JP6489591B1 - Steering device and traveling vehicle - Google Patents

Abstract

A steering device capable of reducing parts cost and a traveling vehicle provided with the steering device. A steering device (1A) of a steer-by-wire system, comprising: a handle shaft (2), an elastic coupling (3), a brake shaft (4) connected to the handle shaft (2) via an elastic coupling (3); An electromagnetic brake 6 for fixing the brake shaft 4, a control unit for switching on / off the electromagnetic brake 6, and a rotation angle detector 7 for detecting the rotation angle of the handle shaft are provided. The control unit operates the electromagnetic brake 6 when the rotation angle reaches a predetermined limit angle, and releases the electromagnetic brake 6 when the rotation angle is equal to or less than the limit angle. [Selected figure] Figure 1

Description

  The present invention relates to a steering device and a traveling vehicle provided with the steering device.

  A steering apparatus mounted on a traveling vehicle is roughly classified into a system for mechanically transmitting a steering wheel operation of a driver to a steering mechanism and a steer-by-wire system for electrically transmitting the steering wheel operation. The steer-by-wire system can reduce the weight of the vehicle and can increase the degree of freedom in the layout of the steering wheel and the steering mechanism in the vehicle, as compared with the former system.

  As a conventional steering device of a steer-by-wire system, for example, the one described in Patent Document 1 is known. The steering apparatus described in Patent Document 1 includes a handle shaft, a brake shaft, an electromagnetic brake, a control unit that controls the electromagnetic brake, a detector that detects the rotation of the brake shaft, and a detection that detects the rotation of the handle shaft. And the

  In the above-mentioned conventional steering device, the brake shaft is connected to the handle shaft via an elastic coupling. In the above-described conventional steering apparatus, when the driver releases the steering wheel at the steering end, the steering shaft is returned to the neutral position by the restoring force of the elastic coupling, and the electromagnetic brake is released. Thereby, heating of the electromagnetic brake due to the electromagnetic brake continuing to operate can be suppressed.

JP, 2016-16779, A

  However, the above-mentioned conventional steering device has a problem that parts cost increases because it comprises two relatively expensive detectors (a detector for detecting the rotation of the brake shaft and a detector for detecting the rotation of the handle shaft) is there.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a steering device capable of reducing parts cost and a traveling vehicle provided with the steering device.

In order to solve the above-mentioned subject, the steering device concerning the present invention is:
Stair-by-wire steering system,
A handle shaft to which a handle is connected at one end side,
An elastic coupling provided on the other end side of the handle shaft;
A brake shaft whose one end is connected to the handle shaft via the elastic coupling;
A housing for receiving the other end of the handle shaft, the resilient coupling, and the one end of the brake shaft;
An electromagnetic brake that fixes the brake shaft when actuated;
A control unit that switches on / off of the electromagnetic brake;
A rotation angle detector for detecting a rotation angle of the handle shaft;
A bearing provided between the brake shaft and the housing;
And a rotation resistor provided on the other end side of the brake shaft ,
The control unit operates the electromagnetic brake when the rotation angle reaches a predetermined limit angle, and releases the electromagnetic brake when the rotation angle is equal to or less than the limit angle .
The bearing has a bearing portion extending in the axial direction of the brake shaft, and a collar portion provided at one end of the bearing portion.
The brake shaft has a first surface that abuts on a surface on one side of the buttocks,
The housing has a second surface opposite to the first surface across the ridge portion and in contact with the other surface of the ridge portion,
The rotary resistor applies an elastic force in a direction in which the first surface approaches the second surface to the brake shaft .

In the above steering apparatus,
It is preferable that the elastic coupling return the handle shaft to a predetermined neutral position when the rotational operation of the handle is released with the rotational angle reaching the limit angle.

The above steering device
A first gear provided on the handle shaft;
A second gear meshing with the first gear;
The rotation angle detector may be configured to detect a rotation angle of the second gear.

In order to solve the above-mentioned subject, a traveling vehicle concerning the present invention,
A steering apparatus according to any one of the above is provided.

  According to the present invention, it is possible to provide a steering device capable of reducing parts cost and a traveling vehicle provided with the steering device.

It is a figure showing the steering device concerning a 1st embodiment of the present invention. It is a sectional view in the AA 'line of Drawing 1, and (A) is a figure when a steering wheel is in a neutral state, (B) is a figure when rotating a steering wheel 10 degrees to the right, (C) is a steering wheel Is rotated 10 ° to the left. It is a figure which shows the angle detection characteristic of the rotation angle detector which concerns on 1st Embodiment. It is a figure showing the steering device concerning a 2nd embodiment of the present invention.

  Hereinafter, with reference to the attached drawings, embodiments of a steering apparatus according to the present invention and a traveling vehicle provided with the steering apparatus will be described.

First Embodiment
FIG. 1 shows a steer-by-wire steering apparatus 1A according to a first embodiment of the present invention.

  The steering device 1A is provided in a traveling vehicle such as a forklift and a transport vehicle. The traveling vehicle includes a steering wheel operated by a driver, steered wheels, and a steering mechanism that changes the steering angle of the steered wheels. The steering device 1A electrically transmits the rotation operation of the steering wheel by the driver to the steering mechanism.

  The steering device 1A includes a handle shaft 2, an elastic coupling 3, a brake shaft 4, a housing 5, an electromagnetic brake 6, a rotation angle detector 7, and a control unit (not shown). The control unit is, for example, a microcomputer and is provided at a position away from the housing 5.

  The handle shaft 2 is connected to one end side (upper end side). When the driver rotates the steering wheel, the steering wheel shaft 2 rotates with the steering wheel. The brake shaft 4 is connected to the other end side (lower end side) of the handle shaft 2 via an elastic coupling 3. In addition, the handle shaft 2 has a pin 2a protruding toward the other end (see FIG. 2).

  The elastic coupling 3 has an elastic member, and transmits the rotation of the handle shaft 2 to the brake shaft 4 via the elastic member. The elastic coupling 3 has a play of a predetermined angle between the handle shaft 2 and the brake shaft 4.

  Specifically, as shown in FIG. 2A, the elastic coupling 3 has a U-shaped plate spring (elastic member) 3 a and a retaining ring 3 b connected to the handle shaft 2. In the neutral state (the state in which the handle is in the neutral position) shown in FIG. 2A, the pin 2a projecting from the handle shaft 2 is not in contact with the leaf spring 3a.

  When the handle is rotated 10 ° to the right from the neutral state, as shown in FIG. 2B, the handle shaft 2 and the pin 2a are rotated to the right by 10 ° to elastically deform the leaf spring 3a. At this time, the brake shaft 4 is not yet rotated. When the steering wheel is further rotated to the right from the state of FIG. 2B, the brake shaft 4 also rotates to the right together with the steering wheel shaft 2.

  Similarly, when the handle is rotated by 10 ° to the left from the neutral state, as shown in FIG. 2C, the handle shaft 2 and the pin 2a are rotated to the left by 10 ° to elastically deform the leaf spring 3a. At this time, the brake shaft 4 is not yet rotated. When the steering wheel is further rotated to the left from the state shown in FIG. 2C, the brake shaft 4 is also rotated to the left together with the steering wheel shaft 2.

  When the driver cancels the turning operation of the steering wheel while the electromagnetic brake 6 is in operation (when the driver releases the steering wheel), the elastic coupling 3 is moved by the restoring force of the leaf spring 3a (elastic member). The axis 2 is returned to the predetermined neutral position. Further, even when the electromagnetic brake 6 is actuated, when the driver strongly rotates the steering wheel away from the neutral position, the steering wheel and the steering shaft 2 slightly rotate in the direction away from the neutral position. Therefore, the rotational angle detector 7 can detect the rotational direction from the limit angle.

  The elastic coupling 3 is connected to one end side (upper end side) of the brake shaft 4, and the electromagnetic brake 6 is connected to the other end side (lower end side).

  The housing 5 accommodates the other end side of the handle shaft 2, the elastic coupling 3, one end side of the brake shaft 4, and the rotation angle detector 7. An oil seal 8 and a rolling bearing are provided between the housing 5 and the handle shaft 2. A rolling bearing is also provided between the housing 5 and the brake shaft 4.

  The electromagnetic brake 6 is in contact with the lower outer peripheral surface of the housing 5 on the other end side (lower end side) of the brake shaft 4. The electromagnetic brake 6 fixes the brake shaft 4 to be non-rotatable when activated, and releases the brake shaft 4 to be rotatable when released.

  The rotation angle detector 7 detects the rotation angle of the handle shaft 2. The rotation angle detector 7 can use, for example, a two-output potentiometer having an angle detection characteristic shown in FIG. As shown to the same figure, the rotation angle detector 7 outputs the 1st output voltage signal (output 1) and 2nd output voltage signal (output 2) corresponding to detection angle 0 degree-360 degrees to a control part. The first output voltage signal and the second output voltage signal are 180 degrees out of phase.

  The rotation of the handle shaft 2 is transmitted to the rotation angle detector 7 via the first gear 9a and the second gear 9b. The first gear 9 a is provided on the handle shaft 2. The second gear 9 b is provided on an axis different from the handle shaft 2 so as to mesh with the first gear 9 a. The rotation angle detector 7 detects the rotation angle of the handle shaft 2 by detecting the rotation angle of the second gear 9 b.

  The control unit is configured to be able to communicate with the electromagnetic brake 6 and the rotation angle detector 7, and switches the operation / release of the electromagnetic brake 6 based on the detection result of the rotation angle detector 7.

  Specifically, the control unit specifies the rotation angle of the handle shaft 2 based on the first output voltage signal (output 1) and the second output voltage signal (output 2) of the rotation angle detector 7. Then, the control unit compares the limit angle with the rotation angle of the handle shaft 2. When the traveling vehicle has a plurality of traveling modes, the control unit identifies the traveling mode, and then compares the limit angle in the identified traveling mode with the rotation angle of the handle shaft 2.

  For example, when the traveling vehicle is an omnidirectional forklift, the traveling mode includes a normal movement mode, a parallel movement mode, an oblique movement mode, and the like. The limit angle is different for each driving mode. The control unit stores in advance the limit angle corresponding to each traveling mode.

  As a result of comparing the predetermined limit angle with the rotation angle of the handle shaft 2, the control unit operates the electromagnetic brake 6 when the rotation angle reaches the limit angle, and the electromagnetic brake when the rotation angle is less than the limit angle. Do not operate 6 (cancel).

  When the turning operation of the steering wheel by the driver is released (when the driver releases the steering wheel) while the electromagnetic brake 6 is in operation, the steering wheel shaft 2 tends to return to the neutral position by the elastic coupling 3. In the process of returning the steering wheel shaft 2 to the neutral position, the control unit releases the electromagnetic brake 6 because the rotation angle of the steering wheel becomes equal to or less than the limit angle. Therefore, it is possible to suppress the heating of the electromagnetic brake 6 due to the electromagnetic brake 6 continuing to operate, and the driver can operate the steering wheel smoothly.

  In the steering apparatus 1A according to the present embodiment, the control unit is configured to switch the operation / release of the electromagnetic brake 6 based on only the rotation angle of the steering wheel shaft 2. In other words, since the steering device 1A determines the operation / release of the electromagnetic brake 6 based on one detector (rotational angle detector 7), the steering device 1A is compared with a conventional steering device having two detectors. Component costs can be reduced.

Second Embodiment
FIG. 4 shows a steering apparatus 1B according to a second embodiment of the present invention.

  The steering device 1B is provided in a traveling vehicle such as a forklift and a transport vehicle, as in the steering device 1A of the first embodiment. The traveling vehicle includes a steering wheel operated by a driver, steered wheels, and a steering mechanism that changes the steering angle of the steered wheels. The steering device 1B electrically transmits the rotation operation of the steering wheel by the driver to the steering mechanism.

  The steering apparatus 1B is the steering apparatus according to the first embodiment except that the steering apparatus 1B includes the slide bearing 10 and the rotation resistor 20, and that the brake shaft 4 has the first surface 4a and the housing 5 has the second surface 5a. It is common with 1A.

  The slide bearing 10 is provided between the brake shaft 4 and the housing 5. The slide bearing 10 has a cylindrical bearing portion 11 extending in the axial direction of the brake shaft 4 and an annular collar portion 12 provided at one end (upper end) of the bearing portion 11.

  The first surface 4 a of the brake shaft 4 is an annular flat surface that abuts the surface (upper surface) on one side of the heel portion 12. The second surface 5 a of the housing 5 is an annular flat surface opposed to the first surface 4 a with the collar 12 interposed therebetween and in contact with the other surface (lower surface) of the collar 12.

  The rotation resistor 20 includes a connecting shaft portion 21 connected to the brake shaft 4 and an elastic portion 22 that applies a downward elastic force to the connecting shaft portion 21.

  The connecting shaft portion 21 extends in the axial direction of the brake shaft 4, and one end side (upper end side) is connected to the other end side (lower end side) of the brake shaft 4. For example, when the connecting shaft portion 21 is pulled downward, the brake shaft 4 is also pulled downward. At the other end side (lower end side) of the connecting shaft portion 21, a fixing portion 23 for maintaining the elastic portion 22 in a compressed state is provided.

  The elastic portion 22 is, for example, a coil spring provided around the axis of the connecting shaft portion 21. The elastic portion 22 applies an elastic force (a downward elastic force) in the direction in which the first surface 4 a approaches the second surface 5 a to the fixing portion 23 of the connecting shaft portion 21. The elastic force is transmitted to the brake shaft 4 via the connecting shaft portion 21. That is, the elastic portion 22 applies, to the brake shaft 4, an elastic force (a downward elastic force) in the direction in which the first surface 4a approaches the second surface 5a.

  The fixing portion 23 is configured to be movable in the axial direction of the connecting shaft portion 21. By moving the fixing portion 23 upward in the connecting shaft portion 21, the compression state of the elastic portion 22 is strengthened, and the elastic force of the elastic portion 22 is increased. On the other hand, by moving the fixing portion 23 downward in the connecting shaft portion 21, the compression state of the elastic portion 22 is weakened and the elastic force of the elastic portion 22 is reduced.

  When the first surface 4 a of the brake shaft 4 approaches the second surface 5 a of the housing 5 due to the elastic force of the elastic portion 22, the force holding the flange 12 between the first surface 4 a and the second surface 5 a becomes stronger. The friction force generated at the heel 12 during rotation is increased. The frictional force generated at the heel portion 12 is a resistance to the rotation of the brake shaft 4 and a resistance to the rotation of the handle shaft 2 connected to the brake shaft 4 via the elastic coupling 3. Therefore, according to the steering device 1B according to the present embodiment, the rotation of the steering wheel can be resisted, and the feeling of the rotation operation of the steering wheel by the driver can be improved.

  Further, according to the steering apparatus 1B according to the present embodiment, similarly to the steering apparatus 1A of the first embodiment, the determination of the activation / cancellation of the electromagnetic brake 6 is made based on one detector (rotational angle detector 7) As it is done, parts costs can be reduced compared to conventional steering systems with two detectors.

[Modification]
Although the embodiments of the steering apparatus according to the present invention and the traveling vehicle provided with the steering apparatus have been described above, the present invention is not limited to the above embodiments.

  If the rotation angle detector 7 detects the rotation angle of the handle shaft 2, the configuration can be changed as appropriate. That is, any detector other than the two-output potentiometer having the angle detection characteristic shown in FIG. 3 can be used.

  The elastic coupling 3 has an elastic member, and if the rotation of the handle shaft 2 is transmitted to the brake shaft 4 through the elastic member, the configuration can be appropriately changed. For example, although the leaf spring 3a is used as the elastic member in the above embodiment in terms of downsizing and cost reduction, an elastic member other than the leaf spring 3a may be used. Further, it is preferable that the elastic coupling 3 return the steering wheel shaft 2 to a predetermined neutral position by the restoring force of the elastic member when the driver's rotational operation of the steering wheel is released while the electromagnetic brake 6 is in operation. .

  The control unit that switches the operation / release of the electromagnetic brake 6 operates the electromagnetic brake 6 when the rotation angle reaches a predetermined limit angle, and releases the electromagnetic brake 6 when the rotation angle is less than the limit angle The configuration can be changed as appropriate.

  If the slide bearing 10 is a bearing having a bearing portion extending in the axial direction of the brake shaft 4 and a flange portion provided at one end of the bearing portion, the configuration can be appropriately changed.

  The rotational resistor 20 can be appropriately changed in configuration as long as the elastic force in the direction in which the first surface 4 a approaches the second surface 5 a is applied to the brake shaft 4.

1A, 1B Steering device 2 Handle shaft 3 Elastic coupling 4 Brake shaft 5 Housing 6 Electromagnetic brake 7 Rotational angle detector 8 Oil seal 9a First gear 9b Second gear 10 Slide bearing 11 Bearing 12 Flange 12 Rotational resistor 21 Connecting shaft portion 22 Elastic portion 23 Fixing portion

Claims (4)

Stair-by-wire steering system,
A handle shaft to which a handle is connected at one end side,
An elastic coupling provided on the other end side of the handle shaft;
A brake shaft whose one end is connected to the handle shaft via the elastic coupling;
A housing for receiving the other end of the handle shaft, the resilient coupling, and the one end of the brake shaft;
An electromagnetic brake that fixes the brake shaft when actuated;
A control unit that switches on / off of the electromagnetic brake;
A rotation angle detector for detecting a rotation angle of the handle shaft;
A bearing provided between the brake shaft and the housing;
And a rotation resistor provided on the other end side of the brake shaft ,
The control unit operates the electromagnetic brake when the rotation angle reaches a predetermined limit angle, and releases the electromagnetic brake when the rotation angle is equal to or less than the limit angle .
The bearing has a bearing portion extending in the axial direction of the brake shaft, and a collar portion provided at one end of the bearing portion.
The brake shaft has a first surface that abuts on a surface on one side of the buttocks,
The housing has a second surface opposite to the first surface across the ridge portion and in contact with the other surface of the ridge portion,
The steering apparatus , wherein the rotation resistor applies an elastic force in a direction in which the first surface approaches the second surface to the brake shaft . The said elastic coupling returns the said handle shaft to a predetermined | prescribed neutral position, when rotation operation of the said handle is cancelled | released in the state in which the said rotation angle reached the said limit angle. Steering device. A first gear provided on the handle shaft;
A second gear meshing with the first gear;
The rotational angle detector is a steering device according to claim 1 or 2, characterized in that for detecting the rotation angle of the second gear. A traveling vehicle comprising the steering device according to any one of claims 1 to 3 .

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