KR20000041607A - Steering device for varying steering rate - Google Patents

Abstract

PURPOSE: A steering device for varying a steering rate is provided to change a rate between a rotational angle of a steering wheel and a switching angle of a wheel based on a travelling state of a vehicle and to miniaturize the device by simplifying a structure and to enhance a manipulation property by reducing the transmission loss. CONSTITUTION: According to a rotation of a steering wheel, the opening degree of a control valve(31) is regulated, and the oil of an oil pump(30) is flowed in one side of a power cylinder(10). Herein, the power cylinder is pushed by the operation pressure of the oil, and pushes an output shaft(20) so that the steering wheel(43) is easily manipulated. The output shaft(20) moves right or left with the operation pressure generated in the power cylinder and a steering force generated as a pinion gear is butted with a rack gear unit(21). Herein, since the steering device passes through a device for varying a steering rate, the rotation speed of the pinion gear is varied and transferred according to the rotation angle of the steering wheel.

Description

Steering Ratio Variable Steering

The present invention relates to a power steering apparatus for a vehicle, and more particularly, to a steering ratio variable steering apparatus that reduces steering wheel responsiveness during high-speed straight driving of a vehicle and increases steering wheel responsiveness in other sections.

In general, the power steering device is for easy steering operation. The oil pump is driven by the engine of the vehicle to generate hydraulic pressure, and the hydraulic pressure is converted into mechanical force to lighten the operating force of the steering wheel. It is a device that enables steering operation.

By the way, such a power steering device has the advantage of excellent operation performance because of a light handle, but when the vehicle is in a high-speed straight running state, the steering force of the steering wheel is too light, so there is a problem of lowering the driving stability.

In order to solve such a problem, in the related art, a steering ratio variable steering device has been developed for changing the steering angle of the wheel with respect to the rotation angle of the steering wheel to ensure the stability of the driving when driving at high speed.

In other words, when the vehicle is in the straight driving state, steering is reduced by reducing steering responsiveness to reduce steering responsiveness, and when the vehicle is in a curved driving state, steering steering is increased again to increase steering responsiveness. It is to raise. Such a conventional steering ratio variable steering apparatus is disclosed in Japanese Patent Laid-Open No. 6-234367 filed in 1994 in Japan.

In the invention disclosed in Japanese Patent Laid-Open No. 6-234367, as shown in FIG. 1, the rack 204 meshed with the pinion 202 connected to the shaft 200A of the handle 200 is axially engaged. The sliding pin 210 coupled to the long hole 208 formed in the swing lever 206 swings the swing lever 206 around the support pin 212. At this time, the output shaft 216 held by the swing lever 206 by the pin 214 is moved in the axial direction, and the wheel 218 is steered.

Thus, by moving the position of the support pin 212 in the direction (Y) orthogonal to the rack 204 and the output shaft 216, the distance W1 between the support pin 212 and the sliding pin 210 and the support pin 212 The ratio between the steering wheel 200 rotation angle and the switching angle of the wheel 218, that is, the steering ratio, can be changed by changing the ratio of the distance between the pin and the pin 214.

However, such a conventional steering ratio variable steering device is provided with a rack 204 which reciprocates in the horizontal direction separately from the output shaft 216, and the rack 204 is moved between the rack 204 and the output shaft 216. As the swing lever 206 is provided to convey the output shaft 216 to the output shaft 216, there is a complicated configuration of the apparatus.

In addition, the rotational motion of the handle 200 is converted to the linear motion of the rack 204, the linear motion of the rack 204 is converted into the rocking motion of the swing lever 206, and the rocking motion of the swing lever 206 is By converting the output shaft 216 into a linear motion, the movement range of each component is large, and the device is not only large, but also has a large power transmission loss.

The present invention is to solve such a problem, an object of the present invention is to change the ratio of the rotation angle of the steering wheel and the switching angle of the wheel according to the driving state of the vehicle, the structure is simple, the device can be miniaturized, It is to provide a steering ratio variable steering device excellent in operability due to low transmission loss.

1 is a view showing the configuration of a conventional steering ratio variable steering apparatus.

2 is a view showing the configuration of a power steering apparatus equipped with a steering ratio variable means according to the present invention.

3 is a cross-sectional view showing the configuration of a steering ratio variable means according to the present invention.

Figure 4 is an exploded perspective view showing the structure of the steering ratio variable means according to the present invention.

5 is a cross-sectional view showing another embodiment of a steering ratio variable means according to the present invention.

Explanation of symbols on the main parts of the drawings

10: power cylinder, 20: output shaft,

21: rack gear part, 22: wheels,

24a, b: tie rod, 25: piston,

30: oil pump, 31: control valve,

40: handle shaft, 41: upper shaft,

42: lower axis, 44: pinion gear,

50: steering ratio variable means, 51: connecting shaft,

52: support member, 55: sliding groove,

56: first connecting pin, 57: variable groove,

58: second connecting pin, 59: guide pin.

The present invention for achieving the above object, the handle shaft is rotated in accordance with the operation of the handle, the output shaft for steering the wheel by linear movement in the axial direction in accordance with the rotation of the handle shaft, and the rotational movement of the handle shaft is In the steering ratio variable steering device provided with a steering ratio variable means in the middle of the handle shaft and the output shaft so that the steering ratio is variable in the process of being transmitted in the linear motion of the output shaft,

The steering ratio variable means includes an upper shaft connected to the handle and a lower shaft connected to the output shaft, the handle shaft configured to be separated from each other, and the upper shaft and the upper shaft to transmit the rotational force of the upper shaft to the lower shaft and to move in the axial direction. A connecting shaft inserted into the lower shaft, a spiral groove formed on an outer surface of the connecting shaft so as to move in the axial direction when the connecting shaft is rotated, and guided by guide pins fixed thereto, and the connecting shaft rotates. The variable shaft to be fitted into the variable groove and the variable groove formed on any one of the lower shaft and the connecting shaft to which the lower shaft is connected so that the lower shaft is rotated at a same speed as the connecting shaft when the shaft is moved in the axial direction. It includes a connecting pin that is fixed to any one of the lower shaft or the connecting shaft is not formed groove A configuration in which the gong.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. 2 is a view showing the configuration of a power steering apparatus equipped with a steering ratio variable means according to the invention, Figure 3 is a cross-sectional view showing the configuration of the steering ratio variable means according to the invention, Figure 4 is a steering according to the invention An exploded perspective view showing the structure of the non-variable means. And, Figure 5 is a cross-sectional view showing another embodiment of the steering ratio variable means according to the present invention.

As shown therein, the power steering apparatus according to the present invention is provided with a cylindrical power cylinder 10 forming a sealed structure, and penetrates the inside of the power cylinder 10 and extends in both sides to one side thereof. The output shaft 20 in which the rack gear portion 21 is formed is installed. Tie rods extending from the knuckles 23a and 23b on the wheel 22 side are provided at both ends of the output shaft 20 extending outward from both ends of the power cylinder 10 so as to steer the wheel by the axial movement of the output shaft ( 24a, 24b are connected to be deflectable.

On the outer surface of the output shaft 20 located inside the power cylinder 10, the inner space of the power cylinder 10 is partitioned on both sides, and the inside of the power cylinder 10 together with the output shaft 20 is linearly reciprocated. Piston 25 is provided. In addition, the oil inflow ports 11a and 11b are formed in the power cylinder 10 so that oil supplied from the oil pump 30 can flow into the inner spaces of both sides of the power cylinder 10 partitioned by the piston 25. do.

In addition, one side of the power cylinder 10, the handle shaft 40 connected to the handle 43 of the vehicle extends therein, the rack gear portion 21 of the output shaft 20 at the end of the handle shaft 40 And a pinion gear 44 to be engaged with it. Therefore, when the handle shaft 40 is rotated, the output shaft 20 is linearly reciprocated from side to side.

At this time, the handle shaft 40 is composed of an upper shaft 41 connected to the handle 43, the lower shaft 42 is connected to the pinion gear 44 and provided with a plurality of refractions (42a, 42b), The connecting portion of the upper shaft 41 and the lower shaft 42 is provided with a steering ratio variable means 50 to be transmitted by varying the number of revolutions of the handle transmitted from the upper shaft to the lower shaft.

In addition, a control valve 31 for determining an inflow direction of oil flowing into the oil inflow ports 11a and 11b of the power cylinder 10 on one side of the handle shaft 42 entering the inside of the power cylinder 10. Is installed. The opening degree of the valve is adjusted according to the rotation direction of the handle 43 so that the oil of the oil pump 30 is supplied to the left port 11a or the right port 11b of the power cylinder 10. This allows the auxiliary power to be generated towards the direction of steering.

On the other hand, the steering ratio variable means 50, as shown in Figures 3 and 4, the upper shaft 41 and the lower shaft 42 is composed of a hollow shaft, the upper shaft 41 and the lower shaft 42 is connected to them At the same time, the connecting shaft 51 of the annular rod that slides up and down is fitted.

On the outer side of the upper shaft 41 and the lower shaft 42 is provided a cylindrical support member 52 which protects their connecting portion and supports the upper shaft and the lower shaft, and the supporting member 52 wraps and supports the outer surface thereof. It is fixed to the vehicle body by the fixing member 53. And support bearings 54a and 54b are installed on the outer surfaces of the upper shaft 41 and the lower shaft 42 supported on the inner surface of the support member 52 so that they can be rotatably supported.

In addition, the upper shaft 41 to which one end of the connecting shaft 51 is fitted, so that the rotational force of the upper shaft can be transmitted to the connecting shaft 51 and the connecting shaft 51 can be slid in the axial direction. A sliding groove 55 is formed to be elongated in the axial direction, and the sliding groove 55 is fitted with a first connecting pin 56 fixed to an outer surface of the connecting shaft 51. That is, the connecting shaft 51 is caught in the sliding groove 55 through the first connecting pin 56 to be able to move in the axial direction along the sliding groove 55.

In addition, the lower shaft 42 into which the other end of the connecting shaft 51 is fitted allows the rotational force transmitted to the connecting shaft 51 to be transmitted to the lower shaft 42, and the connecting shaft 51 in the axial direction. The variable groove 57 formed of the inclined groove 57a and the straight grooves 57b and 57c is formed to allow the rotational speed to be varied while sliding. In addition, the variable groove 57 is fitted with a second connecting pin 58 which is also fixed to the outer surface of the connecting shaft 51. At this time, the inclined groove 57a is formed to be inclined so as to form an angle α that is twisted by a predetermined angle with the axis direction of the lower shaft 42, and the linear grooves 57b and 57c are formed at the upper end and the lower end of the inclined groove 57a. It is formed long in the direction, they are configured to communicate with each other to guide the second connecting pin (58).

At this time, in the present embodiment, sliding grooves 55 and variable grooves 57 are formed on the upper shaft 41 and the lower shaft 42, respectively, and the first and second connection pins 56 and 58 are connected to the connecting shaft 51. Although the fixed grooves and the sliding grooves are formed at both ends of the connecting shaft, respectively, the first connecting pin may be fixed to the upper shaft and the second connecting pin may be fixed to the lower shaft.

In addition, when the connecting shaft 51 is rotated by the rotation of the upper shaft 41 in the central portion of the connecting shaft 51, the spiral groove 51a on the outer surface so that the connecting shaft 51 can be advanced or retracted in the axial direction. Is formed, and one end of the guide pin 59 fixed to the inner surface of the support member 52 is coupled to the spiral groove 51a. That is, the connecting shaft 51 is in the state that the spiral groove (51a) is caught in the guide pin 59, when the rotation is moved in the axial direction.

At this time, it is preferable that the inclination angle α with respect to the axis of the inclined groove portion 57a of the variable groove 57 forms an angle smaller than the inclination angle β of the spiral groove 51a. When the α and β are the same, the motion path of the second connecting pin 58 moving in the axial direction while rotating and the guiding direction of the inclined groove 57a become the same so that the connecting shaft 51 rotates to move forward. Even if the rotation of the lower shaft 42 is not generated, if the α is greater than β because the problem that the lower shaft 42 is limited in the axial movement is reverse rotation.

The following describes the operation of the steering ratio variable steering apparatus according to the present invention configured as described above.

When the driver rotates the handle to the left or right, the opening degree of the control valve 31 is adjusted so that the oil of the oil pump 30 flows into one side of the power cylinder 10. At this time, the piston 25 inside the power cylinder 10 is pushed by the operating pressure of the oil, by pushing the output shaft 20 in the direction to operate the handle 43 to facilitate the operation of the handle 43 do.

At the same time, the output shaft 20 is a steering force generated by the engagement of the pinion gear 44 and the rack gear portion 21 provided at the end of the handle shaft 40 as well as the operating pressure generated in the power cylinder 10. Is added to move left or right.

At this time, the steering apparatus according to the present invention, since the rotational force of the handle 43 is passed through the steering shaft 40 to the pinion gear 44 through the steering ratio variable means 50 installed in the middle, the handle 43 The rotational speed of the pinion gear 44 is variable and transmitted according to the rotation angle.

That is, when the upper shaft 41 rotates in any one direction, the rotational force of the upper shaft 41 is transmitted to the connecting shaft 51 through the first connecting pin 56 so that the connecting shaft 51 and the upper shaft 41 are rotated. It will be rotated at the same rotation speed. At this time, the connecting shaft 51 is rotated forward or backward in the axial direction while rotating because the spiral groove (51a) formed on the outer surface of the center portion is caught on the guide pin (59).

Therefore, since the second connecting pin 58 fixed to the lower shaft 42 is moved forward or backward while performing a helical movement, the inclined groove 57a of the variable groove 57 is pushed in the rotational direction along the inclined groove 57a. Will proceed. At this time, since the sliding occurs between the inclined groove 57a and the second connecting pin 58, the rotational direction of the lower shaft 42 is the same as the connecting shaft 51, but the rotational speed is reduced.

Then, when the connecting shaft 51 is continuously rotated so that the second connecting pin 58 moves along the straight grooves 57b and 57c provided at the upper and lower portions of the variable groove 57, the connecting shaft 51 and the lower shaft 42. Is rotated at the same rotational speed.

That is, the steering ratio variable means 50 according to the present invention, when the second connecting pin 58 is located in the inclined groove portion 57a and the wheels 22 of the vehicle are in a substantially straight driving state, the rotation of the lower shaft 42 is performed. When the output shaft 20 is slowly moved because the speed is decelerated, and the handle 43 is rotated a lot on either side of the left and right, the second connecting pin 58 is positioned at the linear grooves 57b and 57c, and the lower shaft 42 and The rotational speed of the connecting shaft 51 is the same, so that the movement of the output shaft 20 is faster.

As described above, the steering apparatus according to the present invention has a slow movement in the center section and a rapid movement at both sides due to the rotation of the steering wheel, so that the response of the steering wheel is reduced when the vehicle is in a high speed straight driving state, thereby ensuring stability of the driving. When the vehicle rotates, the response becomes faster and the steering busyness can be eliminated.

On the other hand, Figure 5 shows another embodiment of the steering ratio variable means 50 according to the present invention, the upper shaft 41 'and lower shaft 42' constituting the handle shaft 40 is composed of a rod-shaped shaft , The connecting shaft 51 'connecting them is composed of a hollow shaft. An axial sliding groove 55 'is formed at one end of the connecting shaft 51' connected to the upper shaft 41 ', and the other end of the connecting shaft 51' connected to the lower shaft 42 '. A variable groove 57 'consisting of an inclined groove 57a' and a straight groove 57b ', 57c' is formed, and the spiral groove 51a 'is formed on the outer surface of the central portion of the connecting shaft 51' as in the above-described embodiment. ) Is formed. In addition, the first connecting pin 56 ′ fitted into the sliding groove 55 ′ is fixed to the upper shaft 41 ′, and the second connecting pin 58 ′ fitted into the variable groove 57 ′ is the lower shaft ( 42 ').

The other embodiments shown here start from the basic idea of the present invention, and have been performed with only slight modifications in the constituent parts, and most operations are the same as the above embodiments.

As described in detail above, the steering ratio variable steering apparatus according to the present invention, even if the upper shaft and the connecting shaft rotates at the same rotational speed, the rotational speed of the lower shaft is variable, so that the steering wheel responsiveness during high-speed straight driving of the vehicle is inferior The stability of the operation is secured, and when the vehicle is traveling in a curve, the response is faster, and thus steering can be eliminated. Further, the steering ratio variable means of the steering ratio variable steering apparatus according to the present invention is simpler in structure than the conventional configuration, the volume and movement range is small, the device can be miniaturized, as well as its manufacturing cost and installation is easy This has the advantage of low power transmission loss.

Claims (6)

The steering shaft rotates according to the manipulation of the handle, the output shaft for steering the wheel by linear movement in the axial direction according to the rotation of the handle shaft, and the steering ratio in the process of transmitting the rotational movement of the handle shaft to the linear movement of the output shaft. In the steering ratio variable steering device provided with a steering ratio variable means in the middle of the handle shaft and the output shaft so that the variable transmission can be, The steering ratio variable means 50 is provided with a hollow shaft and the handle shaft 40 is formed by separating the upper shaft 41 and the lower shaft 42 connected to the output shaft 20 is connected to the handle, the upper shaft The connecting shaft 51 is inserted into the hollow portion on the upper shaft and the lower shaft to transmit the rotational force of the shaft to the lower shaft and to be movable in the axial direction, and the connecting shaft moves in the axial direction when the connecting shaft is rotated. A spiral groove 51a formed on an outer surface of the connecting shaft so as to be guided by a fixed guide pin 59, and when the connecting shaft is moved in the axial direction while the connecting shaft is rotated, the lower shaft is decelerated to rotate or the same as the connecting shaft. The lower shaft 42 which is connected to the lower shaft 42 and the connecting shaft 51 so that they can be rotated at a speed and the lower shaft that the variable groove is not formed to fit into the variable groove 57 Steering ratio variable steering apparatus comprises a connecting pin (58) fixed to the connecting axle load either side. The method of claim 1, In the connecting portion of the upper shaft 41 and the connecting shaft 51, a sliding groove 55 formed long in the axial direction on either side of the upper shaft or the connecting shaft, and the sliding groove is formed so as to be fitted to the sliding groove. Steering ratio variable steering device, characterized in that it comprises a connecting pin (56) which is fixed to any one of the upper shaft or the connecting shaft. The method of claim 1, The variable groove 57 is an inclined groove portion 57a formed to be distorted in the axial direction of the lower shaft, and a straight groove portion 57b and 57c communicating with the inclined groove portion and extending in an axial direction from upper and lower ends of the inclined groove portion. Steering ratio variable steering device comprising a. The steering shaft rotates according to the manipulation of the handle, the output shaft for steering the wheel by linear movement in the axial direction according to the rotation of the handle shaft, and the steering ratio in the process of transmitting the rotational movement of the handle shaft to the linear movement of the output shaft. In the steering ratio variable steering device provided with a steering ratio variable means in the middle of the handle shaft and the output shaft so that the variable transmission can be, The steering ratio variable means 50 is a handle shaft 40 is formed by separating the upper shaft 41 'connected to the handle and the lower shaft 42' connected to the output shaft 20, and the rotational force of the upper shaft A connecting shaft 51 ′ provided with a hollow shaft fitted to the upper shaft and the outer surface of the lower shaft to be transferred to the lower shaft and to be movable in the axial direction, and when the connecting shaft is rotated, the connecting shaft in the axial direction. A spiral groove 51a 'formed on an outer surface of the connecting shaft to be moved and guided by a fixed guide pin 59, and the lower shaft is decelerated to rotate or the connecting shaft when the connecting shaft is moved in the axial direction while the connecting shaft is rotated. The lower shaft or the connecting shaft is not formed with the variable groove to be fitted to the variable groove (57 ') and the variable groove formed on either side of the lower shaft and the connecting shaft to which they are connected to be rotated at the same speed as Steering ratio variable steering, characterized in that it comprises a connection pin (58 ') is fixed to any one side. The method of claim 4, wherein A connection groove between the upper shaft 41 'and the connecting shaft 51' has a sliding groove 55 'formed in an axial direction on either side of the upper shaft or the connecting shaft, and the sliding groove is fitted into the sliding groove. Steering ratio variable steering device, characterized in that it comprises a connecting pin (56 ') fixed to any one of the upper shaft or the connecting shaft is not formed. The method of claim 1, The variable groove 57 'is an inclined groove 57a' formed to be distorted with the axial direction of the lower shaft 42 ', and is in direct communication with the inclined groove and extends in an axial direction from upper and lower ends of the inclined groove. A steering ratio variable steering apparatus comprising grooves (57b ', 57c').