JPH02216365A - Small angle steering device - Google Patents

Abstract

PURPOSE:To make it possible to apply a publicly known power steering gear by interposing an oval gear mechanism between a steering wheel and a power steering mechanism and an acceleration mechanism between the oval gear mechanism and the power steering mechanism, in the case of a device interposing the oval gear mechanism in a steering power transmitting route. CONSTITUTION:An upper end of an input shaft 3 of an oval gear mechanism 2 is connected by serration to a lower end of a steering shaft 1. This oval gear mechanism 2 is constituted by housing in a casing 5 the first oval gear 4 fixing the input shaft 3 in a position offset in the direction of a major axis and the second oval gear 6 fixing an output shaft 7 in a position similarly offset in the direction of the major axis. Now in a condition that a steering wheel is placed in a neutral position, the first oval gear 4 is set in its minimum diameter part so as to be engaged with the maximum diameter part of the second oval gear 6. And the output shaft 7 of the oval gear mechanism 2 is connected to an inner valve 9 of a power steering gear through a planet gear mechanism 8 constituting an acceleration mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an improvement in a small steering angle steering device that reduces the steering angle required for full steering of the steering wheels.

(Prior Art) Steering devices commonly used for automobiles require the steering wheel to be rotated more than once before the steering wheel is steered to the maximum steering angle, which is useful for people who frequently drive, such as professional drivers. For those who do this, operating the steering wheel is one of the causes of fatigue.

For this reason, various types of small steering angle steering devices have been proposed to obtain a large steering wheel steering angle with a small number of steering wheel operations. In order to simply meet these demands, the steering gear ratio can be set high as in a four mirror car. However, simply increasing the gear ratio causes the steering response to become too sensitive when the steering wheel is near neutral, causing a problem that it becomes difficult to perform corrective steering operations, especially when driving at high speeds.

The present applicant has proposed Utility Model Application No. 63-55845 as a small steering angle steering device that can overcome these problems. This uses an elliptical gear mechanism to obtain a steering characteristic in which the gear ratio increases as the steering angle of the steering wheel increases.
This reduces the steering angle required to fully steer the steered wheels while preventing the steering response from becoming too sensitive near the neutral position of the steering wheel. More specifically, an elliptical gear mechanism is interposed in the steering force transmission path that transmits the rotation of the steering wheel to the steering gear box, and the shortest diameter of the first elliptical gear of the elliptical gear mechanism connected to the steering wheel side. and the longest diameter part of the second elliptical gear connected to the steering gear box are configured so that they mesh with each other when the steering wheel is in a neutral state,
The above requirements could be met with a simple configuration.

(Problem to be Solved by the Invention) However, the small rudder angle steering device described above does not take into consideration the application of a power steering device.

When a power steering mechanism is applied to such a small steering angle steering device, it is desirable to be able to use a conventionally used power steering mechanism, mainly from the viewpoint of cost or reliability.

(Means for Solving the Problems) The present invention solves the above problems by interposing an elliptical gear mechanism in the steering force transmission path that transmits the rotation of the steering wheel to the steering gear box. The shortest diameter part of the first elliptical gear connected to the wheel side and the longest diameter part of the second elliptical gear connected to the steering gear box are configured to mesh with each other when the steering wheel is in a neutral state. In the steering angle steering device, the elliptical gear mechanism is interposed between the steering wheel and the power steering mechanism, and an increaser for speeding up the output of the elliptical gear mechanism is further provided between the elliptic gear mechanism and the power steering mechanism. This is achieved by intervening a speed mechanism.

(Function) According to the present invention, the output of the elliptical gear mechanism is increased in speed by the speed increasing mechanism and transmitted to the power steering mechanism, so even if the maximum steering angle of the steering wheel is decreased, the power steering mechanism does not require manual input. The maximum rotation angle can be the same as that of a conventionally commonly used steering device, and the conventional power steering device and steering gear box can be used as they are.

(Example) Hereinafter, an example of the present invention will be described in detail based on the accompanying drawings.

1 to 5 show a first embodiment of the present invention.

FIG. 1 shows a longitudinal sectional view of the main part of the device. In FIG. 1, the lower end of a steering shaft 1 connected to a steering wheel (not shown) is connected to an elliptical gear mechanism 2.
Serrations are connected to the upper end of the input shaft 3 of the input shaft 3. The first elliptical gear 4 of the elliptical gear mechanism 2 is fixed and prevented from rotating on the outer periphery of the human power shaft 3 inside the casing 5, and the human power shaft 3 is offset from the center of the first elliptical gear 4 in the major diameter direction. It is placed in the same position. The second elliptical gear 6 that meshes with the first elliptical gear 4 within the casing 5 is fixed and prevented from rotating around the outer periphery of an output shaft 7 disposed within the casing 5 in parallel to the input shaft 3.

Note that the output shaft 7 is arranged at a position offset from the center of the first elliptical gear 4 in the longer diameter direction, similarly to the human power shaft 3. In addition, the elliptical gear mechanism 2, as shown in FIG.
With a steering wheel (not shown) in a neutral position, the shortest diameter portion of the first elliptical gear 4 and the longest diameter portion of the second elliptical gear 6 mesh with each other. For this reason,
As the rotation of the human power shaft 3 increases as the steering angle of the steering wheel increases, the gear ratio of the elliptical gear mechanism 2 increases. In this embodiment, the maximum steering angle of the steering wheel is set to about half a turn, so the gear ratio does not become low when the steering angle is large.

The output shaft 7 of the elliptical gear mechanism 2 is connected to an inch valve 9 of a power steering device via a planetary gear mechanism 8, as shown in FIG. That is, a planetary gear carrier 10 for the planetary gear mechanism 8 is integrally formed at the lower end of the output shaft 7.
A plurality of planetary gears 11 are rotatably supported. The ring gear 12 of the planetary gear mechanism 8 is connected to the casing 5
It is fixed to and always meshes with the planetary gear 11. Further, a sun gear 12 of the planetary gear mechanism 8 is fixed to the outer periphery of the upper end of the inner valve 9, and is constantly meshed with the planetary gear 11.

This planetary gear mechanism 8 constitutes a speed increasing mechanism that speeds up the rotation of the output shaft 7 and transmits it to the inner valve shaft 9. That is, in addition to the revolution component of the planetary gear 11, the rotation component is transmitted to the sun gear 12, thereby increasing the speed of the sun gear 12.

Therefore, the steering angle characteristic set by the elliptical gear mechanism 2 is accelerated and manually applied to the power steering mechanism.

Moreover, the above-mentioned inner valve 9 constitutes a well-known rotary valve together with an outer valve 13 arranged on the outer circumferential side. A steering output shaft 14 connected to the lower end of the T-shaped valve 13 is connected to the inner valve 9 via a torsion bar 15. A pinion gear 16 provided on the outer periphery of the steering output shaft 14 is provided to mesh with a rack gear 18 provided on the steering rod 17, and constitutes a steering gear box 19. Note that the configuration of the power steering device and the steering gear box 19 including the inner valve 9 and below are all well-known, and further detailed explanation will be omitted.

Here, the reaction force applying mechanism 20 provided on the input shaft 3 will be explained. The cam body 21 is formed integrally with the first elliptical gear 4 , is disposed below the first elliptical gear 4 , and rotates together with the input shaft 3 . A roller 22 biased by a spring force is pressed against a cam surface formed on the outer periphery of the cam body 21.

That is, a cylindrical spring housing 23 is provided in the casing 5 with its axis oriented in a direction perpendicular to the axis of the human power shaft, and two coil springs 24 and 25 with different spring constants are installed in the spring housing 23. It is stored. The reaction force piston 26 is slidably provided in the spring housing 23, and is biased toward the human power shaft 3 by coil springs 24 and 25.

A roller support plate 27 integrally formed with the reaction force piston 26 is arranged to protrude from the inner end of the spring housing 23, and has a support shaft 28 arranged parallel to the input shaft 3 at its tip. .

A roller 22 made of resin is rotatably supported by this support shaft 28, and is pressed against the cam body 21 by urging force from springs 24 and 25. Further, the cam body 21 is formed in a substantially bard shape as shown in FIG. 3, and is arranged so that the shortest diameter portion is in contact with the roller 22 when the steering wheel (not shown) is in the neutral position. Therefore, the effective radius of the portion of the cam body 21 that contacts the roller 22 increases as the input shaft rotates as the steering angle increases. Note that, since the maximum rotation of the human power shaft 3 is set to about half a rotation, the effective radius of the cam body 21 does not decrease significantly when the steering angle is large.

Next, the operation of this embodiment will be explained.

Steering human power from the steering wheel is transmitted to the planetary gear mechanism 8 via the human power shaft 3, the first elliptical gear 4, the second elliptical gear 6, and the output shaft 7, and is accelerated by the planetary gear mechanism 8 and sent to the steering gear box. 19. In the elliptical gear mechanism 2, the shortest diameter part of the first elliptical gear 4 and the longest diameter part of the second elliptical gear 6 mesh with each other, so that as the rotation of the human power shaft 3 increases, the elliptical gear The gear ratio of mechanism 2 is high. Therefore, as can be easily understood from the steering angle characteristics of this embodiment shown in FIG. The initial response of the wheels is set to be the same as that of conventional models, but as the steering wheel angle increases, the response of the steered wheels becomes quick.And such steering angle characteristics are set. By doing so, it is possible to significantly reduce the maximum steering angle of the steering wheel to about half a turn.

In addition, in the reaction force applying mechanism 20, the effective radius of the portion of the cam body 21 that contacts the roller 22 increases as the input shaft rotates, so that the springs 24 and 25 are gradually compressed accordingly.

Therefore, the biasing force of the springs 24 and 25 acting on the roller 22 via the reaction force piston is
1) increases with the rotation of the shaft, and the pressing force of the roller 22 against the cam body 21 increases with the rotation of the human shaft. As a result, the rotational resistance of the human power shaft 3 increases as the steering angle increases, and the steering force for operating the steering wheel further increases as the steering angle increases.

FIG. 5 shows the steering force characteristics when this reaction force applying mechanism 20 is provided and when it is not provided. In FIG. 5, even when the reaction force imparting mechanism 20 is not provided, the steering force increases as the steering angle increases, which is a characteristic obtained by changing the gear ratio of the elliptical gear mechanism. In this case, the steering force will be larger overall, which will alert the driver, and the difference in steering force between near neutral and near the maximum steering angle will also be larger, preventing the steering angle from increasing due to careless operation. You can prevent it from being put away. Also, as is clear from Figure 5,
When the steering wheel is turned back, the reaction force applying mechanism 20 acts in a direction to reduce the steering force, so that the steering wheel is turned back easily.

Note that the steering force characteristics by the reaction force applying mechanism 20 shown in No. 5 rIA are just an example, and if the spring constant and cam shape of the spring of the reaction force applying mechanism 20 are changed, the steering force can be changed, for example, between near neutral and near the maximum steering angle. The steering force characteristics can be changed in various ways, such as by increasing the force difference.

According to the first embodiment, by providing the reaction force applying mechanism 20, the steering force characteristic can be set independently of the steering force characteristic obtained by the elliptical gear mechanism 2, and the setting of the elliptical gear mechanism 2. This provides the effect that the steering force characteristic can be corrected to the optimum one by setting the reaction force applying mechanism 20 while obtaining the optimum steering angle characteristic. And with this,
This reduces the steering wheel steering angle up to the maximum steering angle, thereby improving the operability of the steering system, while preventing the steering response from becoming too sensitive near neutral and also preventing sudden steering due to careless steering operations. It has the effect of improving

In addition, the output of the elliptical gear mechanism 2 is increased in speed by the planetary gear mechanism 8 and inputted manually to the power steering device.
Even if the maximum steering angle of the steering wheel is reduced, the maximum rotation angle manually applied to the power steering device can be made almost the same as that of commonly used steering devices, and the conventional power steering device and steering gear box can be used as is. It can be repurposed. Therefore, there is an advantage that a small steering angle device with bower swaying can be obtained with a simple configuration and at low cost.

Furthermore, since the cam body 21 of the reaction force applying mechanism 20 is approximately heart-shaped, and the roller 22 is pressed against the shortest diameter part of the cam body when in neutral, it is easy to feel the neutral position of the steering wheel. At the same time, an automatic return function to the neutral position is achieved, making it easier to manipulate the steering wheel and improving stability when traveling straight.

6 to 8 show a second embodiment of the present invention.

In the second embodiment, members that are substantially the same as those in the first embodiment are given the same reference numerals, and detailed explanation thereof will be omitted.

In the second embodiment, compared to the first embodiment, the human power axis 3 is
The positions of the output shaft 7 and the output shaft 7 are reversed, and the human power shaft 3 is arranged coaxially with the steering output shaft 14. For this reason,
In place of the planetary gear mechanism 8 of the first embodiment, a large-diameter helical gear 31 connected to the human power shaft and a small-diameter helical gear 32 connected to the input valve 9 are used. In this embodiment, these helical gears 31, 32
constitutes a speed increasing mechanism, and the rotation of the output shaft 7 is increased in speed by helical gears 31 and 32 and input to the input valve 9.

Further, as reaction force applying mechanisms, a first reaction force applying mechanism 33 and a second reaction force applying mechanism 34 are provided.

The first reaction force applying mechanism 33 is constituted by a mainspring spring 35 arranged around the input shaft 3 and provided between the human power shaft 3 and the casing 5.

The mainspring spring 35 is elastically deformed by the rotation of the human-powered shaft 3, so that its biasing force increases with the rotation of the human-powered shaft 3, thereby increasing the rotational resistance of the human-powered shaft 3. Therefore, the first reaction force applying mechanism 33 alone can provide substantially the same effect as the reaction force applying mechanism 33 of the first embodiment.

In the second reaction force applying mechanism 34, a cam body 21 having the same shape as in the first embodiment is fixed to the output shaft 7, and a roller 22 is in pressure contact with this cam body 21. The major differences from the reaction force applying mechanism 20 of the first embodiment are as follows.
The point is that the force acting on the roller 22 pressed by the cam body 21 is not a biasing force from a spring but a hydraulic force.

For this reason, the casing 5 is provided with a plunger 36 that is slidably arranged in a direction perpendicular to the output shaft 7.
A roller 22 is rotatably supported at the tip of the plunger 3. The hydraulic pressure supplied from the input port 37 provided in the casing 5 acts on the rear end of the plunger 36, and the force with which the roller 22 presses the cam body 21 changes depending on the manually applied hydraulic pressure. It becomes. Note that since the cam body 21 has the same shape as in the first embodiment, as long as hydraulic pressure is supplied from the human-powered boat 37, the rudder angle will not increase as in the first embodiment. There is no change in the fact that it also exerts the effect of increasing the steering force.

FIG. 7 shows a mechanism for generating hydraulic pressure supplied from the human-powered boat 37. An oil pump 42 that sucks and discharges oil stored in an IJ f-button tank 41 is rotationally driven by a speedometer driven gear provided on a transmission output shaft.

Therefore, the oil pump 42 rotates at a rotational speed corresponding to the vehicle speed, and the discharge flow rate increases as the vehicle speed increases. A discharge port of the oil pump 42 is connected to the human-powered boat 37 via an oil path 43.

An oil passage 44 connected to the reserve tank 41 is connected to the oil passage 43, and the oil passage 44 is provided with a throttle 45. Therefore, due to the flow resistance generated by the throttle 45, hydraulic pressure is generated upstream of the throttle 45 according to the flow rate, and since the oil pump 42 discharges oil at a flow rate corresponding to the vehicle speed, this hydraulic pressure is proportional to the vehicle speed. It will rise. Therefore, hydraulic pressure responsive to vehicle speed acts on the input port 37. The IJ IJ valve 46 is used to return part of the oil discharged when the flow rate of the oil pump exceeds a predetermined value to the reserve tank 41, and prevents excessive hydraulic pressure from acting on the human-powered boat 37. It has become something to do.

Here, the operation of the second embodiment will be explained.

In particular, in the second reaction force applying mechanism, the hydraulic pressure input to the input port 37 is sensitive to the vehicle speed, so the force with which the roller 22 presses the cam body 21 increases as the vehicle speed increases. Become. Therefore, the rotational resistance of the human power shaft increases as the vehicle speed increases, and as shown in FIG. 8, it is possible to obtain vehicle speed-sensitive steering force characteristics in which the steering force increases as the vehicle speed increases. Furthermore, due to the shape of the cam body 21, as in the case of the first embodiment, the steering force increases as the steering angle increases, so the steering wheel is not operated with a considerably large steering force during high-speed driving when high oil pressure is supplied. As far as possible, the steering wheel will not be significantly steered due to careless steering operation, and safety will be further improved.

Furthermore, when the vehicle is running at low speed, the steering force is hardly controlled by the second reaction force applying mechanism 34, but the mainspring spring 35 of the first reaction force applying mechanism 33 controls the steering force independently of the settings of the elliptical gear mechanism 2. It is possible to set a characteristic that increases the steering force in accordance with an increase in the steering angle.

According to the second embodiment, in addition to obtaining the same effects as the first embodiment, it is also possible to obtain favorable characteristics as a steering device in which the steering force increases as the vehicle speed increases. + The IJ song becomes more suitable, and there is an effect of more reliably preventing sudden steering due to careless steering operation.

Furthermore, like a normal steering device, the input shaft 3 and the steering output shaft 14 are arranged on the same axis, so the device of this embodiment can be used in place of a normal steering device without modifying the vehicle body. It has the advantage of being easy to install on a vehicle and having a wide range of applications, such as when using a normal type steering device and a small steering angle type steering device depending on the vehicle specifications.

Note that also in the first embodiment, the spring housing 2
By forming a hydraulic chamber between the bottom of the spring retainer 51 and the spring retainer 51 and introducing hydraulic pressure responsive to vehicle speed, vehicle speed sensitive characteristics similar to those of the second embodiment can be obtained.

Furthermore, it goes without saying that the present invention is not limited to the above-mentioned embodiments, and that various other modifications are possible.

(Effects of the Invention) As described above in detail with the embodiments, according to the present invention, a speed increasing mechanism for speeding up the output of the elliptical gear mechanism is interposed between the elliptical gear mechanism and the power steering mechanism. By doing so, it becomes possible to use the conventional power steering device and steering gear box as they are, so that a small steering angle device with power steering can be obtained with a simple configuration and at low cost.

[Brief explanation of the drawing]

1 to 5 show a first embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view of the device, FIG. 2 is a plan view of the elliptical gear mechanism, and FIG. 3 is a plan view of the reaction force applying mechanism. , Fig. 4 is a steering angle characteristic diagram, Fig. 5 is a steering force characteristic diagram, and Figs. 6 to 8 show a second embodiment of the present invention. The figure is a schematic configuration diagram of the hydraulic pressure supply system, and FIG. 8 is a diagram showing steering force characteristics with respect to vehicle speed. 2... Elliptical gear mechanism, 4... First elliptical gear 6...
Second elliptical gear, 20... Reaction force applying mechanism 33... First
Reaction force applying mechanism. 34...Second reaction force applying mechanism s2 drawing Applicant: Mitsubishi Jibō Car Industries, Ltd. s3 drawing ζ

Claims (1)

[Claims] An elliptical gear mechanism is interposed in the steering force transmission path that transmits the rotation of the steering wheel to the steering gear box, and the elliptical gear mechanism connects the shortest diameter part of the first elliptical gear connected to the steering wheel side and the steering gear box. In a small steering angle steering device configured such that the longest diameter part of a second elliptical gear connected to the steering wheel engages with the steering wheel in its neutral state, the elliptical gear mechanism is connected to the steering wheel and the power steering mechanism. A small steering angle steering device, further comprising a speed increasing mechanism interposed between the elliptical gear mechanism and the power steering mechanism, which increases the speed of the output of the elliptical gear mechanism.