JP3542625B2 - Stick type parking brake - Google Patents

Description

[0001]
[Industrial applications]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parking brake of a motor vehicle, and more particularly to an improvement of a two-operation open stick-type parking brake.
[0002]
[Prior art]
A stick-type parking brake is one in which the brake is released by two different kinds of operations in order to prevent the brake from being released carelessly during parking, that is, two operations. An open type is known.
[0003]
The parking brake has a stem for pulling the brake wire and a fixed guide tube for guiding the linear movement of the stem, and a part of the upper surface of the stem is aligned with the axial direction. A series of rack teeth are provided, and the fixed guide tube is formed with a check pawl which engages with the rack teeth of the stem. When the brake is operated, the rack teeth of the stem and the fixed guide are fixed. The stem is held in a predetermined pulling position by engagement with the check pawl of the tube.
[0004]
Then, the handle of the stem is further pulled by a force greater than the reaction force of the brake wire to loosen the engagement between the check pawl and the rack teeth, and by rotating the handle, the rack teeth of the stem do not engage with the check pawl. The stem is rotated to the side line, then the stem is left to the brake reaction force and inserted forward.The brake wire is loosened to open the brake, and consists of a pin provided on the stem and a groove in the guide tube. The guide mechanism causes the stem to rotate back on the side line where the check pawl is present again at the final stage of opening the brake.
[0005]
However, even with such a two-operation type, for example, when the driver's knee accidentally hits the handle of the stem and the handle rotates, there is a possibility that the engagement between the check pawl and the rack teeth may be disengaged. There is a risk that the brakes will be opened carelessly. Therefore, as shown in, for example, Japanese Utility Model Application Laid-Open No. 63-24074 and Japanese Utility Model Application Laid-Open No. 63-24075, in recent years, a steering wheel that is able to idle with respect to a stem has been used.
[0006]
These include a return mechanism (consisting of an annular cam, an elastic body, or the like) that enables the idle rotation by attaching the handle to the stem (plunger) so that the handle can rotate freely, and returns the idled handle to an initial position with respect to the stem. In order to enable a twisting operation of the stem via the handle, there is provided an anti-spin device (comprising a slide key) which disables the idling of the handle.
[0007]
According to this configuration, as long as the anti-slip means is not operated, even if an external force is applied to the handle, the handle simply rotates idly with respect to the stem, and there is no danger of the brake being opened carelessly. When the external force stops, the handle returns to the original position by the return mechanism.
[0008]
[Problems to be solved by the invention]
As described above, the above-mentioned prior art is excellent in a two-operation open-type stick-type parking brake that reliably prevents the risk of inadvertent release of the brake. The possible range (the range of the idling angle that can be returned to the initial position by the return mechanism) is narrow, and improvement in this respect has been desired.
[0009]
That is, in the conventional brake described above, the direction of the force for returning the handle of the normal return mechanism to the initial position is reversed when the handle is twisted 90 degrees from the initial position. For this reason, in practice, the twist rotation angle of the handle must be 90 degrees or less in both directions, and the idling range is usually limited to 180 degrees or less.
[0010]
In addition, the above-mentioned conventional brake has a configuration in which the return mechanism and the slide key of the anti-spin device are provided so as to protrude in the radial direction at the connecting portion between the stem and the handle. Was.
[0011]
The present invention has been made in view of such a conventional problem, and it is possible to make the steering wheel idle, and furthermore, to make the possible idle rotation range of 180 degrees or more, and to further improve the appearance around the steering wheel. It is an object of the present invention to provide an operating mechanism for a cane-type parking brake that can be neatly cleaned.
[0012]
[Means for Solving the Problems]
The gist of the present invention to achieve such an object is as follows.
A stem capable of holding the brake cable in a pulled state, a handle rotatably attached to one end of the pull side of the stem, a return mechanism for returning the idle handle to an initial position with respect to the stem, and Anti-spin means for disabling idling of the handle so as to enable the twisting operation of the stem, and when the stem held via the handle is twisted with the anti-slip means activated, a brake In the walking stick type parking brake where the holding of the cable pulled state is released, the stem can be inserted and the brake cable can be loosened,
The return mechanism,
A cam plate slidable in a direction perpendicular to the axis of the stem in the handle, an urging means for urging the cam plate toward one end of the stem, and an urging means provided on one end of the stem. A peripheral cam that slides on the distal end surface of the cam plate and slides the cam plate in a direction against the urging means when the handle is twisted from the initial position and rotates relative to the stem. And
In the state where the handle is in the initial position, the contact position between the peripheral cam and the distal end surface of the cam plate is offset in the biasing direction of the biasing means with respect to the center line of the stem,
The handle comprises a handle body and a handle lid,
The base end of the handle body is open to the outside,
The handle lid closes the inside of the handle by being fitted into the opening,
Further, the stick is a stick-type parking brake, wherein the handle lid holds the biasing means and the cam plate in the handle when the handle lid is fitted into the opening.
[0013]
[Action]
In the stick type parking brake of the present invention, when the handle idles from an initial position (twist rotation with respect to the stem) due to some external force, the peripheral cam provided at one end of the stem rotates relative to the cam plate, and the handle is rotated. A cam plate slidably provided therein is slid against a biasing force. For this reason, until the direction of the torque generated between the stem and the cam plate (handle) is reversed by the urging force of the cam plate, the cam plate returns to the original contact state with the peripheral cam by the urging force until the external force disappears. Attempts to reverse the steering wheel and return to the initial position.
[0014]
The fact that the contact position between the peripheral cam and the tip end surface of the cam plate in the initial state is offset in the biasing direction of the cam plate with respect to the center line of the stem means that the direction of the torque due to the biasing force of the cam plate. Acts to make the angle of reversal larger than 90 degrees, and a free rotation range exceeding 180 degrees is obtained in both directions.
[0015]
【Example】
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
[0016]
As shown in FIG. 1, the stick type parking brake of this embodiment has a stem 10 for pulling a brake cable (not shown), and one end of the stem 10 can be twisted and rotated (slidable). , A return mechanism 30 for returning the idled handle 20 to its initial position with respect to the stem 10, and an anti-skid for disabling the handle 20 to allow the stem 10 to be twisted through the handle 20. Means 40.
[0017]
The stem 10 is supported by a guide tube (not shown) so as to be able to linearly move, and a predetermined pulling position is established by engagement of a rack tooth (not shown) partially provided on the surface thereof with a check pawl of the guide tube. Is held in the In FIG. 1, only one end of the stem 10 is shown, and the portion where the rack teeth are formed and the other end connected to the brake wire are omitted because they are the same as those in the well-known configuration.
[0018]
The handle 20 includes a handle main body 20a having a through hole through which the stem 10 is inserted on an axis, and a handle lid 20b screwed to the base end side of the handle main body 20a. The inner periphery of the distal end portion is slidably and rotatably fitted to the outer periphery of the base end side of the stem 10, so that the inner periphery of the stem 10 can freely rotate in the twist rotation direction.
[0019]
In this case, the base end side (handle portion) of the handle body 20a is generally rectangular as shown in FIG. 2, and the base end is open. A step portion 21 into which the handle lid 21 is fitted is formed at the inner edge of the base end side opening of the handle main body 20a, and furthermore, as shown in FIG. Opposing inner surfaces 22 are formed on both sides. A concave portion 23 into which a lower end of a spring 32 described later is fitted is formed in the lower portion of the inner surface of the handle main body 20a, and a distal end side of a push button 41 described later is formed below a through hole through which the stem 10 is inserted. This through hole 24 to be fitted is formed. A columnar projection 25 extending toward the inside of the through hole 24 is formed on the inner surface of the handle lid 20b on the axis of the through hole 24. The outer diameter of the cylindrical projection 25 is such that the inner surface on the distal end side of the cylindrical portion 41a of the push button 41 described later is slidably fitted.
[0020]
The return mechanism 30 includes a cam plate 31 fitted between the inner side surfaces 22 in the handle 20 and slidable in a direction perpendicular to the axis of the stem 10 (in this case, the longitudinal direction of the handle 20). A coil spring (biasing means) 32 for urging the stem 31 toward one end of the stem 10 and a peripheral cam 33 provided on one end of the stem 10 and slidably in contact with the tip end surface of the cam plate 31.
[0021]
The cam plate 31 is a substantially rectangular plate having a distal end surface 31a inclined at an angle θ2 as shown in FIGS. In the middle, a long hole 31c through which the columnar projection 25 penetrates, and a fitting hole 31d into which the distal end side of the tubular portion 41a of the push button 41 described later fits are formed.
[0022]
The fitting hole 31d has a diameter larger than the width of the long hole 31c, and is formed at a position where the distal end side of the tubular portion 41a of the push button 41 is fitted when the cam plate 31 is at the initial position. The long hole 31c is set to have such a size that the cylindrical projection 25 is released for the entire sliding stroke of the cam plate 31. Here, the initial position of the cam plate 31 refers to a sliding position of the cam plate 31 in a state where a plane portion 33a, which will be described later, of the peripheral cam 33 is in close contact with the tip surface 31a of the cam plate 31 in parallel. The twist rotation position of the handle 20 with respect to the stem 10 in the state is referred to as an initial position of the handle 20 in the following description.
[0023]
The peripheral cam 33 is fixed to the end of the stem 10 by a driving pin or the like, and is formed so as to partially cut off the end surface of the cylindrical member 15 that rotates relative to the handle 20 together with the stem 10. As shown in FIG. 4, it is composed of a flat portion 33a, a small-diameter circular portion 33b, and a large-diameter circular portion 33c.
[0024]
Here, the flat portion 33a is offset from the axis center line of the stem 10 by a dimension b. The large-diameter arc-shaped portion 33c is an arc centered on the axis center line of the stem 10, and the small-diameter arc-shaped portion 33b is separated from the axis center line of the stem 10 by a distance L in the direction of the angle θ1 (hereinafter, referred to as a point). The flat part 33a and the large-diameter circular part 33c are smoothly connected by an arc having a radius r centered on the cam reference point K). Here, the angle θ1 is an angle from a reference line intersecting the axis center line of the stem 10 and orthogonal to the plane portion 33a, and the peripheral cam 33 is symmetric with respect to this reference line.
[0025]
As shown in FIG. 3, the idling prevention means 40 is slidably mounted in the through hole 24 of the handle lid 20b, and the tip end side is fitted into the fitting hole 31d of the cam plate 31 to move the cam plate 31 to the initial position. And a return coil spring 42 for pushing the push button 41 back to a position (open position) away from the cam plate 31 at the tip.
[0026]
The push button 41 includes a cylindrical portion 41 a inserted into the through hole 24, and a button portion 41 b attached to the proximal end of the cylindrical portion 41 a and protruding toward the front side of the handle 20. The push button 41 is configured to be held at the open position by receiving the urging force of the return coil spring 42 by the retaining ring 43 previously loaded in the deep step portion 24a in the through hole 24. The fitting of the retaining ring 43 to the outer periphery of the cylindrical portion 41a is performed by inserting the push button 41 into the through hole 24 and fitting the distal end side of the cylindrical portion 41a to the outer periphery of the cylindrical projection 25 of the handle cover 20b. This is performed by enlarging the diameter. The return coil spring 42 is inserted in a compressed state between the inner surface of the button portion 41b and the distal end surface of the columnar projection 25. When the push button 41 is attached, the return coil spring 42 is previously inserted into the cylindrical portion 41a. It is attached by leaving.
[0027]
Except for the button portion 41b of the push button 41, the entire handle 20 and the like are finally covered with the resin material 50 by cast-in molding as shown by a two-dot chain line in FIGS. The mounting of the push button 41 can be performed after this insert molding.
[0028]
Next, the operation will be described.
In the stick-type parking brake, when the handle 20 idles from an initial position (twist rotation with respect to the stem 10) due to some external force, a peripheral cam 33 provided on one end side of the stem 10 as shown in FIG. The cam plate 31 rotates relative to the handle 31 and slides the cam plate 31 slidably provided in the handle 20 against the urging force of the spring 32. Therefore, as long as the direction of the torque generated between the stem 10 and the cam plate 31 (the handle 20) is not reversed by the urging force of the spring 32, the cam plate 31 is moved against the peripheral cam 33 by the urging force of the spring 32 unless the external force is lost. An attempt is made to return to the original contact state, and as a result, the handle 20 reversely spins and returns to the initial position.
[0029]
Then, the contact position between the peripheral cam 33 and the tip end surface 31a of the cam plate 31 in the initial state shown in FIGS. 2 and 4 is offset by the dimension b in the urging direction of the cam plate 31 with respect to the center line of the stem 10. This means that the angle at which the direction of the torque is reversed by the urging force of the cam plate 31 is made larger than 90 degrees, and a free rotation range exceeding 180 degrees is obtained in both directions.
[0030]
That is, in consideration of the condition in which the handle 20 can return to the initial position after idling in the state of FIG. 4, the torque due to the urging forces F1 and F2 of the coil spring 32 is smaller than the contact friction force f between the peripheral cam 33 and the cam plate 31. It is necessary to be large, and it is necessary to satisfy F1.a-F2.b> f.b. In this equation, the following relational expressions are substituted: a = L · sin (θ1 + θ2), b = L · cos θ1−r, f = F1 · cos θ2 · μ, F2 = F1 · sin θ2, and neglecting r Then, μ <tan θ1 is obtained (μ is a friction coefficient). Since μ is usually about 0.15, specifically, θ1> 8.53 degrees. That is, when the peripheral cam 33 is relatively rotated with respect to the cam plate 31, the range in which the peripheral cam 33 does not return to the original position (that is, the range in which the idle cam cannot rotate) is 17.06 degrees in both directions.
[0031]
Therefore, considering the angular displacement of the reference point K of the peripheral cam 33 as shown in FIG. 6, the non-spinning range of 17.06 degrees is determined by the reference line of the peripheral cam 33 (the center of the peripheral cam 33 and the cam plate 31). (A line perpendicular to the inclined front end surface of the peripheral cam 33), an angle θ4 = 2 · θ1 (shown in FIG. 4) based on the size of the peripheral cam 33 itself and a margin angle θ5 (see FIG. 6), a large free-wheeling range of about 110 degrees on one side is practically obtained. If the offset b = 0, the angle θ4 becomes close to 180 degrees, so that the idling range is smaller than 90 degrees.
[0032]
Accordingly, with the above-described brake device, even if an external force is applied to the handle 20 during the brake operation, the handle 20 idles and the brake is not released carelessly. Moreover, as shown in FIG. If the angle is within the range of 220 degrees, the coil spring 32 automatically returns to the initial position by the urging force. Therefore, it is not necessary to return the handle 20 to the original position by hand as compared with the related art, which is convenient.
[0033]
In the brake device, since the return mechanism 30 and the anti-spin device 40 are mainly provided inside the handle 20, the connecting portion between the handle and the stem is provided with a configuration corresponding thereto, and the connecting portion is provided. Also, as compared with a conventional brake device that protrudes in the radial direction, there is also an effect that the appearance is clear and the appearance is improved.
[0034]
It should be noted that the present invention is not limited to the above-described embodiment, and may have various aspects. For example, as shown in FIG. 8, the tip surface of the cam plate 31 may be a plane perpendicular to the sliding direction. Even in this case, a high-range idling and returning operation can be performed by the relative operation of the peripheral cam 33 and the cam plate 31 as shown in FIG. The inclined front end surface of the cam plate 31 has an effect of stabilizing the handle rotation position at the initial position.
[0035]
【The invention's effect】
With the stick type parking brake according to the present invention, the brake is not released carelessly even when an external force is applied to the handle during the brake operation, and the idling angle in a high range exceeding 180 degrees. Automatically returns to the initial position, so that there is no need to return the steering wheel to the original position manually as compared with the related art, which is convenient.
[Brief description of the drawings]
FIG. 1 is a side view showing a main part of a walking stick type parking brake according to an embodiment of the present invention.
FIG. 2 is a front view showing a stick-type parking brake according to one embodiment of the present invention in a state where a handle lid is removed.
FIG. 3 is a sectional view taken along line AA in FIG.
FIG. 4 is a diagram schematically showing a return mechanism in a walking stick type parking brake according to one embodiment of the present invention.
FIG. 5 is a diagram showing an operation of a return mechanism in the walking stick type parking brake according to one embodiment of the present invention.
FIG. 6 is a diagram showing a positional relationship between a peripheral cam and a cam plate for explaining a free rotation range of a handle in a walking stick type parking brake according to an embodiment of the present invention.
FIG. 7 is a view showing an idling range of a handle in a walking stick type parking brake according to an embodiment of the present invention.
FIG. 8 is a view schematically showing a return mechanism in a walking stick type parking brake according to another embodiment of the present invention.
FIG. 9 is a view showing the operation of a return mechanism in a walking stick type parking brake according to another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Stem 20 ... Handle 30 ... Return mechanism 31 ... Cam plate 32 ... Biasing means 33 ... Peripheral cam 40 ... Idling prevention means

Claims (1)

A stem capable of holding the brake cable in a pulled state, a handle rotatably attached to one end of the pull side of the stem, a return mechanism for returning the idle handle to an initial position with respect to the stem, and Anti-spin means for disabling the handle to allow the stem to twist, and twisting the stem held via the handle in a state where the anti-slip means is actuated. In the walking stick type parking brake where the holding of the cable pulled state is released, the stem can be inserted and the brake cable can be loosened,
The return mechanism,
A cam plate slidable in a direction perpendicular to the axis of the stem in the handle, an urging means for urging the cam plate toward one end of the stem, and an urging means provided on one end of the stem. A peripheral cam that slides on the distal end surface of the cam plate and slides the cam plate in a direction against the urging means when the handle is twisted from the initial position and rotates relative to the stem. And
In the state where the handle is in the initial position, the contact position between the peripheral cam and the distal end surface of the cam plate is offset in the biasing direction of the biasing means with respect to the center line of the stem,
The handle comprises a handle body and a handle lid,
The base end of the handle body is open to the outside,
The handle lid closes the inside of the handle by being fitted into the opening,
Further, the stick type parking brake, wherein the handle lid holds the urging means and the cam plate in the handle when the handle lid is fitted into the opening.

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