JP4518633B2 - Rotary encoder structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a rotary encoder that is mounted on an automobile or the like and detects a steering angle. When a bearing coupled to a shaft of the rotary encoder causes a grease break or the like, the rotary encoder causes a rotation lock phenomenon. Also relates to the structure of a rotary encoder that enables steering.
[0002]
[Prior art]
Conventionally, this type of rotary encoder has a structure shown in FIG. The rotary encoder in the technology is disposed, for example, near the floor portion of the driver's feet in the driver's seat or in the vicinity of the dash panel, and is used as a component of an automobile driving support system. This automobile driving support system is a device in which a motor drives a steering shaft even when a driver releases his / her hand from a steering wheel during automatic driving of the automobile.
[0003]
As the automobile driving support system, for example, an automatic driving control device disclosed in Japanese Patent Laid-Open No. 10-31799 is known. As shown in FIG. 6, the rotary encoder is mounted on the vehicle body C of the automobile, and the steering actuator 27 is controlled by the operation of the rotary encoder. That is, the vehicle body C is equipped with, for example, a CCD camera 28 that detects a white line on the road, and a white line signal extracted by the image processing ECU 29 from an image captured by the CCD camera 28 is supplied to the vehicle control CO 30 and is then supplied to the road. This is a technology that automatically controls the steering wheel of a car based on the white line above.
[0004]
In FIG. 5, reference numeral 1 denotes one housing, 2 denotes the other housing, and the one and other housings 1 and 2 are combined to form a box-shaped housing 3. A shaft 4 is interposed in the housing 3, and one end of the shaft 4 is connected to a steering shaft and a motor via a worm gear. A sensor board 5 is fixed to the other end of the shaft 4.
[0005]
Further, a steering angle sensor 6 is disposed in the housing 3, and an output signal is derived by detecting the rotational position of the steering wheel by rotating the sensor board 5.
[0006]
[Problems to be solved by the invention]
The structure of the rotary encoder in the prior art has the above-described configuration and has the following problems.
[0007]
When the bearing connected to the shaft of the rotary encoder causes a grease breakage, when a foreign object is mixed in the housing, or when the housing is destroyed, the shaft 4 and the sensor board 5 cannot be rotated. As a result, steering by the steering wheel may be difficult.
[0008]
[Means for Solving the Problems]
The structure of the rotary encoder according to the present invention is to solve the above-mentioned conventional problems, and a part to be broken is provided with a part to be broken that is separated and cut off by an input from the steering shaft. An object of the present invention is to prevent the steering shaft from being locked by dividing the shaft by an input from the steering shaft. The following configuration and means were adopted.
[0009]
According to the first aspect of the present invention, the structure includes a steering angle sensor, a sensor board that controls the operation of the steering angle sensor, and a shaft that fixes the sensor board and interlocks with the steering shaft. A part of the rotary encoder is provided with a portion to be broken that is separated and cut by input from the steering shaft.
[0010]
According to a second aspect of the present invention, there is provided a rotary encoder according to the first aspect, wherein a portion to be broken is formed by a groove having a substantially V-shaped or rectangular cross section extending in the circumferential direction at a substantially intermediate portion of the shaft. Structure.
[0011]
According to a third aspect of the present invention, the shaft has a hollow outer cylinder and at least one protruding protrusion formed on the outer peripheral portion, and the protruding protrusion is engaged with the outer cylinder inner wall. The rotary encoder structure according to claim 1, wherein the projecting part is a part to be destroyed.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the structure of a rotary encoder according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a vertical sectional view showing the structure of a rotary encoder according to the present invention. Reference numeral 7 denotes a housing, and one housing 8 and the other housing 9 are combined to form a set of housings. A shaft 10 and a steering angle sensor 11 are disposed in the housing 7. The shaft 10 is formed in a columnar shape, and a space 12 is formed in a substantially axial core portion. That is, the space 12 includes a large space 12a and a small space 12b that are formed in a series of steps. Destructed by thinly forming a thick portion between the space 12b and the outer peripheral portion at a substantially intermediate position of the shaft 10, that is, between a bearing 14 supporting portion and a coupling portion between gear shafts 20 and 21, which will be described later. Part 13 has, for example, a V-shaped groove as shown.
[0013]
A bearing 14 supports the other end of the shaft 10. The sensor board 16 is attached to the other end of the shaft 10 by a stop spring 17.
[0014]
Next, based on FIG. 2, an embodiment when the rotary encoder according to the present invention is coupled to a steering shaft or a motor of an automobile will be described. FIG. 2 is an overall plan view showing a cross section of the main part. Reference numeral 18 denotes a steering shaft that rotates in conjunction with a steering wheel (not shown). The outer periphery of the steering shaft 18 forms a gear portion and meshes with the gear portion 19 a of the worm gear 19. The worm gear 19 is provided with gear shafts 20 and 21 on the left and right. The gear shaft 20 is connected to a motor 23 via a bearing 22, and the gear shaft 21 is connected to a space 12a of the shaft 10 of the rotary encoder via a bearing 24. It is inserted in and joined.
[0015]
The operation of the first embodiment of the structure of the rotary encoder according to the present invention will be described. When driving a car, the driver rotates the steering wheel. The steering shaft 18 is interlocked with the rotation of the steering wheel. Thus, the gear portion 18a of the steering shaft 18 is meshed with the gear portion 19a of the worm gear 19, and the gear shafts 20 and 21 are rotated. The shaft 10 also rotates, the sensor board 16 rotates, the steering angle sensor 11 operates, and an output signal is derived. Thus, the rotary encoder operates to detect the rotational position of the steering wheel.
[0016]
In addition, when the automatic travel control device is operated, even if the driver releases his hand from the steering wheel, the motor 23 rotates and is transmitted to the worm gear 19 via the gear shafts 20 and 21, thereby operating the rotary encoder and steering. An axis control unit (not shown) is operated to control the rotation of the steering shaft 18.
[0017]
Next, when there is grease breakage of the bearing 14 coupled to the shaft 10 of the rotary encoder, or when foreign matter is mixed in the housing 7 or the housing 7 is destroyed, the gear shaft is operated by operating the steering wheel. In order to prevent the steering shaft from being locked, an external force is applied to 20, 21 and the shaft 10 is twisted and stress is concentrated at the bottom of the V-shaped groove 13 to cause cracks. did.
[0018]
If the shaft 10 is divided even by the driving torque of the motor 23 constituting the actuator of the automatic travel device, the motor 23 can continue traveling even if a malfunction occurs in the rotary encoder during automatic travel. Can do.
[0019]
FIG. 3 is a sectional view showing a first modification of the shaft 10 of the rotary encoder according to the present invention. If this is demonstrated, the to-be-destructed part 133 formed in the substantially intermediate part of the shaft 10 is comprised by the rectangular groove | channel. The operation of dividing the shaft 10 is performed in the same manner as in the first modification described above, with cracks K5 and K6 occurring in the fractured part 133. Thus, the steering shaft lock phenomenon was prevented. Further, since the other components are the same as those in FIG. As described above, the parts to be destroyed 13 and 133 formed at substantially the intermediate part of the shaft 10 are not limited to the above-described embodiment, and other modifications may of course be used.
[0020]
FIG. 4 is a sectional view showing a second modification of the rotary encoder according to the present invention. To describe this, the shaft 100 is formed in a hollow cylinder, and an outer cylinder 110 having a space 120, and an inner body 130 in which overhanging protrusions 131 and 132 fitted in the space 120 are formed on the top. Consists of. The overhanging protrusions 131 and 132 are two flat plate members projecting in the diameter direction from the axial center of the inner body 130, and the tips are embedded and engaged with the inner wall 111 constituting the space 120 of the outer cylindrical body 110. The central portion of the inner body 130 forms a hollow portion 133 ′. In this second modification, first, the inner body 130 is molded, and the inner body 130 is integrated in the outer cylinder 110 by positioning and molding the outer cylinder 110 so-called two-color molding or two-color molding. Constructed by heavy molding. The other components are the same as in FIG. Therefore, when an excessive external force is applied to the gear shafts 20 and 21, cracks K3 and K4 are generated in the protruding protrusions 131 and 132 of the inner body 130, and the coupling between the outer cylinder 110 and the inner body 130 is broken. . And it tried to prevent the lock phenomenon of the handle shaft. 4A is a vertical cross-sectional view of the shaft 110, and FIG. 4B is a cross-sectional view in the direction of the arrow AA in FIG. 4A.
[0021]
【The invention's effect】
The structure of the rotary encoder according to the present invention has the following effects because it has the above-described configuration and operation.
According to the first aspect of the present invention, the structure includes a steering angle sensor, a sensor board that controls the operation of the steering angle sensor, and a shaft that fixes the sensor board and interlocks with the steering shaft. A part of the rotary encoder is provided with a portion to be broken that is separated and cut by input from the steering shaft. With this configuration, even when there is grease breakage in the bearing, foreign matter is mixed in the housing, or the housing is destroyed, the steering shaft lock phenomenon is prevented, and the steering wheel of the automobile is prevented. Operation can be performed smoothly. Further, if the part to be broken is separated and cut even by the torque of the motor, it can be applied to an automatic traveling control device, and the fail-safe function can be enhanced and the safety of the automobile can be enhanced.
[0022]
According to a second aspect of the present invention, there is provided a rotary encoder according to the first aspect, wherein a portion to be broken is formed by a groove having a substantially V-shaped or rectangular cross section extending in the circumferential direction at a substantially intermediate portion of the shaft. Structure. As described above, since the portion to be broken having a predetermined cross-sectional shape is formed in the substantially middle portion of the shaft, the structure is simple, and it is not necessary to provide a different member to be broken and can be produced very easily. At the same time, even when an accident such as a bearing occurs, the shaft can be quickly divided to prevent the steering shaft from being locked.
[0023]
According to a third aspect of the present invention, the shaft has a hollow outer cylinder and at least one protruding protrusion formed on the outer peripheral portion, and the protruding protrusion is engaged with the outer cylinder inner wall. The rotary encoder structure according to claim 1, wherein the projecting part is a part to be destroyed. Since such a configuration is adopted, since the overhanging protrusion of the member to be broken connected to the motor shaft is locked to the hollow inner wall of the shaft, the overhanging protrusion even when an accident such as a bearing occurs Is cut off and separated from the gear shaft, the steering shaft locking phenomenon can be prevented.
[Brief description of the drawings]
FIG. 1 is a vertical sectional view showing Embodiment 1 in the structure of a rotary encoder according to the present invention.
FIG. 2 is an overall plan view showing a cross section of a main part showing a state when the structure of the rotary encoder according to the present invention is mounted around a handle shaft of an automobile.
FIG. 3 is a cross-sectional view showing a first modification of the shaft mounted on the rotary encoder according to the present invention.
FIG. 4 is a cross-sectional view showing a second modification of the shaft attached to the rotary encoder according to the present invention.
FIG. 5 is a vertical sectional view showing a structure of a rotary encoder in the prior art.
FIG. 6 is a perspective view of an automobile equipped with an automatic travel control device according to a conventional technique.
[Explanation of symbols]
7 Housing 8 One housing 9 Other housing 10 Shaft 111 Inner wall 11 Rudder angle sensors 12, 12a, 12b Space 13, 133 Destroyed portion 14 Bearing 16 Sensor board 17 Stop spring 18 Steering shaft 18a Gear shaft 19 Worm gear 19a Gear portion 20 , 21 Gear shaft 22 Bearing 23 Motor 131, 132 Overhang protrusion 133 Hollow part 110 Outer cylinder 130 Inner body K1-K6 Crack

Claims (3)

A steering angle sensor, a sensor board that controls the operation of the steering angle sensor, and a shaft that fixes the sensor board and interlocks with a steering shaft, the input from the steering shaft being part of the shaft A structure of a rotary encoder, characterized in that a portion to be broken is provided that is separated and cut at a point. 2. The structure of a rotary encoder according to claim 1, wherein a portion to be broken is formed by a groove extending in a circumferential direction having a substantially V-shaped cross section or a rectangle in a substantially middle portion of the shaft. The shaft is composed of a hollow outer cylindrical body and an inner body in which at least one protruding protrusion is formed on the outer peripheral portion and the protruding protrusion is locked to the outer cylindrical body wall, 2. The structure of a rotary encoder according to claim 1, wherein the projecting protrusion is used as a part to be broken.

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