JPH09323643A - Hydraulic pump driving device for antilock brake control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic pump driving device in which decrease in the number of parts and mandays in assembly is realized and thereby a cost thereof is reduced. SOLUTION: Holes located on the inside of a motor positioning portion 2 provided in a housing 1 in which a hydraulic pump is contained is constructed from a motor positioning hole 2a opened in a motor mounting surface 1A of the housing, a shaft pass-through portion 2b opened in the housing 1 and a shaft bearing engage hole portion 2c. A front side spherical bearing 12 holding an end of a rotary shaft of a motor 3 is supported by a bearing engage hole portion 2c in an engaging manner and a positioning protrusion 9a located on a brush holding plate 9 is made to engage with a motor positioning hole portion 2a to position the motor. A rear end portion of a rotary shaft 6 of the motor is pressure fixed in an inner ring of a rear side spherical bearing 11 and an outer ring of the rear side spherical bearing 11 is fixedly pressed-in a shaft bearing support portion 4d provided at an end of a casing of the motor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic pump drive device for driving a hydraulic pump used in an antilock brake control device for an automobile.

[0002]

2. Description of the Related Art In order to prevent the wheels of an automobile from locking and slipping on the ground during braking, or losing the steering performance of the steering wheel, the braking torque is controlled so that the wheels do not lock during braking. An antilock brake control system (ABS) is used.

ABS controls the braking torque so as to keep the slip ratio of the wheel within an appropriate range, thereby always obtaining the maximum braking force and preventing a decrease in cornering force. Figure 3 is ABS1
00 schematically shows an example of the configuration of the main part of 00.

The ABS 100 shown in FIG. 3 is provided between a wheel speed sensor 101 for detecting a wheel speed, a controller 102 using a microcomputer, a brake master cylinder 103 and a wheel cylinder 104, and is provided by the controller. An actuator 105 that controls the hydraulic pressure applied from the master cylinder to the wheel cylinders in accordance with the applied command signal.

The controller 102 is required to obtain the slip ratio of the wheel from the rotational speed of the wheel detected by the wheel speed sensor and the vehicle speed estimated from the rotational speed of the wheel, and to keep the slip ratio within an appropriate range. Command is generated. This command is either a "pressure increase" command to increase the braking torque, a "hold" command to maintain the braking torque, or a "decrease" command to decrease the braking torque. Is.

The actuator 105 is provided with a reservoir tank 106 that receives brake fluid in the wheel cylinders in order to reduce the braking torque when a "pressure reduction" command is given, and a next time when a pressure increase command is given. Accumulator 107 for accumulating oil pressure, an oil pump 108 for supplying oil in the reservoir tank to the accumulator when a control operation for reducing the braking torque is being performed, and a command signal (current signal) generated by the controller 102. Solenoid valve 109 for appropriately switching the hydraulic circuit that connects among master cylinder 103, wheel cylinder 104, reservoir tank 106, hydraulic pump 108, and accumulator 107 in order to increase or decrease the braking torque according to And check valves 110-114 Constituted by a motor 3 for driving the hydraulic pump 108.

The solenoid valve 109 is the exciting coil 1
09a, a port p1 connected to a circuit reaching the master cylinder 103, a port p2 connected to a circuit reaching the wheel cylinder 104, and a port p3 connected to a circuit reaching the reservoir tank 106.
And the exciting coil 10 fitted in the cylinder 109b.
A plunger 109c that is driven to the right in the drawing when 9a is excited, and a valve body 109d that is provided in the plunger 109c to open and close the ports p1 and p3, respectively.
And 109e, a spring 109f for urging the valve elements 109d and 109e in directions to separate from each other, and a return spring 109g for returning the valve element 109e to the original position.

When the exciting coil 109a is not excited, the plunger 109c is at the position shown, the valve body 109e closes the port p3, and the valve body 109d opens the port p1. When a first magnitude of exciting current is applied to the exciting coil 109a, the plunger 109c is driven rightward in the drawing to move to the intermediate position of the cylinder 109b, and the valve element 109d closes the port p1. . At this time, the valve body 109e is still kept in the state in which the port p3 is closed. When the exciting coil 109 is supplied with an exciting current of a second magnitude larger than the first magnitude, the plunger 109c is driven further to the right, so that the valve body 109e opens the port p3. At this time, the valve body 109d is held in a state where the port p1 is closed. When the exciting current of the exciting coil 109a is set to zero, the plunger 109c returns to its original position and returns to the illustrated state.

In the state where the controller 102 is generating the pressure increase command, the exciting coil 1 of the solenoid valve 109 is
The excitation current of 09 is kept at zero. At this time, the solenoid valve 109 is in the illustrated state, and the master cylinder 1
03 is communicated with the wheel cylinder 104, and the communication between the wheel cylinder 104 and the reservoir tank 106 is cut off. Therefore, when the brake pedal 115 is depressed, the check valve 1 is released from the master cylinder 103.
Brake fluid flows to the wheel cylinder 104 through the solenoid valve 14 and the solenoid valve 109, and the wheel cylinder 10
The hydraulic pressure applied to 4 increases, and the braking torque increases.

While the controller 102 is issuing the hold command, the exciting current of the first magnitude is applied to the exciting coil of the solenoid valve 109. Therefore, the plunger 109c moves to the intermediate position, and the valve elements 109d and 109e close the ports p1 and p3, respectively. In this state, the communication between the master cylinder 103 and the wheel cylinder 104 is cut off, and the communication between the wheel cylinder 104 and the reservoir tank 106 is cut off, so that the hydraulic pressure of the wheel cylinder 104 is maintained and the braking torque is reduced. Retained.

When the controller 102 issues a pressure reduction command, the solenoid valve cuts off the communication between the master cylinder and the wheel cylinder, and connects the wheel cylinder and the reservoir tank. Therefore, oil flows from the wheel cylinder to the reservoir tank. The hydraulic pressure applied to the wheel cylinders decreases, and the braking torque decreases. At this time, the hydraulic pump 108 driven by the motor 3 supplies the brake fluid from the reservoir tank side to the accumulator side, and the pressure is accumulated in the accumulator. Since the accumulator is provided so as to communicate with the wheel cylinder when the boosting command is given, when the boosting command is given next, the pressure accumulated in the accumulator is given from the master cylinder. The braking torque is increased by being applied to the wheel cylinder together with the applied pressure.

[0012] For a detailed explanation of ABS, see, for example, the magazine "Automotive Engineering 1" published in November 1990.
January issue ”.

FIG. 2 shows a structure of a motor portion of a hydraulic pump used in a conventional ABS. In the figure, 1 is the housing of the ABS actuator,
The housing 1 accommodates the components of the actuator 105 shown in FIG. 3, such as the hydraulic pump 108 and the solenoid valve 109. The housing 1 has a motor mounting surface 1A on one surface thereof, and a motor positioning portion 2'is provided on a part of a wall portion of the housing on which the motor mounting surface 1A is provided.
Are formed. The illustrated motor positioning portion 2'is formed by punching a part of the wall portion of the housing inward. Inside the motor positioning portion 2 ', a motor positioning hole portion 2a' for positioning the motor and a rotation shaft of the motor are provided. And a shaft through hole portion 2b 'for penetrating therethrough are formed. The motor 3 for driving the hydraulic pump 108 is mounted on the motor mounting surface 1A of the housing.

The motor 3 shown in FIG. 2 is rotatably supported by a casing 4 fixed to the housing 1, a magnet field 5 mounted inside the casing 1, and the housing 1 and the casing 4. And a rotor 7 attached to the rotating shaft 6.

The casing 4 has a peripheral wall 4a, an end wall 4b closing one end of the peripheral wall in the axial direction, and an outer flange 4c provided at the other end of the peripheral wall 4a.
A magnet field 5 composed of an annular magnet is fixed to the inner circumference of the. The front cover 8 is in contact with the outer flange 4c of the casing 4, and the opening at the other end of the casing 4 is closed by the front cover 8. The brush holding plate 9 is fitted and fixed to the inner circumference of the end portion of the peripheral wall portion 4a of the casing 4 on the outer flange 4c side, and the pair of brushes 10, 10 are held on the brush holding plate 9.

Cup-shaped bearing holding portions 4d and 8a are formed in the central portion of the end wall 4b of the casing 4 and in the central portion of the front cover 8, respectively.
An outer ring of the rear side ball bearing 11 and an outer ring of the front side ball bearing 12 are slidably fitted to the inner circumferences of d and 8a. The rotating shaft 6 inserted into the casing 4 through the hole provided at the center of the brush holding plate 9 is press-fitted into the inner races of the ball bearings 11 and 12, and these bearings 11 and 12 allow the rotating shaft 6 to rotate. The shaft 6 is rotatably supported. In order to prevent the rotating shaft 6 from moving in the axial direction (thrust direction), a wave washer 13 is inserted between the rear side ball bearing 11 and the bottom wall portion of the bearing holding portion 4d, and the wave washer causes the bearing 11 to move. Is urged toward the front cover 8.

A rotor core 14 attached to the rotary shaft 6
The armature coil 15 is wound around the slot, and the rotor core 14 and the armature coil 15 constitute the rotor 7. Both ends of the armature coil 15 are connected to a commutator 16 mounted near the tip of the rotary shaft 6, and the commutator 16
The brushes 10, 10 are brought into contact with each other.

In the motor 3, the bearing holding portion 8a of the front cover 8 is fitted into the motor positioning hole 2a 'inside the motor positioning portion 2'of the housing, and the outer end surface of the front cover 8 is attached to the motor mounting surface 1A. The outer flange 4c of the casing 4 and the front cover 8 are bolted to the housing 1 so that the motor 3 is fixed to the housing 1. The tip of the rotary shaft 6 of the motor 3 is introduced into the housing 1 by loosely penetrating the shaft through hole 2b ′ provided in the motor positioning portion 2 ′.

An eccentric shaft portion 6a which is eccentric with respect to the central axis of the rotary shaft 6 is provided at the tip of the rotary shaft 6 introduced into the housing 1, and the eccentric shaft portion 6a is provided at one end of a link 18. It is fitted to the attached needle bearing 19. The other end of the link 18 is connected to an input portion for driving force of a hydraulic pump (not shown), and the eccentric shaft portion 6a, the needle bearing 19, and the link 18 constitute a connecting mechanism for connecting the rotary shaft of the motor 3 to the hydraulic pump. There is.

When the rotary shaft 6 of the motor 3 rotates, the needle bearing 19 rotates around the central axis of the rotary shaft 6 to reciprocate the link 18 in a direction perpendicular to the plane of the drawing. A hydraulic pump (not shown) is driven by the reciprocating motion of this link.

[0021]

The prior art A shown in FIG.
In the actuator for BS, the motor 3 for driving the hydraulic pump needs to have the front cover 8 for holding the front side ball bearing, and the wave washer 13 is provided for preventing the movement of the rotary shaft 6 in the axial direction. Needed. Therefore, there is a problem that not only the total length of the motor in the axial direction becomes long and its weight becomes large, but also the number of parts and the number of assembling steps increase and the manufacturing cost becomes high.

An object of the present invention is to construct a motor for driving a hydraulic pump used for an ABS without using a front cover or a wave washer, to reduce the size and weight of the motor and to reduce the number of parts and the number of assembling steps. Then, it aims at providing the hydraulic pump drive device of the anti-lock brake control device which can achieve cost reduction.

[0023]

SUMMARY OF THE INVENTION According to the present invention, a motor is mounted on a motor mounting surface provided on a part of a housing accommodating a hydraulic pump used in an automobile anti-lock brake control device, and the hydraulic pump is driven by the motor. The present invention relates to a hydraulic pump drive device. The motor used in the device targeted by the present invention has a peripheral wall portion, an end wall closing one end side in the axial direction of the peripheral wall portion, and an outer flange provided at the other axial end of the peripheral wall portion. A casing fixed to a motor mounting surface provided in a part of the housing, a magnet field fixed to an inner circumference of the casing, and arranged on the other end side in the axial direction of the casing. A brush holding plate whose outer peripheral portion is fitted and fixed to the inner peripheral surface of the peripheral wall portion of the casing, a rotary shaft which is inserted into the casing through a hole provided in the center portion of the brush holding plate, and a casing of the casing. A rear-side sphere that rotatably supports a rear end portion that is held in a cup-shaped bearing holding portion that is provided in the center of the end wall and that is open in the rotor yoke and that is located in the casing of the rotating shaft. Inside the bearing and magnet field A rotor formed by winding an armature coil around a rotor core arranged and attached to a rotating shaft, a front side ball bearing that supports the tip side of the rotating shaft, and attached to the rotating shaft and connected to the armature coil And a brush held by the brush holding plate and brought into contact with the commutator. The housing has a motor positioning portion on a wall portion provided with a motor mounting surface, and a tip end portion of a rotation shaft of the motor is introduced into the housing through a hole provided in the motor positioning portion. The tip of the rotary shaft introduced into the housing is connected to the input part of the hydraulic pump via a predetermined connecting mechanism.

In the present invention, the hole provided in the motor positioning portion of the housing has an inner diameter larger than the outer diameter of the front side ball bearing and is opened on the motor mounting surface, and the front side ball. The front side ball is located between the motor positioning hole and the shaft through hole, and the shaft through hole that has an inner diameter smaller than the outer diameter of the bearing and larger than the outer diameter of the tip of the rotary shaft and opens into the housing. The bearing fitting hole is formed to have a size such that the bearing can be fitted into and removed from the bearing.

Further, a positioning projection protruding toward the housing is provided on the inner circumference of the hole at the center of the brush holding plate, and the positioning projection is fitted into the inner circumference of the motor positioning hole. The outer flange of the casing is fixed to the housing while the brush holding plate is in contact with the motor mounting surface of the housing.

The outer ring of the front side ball bearing is fitted and held in the bearing fitting hole portion, and the outer ring of the front side ball bearing is fixed by press fitting into the bearing holding portion provided on the end wall of the motor casing. It The rear end of the rotating shaft is press-fitted and fixed to the inner ring of the rear side ball bearing.

With the above construction, the front side ball bearing of the motor is fitted and held in the bearing fitting hole portion of the housing, and the positioning projection provided on the brush holding plate is provided in the motor positioning hole of the housing. Since the motor is fixed to the housing in a state of being fitted and positioned on the inner circumference of the portion, it is not necessary to provide the front cover for holding the front side ball bearing and positioning the motor.

Further, as described above, when the rear end portion of the rotary shaft of the motor is press-fitted and fixed to the inner ring of the rear side ball bearing, and the outer ring of the rear side ball bearing is press-fitted and fixed into the bearing holding portion of the end wall of the casing, The wave washer for preventing the rotation shaft of the motor from moving in the axial direction can be omitted.

As described above, according to the present invention, since the front cover is not required and the wave washer is not required, the size of the motor in the axial direction can be made shorter than that of the conventional one, and the size of the motor can be reduced. Moreover, since the number of parts can be reduced, the weight of the motor can be reduced. Further, since the number of parts is reduced, the number of assembling steps is also reduced, so that the manufacturing cost can be reduced.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of the configuration of a hydraulic pump drive device according to the present invention.
The same reference numerals are given to the same parts as the respective parts.

In FIG. 1, reference numeral 1 denotes an ABS actuator housing, and the actuator components including a hydraulic pump are housed in the housing. The housing 1 has a motor mounting surface 1A on one surface thereof, and a part of a wall portion of the housing on which the motor mounting surface 1A is provided is driven inward to form a motor positioning portion 2. The motor 3 for driving the hydraulic pump 108 is mounted on the motor mounting surface 1A of the housing.

The motor 3 has a cylindrical peripheral wall portion 4a, an end wall 4b that closes one end of the peripheral wall portion in the axial direction, and a peripheral wall portion 4a.
Has a casing 4 integrally formed with a steel plate and an outer flange 4c provided at the other end of the casing. A magnet field 5 made of a permanent magnet such as a ferrite magnet is fixed to the inner periphery of the peripheral wall portion 4a of the casing. ing. End wall 4b of casing 4
A cup-shaped bearing holding portion 4d is provided in the center of the housing while opening in the casing 4, and a window 4e is formed in the center of the bearing holding portion. In the window 4e,
After the motor is assembled, the dustproof plug 20 made of rubber is attached.

Reference numeral 9 denotes a brush holding plate disposed on the other end side of the casing 4 in the axial direction, and the outer peripheral portion of the brush holding plate is press-fitted and fixed to the peripheral wall portion 4a of the casing 4. On the brush holding plate 9, a pair of brushes 10 and 10 arranged to face each other are held in a state of being elastically pressed by the brush pressing springs 21 and 21, respectively. In the inner peripheral portion of the hole at the center of the brush holding plate 9,
A positioning projection 9a is formed so as to project to the housing 1 side.

Reference numeral 6 denotes a rotary shaft that is inserted into the casing 4 by loosely penetrating a hole at the center of the brush holding plate 9. One end (rear end) of the rotary shaft 6 in the axial direction is a rear ball bearing. It is pressed into the inner ring of 11. The outer ring of the rear side ball bearing 11 is press-fitted and fixed to the inner periphery of a bearing holding portion 4d provided at the center of the end wall of the casing 4, and the rear side ball bearing 11 allows one end side (rear end portion) of the rotating shaft 6 to be rotated. ) Is rotatably supported.

Inside the magnet field 5, a rotor 7 mounted on a rotary shaft 6 is arranged. The rotor 7 is composed of a rotor core 14 attached to the rotary shaft 6 and an armature coil 15 wound around a slot of the rotor core, and is provided on the outer peripheral portion of the rotor core 14. The magnetic pole portion is opposed to the magnetic pole of the magnet field 5 via a predetermined gap. A commutator 16 is attached near the other end of the rotary shaft 6, and both ends of the armature coil 15 are connected to the commutator. The commutator 16 is in contact with the brushes 10, 10.

The other end portion (tip portion) of the rotary shaft 6 which protrudes to the outside of the casing 4 through the hole at the center of the brush holding plate 9 is press-fitted into the inner ring of the front side ball bearing 12. The outer ring of the front side ball bearing 12 is fitted into the bearing fitting hole 2c of the motor positioning portion 2 in a state that it can be inserted and removed, and the tip of the rotary shaft 6 protruding from the bearing 12 penetrates the motor positioning portion 2 through the shaft. It is introduced into the housing 1 in a state of loosely penetrating the hole 2b.

An eccentric shaft 6a is formed at the tip of the rotary shaft 6 introduced into the housing 1, and the eccentric shaft 6a is attached to one end of a link 18 for a needle bearing 19a.
Is inserted inside. Since one end of the link 18 is positioned in the axial direction of the rotary shaft, the outer periphery of the non-eccentric portion of the tip end portion of the rotary shaft 6 near the bearing 12 and the eccentric shaft portion 6b.
Collars 22 and 23 are press-fitted to the outer peripheries of the tip ends of the collars.

The hole formed inside the motor positioning portion formed on the housing 1 has a motor positioning hole portion 2a having an inner diameter larger than the outer diameter of the front side ball bearing 12 and opening on the motor mounting surface 1A. , Front side ball bearing 12
Shaft through hole 2 having an inner diameter smaller than the outer diameter of the rotary shaft 6 and larger than the outer diameter of the tip of the rotary shaft 6 and opening into the housing.
b, and a bearing fitting hole portion 2c between the motor positioning hole portion 2a and the shaft through hole portion 2b, the bearing fitting hole portion 2c having a size that allows the front side ball bearing 12 to be fitted in a removable state. Has been formed.

In the motor 3, the outer ring of the front side ball bearing 12 is fitted in the inner periphery of the bearing fitting hole 2c of the housing 1 so that it can be inserted and removed, and the positioning projection 9a of the brush holding plate is inserted into the motor positioning hole. The brush holding plate 9 is fitted to the inner circumference of the portion 2a and the motor holding surface 1A
Is fixed to the housing 1 by bolting the outer flange 4c of the casing to the housing.

A link 18 connected to the eccentric shaft portion 6a at the tip of the rotary shaft 6 via a needle bearing 19 is connected to one end of an operating rod for driving the piston of a reciprocating piston type hydraulic pump (not shown). The hydraulic pump is driven by the reciprocating motion of the link 18 that occurs as the rotary shaft 6 rotates.

With the above arrangement, the rear ball bearing 1
1 outer ring is press-fitted and fixed in the bearing holding portion 4d on the rear side,
Since the inner ring of the bearing 11 is fixed to the rotary shaft 6 by pressure fitting, no wave washer is required to prevent the rotary shaft 6 from moving.

Further, as described above, the front ball bearing 12 is fitted and held in the bearing fitting hole 2c provided in the housing 1, and the convex portion 9a provided in the brush holding plate is provided in the motor positioning hole provided in the housing. When the motor is positioned by fitting it to the portion 2a, the conventionally required front cover can be omitted.

In the above example, since the hydraulic pump is a reciprocating piston type pump, the rotary shaft 6 of the motor is connected to the hydraulic pump via a needle bearing and a link. When a pump is used, the rotary shaft of the motor 3 is connected to the input shaft of the hydraulic pump directly or via a speed reduction mechanism.

[0044]

As described above, according to the present invention, the hole provided in the motor positioning portion of the housing is constituted by the motor positioning hole portion, the shaft through hole portion, and the bearing fitting portion, and the motor front side ball is formed. The bearing is directly fitted and held in the bearing fitting hole of the housing, and the positioning protrusion provided on the brush holding plate is fitted in the motor positioning hole to position the motor. The cover can be omitted. Further, since the outer ring and the inner ring of the rear side ball bearing are fixed by pressure fitting to the bearing holding portion and the rotary shaft of the casing, respectively, the conventionally required wave washer can be saved. As described above, according to the present invention, since the front cover of the motor and the wave washer are not required, the number of parts and the number of assembling steps can be reduced, and the manufacturing cost can be reduced. Further, since the front cover and the wave washer can be omitted, the axial dimension of the motor can be reduced, and the hydraulic pump drive device can be made compact and lightweight.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration example of a hydraulic pump drive device according to the present invention.

FIG. 2 is a sectional view showing a configuration of a conventional hydraulic pump drive device.

FIG. 3 is a configuration diagram schematically showing a configuration example of an antilock brake control device.

[Explanation of symbols]

 1 Housing 1A Motor Mounting Surface 2 Housing Motor Positioning Part 2a Motor Positioning Hole 2b Shaft Through Hole 2c Bearing Fitting Hole 3 Motor 4 Casing 4a Peripheral Wall 4b End Wall 4c Outer Flange 4d Bearing Holding 5 Magnet Field 6 Rotational Shaft 6a Eccentric Shaft 7 Rotor 9 Brush Holding Plate 9a Positioning Protrusions 10, 10 Brush 11 Rear Side Ball Bearing 12 Front Side Ball Bearing 14 Rotor Iron Core 15 Armature Coil 16 Commutator

Claims (1)

[Claims] 1. An automobile having a peripheral wall portion, an end wall closing one end side in the axial direction of the peripheral wall portion, and an outer flange provided at the other axial end of the peripheral wall portion, wherein the outer flange is an automobile. Casing fixed to a motor mounting surface provided in a part of a housing accommodating a hydraulic pump used in an antilock brake control device for a vehicle, a magnet field fixed to an inner circumference of the casing, and an axial direction of the casing. Inside the casing, the brush holding plate, which is arranged on the other end side of the casing and whose outer peripheral portion is fitted and fixed to the inner periphery of the peripheral wall portion of the casing, and the hole provided in the central portion of the brush holding plate, is loosely penetrated. And a rotary shaft inserted into the casing and held in a cup-shaped bearing holding portion provided in a central portion of an end wall of the casing and opened in the rotor yoke, and positioned inside the casing of the rotary shaft. A rear side ball bearing that rotatably supports a rear end portion, a rotor that is disposed inside the magnet field and that is attached to the rotation shaft, and has an armature coil wound around the rotor core; A front side ball bearing supporting the tip side of the shaft; a commutator attached to the rotating shaft and connected to the armature coil; and a brush held by the brush holding plate and brought into contact with the commutator. Of an anti-lock brake device including a motor having: a front end portion of a rotation shaft of the motor, which is introduced into the housing through a hole provided in a motor positioning portion provided in the housing and is connected to the hydraulic pump. In the hydraulic pump drive device, the hole of the motor positioning portion of the housing has an inner diameter larger than the outer diameter of the front side ball bearing and is opened in the motor mounting surface. A motor positioning hole portion, a shaft through hole portion having an inner diameter smaller than an outer diameter of the front side ball bearing and larger than an outer diameter of a tip portion of the rotating shaft, and opening into the housing; A bearing fitting hole formed between the hole and the shaft through hole, the bearing fitting hole having a size such that the front side ball bearing can be fitted in a removable state. A positioning protrusion protruding toward the housing is provided on the inner periphery of the hole at the center, and the positioning protrusion is fitted to the inner periphery of the motor positioning hole, and the brush holding plate is The outer flange of the casing is fixed to the housing while being in contact with the motor mounting surface of the housing, and the outer ring of the front side ball bearing is fitted in the bearing fitting hole. The outer ring of the rear side ball bearing is press-fitted and fixed in the bearing holding portion of the end wall of the casing, and the rear end of the rotary shaft is press-fitted and fixed to the inner ring of the rear side ball bearing. A characteristic feature of the anti-lock brake control system hydraulic pump drive.