JP6943611B2 - Electric parking brake mechanism - Google Patents

Description

The present invention relates to an electric parking brake mechanism.

As a conventional electric parking brake mechanism, for example, the one described in Patent Document 1 is known. Patent Document 1 discloses an electric parking brake mechanism in which a rotation linear motion conversion mechanism that converts a rotational force of an electric motor into a propulsive force of a piston of a master cylinder is attached to a housing. This rotary linear motion conversion mechanism includes a nut portion (rotary member) that is rotatably supported by a housing and is rotationally driven by an electric motor, and a screw shaft (linear motion member) that moves forward and backward according to the rotation of the nut portion. , Is equipped.

Japanese Unexamined Patent Publication No. 2016-222111

Some electric parking brake mechanisms are provided with a load sensor that detects the load acting on the linear motion member in order to adjust the degree of application of the parking brake. In this load sensor, an elastic member is arranged between a fixed portion fixed to the housing and a movable portion connected to the rotating member of the rotation linear motion conversion mechanism, and is based on the amount of movement of the movable portion with respect to the fixed portion. The load acting on the linear motion member is detected. Then, the upper limit value of the load acting on the linear motion member is set so that the load acting on the linear motion member does not become excessive, and the electric motor is driven and controlled so that the detected value of the load sensor does not exceed the upper limit value. doing.

However, if the electric motor is driven until the detected value of the load sensor exceeds the upper limit value due to an erroneous operation by an operator or the like, the amount of deformation of the elastic member of the load sensor may become excessive and the elastic member may be plastically deformed. .. As a result, there is a problem that the life of the load sensor is shortened.

Therefore, it is an object of the present invention to provide an electric parking brake mechanism capable of suppressing a decrease in the life of a load sensor.

The electric parking brake mechanism according to the present invention includes a housing, a rotating member that is rotationally driven around a rotating axis by an electric motor and held in the housing so as to be movable in the direction of the rotating axis along the rotating axis. Has a linear motion member that moves in the direction of the rotation axis of the rotating member with respect to the rotating member, and when the rotating member rotates in the first rotation direction, the linear motion member is pulled into the rotating member to apply the parking brake. A rotary linear motion conversion mechanism that operates, a movable portion that is connected to a rotating member and can move in the direction of the rotation axis, a fixed portion that is fixed to the housing, and a fixed portion that is arranged between the movable portion and the fixed portion. A load sensor having an elastic member that elastically supports the movable portion in the direction of the rotation axis and a detection unit that detects a load acting on the linear moving member based on the amount of movement of the movable portion with respect to the fixed portion, and a housing. It is provided with a regulating portion that regulates the movement of the rotating member in the rotation axis direction by abutting against the rotating member when the rotating member is fixed and rotates in the first rotation direction.

In this electric parking brake mechanism, when the rotating member is rotated in the first rotation direction by the electric motor, the linear motion member is pulled into the rotating member to operate the parking brake. Here, the rotating member is held in the housing so as to be movable in the direction of the rotation axis, and in the load sensor, an elastic member is formed between the movable portion connected to the rotating member and the fixed portion fixed to the housing. Are arranged. Therefore, the rotating member moves in the second direction, which is the direction opposite to the first direction in which the linear moving member is pulled into the rotating member, while elastically deforming the elastic member by pulling in the linear moving member. Therefore, the detection unit detects the amount of movement of the movable portion with respect to the fixed portion, so that the load acting on the linear motion member can be detected.

Then, when the rotating member is continuously rotated in the first rotation direction by the electric motor, the rotating member also continues to move in the second direction, so that the amount of deformation of the elastic member increases. However, since the restricting portion restricts the movement of the rotating member with respect to the housing in the second direction, it is possible to prevent the elastic member from being deformed excessively. As a result, it is possible to prevent the life of the load sensor from being shortened.

Moreover, even if the restricting portion restricts the movement of the rotating member with respect to the housing in the second direction, the rotating member can rotate in the first rotating direction. It becomes possible to apply a load to.

The regulating portion has a fixing portion fixed to the housing and a contact portion that comes into contact with the rotating member, and the contact portion is a contact portion when the rotating member of the rotating member rotates in the first rotation direction. The linear motion member may be arranged on the second direction side, which is the direction opposite to the first direction in which the linear motion member is drawn into the rotating member. In this electric parking brake mechanism, since the contact portion of the regulating portion is arranged on the second direction side of the rotating member, the amount of movement of the rotating member in the second direction when the rotating member rotates in the first rotation direction. Can be prevented from becoming excessive and the amount of deformation of the elastic member becoming excessive.

The restricting portion may be fixed to the housing so as to be movable in the direction of the rotation axis. When the rotating member is rotated in the first rotation direction by the electric motor, there is a correlation between the amount of movement of the rotating member and the load acting on the linearly moving member until the movement of the rotating member is regulated by the regulating portion. Therefore, in this electric parking brake mechanism, since the regulating portion is fixed to the housing so as to be movable in the direction of the rotation axis, the load acting on the linear moving member when the regulating portion regulates the movement of the rotating member is adjusted. Can be done.

The regulating portion has a through hole into which a bolt for fastening the regulating portion to the housing is inserted, and the through hole may be an elongated hole long in the rotation axis direction. In this electric parking brake mechanism, the through hole into which the bolt for fastening the regulation part to the housing is inserted is a long hole that is long in the direction of the rotation axis. The fixed position can be adjusted.

According to the present invention, it is possible to suppress a decrease in the life of the load sensor.

It is the schematic sectional drawing which shows the electric parking brake mechanism which concerns on one Embodiment. It is an enlarged schematic cross-sectional view of the connecting part of a rotating member and a linear motion member. It is a schematic cross-sectional view taken along the line III-III in FIG. It is a schematic cross-sectional view which enlarged the peripheral part of a load sensor. 5 (a) is a front view of the regulation unit, FIG. 5 (b) is a plan view of the regulation unit, and FIG. 5 (c) is a side view of the regulation unit. FIG. 6A is an enlarged schematic cross-sectional view of the peripheral portion of the regulation portion, and FIG. 6B is a schematic cross-sectional view taken along the line bb in FIG. 6A. It is a figure for demonstrating the fixing method of the regulation part with respect to a housing.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the drawings. In the following description, the same reference numerals will be used for the same or equivalent elements, and duplicate description will be omitted.

The electric parking brake mechanism of the present embodiment is a mechanism mounted on a vehicle (not shown) for electrically operating the parking brake. As shown in FIG. 1, the electric parking brake mechanism 1 includes a housing 2, a rotation linear motion conversion mechanism 3, a load sensor 4, and a regulation unit 5.

The housing 2 is a member that functions as a housing of the electric parking brake mechanism 1 and is fixed to the vehicle.

As shown in FIGS. 1 to 3, the rotation linear motion conversion mechanism 3 is a mechanism that converts a rotational motion into a linear motion. The rotary linear motion conversion mechanism 3 includes an electric motor 11, a rotary member 12, and a linear motion member 13.

The electric motor 11 is a rotation drive source of the rotation linear motion conversion mechanism 3, and rotates the output shaft by electric power.

The rotating member 12 is rotationally driven around the rotation axis A by the electric motor 11. Specifically, the gear 14 is fitted on the outer peripheral surface of the rotating member 12. The rotating member 12 and the gear 14 cannot rotate relative to each other around the rotation axis A. That is, the outer peripheral surface of the rotating member 12 and the inner peripheral surface of the gear 14 have a shape in which the gear 14 does not slip with respect to the rotating member 12, for example, a shape other than a perfect circle. In the present embodiment, as shown in FIG. 3, the outer peripheral surface of the rotating member 12 and the inner peripheral surface of the gear 14 are formed in a chamfered square. The rotating member 12 and the gear 14 may be relatively movable in the direction of the rotation axis, or may not be relatively movable in the direction of the rotation axis. The direction of the rotation axis is the direction in which the rotation axis A extends. The gear 14 is connected to the output shaft of the electric motor 11 via a rotation transmission member 17 such as one or a plurality of gears and a pulley belt. Therefore, when the electric motor 11 rotates the output shaft, this rotational driving force is transmitted to the gear 14 and the rotating member 12 via the rotation transmitting member 17. As a result, the rotating member 12 rotates around the rotation axis A.

The rotating member 12 is held in the housing 2 so as to be movable in the direction of the rotation axis. For example, at least one of the rotating member 12 and the housing 2 is formed with a guide groove extending in the direction of the rotation axis, and the rotating member 12 and the housing 2 can move relative to each other along the guide groove. As a result, the rotating member 12 can move with respect to the housing 2 in the direction of the rotation axis. When the rotating member 12 and the gear 14 can move relative to each other in the direction of the rotation axis, the rotating member 12 can move in the direction of the rotation axis with respect to the housing 2 independently of the gear 14. On the other hand, when the rotating member 12 and the gear 14 are relatively immovable in the rotation axis direction, the rotating member 12 can move integrally with the gear 14 in the rotation axis direction with respect to the housing 2.

A spiral groove 15 is formed on the inner peripheral surface of the rotating member 12. The spiral groove 15 is a groove for moving the linear motion member 13 in the direction of the rotation axis when the rotary member 12 rotates. The groove shape of the spiral groove 15 can be, for example, a trapezoid that can withstand a large load.

The linear motion member 13 is connected to a wire (not shown) that generates the hydraulic pressure of the parking brake, and when the rotary member 12 rotates, the linear motion member 13 moves with respect to the rotary member 12 in the direction of the rotation axis of the rotary member 12. Specifically, a spiral groove 16 corresponding to the spiral groove 15 of the rotating member 12 is formed on the outer peripheral surface of the linear motion member 13. The spiral groove 16 of the linear motion member 13 meshes with the spiral groove 15 of the rotating member 12. Therefore, as the rotating member 12 rotates, the linear motion member 13 moves in the direction of the rotation axis. That is, when the rotating member 12 rotates in the first rotation direction, the linear motion member 13 is pulled into the rotating member 12. This activates the parking brake. On the other hand, when the rotating member 12 rotates in the second rotation direction, which is the direction opposite to the first rotation direction, the linear motion member 13 is pushed out from the rotating member 12.

Here, the direction in which the linear moving member 13 is pulled into the rotating member 12 by rotating the rotating member 12 in the first rotation direction is referred to as the first direction B, which is the direction opposite to the first direction B. The direction in which the linear motion member 13 is pushed out from the rotary member 12 by rotating the rotary member 12 in the second rotation direction is referred to as the second direction C.

As shown in FIGS. 1 and 4, the load sensor 4 detects the load acting on the linear motion member 13 (the wire that generates the oil pressure of the parking brake). The load sensor 4 includes a movable portion 21, a fixing portion 22, an elastic member 23, and a detecting portion 24.

The movable portion 21 is connected to the rotating member 12 and can move in the direction of the rotation axis. The movable portion 21 is formed in a box shape and also functions as a housing for the load sensor 4. The movable portion 21 is connected to the rotating member 12 by a connecting member 25. The connecting member 25 may connect the rotating member 12 and the movable portion 21 so that the rotating member 12 and the movable portion 21 are integrated, but at least when the rotating member 12 moves in the second direction C, the movable portion 21 is connected. The rotating member 12 and the movable portion 21 may be connected so that the 21 also moves in the second direction C.

The fixing portion 22 is fixed to the housing 2. The fixed portion 22 extends from a fixed position fixed to the housing 2 in a rod shape along the rotation axis A and is inserted into the internal space of the movable portion 21. A flange portion 22a extending in a direction orthogonal to the rotation axis A is formed at the tip portion of the fixed portion 22 located in the internal space of the movable portion 21 on the second direction C side.

The elastic member 23 is arranged between the movable portion 21 and the fixed portion 22, and elastically supports the movable portion 21 with respect to the fixed portion 22 in the direction of the rotation axis. Specifically, the elastic member 23 is composed of a coil spring. The elastic member 23 is arranged between the flange portion 22a of the fixed portion 22 and the wall portion 21a facing the flange portion 22a of the movable portion 21. Therefore, the elastic member 23 urges the movable portion 21 with respect to the fixed portion 22 in the second direction C, and by resisting the elastic force of the elastic member 23, the elastic member 23 is movable with respect to the fixed portion 22. The portion 21 can be moved in the second direction C.

The detection unit 24 detects the load acting on the linear motion member 13 based on the amount of movement of the movable unit 21 with respect to the fixed unit 22. Specifically, the detection unit 24 includes a magnet 26 and a sensor unit 27. The magnet 26 is fixed to the movable portion 21 and moves in the direction of the rotation axis together with the movable portion 21. The sensor unit 27 is fixed to the fixing unit 22 so as to be arranged so as to face the magnet 26. Then, the sensor unit 27 detects the amount of movement of the magnet 26, that is, the amount of movement of the movable portion 21 with respect to the fixed portion 22, by detecting the magnetism of the magnet 26. Since there is a correlation between the amount of movement of the movable portion 21 with respect to the fixed portion 22 (the amount of movement of the magnet 26) and the load acting on the linear motion member 13, the sensor portion 27 moves the movable portion 21 with respect to the fixed portion 22. Based on the amount, the load acting on the linear motion member 13 is obtained. The sensor unit 27 has a database showing the correspondence between the amount of movement of the movable portion 21 (the amount of movement of the magnet 26) with respect to the fixed portion 22 and the load acting on the linear motion member 13, and from this database, it is possible to obtain a database. The load acting on the linear motion member 13 may be obtained.

As shown in FIGS. 1, 5 and 6, the regulating portion 5 is fixed to the housing 2, and when the rotating member 12 rotates in the first rotation direction, the regulating portion 5 comes into contact with the rotating member 12 to cause the rotating member 12 to come into contact with the rotating member 12. Regulate the movement in the direction of the rotation axis of. The regulating portion 5 includes a fixing portion 51 and a contact portion 52.

The fixing portion 51 is a portion fixed to the housing 2. The fixing portion 51 is formed in a shape along the inner wall surface of the housing 2. When the fixing surface of the housing 2 to which the fixing portion 51 is fixed is flat, the fixing portion is formed in a flat plate shape. When the fixing surface of the housing 2 to which the fixing portion 51 is fixed has a curved surface shape, the fixing portion 51 is formed in a curved plate shape along the inner wall surface of the housing 2. A plurality of through holes 53 are formed in the fixing portion 51. The through hole 53 is a hole into which a bolt 55 (see FIG. 7) for fastening the regulation portion 5 to the housing 2 is inserted. The through hole 53 is an elongated hole long in the rotation axis direction in order to fix the regulation portion 5 to the housing 2 so as to be movable in the rotation axis direction. Therefore, by adjusting the fastening position of the bolt 55 inserted into the through hole 53, the position of the regulating portion 5 in the rotation axis direction can be adjusted.

The contact portion 52 is a portion that the rotating member 12 comes into contact with when the rotating member 12 rotates in the first rotation direction. The contact portion 52 is formed in a flat plate shape and is bent with respect to the fixed portion 51 so as to be orthogonal to the rotation axis A. Then, the contact portion 52 is arranged on the second direction C side of the rotating member 12. The contact portion 52 is separated from the rotating member 12 before the rotating member 12 rotates in the first rotation direction, and the rotating member 12 rotates in the first rotation direction and moves a predetermined distance in the rotation axis direction. Then, it comes into contact with the rotating member 12.

A penetrating portion 54 is formed in the abutting portion 52. The penetrating portion 54 has a shape that allows the linear motion member 13 to pass through but not the rotating member 12. Specifically, the penetrating portion 54 is formed in a U shape when viewed from the direction of the rotation axis. On the plane orthogonal to the rotating axis A, the inner diameter of the penetrating portion 54 is larger than the maximum outer diameter of the linear motion member 13 and smaller than the maximum outer diameter of the rotating member 12. The maximum outer diameter of the linear motion member 13 means the outer diameter of a circle that passes through the position farthest from the rotation axis A of the linear motion member 13 with the rotation axis A as the center. Similarly, the maximum outer diameter of the rotating member 12 means the outer diameter of a circle that passes through the position farthest from the rotating axis A of the rotating member 12 with the rotating axis A as the center.

Therefore, when the rotating member 12 rotates in the first rotation direction and moves in the second direction C while pulling in the linear motion member 13, the end surface of the rotating member 12 on the first direction B side comes into contact with the contact portion 52. Therefore, the movement of the rotating member 12 in the direction of the rotation axis is restricted. Even if the rotating member 12 comes into contact with the contact portion 52, the rotating member 12 can rotate against the friction with the contact portion 52.

Next, a method of fixing the regulating portion 5 to the housing 2 will be described with reference to FIG. 7.

As shown in FIGS. 1 and 7, the through hole 53 for fixing the fixing portion 51 to the housing 2 is a long hole long in the rotation axis direction, so that the regulation portion 5 is in the second direction of the rotating member 12. The position that restricts the movement to C can be adjusted. Further, by adjusting the position where the regulating unit 5 restricts the movement of the rotating member 12 in the second direction C, the regulating unit 5 directly moves when the rotating member 12 regulates the movement of the rotating member 12 in the second direction C. The load acting on the member 13 can be adjusted.

Therefore, first, the rotating member 12 is rotationally driven by the electric motor 11 in a state where the regulating portion 5 is not fixed to the housing 2. At this time, the regulating portion 5 may be in a state of being removed from the housing 2, and the bolt 55 inserted into the through hole 53 of the regulating portion 5 is screwed into the housing 2, but the restricting portion with respect to the housing 2. 5 may be in a state where it can be moved in the direction of the rotation axis. When the load acting on the linear motion member 13 reaches the set value, the rotary drive of the rotary member 12 by the electric motor 11 is stopped. Then, in this state, the contact portion 52 is brought into contact with the end surface of the rotating member 12 on the first direction B side, and the fixing portion 51 is fixed to the housing 2. As a result, until the load of the set value is applied to the linear motion member 13, the rotating member 12 is allowed to move in the second direction C, and after the load of the set value is applied to the linear motion member 13, the regulation is performed. The portion 5 can restrict the movement of the rotating member 12 in the second direction C.

As described above, in the electric parking brake mechanism 1 according to the present embodiment, when the rotating member 12 is rotated in the first rotation direction by the electric motor 11, the linear motion member 13 is pulled into the rotating member 12 to operate the parking brake. do. Here, the rotating member 12 is held in the housing so as to be movable in the direction of the rotation axis, and in the load sensor 4, the movable portion 21 connected to the rotating member 12 and the fixed portion 22 fixed to the housing 2 are fixed. An elastic member 23 is arranged between the two. Therefore, the rotating member 12 elastically deforms the elastic member 23 by pulling in the linear motion member 13, and the second direction is opposite to the first direction B in which the linear motion member 13 is drawn into the rotating member. Move to C. Therefore, the detection unit 24 can detect the load acting on the linear motion member 13 by detecting the amount of movement of the movable unit 21 with respect to the fixed unit 22.

Then, when the rotating member 12 is continuously rotated in the first rotation direction by the electric motor 11, the rotating member 12 also continues to move in the second direction C, so that the amount of deformation of the elastic member 23 increases. However, since the restricting portion 5 restricts the movement of the rotating member 12 with respect to the housing 2 in the second direction C, it is possible to prevent the elastic member 23 from becoming excessively deformed. As a result, it is possible to prevent the life of the load sensor 4 from being shortened.

Moreover, even if the restricting portion 5 restricts the movement of the rotating member 12 with respect to the housing 2 in the second direction C, the rotating member 12 can rotate in the first rotating direction, so that the linear moving member 13 is further rotated. It is possible to pull it into the 12 and apply a load to the linear motion member 13.

Further, since the contact portion 52 of the regulating portion 5 is arranged on the second direction C side of the rotating member 12, when the rotating member 12 rotates in the first rotation direction, the contact portion 52 moves to the second direction C of the rotating member 12. It is possible to prevent the amount of movement of the elastic member 23 from becoming excessive and the amount of deformation of the elastic member 23 from becoming excessive.

Further, since the regulating portion 5 is fixed to the housing 2 so as to be movable in the direction of the rotation axis, it is possible to adjust the load acting on the linear motion member 13 when the regulating portion 5 regulates the movement of the rotating member 12. ..

Further, since the through hole 53 into which the bolt 55 for fastening the regulating portion 5 to the housing 2 is inserted is long in the rotation axis direction, the fixing position of the regulating portion 5 with respect to the housing 2 can be adjusted by adjusting the fastening position of the bolt 55. Can be adjusted.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.

1 ... Electric parking brake mechanism, 2 ... Housing, 3 ... Rotational linear motion conversion mechanism, 4 ... Load sensor, 5 ... Regulatory part, 11 ... Electric motor, 12 ... Rotating member, 13 ... Linear motion member, 14 ... Gear, 15 ... Spiral groove, 16 ... Spiral groove, 17 ... Rotation transmission member, 21 ... Movable part, 21a ... Wall part, 22 ... Fixed part, 22a ... Flange part, 23 ... Elastic member, 24 ... Detection part, 25 ... Connecting member, 26 ... magnet, 27 ... sensor part, 51 ... fixed part, 52 ... contact part, 53 ... through hole, 54 ... through part, 55 ... bolt, A ... rotating axis, B ... first direction, C ... second direction ..

Claims (3)

With the housing
A rotating member that is rotationally driven around a rotating axis by an electric motor and held in the housing so as to be movable in the direction of the rotating axis along the rotating axis, and the rotating member that rotates with respect to the rotating member. It has a linear motion member that moves in the direction of the rotation axis of the rotary member, and when the rotary member rotates in the first rotation direction, the linear motion member is pulled into the rotary member to operate the parking brake. Conversion mechanism and
A movable portion that is connected to the rotating member and can move in the direction of the rotation axis, a fixed portion that is fixed to the housing, and a fixed portion that is disposed between the movable portion and the fixed portion with respect to the fixed portion. A load sensor having an elastic member that elastically supports the movable portion in the direction of the rotation axis, and a detection unit that detects a load acting on the linearly moving member based on the amount of movement of the movable portion with respect to the fixed portion.
It is composed of a separate part from the housing, and when it is fixed to the housing and the rotating member rotates in the first rotation direction, it comes into contact with the rotating member in the direction of the rotation axis of the rotating member. and a regulating portion for regulating the movement of,
The regulating portion is configured so that its position in the direction of the rotation axis can be adjusted .
Electric parking brake mechanism. The regulating unit has a solid and tough in which a plurality of through holes are formed a bolt for fastening the restricting portion in the housing is inserted, a contact portion which is brought into contact with the rotating member, the ,
The contact portion is arranged on the second direction side of the rotating member, which is the direction opposite to the first direction in which the linear motion member is drawn into the rotating member when the rotating member rotates in the first rotation direction. Be done,
The electric parking brake mechanism according to claim 1. The restricting portion is at a position where the deformation amount of the elastic member is set so as not to exceed a predetermined value, restricts movement of the rotation axis direction of the rotary member in contact with the rotary member, according to claim 1 or 2 Symbol placement of the electric parking brake mechanism.

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