Non-excitation type brakes and disc brake systems for braking systems

Abstract

To achieve a nonexcitation-operated brake which suppresses the occurence of magnetic flux leakage and can sufficiently secure a magnetic attraction force moving an armature in a direction toward an electromagnetic coil.SOLUTION: A disc brake device is constituted by including: a coil housing part 91 which allows a casing 81 constituting a nonexcitation-operated brake 42 to function as a yoke and is annularly formed to have a U-shaped cross section as a whole; and an auxiliary yoke 90 which has an approximately cylindrical shape, is engaged within the coil housing part 91 and is provided separately from the coil housing part 91.SELECTED DRAWING: Figure 19

Description

[Technical Field]

[0001] The present invention relates to a non-excitation-operated brake and a disc brake device for brake systems. [Background technology]

[0002] Disc brakes are increasingly being used not only on the front wheels but also on the rear wheels of automobiles due to their excellent heat dissipation and the ability to finely adjust braking force during driving.

[0003] Disc brake systems can be broadly classified into two types: hydraulic disc brake systems, which use hydraulic fluid to obtain braking force, and electrically driven disc brake systems, which use electrically driven actuators to obtain braking force.

[0004] As an electrically operated disc brake device, an electric parking brake type structure is known, as disclosed in Japanese Patent Publication No. 2018-184093, in which braking force from the service brake is generated by supplying brake oil (fluid) into a cylinder, and braking force from the parking brake is generated by driving an electric actuator such as a rotary-to-linear motion conversion mechanism with an electric motor.

[0005] In an electric parking brake type disc brake system, it is necessary to maintain braking force through the parking brake even when the vehicle's engine is stopped and power to the electric motor is cut off.

[0006] Therefore, as disclosed in Japanese Patent Publication No. 2016-50629 and others, it is conceivable to provide a worm gear reduction mechanism with a self-locking function between the electric motor and the piston that presses the pad. With such a configuration, even when the automobile engine is stopped and power to the electric motor is cut off, it is possible to maintain the state in which the pad remains pressed against the rotor, and thus maintain the braking force of the parking brake. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2018-184093 [Patent Document 2] Japanese Patent Publication No. 2016-50629 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] A worm gear reduction mechanism with a self-locking function tends to have greater frictional resistance (energy loss) and lower input / output characteristics (efficiency) compared to a worm gear reduction mechanism without a self-locking function.

[0009] In light of these circumstances, the inventors considered using a non-excitation-operated brake instead of a worm gear reduction mechanism with a self-locking function, thereby maintaining braking force from the parking brake while the automobile engine is stopped and power to the electric motor is cut off.

[0010] An undisclosed non-excitation type brake conceived by the present inventors prior to completing the present invention comprises an electromagnetic coil, a yoke which is a press-formed product housing the electromagnetic coil, an armature, a fixed plate fixed to the yoke, a rotating disc disposed between the fixed plate and the armature and engaged with the motor shaft of an electric motor in such a way that it can be displaced axially with respect to the motor shaft but cannot be displaced relative to it in the circumferential direction, and a compression spring which biases the armature toward the fixed plate.

[0011] When the electromagnetic coil is energized, the no-excitation operation type brake forms a magnetic circuit in the yoke and the armature. As a result, the armature is moved (magnetically attracted) in a direction approaching the electromagnetic coil against the elastic force of the pressing spring. As a result, the rotating disk does not need to be pressed against the fixed plate by the armature, and thus rotation of the motor shaft is permitted. Thus, when the engine of an automobile is operating and the electromagnetic coil is energized, the no-excitation operation type brake permits rotation of the motor shaft.

[0012] On the other hand, when the energization of the electromagnetic coil is stopped (non-energized state), a magnetic circuit like that during energization is not formed in the yoke and the armature. For this reason, the rotating disk is pressed against the fixed plate by the armature and frictionally engages with the fixed plate. As a result, rotation of the motor shaft is blocked. Thus, the no-excitation operation type brake can hold the braking force by the parking brake in a state where the engine of the automobile is stopped and the energization of the electromagnetic coil is stopped.

[0013] However, the no-excitation operation type brake according to the prior invention has room for improvement in that magnetic flux leakage is likely to occur when the electromagnetic coil is energized, and the force (magnetic attraction force) for moving the armature in a direction approaching the electromagnetic coil is likely to be insufficient.

[0014] The present invention has been made to solve the above problems, and an object thereof is to provide a no-excitation operation type brake for a brake device that can suppress the occurrence of magnetic flux leakage and sufficiently secure a magnetic attraction force for moving an armature in a direction approaching an electromagnetic coil.

Means for Solving the Problems

[0015] The inventors of the present invention have conducted intensive research on the reasons for the occurrence of magnetic flux leakage, and as a result, have obtained the knowledge that the cause lies in the thickness dimension of the yoke. That is, it is desirable that the yoke be manufactured by press working for reasons such as cost reduction. However, when the yoke is manufactured by press working, usually, the thickness dimension of the yoke becomes substantially constant. Further, the yoke has a substantially U-shaped cross-sectional shape so as to cover the periphery of the electromagnetic coil, and is configured in an annular shape as a whole. Therefore, when the yoke is manufactured by press working, the thickness dimension of the inner peripheral side wall portion disposed on the inner side in the radial direction of the electromagnetic coil and the thickness dimension of the outer peripheral side wall portion disposed on the outer side in the radial direction of the electromagnetic coil of the yoke become the same. However, based on the fact that the diameter of the inner peripheral side wall portion is smaller than the diameter of the outer peripheral side wall portion, the cross-sectional area of the inner peripheral side wall portion is smaller than the cross-sectional area of the outer peripheral side wall portion with respect to a virtual plane orthogonal to the central axis. Therefore, the magnetic flux passing through the inside of the inner peripheral side wall portion becomes less than the magnetic flux passing through the inside of the outer peripheral side wall portion. As a result, it has been found that when the thickness dimension of the yoke is constant, the magnetic flux passing through the inside of the inner peripheral side wall portion decreases, and magnetic flux leakage is likely to occur. The present invention has been completed as a result of intensive studies based on such knowledge.

[0016] The non-excitation operation type brake for a brake device according to one aspect of the present invention allows the rotation of the motor shaft when energized and blocks the rotation of the motor shaft when de-energized, and includes a casing, a fixed plate, an electromagnetic coil, an armature, a rotating side disk, and a pressing spring. The casing functions as a yoke and has a coil accommodating portion having a substantially U-shaped cross section and configured in an annular shape as a whole. The fixed plate is fixed to be separated from the casing in the axial direction of the motor shaft. The electromagnetic coil is accommodated in the coil accommodating portion. The armature is disposed between the fixed plate and the electromagnetic coil. The rotating side disk is disposed coaxially with the motor shaft between the fixed plate and the armature. The compression spring biases the armature away from the electromagnetic coil with respect to the axial direction of the motor shaft. The rotating disk is engaged with the motor shaft or a shaft that rotates synchronously with the motor shaft in such a way that it allows relative displacement of the motor shaft in the axial direction and prevents relative displacement of the motor shaft in the circumferential direction. In a non-excitation-operated brake for a brake device according to one aspect of the present invention, the casing has a substantially cylindrical shape and further includes an auxiliary yoke, which is fitted inside the coil housing and is separate from the coil housing.

[0017] In a non-excitation-operated brake for a brake device according to one aspect of the present invention, the coil housing portion comprises an inner circumferential side wall portion arranged radially inside the electromagnetic coil, an outer circumferential side wall portion arranged radially outside the electromagnetic coil, and a bottom wall portion connecting the end of the inner circumferential side wall portion and the end of the outer circumferential side wall portion in the radial direction of the motor shaft. Yes The thickness dimensions of the inner circumferential side wall, the outer circumferential side wall, and the bottom wall are made the same. doing .

[0018] In a non-excitation-operated brake for a brake device according to one aspect of the present invention, the casing is configured to include a casing body having the coil housing portion and the auxiliary yoke. doing . Furthermore, the coil housing portion has a substantially L-shaped cut-out piece on its bottom wall, and the auxiliary yoke has an outward-extending engaging piece at the end opposite to the armature in the axial direction of the motor shaft, extending radially outward, and the auxiliary yoke is prevented from coming off the casing body by the engagement of the cut-out piece and the outward-extending engaging piece as shown in the figure. It .

[0019] In a non-excitation-operated brake for a brake device according to one aspect of the present invention, the compression spring can be a coil spring and arranged radially inward of the auxiliary yoke. In this case, the auxiliary yoke may have an inwardly extending engaging piece at the end opposite to the armature in the axial direction of the motor shaft, and the compression spring may be positioned between the armature and the inwardly extending engaging piece in the axial direction of the motor shaft.

[0020] In one aspect of the present invention, a non-excitation-operated brake for a brake device may further include a stationary disc supported on the casing, which allows relative displacement of the motor shaft in the axial direction but prevents relative displacement of the motor shaft in the circumferential direction. Furthermore, a plurality of rotating discs may be provided, with the stationary discs positioned between adjacent rotating discs in the axial direction of the motor shaft.

[0021] A disc brake device according to one aspect of the present invention comprises a caliper having a cylinder positioned inward from the rotor in the axial direction of the rotor; a piston fitted into the cylinder; a rotation-to-linear motion conversion mechanism disposed within the cylinder and converting rotational motion into linear motion to push the piston toward the rotor; and a motor gear unit supported and fixed to the caliper and driving the rotation-to-linear motion conversion mechanism. Furthermore, the motor gear unit is configured to include an electric motor having a motor shaft, and a non-excitation-operated brake that allows the motor shaft to rotate when energized and prevents the motor shaft from rotating when de-energized. In a disc brake device according to one aspect of the present invention, a non-excitation-operated brake for a brake device according to one aspect of the present invention is used as the non-excitation-operated brake. [Effects of the Invention]

[0022] According to one aspect of the present invention, a non-excitation-operated brake for a braking device can suppress the occurrence of magnetic flux leakage and ensure sufficient magnetic attraction force to move the armature toward the electromagnetic coil. [Brief explanation of the drawing]

[0023] [Figure 1] Figure 1 is a front view of the disc brake device of the first embodiment, as seen from the outside of the vehicle body, in the position where it is attached to the suspension system. [Figure 2] Figure 2 is a rear view of the disc brake device of the first embodiment, as seen from the center of the vehicle body, in the position where it is attached to the suspension system. [Figure 3] Figure 3 is a plan view of the disc brake device of the first embodiment, as seen from above in Figure 1. [Figure 4] Figure 4 is a perspective view of the disc brake device of the first embodiment, seen from the outside of the vehicle body and radially outward. [Figure 5] Figure 5 is a perspective view of the disc brake device of the first embodiment, viewed from the center and radially outward side of the vehicle body. [Figure 6] Figure 6 is a cross-sectional view taken along line AA in Figure 1. [Figure 7] Figure 7 is a cross-sectional view taken along the line B-B in Figure 1. [Figure 8] Figure 8 is a front view of the motor gear unit removed from the disc brake device of the first embodiment, as seen from the outside of the vehicle body. [Figure 9] Figure 9 is a rear view of the motor gear unit removed from the disc brake device of the first embodiment, as seen from the center of the vehicle body. [Figure 10] Figure 10 is a rear view of the motor gear unit according to the first embodiment, showing the unit with the cover plate removed from the state shown in Figure 9. [Figure 11] Figure 11 is a partial cross-sectional view of a motor gear unit according to a first example of the embodiment. [Figure 12] Figure 12 is a perspective view showing a motor gear unit according to a first example of the embodiment, with the housing and non-excitation-operated brake omitted. [Figure 13] Figure 13 is a schematic diagram showing a reduction mechanism according to the first example of the embodiment. [Figure 14]Figure 14 shows a power distribution mechanism according to the first embodiment, viewed from the radially outer side of the support shaft. [Figure 15] Figure 15 is a perspective view showing a power distribution mechanism according to the first example of the embodiment. [Figure 16] Figure 16 is a view of a non-excitation-operated brake according to the first embodiment, taken out and viewed from the axial direction of the motor shaft. [Figure 17] Figure 17 is a view of a non-excitation-operated brake according to the first embodiment, taken out and viewed from the radially outer side of the motor shaft. [Figure 18] Figure 18 is a perspective view showing a non-excitation-operated brake according to the first example of the embodiment. [Figure 19] Figure 19 is a cross-sectional view along the CC line in Figure 16. [Figure 20] Figure 20 is an exploded perspective view showing a non-excitation-operated brake according to the first example of the embodiment. [Figure 21] Figure 21 is a schematic diagram of the casing constituting a non-excitation-operated brake according to the first embodiment, corresponding to the cross-section along line DD in Figure 19. [Modes for carrying out the invention]

[0024] [First example of an embodiment] A first example of the embodiment will be described using Figures 1 to 21.

[0025] [Overall configuration of the disc brake system] The disc brake system 1 in this example is an electrically operated parking brake type disc brake system, which combines the functions of a hydraulic service brake and an electrically operated parking brake.

[0026] The disc brake device 1 is a floating-type disc brake device and comprises a support 2, a caliper 3, a pair of pads 4a and 4b (outer pad 4a, inner pad 4b), two pistons 5a and 5b (first piston 5a, second piston 5b), two rotary-to-linear motion conversion mechanisms 6a and 6b (first rotary-to-linear motion conversion mechanism 6a, second rotary-to-linear motion conversion mechanism 6b), and a motor gear unit 7 including an electric motor 40 and an unexcited brake 42.

[0027] This example shows the present invention applied to a disc brake system incorporated into a relatively large vehicle. Therefore, the disc brake system 1 is equipped with two pistons 5a, 5b and two rotary-to-linear motion conversion mechanisms 6a, 6b. However, when applied to a disc brake system for a typical passenger car, it can be equipped with one piston and one rotary-to-linear motion conversion mechanism. Furthermore, it is possible to equip the system with three or more pistons and three or more rotary-to-linear motion conversion mechanisms.

[0028] The disc brake system 1 obtains braking force from the service brake by supplying brake oil (pressurized oil), which is a hydraulic fluid, to the first cylinder 20a and the second cylinder 20b provided in the caliper 3. In contrast, the disc brake system 1 obtains braking force from the parking brake by driving the first rotational linear motion conversion mechanism 6a and the second rotational linear motion conversion mechanism 6b by the motor gear unit 7, without using hydraulic fluid.

[0029] In the following description of the disc brake device 1, unless otherwise specified, axial, circumferential, and radial directions refer to the axial, circumferential, and radial directions of the disc-shaped rotor 8 (see Figure 7) that rotates with the wheel. The front-back direction in Figures 1, 2, 8, 9, and 10, the up-down direction in Figures 3 and 7, and the left-right direction in Figure 6 correspond to the axial direction, respectively. When mounted on the vehicle body, the central side of the vehicle body is called the axial inner side, and the outer side of the vehicle body is called the axial outer side. In addition, the up-down direction in Figures 1, 2, 6, 8, 9, 10, and 11, and the front-back direction in Figures 3 and 7 correspond to the circumferential direction, respectively, and also to the up-down direction when mounted on the vehicle body. Furthermore, the left-right direction in Figures 1-3 and 7-11, and the front-back direction in Figure 6, correspond to the radial direction. The left side of Figures 1, 3, 7, and 8, and the right side of Figures 2, 9, and 10 are radially outward, while the right side of Figures 1, 3, 7, and 8, and the left side of Figures 2, 9, and 10 are radially inward.

[0030] <support> Support 2 is a casting of an iron-based alloy such as cast iron, and comprises a support base 9 positioned axially inward of the rotor 8, an outer connecting portion 10 positioned axially outward of the rotor 8, and a pair of connecting arms 11a and 11b that axially connect the circumferential outer ends of the support base 9 and the circumferential outer ends of the outer connecting portion 10, respectively. Guide holes (not shown) that open axially inward are formed in the radially outer portions (rotor path portions) of the connecting arms 11a and 11b. Support 2 is fixed to the suspension system that constitutes the vehicle body using a plurality of mounting holes 12 (four in the illustrated example) formed in the radially inner portion of the support base 9.

[0031] In this example, with the support 2 fixed to the suspension system, the disc brake device 1 has one connecting arm 11a positioned on the upper side in the vertical direction, and the other connecting arm 11b positioned on the lower side in the vertical direction, as shown in Figures 1 and 2. However, when implementing the present invention, the assembly direction of the disc brake device is not particularly limited.

[0032] <Outer pads and inner pads> The outer pad 4a and inner pad 4b are positioned on both axial sides of the rotor 8. Specifically, the outer pad 4a is positioned on the axial outer side of the rotor 8 and is supported by the support 2 in a manner that allows for axial displacement. The inner pad 4b is positioned on the axial inner side of the rotor 8 and is supported by the support 2 in a manner that allows for axial displacement.

[0033] Each of the outer pad 4a and inner pad 4b comprises a lining (friction material) 13 and a metal backing plate (pressure plate) 14 that supports the back surface of the lining 13.

[0034] <Caliper> Caliper 3 is made of an aluminum alloy or an iron alloy and has an inverted U-shape. Caliper 3 has a pressing portion 15 on its axially outer side and a clamp base 16 on its axially inner side. Caliper 3 is also positioned radially outward of rotor 8 and has a bridge portion 17 that connects the pressing portion 15 and the clamp base 16 in the axial direction.

[0035] The clamp base 16 comprises a base body 18 and a pair of arms 19a and 19b extending circumferentially outward from the base body 18. The base body 18 has a first cylinder 20a and a second cylinder 20b inside, which are both substantially cylindrical spaces. The first cylinder 20a and the second cylinder 20b each have an opening on the axial outward side, but the opening on the axial inward side is closed by bottoms 21a and 21b.

[0036] A first piston 5a is fitted into the first cylinder 20a, and a second piston 5b is fitted into the second cylinder 20b. Each of the first piston 5a and the second piston 5b is made of carbon steel, such as S10C or S45C, and is constructed in a bottomed cylindrical shape.

[0037] Female splines 23a and 23b are provided on the inner circumferential surfaces of the first piston 5a and the second piston 5b. The portions between the outer circumferential surface of the first piston 5a and the inner circumferential surface of the first cylinder 20a, and between the outer circumferential surface of the second piston 5b and the inner circumferential surface of the second cylinder 20b, are sealed by annular piston seals 24a and 24b. The piston seals 24a and 24b are fitted into seal grooves 25a and 25b formed on the inner circumferential surfaces of the axially outer portions of the first cylinder 20a and the second cylinder 20b.

[0038] The axially outer portions of the first piston 5a and the second piston 5b are prevented from rotating relative to the backing plate 14 of the inner pad 4b by an anti-rotation mechanism (not shown). Piston boots 26a and 26b are stretched over the portions between the axially outer portion of the outer circumferential surface of the first piston 5a and the axially outer opening edge of the first cylinder 20a, and between the axially outer portion of the outer circumferential surface of the second piston 5b and the axially outer opening edge of the second cylinder 20b.

[0039] The caliper 3 is supported by the support 2 in a way that allows for axial displacement. To this end, the axially inner ends of the guide pins 27a and 27b are fixed to a pair of arms 19a and 19b that constitute the clamp base 16, respectively, and the axially outer ends or intermediate portions of the guide pins 27a and 27b are inserted into guide holes formed in a pair of connecting arms 11a and 11b that constitute the support 2, allowing for relative axial displacement. Boots 28a and 28b are also placed between the outer circumferential surfaces of the guide pins 27a and 27b and the openings of the guide holes.

[0040] <Rotational-to-linear motion conversion mechanism> The first rotation-to-linear motion conversion mechanism 6a and the second rotation-to-linear motion conversion mechanism 6b, as shown in Figures 6 and 7, are lead screw mechanisms (ball screw devices) that convert rotational motion into linear motion and change the overall length in the axial direction during operation. They each consist of a spindle 29a, 29b, which is a rotating member, a nut 30a, 30b, which is a linear member, and a plurality of balls 31a, 31b. The first rotation-to-linear motion conversion mechanism 6a pushes the first piston 5a toward the rotor 8, and the second rotation-to-linear motion conversion mechanism 6b pushes the second piston 5b toward the rotor 8. When implementing the present invention, a sliding lead screw device can also be used in which the spindle and nut are in direct contact without the balls.

[0041] The spindles 29a and 29b have helical axial ball screw grooves 32a and 32b on their outer circumferential surfaces, extending from the tip (axially outer portion) to the middle portion. The base portions (axially inner portions) of the spindles 29a and 29b are inserted through through holes 33a and 33b formed in the bottom portions 21a and 21b of the clamp base 16, and are connected to the tips of the first output shaft 68 and the second output shaft 69, which will be described later, in a way that prevents relative rotation.

[0042] Annular support rings 34a and 34b are fitted onto the base portions of spindles 29a and 29b in a manner that prevents relative rotation. Thrust bearings 35a and 35b are positioned between the axial inner surfaces of the support rings 34a and 34b and the axial outer surfaces of the bottom portions 21a and 21b. This allows the axial load (axial force) acting on spindles 29a and 29b to be supported by the bottom portions 21a and 21b, while also enabling relative rotation of spindles 29a and 29b with respect to the bottom portions 21a and 21b.

[0043] Nuts 30a and 30b have helical nut-side ball screw grooves 36a and 36b on their inner circumferential surfaces and male splines 37a and 37b on their outer circumferential surfaces. When nut 30a is positioned inside the first piston 5a, its male spline 37a is spline-engaged with the female spline 23a provided on the first piston 5a. Similarly, when nut 30b is positioned inside the second piston 5b, its male spline 37b is spline-engaged with the female spline 23b provided on the second piston 5b. As a result, nut 30a is engaged with the first piston 5a in a way that allows for relative axial displacement but prevents relative rotation, and nut 30b is engaged with the second piston 5b in a way that allows for relative axial displacement but prevents relative rotation.

[0044] Multiple balls 31a and 31b are rotatably arranged inside a helical load path formed between the shaft-side ball screw grooves 32a and 32b and the nut-side ball screw grooves 36a and 36b. The start and end points of the load path are connected by circulating components 38a and 38b fixed to the nuts 30a and 30b.

[0045] In this example, the first rotation-to-linear motion conversion mechanism 6a and the second rotation-to-linear motion conversion mechanism 6b move the nuts 30a and 30b in the axial direction by rotating the spindles 29a and 29b. Specifically, when the spindles 29a and 29b are rotated in the forward direction, the nuts 30a and 30b are moved in a direction toward the rotor 8 (axially outward). Conversely, when the spindles 29a and 29b are rotated in the reverse direction, the nuts 30a and 30b are moved toward the rotor 8 (axially inward).

[0046] <Motor Gear Unit> The motor gear unit (MGU, electric drive unit) 7 is for electrically driving the first rotary-to-linear motion conversion mechanism 6a and the second rotary-to-linear motion conversion mechanism 6b, and comprises a housing 39, an electric motor 40, a reduction mechanism 41, and a non-excitation-operated brake 42. The non-excitation-operated brake 42 corresponds to the non-excitation-operated brake for the brake device described in the claims.

[0047] "housing" The housing 39 is made of synthetic resin or metal and is supported and fixed to the clamp base 16 that constitutes the caliper 3. Specifically, the housing 39 is supported and fixed axially inward of the clamp base 16 using mounting bolts 44a and 44b that pass through a pair of mounting flange portions 43a and 43b provided on the outer circumferential surface of the clamp base 16, and a mounting bolt 44c that passes axially through the radially inward portion of the housing 39.

[0048] The housing 39 consists of a housing body 45, a sealing plate portion 46, and a cover 47. The housing body 45 includes a motor housing portion 48, a gear housing portion 49, and a brake housing portion 50, each of which is hollow.

[0049] The motor housing 48 is the part that houses the electric motor 40 inside. In the illustrated example, the motor housing 48 has a cylindrical shape with an inner diameter slightly larger than the outer diameter of the motor body 53, which will be described later and constitutes the electric motor 40.

[0050] The gear housing 49 is the part that houses the reduction mechanism 41 inside. In the illustrated example, the gear housing 49 is configured in a housing that has a larger volume than the motor housing 48.

[0051] As shown in Figure 8, the gear housing 49 Axial outer surface The side wall portion 51 that constitutes the gear housing has two insertion holes 52a and 52b into which the base ends of the spindles 29a and 29b, respectively, can be inserted. The central axes of the insertion holes 52a and 52b are arranged in the axial direction. The axially inner opening of the gear housing portion 49 is closed by a sealing plate portion 46.

[0052] The brake housing 50 is the part that houses the non-excitation-operated brake 42 inside. In the illustrated example, the brake housing 50 is configured in the shape of a rectangular casing. The upper opening of the brake housing 50 is closed by a cover 47.

[0053] Electric motor The electric motor 40 is located inside the motor housing 48. The electric motor 40 has a motor body 53 and a motor shaft 54. Figure 13 schematically shows these components (motor body 53 and motor shaft 54).

[0054] The motor body 53 comprises a cylindrical motor housing 55 and a rotor and stator (not shown) arranged inside the motor housing 55. The rotor is supported in the axial middle portion of the motor shaft 54. The stator is arranged around the rotor and supported inside the motor housing 55.

[0055] The axial ends of the motor shaft 54 ​​protrude from the motor body 53 in both axial directions. The motor shaft 54 ​​has a axial first connection portion 56 connected to the reduction mechanism 41 at one axial end protruding from the motor body 53. The motor shaft 54 ​​also has a axial second connection portion 57 connected to the non-excitation type brake 42 at the other axial end protruding from the motor body 53. The electric motor 40 rotates the motor shaft 54 ​​by a predetermined angle in a predetermined direction based on a command signal from a control device (not shown).

[0056] 《Reduction mechanism》 The reduction gear 41 increases the torque (power) of the electric motor 40 and transmits it to the first rotary-to-linear motion converter 6a and the second rotary-to-linear motion converter 6b. Therefore, the reduction gear 41 transmits the rotation of the electric motor 40 to the two spindles 29a and 29b, respectively. The reduction gear 41 is housed inside the gear housing 49.

[0057] The reduction gear 41 includes a worm reduction gear 58, a power distribution mechanism (differential) 59, and a plurality of gears (spur gears) 60a to 60e. Figure 13 schematically shows some of the components of the reduction gear 41 (worm reduction gear 58, power distribution mechanism 59, and the plurality of gears 60a to 60e).

[0058] (Worm gear reducer) The worm gear reduction mechanism 58 is connected to the first connection portion 56 of the motor shaft 54 ​​that constitutes the electric motor 40. The worm gear reduction mechanism 58 consists of a worm 61 and a worm wheel 62 and does not have a self-locking function. Therefore, the worm gear reduction mechanism 58 in this example can not only transmit the rotation of the electric motor 40 to the first rotary-to-linear motion conversion mechanism 6a and the second rotary-to-linear motion conversion mechanism 6b, but can also transmit the rotation input in reverse from the first rotary-to-linear motion conversion mechanism 6a and the second rotary-to-linear motion conversion mechanism 6b to the motor shaft 54 ​​of the electric motor 40.

[0059] The worm 61 has worm teeth 63 in the axial middle portion of its outer circumferential surface and is arranged coaxially with the motor shaft 54 ​​of the electric motor 40. The other axial end (base end) of the worm 61 is fixed to the first connection portion 56 of the motor shaft 54 ​​so as not to rotate relative to it. The one axial end of the worm 61 is rotatably supported inside the gear housing 49 via a bearing (not shown).

[0060] The worm wheel 62 has wheel teeth 64 on its outer circumference. The wheel teeth 64 mesh with the worm teeth 63 provided on the worm 61. The worm wheel 62 is externally fitted and fixed to a first intermediate shaft 65, which is rotatably supported inside the gear housing 49, so as to be unable to rotate relative to it. The first intermediate shaft 65 is arranged substantially parallel to the central axes of the spindle 29a of the first rotary-to-linear motion conversion mechanism 6a and the spindle 29b of the second rotary-to-linear motion conversion mechanism 6b. Therefore, the rotational axis of the worm wheel 62 is arranged substantially parallel to the central axes of the spindles 29a and 29b. Note that "substantially parallel" includes not only perfectly parallel but also substantially parallel.

[0061] Inside the gear housing 49, in addition to the first intermediate shaft 65, a second intermediate shaft 66, a support shaft 67, a first output shaft 68, and a second output shaft 69 are supported. The second intermediate shaft 66, support shaft 67, first output shaft 68, and second output shaft 69 are arranged substantially parallel to the first intermediate shaft 65. The first intermediate shaft 65, second intermediate shaft 66, support shaft 67, first output shaft 68, and second output shaft 69 constitute a reduction gear mechanism 41, and of these, the support shaft 67 in particular constitutes a power distribution mechanism 59.

[0062] A first gear 60a is fitted and fixed to the first intermediate shaft 65 in a manner that prevents relative rotation, on a portion that is axially offset from the worm wheel 62. The first gear 60a has fewer teeth than the wheel teeth 64 and meshes with a second gear 60b, which is fitted and fixed to the second intermediate shaft 66 in a manner that prevents relative rotation. A third gear 60c, which has fewer teeth than the second gear 60b, is fitted and fixed to the second intermediate shaft 66 in a manner that prevents relative rotation, on a portion that is axially offset from the second gear 60b. The third gear 60c meshes with an input carrier 73, which will be described later and constitutes the power distribution mechanism 59. Therefore, the power distribution mechanism 59 is located downstream of the worm reduction mechanism 58 with respect to the power transmission direction of the electric motor 40.

[0063] The fourth gear 60d, which is the final gear, is externally fitted and fixed to the first output shaft 68, and the fifth gear 60e, which is the final gear, is externally fitted and fixed to the second output shaft 69. The fourth gear 60d meshes with the first output member 76, which will be described later and constitutes the power distribution mechanism 59, and the fifth gear 60e meshes with the second output member 77, which will be described later and constitutes the power distribution mechanism 59.

[0064] The axial outer ends of the first output shaft 68 and the second output shaft 69 are provided with engagement holes (serration holes) 70a and 70b, respectively. In this example, the axial inner ends (base ends) of the spindles 29a and 29b, which constitute the first rotary-to-linear motion conversion mechanism 6a and the second rotary-to-linear motion conversion mechanism 6b, are engaged with the engagement holes 70a and 70 in a manner that prevents relative rotation. This connects the first output shaft 68 and the spindle 29a coaxially and prevents relative rotation. Similarly, the second output shaft 69 and the spindle 29b are connected coaxially and prevent relative rotation. For this reason, the rotational axes of the final gears, the fourth gear 60d and the fifth gear 60e, are arranged substantially parallel (coaxially) to the central axes of the spindles 29a and 29b. When implementing the present invention, the first output shaft and the spindle and / or the second output shaft and the spindle can be configured as a single unit, and the final gears can be directly connected to the spindle.

[0065] (power distribution mechanism) The power distribution mechanism 59 is positioned between the third gear 60c and the final gears, the fourth gear 60d and the fifth gear 60e. The power distribution mechanism 59 has the function of distributing and transmitting the power input from the third gear 60c to the fourth gear 60d and the fifth gear 60e.

[0066] Specifically, the power distribution mechanism 59 distributes power to the fourth gear 60d and the fifth gear 60e according to the magnitude of the rotational load (ease of rotation) of the spindles 29a and 29b. This prevents a difference from occurring between the force with which the first piston 5a presses the inner pad 4b by the first rotational linear motion conversion mechanism 6a and the force with which the second piston 5b presses the inner pad 4b by the second rotational linear motion conversion mechanism 6b, regardless of the difference in efficiency between the first rotational linear motion conversion mechanism 6a and the second rotational linear motion conversion mechanism 6b.

[0067] The power distribution mechanism 59 has a support shaft 67 and a gear train 71 arranged around the support shaft 67. The power distribution mechanism 59 is supported by the housing 39 by supporting and fixing the axial ends of the support shaft 67 to the housing 39, and is located inside the gear housing 49.

[0068] The gear train 71 consists of multiple gears (spur gears) and is unitized (sub-assembled), making it possible to handle it as a single part.

[0069] The gear train 71 consists of an input carrier 73, a first intermediate gear 74 and a second intermediate gear 75, and a first output member 76 and a second output member 77. The input carrier 73, the first output member 76 and the second output member 77 are also gears having teeth on their outer surfaces.

[0070] The input carrier 73 has a pair of support rings 78a and 78b, each having an annular shape, and a number of pins 79a and 79b (a total of six in the illustrated example) that are stretched between the pair of support rings 78a and 78b. The pair of support rings 78a and 78b are connected to each other by the number of pins 79a and 79b. One support ring 78a has teeth 73a on its outer surface that mesh with a third gear 60c, and a second output member 77 is inserted inside it so as to be able to rotate relative to it. A first output member 76 is inserted inside the other support ring 78b so as to be able to rotate relative to it. The pins 79a and 79b are arranged parallel to the support shaft 67. As will be described later, since the support shaft 67 is inserted inside the first output member 76 and the second output member 77, the input carrier 73 is rotatably supported around the support shaft 67 via the first output member 76 and the second output member 77.

[0071] The first intermediate gear 74 and the second intermediate gear 75 are rotatably supported with respect to the input carrier 73. Specifically, the first intermediate gear 74 and the second intermediate gear 75 are rotatably supported around pins 79a and 79b, and are positioned between a pair of support rings 78a and 78b. The first intermediate gear 74 and the second intermediate gear 75 mesh with each other.

[0072] The first output member 76 and the second output member 77 are arranged coaxially with respect to each other, separated in the axial direction. The first output member 76 is rotatably supported around the axially inner portion of the support shaft 67, and the second output member 77 is rotatably supported around the axially outer portion of the support shaft 67.

[0073] The first output member 76 is configured in a hollow cylindrical shape and has input teeth 76a and output teeth 76b on its outer circumferential surface. The input teeth 76a mesh with the first intermediate gear 74. In contrast, the output teeth 76b mesh with the fourth gear 60d. Therefore, the rotation of the first output member 76 is transmitted to the first output shaft 68 through the meshing portion between the output teeth 76b and the fourth gear 60d.

[0074] The second output member 77 is configured in a hollow cylindrical shape and has input teeth 77a and output teeth 77b on its outer circumferential surface. The input teeth 77a mesh with the second intermediate gear 75. In contrast, the output teeth 77b mesh with the fifth gear 60e. Therefore, the rotation of the second output member 77 is transmitted to the second output shaft 69 through the meshing portion between the output teeth 77b and the fifth gear 60e.

[0075] In this example, the power distribution mechanism 59 includes a biasing member (not shown) between the first output member 76 and the second output member 77 to prevent relative rotation between the first output member 76 and the second output member 77 when the braking force from the parking brake is released (during differential pressure reduction). When implementing the present invention, a coupling may also be provided to maintain the orientation of the biasing member and to prevent localized wear of the first output member 76 and the second output member 77 due to sliding contact with the biasing member.

[0076] In this example, when obtaining braking force from the parking brake (during pressurized differential operation), the power distribution mechanism 59 causes the input carrier 73 to rotate (rotate) around the support shaft 67, thereby causing the first intermediate gear 74 and the second intermediate gear 75 to revolve.

[0077] Furthermore, when the magnitude of the rotational load on the first output member 76 and the second output member 77, that is, the magnitude of the rotational load (ease of rotation) on the spindles 29a and 29b, is the same, the first intermediate gear 74 and the second intermediate gear 75 remain meshed with each other and revolve only without rotating on their own axes, transmitting rotation to the first output member 76 and the second output member 77. For this reason, the first output member 76 meshed with the first intermediate gear 74 and the second output member 77 meshed with the second intermediate gear 75 both rotate in the same direction at the same speed. When the magnitude of the rotational load on the spindles 29a and 29b is the same, for example, it refers to a state in which the tips of the nuts 30a and 30b do not press against the first piston 5a and the second piston 5b, and the spindles 29a and 29b are rotating without load, or a state of slight pressure in which the tips of the nuts 30a and 30b have just begun to press against the first piston 5a and the second piston 5b.

[0078] In contrast, when the magnitudes of the rotational loads of the first output member 76 and the second output member 77, that is, the magnitudes of the rotational loads of the spindles 29a and 29b, are different, the first intermediate gear 74 and the second intermediate gear 75 rotate on their own axis as well as revolve while remaining meshed with each other, transmitting rotation to one or both of the first output member 76 and the second output member 77. The case where the magnitudes of the rotational loads of the spindles 29a and 29b are different occurs when, due to differences in efficiency between the first rotary-to-linear motion conversion mechanism 6a and the second rotary-to-linear motion conversion mechanism 6b, the first piston 5a and the second piston 5b do not press the inner pad 4b simultaneously, and the timing of when the first piston 5a and the second piston 5b press the inner pad 4b is staggered.

[0079] For example, if the first piston 5a presses the inner pad 4b before the second piston 5b, the rotational load of the spindle 29a constituting the first rotary-to-linear motion conversion mechanism 6a will be greater than the rotational load of the spindle 29b constituting the second rotary-to-linear motion conversion mechanism 6b. In this case, the power distribution mechanism 59 distributes and transmits the rotation of the input carrier 73 to the first output member 76 and the second output member 77 such that the rotational speed of the first output member 76 is less than the rotational speed of the second output member 77. Conversely, if the second piston 5b presses the inner pad 4b before the first piston 5a, the rotational load of the spindle 29a constituting the first rotary-to-linear motion conversion mechanism 6a will be less than the rotational load of the spindle 29b constituting the second rotary-to-linear motion conversion mechanism 6b. In this case, the power distribution mechanism 59 distributes and transmits the rotation of the input carrier 73 to the first output member 76 and the second output member 77 such that the rotational speed of the first output member 76 is greater than the rotational speed of the second output member 77.

[0080] Furthermore, in this example, when the braking force from the parking brake is released (during depressurization differential operation), the power distribution mechanism 59 prevents relative rotation between the first output member 76 and the second output member 77 by the action of the biasing member, and allows both the first output member 76 and the second output member 77 to rotate simultaneously in the opposite direction to that during pressurized operation. As a result, both the pressing force on the inner pad 4b by the first piston 5a and the pressing force on the inner pad 4b by the second piston 5b can be set to zero.

[0081] 《Non-excitation type brake》 As shown in Figure 11, the de-excitation type brake 42 is housed in a brake housing 50 that constitutes the housing 39 and is connected to a second connection 57 of the motor shaft 54 ​​that constitutes the electric motor 40. Specifically, the de-excitation type brake 42 is connected to the second connection 57 via a connecting shaft 80. The connecting shaft 80 is connected to the second connection 57 in a way that prevents relative rotation. The de-excitation type brake 42 is a friction brake and has the function of allowing the motor shaft 54 ​​to rotate when the automobile engine is running and energized, and preventing the rotation of the motor shaft 54 ​​when the automobile engine is stopped and energized. In the following description of the de-excitation type brake 42, axial direction, radial direction, and circumferential direction refer to the axial direction, radial direction, and circumferential direction with respect to the motor shaft 54 ​​unless otherwise specified.

[0082] The non-excitation type brake 42 includes a casing 81, a fixed plate 82, an electromagnetic coil 83, an armature (pressure plate) 84, a plurality of rotating discs 85 (three in the illustrated example), a plurality of stationary discs 86 (two in the illustrated example), and a pressure spring 87.

[0083] (Casing) The casing 81 comprises a casing body 89 and an auxiliary yoke 90 separate from the casing body 89. In this example, the casing 81 is positioned on the other axial side (upper side in Figure 19) relative to the armature 84. Therefore, with respect to the casing 81, the end located on the opposite side of the armature 84 in the axial direction refers to the end on the other axial side (upper end in Figure 19).

[0084] The casing body 89 is made by press-forming (deep-drawing) a magnetic metal plate and has a coil housing portion 91 and a mounting flange portion 92.

[0085] The coil housing section 91 has a roughly U-shaped cross-section that covers the electromagnetic coil 83 from three sides, and the entire structure is ring-shaped. The coil housing section 91 functions as a yoke. That is, when the electromagnetic coil 83 is energized, the coil housing section 91 forms a magnetic circuit, and magnetic flux passes through its interior.

[0086] The coil housing 91 has an inner circumferential wall portion 93 having a cylindrical shape and positioned radially inside the electromagnetic coil 83, an outer circumferential wall portion 94 having a cylindrical shape and positioned radially outside the electromagnetic coil 83, and a bottom wall portion 95 having a ring-shaped plate shape that radially connects the other axial end of the inner circumferential wall portion 93 and the other axial end of the outer circumferential wall portion 94. The inner circumferential wall portion 93 and the outer circumferential wall portion 94 are arranged coaxially. The coil housing 91 is open on one side in the axial direction.

[0087] In this example, the casing body 89 is made by press-forming a magnetic metal plate of a constant thickness, so the thickness dimension t of the inner circumferential side wall portion 93 is i The thickness dimension t of the outer peripheral wall portion 94 o And the thickness dimension t of the bottom wall portion 95 b This means that they are the same size (t i =t o =t b ). Note that "same thickness dimension" includes cases where they are substantially the same.

[0088] The coil housing section 91 has cut-out pieces 96 at multiple locations (two locations in the illustrated example) in the circumferential direction of the bottom wall section 95. In this example, the bottom wall section 95 has two cut-out pieces 96. The two cut-out pieces 96 are located on opposite sides of the bottom wall section 95 in the diametrical direction. The cut-out pieces 96 are formed by press-forming the bottom wall section 95 and have a substantially L-shape. The cut-out piece 96 has an upright portion 96a that is erected in the axial direction and a claw portion 96b that is bent at substantially a right angle radially inward from the tip of the upright portion 96a. The claw portion 96b is formed at the tip of the upright portion 96a after the auxiliary yoke 90 is fitted inside the radially inward side of the coil housing section 91. When implementing the present invention, the number of cut-out pieces can be changed as appropriate.

[0089] The mounting flange portion 92 is provided at one axial end of the outer peripheral side wall portion 94 that constitutes the coil housing portion 91, and extends radially outward. The mounting flange portion 92 is positioned approximately perpendicular to the outer peripheral side wall portion 94. The mounting flange portion 92 has an annular shape and has through holes 92a at multiple locations in the circumferential direction (three locations in the illustrated example) through which rivets 100, described later, can be inserted.

[0090] The auxiliary yoke 90 has a substantially cylindrical shape and is fitted and fixed inside the coil housing portion 91 that constitutes the casing body 89, and functions as a yoke together with the coil housing portion 91.

[0091] The auxiliary yoke 90 is manufactured by press-forming a magnetic metal plate of the same type as the magnetic metal plate that constitutes the casing body 89, and has a cylindrical portion 97, a plurality (two in the illustrated example) of outward engaging pieces 98, and a plurality (four in the illustrated example) of inward engaging pieces 99. In addition, when implementing the present invention, the auxiliary yoke may also be manufactured from a magnetic metal plate of a different type than that of the casing body.

[0092] The cylindrical portion 97 has a cylindrical shape and is fitted inside the coil accommodating portion 91. In this example, the cylindrical portion 97 is press-fitted inside the coil accommodating portion 91. For this reason, the cylindrical portion 97 has an outer diameter dimension slightly larger than the inner diameter dimension of the inner peripheral side wall portion 93 that constitutes the coil accommodating portion 91. The outer peripheral surface of the cylindrical portion 97 is in close contact with the inner peripheral surface of the inner peripheral side wall portion 93 over the entire circumference.

[0093] The axial dimension of the cylindrical portion 97 is substantially the same as the axial dimension of the inner peripheral side wall portion 93. In this example, the thickness dimension t of the cylindrical portion 97 a is set as follows. That is, as shown in FIG. 21 to When the coil accommodating portion 91 and the auxiliary yoke 90 are cut in a virtual plane orthogonal to the central axis of the motor shaft 54, the cross-sectional area S of the cylindrical portion 97 a and the cross-sectional area S of the inner peripheral side wall portion 93 i The sum (S a +S i ) is the cross-sectional area S of the outer peripheral side wall portion 94 o or more (S a +SSince i ≧S o ), the thickness dimension t of the cylindrical portion 97 a is geometrically determined so that. However, when implementing the present invention, the thickness dimension of the cylindrical portion may be set so that the sum of the cross-sectional area of the cylindrical portion and the cross-sectional area of the inner diameter side wall portion is smaller or larger than the cross-sectional area of the outer peripheral side wall portion. For example, the thickness dimension of the cylindrical portion is such that the sum (S a +S i ) is preferably set in the range of 80% to 200% of the cross-sectional area (S О ) of the outer peripheral side wall portion.

[0094] The outward-facing engaging piece 98 is provided at the other axial end of the cylindrical portion 97 and extends radially outward. The outward-facing engaging piece 98 is configured as a substantially rectangular flat plate and is positioned substantially perpendicular to the cylindrical portion 97. In this example, the auxiliary yoke 90 has two outward-facing engaging pieces 98. The two outward-facing engaging pieces 98 are positioned on opposite sides of the cylindrical portion 97 in the radial direction. When implementing the present invention, the number of outward-facing engaging pieces may be the same as the number of cut-out pieces of the casing body and can be changed as appropriate.

[0095] The outward engaging piece 98 engages axially with a cut-up piece 96 provided on the bottom wall portion 95 that constitutes the casing body 89. Specifically, the outward engaging piece 98 is fitted into the coil housing portion 91 and mechanically engages with a claw portion 96b formed at the tip of the upright portion 96a, with the outward engaging piece 98 and the upright portion 96a aligned in phase. The engagement between the outward engaging piece 98 and the claw portion 96b of the cut-up piece 96 prevents the auxiliary yoke 90 from coming loose from the casing body 89 in the other axial direction.

[0096] The outward engaging piece 98 has an engaging recess 98a on the side facing the claw portion 96b on the axial side opposite to the claw portion 96b. When the outward engaging piece 98 and the claw portion 96b are engaged, the circumferential side of the engaging recess 98a is positioned opposite the claw portion 96b. This prevents relative rotation of the auxiliary yoke 90 with respect to the casing body 89. Furthermore, by forming the engaging recess 98a on the outward engaging piece 98, the axial dimension of the upright portion 96a constituting the cut-up piece 96 can be shortened, and the radial dimension of the claw portion 96b can be increased, thus ensuring a large radial engagement allowance between the outward engaging piece 98 and the claw portion 96b.

[0097] The inward engaging piece 99 has a substantially L-shape and is provided at the other axial end of the cylindrical portion 97. The inward engaging piece 99 has an axial plate portion 99a extending axially from the other axial end of the cylindrical portion 97 and a radial plate portion 99b extending radially inward from the tip of the axial plate portion 99a. In this example, the auxiliary yoke 90 has four inward engaging pieces 99. The four inward engaging pieces 99 are arranged at equal intervals with respect to the circumference. The outward engaging piece 98 is positioned between a pair of adjacent inward engaging pieces 99 in the circumference. When implementing the present invention, the inward engaging pieces can also be composed only of radially extending portions. Furthermore, the number of inward engaging pieces can be two or more and can be changed as appropriate.

[0098] (Fixing plate) The fixing plate 82 is made of metal and has a hollow triangular shape. The fixing plate 82 is fixed to the casing body 89 at an axial distance. Specifically, the fixing plate 82 is fixed to the mounting flange portion 92 of the casing body 89 using multiple rivets 100 (three in the illustrated example). For this purpose, the fixing plate 82 has through holes 82a at multiple locations in the circumferential direction on the radially outer part through which the rivets 100 can be inserted. With the casing body 89 and the fixing plate 82 fixed by the rivets 100, cylindrical spacers 101 are fitted around the rivets 100. In other words, the spacers 101 are sandwiched between the casing body 89 and the fixing plate 82. For this reason, the fixing plate 82 is positioned at an axial distance from the casing body 89 by the length of the spacers 101.

[0099] The fixing plate 82 has mounting holes 82b at multiple locations in the circumferential direction on its radially outer side. The fixing plate 82 is fixed to the brake housing 50 that constitutes the housing 39 by multiple bolts (not shown) inserted through the mounting holes 82b.

[0100] (Electromagnetic coil) The electromagnetic coil 83 is configured in an annular shape and is housed inside the coil housing portion 91 that constitutes the casing 81. In this example, the electromagnetic coil 83 consists of an electric wire 102 and an annular bobbin 103 around which the electric wire 102 is wound. When energized, the electromagnetic coil 83 generates a magnetic field around it in the direction indicated by arrow X in Figure 19 (or in the opposite direction to arrow X).

[0101] (Armature) The armature 84 is made of a magnetic metal plate and is configured as an annular plate. The armature 84 is positioned between the fixing plate 82 and the electromagnetic coil 83 and covers the opening on one axial side of the coil housing 91 in which the electromagnetic coil 83 is housed. When the electromagnetic coil 83 is energized, the armature 84, together with the coil housing 91 and the auxiliary yoke 90, forms a magnetic circuit.

[0102] The armature 84 is supported relative to the casing 81 in such a way that it can be displaced axially but not circumferentially. For this purpose, the armature 84 has rivets 100 inserted through holes 84a provided at its radially outer end.

[0103] (Rotating disc) The rotating disk 85 is positioned coaxially with the motor shaft 54 ​​between the fixed plate 82 and the armature 84. The rotating disk 85 has a disc shape and a spline hole 85a in its radial center. In this example, multiple rotating disks 85 are provided (three in the illustrated example).

[0104] The rotating disk 85 engages with the connecting shaft 80 in a way that allows relative displacement in the axial direction but prevents relative displacement in the circumferential direction, by spline-engaging the spline hole 85a with the male spline portion 80a provided on the outer circumferential surface of the connecting shaft 80. Therefore, the rotating disk 85 can rotate in synchronization with the motor shaft 54.

[0105] (Static disk) The stationary disks 86 are arranged alternately with the rotating disks 85 in the axial direction. In this example, there are multiple stationary disks 86 (two in the illustrated example), and they are arranged between adjacent rotating disks 85 in the axial direction.

[0106] The stationary disk 86 has an annular shape, a through hole 86a in its radial center through which the connecting shaft 80 can be inserted, and bifurcated engaging protrusions 86b at multiple locations (three in the illustrated example) in the circumferential direction on its outer edge.

[0107] The stationary disk 86 is supported relative to the casing 81 in such a way that it can be displaced in the axial direction but cannot be displaced in the circumferential direction, by engaging its engaging projection 86b with the spacer 101. Therefore, the stationary disk 86 does not rotate even when the motor shaft 54 ​​rotates.

[0108] (Compression spring) The compression spring 87 presses the armature 84 toward one axial direction (the lower side in Figure 19), which is away from the electromagnetic coil 83 in the axial direction.

[0109] The compression spring 87 is a coil spring and is positioned radially inward of the auxiliary yoke 90. The compression spring 87 is positioned between the armature 84 and the inward engaging piece 99 provided on the auxiliary yoke 90 in an axially compressed state. In other words, the compression spring 87 elastically braces between the armature 84 and the inward engaging piece 99. This causes the compression spring 87 to bias the armature 84 axially away from the electromagnetic coil 83.

[0110] [Explanation of operation of non-excitation type brakes] In this example, the non-excitation type brake 42 forms a magnetic circuit in the casing 81 and armature 84 arranged around the electromagnetic coil 83 when the electromagnetic coil 83 is energized. Specifically, when the electromagnetic coil 83 is energized, a magnetic circuit is formed in the coil housing 91, auxiliary yoke 90, and armature 84. This causes the armature 84 to move toward the electromagnetic coil 83 against the elasticity of the compression spring 87 (magnetic attraction). In other words, the armature 84 elastically compresses and deforms the compression spring 87. As a result, the rotating disc 85 is not pressed against the fixed plate 82 and / or the stationary disc 86 by the armature 84, and the rotation of the motor shaft 54 ​​is permitted.

[0111] In contrast, when the electromagnetic coil 83 is de-energized, no magnetic circuit is formed in the coil housing 91, auxiliary yoke 90, and armature 84, as it is when energized. As a result, the rotating disk 85 is pressed against the fixed plate 82 and / or the stationary disk 86 by the armature 84, and frictionally engages with these fixed plate 82 and / or the stationary disk 86. This prevents the motor shaft 54 ​​from rotating.

[0112] [Explanation of disc brake system operation] When the service brake is activated by the disc brake device 1 in this example, brake fluid is supplied to the first cylinder 20a and the second cylinder 20b provided in the caliper 3 through an oil passage (not shown). This pushes the first piston 5a and the second piston 5b out of the first cylinder 20a and the second cylinder 20b, pressing the inner pad 4b against the axially inner surface of the rotor 8. The reaction force associated with this pressing displaces the caliper 3 axially inward relative to the support 2. Then, the pressing portion 15 of the caliper 3 presses the outer pad 4a against the axially outer surface of the rotor 8. As a result, braking force is obtained by the friction acting on the contact surface between the pair of pads 4a and 4b and the rotor 8. In this way, the disc brake device 1 obtains the braking force of the service brake by pushing out the first piston 5a and the second piston 5b by introducing brake fluid.

[0113] When the parking brake is activated by the disc brake device 1, the electric motor 40 constituting the motor gear unit 7 is energized, and the spindle 29a constituting the first rotational linear motion conversion mechanism 6a and the spindle 29b constituting the second rotational linear motion conversion mechanism 6b are rotated in the forward direction via the reduction mechanism 41. This moves the nuts 30a and 30b outward in the axial direction. Then, the first piston 5a and the second piston 5b are pushed toward the rotor 8, pressing the inner pad 4b against the axially inner surface of the rotor 8. In addition, the reaction force accompanying the pressing displaces the caliper 3 axially inward relative to the support 2. Then, the pressing portion 15 of the caliper 3 presses the outer pad 4a against the axially outer surface of the rotor 8. As a result, braking force is obtained by the friction acting on the contact surface between the pair of pads 4a and 4b and the rotor 8. In this way, the disc brake device 1 obtains the braking force of the parking brake by using the motor gear unit 7 to push the first piston 5a and the second piston 5b.

[0114] Furthermore, when the automobile engine is stopped and power is cut off to the electric motor 40, the power supply to the electromagnetic coil 83 constituting the de-excitation type brake 42 is also cut off. As a result, the de-excitation type brake 42 can prevent the rotation of the motor shaft 54. In other words, it prevents the first piston 5a and the second piston 5b from retracting, and keeps the inner pad 4b and the outer pad 4a pressed against the axial side of the rotor 8. Therefore, the disc brake device 1 in this example can maintain braking force from the parking brake even when power is cut off to the electric motor 40.

[0115] With the non-excitation type brake 42 incorporated into the disc brake device 1 of this example, the occurrence of magnetic flux leakage can be suppressed, and sufficient magnetic attraction force can be secured to move the armature 84 toward the electromagnetic coil 83. In other words, the non-excitation type brake 42 in this example consists of a casing 81 comprising a casing body 89 equipped with a coil housing 91 that functions as a yoke, and an auxiliary yoke 90, which is fitted inside the coil housing 91 and is separate from the casing body 89. By manufacturing the casing body 89 by press-forming a magnetic metal plate, the thickness dimension t of the inner circumferential side wall portion 93 can be made. i and the thickness dimension t of the outer peripheral wall portion 94 o Even when these conditions are the same, magnetic flux that cannot pass through the interior of the inner circumferential wall portion 93 (that leaks out from the inner circumferential wall portion 93) can pass through the interior of the cylindrical portion 97 of the auxiliary yoke 90. In other words, by fitting the auxiliary yoke 90 inside the inner circumferential wall portion 93, the thickness dimension t of the inner circumferential wall portion 93 is achieved. i The thickness dimension t of the cylindrical part 97 a This effectively provides the same effect as increasing the size by that amount. Therefore, with the de-excitation type brake 42 of this example, magnetic flux leakage from the casing 81 can be suppressed, and a sufficient magnetic attraction force can be secured to move the armature 84 closer to the electromagnetic coil 83. In addition, since the casing body 89 and the auxiliary yoke 90 can be manufactured by press working, the cost of the de-excitation type brake 42 can be reduced.

[0116] In this example, the thickness dimension T of the cylindrical portion 97 is also specified. a The cross-sectional area S of the cylindrical portion 97 a and the cross-sectional area S of the inner circumferential side wall portion 93 i The sum of (S a +S i ) is the cross-sectional area S of the outer peripheral wall portion 94 o The settings are configured to be as described above. As a result, the magnetic flux that can pass through the interior of the outer peripheral wall portion 94 and the magnetic flux that can pass through the interior of the cylindrical portion 97 and the inner peripheral wall portion 93 can be made to be approximately the same, thereby effectively suppressing magnetic flux leakage from the casing 81.

[0117] Furthermore, in this example, the auxiliary yoke 90 is not only fitted into the coil housing portion 91 that constitutes the casing body 89, but the outward engaging piece 98 provided on the auxiliary yoke 90 is mechanically engaged with the cut-up piece 96 (claw portion 96b) provided on the bottom wall portion 95 that constitutes the coil housing portion 91. As a result, regardless of the elastic force acting on the auxiliary yoke 90 from the compression spring 87 in the other axial direction, it is possible to effectively prevent the auxiliary yoke 90 from coming out of the casing body 89 in the other axial direction.

[0118] Furthermore, since the circumferential side of the engagement recess 98a, which is provided on the other axial side of the outward engaging piece 98, is cut and raised so that it faces the claw portion 96b of the piece 96, relative rotation of the auxiliary yoke 90 with respect to the casing body 89 can also be prevented.

[0119] Furthermore, in this example, since the compression spring 87 is positioned radially inward of the auxiliary yoke 90, the axial dimensions of the non-excitation-operated brake 42 can be reduced. In addition, since the auxiliary yoke 90 is provided with an inward engaging piece 99 that supports the elasticity of the compression spring 87, the casing 81 (auxiliary yoke 90) can be given the function of holding the compression spring 87. As a result, a dedicated part for holding the compression spring is not required, and the number of parts can be reduced.

[0120] In this example, instead of using a non-excitation brake 42, a worm gear reduction mechanism 58 without a self-locking function is used. Therefore, compared to using a worm gear reduction mechanism with a self-locking function, frictional resistance (energy loss) can be reduced, and input / output characteristics can be improved.

[0121] Although embodiments of the present invention have been described above, the present invention is not limited thereto and can be modified as appropriate without departing from the technical spirit of the invention.

[0122] The non-excitation type brake of the present invention is not limited to floating-type disc brake systems, but can also be applied to opposed-piston type disc brake systems. Furthermore, the non-excitation type brake of the present invention is not limited to disc brake systems, but can also be applied to drum brake systems. Moreover, the non-excitation type brake of the present invention is not limited to automobile brake systems, but can also be applied to brake systems for various machine tools and various industrial machinery.

[0123] The present invention is not limited to the structure described in the embodiments. For example, when implementing the present invention, the stationary disc can be omitted from the non-excitation brake, and only the rotating disc can be placed between the armature and the fixed plate. Also, the coil housing portion that constitutes the casing body is provided Cut and bent pieces The shape of the main body and the shape of the outer engaging portion provided on the auxiliary yoke can also be modified as appropriate. Furthermore, the shape of the inward engaging piece provided on the auxiliary yoke can also be modified as appropriate. [Explanation of symbols]

[0124] 1. Disc brake system 2 Support 3 Caliper 4a Outer pad 4b Inner Pad 5a First piston 5b Second piston 6a First rotational-to-linear motion conversion mechanism 6b Second rotary-to-linear motion conversion mechanism 7 Motor Gear Unit 8 rotors 9. Support base 10 Outer connection 11a, 11b connecting arm 12 mounting holes 13 Lining 14 Backing 15 Pressing part 16. Clamp base 17 Bridge section 18 Base Body 19a, 19b Arms 20a First Cylinder 20b Second cylinder 21a, 21b bottom 23a, 23b Female splines 24a, 24b Piston seals 25a, 25b sealing groove 26a, 26b Piston Boots 27a, 27b Guide pins 28a, 28b boots 29a, 29b spindles 30a, 30b nuts 31a, 31b Ball 32a, 32b Ball screw grooves on the shaft side 33a, 33b through hole 34a, 34b Support rings 35a, 35b thrust bearings 36a, 36b Ball screw groove on the nut side 37a, 37b Male spline 38a and 38b Circulation parts 39 Housing 40 Electric motors 41 Reduction mechanism 42 Non-excitation type brake 43a, 43b Mounting flange section 44a, 44b, 44c Mounting bolts 45 Housing body 46. ​​Cover plate section 47 Lid 48 Motor housing 49 Gear housing 50 Brake housing 51 Side wall section 52a, 52b Through holes 53 Motor body 54 Motor shaft 55 Motor Housing 56 First connection section 57 Second connection section 58 Worm gear reduction mechanism 59 Power distribution mechanism 60a~60e Gear 61 Warm 62 Worm Wheel 63 Warm teeth 64 Wheel Teeth 65 First Intermediate Axis 66 Second Intermediate Axis 67 Support shaft 68. First output shaft 69 Second output shaft 70a, 70b engaging hole 71 Gear train 73 Input Carrier 73a Teeth 74 First Intermediate Gear 75 Second Intermediate Gear 76 First output component 76a Input tooth section 76b Output teeth 77 Second output component 77a Input tooth section 77b Output teeth 78a, 78b Support ring 79a, 79b pins 80 connecting shafts 80a Male spline section 81 Casing 82 Fixing plate 82a Through hole 82b Mounting hole 83 Electromagnetic coil 84 Armature 85 RPM disc 85a Splined hole 86 Static disk 86a through hole 86b Engagement protrusion 87 Compression spring 89 Casing body 90 Auxiliary yoke 91 Coil housing section 92 Mounting flange section 92a Through hole 93 Inner circumferential side wall portion 94 Outer perimeter side wall 95 Bottom wall section 96 Cut and lifted pieces 96a Elevated section 96b Claw part 97 Cylindrical part 98 Outward engaging piece 99 Inward engaging piece 99a Axial plate part 99b Radial plate 100 rivets 101 Spacer 102 Electric wire 103 Bobbin

Claims

1. A non-excitation-operated brake for a braking device that allows rotation of the motor shaft when energized and prevents rotation of the motor shaft when de-energized, A casing having a coil housing section that functions as a yoke and has a substantially U-shaped cross-section and is configured as an annular shape overall, A fixing plate is fixed to the casing at a distance from the motor shaft in the axial direction, The electromagnetic coil housed in the coil housing section, An armature and an electromagnetic coil are positioned between the aforementioned fixing plate and the aforementioned electromagnetic coil. Between the fixed plate and the armature, a rotating disk is positioned coaxially with the motor shaft, The armature is biased in a direction away from the electromagnetic coil with respect to the axial direction of the motor shaft by a compression spring, The rotating disk is engaged with the motor shaft or a shaft that rotates synchronously with the motor shaft in such a way that it allows relative displacement of the motor shaft in the axial direction and prevents relative displacement of the motor shaft in the circumferential direction. The casing includes a casing body having the coil housing portion, and an auxiliary yoke that is substantially cylindrical in shape and fitted inside the coil housing portion, and is separate from the coil housing portion. The coil housing portion has an inner circumferential side wall portion arranged radially inside the electromagnetic coil, an outer circumferential side wall portion arranged radially outside the electromagnetic coil, and a bottom wall portion connecting the end of the inner circumferential side wall portion and the end of the outer circumferential side wall portion in the radial direction of the motor shaft. The inner circumferential side wall portion, the outer circumferential side wall portion, and the bottom wall portion each have the same thickness dimension. The bottom wall portion has a roughly L-shaped cut-out piece. The auxiliary yoke has an outward-facing engaging piece extending radially outward at the end of the motor shaft that is located opposite to the armature in the axial direction of the motor shaft, The auxiliary yoke is prevented from coming off the casing body by the engagement of the cut-up piece and the outward-facing engaging piece. Non-excitation type brake for braking systems.

2. The compression spring is a coil spring and is arranged radially inward of the auxiliary yoke, as described in claim 1, for a non-excitation-operated brake for a brake device.

3. The auxiliary yoke has an inward-facing engaging piece extending radially inward at the end located opposite the armature with respect to the axial direction of the motor shaft, The compression spring is positioned between the armature and the inward engaging piece with respect to the axial direction of the motor shaft. A non-excitation-operated brake for a brake device as described in claim 2.

4. The casing further comprises a stationary disk supported in such a way that relative displacement of the motor shaft in the axial direction is possible, but relative displacement of the motor shaft in the circumferential direction is impossible. The aforementioned rotating disks are provided in multiple quantities. The stationary disk is positioned between adjacent rotating disks with respect to the axial direction of the motor shaft. A non-excitation-operated brake for a brake device as described in any one of claims 1 to 3.

5. A caliper having a cylinder positioned inward from the rotor in the axial direction of the rotor, A piston fitted into the cylinder, A rotation-to-linear motion conversion mechanism is disposed within the cylinder and converts rotational motion into linear motion, thereby pushing the piston toward the rotor. The motor gear unit is supported and fixed to the caliper and drives the rotary-to-linear motion conversion mechanism, The motor gear unit includes an electric motor having a motor shaft, and a non-excitation-operated brake that allows the motor shaft to rotate when energized and prevents the motor shaft from rotating when de-energized. The aforementioned non-excitation-operated brake is a non-excitation-operated brake for a brake device as described in any one of claims 1 to 4. Disc brake system.

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