JP2004017918A - Lever ratio variable pedal device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance a flexibility of a setup of a lever ratio characteristic and simply constitute it at a low cost with a small number of parts. <P>SOLUTION: Since a cam mechanism 26 consisting of a first engaging part 32 and a second engaging part 34 of an approximately circular arc shape which makes the link connecting points P1, P2 be the center, is provided as a lever ratio variable mechanism, the same kind of the lever ratio characteristic is obtained when the link connecting points P1, P2 are connected by the link. The link and the connecting pin or the like are not necessary and simply constituted with a low cost by decreasing a number of parts. In addition, only by deforming the basic shape of the first engaging part 32 and the second engaging part 34, that is, the circular arc shape which makes the link connecting points P1, P2 be the center, so that the distance (radii R1, r1) from the link connecting points P1, P2 may change partially, the lever ratio characteristic is variable finely partially, and the flexibility of the setup of the lever ratio characteristic is enhanced. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a pedal device such as a brake pedal or an accelerator pedal, and more particularly to a lever ratio variable pedal device which has a high degree of freedom in setting input / output characteristics (lever ratio characteristics) during a stepping operation and has excellent operability. .
[0002]
[Prior art]
(A) an operation pedal rotatably disposed around a first axis; and (b) a lever rotatably disposed around a second axis substantially parallel to the first axis. (C) mechanically pressing or pulling the intermediate member with the rotation of the intermediate member, the intermediate member being rotated about the second axis in conjunction with the depression operation of the operation pedal via the variable ratio mechanism; (D) a lever ratio variable pedal device that has a lever ratio variable mechanism and obtains predetermined lever ratio characteristics. The pedal device described in Japanese Patent Application Laid-Open No. 7-205776 is an example of such a device, in which an operation pedal and an intermediate member are connected by a link, and a lever ratio is changed according to a pedal stroke (a stepping amount of the operation pedal). The lever ratio characteristic can be changed according to the length and the connection position of the link functioning as a lever ratio variable mechanism. The lever ratio is a ratio between the amount of operation of the operation pedal and the amount of movement of the output member. As the lever ratio increases, the output with respect to an input (pedal force) increases. The lever ratio characteristic is a change characteristic of the lever ratio with respect to the pedal stroke, and corresponds to the input / output characteristic at the time of the depression operation.
[0003]
[Problems to be solved by the invention]
However, in such a conventional lever ratio variable pedal device, it is difficult to finely adjust the lever ratio characteristics because the lever ratio characteristics are determined by the length of the link and the connection position. In addition, since the operation pedal and the intermediate member are connected by the link, a connecting pin and the like are required in addition to the link, so that the number of parts is increased, and there is a problem that the manufacturing cost is increased.
[0004]
The present invention has been made in view of the above circumstances, and aims to further increase the degree of freedom in setting the lever ratio characteristics and to reduce the number of parts so that the configuration can be simplified and inexpensively. Is to do.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a first aspect of the present invention provides (a) an operation pedal arranged to be rotatable around a first axis, and (b) a second axis substantially parallel to the first axis. An intermediate member rotatably arranged around the second axis, which is interlocked with a stepping operation of the operation pedal via a lever ratio variable mechanism, and (c) the intermediate member; (D) a lever ratio variable pedal device that has a predetermined lever ratio characteristic obtained by the lever ratio variable mechanism. The lever ratio variable mechanism includes a cam including a first engagement portion provided on the operation pedal side and a second engagement portion provided on the intermediate member side so as to be engaged with the first engagement portion. (F) the first engagement portion and the second engagement portion Characterized in that it comprises an arc in contact with each other as a basic shape around preset the link joining point, respectively.
[0006]
According to a second aspect, in the lever ratio variable pedal device according to the first aspect, at least one of the first engagement portion and the second engagement portion connects the link connection point with a link having a fixed length. The distance from the link connection point to the basic shape is partially changed so as to partially change the lever ratio based on the ratio characteristic.
[0007]
A third invention is the lever ratio variable pedal device of the second invention, wherein (a) the lever ratio characteristic is such that the lever ratio is maximized at an intermediate position of a pedal stroke, and (b) the first engagement portion and the The basic shape of the second engagement portion is a circular arc that is in contact with each other around the link connection point at a pedal stroke position where the lever ratio is maximized.
[0008]
A fourth invention is the lever ratio variable pedal device of the second invention or the third invention, wherein each of the first engagement portion and the second engagement portion is a distance from the link connection point with respect to the basic shape. Is partially changed.
[0009]
【The invention's effect】
That is, in the present invention, instead of providing a link, a cam mechanism including a first engagement portion and a second engagement portion having a basic shape of an arc that is in contact with each other around a link connection point is provided as a lever ratio variable mechanism. Basically, the same lever ratio characteristics as in the case of connecting with a link can be obtained, but the link and the connecting pin are unnecessary, the number of parts is reduced, and the structure is simple and inexpensive. In addition, the levers are formed by merely deforming the basic shapes of the first engagement portion and the second engagement portion, that is, the arc shape centered on the link connection point so that the distance from the link connection point is partially changed. The ratio characteristics can be partially and finely changed, and the degree of freedom in setting the lever ratio characteristics is further increased.
[0010]
In the second aspect, at least one of the first engagement portion and the second engagement portion partially changes the lever ratio based on a lever ratio characteristic when the link connection point is connected by a link having a fixed length. Since the distance from the link connection point is partially changed so as to cause the desired lever ratio characteristic to be easily obtained.
[0011]
In the third aspect, the lever ratio is maximized at an intermediate position of the pedal stroke, and the arcs that are in contact with each other around the link connection point at the pedal stroke position where the lever ratio is maximized are the first engagement portion and the second engagement portion. Since the basic shape of the engaging portion is determined, a necessary lever ratio is secured at a predetermined pedal stroke position (intermediate position), and the lever ratio at the front and rear positions is adjusted to easily obtain a desired lever ratio characteristic. Can be obtained.
[0012]
In the fourth aspect, the distance between the first engagement portion and the second engagement portion from the link connection point is partially changed with respect to the basic shape, so that the lever ratio characteristic is more finely adjusted. And the degree of freedom in setting the lever ratio characteristic is further increased.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
The variable lever ratio pedal device of the present invention is suitably applied to a brake pedal device for a service brake of a vehicle, but is a pedal device for other vehicles such as a parking brake pedal, an accelerator pedal, a clutch pedal, or a device other than the vehicle. Of the present invention.
[0014]
The first engagement portion and the second engagement portion constituting the cam mechanism are provided, for example, on the operation pedal and the intermediate member, and the third member is interposed between the operation pedal and the intermediate member. In this case, the first engaging portion and the second engaging portion may be provided at the engaging portion between the operation pedal and the third member or the engaging portion between the third member and the intermediate member.
[0015]
For example, the first engagement portion and the second engagement portion are provided integrally with the operation pedal and the intermediate member, respectively, and are configured to be in sliding contact with each other. One of the first engagement portion and the second engagement portion is centered on the link connection point. It is also possible to use a roller which has a cylindrical shape and is rotatable around its link connection point.
[0016]
In the second invention, at least one of the first engagement portion and the second engagement portion is partially deformed with respect to the basic shape. Each of the second engagement portions may have a basic shape, that is, an arc centered on the link connection point. In other words, a case where the same lever ratio characteristic as that obtained when the link connection points are connected by the link may be obtained.
[0017]
In the third invention, the lever ratio is maximized at an intermediate position of the pedal stroke, and the arcs that are in contact with each other around the link connection point at the pedal stroke position where the lever ratio is maximized are the first engagement portion and the second engagement portion. Although the basic shape of the joint portion is determined, the basic shape of the first engagement portion and the second engagement portion may be determined in a state where the operation pedal is held at the original position before the depression operation. Various modes are possible, for example, the lever ratio may simply be raised or lowered with an increase in the pedal stroke.
[0018]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a partially cutaway front view showing a brake pedal device 10 for a service brake of a vehicle, which is one embodiment of a variable lever ratio pedal device of the present invention. The brake pedal device 10 includes an operation pedal 18 rotatably disposed around an axis of a substantially horizontal first support shaft 16 provided on a bracket 14 integrally fixed to the vehicle body 12, An intermediate member 22 disposed on the bracket 14 so as to be rotatable about the axis of the second support shaft 20 parallel to the first support shaft 16, and the operation pedal 18 is provided with a pedal pad provided at a lower end thereof. 24 is rotated clockwise in the figure by being depressed by the driver. The operation pedal 18 and the intermediate member 22 are engaged via a cam mechanism 26 functioning as a lever ratio variable mechanism, and the intermediate member 22 moves leftward of the second support shaft 20 in conjunction with the depression operation of the operation pedal 18. The lever 30 is turned around, and the rod 30 of the brake booster connected via the clevis 28 is mechanically pressed to the left in the figure, and the push rod of the master cylinder (not shown) is pushed in to generate brake hydraulic pressure. The rod 30 is biased so as to protrude from the brake booster, and the biasing force causes the intermediate member 22 to return to the clockwise direction of the second support shaft 20 and rotate. It is rotated counterclockwise and held at the original position shown in FIG. The engagement state of the operation pedal 18 with the intermediate member 22 is maintained by a spring or the like (not shown). The axis of the first support shaft 16 corresponds to the first axis, the axis of the second support shaft 20 corresponds to the second axis, and the rod 30 corresponds to the output member.
[0019]
The cam mechanism 26 includes a first engaging portion 32 provided integrally with the operation pedal 18, and a second engaging portion provided integrally with the intermediate member 22 so as to be engaged with the first engaging portion 32. As shown in the enlarged view of FIG. 2, the first engagement portion 32 and the second engagement portion 34 are substantially formed around predetermined link connection points P1 and P2, respectively. It has an arc shape. As shown in FIG. 3, the link connecting points P1 and P2 provide a predetermined lever ratio characteristic when the operation pedal 18 and the intermediate member 22 are connected by a link 40 having a predetermined length instead of the cam mechanism 26. At the point position, in the present embodiment, the lever ratio characteristic is determined so that the lever ratio becomes maximum at the middle position of the pedal stroke as shown by the solid line in FIG. Therefore, the distance L1 between the connection points in FIG. 2A is set to the length of the link 40 in FIG. 3, and the first engagement portion 32 and the second engagement portion 34 are connected to the link connection points P1 and P2, respectively. And the lever ratio characteristic shown by the solid line in FIG. 4 can be obtained similarly to the pedal device 42 in FIG. FIG. 2A shows a state in which the operation pedal 18 is held at the original position, and FIG. 2B shows a state in which the stepping operation is performed. However, the first engagement portion 32 and the second engagement portion 34 are linked to each other. If the shape is a perfect arc centered on the points P1 and P2, R1 = R2, r1 = r2, and L1 = L2 throughout the pedal stroke.
[0020]
On the other hand, for at least one of the first engagement portion 32 and the second engagement portion 34, an arc having a radius R1, r1 centered on the link connection points P1, P2 is used as a basic shape, and the link is formed from the link connection points P1, P2. When the distance R1, r1 is partially changed, the lever ratio is partially changed at a predetermined position of the pedal stroke, as shown by a dashed line or a broken line, based on the lever ratio characteristic shown by a solid line in FIG. Can be changed. In this embodiment, when at least one of the radii R1 and r1 is increased to increase the distance L1 between connection points, the lever ratio increases. When at least one of the radii R1 and r1 is reduced to decrease the distance L1 between connection points, the lever ratio increases. Since the ratio becomes small, at least one of the radii R1 and r1 is smoothly increased or decreased to change the distance L1 between the connection points, thereby partially changing the lever ratio characteristic shown by the solid line in FIG. Excellent lever ratio characteristics can be obtained. In this case, the radii R1 and r1 of both the first engagement portion 32 and the second engagement 34 can be partially changed, but only one of them may be changed. 5 and the broken line show the case where only the radius R1 of the first engagement portion 32 is partially changed. The dashed line and the broken line in FIG. 5 show the radii R1, r1 of both the first engagement portion 32 and the second engagement 34. Is partially changed. The reference lever ratio characteristics and the change in the lever ratio due to the increase or decrease of the connection point distance L1 are obtained by conducting experiments using a plurality of links 40 having different lengths or by calculating according to a predetermined arithmetic expression. You can ask.
[0021]
The lever ratio characteristic indicated by the dashed line in FIG. 4 is such that, at the pedal stroke position where the lever ratio is maximized, arcs that are in contact with each other around the link connection points P1 and P2 are set as the basic shapes of the engagement portions 32 and 34, Before and after the pedal stroke at which the maximum lever ratio is obtained, the radius R1 of the first engagement portion 32 is smoothly increased so that the lever ratio becomes larger than the reference lever ratio characteristic shown by the solid line, and the distance between the connection points is increased. This is the case where L1 is increased. The lever ratio characteristic indicated by the broken line is such that, at the pedal stroke position where the lever ratio is maximized, the arcs that are in contact with each other around the link connection points P1 and P2 are set as the basic shapes of the engagement portions 32 and 34, and Before and after the pedal stroke at which the maximum lever ratio is obtained, the radius R1 of the first engaging portion 32 is smoothly reduced so that the lever ratio becomes smaller than the reference lever ratio characteristic shown by the solid line, and the distance L1 between the connection points is reduced. Is smaller.
[0022]
On the other hand, the lever ratio characteristics indicated by the one-dot chain line and the broken line in FIG. 5 are, as compared with the lever ratio characteristics indicated by the one-dot chain line and the broken line in FIG. In this case, the radius r1 of the second engagement portion 34 is smoothly increased to increase the distance L1 between the connection points so that the lever ratio is increased. The lever ratio characteristics shown by the solid line in FIG. 5 are the same as the lever ratio characteristics shown by the solid line in FIG. 4, and are shown for comparison.
[0023]
As described above, the brake pedal device 10 of the present embodiment includes the first engagement portion 32 and the second engagement portion 34 having a substantially arc shape centered on the link connection points P1 and P2 instead of the link 40 shown in FIG. Is provided as a lever ratio variable mechanism, so that basically the same lever ratio characteristics as in the case of being connected by the link 40 can be obtained, but the number of parts is reduced because the link 40 and the connecting pin are not required, It is simpler and cheaper than the pedal device 42 having the link 40.
[0024]
In addition, the basic shapes of the first engagement portion 32 and the second engagement portion 34, that is, the arc shapes centered on the link connection points P1 and P2 are partially changed from the link connection points P1 and P2 (radius R1). , R1), the lever ratio characteristics can be partially and finely changed simply by deforming them so that the lever ratio characteristics can be set more flexibly.
[0025]
Further, the lever ratio is partially changed based on the lever ratio characteristics when the link connection points P1 and P2 are connected by a link 40 having a fixed length, that is, the lever ratio characteristics indicated by solid lines in FIGS. Thus, a desired lever ratio characteristic can be easily obtained only by partially changing the distances (radius R1, r1) from the link connection points P1, P2.
[0026]
In addition, the lever ratio is maximized at an intermediate position of the pedal stroke, and arcs that are in contact with each other around the link connection points P1 and P2 at the pedal stroke position where the lever ratio is maximized are formed by the first engagement portion 32 and the second engagement portion. Since the basic shape of the engaging portion 34 is determined, a necessary and sufficient lever ratio is secured at a predetermined pedal stroke position (intermediate position), and the lever ratio at the front and rear positions is adjusted to obtain a desired lever ratio characteristic. Can be easily obtained.
[0027]
If the distances (radii R1, r1) from the link connection points P1, P2 to the basic shapes of the first engagement portion 32 and the second engagement portion 34 are respectively partially changed, for example, FIG. As shown by a dashed line and a broken line, the lever ratio characteristic can be more finely adjusted, and the degree of freedom in setting the lever ratio characteristic is further increased.
[0028]
Although the embodiment of the present invention has been described in detail with reference to the drawings, this is merely an embodiment, and the present invention is embodied in various modified and improved forms based on the knowledge of those skilled in the art. Can be.
[Brief description of the drawings]
FIG. 1 is a partially cutaway front view showing an embodiment of a brake pedal device to which the present invention is applied.
FIGS. 2A and 2B are enlarged views showing a cam mechanism of the brake pedal device of FIG. 1, wherein FIG. 2A shows a state in which the operation pedal is held at an original position, and FIG. 2B shows a state in which the operation pedal is depressed; .
FIG. 3 is a front view of a case where the cam mechanism of FIG. 2 is connected by a link instead of the cam mechanism.
FIG. 4 is a diagram illustrating an example of a lever ratio characteristic when one of a first engaging portion and a second engaging portion constituting the cam mechanism of FIG. 2 is partially deformed.
FIG. 5 is a diagram illustrating an example of a lever ratio characteristic when both the first engagement portion and the second engagement portion constituting the cam mechanism of FIG. 2 are partially deformed.
[Explanation of symbols]
10: Brake pedal device (lever ratio variable pedal device) 16: First support shaft (first shaft center) 18: Operation pedal 20: Second support shaft (second shaft center) 22: Intermediate member 26: Cam mechanism (lever) Ratio variable mechanism) 30: rod (output member) 32: first engagement portion 34: second engagement portion P1, P2: link connection point R1, r1: radius

Claims (4)

An operation pedal rotatably arranged around the first axis;
The control unit is rotatably disposed about a second axis substantially parallel to the first axis, and rotates about the second axis in conjunction with a depression operation of the operation pedal via a lever ratio variable mechanism. An intermediate member to be moved;
An output member that is mechanically pressed or pulled with the rotation of the intermediate member,
In the lever ratio variable pedal device having a predetermined lever ratio characteristic by the lever ratio variable mechanism,
The lever ratio variable mechanism includes a first engagement portion provided on the operation pedal side, and a second engagement portion provided on the intermediate member side so as to be engaged with the first engagement portion. With the cam mechanism,
The lever ratio variable pedal device, wherein the first engagement portion and the second engagement portion each have, as a basic shape, arcs that are in contact with each other around a preset link connection point. At least one of the first engagement portion and the second engagement portion is configured to partially change a lever ratio based on a lever ratio characteristic when the link connection point is connected by a link of a fixed length. The lever ratio variable pedal device according to claim 1, wherein a distance from the link connection point to the basic shape is partially changed. The lever ratio characteristic shows that the lever ratio is maximized at an intermediate position of the pedal stroke,
The basic shape of the first engagement portion and the second engagement portion are arcs that are in contact with each other about the link connection point at a pedal stroke position where the lever ratio is maximized. The variable lever ratio pedal device as described in the above. The distance between the first connection portion and the link connection point of the first engagement portion and the second engagement portion is partially changed with respect to the basic shape. The variable lever ratio pedal device as described in the above.

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