Patent ID: 12206312

DETAILED DESCRIPTION

A description will hereinafter be made on a motor and a manufacturing method of the motor according to the present invention with reference to the drawings. A configuration, operation, and the like, which will be described below, constitute merely one example, and the motor and the manufacturing method thereof according to the present invention are not limited to a case with such a configuration, such operation, and the like.

In addition, in each of the drawings, detailed portions will appropriately be simplified or will not be illustrated. An overlapping description will appropriately be simplified or will not be made.

Description on Configuration of Vehicle Brake Control System

FIG.1illustrates a brake control system20, and only illustrates a brake system for one wheel in a hydraulic circuit of a brake system for four wheels. InFIG.1, the brake control system20is applied to the brake system that increases a brake pedal depression force by a driver without using a booster and transmits the increased depression force to a wheel cylinder. However, the booster may be used in an example of the brake system.

The brake control system20has four of first to fourth hydraulic circuits. Because each of the second to the fourth hydraulic circuits has the same configuration as the first hydraulic circuit, the second to the fourth hydraulic circuits are not illustrated inFIG.1. The wheel cylinders for four wheels are supplied with a brake fluid from a master cylinder13via the first to fourth hydraulic circuits, respectively.

A first hydraulic circuit30includes a pump45that is driven by a motor49. The first hydraulic circuit30also includes an accumulator25and a damper27.

The pump45is driven by the motor49and discharges the brake fluid. Driving of the motor49is controlled by a brake electronic control unit10.

A pipeline that communicates with the master cylinder13is provided with a first pressure sensor17. The first pressure sensor17detects an internal pressure of the master cylinder13.

A pipeline that communicates with a wheel cylinder14in a hydraulic brake15for the wheel is provided with a second pressure sensor16. The second pressure sensor16detects an internal pressure of the wheel cylinder14.

The first hydraulic circuit30includes a plurality of electromagnetic control valves. The electromagnetic control valves include: a circuit control valve22of a normally-open type that can be controlled linearly; a suction control valve26of a normally-closed type that is subjected to on/off control; a booster regulator23of the normally-open type that can be controlled linearly; and a pressure regulator24of the normally-closed type that is subjected to the on/off control.

The circuit control valve22is arranged in a channel32that connects the master cylinder13and a discharge side of the pump45. The circuit control valve22can be controlled linearly, and continuously regulates an area of a channel between the master cylinder13and the booster regulator23.

The suction control valve26is arranged in a channel31that connects the master cylinder13and a suction side of the pump45. The suction control valve26communicates between the master cylinder13and the suction side of the pump45, or blocks the communication between the master cylinder13and the suction side of the pump45.

The booster regulator23is arranged on a channel33that connects the circuit control valve22and the wheel cylinder14. The booster regulator23can be controlled linearly, and continuously regulates a flow rate of hydraulic oil from a side of the master cylinder13and the circuit control valve22to a side of the wheel cylinder14in the hydraulic brake15for the wheel.

The pressure regulator24is arranged in a channel34that connects the suction side of the pump45and the wheel cylinder14. The pressure regulator24communicates between the suction side of the pump45and the wheel cylinder14, or blocks the communication between the suction side of the pump45and the wheel cylinder14. In an open state, the pressure regulator24supplies the hydraulic oil that has been supplied to the wheel cylinder14in the hydraulic brake15for the wheel to the accumulator25, so as to lower a hydraulic pressure. By repeatedly opening/closing the pressure regulator24intermittently, the flow rate of the hydraulic oil from the wheel cylinder14to the accumulator25can be regulated.

The brake electronic control unit10receives a signal related to a physical amount from each of a brake pedal sensor (not illustrated) that measures an operation amount of a brake pedal11, a wheel rotational frequency sensor18, and the pressure sensors16,17. Then, on the basis of the signals, the brake electronic control unit10controls the electromagnetic control valves and the motor49for driving the pump45, supplies the hydraulic pressure to the wheel cylinder14, and thereby causes generation of a braking force that brakes a vehicle.

A description will be made on a state of each of the electromagnetic control valves and a flow of the hydraulic oil at the time when anti-lock brake control is executed. When the brake electronic control unit10initiates the anti-lock control for the wheels, the booster regulator23is closed, and the pressure regulator24is opened. As a result, the hydraulic oil that has been supplied to the wheel cylinder14flows into the accumulator25. According to a slip state of the wheel, the pressure regulator24is repeatedly and appropriately turned on/off so as to regulate the hydraulic pressure in the wheel cylinder14. The hydraulic oil that has flowed into the accumulator25drives the motor49, actuates the pump45, and then flows back to the master cylinder13via the open circuit control valve22and the channel32.

Next, a description will be made on the state of each of the electromagnetic control valves and the flow of the hydraulic oil at the time when brake traction control (automatic pressure boost control) is executed. When the brake electronic control unit10initiates the brake traction control for the wheels, the circuit control valve22is closed, the suction control valve26is opened, and the pump45is actuated by rotation of the motor49. In this way, the hydraulic oil in the master cylinder13is supplied to the wheel cylinder14via the channel31, the suction control valve26, the pump45, and the channel33.

The hydraulic pressure of the hydraulic oil to be supplied to the wheel cylinder14is appropriately regulated by opening/closing control of the booster regulator23and/or the pressure regulator24.

Description on Internal Structures of Motor and Piston Pump

A description will be made on internal structures of the motor49and the pump45with reference toFIG.2.

A structure for holding a second bearing67inFIG.2corresponds to the related art of the invention of the present application, and another configuration can also be applied to the invention of the present application. An output rotary shaft50is formed with an eccentric portion52in one end portion that is arranged in a cylinder bore of a hydraulic block51in which the hydraulic circuit is installed, and also functions as an input rotary shaft of the piston pumps45,48.

In one of the two cylinder bores, each of which is formed in the hydraulic block51to have an orthogonal axis to an axis of the eccentric portion52, a piston53of the piston pump45is arranged. In the other cylinder bore, a piston54of the piston pump48is arranged. The pistons53,54are urged toward the eccentric portion52by springs57,58arranged in pump chambers55,56, respectively. An inner end of each of the pistons53,54abuts an outer ring of a roller bearing59that is assembled to an outer periphery of the eccentric portion52.

The motor49has a case that is formed of: a motor housing61having an opening and accommodating a rotor60fixed to the output rotary shaft50; and a case member63to which a connection terminal62connected to a motor drive circuit, and the like are assembled. A magnet64is fixed to an inner wall61aof the motor housing61. The motor housing61and the case member63are joined to the hydraulic block51by bolts65in a state where the case member63is interposed between the motor housing61and the hydraulic block51. The one end portion of the output rotary shaft50is supported by a first bearing66while the other end portion thereof is supported by the second bearing67. InFIG.2, each of the first and second bearings66,67is configured as a ball bearing.

An inner ring68of the first bearing66press-fits the output rotary shaft50such that an inner periphery of the inner ring68is fixed to the output rotary shaft50. An outer periphery of an outer ring69of the first bearing66is supported by the hydraulic block51and the case member63.

Meanwhile, an outer ring71of the second bearing67is press-fitted and fixed into a cup-shaped portion75, and one end of the output rotary shaft50is fitted to an inner ring70of the second bearing67.

The cup-shaped portion75is formed in a bottom portion72of the motor housing61, and is formed by folding the bottom portion72of the motor housing61so as to be opened to an internal space of the motor housing61.

In the structure for holding the second bearing67according to the related art as illustrated inFIG.2, after the second bearing67is press-fitted and fixed into the inside of the cup-shaped portion75, the output rotary shaft50has to be fitted to the inner ring70of the second bearing67. At the time of this fitting, a press-fitting force that is applied to the inner ring70of the second bearing67is transmitted to the outer ring71via a rolling element of the second bearing67, which applies a large load on the rolling element and possibly causes damage to a spherical surface of the rolling element.

In order to reduce this load by the press-fitting force, in the related art, the output rotary shaft50is fitted to the second bearing67in a state of having a certain amount of a clearance between an inner wall of the inner ring70of the second bearing67and an outer periphery of the output rotary shaft50. Thus, the output rotary shaft50is not tightly fixed to the inner ring70of the second bearing67, which causes a rotational frequency difference between the output rotary shaft50and the inner ring70of the second bearing67.

Example 1

A description will be made on a first example of a motor that has a bearing holder according to the invention of the present application with reference toFIG.3. Of the configurations of the motor described with reference toFIG.2, the description on the same configuration will not be made.

The output rotary shaft50is supported by at least two points that are the first bearing66arranged on the side of the piston pump45and the second bearing67arranged on the side of the bottom portion72of the motor housing61.

The outer ring71of the second bearing67is held by a bearing holder80. The bearing holder80according to the first example is formed of a disc85in a substantially disc shape and a peripheral wall portion84that is provided perpendicularly from an outer peripheral portion of the disc85. The disc85is formed with: a hole portion82in a substantially circular shape in a central portion thereof; and slits83, each of which extends in a radial direction of the disc85from a circumference of the hole portion82. In the bearing holder80illustrated inFIG.3, six slits83are arranged at equally-spaced intervals.

The bearing holder80is press-fitted into and held in the bottom portion72of the motor housing61. More specifically, in a state where an extending direction of the peripheral wall portion84faces downward, the bearing holder80is inserted in the motor housing61. The peripheral wall portion84of the bearing holder80is formed such that a diameter86thereof is slightly larger than an inner diameter of the motor housing61. Thus, the outer periphery of the peripheral wall portion84of the bearing holder80is pressed against the inner wall61aof the motor housing61, and the bearing holder80is thereby held in the motor housing61.

In addition, the hole portion82of the disc85is formed to have a slightly smaller diameter than the second bearing67. Thus, when the second bearing67is pushed into the hole portion82of the bearing holder80, a blade portion81of the disc85is bent downward, and, with an elastic repulsive force of the blade portion81generated by such bending, a tip81aof the blade portion81presses an outer periphery of the second bearing67inward. As a result, the second bearing67is held in the bottom portion72of the motor housing61by the bearing holder80.

In the state where the second bearing67is held by the bearing holder80, as illustrated inFIG.3, the blade portion81of the bearing holder80has an inclined portion81bthat is inclined with respect to a surface of the bottom portion72of the motor housing61.

Example 2

A description will be made on a second example of the motor that has the bearing holder according to the invention of the present application with reference toFIG.4. Of the configurations of the motor described with reference toFIG.2andFIG.3, the description on the same configuration will not be made.

The second bearing67is arranged in the bottom portion72of the motor housing61, and the outer ring71of the second bearing67is held by a bearing holder90. The bearing holder90according to the second example is configured to include: a disc91that substantially has a donut shape and has a hole portion94at a center thereof; an outer peripheral wall portion92athat extends perpendicularly to a surface of the disc91from an outer peripheral portion92of the disc91; and an inner peripheral wall portion93athat extends perpendicularly to the surface of the disc91from an inner peripheral portion93of the disc91. In the inner peripheral wall portion93a, slits95are arranged at equally-spaced intervals along a circumference.

The bearing holder90is press-fitted into and held in the bottom portion72of the motor housing61. More specifically, in a state where extending directions of the outer peripheral wall portion92aand the inner peripheral wall portion93aface upward inFIG.4, the bearing holder90is inserted in the motor housing61. The outer peripheral wall portion92aof the bearing holder90is formed such that a diameter thereof is slightly larger than the inner diameter of the motor housing61. Thus, an outer periphery of the outer peripheral wall portion92aof the bearing holder90is pressed against the inner wall61aof the motor housing61, and the bearing holder90is thereby held in the motor housing61. In addition, similar to an inner peripheral portion72aof the bottom portion72of the motor housing61, an outer surface92bat a position where the outer peripheral wall portion92ais vertically provided may be chamfered. As a result, the bearing holder90can acquire a sufficient holding force from the inner peripheral portion and the bottom portion72of the motor housing61.

In addition, the hole portion94of the disc91is formed such that an inner diameter thereof is slightly smaller than the diameter of the second bearing67. Thus, when the second bearing67is pushed into the hole portion94of the bearing holder90, the inner peripheral wall portion93ais slightly bent to an outer side of the disc91, and, with a repulsive force that is generated by such bending and attempts to return the inner peripheral wall portion93ainward, the inner peripheral wall portion93apresses the outer periphery of the second bearing67inward. As a result, the second bearing67is held in the bottom portion72of the motor housing61by the bearing holder90.

Instead of the above, a mechanical that holds the second bearing67in the inner peripheral wall portion93awhile setting the inner diameter of the hole portion94of the disc91to be the same as the diameter of the second bearing67may be provided. More specifically, such a structure may be adopted that a small projected portion (not illustrated) crushed at the time when the bearing is inserted in the inner peripheral wall portion is provided and, after the bearing is inserted, the bearing is held by a pressing force of the projected portion.

In the second example, the effect of the invention can be exerted even when the hole portion94is not provided.

Manufacturing Method of Motor

S1: Attach the second bearing67to the output rotary shaft50.S2: Attach the rotor60to the output rotary shaft50.S3: Attach the case member63to the output rotary shaft50.S4: Attach the first bearing66to the output rotary shaft50.S5: Attach the roller bearing59to the eccentric portion52of the output rotary shaft50.S6: Attach the bearing holder80or90to the motor housing61.S7: Attach the magnet64to the motor housing61.S8: Attach an assembly1to an assembly2.

A description will hereinafter be made on a manufacturing method of the motor according to the invention of the present application with reference toFIG.5. The manufacturing method of the motor includes a step of processing each component, a step of winding a coil, and the like. However, a description will herein be made only on a step of assembling each of the components or each assembled component according to characteristics of the present invention. A known method can be adopted for other steps related to manufacturing of the motor.

In manufacturing step S1, attachment work of the second bearing67, which is arranged in the bottom portion72of the motor housing61, to the output rotary shaft50is performed. More specifically, the output rotary shaft50is press-fitted into the inner ring70of the second bearing67, so as to fix the second bearing67to the output rotary shaft50.

In manufacturing step S2, attachment work of the rotor60to the output rotary shaft50is performed. For example, a shrink-fit jig is used to fit the output rotary shaft50to a shaft hole provided in the rotor60in an inserted state of the output rotary shaft50in the shaft hole.

In manufacturing step S3, the case member63that includes a drive unit of the motor49is attached to the output rotary shaft50.

In manufacturing step S4, the first bearing66that is arranged on the side of the piston pumps45,48is attached to the output rotary shaft50. More specifically, the output rotary shaft50is press-fitted into the inner ring68of the first bearing66, so as to fix the first bearing66to the output rotary shaft50.

In manufacturing step S5, the roller bearing59is attached to the eccentric portion52of the output rotary shaft50. More specifically, the eccentric portion52is press-fitted into an inner ring of the roller bearing59, so as to fix the roller bearing59to the output rotary shaft50.

By executing manufacturing steps S1to S5, the assembly of the components attached to the output rotary shaft50is finished. A semi-finished product that is assembled in manufacturing steps S1to S5will be set as the assembly1.

After manufacturing step S5is terminated, or in parallel with manufacturing steps S1to S5, manufacturing step S6is executed. In manufacturing step S6, the bearing holder80or90is attached to the motor housing61. As it has already been described, each of the bearing holders80,90is press-fitted and fixed into the motor housing61so as to be held by the inner wall61aof the motor housing61.

In manufacturing step S7, the magnet64that functions as a stator of the motor49is attached to the motor housing61. The attachment of the magnet64may be achieved through fitting including plastic deformation or by adhesion of the magnet64to the inner wall61aof the motor housing61using an adhesive.

By manufacturing steps S6to S7, the assembly of the components attached to the motor housing61is finished. A semi-finished product that is assembled in manufacturing steps S6to S7will be set as the assembly2.

In manufacturing step S8, attachment work of the assembly1to the assembly2is performed. The second bearing67that is attached to the one end of the output rotary shaft50is fitted to the hole portion82or94of the bearing holder80or90, the second bearing67is press-fitted to a specified position on the side of the bottom portion72of the motor housing61, and the second bearing67is thereby press-fitted and fixed into the bearing holder80or90. At the same time, the case member63covers an opening of the motor housing61, and the case member63is joined to a flange in the opening of the motor housing61by a screw or the like.

In the motor and the manufacturing method thereof according to the invention of the present application, before the output rotary shaft50is attached to the motor housing61, the second bearing67can press-fit and be fixed to the output rotary shaft50in advance. Compared to the case where the output rotary shaft50and the second bearing67are fitted to each other while having the clearance therebetween, it is possible to suppress generation of creep noise. In addition, the special processing to form a cup-shaped portion in the bottom portion of the motor housing in order to hold the second bearing67as in the related art is unnecessary. Thus, it is possible to provide the motor structure capable of supporting the output rotary shaft50simply by press-fitting and fixing the bearing holder into the motor housing61.

REFERENCE SIGNS LIST

10: Brake electronic control unit45,48: Piston pump49: Motor52: Eccentric portion59: Roller bearing60: Rotor61: Motor housing63: Case member64: Magnet66: First bearing67: Second bearing80,90: Bearing holder