JPH066165U - Electric power steering actuator - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an electric power steering actuator capable of preventing damage to parts of a propulsion shaft that occur when the propulsion shaft of a steering cylinder is suddenly stopped. [Structure] A steering cylinder provided with a motor 3 driven according to a rotation angle of a steering wheel, and a ball-screw type propulsion shaft 15 for converting the rotational movement transmitted from the motor 3 into a linear movement and transmitting the linear movement to a steering link mechanism. A torque limiter 21 is provided between the first and second terminals. [Effect] When the ball-screw type propulsion shaft 15 is suddenly stopped at the stroke end or the like, the energy of inertial force accompanying the rotation of the motor 3 is absorbed by the torque limiter 21. Therefore, it is possible to prevent damage to parts such as the ball joint and the center arm attached to the ball screw type propulsion shaft 15.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electric power steering actuator including a motor driven according to a rotation angle of a steering wheel and a steering cylinder that converts the rotational motion of the motor into a linear motion and transmits the linear motion to a steering link mechanism. To do.

[0002]

[Prior art]

 In recent years, electric power steering tends to be adopted for energy saving and noise reduction of vehicles.

The structure of a steering employing an electric power steering and the structure of a conventional electric power steering actuator will be described with reference to FIGS. 2 and 3. In FIG. 2, reference numeral 1 denotes an electric power steering actuator, which drives a motor 3 driven in accordance with the rotation angle of the steering wheel 2 and the rotational movement of the motor 3 as shown in FIG. It is composed of a steering cylinder 5 which is connected to an output shaft 11 by a connector 12 and which is transmitted to a ball screw type propulsion shaft 15 via a pinion 13 and a gear 14 to be converted into a linear motion and transmitted to a steering link mechanism 4. There is. The drive signal to the motor 3 is output from the power controller 7 according to the rotation angle of the steering wheel 2 detected by the rotation angle sensor 6, and the rotation of the steering wheel 2 is controlled by the steering gear 9 provided in the steering column 8. Is transmitted to the steering link mechanism 4 via. In FIG. 3, 16 is a ball bearing, 17 is a tapered roller bearing, and 18 is a universal joint.

[0004]

[Problems to be solved by the device]

 However, in the configuration of the conventional electric power steering actuator 1 described above, when the ball screw type propulsion shaft 15 is suddenly stopped at the stroke end or the like, unlike the thrust characteristics of the hydraulic power steering actuator shown in FIG. As shown in FIG. 5, an excessive output indicated by an arrow A is generated on the propulsion shaft 15 in response to the inertial force caused by the rotation of the motor 3, and the ball output and the center mounted on the propulsion shaft 15 are accompanied by the excessive output. There was a problem that parts such as the arm might be damaged.

The present invention solves the above problems, and provides an electric power steering actuator that prevents damage to the parts of the propulsion shaft that occur when the propulsion shaft of the steering cylinder is suddenly stopped. It is intended.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, an electric power steering actuator of the present invention is a motor driven according to a rotation angle of a steering wheel, and a rotary motion transmitted from the motor is converted into a linear motion and transmitted to a steering link mechanism. An electric power steering actuator comprising a steering cylinder having a ball screw type propulsion shaft, wherein a torque limiter is provided on the output shaft of the motor, and the driving force of the motor is passed through the torque limiter to the steering cylinder. It is characterized by transmitting to.

[0007]

[Action]

 According to the configuration of the present invention described above, when the ball-screw type propulsion shaft is suddenly stopped, the energy of inertial force accompanying the rotation of the motor is absorbed by the torque limiter. Therefore, damage to the parts of the steering cylinder is prevented.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. It should be noted that the same components as those of the conventional example shown in FIG.

FIG. 1 is a partial cross-sectional side view of an electric power steering actuator according to an embodiment of the present invention. In FIG. 1, 21 is a torque limiter interposed between the output shaft 11 of the motor 3 and the rotating shaft of the pinion 13 of the steering cylinder 5.

The torque limiter 21 has a first gear 22 fitted onto the output shaft 11 of the motor 3 and rotated by the rotation of the motor 3, a flange 23 at one end, and a pinion 13 at the other end. Output shaft 24 connected to the rotating shaft of the connecting member 12 by a connecting member 12, a ring-shaped second gear 25 that rotates around the output shaft 24, a first gear 22 and a second gear 25. A double chain 26 that is mounted across the space and that transmits the rotational force of the first gear 22 to the second gear 25, and ring-shaped first and second brackets that slide around the output shaft 24. 27, 28, a flange 23 of the output shaft 24 between the second gear 25, and a second gear 25 and a bracket 27, respectively, which are ring-shaped first and sliding around the output shaft 24. It is provided between the second friction plates 29 and 30, and between the first bracket 27 and the second bracket 28. Friction plate 30, a second gear 25, and a spring 31 for pressing the flange portion 23 of the output shaft 24 of the first friction plate 29.

Due to the configuration of the torque limiter 21, the driving force of the motor 3 is generated by the output shaft 11 of the motor 3, the first gear 22, the double chain 26, the second gear 25, the first friction plate 29, and the output shaft. The ball screw type propulsion shaft 15 is driven by being transmitted to the pinion 13 of the steering cylinder 5 via the flange portion 23 of 24 and the output shaft 24 in order.

Further, by interposing the torque limiter 21 in this way, when the ball screw type propulsion shaft 15 is suddenly stopped at the stroke end or the like, the energy of inertial force accompanying the rotation of the motor 3 is equal to the torque. It is absorbed by the limiter 21, especially the friction plate 28. Therefore, it is possible to prevent generation of excessive output as in the conventional case, and prevent damage to parts such as the ball joit and the center arm attached to the ball screw type propulsion shaft 15.

[0013]

[Effect of device]

 According to the present invention configured as described above, when the ball screw type propulsion shaft is suddenly stopped at the stroke end or the like, the energy of the inertial force caused by the rotation of the motor can be absorbed by the torque limiter. It is possible to prevent damage to the parts of the propulsion shaft.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view of an electric power steering actuator according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a steering employing an electric power steering.

FIG. 3 is a partial cross-sectional side view of a conventional electric power steering actuator.

FIG. 4 is a thrust characteristic diagram at the stroke end of the hydraulic power steering actuator.

FIG. 5 is a thrust characteristic diagram at a stroke end of a conventional electric power steering actuator.

[Explanation of symbols]

 1 Electric Power Steering Actuator 2 Steering Wheel 3 Motor 4 Steering Link Mechanism 5 Steering Cylinder 11 Motor Output Shaft 12 Connecting Material 13 Pinion 14 Gear 15 Ball Screw Propulsion Shaft 21 Torque Limiter 22 First Gear 23 Flange 24 Torque Output shaft of limiter 25 Second gear 26 Double chain 27, 28 Bracket 29, 30 Friction plate 31 Spring

Claims (1)

[Scope of utility model registration request] 1. A steering cylinder comprising a motor driven according to a rotation angle of a steering wheel, and a ball screw type propulsion shaft for converting a rotational movement transmitted from the motor into a linear movement and transmitting the linear movement to a steering link mechanism. An electric power steering actuator, comprising: a torque limiter provided on an output shaft of the motor, and transmitting a driving force of the motor to the steering cylinder via the torque limiter. .