JPH044175Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a steering rotation detection device that detects the steering end and steering angle of a steering device.

(Prior Art) Generally, in a rack and pinion type steering device, a steering rack is slidably housed in a steering box, and a steering pinion connected to a steering wheel meshes with this steering rack. . Also,
The steering rack is supported by a rack guide so as to be slidable in the axial direction, and the back surface of the rack guide is provided with a screw hole for adjusting the pressing force of the rack guide and a plug body screwed into the screw hole. Such a steering device has a structure in which the steering wheel cannot be steered at the left and right end portions of the steering rack.

(Problems to be Solved by the Invention) However, in the electric power steering device previously filed by the applicant of the present application, it is unnecessary for the electric motor to generate auxiliary torque at the steering end. In addition to wasting power, there is a risk that the electric motor etc. will be overloaded and the durability will be reduced.

(Purpose of the invention) Therefore, the present invention detects the steering end part and the steering angle in an electric power steering device so that the auxiliary torque of the electric motor can be reduced or the electric motor can be controlled to stop driving at the steering end part. An object of the present invention is to provide a steering rotation detection device.

(Means for solving the problem and its effects) An insertion hole for supporting the rack guide is formed in the rack guide that slidably supports the steering rack, and a plug is screwed into the threaded portion of this insertion hole. is blocked. Further, a through hole is formed in the rack guide, and the tip of a rod that slides into contact with the steering rack is disposed through the through hole, and an identification portion is formed on the steering rack to enable identification of its sliding position. Detection means for detecting the identification portion via the rod is provided.

With the above configuration, the detection means detects the identification portion formed in accordance with the position of the steering rack in the sliding direction, such as unevenness or potential gradient, through the rod that slides into contact with the steering rack, so that the steering The stroke amount of the rack, that is, the steering angle can be detected.

(Embodiment) A preferred embodiment of the present invention will be described below based on the accompanying drawings. In this embodiment, an example in which the present invention is applied to an electric power steering device will be described.

As shown in FIG. 1, the electric power steering device includes a steering force booster 1 equipped with an electric motor installed on a steering shaft 2, and an on-vehicle control device 3 that generates an auxiliary torque corresponding to the steering torque. The electric motor is controlled accordingly.

Further, as shown in FIG. 2, a steering rack 5 is housed in the housing 4 of the steering gear box so as to be slidable in the axial direction, and a rack groove is formed on the upper surface of the steering rack 5.
A steering pinion connected to the steering shaft 2 meshes with this rack groove. Further, the steering rack 5 is slidably supported by a rack guide 6 at its lower part. The rack guide 6 has its base end inserted into an insertion hole 7 provided in the housing 4. Further, the opening of the insertion hole 7 is provided with a threaded portion, a plug 8 is screwed onto the threaded portion, and a spring 9 is interposed between the plug 8 and the base end of the rack guide 6. As a result, the rack guide 6 is supported by the housing 4. Therefore, the pushing force of the rack guide 6 is adjusted by the stopper 8, and the steering rack 5 can be engaged with the steering pinion with a required preload applied thereto.

Furthermore, a through hole 10 is provided on the bottom surface of the rack guide 6.
is formed, and a screw hole 1 is concentrically formed with this through hole 10.
1 is formed on the plug body 8. A stroke switch 12 is installed as means for detecting the stopper 8. This stroke switch 12 has a plug body 8.
The case 13 has a threaded portion on its outer periphery to be screwed into the screw hole 11 of the rack guide 6, and the proximal end is slidably inserted into the case 13, and the distal end passes through the through hole 10 of the rack guide 6 and is attached to the lower surface of the steering rack 5. The rod 14 is formed into a spherical shape so as to be in sliding contact with the rod 14. Further, a spring (not shown) is interposed between the rod 14 and the case 13, and the case 1
3 is provided with contacts (not shown) that are switched as the rod 14 moves in the axial direction, and terminals 15a and 15b connected to these contacts are provided at the base end of the case. Further, on the lower surface of the steering rack 5, recesses 16 are provided as identification portions at positions on both sides corresponding to the rack ends. Therefore, when the steering rack 5 reaches the stroke end shown in FIG. can be switched. In this embodiment, the stroke switch 12 and the recess 16 constitute a steering rotation detection device, and 17 in FIGS. 3a and 3b indicates a steering pinion.

On the other hand, in an electric power steering device, an input shaft connected to a steering wheel and an output shaft connected to a steering gear box are arranged coaxially with each other, and the inner ends of the input shaft and output shaft are loosely penetrated. and are connected by a torsion bar. In addition, a steering rotation sensor is installed around the input shaft, a steering torque sensor is installed around the fitting part of the input/output shaft, and an electric motor, speed reduction device, etc. are installed around the output shaft to drive and control the electric motor. It is equipped with a control device to As shown in FIG. 4, this control device includes a steering torque detection means 21, a steering rotation detection means 22, an armature current detection means 23, an electric motor rotation speed detection means 24, and an amplifier 25 for amplifying each of these detection signals. , an A/D converter 26 that converts into a digital signal, a microcomputer 27 that performs arithmetic processing based on this digital signal and outputs a control signal, and a motor drive means 28 that drives an electric motor 29 based on this control signal. The electric motor 29 is driven and controlled by the electric motor driving means 28 based on the control signal from the microcomputer 27, and as a result, an auxiliary torque corresponding to the steering torque is applied to the output shaft.

Furthermore, a switching circuit 31 consisting of the aforementioned stroke switch 12 and relay 30 is interposed between the motor drive means 28 and a power supply circuit that supplies power thereto. This switching circuit 31 is constructed using a stroke switch 12 and a relay 30, both of which are normally open types.As shown in FIG. connected in series. Therefore, in the stroke range of the steering rack 5, the stroke switch 12 and the relay 30 are both closed, and power is supplied to the motor drive means 28.
An auxiliary torque corresponding to the steering torque is applied to the output shaft. On the other hand, at the stroke end portion where the rod tip of the stroke switch 12 engages with the recess 16 of the steering rack 5, the rod 14
As a result of the displacement, the stroke switch 12 is opened, and the relay 30 is also opened accordingly, so that the supply of power to the motor drive means 28 is stopped and no auxiliary torque is applied to the output shaft. As a result, even when the steering wheel is turned and held at the steering end portion, unnecessary power consumption of the electric motor 29 can be reduced, and the risk of the electric motor 29 becoming overloaded can also be prevented.

Further, the switching circuit 31 can be configured in various ways by combining different types of stroke switches and relays.

Although the case where a relay is used as the switching circuit has been described, the present invention is not limited to this, and a semiconductor element such as a transistor may be used instead of the relay.

Next, another embodiment of the present invention will be described.

In this embodiment, the steering rotation detection device is constituted by a variable resistor 32 whose resistance value changes in accordance with the amount of movement of the steering rack 5, as shown in FIG. 5b. For example, the rod 14 of the stroke switch 12 can be configured as a variable contact, and the steering rack 5 can be configured as an identification section using a resistor. Therefore, a voltage corresponding to the stroke amount (travel amount) of the steering rack 5 is taken out from one end of the rod 14 and the steering rack 5, and this voltage value can be used to control the auxiliary torque. For example, if the steering rotation detection device of this embodiment is arranged in block B shown in FIG. By setting 27, the analog voltage corresponding to the stroke amount of the steering rack 5 is applied to the A/D converter 2.
6, it is converted into a digital signal, and based on this digital signal, the microcomputer 27
As a result, control can be performed to reach the steering end portion from the vicinity of the stroke end portion of the steering rack 5, and to reduce the auxiliary torque in proportion to the stroke amount. As a result, when the steering wheel is steered beyond a predetermined amount, the steering force gradually increases, allowing the operator to recognize that the stroke end has been approached.
As the auxiliary torque decreases, the load decreases, making it possible to prevent overload of the electric motor.

(Effect of the invention) As is clear from the above explanation, according to the invention,
The stroke end or stroke amount of the steering rack can be easily detected, and the rack guide and the plug that supports it can be used, so there is no risk of problems such as increased installation space, and the conventional steering gear box can be fully utilized. can do.

[Brief explanation of the drawing]

1 to 5a relate to one embodiment of the present invention, in which FIG. 1 is a perspective view showing a steering device, FIG. 2 is an enlarged sectional view of essential parts showing a rack guide, and FIG.
Figures a and b are explanatory diagrams of the operation of the stroke switch, Figure 4 is a circuit configuration diagram showing the control device of the electric power steering device, Figure 5 a is a circuit diagram showing the switching circuit, and Figure 5 b is another implementation. FIG. 2 is a circuit diagram showing a variable resistor according to an example. In the drawing, 4 is a housing of the steering gear box, 5 is a steering rack, 6 is a rack guide, 7 and 8 are insertion holes and plugs, 10 is a through hole, 12 is a detection means, 14 is a rod, and 16 is an identification part. .

Claims (1)

[Scope of utility model registration request] A steering rack slidably housed in a housing of a steering gear box, a steering pinion meshing with the steering rack and connected to the steering wheel, a rack guide slidably supporting the steering rack, and the rack guide. In a rack and pinion type steering device having an insertion hole provided in the housing for support and a stopper for closing the insertion hole, the tip portion passes through the through hole provided in the rack guide and slides into contact with the steering rack. Steering rotation detection characterized by comprising a rod, an identification part formed on the steering rack to identify the sliding position of the steering rack, and a detection means for detecting the identification part of the steering rack via the rod. Device.