JPH03186467A - Parking brake device - Google Patents

Abstract

PURPOSE:To exert a correct power assist function regardless of an abrupt brake action by improving the structure around a brake action detecting section in a system detecting a brake action to operate an actuator and pull a brake cable. CONSTITUTION:When an action lever 1 is pulled for a brake action, the first connecting member 4 is moved in the direction X relatively to the second connecting member 5, a relative displacement detecting switch 10 is pressed by a step section 12 to output an on-signal, and the winding action of a cable 7 by an actuator 2 is started. The actuator 2 is stopped when the relative displacement detecting switch 10 is separated from the step section 12 after the pulling action of the action lever 1 is stopped. A cable 19 is pulled by the movement of a balance lever 3 caused by the movement of both connecting members 4, 5, and brake units 17, 18 are operated. In this device, the lead stroke L between a stopper 9 and a recess 8 is set larger than before.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a parking brake device having a boosting mechanism for reducing the operating force of a brake operating lever.

[Prior Art] A conventional parking brake device has a configuration shown in FIG. 4. In the same figure, 1 is an operating lever, 2
3 is an electric actuator, 3 is a balance lever, and a first connecting member 4 and a second connecting member 5 are respectively swingably connected to both ends of the balance lever 3.
The cable 6 from the operation lever 1 is connected to the end of the second
A cable 7 from the actuator 2 is connected to the terminal end of the connecting member 5 .

A recess 8 is formed approximately in the center of the first connecting member 4,
A stopper 9 protruding from the central portion of the second connecting member 5 is inserted into the recess 8.

Reference numeral 10 denotes a first relative displacement detection switch fixed to the second connecting member 5, and detection is performed by displacing the first connecting member 4 in the X direction in the figure with respect to the second connecting member 5. When the contact 11 is pressed by the step 12 of the first connecting member 4,
Outputs on signal.

Reference numeral 13 denotes a second relative displacement detection switch fixed to the second connecting member 5, and detects the displacement by displacing the first connecting member 4 in the direction opposite to the arrow X with respect to the second connecting member 5. When the contact 14 is pressed against the stepped portion 15 of the first connecting member 4, it outputs an on signal.

Note that when the relative displacement detection switch 10 or 13 outputs an on signal due to relative displacement between the first connecting member 4 and the second connecting member 5, the stopper 9 comes into contact with the recess 8 to restrict excessive relative displacement. The gap between the stopper 9 and the recess 8 is set as follows.

Reference numeral 16 denotes a control circuit for controlling the drive of the actuator 2, which causes the actuator 2 to perform a forward rotation operation for winding the cable 7 in accordance with the ON signal from the first relative displacement detection switch IO, and detects the second relative displacement. The actuator 2 is caused to perform a reverse rotation operation to loosen the cable 7 according to the on signal from the detection switch 13, and further, the actuator 2 is stopped when no on signal is output from any relative displacement detection switch 10.13. .

Reference numeral 17 and 18 denote a brake unit installed, for example, in the rear wheel, which is connected to the center portion of the balance lever 3 via a cable 19, and controls the amount by which the cable 19 is pulled by the movement of the balance lever 3 in the X' direction. perform an action.

Next, the operation will be explained. First, when the operating lever 1 is pulled to perform a brake operation, the first connecting member 4 moves in the X direction relative to the second connecting member 5, and the relative displacement detection switch 10 presses against the stepped portion 12. As a result, an on signal is output, and the winding operation of the cable 7 by the actuator 2 is started.

The relative displacement detection switch 10 connects the first connecting member 4 and the second connecting member 4.
As long as the relative displacement of the connecting member 5 continues, the ON signal continues to be output, and the winding operation of the cable 7 by the actuator 2 continues.

Then, when the user stops pulling the operating lever 1, the actuator 2 continues the winding operation of the cable 7 for a while, and when the relative displacement detection switch 10 leaves the stepped portion 12, the winding operation of the actuator 2 stops.

In this way, in response to the displacement of the first connecting member 4 according to the operating stroke of the operating lever 1, the actuator 2 moves the second connecting member 5 to eliminate the displacement, and the relative displacement detection switch 10 moves the second connecting member 5 to eliminate the displacement. The actuator 2 is driven until there is no displacement. And the first. By pulling the cable 19 by moving the balance lever 3 along with the movement of the second connecting members 4, 5, the brake unit 17.18
When the actuator 2 performs braking according to the operating stroke, the operating force is reduced by the power assist of the actuator 2.

On the other hand, when the operating lever 1 is operated from braking to releasing the brake, the first connecting member 4 moves in the direction opposite to the arrow X in FIG. 2, the relative displacement detection switch 13 is pressed by the stepped portion 15 and outputs an on signal, and the actuator 2 starts loosening the cable 7. Ru. Relative displacement detection switch 1
3 continues to output the ON signal as long as the relative displacement between the first connecting member 4 and the second connecting member 5 continues, and the loosening operation of the cable 7 by the actuator 2 continues.

Then, the second connecting member 5 follows the first connecting member 4, and the loosening operation of the actuator 2 stops when the relative displacement detection switch 13 separates from the stepped portion 15. Through this series of operations, the first. The braking is released by loosening the cable 19 by moving the balance lever 3 in conjunction with the movement of the second coupling member 4.5.

In this way, the parking brake device has an advantage in that the power assist of the actuator 2 allows the braking operation to be performed by simply pulling the operating lever 1 lightly.

[Problems to be Solved by the Invention] However, in such conventional parking brake devices, when the operating lever is pulled relatively slowly to perform a braking operation, the actuator follows and reduces the operating force. However, there is a problem in that when the operating lever is pulled suddenly, the actuator cannot follow the action and the operating force cannot be reduced.

That is, to explain based on FIG. 5, when the operating lever 1 is pulled suddenly, the operating stroke increases rapidly as time passes as shown by curve A in the figure, and the winding stroke of the cable 7 by the actuator increases. increases as shown by curve B in the figure. However, since the actuator 2 is delayed in following the operating lever 1, the actuator 2 only takes up the slack in the cable 7 while the operating lever 1 is pulled to its maximum stroke (at the time to -ti >). The power assist is not exerted, therefore, the braking operating force during this period becomes the operating force of the operating lever.Then, at time t2 after the operating lever 1 has been pulled to its maximum stroke, the actuator 2 After winding up the slack in 7, actuator 2
Braking operation is performed using power assist. That is, this braking operation force can be expressed as a movement stroke of the balance lever 3, so it becomes like the curve C in FIG. In the curve C, the period from time tO to tl corresponds to the operating force of the operator himself, and the period from time t2 to t3 corresponds to the operating force due to the power assist of the actuator 2.

However, since the period of power assist by the actuator 2 (times t2 to t3) is short, it hardly contributes to reducing the amount of operation.

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a parking brake device that exhibits a power assist function using an actuator even if the operator performs a sudden braking operation. do.

[Means for Solving the Problems] In order to achieve such an object, the present invention includes an operating lever, an actuator, an operating force of the operating lever acts on one end of the operating lever via a first connecting member, and the operating force of the operating lever acts on the other end of the actuator. a balance lever on which the actuating force of the actuator acts via a second coupling member and a parking brake applied on an intermediate portion; and a balance lever that detects the relative displacement of the second coupling member with respect to the first coupling member. displacement detecting means, control means for controlling the drive of the actuator so as to reduce the relative displacement detected by the relative displacement detecting means, and a relative displacement of the second connecting member with respect to the first connecting member being preset. In the parking brake device, the regulating means controls the second coupling member relative to the first coupling member at the time when the actuator starts operating according to the detection by the relative displacement detection means. The distance between the relative displacement of the second connecting member and the point at which the relative displacement of the second connecting member with respect to the first connecting member is restricted, that is, the lead stroke was increased.

In one embodiment, the regulating means is a mechanism that regulates mutual displacement by bringing the members into contact with each other when the relative displacement of the second coupling member with respect to the first coupling member reaches a predetermined range; The lead stroke until it makes contact has been increased.

Further, the lead stroke is set so that the operating stroke of the operating lever is the same whether the operating lever is operated rapidly or slowly.

[Function] According to the present invention having such a configuration, even if the operating lever is suddenly operated, the range in which the power assist by the actuator acts will be expanded by the amount of the lead stroke expanded. , compared to the conventional
The operating force of the operating lever can be reduced. In addition, the lead stroke is set so that the operating stroke of the operating lever is the same whether the operating lever is operated rapidly or slowly. It is possible to obtain braking and give the operator a sense of security.

[Example] An example of the present invention will be described below with reference to FIG. still,
In FIG. 1, the same or corresponding parts in FIG. 4 are designated by the same reference numerals.

To explain the difference from the conventional example, the gap interval (lead stroke) L between the stopper 9 and the recess 8 is set larger than that of the conventional example.

In such a configuration, when a brake operation is performed by rapidly pulling the operating lever 1 to the maximum stroke IM in a short period of time from time tO to time tl, as shown by curve a in FIG. 2, for example, the first connecting member 4 moves in the X direction relative to the second connecting member 5, and the relative displacement detection switch 10
is pressed by the stepped portion 12, outputting an ON signal, and the winding operation of the cable 7 by the actuator 2 is started, and the winding stroke of the cable 7 increases as shown by the curved line in FIG. Furthermore, during this period tO to tl, the recess 8
When the second connecting member 5 and the balance lever 3 come into contact with the stopper 9, the second connecting member 5 and the balance lever 3 follow the first connecting member 4 and move in the X direction, thereby performing a braking operation of the brake units 17 and 18. Therefore, during the period tO to tl, the actuator 2 does not follow, so power assist is not exerted, and braking is performed by the operating force of the operator.

Then, at time t3 after the operating lever l has been pulled to its maximum stroke, the actuator 2
After winding up the slack, a braking operation is performed by power assisting the actuator 2. Since the power assist is exerted until the cable 7 corresponding to one lead stroke is wound up, the range in which the power assist of the actuator 2 is exerted is expanded compared to the conventional case.

That is, as shown in curve C in FIG. 2, the period tO~tl
The movement stroke of the balance lever 3 at is due to the operating force of the operator, and after the period t3, it is due to the power assist by the actuator 2, and the range in which the operating force can be reduced is expanded compared to the past. .

Furthermore, the effect of enlarging the lead stroke L will be described with reference to the relationship between the operating stroke and the operating force in FIG. Conventionally, there was almost no lead stroke, so if the control lever was suddenly pulled, the operator would have to use the operator's operating force to perform braking until the maximum operating stroke of 1h was reached, which required a large amount of operating force (see Figure 3). (See song lid).

On the other hand, in this embodiment, by enlarging the lead stroke L, the maximum stroke i! , braking is performed by the operating force of the operator up to the stroke 2M, which is the amount by which the extended stroke L is subtracted, but the remaining stroke L is braked by the operating force provided by the power assist of the actuator 2. Therefore, as shown by the curve e in FIG. 3, the power assist of the actuator 2 is more effectively exerted than in the past.

Furthermore, although the curve f in FIG. 3 shows the case where the operating lever 2 is pulled slowly, according to this embodiment, even when the operating lever 2 is pulled suddenly, it is different from when the operating lever 2 is pulled slowly. Since they have similar characteristics, it is possible to give the operator the same feeling of operation.

[Effects of the Invention] As explained above, according to the present invention, even when the operation lever is suddenly operated, the range in which the power assist by the actuator acts is expanded by the increase in the lead stroke. Therefore, the operating force of the operating lever can be reduced compared to the conventional case. In addition, the lead stroke is set so that the operating stroke of the operating lever is the same whether the operating lever is operated rapidly or slowly. It is possible to obtain braking and give the operator a sense of security.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the configuration of an embodiment according to the present invention, FIGS. 2 and 3 are characteristic curve diagrams explaining the operation of the embodiment, and FIG. 4 is a conventional diagram showing the configuration of a conventional example. FIG. 5 is a characteristic curve diagram illustrating the operation of the conventional example. Codes in the figure: ]; Operation 1; Collar 2; Actuator 3; Balance lever 4: First connecting member 5; Second connecting member 6, cable 7, cable 8; recess 9, stopper relative displacement detection switch detection contact stage Part relative displacement detection switch Detection contact Step part control circuit Brake unit Brake unit cable

Claims (2)

[Claims] (1) An operating lever and an actuator, the operating force of the operating lever acts on one end via a first connecting member, the operating force of the actuator acts on the other end via a second connecting member, and the intermediate a balance lever on which a parking brake force is applied; a relative displacement detection means for detecting a relative displacement of the second connection member with respect to the first connection member; a control means for controlling driving of the actuator;
In the parking brake device, the regulating means regulates the relative displacement of the second coupling member with respect to the coupling member within a preset range, wherein the regulating means controls the actuator according to the detection by the relative displacement detection means. It is characterized by increasing the relative displacement of the second connecting member with respect to the first connecting member at the time of starting operation and the lead stroke until the relative displacement of the second connecting member with respect to the first connecting member is regulated. Parking brake device. (2) The lead stroke is set so that the operation stroke of the operation lever is the same when the operation lever is operated rapidly to the extent that the actuator cannot follow it and when it is operated slowly. 1) Parking brake device.