Accelerator device

An accelerator pedal is supported by a support member. A biasing member biases the accelerator pedal to the full close position. A resistance application unit increases a frictional force to increase a rotational resistance applied to the accelerator pedal, as a rotation angle of the accelerator pedal increases. A slidable portion is mounted to the support member and slidable on the accelerator pedal. A first latch portion and a second latch portion define an interspace therebetween in a rotational direction. The support member includes a rotation restrictive projection fitted between the first latch portion and the second latch portion.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on reference Japanese Patent Application No. 2013-78713 filed on Apr. 4, 2013, the disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to an accelerator device.

BACKGROUND

A known accelerator device has an electronic configuration to cause a sensor to detect a depression quantity of an accelerator pedal and to transmit an electric signal, which represents the depression quantity, to an electronic control unit. Patent Document 1 discloses an accelerator device. The accelerator device includes a frictional member, which is equipped between a pedal arm of an accelerator pedal and a spring rotor. The frictional member has an annular portion and a rotation restrictive projected portion. The annular portion is slidable relative to the pedal arm. The rotation restrictive projected portion is projected from the annular portion outward in the radial direction. The projected portion has a tip end, which is fitted to a recessed portion formed in a wall of a housing to restrict relative displacement in the rotational direction.

Publication of Unexamined Japanese Patent Application No. 2006-032712 It is noted that, each of components of the accelerator device increases and decreases in size with change in temperature of an operation environment. In general, the frictional member is formed of a resin material, which is relatively soft, and the housing is formed of a resin material, which is relatively hard. Further in general, the relatively soft resin material has a coefficient of linear expansion greater than a coefficient of linear expansion of the relatively hard resin material. Therefore, the projected portion of the frictional member expands under an operation environment at high temperature, such that the projected portion is urged onto the wall of the housing. After the projected portion is continually urged onto the wall of the housing, the projected portion causes a creep strain. Consequently, the projected portion of the frictional member reduces in size at a contact portion at which the projected portion is in contact with the wall of the housing. As a result, when the operation environment decreases to a relatively low temperature, a gap may be formed between the projected portion of the frictional member and the wall of the housing. Thus, even when a driver depresses the accelerator pedal, depression force may not appropriately increase in the beginning of the depression due to the gap. Consequently, the formation of the gap may impair an operational feeling of the accelerator pedal.

SUMMARY

It is an object of the present disclosure to produce an accelerator device, which is configured to maintain an operational feeling of an accelerator pedal.

According to an aspect of the present disclosure, an accelerator device comprises a support member attachable to a vehicle body. The accelerator device further comprises an accelerator pedal supported by the support member and rotatable from a full close position to a full open position. The accelerator device further comprises a biasing member configured to bias the accelerator pedal to the full close position. The accelerator device further comprises a frictional member located between a first member and a second member, the frictional member mounted to the first member and slidable on the second member. The first member is one of the support member and the accelerator pedal. The second member is an other of the support member and the accelerator pedal. The accelerator device further comprises a resistance application unit configured, as a rotation angle of the accelerator pedal increases from the full close position, to increase a frictional force between the second member and the frictional member and to increase a rotational resistance applied from the frictional member to the accelerator pedal. The frictional member includes a slidable portion, a first latch portion, and a second latch portion. The slidable portion is slidable on the second member. The first latch portion and the second latch portion define an interspace therebetween in a rotational direction.

The first member includes a rotation restrictive projection fitted between the first latch portion and the second latch portion.

DETAILED DESCRIPTION

As follows, embodiments of the present disclosure will be described with reference to drawings.

First Embodiment

FIG. 1shows an accelerator device according to a first embodiment of the present disclosure. An accelerator device10is an input device operated by a driver in order to control an operating state of an engine of a vehicle (one shown). The accelerator device10has an electronic configuration to transmit an electric signal to an electronic control unit (not shown). The electric signal represents a depression quantity of an accelerator pedal40. The electronic control unit manipulates a throttle valve according to an electric signal, which is transmitted from the accelerator device10.

First, a configuration of the accelerator device10will be described with reference toFIG. 1andFIG. 2.FIG. 1andFIG. 2show a positional relation of the accelerator device10mounted to a vehicle body100. In the following description, the top and bottom direction of the accelerator device10, which is mounted to the vehicle body100, corresponds to a vertical direction.

The accelerator device10includes a housing (support member)20, a shaft25, a rotational angle sensor30, the accelerator pedal40, a first spring60, a second spring61, a first frictional member65, and a second frictional member66. The housing20may function as a support member.

The housing20is a tubular member extended in the vertical direction. The housing20is integrally formed with mountable portions21and an open-side stopper22. The mountable portions21may be fixed to the vehicle body100by using fasteners such as bolts. The open-side stopper22restricts rotation of the accelerator pedal40in an accelerator open direction at a full open position. The shaft25is rotatably supported by the housing20at both ends. The shaft25has an accommodation hole26at one end. The accommodation hole26is for accommodating a detection unit of the rotational angle sensor30.

The rotational angle sensor30includes a magnetism detection element31and magnets32and33. The magnetism detection element31is equipped to a center of the shaft25and located in the accommodation hole26. The magnets32and33are fixed to a wall defining the accommodation hole26. The magnets32and33interpose the magnetism detection element31therebetween. A density of magnetic flux, which passes through the magnetism detection element31, changes with rotation of the shaft25. The magnetism detection element31sends an external electronic control unit an electric signal according to the density of the magnetic flux passing therethrough.

The accelerator pedal40includes an operational member41and a restoration member51. The operational member41includes a pedal rotor42, a coupling portion43, a close-side stopper44, a lever45, and a pad46. The pedal rotor42is fitted to the shaft25. The coupling portion43is projected from the pedal rotor42downward. The close-side stopper44restricts rotation of the accelerator pedal40in an accelerator close direction at a full close position. The lever45is connected with the coupling portion43. The pad46is fixed to a tip end of the lever45. The pedal rotor42has multiple first inclined teeth47. Each of the first inclined teeth47protrudes toward the return rotor52of the restoration member51increasingly in the accelerator close direction.

The restoration member51includes a return rotor52and a spring latch portion53. The return rotor52is fitted to the shaft25such that the return rotor52is rotatable relative to the shaft25. The spring latch portion53is extended from the return rotor52toward an upper portion of an internal space of the housing20. The return rotor52has multiple second inclined teeth54. Each of the second inclined teeth54is projected toward the pedal rotor42increasingly in the accelerator open direction.

A spring holder55is attached to the spring latch portion53of the restoration member51. The first spring60and the second spring61are equipped between the spring holder55and the housing20to bias the restoration member51in the accelerator close direction. The first spring60and the second spring61may function as a biasing member. The first frictional member65is equipped between the pedal rotor42and the housing20. The second frictional member66is equipped between the return rotor52and the housing20.

The operational member41receives a torque, and the torque is transmitted to the return rotor52via the first inclined tooth47and the second inclined tooth54in this order. At this time, the first inclined tooth47and the second inclined tooth54apply a biasing force to the pedal rotor42and the return rotor52, such that the pedal rotor42and the return rotor52are separated from each other in an axial direction. The first inclined tooth47and the second inclined tooth54apply the biasing force increasingly as a rotation angle increases from the full close position of the operational member41. Thus, at this time, the first frictional member65and the second frictional member66are in friction contact with the housing20to bias a rotational resistance to the pedal rotor42and the return rotor52. Together with the biasing force of the first spring60and the second spring61, the rotational resistance is transmitted to the operational member41. As shown by a solid line inFIG. 3, the rotational resistance acts such that a depression force increases when the accelerator pedal40is depressed to increase the rotational angle. As shown by a dashed-dotted line inFIG. 3, the rotational resistance acts such that the depression force decreases when the accelerator pedal40is returned to decrease the rotational angle. The first inclined tooth47and the second inclined tooth54may function as a resistance application unit to apply a rotational resistance to the operational member41according to the rotation angle of the pedal rotor42.

Subsequently, a configuration of the accelerator device10will be described with reference toFIGS. 1 to 6. As shown inFIG. 2andFIG. 4, the first frictional member65has a slidable portion70, a first latch portion71, and a second latch portion72. The slidable portion70is in an annular shape and is slidable relative to the return rotor52. The first latch portion71and the second latch portion72are distant from each other in the rotational direction. The first latch portion71and the second latch portion72are projected from the slidable portion70outward in the radial direction. The first latch portion71and the second latch portion72are connected to each other at base ends. The first latch portion71and the second latch portion72form a fitting groove (interspace)73therebetween. The fitting groove73is in a notch shape.

The housing20has a rotation restrictive projection74. The rotation restrictive projection74is fitted in the fitting groove73, which is formed between the first latch portion71and the second latch portion72of the first frictional member65. In the present embodiment, the projection74is press-fitted in the fitting groove73. The housing20has a latch projected portion75, which is in an annular shape. The latch projected portion75is fitted to the slidable portion70of the first frictional member65and located inside the slidable portion70in the radial direction. In the present embodiment, the latch projected portion75is press-fitted in the slidable portion70. In the configuration including the first frictional member65, the housing20, and the accelerator pedal40, the housing20may function as a first member, and the accelerator pedal40may function as a second member.

A clearance (first rotational clearance)76is formed on the opposite side of the first latch portion71of the first frictional member65from the rotation restrictive projection74. The clearance76allows expansion of the first latch portion71in the rotational direction. A clearance (second rotational clearance)77is formed on the opposite side of the second latch portion72of the first frictional member65from the rotation restrictive projection74. The clearance77allows expansion of the second latch portion72in the rotational direction. A clearance (first radial clearance)78resides on the outside of the first latch portion71of the first frictional member65in the radial direction. The clearance78allows expansion of the first latch portion71outward in the radial direction. A clearance (second radial clearance)79resides on the outside of the second latch portion72of the first frictional member65in the radial direction. The clearance79allows expansion of the second latch portion72outward in the radial direction. The clearances76,77,78, and79are the same space and belong to a common clearance. The first frictional member65has a connection portion at which the first latch portion71and the second latch portion72are connected to each other, and a clearance80resides on the outside of the connection portion in the radial direction. The clearance80allows expansion of the connection portion and the slidable portion70outward in the radial direction.

As shown inFIG. 2,FIG. 5, andFIG. 6, the second frictional member66has a slidable portion81, a first latch portion82, and a second latch portion83. The slidable portion81is in an annular shape and is slidable relative to the housing20. The first latch portion82and the second latch portion83are distant from each other in the rotational direction. The first latch portion82and the second latch portion83are closer to the pedal rotor42than the slidable portion81in the axial direction. The first latch portion82and the second latch portion83form a fitting groove (interspace)84therebetween. The fitting groove84is in a notch shape. In the present embodiment, the fitting groove84is formed at each of four positions at regular intervals in the rotational direction.

The pedal rotor42has four rotation restrictive projections85to restrict rotation. Each of the rotation restrictive projections85is fitted to the fitting groove84, which is formed between the first latch portion82and the second latch portion83of the second frictional member66. In the present embodiment, the projection85is press-fitted in the fitting groove84. In the configuration including the second frictional member66, the housing20, and the accelerator pedal40, the accelerator pedal40may function as a first member, and the housing20may function as a second member.

A clearance (first rotational clearance)86resides on the opposite side of the first latch portion82of the second frictional member66from the rotation restrictive projection85. The clearance86allows expansion of the first latch portion82in the rotational direction. A clearance (second rotational clearance)87resides on the opposite side of the second latch portion83of the second frictional member66from the rotation restrictive projection85. The clearance87allows expansion of the second latch portion83in the rotational direction. A clearance (first radial clearance)88resides on the outside of the first latch portion82of the second frictional member66in the radial direction. The clearance88allows expansion of the first latch portion82outward in the radial direction. A clearance (second radial clearance)89resides on the outside of the second latch portion83of the second frictional member66in the radial direction. The clearance89allows expansion of the second latch portion83outward in the radial direction. The clearances86,87,88, and89are the same space and belong to a common clearance.

As described above, the accelerator device10according to the first embodiment includes the first frictional member65, which has the first latch portion71and the second latch portion72. The first latch portion71and the second latch portion72are arranged to be distant from each other in the rotational direction. The housing20has the rotation restrictive projection74. The rotation restrictive projection74is fitted in the fitting groove73, which is formed between the first latch portion71and the second latch portion72of the first frictional member65. The second frictional member66includes the first latch portion82and the second latch portion83. The first latch portion82and the second latch portion83are arranged to be distant from each other in the rotational direction. The pedal rotor42has the rotation restrictive projections85. Each of the rotation restrictive projections85is fitted in the corresponding fitting groove84, which is formed between the first latch portion82and the second latch portion83of the second frictional member66.

When the accelerator device10is in an operation environment at high temperature, the first frictional member65and the second frictional member66may expand. Even in such a state, the present configuration enables to expand the fitting groove73of the first frictional member65and the fitting groove84of the second frictional member66in the rotational direction. Thus, the present configuration enables to restrict the first latch portion71and the second latch portion72of the first frictional member65from being urged onto the projection74of the housing20. In addition, the present configuration enables to restrict the first latch portion82and the second latch portion83of the second frictional member66from being urged onto the projection85of the pedal rotor42. Therefore, even when temperature of the operation environment of the accelerator device10increases and decreases repeatedly, the latch portions71,72,82, and83can be protected from deformation. Thus, the present configuration enables to maintain an operational feeling of the accelerator pedal40.

Second Embodiment

An accelerator device according to a second embodiment of the present disclosure will be described with reference toFIG. 7. As shown inFIG. 7, a first frictional member90includes a slidable portion91, a first latch portion92, and a second latch portion93. The slidable portion91is in an annular shape and is slidable relative to a return rotor. The first latch portion92and the second latch portion93arranged to be distant from each other in the rotational direction. The first latch portion92and the second latch portion93are located on the inside of the slidable portion91in the radial direction. The first latch portion92and the second latch portion93form a fitting groove (interspace)94therebetween. The fitting groove94is in a notch shape.

A housing (support member)95has a rotation restrictive projection96. The rotation restrictive projection96is fitted in the fitting groove94, which is formed between the first latch portion92and the second latch portion93of the first frictional member90. In the present embodiment, the projection96is press-fitted in the fitting groove94. The housing95has a latch projected portion97, which is in an annular shape. The latch projected portion97is fitted in the first frictional member90and is located on the inside of the first frictional member90in the radial direction. In the configuration including the first frictional member90, the housing95, and the accelerator pedal, the housing95may function as a first member, and the accelerator pedal may function as a second member.

According to the second embodiment, even when the first frictional member90expands in an operation environment at high temperature, the first latch portion92and the second latch portion93of the first frictional member90can be restricted from being urged onto the projection96of the housing95. Therefore, even when temperature of the operation environment of the accelerator device increases and decreases repeatedly, the latch portions92and93can be protected from deformation. Thus, similarly to the first embodiment, the present configuration enables to maintain an operational feeling of the accelerator pedal.

Other Embodiment

According to another embodiment of the present disclosure, the first frictional member may be mounted to the return rotor. The second frictional member may be mounted to the housing.

According to another embodiment of the present disclosure, the inside of the first latch portion of the first frictional member in the radial direction and the inside of the second latch portion in the radial direction may be connected to each other. In addition, the outside of the first latch portion in the radial direction and the outside of the second latch portion in the radial direction may be connected to each other. In the present configuration, the first latch portion and the second latch portion of the first frictional member may form a hole therebetween, and the hole may extend in the axial direction. In the present configuration, the projection, which forms the first member, may be fitted in the hole.

According to another embodiment of the present disclosure, in the second frictional member, the inside of the first latch portion in the radial direction and the inside of the second latch portion in the radial direction may be connected to each other. In addition, the outside of the first latch portion in the radial direction and the outside of the second latch portion in the radial direction may be connected to each other. In the present configuration of the second frictional member, the first latch portion and the second latch portion may form a hole therebetween, and the hole may extend in the axial direction. In the present configuration, the projection, which forms the first member, may be fitted in the hole.

According to another embodiment of the present disclosure, the resistance application unit may have a configuration other than the inclined teeth.

The accelerator device according to the present disclosure includes the support member attachable to the vehicle body. The accelerator device further includes the accelerator pedal supported by the support member and rotatable from the full close position to the full open position. The accelerator device further includes the biasing member configured to bias the accelerator pedal to the full close position. The accelerator device further includes the frictional member located between the support member and the accelerator pedal. The accelerator device further includes the resistance application unit configured to apply rotational resistance to the accelerator pedal. The frictional member is mounted to a first member and is frictionally slidable on a second member. The first member is one of the support member and the accelerator pedal. The second member is the other of the support member and the accelerator pedal. The resistance application unit is configured, as the rotation angle of the accelerator pedal increases from the full close position, to increase the frictional force between the second member and the frictional member and to increase the rotational resistance applied from the frictional member to the accelerator pedal.

In the above-described example, the frictional member forms the first latch portion and the second latch portion, and the first member forms the projection. The first latch portion and the second latch portion of the frictional member form a interspace in the rotational direction. The projection of the first member is fitted between the first latch portion and second latch portion of the frictional member to restrict rotation.

When the accelerator device is in the operation environment at high temperature, the frictional member may expand. At this time, the first latch portion and the second latch portion of the frictional member also expand, such that the distance between the first latch portion and the second latch portion becomes large. Consequently, the present configuration enables to restrict the first latch portion and the second latch portion from being urged onto the projection of the first member. Therefore, even when temperature of the operation environment of the accelerator device increases and decreases repeatedly, the first latch portion and the second latch portion of the frictional member can be protected from deformation. Thus, the present configuration enables to maintain the operational feeling of the accelerator pedal.