JP2000211485A - Assist device of parking brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an assist device of a parking brake smooth in operation even in the case of a manual operation, capable of obtaining sufficient assist force even in the middle of an operation and at the end of the operation and high in mechanical efficiency. SOLUTION: This assist device A is provided with a transmission lever 17 which is freely rotatably supported in the vicinity of an intermediate position, an operating cable 20 which is freely rotatably connected to one end of the transmission lever 17 and connects the transmission lever 17 and a brake operating lever 25, a driven cable 21 which is freely rotatably connected to the other end of the transmission lever 17 and connects the transmission lever 17 and a center brake 27 for parking and a motor M with a reduction gear G for rotating and driving the transmission lever 17. In this case, an electromagnetic clutch 9 capable of selecting a state that a torque transmission from the motor M side to the transmission lever 17 side is made possible and a state that torque transmission from the transmission lever 17 side to an actuator side is made impossible is provided between the reduction gear G and the transmission lever 17 side. On each of the operating cable 20 and the driven cable 21, pulling force sensors 26, 28 for controlling motor M are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a parking brake assist device. More specifically, the present invention relates to an assist device suitably used for a center brake (center parking brake) of an automobile, particularly a large automobile such as a truck or a trailer.

[0002]

2. Description of the Related Art In large vehicles such as trucks, a center brake for mechanically restraining rotation of a drive shaft by a friction plate is provided behind a transmission as a parking brake. Such a center brake mechanically connects the brake operation lever provided in the driver's seat and the brake lever of the center brake with a cable, pulls up the operation lever to pull the cable, rotates the brake lever, It works. Further, the operation lever is provided with a ratchet mechanism for preventing reverse movement, and the ratchet is released by a push button or the like provided at the upper end of the operation lever for releasing the ratchet.

Such a parking brake requires a strong braking force especially in a large truck or the like, and thus requires a large force at the end of the stroke of the operating lever. In order to solve this problem, for example, it is conceivable to increase the lever ratio of the operation lever, but in that case, the rotation stroke of the operation lever becomes large, and the operation becomes rather difficult.

On the other hand, as an assist device for a parking brake of a normal automobile, for example, Japanese Utility Model Publication No. 6-2848
Is described in Japanese Patent Application Publication No. This is shown in FIG.
As shown in FIG.
And a cable 104 connected to a motor-driven actuator 103 are arranged in parallel, and these ends are connected to both ends of a balance lever 105. The center of the balance lever 105 is rotatably connected to a connecting member 106, connected to two driven cables 108 by an equalizer 107, and connected to a brake lever of a wheel 109a.

Further, the inclination of the connecting member 106 is detected by a relative displacement detection switch 109, and the operation of the actuator 103 is made to follow the operation amount of the operation lever 101. Reference numeral 110 is a control circuit. Further, for fail-safe, a stopper for restricting the angle of the balance lever 105 to a predetermined angle or less is provided so that the balance lever 105 can be pulled and operated only by the operation lever 101, and the stopper is provided so as not to obstruct the cable 103 on the actuator side. The head 104 a of the cable 104 is made to come out of the engagement hole 105 a of the balance lever 105.

[0006] Japanese Patent Application Laid-Open No. 6-48290 discloses that
Basically, it is manually operated, and the operation state of the parking brake is detected by detecting the operation state of the parking brake with a reaction force switch and a reaction force detector and increasing the tension of the operation cable only when the brake state is not sufficient. An apparatus is disclosed. Further, in JP-A-6-144221, a divided reel is provided around a drive boss, and a midway of a brake operation cable is wound around the reel,
A power assist device using a kind of friction clutch is disclosed in which when a certain amount of tension is applied to a brake operation cable, torque is transmitted to the reel by friction between the reel and the drive boss.

[0007]

SUMMARY OF THE INVENTION
In the power assist device disclosed in JP-A-48-48, since the operating cable 102 and the connecting member 106 are eccentrically arranged, the connecting member cannot be moved smoothly in the case of manual operation. Also, when the connecting member 106 is operated by the actuator 103, the movement is not smooth due to the eccentricity. Further, the actuator 103 operates only when the relative displacement (difference in the amount of movement) between the cable 102 on the operation lever side and the cable 104 on the actuator side is equal to or greater than a predetermined value. Become. Moreover, the balance lever 105
There are some dead zones when detecting the inclination of
There is a case where the operating force cannot be sufficiently reduced at the final stage of the operation requiring the most operating force. Therefore, it is not appropriate to adopt it for center parking of trucks and the like.

The operating device disclosed in Japanese Patent Application Laid-Open No. 6-48290 can compensate for the braking force when the final braking state is insufficient, but cannot assist the operating force during operation. Japanese Patent Application Laid-Open No. 6-14421
The assist device disclosed in Japanese Patent Publication No. 1 has an advantage that a torque transmission force is generated in a friction clutch by a manual operation force.
Efficiency is low because the friction part has slippage.

According to the present invention, parking can be performed smoothly even in the case of manual operation, a sufficient assisting force can be obtained during the operation and at the end of the operation, the mechanical efficiency is high, and the parking can be suitably used for a center brake of a truck. The technical problem is to provide a brake assist device.
A further object of the present invention is to provide an assist device that can easily switch between a manual operation and a power assist operation, and that can also respond to an operation using only an electric operation.

[0010]

A parking brake assist device according to the present invention includes a transmission lever rotatably supported in the vicinity of an intermediate portion, and a transmission lever rotatably connected to one end of the transmission lever. An operation cable connecting between the brake operation lever, a driven cable rotatably connected to the other end of the transmission lever and connecting between the transmission lever and the parking brake, and an operation cable for rotating the transmission lever. And an actuator.

In such an assist device, between the actuator side and the transmission lever side, a state in which torque can be transmitted from the actuator side to the transmission lever side and a state in which torque transmission from the transmission lever side to the actuator side is disabled. Preferably, a selectable clutch mechanism is provided. Further, a pulling force sensor is provided for each of the operation cable and the driven cable, and when the pulling force sensor of the operating cable detects a predetermined or more pulling force, the actuator is rotated in the pulling direction of the driven cable, and the pulling force sensor of the driven cable is It is preferable to provide a control circuit for stopping the actuator when a predetermined or more pulling force is detected.

The clutch mechanism may be an electromagnetic clutch that turns on and off torque transmission between the actuator side and the transmission lever side. Further, when viewed from the actuator side, a torque can be transmitted to the transmission lever side when the transmission lever is rotated in a direction in which the driven cable is pulled, and a one-way clutch that is free in the opposite direction can be used.
Further, the transmission lever may be provided with an arc-shaped tooth row centered on the rotation center, and the pinion driven by the actuator may be meshed with the tooth row.

A supporting member for rotatably supporting the transmission lever is provided movably in a direction substantially parallel to a moving direction of the cable, and the actuator drives the supporting member in a pulling direction of the cable. Thus, the transmission lever can be configured to rotate about the connecting portion of the operation cable.

In this case, the support member may be a support lever having a center of rotation on a side opposite to the support portion with the connecting portion between the transmission lever and the operation cable interposed therebetween, and the actuator may be driven to rotate the support lever. It is preferable to configure. Further, a drive lever driven by the actuator and a connection lever connecting the drive lever and the support lever are provided, and the drive lever, the connection lever, and the support lever rotate in a direction in which the drive lever pulls the driven cable. It is preferable to configure the toggle mechanism so that the angle between the drive lever and the connection lever is close to a straight line when moved.

[0015]

According to the assist device of the present invention, in the case of manual operation,
Since the operation cable and the driven cable are connected to both ends of the transmission lever, when the operation cable is pulled, the transmission lever rotates, whereby the driven cable can be pulled.
When the pulling force of the operation cable is reduced, the operation cable can be sent out by the return force of the driven cable. As described above, in the device of the present invention, since the operation cable and the driven cable are substantially connected via the transmission lever,
The movement is smoother than in the case of the eccentric connection, and the mechanical efficiency is higher than the torque transmission using friction.

In the case of the assist operation, when the actuator drives the transmission lever to rotate, the driven cable is pulled accordingly. Therefore, the mechanical efficiency is higher than in the case of eccentric drive. Furthermore, sufficient assistance can be received until the end of the operation.

In the assist device provided with the clutch mechanism, when the actuator is rotated after the torque can be transmitted from the actuator to the transmission lever,
By rotating the transmission lever, the driven cable can be pulled and operated. Thereby, the parking brake can be easily applied. On the other hand, when the torque cannot be transmitted from the transmission lever side to the actuator side, manual operation can be easily performed with little resistance on the actuator side.

In the case of the assist device provided with the above-mentioned pulling force sensor, when the brake operation is manually started, the pulling force of the operation cable increases. When the pulling force sensor of the operation cable detects a pulling force equal to or more than a predetermined value, the actuator is driven to start the assist operation. Then, when the brake operation is completed, the pulling force of the driven cable increases, and the pulling force sensor of the driven cable detects this and stops the actuator. As described above, in the case of this assist device, the manual operation and the power operation by the actuator are naturally continuous.

When an electromagnetic clutch is used as the clutch mechanism, the electromagnetic clutch is turned on when the brake is applied by the actuator, and the electromagnetic clutch is turned off in other operation states such as when the brake is released and when the brake is manually operated. As described above, in this device, the transmission lever and the actuator can be freely connected and disconnected under the control of the electric circuit, so that various operation patterns such as switching between the operation by the actuator and the manual operation can be set relatively freely. can do.

In the case of an assist device in which the clutch mechanism is a one-way clutch, torque can be transmitted from the actuator side to the transmission lever side when the actuator is driven in the braking direction. Can be hung. When the brake is manually applied, since torque cannot be transmitted from the transmission lever side to the actuator side, the operation can be performed without being obstructed by the actuator side. When the brake is released, the clutch is in a direction in which torque can be transmitted as it is. Therefore, by driving the actuator in the reverse direction, the clutch is always in a state in which torque cannot be transmitted.
As a result, the brake can be manually released.

When the transmission lever is provided with an arc-shaped tooth row and meshes with the pinion, the deceleration action can be performed even at this portion, so that the mechanism becomes compact.

In the assist device in which the support member is driven, the operation cable and the driven cable are connected via the transmission lever when the actuator is not driven. Therefore, manual operation can be performed. In the case of driving the actuator, when the support member is moved in the direction in which the cable is pulled, the transmission lever rotates around the connection portion with the operation cable, and the driven cable can be pulled. When the actuator is driven in the opposite direction to move the support member in the opposite direction, the transmission lever rotates in the opposite direction about the connection portion with the operation cable, so that the pulling force of the driven cable can be reduced, The brake is released. Thus, in this assist device, the manual operation and the assist operation can be easily switched without using the clutch mechanism.

In the assist device in which the support member is a support lever having a rotation center on the opposite side of the support portion with the connection portion between the transmission lever and the operation cable interposed therebetween, the rotation movement from the actuator to the rotation of the transmission lever is performed. , The mechanical efficiency is higher. In the device using the toggle mechanism, a large operation force can be exerted at the end of the operation of applying the brake.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of an assist device according to the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing an embodiment of the assist device of the present invention, and FIG.
3 is a sectional view taken along line II-II, FIG. 3 is a plan view showing another embodiment of the assist device of the present invention, FIG. 4 is a sectional view taken along line IV-IV in FIG.
5 is an operation explanatory view of the apparatus of FIG. 3, FIG. 6 is a perspective view showing an embodiment of an arrangement state of the apparatus of FIG. 3, FIG. 7 is an electric circuit diagram showing an embodiment of a control circuit of the apparatus of FIG. 8 and 9
7 is a flowchart of a brake operation by the control circuit of FIG. 7, FIG. 10a is a perspective view showing another embodiment of the arrangement state of the apparatus of FIG. 3, and FIG. 10b is an electric circuit showing one embodiment of the control circuit of the apparatus of FIG. FIGS. 10C and 10D are flowcharts of the brake operation by the control circuit of FIG. 10B.

The assist device A shown in FIG. 1 and FIG.
A base plate 1, a support plate 2 provided with a space above it, and a suspension plate 4 suspended by a spacer rod 3 or the like below the support plate are provided. A motor M with a speed reducer G is mounted on the support plate 2. This motor with a speed reducer is the actuator of the first aspect. Further, a box-shaped cover 5 is covered around the support plate 2 including the motor M. The motor M is a DC motor that can rotate in both directions, and the speed reducer G is, for example, a worm speed reducer.

As shown in FIG. 2, an output shaft 7 of the speed reducer G penetrates below the support plate 2, and a shaft 8 is connected to the output shaft 7 so as to transmit torque. An electromagnetic clutch 9 having a shaft 8 as an input shaft is mounted on the suspension plate 4. Further, a first gear 10 is rotatably provided around the shaft 8, and the first gear 10 has a disk-shaped fixing portion 10 a fixed to the output rotating plate 11 of the electromagnetic clutch 7 with screws 12, and a first gear 10. And a small diameter gear portion 10b.

The first fixed between the support plate 2 and the suspension plate 4
An idler gear 15 is rotatably provided around the fixed shaft 14. The idler gear 15 is a large-diameter gear 15
a and a small-diameter gear 15b. The large-diameter gear 15a is the first
The gear 10 is engaged with the gear portion 10b. Furthermore, a second fixed shaft 16 fixed between the support plate 2 and the suspension plate 4
, A transmission lever 17 is provided rotatably. The transmission lever 17 has a semicircular shape as shown in FIG. 1, and a tooth row 17 a that meshes with the small-diameter gear 15 b of the idler gear 15 is formed on the circumference of the arc.

At both ends of the transmission lever 17, U-shaped connecting members 19 are rotatably mounted via pins 18, respectively. The connecting members 19 are provided with an operation cable 20 and a driven cable 21. The cable ends 20a and 21a fixed to the ends are engaged with each other. The operation cable 20 and the driven cable 21 are pull cables that transmit a pulling direction force, and have flexibility in which several metal wires are twisted. The cables 20, 21 are slidably guided by conduits 22, 23, the ends of which are connected to the side walls of the support plate 2 via known cable caps 24.
As the conduits 22 and 23, a flexible wire which is generally formed by spirally winding a metal wire and coating a synthetic resin is used. However, a non-flexible material such as a metal pipe may be used.

The operating cable 20 and its conduit 22 are
A pulling force sensor 2 that is connected to the brake operating lever 25 and detects a pulling force of the operating cable 20 in the middle thereof.
6 are provided. The driven cable 21 and its conduit 24 are connected to a center brake 27, and a pulling force sensor 28 for detecting a pulling force of the driven cable 21 is provided on the way. Each pulling force sensor 26, 28
May be a sensor that detects the magnitude of the pulling force as a numerical value, but here is a switch type sensor that outputs a contact signal or the like when a predetermined set value is exceeded.

The brake operation lever 25 may be a lever for operating a conventionally known parking brake of a vehicle, and is, for example, a manually operated lever provided rotatably with respect to a bracket mounted on the floor as shown in FIG. Operation lever is used. However, a foot-operated lever or a hand-operated lever may be used. The operation levers are connected to the operation cable 20 so that a pull operation can be performed. Further, a ratchet mechanism 31 is provided so that the operation cable 20 can be pulled to maintain the braked state.

The ratchet mechanism 31 is composed of, for example, a ratchet pawl 32 rotatably provided on the operation lever 25 and a ratchet teeth row 33 meshing with the ratchet pawl. Further, the operating lever 25 is provided with a rod 34 for releasing the ratchet. Note that some foot-operated levers have a separate ratchet release lever, and some hand-operated levers allow the ratchet to be turned in one direction to enable the ratchet, There is one that rotates to release the ratchet. The symbol EN in FIG. 6 is an engine,
Reference numeral TM denotes a transmission, reference numeral 27 denotes a center brake, and reference numeral DS denotes a drive shaft. Further, in this embodiment, a limit switch LS1 for detecting that the ratchet pawl 32 for the operation lever 25 is in the released state is provided.

In the assist device A configured as described above, the transmission lever 17 is disconnected from the motor M when the electromagnetic clutch 9 in FIG. Therefore, the operation cable 20 and the driven cable 21 are the same as those directly connected via the transmission lever 17. Therefore, when the operation cable 25 is pulled by operating the operation lever 25, the driven cable 21 is pulled and the center brake 27 is braked. Conversely, if the operating lever 25 is released after the ratchet mechanism is released, the pulling force of the driven cable 21 is weakened, and the braking action is released by the action of the return spring on the center brake 27 side.

On the other hand, when the electromagnetic clutch 9 is "engaged", the operation lever 25 cannot be freely operated by manual operation. In this case, when the motor M is rotated in one direction, the speed is reduced by the speed reducer G, and then the shaft 8 and the first gear 10 are rotated.
Rotates in the direction of arrow P. Therefore, the transmission lever 17 rotates in the arrow Q direction via the idler gear 15. Thereby, the driven cable 21 is pulled in the direction of the arrow S.
At this time, the large-diameter gear 15a of the idler gear 15 has more teeth than the gear portion 10b of the first gear 10, and the effective radius of the transmission lever 17 is larger than the small-diameter gear 15 of the idler gear 15, so that the gears are sequentially reduced. To go. Therefore, the driven cable 21 can be pulled with a considerably strong force. At this time, since the operation cable 20 is loosened, the operation lever 25 can be operated according to the speed.

As described above, the operation of applying and releasing the brake can be performed while the electromagnetic clutch is being turned on and off. In this embodiment, the timing of turning on and off the electromagnetic clutch is determined by the pulling force sensors 26 and 28 of the cable and the limit. The detection is performed semi-automatically upon detection of the switch LS1. That is, the pulling force sensor 26 of the operation cable 20 is turned on when detecting a pulling force of, for example, 7 kgf or more, and rotates the motor M in the normal rotation direction in which the driven cable is pulled. When the limit switch LS1 further detects that the ratchet mechanism has been released, the electromagnetic clutch 9 is turned "on" so that the motor M rotates in the direction in which the driven cable is pulled. Also,
The pulling force sensor 28 of the driven cable is turned on by a force larger than the operation cable, for example, a force of about 100 kgf,
The electromagnetic clutch 9 is disengaged.

From the above, the entire operation of the center brake 27 is as follows. [Pull Operation] (1) Pull the operation lever 25 without releasing the ratchet. Since the ratchet is not in the meshing direction, it can be pulled as it is. Until the operation cable 20 reaches a predetermined pulling force, the electromagnetic clutch 9 is "disengaged", so that the driven cable 21 is pulled manually.

(2) When the pulling force of the operation cable 20 reaches a predetermined value, the electromagnetic clutch 9 is turned on, the motor M rotates, and the driven cable 21 can be pulled by electric operation. Therefore, the operator only has to pull the operation lever 25 to the extent that the operation cable 20 is loosened.

(3) When the pulling force of the driven cable 21 reaches a predetermined value, the parking brake is firmly applied, and the motor M is stopped. At this time, the operating lever 25 is pulled to a degree that applies some tension to the operating cable 20, and the ratchet mechanism 31 is engaged.
Thereby, the braking force is maintained.

[Holding operation] In this state, the electromagnetic clutch 9 is in the "ON" state. However, the electromagnetic clutch 9 may be "OFF" when the engine is turned off. May be "cut".
Further, the electromagnetic clutch 9 may be set to "on" at all times, and when the action of the parking brake is weakened for some reason, the motor M may be automatically operated again to recover a predetermined braking force.

[Return Operation] The engagement of the ratchet mechanism 31 is released while slightly pulling the operation lever 25. As a result, the electromagnetic clutch 9 is in a “disengaged” state,
The operation lever 25 is returned to the original state (in FIG. 6, parallel to the floor) by manual operation. Driven cable 21
Since the load immediately decreases, the parking brake operation is released. When the electromagnetic clutch 9 is in the "on" state, the transmission lever 17 is held by the actuator in the stopped state and holds most of the pulling force of the driven cable 21, and the pulling force applied to the operation cable 20 is weak. Therefore, the ratchet can be easily removed, and the parking brake operation can be easily released.

Although the above embodiment employs an electromagnetic clutch as the clutch, a one-way clutch may be employed. In that case, the motor M side (shaft 8 side)
When the motor M is rotated in the direction in which the driven cable is pulled, the direction of the one-way clutch is set so that torque is transmitted to the first gear 10 side and free in the reverse direction. The pull force sensors 26 and 28 are used to rotate the motor M. The limit switch LS1 is also set as a condition for the rotation of the motor M. The operation of this embodiment is as follows.

[Pull Operation] (1) The operation lever 25 is pulled without releasing the ratchet. From the first gear 10 side,
Since the one-way clutch rotates in the free direction, the operation lever 25 can be pulled as it is. Also in this case, the motor M does not rotate until the operation cable 20 reaches a predetermined pulling force, and the driven cable 21 is manually pulled.

(2) When the pulling force of the operation cable 20 reaches a predetermined value, the motor M rotates in a direction to pull the driven cable. At this time, torque is transmitted from the motor side to the first gear side. Thereby, the driven cable 21 can be pulled by the electric operation by the motor M.

(3) When the pulling force of the driven cable 21 reaches a predetermined value, the parking brake is firmly applied, and the motor M is stopped.

[Holding operation] At this time, the one-way clutch is locked by the reaction force of the driven cable, and the braking force is maintained. It should be noted that the operating lever 25 is pulled to such an extent that some tension is applied to the operating cable 20, and the ratchet mechanism 31 is engaged. Even in the case of this embodiment, when the function of the parking brake is weakened for some reason, the motor M can be automatically operated again to recover a predetermined braking force.

[Return Operation] The engagement of the ratchet mechanism 31 is released while slightly pulling the operation lever 25. Next, the motor M is rotated in the reverse direction (rotated in the direction in which the operation cable is pulled). As a result, the one-way clutch is in a free state, so that the operation lever 25 can be returned to the original state by manual operation. Since the load on the driven cable 21 decreases immediately, the parking brake operation is released. When the motor M is stopped, the transmission lever 17
Is held by the actuator in the stopped state and holds most of the pulling force of the driven cable 21.
The pull on zero is weak. Therefore, the ratchet can be easily removed, and the parking brake operation can be easily released.

Next, another embodiment of the assist device will be described with reference to FIGS. The assist device B shown in FIG. 3 and FIG.
The center of rotation of 7 is configured to be movable in the cable pulling direction. That is, in this embodiment, the transmission lever 17
Is rotatably supported at one end of an L-shaped support lever 40. The center (L-shaped corner) of the support lever 40 has a cover 5 also serving as a support plate and a suspension plate 4. It is rotatably provided around the first fixed shaft 41 held between the first and second fixed shafts. The end of the operation cable 20 is rotatably connected between the center of rotation of the support lever 40 and the support of the transmission lever 17.

Further, a semi-circular drive lever 43 is rotatably provided around a second fixed shaft 42 provided in the vicinity of the speed reducer G, and a tooth row 43a provided on the arc-shaped peripheral edge thereof is provided. Are engaged with the teeth formed on the output shaft 7 of the speed reducer G. The other end of the connection link 44 rotatably connected to one end of the drive lever 43 is connected to the support lever 40.
Is rotatably connected to the other end. The engagement between the output shaft 7 and the drive lever 43 has a deceleration effect. Output shaft 7, drive lever 43, connecting link 44, support lever 40
The vertical relationship between the transmission lever 17 and the transmission lever 17 is shown in FIG. 2, but the length of each lever is deformed.

The operation cable 20 and the driven cable 21 rotatably connected to both ends of the transmission lever 17 and their conduits 22, 23 are substantially the same as those of the assist device A of FIG. Therefore, the same reference numerals are given and the description is omitted.

The assist device B configured as described above
When the motor M is stopped, the reduction gear G cannot be externally rotated by the self-restraining action. Therefore, the support lever 40 is restrained via the connection link 44 and the drive lever 43 and does not rotate. Therefore, the operation cable 20 and the driven cable 21 are mechanically substantially equivalent to a case where they are directly connected, and the parking brake can be applied and released by ordinary manual operation.

That is, when the operation cable 20 is pulled by pulling the brake operation lever, the transmission lever 17 rotates as indicated by an imaginary line, and the driven cable 21 can be pulled. On the other hand, return the operation lever to the operation cable 2
When the pulling force of 0 is weakened, the pulling force of the driven cable 21 is also weakened, so that the center brake is immediately released by the urging force of the return spring.

On the other hand, when the brake is applied by the driving force of the motor M, the motor M is driven so that the output shaft 7 of the speed reducer G is rotated clockwise (arrow P) in FIG. Thus, the drive lever 43 rotates counterclockwise, and the support lever 40 rotates counterclockwise via the connection link 44. As a result, the rotation center of the transmission lever 17 is pulled in the direction of the arrow R1, and the transmission lever 17 rotates in the direction of the arrow Q about the connection portion with the operation cable 20. Accordingly, the driven cable 21 is also pulled in the direction of the arrow R1, and the brake operation is performed. During the above operation, the operation cable 20 is not operated in the return direction because the operation lever is locked by the ratchet mechanism. At the end of the operation of pulling the driven cable 21, the first fixed shaft 14, which is the support point of the drive lever 43, the slide of the drive lever 43 and the connection link 44, and the slide of the connection link 44 and the support lever 40 are aligned. Line up close. As described above, the drive lever 43 and the connecting link 44 constitute a so-called toggle mechanism, so that the torque for restraining the support lever 40 is increased, and the parking brake can be applied with a strong force.

When releasing the brake, the motor M is rotated in the opposite direction (counterclockwise). Then, the support lever 40 rotates clockwise, and the pulling force of the driven cable 21 is reduced. Thereby, the parking brake is released. During this time, the operation cable 20 is not operated at all and does not move.

The assist device B is disposed in a side member 46 of a motor vehicle having a U-shaped cross section, for example, as shown in FIG. The conduit 22 of the operation cable 20 passes through the inside of the side member 46 to the lower part of the driver's seat, rises upward therefrom, and is fixed to a bracket 47 near the brake operation lever 25 of the parking brake. The end of the operation cable 20 is connected to the operation lever 25. The operation lever 25 is attached to a bracket (not shown) attached to the floor of the cab near the lower end so as to be rotatable around a horizontal axis. Further, the ratchet claw 32 provided on the operation lever 25 and the ratchet teeth row 33 attached to the vehicle body side are free when the operation lever 25 is raised and the direction in which the ratchet is locked in the returning direction as in the case described above. . A rod 34 for ratchet release is provided in the operation lever 25 so as to be movable in the axial direction.
The tip is in the form of a push button.

In the vicinity of the ratchet pawl 32, there is provided a limit switch LS1 for detecting a ratchet releasing state.
Limit switch LS for detecting whether or not 5 has been pulled
2 is mounted on the floor.

The driven cable conduit 23 is fixed to the case of the center brake 27, and the end of the driven cable is connected to a brake lever (not shown) of the center brake 27.

FIG. 7 is a circuit diagram showing a control circuit of the assist device B. As can be seen from this circuit diagram, in the present embodiment, unlike the assist device A of FIG. 1, a sensor that detects the pulling force of the cable is not used, and for example, an encoder 50 that detects the rotation angle of the drive lever is employed. The detected values are integrated by a flip-flop / counter FF and sent to a motor control circuit 51, which outputs signals for forward rotation, reverse rotation and stop of the motor. The encoder 50 includes a contact provided on a signal board 50a, a brush 50b provided on a drive lever, and the like. In addition,
Reference numeral 52 denotes a bridge circuit for normal rotation, reverse rotation, and short (regenerative braking). Reference numeral 53 denotes a signal line for sending an emergency stop signal to the motor control circuit 51 when the encoder 50 detects that the drive lever has overrun in the direction to apply the parking brake. Reference numeral 54 is a signal line for sending an emergency stop signal to the motor control circuit 51 when the drive lever overruns in the brake release direction.

Reference numeral 56 in FIG. 7 is, for example, a 24 volt battery used as a power source of an automobile, and reference numeral 57 is a regulator for reducing the pressure to 5 volts. LS1 is a limit switch for detecting ratchet release described above, and its output is sent to the motor control circuit 51 via a signal line 58 for sending a motor drive inhibition signal. Further, reference numeral LS2 is a limit switch for detecting operation of the operation cable, and its output is sent to the control circuit 51 via a signal line 59 for sending a parking brake start / release signal. A 24 volt power line 60 for driving the motor M
, An overload current detection circuit 61 is interposed. This circuit detects that an overload current has flowed through the motor when the brake is sufficiently applied or when an abnormality occurs in a driven cable or the like. Reference numeral 62 denotes a timer for sending a signal to the motor control circuit 51 when a predetermined time has elapsed since the start of the overload current.

A sensor 63 for detecting the vehicle speed or acceleration may be separately provided so that the motor M is restarted when the brake is released, or the set time of the timer is extended. Reference numeral 64 denotes a green LED lamp that indicates that the brake operation has been completed.
Reference numeral 5 denotes a red LED lamp for indicating that an overrun has occurred in the braking operation.

The operation of applying a brake by the control circuit constructed as described above will be described with reference to the flowchart of FIG. [Pull Operation] First, it is confirmed that the ratchet has not been released (step S1). Then, when you raise the operation lever with the ratchet not released,
Limit switch LS2 for detecting the operating state of the cable
Is switched from OFF to ON (step S2). During this time, for example, the switching can be performed only by one ratchet tooth (fast latch). However, it is also possible to switch after rotating by several teeth.

The motor M is rotated forward by the detection of the limit switch LS2 (step S3). In that case, FIG.
The operating cable 20 is also pulled through the transmission lever 17 of FIG. 5, but since the operating lever 25 is not returned by the engagement of the ratchet, only the driven cable 21 is pulled as shown in FIG. Next, the encoder constantly detects whether the parking brake is overrun or not (step S4), and immediately stops the motor immediately upon detection (step S5).
Further, at the same time, the red LED for displaying the abnormality warning is turned on (step S6).

When the motor M rotates forward to pull the driven cable and a sufficient tension is generated in the driven cable, an overcurrent flows through the motor M. When it is detected by the timer 62 that an overcurrent has flowed for a predetermined time or more (step S
7) The motor M is stopped (step S8). At the same time, the completion of the operation of applying the parking brake is indicated by turning on the green LED (step S
9).

[Return Operation] To release the brake,
Release the ratchet of the control lever 25 and return it somewhat. When this is detected by the cable operation detection limit switch LS2 (step S10 in FIG. 9), the motor M is rotated reversely (step S11). As a result, the pulling force of the driven cable is reduced, and the parking brake is released. It is to be noted that the encoder always detects whether or not the drive lever is overrun (Step S12), and when the overrun occurs, the motor M is stopped immediately (Step S13), and the red LED of the abnormality warning display is turned on (Step S13). S14).

When the motor M is rotating in the reverse direction, the encoder detects a predetermined number of pulses (step S15), and stops the motor M when the predetermined number of pulses is reached (step S16). At that time, the green LED is turned off to display the brake release (step S17).

In the case of the assist device equipped with the speed or acceleration sensor shown in FIG. 7, when the vehicle's speed sensor or acceleration sensor detects that the vehicle has moved somewhat while the parking brake has been applied, the timer value is set. , The motor M is immediately rotated forward. As a result, the driven cable is further pulled and operated,
Apply extra brakes.

In the above-mentioned operation, the case where the operation lever is raised without releasing the ratchet has been described. However, the operation lever 25 is manually raised while pushing the rod (reference numeral 34 in FIG. 6) for releasing the ratchet. The ratchet may be engaged by releasing the rod. In that case, after the ratchet is turned on, the motor M
Rotates and starts pulling the driven cable 21. As described above, in this embodiment, it is possible to select a pattern in which almost the entire operation is electrically operated and a pattern in which the operation is partially performed manually, depending on how the operation lever is operated.

Next, referring to FIGS. 10A to 10C, FIG.
Other embodiments of the control methods of the assist device B of (1) to (4) will be described. As shown in FIG. 10A, in this embodiment, a limit switch for detecting the release state of the ratchet mechanism is not provided, and instead, an electric operation switch SW1 including a changeover switch is provided. This electric operation switch SW is provided at the same position as the limit switch LS1 in the circuit of FIG. 7 as shown in FIG. 10b, and selects a signal line 64 for sending an electric start signal and a signal line 65 for sending an electric release signal to control the motor. The signal is sent to the circuit 51. Reference numeral SW2 denotes a manually operated switch, which can be substantially the same as the above-described limit switch LS1, and is provided at the same position in the control circuit as shown in FIG. 10B. The output is sent to the motor control circuit 51 via a signal line 59 for sending a parking brake start / release signal.

In the assist device provided with this control circuit, as shown in the flowchart of FIG. 10C, first, ON / OFF of the manual operation switch SW2 is detected (step S21), and when the operation lever 25 is operated, Move to the next step. Then, when the electric operation switch SW is switched from the electric power release signal line 65 to the electric start signal line 64 (step S22), the motor M starts normal rotation. After that, it is the same as the case of FIG. To return the operation lever 25, as shown in FIG. 10D, when the electric operation switch SW1 is switched from the electric start signal line 64 to the electric release signal line 65 (step S23), the motor M starts to reversely rotate. After that, it is the same as the case of FIG.

In FIG. 10C, when the operation lever 25 is pulled up without switching the electric switch SW1 on the way, the operation cable 20 is pulled while the support lever 40 is fixed at the original position, and the transmission cable is moved. Only the pivot is turned in the direction of arrow Q, the driven cable 21 is pulled, and the parking brake can be manually applied as it is. When releasing by manual operation, the ratchet of the operation lever 25 is released in the same manner as a normal parking brake, and when the operation cable 20 is returned, the transmission lever 17 rotates in the direction opposite to the arrow Q, and the driven cable 21 returns,
The parking brake can be released.

In the assist device B shown in FIG. 3, the motor can be controlled by using a sensor for detecting the pulling force of the cable as in the case of FIG. Further, the control circuit of FIG. 7 can also be employed in the assist device A of FIG.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of an assist device of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a plan view showing another embodiment of the assist device of the present invention.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

FIG. 5 is an operation explanatory view of the device of FIG. 3;

FIG. 6 is a perspective view showing an embodiment of an arrangement state of the apparatus of FIG. 3;

FIG. 7 is an electric circuit diagram showing one embodiment of a control circuit of the device of FIG. 6;

FIG. 8 is a flowchart of a brake operation by the control circuit of FIG. 7;

FIG. 9 is a flowchart of a brake release operation by the control circuit of FIG. 7;

10a is a perspective view showing another embodiment of the arrangement state of the apparatus of FIG. 3, FIG. 10b is an electric circuit diagram showing one embodiment of a control circuit of the apparatus of FIG. 10a, and FIGS. 10c and 10d are It is a flowchart of the brake operation and brake release operation by the control circuit of FIG. 10b, respectively.

FIG. 11 is a plan view showing an example of a conventional parking brake assist device.

[Explanation of symbols]

 Reference Signs List A Assist device 1 Base plate 2 Support plate 3 Spacer rod 4 Suspension plate G Reducer M Motor 5 Cover 7 Output shaft 8 Shaft 9 Electromagnetic clutch 10 First gear 14 First fixed shaft 15 Idler gear 16 Second fixed shaft 17 Transmission lever 20 Operation cable 21 Follower cable 22, 23 Conduit 24 Cable cap 25 Operation lever 26, 28 Pull force sensor 27 Center brake 31 Ratchet mechanism 34 Rod EN Engine TM Transmission DS Drive shaft LS1 Limit switch 40 Support lever 43 Drive lever 44 Linkage link 50 Encoder 51 Motor control circuit 56 Battery 57 Regulator 61 Overload current detection circuit 62 Timer 63 Vehicle speed / acceleration sensor 64 Red LED 65 Green LED

Claims (9)

[Claims] A transmission lever rotatably supported in the vicinity of an intermediate portion; an operation cable rotatably connected to one end of the transmission lever for connecting between the transmission lever and a brake operation lever; An assisting device for a parking brake, comprising: a driven cable rotatably connected to the other end of the lever for connecting the transmission lever to the parking brake; and an actuator for driving the transmission lever to rotate. 2. A clutch mechanism which can select between a state where torque can be transmitted from the actuator side to the transmission lever side and a state where torque transmission from the transmission lever side to the actuator side is disabled between the actuator side and the transmission lever side. The assist device according to claim 1, further comprising: 3. A pulling force sensor is provided on each of the operation cable and the driven cable, and when the pulling force sensor of the operation cable detects a predetermined or more pulling force, the actuator is driven in a direction to pull the driven cable; The assist device according to claim 1, further comprising a control circuit that stops the actuator when the pulling force sensor of the driven cable detects a predetermined or more pulling force. 4. The assist device according to claim 2, wherein the clutch mechanism is an electromagnetic clutch that turns on and off torque transmission between the actuator side and the transmission lever side. 5. A one-way clutch which, when viewed from the actuator side, transmits torque to the transmission lever side when rotating the transmission lever in a direction in which the driven cable is pulled, and is free in the opposite direction. The assist device according to claim 2. 6. The assist device according to claim 1, wherein the transmission lever has an arc-shaped tooth row centered on a rotation center, and a pinion driven by an actuator meshes with the tooth row. 7. A support member rotatably supporting the transmission lever is provided movably in a direction substantially parallel to a moving direction of the cable, and the actuator drives the support member in a pulling direction of the cable. The assist device according to claim 1, wherein the transmission lever is configured to rotate around the connecting portion of the operation cable. 8. The support member is a support lever having a center of rotation on a side opposite to the support portion across a connecting portion between the transmission lever and the operation cable, and the actuator drives the support lever to rotate. The assist device according to claim 7, wherein the assist device is configured as follows. 9. A driving lever driven by the actuator, and a connecting lever connecting the driving lever and the support lever, wherein the driving lever includes:
9. The assist device according to claim 8, wherein the connection lever and the support lever form a toggle mechanism such that when the drive lever is rotated in a direction in which the driven cable is pulled, the angle between the drive lever and the connection lever is close to a straight line. .