Electric braking device

Abstract

In this electric braking device, a support member (BRC) has a guide surface (Fgd) extending in the sliding direction of a lock pin (LKP), and when the lock pin (LKP) is supported by the support member (BRC), at least part of an outer peripheral side surface of the lock pin (LKP) comes into contact with the guide surface (Fgd), thereby restricting the rotation of the lock pin (LKP) with respect to the support member (BRC).

Description

Electric braking device

[0001] The present disclosure relates to an electric braking device.

[0002] Patent Document 1 discloses a parking brake module that engages a spring-biased pawl with a ratchet gear. In the parking brake module disclosed in Patent Document 1, the spring and the pawl are assembled to an actuation plunger.

[0003] International Publication No. 2024 / 027886

[0004] In a parking brake mechanism that locks a ratchet gear by engaging a claw portion of a lock pin with teeth of the ratchet gear, if the lock pin rotates, the claw portion may not properly engage with the teeth of the ratchet gear. An object of one aspect of the present disclosure is to suitably engage the claw portion of the lock pin with the teeth of the ratchet gear.

[0005] In order to solve the above problem, an electric braking device according to one aspect of the present disclosure generates frictional braking force by pressing a friction member against a rotating member that rotates integrally with a wheel of a vehicle, and locks a ratchet gear configured to be rotatable in conjunction with movement of the friction member by a lock pin supported by a support member and sliding inside the support member, wherein the support member has a guide surface extending in a sliding direction of the lock pin, and the lock pin has a rotation restricting portion that restricts rotation of the lock pin relative to the support member by bringing at least a part of an outer peripheral side surface into contact with the guide surface when the lock pin is supported by the support member.

[0006] According to one aspect of the present disclosure, the claw portion of the lock pin and the teeth of the ratchet gear can be suitably engaged with each other.

[0007] It is a diagram showing the configuration of the electric braking device according to Embodiment 1 of the present disclosure. It is a diagram used for explaining the parking brake mechanism according to Embodiment 1 of the present disclosure. It is a diagram used for explaining the rotation restricting portion according to Embodiment 1 of the present disclosure. It is a plan view showing an example of a lock pin according to Embodiment 2 of the present disclosure. It is a plan view showing an example of a lock pin according to Embodiment 3 of the present disclosure.

[0008] [Embodiment 1] Figure 1 is a diagram showing the configuration of an electric braking device according to Embodiment 1 of the present disclosure. The electric braking device BRK shown in Figure 1 is mounted on a vehicle. The vehicle equipped with the electric braking device BRK includes a braking operating member BP such as a brake pedal, a wheel WHL, and a rotating member KTB that rotates integrally with the wheel WHL. The electric braking device BRK includes a caliper CRP and an electronic control unit ECU.

[0009] The caliper CRP shown in Figure 1 is a floating-type electric caliper. The caliper CRP includes an electric motor MTR, a parking brake mechanism LOK, a reduction member GSK, a shaft SFT, a power conversion member NJB, a pressing member PSN, a pressing force acquisition unit FBA, and two friction members MSB.

[0010] The electric motor MTR is the power source for driving the pressing member PSN. The rotation of the electric motor MTR causes the power transmission member INP to rotate around the rotation axis Jin. The reduction member GSK has multiple reduction gears GR. The multiple reduction gears GR include a first gear GR1 fixed to the power transmission member INP and a second gear GR2 fixed to the shaft SFT. The reduction member GSK transmits the rotation of the power transmission member INP to the shaft SFT at a reduced rotational speed. The shaft SFT is rotatable around the rotation axis Jps.

[0011] The power conversion member NJB is, for example, a ball screw mechanism. The power conversion member NJB converts the rotational power of the shaft SFT into linear power and transmits it to the pressing member PSN. The pressing member PSN is, for example, a piston. The pressing member PSN moves in a direction parallel to the rotation axis Jps by the linear power transmitted from the power conversion member NJB and presses the friction member MSB. The friction member MSB is positioned opposite the rotating member KTB, which rotates integrally with the vehicle's wheel WHL. The pressing force acquisition unit FBA acquires the pressing force, which is the force with which the pressing member PSN presses the friction member MSB.

[0012] The parking brake mechanism LOK is used as a parking brake for a vehicle and includes a ratchet gear RCH and a solenoid SOL. The ratchet gear RCH is configured to rotate around the rotation axis Jin in conjunction with the movement of the friction member MSB.

[0013] The rotation of the electric motor MTR is transmitted to the pressing member PSN by the reduction member GSK. When the electric motor MTR rotates in the forward direction, the pressing member PSN moves linearly in the forward direction, pressing the friction member MSB against the rotating member KTB. This pressing of the friction member MSB against the rotating member KTB generates a frictional braking force. On the other hand, when the electric motor MTR rotates in the reverse direction, opposite to the forward direction, it moves linearly in the backward direction, and the friction member MSB moves away from the rotating member KTB.

[0014] Figure 2 is a diagram used to explain the parking brake mechanism according to Embodiment 1 of the present disclosure. As shown in Figure 2, the parking brake mechanism LOK includes a solenoid SOL, a bracket BRC, a lock pin LKP, an elastic member SPR, and a ratchet gear RCH.

[0015] The solenoid SOL is a pull solenoid comprising a coil COL, a base (fixed iron core) BAS, a plunger (movable iron core) PLN, a push bar PBR, a housing HSG, and an air gap spacer AGS. The coil COL and the base BAS are housed inside the housing HSG. The housing HSG is fixed to the caliper CRP. One end of the push bar PBR contacts the lock pin LKP, and the other end is fixed to the plunger PLN.

[0016] The lock pin LKP has a first part P1 and a second part P2. The first part P1 has a claw portion TSU at its tip. The claw portion TSU faces the tooth surface of the ratchet gear RCH. The second part P2 is integrally formed with the first part P1, with one surface S2 facing the solenoid SOL and provided to be in contact with the push bar PBR.

[0017] Bracket BRC is an example of a support member and supports the lock pin LKP. Bracket BRC has a through hole INS through which the first part P1 of the lock pin LKP is inserted. The through hole INS extends in the axial direction Jpb of the push bar PBR. One opening of the through hole INS faces the tooth surface of the ratchet gear RCH, and the other opening faces the solenoid SOL. Bracket BRC has a guide portion GUD between the other opening of the through hole INS and the solenoid SOL. The guide portion GUD extends in the axial direction Jpb of the push bar PBR and houses a part of the first part P1 and a second part P2 of the lock pin LKP. The second part P2 of the lock pin LKP contacts the push bar PBR inside the guide portion GUD. The guide portion GUD has a guide surface Fgd that extends in the axial direction Jpb of the push bar PBR.

[0018] The outer circumferential surface of the first part P1 of the lock pin LKP has a cylindrical outer circumferential surface shape, and the inner circumferential surface of the insertion hole INS through which the first part P1 is inserted has a cylindrical inner circumferential surface shape. The inner diameter of the inner circumferential surface of the insertion hole INS is set to be slightly larger than the outer diameter of the outer circumferential surface of the first part P1 so that the first part P1 of the lock pin LKP can reciprocate and slide in the axial direction Jpb. At least a portion of the outer circumferential surface of the second part P2 of the lock pin LKP abuts against the guide surface Fgd. The portion of the outer circumferential surface of the second part P2 of the lock pin LKP that abuts against the guide surface Fgd constitutes a rotation restricting portion that restricts the rotation of the lock pin LKP relative to the bracket BRC.

[0019] The guide portion GUD has an elastic member SPR inside. The elastic member SPR is, for example, a coil spring. One end of the elastic member SPR is fixed near the opening of the insertion hole INS, and the other end is fixed to the second part P2 of the lock pin LKP. The elastic member SPR biases the lock pin LKP in the separation direction Dtr, which separates it from the ratchet gear RCH.

[0020] A magnetic field is generated when current flows through the windings of the coil COL. When a magnetic field is generated in the coil COL, the base BAS attracts the plunger PLN in the approaching direction Dts, which is opposite to the separating direction Dtr. The force with which the base BAS attracts the plunger PLN is stronger than the biasing force of the elastic member SPR. As the plunger PLN is attracted to the base BAS against the biasing force of the elastic member SPR, the lock pin LKP is pressed by the plunger PLN and slides in the approaching direction Dts, causing the claw portion TSU of the first part P1 to protrude from the insertion hole INS.

[0021] The ratchet gear RCH has directional teeth. When the ratchet gear RCH rotates in the reverse direction Rvs with the pawl TSU protruding from the insertion hole INS, the pawl TSU engages with the teeth of the ratchet gear RCH. When the pawl TSU is engaged with the pawl TSU of the lock pin LKP, the ratchet gear RCH can rotate in the forward direction Fwd, but cannot rotate in the reverse direction Rvs.

[0022] If the lock pin LKP rotates relative to the bracket BRC, the engagement width of the pawl portion TSU of the lock pin LKP with respect to the teeth of the ratchet gear RCH decreases, impairing the rotation-restricting effect of the ratchet gear RCH. In the lock pin LKP of this disclosure, the second portion P2 constitutes a rotation-restricting portion RR that restricts the rotation of the lock pin LKP relative to the bracket BRC, so that the pawl portion TSU of the lock pin LKP properly engages with the teeth of the ratchet gear RCH.

[0023] (Rotation Restricting Section) Figure 3 is a diagram used to explain the rotation restricting section according to Embodiment 1 of the present disclosure. Figure 3(A) is an example of a side view of the lock pin LKP and bracket BRC according to Embodiment 1 of the present disclosure. Figure 3(B) is an example of a plan view of the lock pin LKP and bracket BRC as seen from the second section P2 side.

[0024] As shown in Figure 3(A), the first part P1 of the lock pin LKP extends in the sliding direction of the lock pin LKP (approaching direction Dts and separating direction Dtr). The second part P2 of the lock pin LKP is integrally arranged alongside the first part P1 in the sliding direction of the lock pin LKP. The central axis J2 of the second part P2 of the lock pin LKP is offset from the central axis J1 of the first part P1.

[0025] As shown in Figure 3(B), the second part P2 of the lock pin LKP has a rotationally symmetric shape with respect to the central axis J2 of the second part P2, and a rotationally symmetric shape with respect to the central axis J1 of the first part P1. The rotationally symmetric shape of the first part P1 with respect to the central axis J1 means that it is not symmetric with respect to a line intersecting the central axis J1 of the first part P1, and does not overlap with itself when rotated (360 / n)° around the central axis J1 of the first part P1 (where n≧2). As shown in Figure 3(B), when the second part P2 is viewed from the direction of the central axis J1 of the first part P1, the point on the outer circumferential surface of the second part P2 that is closest to the central axis J1 of the first part P1 is defined as the first point RP1, and the distance between the first part P1 and the central axis J1 is defined as the first distance L1. If the second point RP2 is defined as the point where a virtual straight line VL extending from the first point RP1 through the central axis J1 of the first part P1 intersects with the outer circumferential surface of the second part P2, then the first distance L1 is different from the second distance L2 between the first part P1 and the central axis J1, and is smaller than the second distance L2. Of the side surfaces of the second part P2 of the lock pin LKP, the surface Frr including the first point RP1 contacts the guide surface Fgd of the bracket BRC, thereby forming a rotation restricting portion that restricts the rotation of the lock pin LKP relative to the bracket BRC.

[0026] [Embodiment 2] Embodiment 2 of the present disclosure will be described below. For the sake of convenience of explanation, components having the same function as those described in Embodiment 1 will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0027] Figure 4 is a plan view showing an example of a lock pin according to Embodiment 2 of the present disclosure. As shown in Figure 4, the lock pin LKP according to Embodiment 2 of the present disclosure has a rectangular cross-section perpendicular to the central axis J1 of the first part P1, and is not symmetrical with respect to a line segment passing through the central axis J2 of the second part P2. In the lock pin LKP according to Embodiment 2 of the present disclosure, not only does the surface Frr of the second part P2 abut against the guide surface Fgd of the bracket BRC, but the first part P1 also abuts against the insertion hole INS, thereby forming a rotation restricting portion that restricts the rotation of the lock pin LKP relative to the bracket BRC.

[0028] [Embodiment 3] Embodiment 3 of the present disclosure will be described below. For the sake of convenience of explanation, components having the same function as those described in Embodiments 1 and 2 above will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0029] Figure 5 is a plan view showing an example of a lock pin according to Embodiment 3 of the present disclosure. As shown in Figure 5, the lock pin LKP according to Embodiment 3 of the present disclosure has a recess OUB on a part of the outer peripheral surface of the second part P2, and when viewed in the sliding direction of the lock pin LKP, the outer shape is asymmetrical. The bracket BRC has a protrusion TTB at a position opposite the recess OUB that fits into the recess OUB. Therefore, when assembling the lock pin LKP to the bracket BRC, the orientation of the lock pin LKP relative to the bracket BRC is a single angle out of 360 degrees.

[0030] In the third embodiment of the present disclosure, the lock pin LKP not only has the surface Frr of the second part P2 in contact with the guide surface Fgd of the bracket BRC, but the recess OUB also fits with the convex part TTB of the bracket BRC, thereby forming a rotation restricting portion that restricts the rotation of the lock pin LKP relative to the bracket BRC.

[0031] [Modification] In the above embodiment 3, the lock pin LKP has a recess OUB on a part of the outer peripheral surface of the second part P2, and the bracket BRC has a protrusion TTB that fits into the recess OUB at a position opposite to the recess OUB. However, the lock pin LKP may have the recess OUB in the first part P1. The bracket BRC may have a protrusion TTB on the inner peripheral side wall of the insertion hole INS at a position opposite to the recess OUB of the first part P1.

[0032] In the above embodiment 3, the lock pin LKP has a recess OUB on a part of the outer peripheral surface of the second part P2, and the bracket BRC has a protrusion TTB at a position opposite to the recess OUB that fits into the recess OUB. However, as long as the recess OUB and the protrusion TTB are formed to fit into each other, the protrusion TTB may be provided on a part of the outer peripheral surface of the second part P2 and the recess OUB may be provided on the bracket BRC.

[0033] [Summary] An electric braking device according to Embodiment 1 of the present disclosure generates a frictional braking force by pressing a friction member against a rotating member that rotates integrally with the wheel of a vehicle, and locks a ratchet gear, which is configured to rotate in conjunction with the movement of the friction member, with a lock pin that is supported by a support member and slides within the support member, wherein the support member has a guide surface extending in the sliding direction of the lock pin, and the lock pin has a rotation restricting portion that restricts the rotation of the lock pin relative to the support member by having at least a part of its outer peripheral surface contact the guide surface when it is supported by the support member. According to the present disclosure, the rotation restriction of the lock pin by the rotation restricting portion makes it possible to make a good angle between the claw portion of the lock pin and the teeth of the ratchet gear, and allows the claw portion of the lock pin and the teeth of the ratchet gear to mesh nicely.

[0034] The electric braking device according to Embodiment 2 of the present disclosure, in Embodiment 1, has a lock pin having a first portion extending in the sliding direction of the lock pin and a second portion having a rotation restricting portion and being integrally arranged alongside the first portion in the sliding direction of the lock pin, wherein the rotation restricting portion has a non-rotationally symmetric shape with respect to the central axis of the first portion, and the support member has an insertion portion through which the first portion is inserted, and with the first portion inserted in the insertion portion, the guide surface abuts with at least the position on the outer peripheral surface of the second portion closest to the central axis of the first portion. According to the present disclosure, the second portion has a non-rotationally symmetric shape with respect to the central axis of the first portion, and the guide surface abuts with the part of the outer shape of the second portion closest to the central axis of the first portion. As a result, when the lock pin is assembled to the support member in such a way that the second portion of the lock pin does not interfere with the support member, the orientation of the lock pin with respect to the support member is determined, and it is possible to prevent the lock pin from being assembled to the support member in the wrong direction.

[0035] In the electric braking device according to embodiment 3 of the present disclosure, in embodiment 2, the external shape of the rotation restricting portion is rotationally symmetric with respect to the central axis of the second portion, and the second portion is integrally formed with the first portion with respect to the central axis of the second portion offset from the central axis of the first portion. According to the present disclosure, the second portion of the lock pin is rotationally symmetric with respect to the central axis of the second portion, and has a shape suitable for mass production. Therefore, the pawl portion of the lock pin and the teeth of the ratchet gear can be suitably engaged without increasing the production cost of the electric braking device.

[0036] In the electric braking device according to aspect 4 of the present disclosure, in aspect 2 or 3, when the second part is viewed from the direction of the central axis of the first part, the first distance between the first point on the outer peripheral surface of the second part that is closest to the central axis of the first part and the central axis of the first part is smaller than the second distance between the central axis of the first part and the second point where a virtual straight line extending from the first point through the central axis of the first part intersects the outer peripheral surface of the second part with the central axis of the first part. According to the present disclosure, in addition to the reversed assembly of the lock pin described above, assembly at other angles (e.g., 90 degrees) can also be prevented.

[0037] In the electric braking device according to aspect 5 of the present disclosure, in aspects 1 to 4, the lock pin has an outer shape that is rotationally symmetric when viewed in the sliding direction of the lock pin, with at least a portion of the outer peripheral surface extending in the sliding direction of the lock pin, and the portion having the rotationally symmetric shape forms the rotation restricting portion. According to the present disclosure, when assembling the lock pin to the support member, the orientation of the first portion around the central axis can be set to a single angle out of 360 degrees. For example, it becomes possible to prevent assembly in the wrong direction.

[0038] [Additional Notes] This disclosure is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this disclosure.

Claims

An electric braking device that generates frictional braking force by pressing a friction member against a rotating member that rotates integrally with the vehicle's wheels, and locks a ratchet gear, which is configured to rotate in conjunction with the movement of the friction member, with a lock pin that is supported by a support member and slides within the support member, The support member has a guide surface that extends in the sliding direction of the lock pin, An electric braking device wherein the lock pin has a rotation restricting portion that restricts the rotation of the lock pin relative to the support member by having at least a portion of its outer peripheral surface contact the guide surface when the lock pin is supported by the support member. 　 The aforementioned locking pin is The first part of the lock pin extends in the sliding direction, It has the rotation restricting portion and a second portion which is integrally arranged alongside the first portion in the sliding direction of the lock pin, The rotation restricting portion has a non-rotationally symmetrical shape with respect to the central axis of the first portion. The aforementioned support member is The first part has an insertion portion through which it is inserted, With the first part inserted into the insertion portion, the guide surface abuts against at least the outer peripheral surface of the second part closest to the central axis of the first part, according to claim 1. 　 The external shape of the rotation restricting part is rotationally symmetrical with respect to the central axis of the second part. The electric braking device according to claim 2, wherein the second part is integrally formed with the first part, with the central axis of the second part being offset from the central axis of the first part. 　 The electric braking device according to claim 2 or 3, wherein, when the second part is viewed from the direction of the central axis of the first part, the first distance between at least one first point on the outer peripheral surface of the second part that is closest to the central axis of the first part and the central axis of the first part is smaller than the second distance between the central axis of the first part and a second point where a virtual straight line extending from the first point through the central axis of the first part intersects the outer peripheral surface of the second part with the central axis of the first part. 　 The electric braking device according to claim 1, wherein at least a portion of the outer peripheral surface extending in the sliding direction of the lock pin has an asymmetrical shape when viewed in the sliding direction of the lock pin, and the portion having the asymmetrical shape forms the rotation restricting portion.

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