JPS6328760A - Steering device for vehicle equipped with bevel gear - Google Patents

Abstract

PURPOSE:To reduce vibration being transmitted to a steering wheel upon occurrence of shimmy, by controlling a drive means such that the force for pushing a friction block is increased when a resonant condition of the steering wheel is detected. CONSTITUTION:When shimmy is detected by an acceleration sensor 23 for detecting the lateral acceleration of a tierod of a rack shaft, the duty ratio of drive pulse is increased by a control unit 22 on the basis of a detected signal. Consequently, the quantity of relief oil being fed from a relief oil path 20 is reduced and the pressure of oil in an oil chamber 16 and a head side oil chamber 15 is increased to a predetermined level. As a result, a friction block 13 is pressed with a considerably large force against an endface 10a of an input shaft bevel gear 10, thereby an input shaft 4 is restricted by a frictional force functioning between the friction block 13 and the endface 10a even if a resonant vibration is transmitted from a front wheel to an output shaft 4 thus preventing transmission of vibration to a steering shaft 3.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a steering device for an automobile equipped with a bevel gear.

(Prior art) Conventionally, in cab-over type automobiles, etc., it is difficult to arrange the rank shaft of the steering linkage mechanism orthogonally near the extension line of the steering wheel shaft. A rotary operation force direction conversion mechanism is provided, and is connected to a rear steering linkage mechanism via a connecting shaft extending in the front-rear direction.

An automobile steering device equipped with this type of bevel gear is also described in, for example, Japanese Utility Model Application Publication No. 60-28569.

As described in the above-mentioned publication, the above-mentioned steering device alleviates the kickback and shock that propagates from the front wheels to the steering wheel shaft via the steering linkage mechanism and connecting shaft, and also prevents the shaking of the steering wheel due to the backlash of the hevel gear. To reduce friction, it is common to provide a friction block that comes into contact with the small-diameter end of the input shaft bevel gear connected to the handle shaft, and to press this friction block against the gear end with an adjustment screw or disc spring. be.

On the other hand, when a car is running, the front wheels, which are the steering wheels, are misaligned,
Due to various factors such as mechanical rattling in the steering system or suspension system, incorrect tire pressure, and wear conditions, the front wheels begin to resonate in the longitudinal direction (so-called shimmy phenomenon), and this vibration is transmitted to the steering system's steering wheel. In many cases, vibrations propagate in the direction of rotation, causing problems with steering. The above-mentioned shimmy depends on the characteristics of the vehicle, but generally occurs at low speeds, for example, about 10 km/Hr, and at high speeds, for example, about 100 km/Hr.

(Problems to be Solved by the Invention) As described above, in the mechanism in which the friction block is pressed against the end face of the input shaft bevel gear using an adjustment screw or a disc spring, the frictional force by the friction block is adjusted according to the driving condition of the vehicle. It cannot be adjusted, but can only be adjusted via an adjustment screw when the vehicle is assembled or repaired.

If the Fj friction force caused by the friction block becomes excessive, it will become difficult to change the handle and it will be difficult to mark the line.However, the pressing forces of the adjustment screws and countersunk springs are set to be relatively small.

In this case, it is absolutely impossible to suppress the strong vibrations propagated from the steering linkage mechanism to the handle shaft when shimmy occurs using the frictional force of the friction block.

(Means for Solving the Problems) An automobile steering device equipped with a bevel gear according to the present invention includes an input shaft bevel gear provided at an end of an input shaft connected to a steering wheel shaft, and an input shaft bevel gear provided at an end of an output shaft connected to a steering wheel shaft. A steering device for an automobile, comprising: an output shaft bevel gear that is provided and meshes with the input shaft bevel gear; and a friction block that abuts a small-diameter end surface of at least one of the human power shaft bevel gear and the output shaft bevel gear. A driving means for pressing and driving is provided on the end face, a detecting means is provided for detecting a resonance state in the longitudinal direction of the steered wheel while the vehicle is running, and the friction block is pressed when a resonance state occurs upon receiving a detection signal from the detecting means. A control means is provided for controlling the driving means so as to increase the pressing force.

Incidentally, if necessary, the driving means may be constituted by a hydraulic cylinder provided at the back of the friction block, and the friction block may be pressed by a piston rod of the hydraulic cylinder, or alternatively, the driving means may be constituted by a solenoid. It may also be configured with a type actuator.

(Function) Suspension of an automobile equipped with a bevel gear according to the present invention.
In a pension device, a rotational operating force from a handle shaft is transmitted to an input shaft, direction-changed by an input shaft bevel gear and an output shaft bevel gear, and transmitted to an output shaft, and then transmitted from the output shaft to a steering linkage mechanism.

a friction block that comes into contact with the small-diameter end face of at least one of the input shaft bevel gear and the output shaft bevel gear; a drive means that presses and drives the friction block; a detection means that detects a longitudinal resonance state of the steered wheel; and control means for controlling the drive means, and when the detection means detects a resonance state of the steered wheels,
Based on the detection signal, the control means controls the driving means so that the pressing force for pressing the friction block increases. Therefore, when a resonance condition occurs, the bevel gear that the friction block is in contact with is bound by the frictional force that acts between the bevel gear and the friction block, and the resonance vibration that propagates to the handle shaft is significantly reduced. At the same time, the vibration of the front wheels is controlled via the steering system by the restraining force of the friction system, which improves straight-line stability.

(Effects of the Invention) According to the automobile suspension device equipped with the hevel gear according to the present invention, as explained above, the existing friction block is effectively utilized, and the drive means, the detection means, and the control means have a simple configuration. As a result, the vibration transmitted to the handle when shimmy occurs can be significantly reduced.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

This embodiment is an example in which the present invention is applied to a steering device for a cab-over type automobile.

As shown in FIG. 1, this steering device includes a steering handle 1 and a steering shaft 3 connected to the steering handle 1 and extending downward within a column 2.
an input shaft 4 connected to the lower end of the steering shaft 3; an output shaft 5 connected to the lower end of the input shaft 4 via a bevel gear mechanism; and a connecting shaft 6 connected to the output shaft 5 and extending rearward. , a pinion shaft 7 connected to the connecting shaft 6, a pinion at the rear end of the pinion shaft 7, a rank shaft 8 disposed in the vehicle width direction and meshing with the pinion, and a ball joint at both ends of the rack shaft 8. Left and right 1 connected to each other via int
It basically consists of a pair of tie rods and a knuckle arm that is connected to the outer end of each tie rod via a ball joint and integrally projects from the front wheel support member.

Figure 2 shows the configuration of the bevel gear mechanism and its attached equipment. The input shaft 4 and the output shaft 5 have bearings installed in the gear box 9 with their axes forming an opening angle of about 60 degrees. The hell gear 10 is rotatably attached to the input shaft at the lower end of the input shaft 4, and the output shaft hell gear 11 at the front end of the output shaft 5 meshes with each other, so that the rotational scraping force from the input shaft 4 changes direction. and is transmitted to the output shaft 5.

A cylindrical cylinder forming portion is integrally provided in a portion of the gear box 9 facing the small diameter side end surface 10a of the input shaft bevel gear 10 and protrudes outward, and a small hydraulic cylinder 12 is provided within this cylinder forming portion, The piston rod 1
The piston rod 2a protrudes into the gearbox 9 and extends perpendicularly to the end surface 10a, and a friction block 13 made of metal with excellent wear resistance is attached to the tip of the piston rod 12a. It is in contact with the vicinity of the outer periphery of the end surface 10a.

A compression coil spring 14 is installed in the rod side chamber of the hydraulic cylinder 12, and an oil chamber 16 connected to the head chamber oil chamber 15 is connected to a discharge port of a hydraulic pump 17 through a hydraulic pressure supply path 18, and the piston of the hydraulic cylinder 12 is connected to a hydraulic pressure supply path 18. The friction block 13 can be pressed against the input shaft bevel gear 10 by the rod 12a. This pump 17 is driven by a pulley 19 connected to the crankshaft of the engine, and a relief oil passage 20 branching from this oil pressure supply passage 18 is provided with a solenoid valve 21 for adjusting the amount of relief oil. is controlled by a control unit 22, and a signal from an acceleration sensor 23 is output to the control unit 22.

The acceleration sensor 23 is used to detect when shimmy occurs when the vehicle speed reaches approximately 1100k/Hr, causing the front wheels to resonate in the longitudinal direction.If shimmy occurs, the knuckle arm Since the tie rod and the rack shaft 8 begin to vibrate in the vehicle width direction through the vibration, the acceleration sensor 23 is attached to the tie rod and the rack shaft 8 so as to be able to detect the acceleration in the vehicle width direction.

The solenoid of the solenoid valve 21 is a duty solenoid, and the control unit 22 includes an A/D converter that A/D converts the detection signal from the acceleration sensor 23, a microcomputer, and a control i'[ from the microcomputer.
It consists of a drive circuit that outputs drive pulses to the solenoid based on the II signal. A predetermined control program is input and stored in the microcomputer in advance, and as shown in Fig. 3, when shimmy does not occur, the S
This controls the amount of relief oil so as to maintain the oil pressure in the oil chamber 16 at a predetermined relatively low pressure, and when shimmy occurs, increases the duty ratio of the drive pulse (by increasing the duty ratio of the oil chamber 16 and head side oil). The amount of relief oil is controlled so that the oil pressure in the chamber 15 rises rapidly.

When the shimmy is resolved and the front wheels no longer resonate, the amount of relief oil is increased again to maintain the oil pressure in the oil chamber 16 and the head side oil chamber 15 at a predetermined relatively low pressure.

However, the solenoid is configured with a normal solenoid, and the control unit 22 is configured with an acceleration sensor 23, for example.
A circuit that converts the acceleration signal from the input into a voltage signal corresponding to the absolute value of acceleration, a comparison circuit, and a circuit that energizes the solenoid when the absolute value of acceleration reaches the magnitude of the acceleration when shimmy occurs for a predetermined period of time or more. It can also be configured with an analog circuit including a drive circuit and the like.

Additionally, the hydraulic cylinder 12 may be provided so as to face the small-diameter end face of the output shaft bevel gear 11 and may be configured to press the friction block against the end face.

In the above configuration, when shimmy does not occur, the control unit 22 reduces the duty ratio of the drive pulse based on the detection signal from the acceleration sensor 23, increases the amount of relief oil from the relief oil passage 20, and increases the amount of relief oil from the oil chamber 16.
Since the hydraulic pressure in the head side oil chamber 15 is maintained at a predetermined relatively low pressure, the friction block 13 is pressed against the end surface 10a of the input shaft bevel gear 10 with a relatively small pressing force from the piston rod 12a. . As a result, the kickback and shock propagated to the input shaft 4 are moderated, similar to the friction pro-tsuk of the conventional device, and the backlash of the input shaft 4 due to buff crash between the input shaft bevel gear 10 and the output shaft bevel gear 11 is also reduced. Become.

On the other hand, when shimmy occurs, it is detected by the acceleration sensor 23, and based on the detection signal, the control unit 22 increases the duty ratio of the drive pulse and reduces the amount of relief oil from the relief oil path 20. As a result, the oil pressure in the oil chamber 16 and the head-side oil chamber 15 is increased to a predetermined pressure, so that the friction block 13 is pressed against the end surface 10a of the input shaft bevel gear 10 with a considerably large force. As a result, even if the resonant vibration from the front wheel propagates to the output shaft 4, the input shaft 4 is restrained by the frictional force acting between the friction block 13 and the end surface 10a, so the resonant vibration is transmitted to the handle shaft 3. It almost never spreads. At the same time, vibrations in the front wheels are also suppressed through the steering system, improving the straight-line stability of the vehicle.

However, since steering is necessary even when the shimmy occurs, the oil pressure of the hydraulic cylinder 12 is set so that the pressing force does not become excessive.

In the above embodiment, the occurrence of shimmy is detected by directly detecting the acceleration of the rack shaft or tie loft using the acceleration sensor 23, but shimmy may occur depending on the alignment of the front wheels of the automobile, the front suspension characteristics, etc. Since the vehicle speed at this time is approximately constant (approximately 1100 k/Hr), the acceleration sensor 23 is omitted and the solenoid valve 21 is configured to be controlled based on the vehicle speed signal from the vehicle speed sensor when the vehicle speed reaches the shimmy generation vehicle speed. Good too.

In addition, a solenoid type actuator is provided in place of the hydraulic cylinder 12, and when shimmy does not occur, the friction block 13 is pressed against the input shaft bevel gear 10 by a spring force such as a disc spring, but when shimmy occurs, the control unit 22 A driving current may be outputted from the solenoid actuator to the solenoid of the solenoid actuator to strengthen the pressing force of the friction block 13 by the solenoid actuator.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention. Fig. 1 is a side view of the main parts of a steering device for a cab-over type automobile, Fig. 2 is a configuration diagram of a bevel gear mechanism and its attached equipment, and Fig. 3 is a diagram of a hydraulic cylinder. It is a line diagram showing oil pressure. 1. Handle, 2. Column, 3. Steering shaft (steering shaft), 4. Input shaft, 5.
・Output shaft, 6...Connection shaft, 7...Pinion shaft, 8
... U-Tsuku axis, 10... Human power shaft bevel gear,
10a...Small diameter side end face, 11...Output shaft, ll
a...Small diameter side end face, 12...Hydraulic cylinder, 1
2a... Piston mouth/throat, 13... Friction pro, 17... Hydraulic pump, 21... Solenoid valve, 22... Control unit, 23...
Acceleration sensor.

Claims (3)

[Claims] (1) An input shaft bevel gear provided at the end of the input shaft connected to the handle shaft, an output shaft bevel gear provided at the end of the output shaft and meshing with the input shaft bevel gear, and the above input shaft bevel gear and output shaft bevel gear. A steering device for an automobile, comprising: a friction block that abuts on the small-diameter end face of at least one of the gears, comprising: drive means for pressing the friction block against the end face of the gear; and a control means for controlling the driving means so that the pressing force for pressing the friction block increases when a resonance state occurs in response to a detection signal from the detection means. An automobile steering device equipped with a bevel gear characterized by. (2) The bevel gear according to claim 1, wherein the driving means is constituted by a hydraulic cylinder provided at the back of the friction block, and the piston rod thereof is configured to press the friction block. Steering device for automobiles. (3) A steering device for an automobile equipped with a bevel gear according to claim 1, wherein the driving means is constituted by a solenoid actuator.