of the recess formed in each plunger can be adjusted, there is no need to replace the control valve or even the worm shaft during the assembly and adjustment process of the reaction force control mechanism.

As a result of the above, the number of man-hours for machining and assembly adjustment is not increased (as a result, manufacturing costs can be kept low).

Furthermore, by changing the diameter of the recess formed in each plunger, the radius of rotation of the pin can be changed as desired.

Therefore, it is possible to adjust the steering reaction force for each plunger, and it is possible to equalize the steering reaction force during left-right switching steering with higher precision, and it is also possible to adjust the absolute value of the steering reaction force. can.

(Embodiment of the present invention) In the embodiment of the present invention shown in Figs. 1 to 3, the plungers 15, 16 and 17, 18 have the same axis on the opposing sides of the plungers 15, 16, and 17, 18, respectively. A circular recess 28 is formed, and the outer wall of this recess 28 serves as a protrusion 29.

That is, as shown in FIG. 2, a recess 28 having a predetermined diameter S as a standard dimension is formed on the opposing side surfaces of the plungers 15 to 18, and when the pin 19 rotates, the pin 19 is inserted into the projection 29. At the same time, the pin 19 comes into contact with a portion 30 of the inner peripheral corner, and the outer image tip portion where the pin 19 protrudes from the corner portion 30 is diagonally opposed to, for example, a plunger 16, 17.
It is designed to fit into the recess 28 of. Since everything other than the above is completely the same as that of the prior art, reference will be made to FIG. 4.5 of the prior art, and the same components as those of the prior art will be given the same reference numerals and detailed explanations will be omitted.

As described above, when the pin 19 rotates, the pin 19 comes into contact with a part 30 of the inner peripheral corner of the protrusion 29 formed on the plunger, so when the stub shaft 4 is rotated, the pin 19 is acted upon. The rotation radius r1 of the steering reaction force is determined according to the size of the diameter S of the recess 28.

That is, if the diameter of the recess 28 is formed to a diameter t smaller than the standard diameter S, for example, as shown in FIG.
When the pin 19 rotates, the pin 19 comes into contact with a portion 31 of the inner peripheral corner of the protrusion 29, and the rotation radius r2 of the steering reaction force at this time becomes larger than the rotation radius r1 of the steering reaction force. . Therefore, the steering reaction force can be increased accordingly.

In addition, contrary to the above, if the diameter S is thicker than the standard diameter (formed), the rotation radius of the steering reaction force at this time will be smaller than the rotation radius r of the steering reaction force, and the steering reaction force will be reduced accordingly. can do.

In other words, the steering reaction force during left/right switching steering is different,
If the difference exceeds the standard value, the diameter of the recesses formed in the plungers 15 to 18 may be adjusted in accordance with the manner in which the steering reaction force differs during the assembly and adjustment process of the reaction force control mechanism. Become.

Therefore, the parts and oil pressure of the reaction force control mechanism are
There is no need for these to be highly accurate so that they function uniformly during left/right switching steering.

Further, as described above, since the diameter of the recess formed in each plunger can be adjusted, there is no need to replace the control valve or even the worm shaft during the assembly and adjustment process of the reaction force control mechanism.

Because of the above, the number of man-hours for machining and assembly adjustment does not increase, and as a result, manufacturing costs can be maintained at a low level.

Furthermore, by changing the diameter of the recess formed in each plunger, the radius of rotation of the pin can be changed as desired.

Therefore, it is possible to adjust the steering reaction force for each plunger, and it is possible to equalize the steering reaction force during left/right switching force steering with higher precision, and to adjust the absolute value of the steering reaction force. You can also do it.

[Brief explanation of the drawing]

Figures 1 to 3 of the drawings show this embodiment. Figure 1 is an enlarged sectional view of the main part, and Figure 2 is an explanation showing the relationship between the pin and its rotation radius when the diameter of the recess is formed to a standard size. Figure 3 is an explanatory diagram showing the relationship between the pin and its rotation radius when the diameter of the recess is changed from the standard dimension in order to adjust the rotation radius in Figure 2, and Figures 4 to 6 show the conventional mechanism. 4 is a sectional view, and FIG. 5 is an enlarged view of the main part of the cross section taken along line V-V in FIG. 4.
FIG. 6 is an enlarged sectional view of the main part. 1--Gear case, 2--Piston, 3--Worm shaft, 4--Stub shaft, 5--Torsion bar, ■--Control valve, a--Handle,
19--Pin, 9-12--Reaction force chamber, 15-18-
...Plunger, 28-...4 parts. Missing) Illustration 2/y Large illustration... 2g Oni 3 bacteria/?

Claims (1)

[Claims] A piston is housed in a gear case, one end of which is screwed to the piston, and a stub shaft is fitted to the other end of the worm shaft so as to be relatively rotatable, and the worm shaft and the stub shaft are connected by a torsion bar. A control valve is provided on one side of the gear case for guiding pressure oil from a hydraulic source to either the left or right side of the piston, and the control valve is configured to be switched according to rotation of a handle, and the stub shaft A pin is provided in the direction perpendicular to the axis of the worm shaft, a plurality of reaction force chambers are formed on the other end side of the worm shaft, a plunger is housed in the reaction force chamber, and the pin is connected between the opposing plungers. In the reaction force control mechanism of the power steering device, a recess is formed on the opposing side surface of the plunger, and when a pin provided on the stub shaft rotates, the pin abuts against an outer wall of the recess. , a reaction force control mechanism for a power steering device configured such that both outer ends thereof are immersed in a recessed portion of a plunger.