JPH0719062U - Electric power steering device for vehicles - Google Patents

Abstract

(57) [Abstract] [Purpose] The electric motor 41 and the speed reducer 39 for power assisting the steering force are provided at a position far from the tie rods 5 of the steering mechanism 1 so that the electric power steering device can be mounted on the vehicle body. improves. [Structure] The steering mechanism 1 has a pitman arm 13
The target link type steering link mechanism using is adopted. At the rear end of the pitman arm 13, an electric motor 41
The actuator unit 19 provided with the speed reducer 39 is located. That is, the steering force from the steering wheel 21 is detected by the torque sensor, the electric motor 41 is rotated, and the pitman arm 1 is rotated around the rotary shaft 15 via the speed reducer 39.
3, the relay rod 9 and the tie rod 5 are moved left and right, and the knuckle arm 3 steers both wheels 2.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electric power steering control device for assisting steering force by an electric motor.

[0002]

[Prior art]

 As a conventional electric power steering device, for example, there is one described in Japanese Patent Laid-Open No. 62-191267. This device is a rack-and-pinion type steering gear mechanism with an actuator unit equipped with an electric motor, speed reducer, and torque sensor. That is, the steering force from the steering wheel is detected by the torque sensor, and the power assist is performed by the electric motor according to the magnitude of the torque. The rotating force of the electric motor is transmitted to the pinion gear via the reduction gear. The pinion gear meshes with the rack gear and moves the tie rod provided with the rack gear to the left and right to perform steering.

[0003]

[Problems to be solved by the device]

 However, the actuator unit that power assists the steering force is provided near the rack and pinion gear. For this reason, this device would increase the size of the vicinity of the tie rod where the rack and pinion gear is provided, and the mountability on the vehicle body would deteriorate. The present invention has been made to solve the above problems, and an object of the present invention is to provide an electric power steering device for a vehicle or the like, which does not have a large size near the tie rod and can be easily installed.

[0004]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides an actuator unit that detects the steering force by a torque sensor and power-assists the rotation speed of an electric motor that is reduced by a reducer to output from an output shaft, and a knuckle arm for both wheels. A steering rod mechanism in which a tip end of a pitman arm is connected to a relay rod that connects both tie rods connected to each other and the rear end serves as a rotation axis and is rotated by a steering force. The output is transmitted to the rotating shaft of the steering link mechanism.

[0005]

[Action]

 The actuator part will be installed near the rotation axis at the rear end of the pitman arm. Then, when the steering force is detected by the torque sensor, the electric motor outputs it from the output shaft via the speed reducer to rotate the rotating shaft at the rear end of the pitman arm. This rotation moves the relay rod and tie rod to the left and right to steer both wheels via the knuckle arm.

[0006]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, a target link type steering link mechanism 1 using a pitman arm is adopted as the steering mechanism of the present embodiment. That is, each tie rod 5 is rotatably connected to a knuckle arm 3 provided on each of the wheels 2 by a tie rod end 7 in a substantially horizontal plane. Each tie rod 5 is rotatably connected to one relay rod 9 by a tie rod end 11 in a substantially vertical plane. The end of the pitman arm 13 is rotatably connected to one end of the relay rod 9 in a substantially horizontal plane. A rotary shaft 15 is fixed orthogonally to the rear end of the pitman arm 13. An idler arm 17 is rotatably connected to the other end of the relay rod 9 in a substantially horizontal plane. The other end of the idler arm 17 is rotatably attached to the vehicle body.

An actuator unit 19 is provided on the rotary shaft 15 of the pitman arm 13. That is, when the steering force is input by the steering wheel 21, the stub shaft 27 rotates via the column shaft 23 and the intermediate shaft 25. The stub shaft 27 is orthogonally connected to the rotary shaft 15 at the rear end of the pitman arm 13 via a torsion bar 29. When the rotation torque is generated by the steering force, the torsion bar 29 is twisted, and relative rotation is generated between the stub shaft 27 and the rotation shaft 15 of the pitman arm 13. One driven bevel gear 31 is coaxially and rotatably provided on the stub shaft shaft side, and one driven bevel gear 33 is coaxially and relatively rotatably provided on the rotating shaft 15 side of the pitman arm 13. There is. Both driven bevel gears 31 and 33 face each other. One driven bevel gear 35 is always meshed with these driven bevel gears 31 and 33. A rotational driving force is transmitted from the electric motor 41 to the drive bevel gear 35 via the output shaft 37 and the speed reducer 39.

The lower end of the stub shaft 27 and the upper end of the rotating shaft 15 of the pitman arm 13 are respectively cylindrical, and are close to and face each other, and the torsion bar 29 is located inside. A helical spline 43 is formed on the outer periphery of the lower end of the stub shaft 27, and a straight spline 45 is formed on the outer periphery of the upper end of the rotating shaft 15. A select gear 47 is provided across the splines 43 and 45. The select gear 47 has a helical spline 43 formed above the inner peripheral surface and a straight spline 45 formed below the helical spline 43. As a result, when the stub shaft 27 and the rotating shaft 15 rotate relative to each other, the select gear 47 moves upward or downward depending on the direction of the rotation. When moved upward, the upper surface of the select gear 47 contacts the lower surface of the driven bevel gear 31. A clutch shoe 49 is provided at each of the contact portions, and the clutch is engaged by the contact. Further, when the select gear 47 moves downward, the clutch 49 of the other driven bevel gear 33 is similarly engaged by the shoe 49 of another clutch.

In this way, even if the direction of rotation of the drive bevel gear 35 by the electric motor 41 is always a single rotation direction, the select gear 47 moves upward depending on the direction of the rotational torque generated from the steering force by the handle 21. Or you can move down and thus provide power assistance to the right or left. The torque sensor 51 detects the movement of the select gear 47 in the axial direction. That is, the select gear 47 has the protrusion 53 formed on the outer peripheral surface thereof. A torque sensor 51, which is a contact type switch, is provided above and below the protrusion 53, adjacent to the protrusion 53. Then, the select gear 47 moves and the projection 53 presses the switch to turn on the switch. The direction of torque is detected depending on whether the switch is on or off. Alternatively, the magnitude of the torque may be detected by changing the resistance value depending on the magnitude of the pressing force.

The operation of this embodiment will be described below. The steering force from the handle 21 generates a rotation torque, and the torsion bar 29 is twisted, so that relative rotation occurs between the stub shaft 27 and the rotation shaft 15. By this rotation, the select gears 47 move upward or downward by the action of the splines 43 and 45, and the amount of this movement is detected by the torque sensor 51 as the direction of torque and further as a magnitude. Based on this detection, the controller 55 turns on the electric motor 41 or increases the amount of electricity supplied from the power source (battery) 57 to the electric motor. The rotation speed of the electric motor 41 is reduced by the speed reducer 39 and becomes a large force, which is output from the output shaft 37. The output shaft 37 rotates the bevel gears 31, 33 and 35. At this time, due to the movement of the select gear 47, the select gear 47 and the upper or lower bevel gears 31 and 33 are clutched via the shoe 49, and the rotation of the bevel gear 31 or 33 causes the rotation of the rotating shaft 15. Be transmitted to. The rotating shaft 15 causes the pitman arm 13 to rotate in a substantially horizontal plane, and the relay rod 9 connected to the tip end thereof moves rightward or leftward. At the same time, the tie rod 5 also moves to the right or left. As a result, the knuckle arm 3 is pushed or pulled, the direction of the wheel 2 is changed, and steering is performed.

As described above, according to the present embodiment, the actuator unit 19 having the electric motor 41 and the speed reducer 39 is provided at the rear end of the pitman arm 13 constituting the steering link mechanism 1. It is provided for the rotating shaft 15. Therefore, the actuator portion 19 is provided at a position distant from the tie rod 5. That is, the relay rod 9 and the pitman arm 13 are separated from the tie rod 5 by the entire length. Therefore, the size of the vicinity of the tire rod 5 is not increased in the entire electric power steering device. Therefore, the mountability of the device to the vehicle body can be improved as compared with the conventional rack and pinion type electric power steering device.

In the above embodiment, the actuator section 19 is provided on the pitman arm 13 on the side to which the steering force is transmitted, but in other embodiments, two pitman arms are provided, that is, the idler arm 17 is provided. May be provided as a pitman arm, and the steering force from the steering wheel 21 may be transmitted to one pitman arm and the output from the actuator section 19 may be transmitted to the other pitman arm. Further, in the above embodiment, the rotation of the electric motor 41 in one direction can be converted into the rotation in two directions by the upward or downward movement of the select gear 47 and can be transmitted to the steering link mechanism 1. However, in another embodiment, the electric motor 41 can be rotated in two directions. That is, without using the mechanism using bevel gears 31, 33, and 35 as shown in FIG. 2, other torque sensors detect not only the magnitude of the torque but also the direction, and the controller receiving this detection signal detects It is also possible to switch the positive / negative and / or the current amount of the current supplied to the electric motor depending on the direction of the torque.

[0013]

[Effect of device]

 As described above, according to the electric power steering device for a vehicle of the present invention, since the actuator portion is provided near the rear end of the pitman arm, the position far from the tie rod via the relay rod and the pitman arm is increased. The size of the area around the tie rod can be reduced and the mountability on vehicles can be improved. Further, by adopting the steering link mechanism using the pitman arm instead of the rack and pinion type steering gear mechanism, it is not necessary to provide an expensive rack and pinion, and the cost of the device can be reduced.

[Brief description of drawings]

FIG. 1 is an overall front view of an electric power steering apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a part II in FIG.

[Explanation of symbols]

 1 Steering Link Mechanism 2 Wheels 3 Knuckle Arm 5 Tie Rod 7 Tie Rod End 9 Relay Rod 11 Tie Rod End 13 Pitman Arm 15 Rotating Axis 17 Idler Arm 19 Actuator 21 Handle 23 Column Shaft 25 Intermediate Shaft 27 Stub Shaft 29 Torsion Bar 31 Follower Umbrella Gear 33 Driven Bevel Gear 35 Drive Bevel Gear 37 Output Shaft 39 Reducer 41 Electric Motor 43 Helical Spline 45 Straight Spline 47 Select Gear 49 Shu 51 Torque Sensor 53 Projection 55 Controller 57 Power Supply (Battery)

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. An actuator section for detecting a steering force by a torque sensor and power-assisting an electric motor for decelerating a rotation speed of an electric motor and outputting the output from an output shaft. A steering link mechanism in which the front end of the pitman arm is connected to the relay rod, and the rear end serves as a rotation axis for rotation by a steering force, and the output of the actuator section is the rotation axis of the steering link mechanism. Electric power steering device for vehicles etc.