JPH05301565A - Pedal ratio varying brake pedal device - Google Patents

Abstract

(57) [Summary] [Object] The present invention is a pedal ratio variable brake pedal device in which the pedal ratio increases as the pedal is depressed in order to obtain a larger braking force with the same pedaling force during emergency braking. The purpose is to keep the pedal ratio constant. [Structure] The pedaling force applied to the pedal portion 2 is set to be larger than a first predetermined pedaling force with which the assisting device 5 can assist the pedaling force at a constant rate, and larger than a pedaling force within a range that is normally scheduled. When the second predetermined pedal effort is reached, the pedal ratio is increased by the pedal ratio changing means (10, 11).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pedal ratio variable brake pedal device capable of changing a pedal ratio, and more particularly, in order to obtain a larger braking force with the same pedaling force during emergency braking, the pedal pedal is depressed as the pedal is depressed. The present invention relates to a variable pedal ratio brake pedal device that increases the ratio.

[0002]

2. Description of the Related Art As shown in FIG. 6, a pedal ratio means a pedal portion from a turning point A of a pedal arm to a distance a from a turning point A of a pedal arm to a connecting point B of a push rod with a pedal arm. Ratio b of distance b to the center point C of
/ A. If this pedal ratio is large, a larger push rod operation amount, that is, a braking force can be obtained for the same pedaling force applied to the pedal portion by the lever principle.

An example of a variable pedal ratio brake pedal device which increases the pedal ratio as the brake pedal is depressed is the variable pedal ratio brake pedal device disclosed in Japanese Utility Model Laid-Open No. 53-16236.

The variable pedal ratio brake pedal device disclosed in Japanese Utility Model Laid-Open No. 53-16236 will be described with reference to FIGS. 7 and 8. In FIG. 7, reference numeral 71 denotes a pedal arm, and a pedal portion 72 and a pin 73 are integrally provided in each of the elongated holes.
Has 74. A bracket 75 is attached to the vehicle body, and is provided with a pin 76 and an elongated hole 77. The pin 73 of the pedal arm 71 is engaged with the elongated hole 77 of the bracket 75, while the pin 76 of the bracket 75 is engaged with the elongated hole 74 of the pedal arm 71. Here, the pin 73 of the pedal arm 71 can move in the long hole 77 of the bracket 75.
76 is movable in the long hole 74 of the pedal arm 71. A spring 78 is attached between the upper end of the pedal arm 71 in the figure and the bracket 75.
The pedal arm 71 is biased so that the pin 73 of 71 is located at the upper end of the oblong hole 77 of the bracket 75 in the figure. Pedal arm
A push rod 80 of a master cylinder 79 is connected via a pin 81 to the lower side of the oblong hole 74 of 71 in the drawing.

Here, the long hole 74 of the pedal arm 71 and the long hole 77 of the bracket 75 will be described in detail. Pedal arm
The shape of the long hole 74 of 71 is determined so that the pedal arm 71 can rotate around the pin 73. The shape of the long hole 77 of the bracket 75 is determined so that the pedal arm 71 can rotate around the pin 76 of the bracket 75 engaged with the lower end of the long hole 74 of the pedal arm 71 in the figure. Is.

The operation of the variable pedal ratio brake pedal device configured as described above will be described. In the non-actuated state of the variable pedal ratio brake pedal device, it is in the original position shown in FIG. When the pedal portion 72 is depressed from this state, the pedal arm 71 rotates around the pin 73. The pedal ratio at this time is relative to the distance a ₁ from the center point D of the pin 73, which is the pivot point of the pedal arm 71, to the center point E of the pin 81, which is the connection point of the push rod 80 with the pedal arm 71. The ratio b ₁ / a ₁ of the distance b ₁ from the center point D of the pin 73, which is the pivot point of the pedal arm 71, to the center point F of the pedal portion 72.

Further, the pedal portion 72 is further depressed, and as shown in FIG. 8, the pin 76 of the bracket 75 is attached to the elongated hole 74 of the pedal arm 71.
After engaging the lower end in the figure, the pedal arm 71
Rotate around. The pedal ratio at this time is from the center point G of the pin 74, which is the pivot point of the pedal arm 71, to the pin 81, which is the connection point of the push rod 80 with the pedal arm 71.
The ratio b ₂ / a ₂ of the distance b ₂ from the center point G of the pin 74, which is the pivot point of the pedal arm 71, to the center point F of the pedal portion 72, with respect to the distance a ₂ to the center point E of. ..

Here, b ₂ / a ₂ > b ₁ / a ₁ , and the pedal ratio is large.

In such a pedal ratio variable brake pedal device, by adjusting the length of the long hole 74 of the pedal arm 71, the pedal stroke where the pedal ratio changes can be arbitrarily determined.

[0010]

However, as a result of experiments conducted by the inventor of the present application, when the pedal ratio is increased during normal braking, the feeling of pedaling becomes softer and the feeling becomes worse. The pedal ratio does not change when the pedal is operated within the planned range during braking, and the pedal ratio is increased only when there is pedal operation that exceeds the planned range during normal braking (for example, during emergency braking). It has been found necessary to configure a variable pedal ratio brake pedal system to However, if an attempt is made to achieve such a configuration by means of the above-mentioned conventional technique, the following problems will occur.

Brake devices are usually provided with assisting devices to reduce the pedal effort. This assisting device increases the pedal depression force at a predetermined rate until the pedal depression force reaches a certain prescribed depression force, and increases the pedal depression force by a prescribed value irrespective of the magnitude of the depression force after the pedal depression force reaches the prescribed depression force. It is then transmitted to the master cylinder. With this assisting device, the relationship between the pedal effort and the pedal stroke is as shown by the solid line in FIG. The broken line graph represents the relationship between the pedal effort and the pedal stroke when the assisting device is not provided or when the assisting device fails and no assisting force is obtained. The difference between the solid line graph and the broken line graph is the pedal effort increased by the assisting device. In the figure, a is the above-mentioned predetermined pedaling force, and according to the graph shown by the solid line,
It can be seen that after the pedal effort exceeds a, the pedal stroke hardly increases even if the pedal effort increases.

Further, generally, the range of pedal effort corresponding to the pedal operation in the range expected during normal braking is the range enclosed by parentheses in the figure, and the pedal effort equivalent to the emergency braking is in the figure. It has become b. In other words, the pedal operation is still within the range planned for normal braking even after exceeding a. The pedal stroke is in a state where the pedal stroke hardly changes around the boundary of the range that is scheduled during normal braking.

Further, in the brake pedal device, in general, a slight difference in pedal stroke often occurs due to, for example, an assembly error. Therefore, for example, in a conventional pedal ratio variable brake pedal device, consider a case where the relationship between the pedal depression force and the pedal stroke is as shown by the one-dot chain line in FIG.

In the conventional pedal ratio variable brake pedal device, it is assumed that the pedal stroke where the pedal ratio becomes large is such that the relationship between the pedal depression force and the pedal stroke is as shown by the solid line in FIG.
In the figure, the pedal ratio is increased when there is a pedal stroke (during emergency braking). However, in reality, the relationship between the pedal depression force and the pedal stroke is as shown by the one-dot chain line graph, and when there is a pedal stroke of c, the pedal ratio increases,
The pedal ratio will increase due to the pedal effort of D. In other words, the area where the pedal ratio becomes large falls within the range of pedal operation scheduled for normal braking. As described above, the conventional pedal ratio variable brake pedal device has a problem that the pedal ratio may increase during normal braking, resulting in poor feeling.

It is an object of the present invention to make sure that a normal brake and an emergency brake are determined by determining the point where the pedal ratio becomes large by the pedal effort, and keep the pedal ratio constant during normal braking. To do.

[0016]

In order to solve the above problems, a pedal ratio variable brake pedal device of the present invention has a pedal portion at one end and is rotatably supported by the vehicle body at the other end. A push rod for transmitting the pedaling force applied to the pedal portion to the master cylinder, a connecting means for connecting the push rod and the pedal arm, and the pedaling force at a predetermined ratio until the pedaling force reaches a first predetermined pedaling force. And the pedaling force increases by a predetermined value irrespective of the magnitude of the pedaling force after the pedaling force reaches the first predetermined pedaling force, and the pedaling force is transmitted to the master cylinder by the first pedaling force. Only when the pedaling force is greater than a predetermined pedaling force and is equal to or greater than a second predetermined pedaling force that is set to be larger than the pedaling force in a range that is planned during normal braking, the connecting point is moved from the pivot point of the pedal arm to the connecting means. The ratio of the distance from the pivot point of the pedal arm to the center point of the pedal portion to the distance to the position on the pedal arm is made larger than the ratio until the pedal force reaches the second predetermined pedal force. And a pedal ratio varying means.

[0017]

According to the above means, when the pedal force is applied to the pedal portion, the pedal arm rotates about the support portion for the vehicle body, and the pedal force connected to the pedal arm transmits the pedal force to the master cylinder. When the pedal effort exceeds the first predetermined pedal effort and the assistance mode of the pedal effort by the assisting device changes from an increase of a predetermined proportion of the pedal effort to an increase of a predetermined value irrelevant to the pedal effort, the stroke of the pedal portion becomes extremely small. .. According to the pedal ratio varying means, the pedaling force within a range such that the stroke of the pedal portion becomes extremely small,
In addition, the pedal ratio is increased when the pedaling force exceeds the second predetermined pedaling force, which is defined as a pedaling force that exceeds the range that is scheduled during normal braking. Here, the pedal ratio is the distance from the pivot point of the pedal arm to the center point of the pedal portion with respect to the distance from the pivot point of the pedal arm to the position where the push rod is connected to the pedal arm. It is set as a ratio.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A first embodiment of the present invention will be described with reference to FIGS.
It will be explained based on. Reference numeral 1 denotes a pedal arm, which has a pedal portion 2 at one end and is rotatably attached to the vehicle body by a pin 3 at the other end. Reference numeral 4 denotes a push rod, which transmits a pedaling force applied to the pedal portion 2 (hereinafter referred to as pedaling force) to the master cylinder 6 via the assisting device 5. Here, the assisting device 5 increases the pedal depression force at a predetermined rate until the pedal depression force reaches a certain prescribed depression force, and after the pedal depression force reaches the prescribed depression force, the pedal depression force does not depend on the magnitude of the depression force. Increase by the value and master cylinder 6
To tell. Further, the master cylinder 6 generates a hydraulic pressure according to the operation amount of the push rod 4, and the hydraulic pressure is transmitted to a wheel cylinder (not shown) to generate a braking force on wheels (not shown). It is a thing. The other end of a link 8 having a pin 7 integrally attached to one end thereof is rotatably attached to the pedal arm 1 by a pin 9. The pin 7 at one end of the link 8 is engaged with an elongated hole 10 provided in the pedal arm 1, and the elongated hole 10 is connected to the elongated hole 10.
The shape is determined so as to be rotatable around the pin 9. The push rod 4 is connected to the pin 7 at one end of the link 8 and one end of the spring 11 is attached. The other end of the spring 11 is attached to the pedal arm 1, and the spring 11 urges the link 8 downward in the drawing.

The operation of the variable pedal ratio brake pedal device configured as described above will be described. The variable pedal ratio brake pedal device is in the original position shown in FIG. When the pedal portion 2 is depressed from this state, the pedal arm 1 rotates about the pin 3 and the push rod 4
Transmits the pedaling force to the master cylinder 6 via the assisting device 5 while keeping the position on the pedal arm 1 at the lower end of the elongated hole 10 in the figure. The reaction force (F) from the master cylinder 6 transmitted to the push rod 4 is also divided into a direction of the elongated hole 10 (f) as shown in FIG. 3, so that the push rod 4 moves its position on the pedal arm 1. Attempt to move the slot 10 upward in the figure. At the same time, the reaction force (F) from the master cylinder 6
The biasing force of the spring 11 is larger than the component force (f) of the above, and the upward movement of the elongated hole 10 of the push rod 4 in the figure is prevented. The pedal ratio at this time is from the center point H of the pin 3 which is the pivot point of the pedal arm 1 to the pin 7 which is the connection point of the push rod 4 with the pedal arm 1.
Ratio b ₃ / a ₃ of the distance b ₃ from the center point H of the pin 3 which is the pivot point of the pedal arm 1 to the center point J of the pedal portion 2 with respect to the distance a ₃ to the center point I of the pedal portion 1. ..

When the pedal portion 2 is further depressed and the component force (f) of the reaction force (F) from the master cylinder 6 transmitted to the push rod 4 becomes larger than the biasing force of the spring 11, the push rod 4 is pushed. The elongated hole 10 is allowed to move upward in the figure, and as shown in FIG.
The position on the pedal arm 1 is set as the upper end of the slot 10 in the figure, and the pedal force is applied to the master cylinder 6 via the assisting device 5.
Tell. The pedal ratio at this time is from the center point H of the pin 3 which is the turning point of the pedal arm 1 to the push rod 4
From the center point H of the pin 3 which is the turning point of the pedal arm 1 to the center point J of the pedal portion 2 with respect to the distance a ₄ to the center point K of the pin 7 which is the connection point with the pedal arm 1. distance
b is the ratio b ₃ / a _{4 3.}

The pedal ratios of the two states will be compared. _{b 3 / a 4 -b 3 /} a 3 = (a 3 -a 4) a b ₃ / a ₃ a _4, because it is _{a 3 -a 4> 0, b} 3 / a 4 -b 3 / a It is clear that ₃ > 0 is blocked and b ₃ / a ₄ > b ₃ / a ₃ and the pedal ratio is large.

In the above-described variable pedal ratio brake pedal device, the pedal effort is larger than the first predetermined pedal effort that the assisting device can assist the pedaling force at a constant rate, and is scheduled during normal braking. The spring 11 regulates the upward movement of the elongated hole 10 of the push rod 4 so that the pedal ratio does not change until the pedal reaches a second predetermined pedaling force that is greater than the pedaling force in the range. Here, the second predetermined pedal effort is set assuming an emergency brake.
The emergency braking is that the driver senses a danger and depresses the brake pedal in a dash, and the pedaling force equivalent to the emergency braking is known to be about 50 kgf although it varies depending on the individual. It has a certain distance from the pedaling force in the range expected during normal braking. In other words, even if the biasing force of the spring 11 is somewhat uneven due to an assembly error or the like, the place where the pedal ratio becomes large does not enter the normal brake area.

As is apparent from the above description, in the first embodiment, the link 8 and the pins 7 and 9 correspond to the connecting means, and the elongated hole 10 and the spring 11 correspond to the pedal ratio varying means. Further, if the pedal ratio is constant, the reaction force from the master cylinder 6 and the pedal effort correspond substantially to each other. In the first embodiment, the pedal effort is observed by looking at the reaction force from the master cylinder 6.

Next, a second embodiment of the present invention will be described with reference to FIGS. Reference numeral 21 denotes a pedal arm, which has a pedal portion 22 at one end. An elongated hole 23 is provided at the other end, and a pin 24 is engaged with the elongated hole 23 to be supported by the vehicle body. The pedal arm 21 is rotatable around a pin 24. Reference numeral 25 denotes a push rod, which is connected to the pedal arm 21 by a pin 26 below the elongated hole 23 and transmits the pedal effort to the master cylinder 28 via the assisting device 27. The assisting device 27 and the master cylinder 28 have the same properties as the assisting device 5 and the master cylinder 6 in the first embodiment.
The description is omitted here. Reference numeral 29 denotes a pedal ratio variable device, which has a cylinder 30 and a piston 31 slidably fitted in the cylinder 30, and a spring 33 is arranged in a variable pressure chamber 32 formed by the cylinder 30 and the piston 31. Has been done. The spring 33 biases the piston 31 upward in the figure. A through hole 34 is provided at the lower end of the variable pressure chamber 32 in the figure, and the switching valve 35 selects communication between the variable pressure chamber 32 and a negative pressure source (not shown) and opening to the atmospheric pressure. The switching valve 35 is controlled by the control device 36. The controller 36 receives the pedal effort detected by the pedal effort sensor 37 provided in the pedal section. The pedal effort detected by the pedal effort sensor 37 is larger than the first predetermined pedal effort that the assisting device can assist the pedal effort at a constant rate, and is greater than the pedal effort in the range planned for normal braking. When the second predetermined pedaling force is set to a large value, the control device 36 switches the switching valve 35 so that the variable pressure chamber 32 communicates with a negative pressure source (not shown). Further, the piston 31 and the pin 24 are connected by a bar 38, and the pin 24 moves in the elongated hole 23 as the piston 31 moves up and down.

The operation of the variable pedal ratio brake pedal device configured as described above will be described. The variable pedal ratio brake pedal device is in the original position shown in FIG. When the pedal portion 22 is depressed from this state, the pedal arm 21 rotates about the pin 24. At this time, the variable pressure chamber 32 of the pedal ratio varying device 29 is opened to the atmospheric pressure, and the piston 31 is biased upward in the figure by the spring 33. That is, the pin 24 remains positioned at the upper end of the slot 23 in the figure. The pedal ratio at this time is measured from the center point L of the pin 24, which is the turning point of the pedal arm 21, to the push rod.
The center point M of the pin 26 that is the connection point of the pedal arm 21 of 25
Relative to the distance a ₅ up to the ratio b ₄ / a ₅ distance b ₄ from the center point L of which pin 24 a pivot point to the center point N of the pedal 22 of the pedal arm 21.

When the pedal portion 22 is further depressed, the pedal effort is larger than the first pedal effort that the assisting device can assist the pedal effort at a constant rate, and the pedal effort within a range that is planned during normal braking. When it is detected by the pedal force sensor 37 that the second predetermined pedal force, which is set to be larger than the predetermined pedal force, is detected, the control device 36 switches the switching valve 35 to move the variable pressure chamber 32 to a negative pressure source (not shown). Communicate. When the variable pressure chamber 32 communicates with a negative pressure source (not shown), the piston 31 slides downward in the figure,
As shown in FIG. 5, the pin 24 moves to the lower end of the slot 23 in the figure. The pedal ratio at this time is the distance from the center point O of the pin 24, which is the pivot point of the pedal arm 21, to the center point M of the pin 26, which is the connection point of the push rod 25 with the pedal arm 21.
Pin that is the pivot point of pedal arm 21 with respect to a ₆
Ratio of distance b ₅ from center point O of 24 to center point N of pedal section 22
b ₅ / a ₆ .

The pedal ratios of the two states will be compared. a ₆ = a ₅
−α, b ₅ = b ₄ −β. _{That, b 5 / a 6 -b 4} / a 5 = (b 4 -β) / (a 5 -α) -b 4 /
a ₅ a _{= (b 4 α-a 5} β) / a 5 (a 5 -α). Now consider a triangle LNO to compare the magnitudes of α and β. α = OL, β = LN-NO and α-β = OL-LN + NO, but since the sum of the two sides of the triangle is longer than the other one side, OL + NO>
LN, that is, OL-LN + NO> 0, and α-
β> 0. Also, b ₄ −a ₅ > 0,
Since b ₄ , a ₅ , α, and β are positive values, b ₄ α−
a ₅ β> 0. Further, since the pin 26 is on the lower side of the slot 23 in the figure, a ₅ -α> 0, and from the above, b ₅ / a ₆ -b ₄ / a ₅ > 0 jams, b ₅ / a ₆ >. b ₄ /
It is a ₅ , and it can be seen that the pedal ratio is large.

In the above-described variable pedal ratio brake pedal device, the pedal depression force detected by the pedal depression force sensor 37 is larger than the first predetermined pedal depression force with which the assisting device can assist the pedaling force at a constant rate, and The switching valve 35 cannot be switched until the second predetermined pedal force, which is set to be larger than the pedal pedal force in the range expected during normal braking, is reached.
Pedal ratio does not change. Here, the second predetermined pedal effort is set assuming an emergency brake. As mentioned above, the pedal effort equivalent to an emergency brake has been found to be about 50 kgf by experiments, and there is some gap from the pedal effort in the range planned for normal braking. In other words, even if there is some non-uniformity in the pedal effort for switching the switching valve 35 due to a detection error of the pedal effort sensor 37 or the like, the place where the pedal ratio becomes large does not enter the normal brake area.

As is apparent from the above description, in the second embodiment, the slot 23 and the pedal ratio changing device 29 correspond to the pedal ratio changing means.

[0030]

According to the present invention, the pedal ratio varying means allows
The pedal effort at a place where the pedal ratio is increased is greater than a predetermined pedal effort at which the assisting device can assist the pedal effort at a constant rate.
In addition, it is set to be larger than the pedaling force in the range expected during normal braking. In other words, since the place where the pedal ratio is increased is determined by the pedal effort, it is not affected by the change in pedal stroke. Therefore, even if the pedal stroke changes due to an assembly error of the brake pedal device, the pedal ratio does not increase during pedal operation within the range expected during normal braking, and the pedal ratio does not increase during normal braking. It will be constant.

Further, in the pedal ratio variable brake pedal device in which the portion where the pedal ratio becomes large is defined as the pedal stroke, the pedal must be depressed to the predetermined pedal stroke even if the assisting device fails. Requires a huge pedaling force. However,
According to the variable pedal ratio brake pedal device of the present invention, even if the assisting device fails, the pedal ratio increases when the pedal effort reaches the second predetermined pedal effort, and a larger braking effort is achieved with the same pedal effort. You can get it.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing a variable pedal ratio brake pedal device according to a first embodiment of the present invention in a non-operating state.

FIG. 2 is a cross-sectional view schematically showing a state where the pedal ratio variable brake pedal device according to the first embodiment of the present invention has been changed in pedal ratio.

FIG. 3 is a diagram schematically showing a force vector applied to a connecting member and pedal ratio varying means in the pedal ratio variable brake pedal device according to the first embodiment of the present invention.

FIG. 4 is a sectional view schematically showing a variable pedal ratio brake pedal device that is a second embodiment of the present invention in a non-operating state.

FIG. 5 is a schematic cross-sectional view of a second pedal ratio variable brake pedal device according to a second embodiment of the present invention in a state after the pedal ratio is changed.

FIG. 6 is an explanatory diagram regarding a pedal ratio.

FIG. 7 is a schematic cross-sectional view of a conventional pedal ratio variable brake pedal device in a non-operating state.

FIG. 8 is a cross-sectional view schematically showing a state of the conventional pedal ratio variable brake pedal device after the pedal ratio is changed.

FIG. 9 is a graph showing the relationship between pedal effort and pedal stroke.

[Explanation of symbols]

 1 ... Pedal arm 4 ... Push rod 5 ... Assist device 8 ... Link 10 ... Oblong hole 11 ... Spring 21 ... Pedal arm 23 ... Oblong hole 25 ... Push rod 27 ・ ・ ・ Assisting device 29 ・ ・ ・ Pedal ratio variable device

Claims (1)

[Claims] 1. A pedal arm having a pedal portion at one end and rotatably supported by a vehicle body at the other end, a push rod for transmitting a pedaling force applied to the pedal portion to a master cylinder, the push rod and the push rod. A connecting means for connecting the pedal arm and the pedal force is increased at a predetermined rate until the pedal force reaches a first predetermined pedal force, and thereafter the pedal force is increased to the first predetermined pedal force. An assisting device that increases the amount by a predetermined value and transmits the master cylinder to the master cylinder, and the pedaling force is larger than the first predetermined pedaling force, and is larger than the pedaling force in a range scheduled during normal braking. Only when the second predetermined pedal force, which is largely determined, is exceeded, the pedal arm is rotated from the rotation point of the pedal arm with respect to the distance from the rotation point of the pedal arm to the position of the connecting means on the pedal arm. The ratio of the distance to the center point of the section, the pedal ratio variable brake pedal apparatus characterized by having a pedal ratio varying means for the depression force is greater than the ratio of up to reaching said second predetermined pedal effort.