JP2003074605A - Motor for electric brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor for an electric brake having a rotation-straight line conversion mechanism capable of preventing axial enlargement irrelevant to the size of a stroke. SOLUTION: A cylindrical insertion hole 27 is provided inside an output shaft 7 in its axial direction. Two lock grooves 27a are provided in opposed positions on a straight line passing through the center of the insertion hole 27 positions from the internal circumferential surface of the insertion hole 27 towards its diametrical outside. The external shape of a lock bar 26 is formed of a diameter slidable to the internal circumferential face of the insertion hole 27, and a lock projection 26a as a detent mechanism having a dimension slidable to the internal circumferential surface of the lock groove 27a is attached to its outer edge part projecting diametrical outward of the lock bar 26. One of the two lock grooves 27a provided in the insertion hole 27 is slide-contacted with the lock projection part 26a provided in the lock bar 26 and the other becomes a ventilation groove 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle electric brake device.

[0002]

2. Description of the Related Art Conventionally, a vehicle disc brake device has been proposed which operates by an actuator having an electric motor as a drive source. Such an electric brake device is disclosed in, for example, Japanese Patent Publication No. 10-504876.

[0003]

However, when the rotation of the male screw is stopped by catching the disc pad, there is a high risk that the catch will come off due to pad wear and the amount of motor reversal, and when reassembling after maintenance. However, there was a problem that alignment was required. Further, since the mechanism for suppressing the rotation of the output shaft in the circumferential direction and enabling the reciprocating motion in the axial direction is configured outside the output shaft, the axial direction for enabling the reciprocating motion in the axial direction. Stroke was required, and the electric brake device was large.

The present invention has been made to solve the above problems, and an object thereof is to provide a rotation-linear conversion mechanism capable of preventing expansion in the axial direction regardless of the size of the stroke. To provide a motor for the electric brake.

[0005]

In order to solve the above problems, the invention according to claim 1 has a shaft portion and a shaft portion accommodating portion into which the shaft portion is screwed, In a motor for an electric brake equipped with a rotation-linear conversion mechanism that converts a rotational motion into a linear motion so that the shaft part moves straight by the rotation of the part housing part, the detent mechanism of the shaft part is formed inside the shaft part. Use as a summary.

According to a second aspect of the present invention, a locking rod is inserted inside the shaft portion, and at least one of the shaft portion and the locking rod is a space formed between the shaft portion and the locking rod. The gist is that a communication groove that communicates with the outside of the shaft portion is formed.

According to a third aspect of the present invention, the rotation preventing mechanism is provided by providing a locking projection and a locking groove on the shaft and the locking rod and engaging them with each other. Is
The gist is that at least one of the locking rod and the shaft portion is recessed at a position different from the rotation stopping mechanism.

(Operation) According to the invention described in claim 1,
Since there is no need to form a detent on the outside of the shaft accommodating part, there is no need for an axial stroke to enable axial reciprocation, preventing expansion of the shaft accommodating part in the axial direction. To be done.

According to the second aspect of the present invention, even if the locking rod is linearly moved in the shaft portion, the gas inside the space formed between the shaft portion and the locking rod is formed in the shaft portion. The pressure of
It is almost the same as the pressure around the shaft. Therefore, during the linear movement of the shaft portion, stress due to the difference between the pressure of the gas inside the space formed inside the shaft portion and the pressure of the gas around the shaft portion does not occur, and acts on the linear movement of the shaft portion. Does not reach.

According to the third aspect of the invention, since the communication groove is formed by forming a gap in a place different from the rotation stopping mechanism, the communication groove affects the engagement state of the rotation preventing mechanism. Without receiving it, a constant void is always formed.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an explanatory diagram of a vehicle electric disc brake device 1 of the present embodiment. The disc brake device 1 is a caliper floating type brake device. That is, the brake caliper 2 is a bracket (not shown) that rotatably supports an axle (not shown).
On the other hand, it is supported so as to be movable within a predetermined range in the axial direction of the axle. The brake caliper 2 has side surfaces (outer side surface, inner side surface) of the disk 3 fixed to the axle.
Brake pads 4 and 5 are arranged at positions facing each other. The outer brake pad 4 is fixed to the outer side of the brake caliper 2, and the inner brake pad 5 is supported on the inner side of the brake caliper 2 so as to be movable in a direction of contacting and separating from the disc 3.

The output shaft 7 as a shaft portion obtains a biasing force for pressing the inner brake pad 5 against the disc 3 by the operation of an actuator 8 as a rotation-linear conversion mechanism. Then, the tip portion 7a of the output shaft 7 presses the inner side brake pad 5 against the disk 3, and the reaction force generated at that time moves the brake caliper 2 to the inner side in the axial direction to cause the outer side brake pad 4 to move. Also presses against the disc 3.

Therefore, the brake pads 4 and 5 are the actuators 8 provided on the inner side of the brake caliper 2.
By the reciprocating (withdrawal) movement of the output shaft 7 housed inside the disk 3, the disk 3 is moved toward and away from the disk 3.

In this way, the brake pads 4, 5 are displaced relative to the disc 3 between the contact (pressure contact) state and the non-contact state, and a desired braking force is generated. The actuator 8 includes an electric motor 10 and an output section 12 provided in a rotary shaft 11 as a shaft section housing section of the motor 10.
In this embodiment, the motor 10 is a brushless motor that is electrically rectified to obtain a rotational force. The casing 13 of the motor 10 is fixed to the brake caliper 2. A cylindrical stator 14 is fixed inside the casing 13. The stator 14 is provided with an exciting coil 15 for applying a rotating magnetic field to a rotor 16 described later.

FIG. 2 is a sectional view taken along the line AA of FIG. As shown in FIG. 2, the stator 14 includes a stator core outer ring (hereinafter, simply referred to as an outer ring) 14 a, a stator core inner ring (hereinafter, simply referred to as an inner ring) 14 b, and an exciting coil 15. Teeth T <b> 1 to T <b> 9 are formed on the inner ring 14 b so as to extend radially so as to be connected to the outer ring 14 a and are evenly spaced. A winding is wound around each of the teeth T1 to T9 to form an exciting coil 15.

Inside the inner ring 14b of the stator 14, a cylindrical rotor 16 is provided. A magnetized magnet 17 is fixed to the outer peripheral surface of the rotor 16. Rotor 1
A cylindrical rotating shaft 11 is connected to the inside of 6 by a key 19 (see FIG. 1) so as to be integrally rotatable with respect to the rotor 16. The rotary shaft 11 has a base end supported by the casing 13 via a bearing 20, and a front end supported by the brake caliper 2 via a bearing 21.

An output unit 12 is formed in the rotary shaft 11. More specifically, the rotary shaft 11 is a nut member having a thread groove 11a on its inner peripheral surface. On the other hand, the output shaft 7
It is a screw shaft having a thread groove 7b on its outer peripheral surface. And, between the rotary shaft 11 and the output shaft 7, the mutual thread groove 1
It has a so-called ball screw structure in which a plurality of balls B assembled so as to be rollable along 1a and 7b are interposed. The output portion 12 is formed by the balls B and the thread grooves 11a and 7b formed on the rotary shaft 11 and the output shaft 7, respectively.

A flexible boot 22 is attached to an opening formed between the output shaft 7 and the brake caliper 2 to prevent water from entering the motor 10. The outer peripheral surface of the casing 13 is formed with a through hole 13a penetrating the front and back. The base end of the lead-out pipe 23 is fixed to the casing 13 so as to cover the through hole 13a. The proximal end of the flexible connection pipe 24 is attached to the distal end of the lead-out pipe 23. The connection pipe 24 extends to the floor panel of the vehicle. A power supply cable 25 for supplying drive power to the exciting coil 15 of the motor 10 from a brake controller (not shown) provided on the vehicle side is inserted into the pipes 23 and 24. Then, the brake controller controls the motor 10 according to the depression amount of the brake pedal to perform the above-described braking operation.

Next, a detailed description of the output shaft 7 will be given with reference to FIGS. 3 (a) and 3 (b). 3 (a) is an explanatory view showing the output shaft 7 in a simplified manner, and FIG. 3 (b) is shown in FIG.
It is sectional drawing by the CC line of (a).

As shown in FIGS. 3 (a) and 3 (b),
A cylindrical insertion hole 27 for inserting the locking rod 26 as a shaft portion is provided at the axial center of the output shaft 7 along the axial direction thereof.

From the inner peripheral surface of the insertion hole 27, two locking grooves 27a, 27b are provided at positions opposite to each other on a straight line passing through the center of the insertion hole 27 toward the radially outer side thereof as a detent mechanism. Has been. That is, the two locking grooves 27a and 27b
Are arranged so as to be located at both ends on the diameter of the insertion hole 27. The lengths of the locking grooves 27a and 27b in the axial direction of the output shaft 7 are formed to be the same as the insertion hole 27.

FIG. 4 is a cross-sectional view of the locking projection 26a as a locking mechanism for the locking rod 26. As shown in FIG. 4, the outer shape of the locking rod 26 is formed to have a slidable diameter on the inner peripheral surface of the insertion hole 27. On the outer edge portion of the locking rod 26, a locking projection 26 a as a rotation stopping mechanism having a size that allows sliding on the inner peripheral surfaces of the locking grooves 27 a and 27 b is provided.
6 is attached so as to project outward in the radial direction. The locking protrusion 26a is attached near the tip of the locking rod 26 (on the right side in FIG. 3A) so as to be fixed to the locking rod 26. The length of the output shaft 7 in the axial direction is such that the output shaft 7 can be prevented from rotating.

A fixed end 26b is formed at the base end portion (left side in FIG. 3A) of the locking rod 26 so as to be attached to and integrated with the casing 13. The fixed end 26b is integrated with the casing 13 so that the casing 13
It is fixed so that it cannot rotate.

The output shaft 7 and the locking rod 26 thus formed are slidable into the insertion hole 27 and the locking groove 27a provided inside the output shaft 7 with the locking rod 26 and the locking projection 26a. It is housed so that it can reciprocate in its axial direction while being in contact with it.

As shown in FIG. 3A, when the output shaft 7 reciprocates in the axial direction, the bottom surface of the insertion hole 27 formed inside the output shaft 7 and the locking fixed to the casing 13. Stick 2
A space 30 is formed between the front end of 6 (right side in FIG. 3A).

FIG. 5 is a sectional view taken along the line D-D passing through the locking projection 26a when the locking rod 26 shown in FIG. 3 (a) is inserted in the output shaft 7. As shown in FIG. 5, a locking rod 26 is slidably inserted into the inner peripheral surface of the output shaft 7. The locking protrusion 26a attached to the locking rod 26 is in sliding contact with one of the two locking grooves 27a and 27b (27a in this embodiment) provided in the insertion hole 27.

The other of the two locking grooves 27a and 27b (27b in this embodiment) communicates the space 30 with the outside of the output shaft 7 and serves as a ventilation groove 31 as a communication groove. The ventilation groove 31 is the locking groove 2 in which the locking protrusion 26a is not inserted.
7b, the ventilation groove 31 is similar to the locking groove 27b.
It is made equal to the axial length of the insertion hole 27, and the space 30 communicates with the outside of the output shaft 7 via a ventilation groove 31.

Next, the operation of the electric brake motor configured as described above will be described with reference to FIGS. 1 and 3 (a). When the brake pedal is depressed, the brake controller supplies the power supply cable 2 to the motor 10 according to the amount of depression.
A drive current is supplied via 5. When a drive current is applied to the motor 10, the rotary shaft 11 starts rotating.

When the rotary shaft 11 starts to rotate, the output shaft 7 inserted therein also tries to rotate in the same direction as the rotary shaft 11. Here, the locking rod 26 inserted into the output shaft 7 is integrally fixed to the casing 13 via the fixed end 26b, and is engaged with the locking protrusion 26a protruding from the locking rod 26. Since the stop groove 27a is engaged, the output shaft 7
Is held non-rotatable. Therefore, the output shaft 7 does not rotate together with the rotary shaft 11, but converts the rotary motion of the rotary shaft 11 into a linear motion in the axial direction by a ball screw structure formed around the rotary shaft 11. In this way, when the rotating shaft 11 of the motor 10 rotates in the forward and reverse directions, the output shaft 7 reciprocates in the axial direction accordingly.

When the output shaft 7 reciprocates in the axial direction, the bottom surface of the insertion hole 27 formed inside the output shaft 7 and the tip portion of the locking rod 26 fixed to the casing 13 (see FIG. 3A). The volume of the space 30 formed between (right side) increases and decreases.

Since the space 30 is connected to the outside of the output shaft 7 through the ventilation groove 31, even if the space 30 increases or decreases due to the reciprocating movement of the output shaft 7 in the axial direction, the space 30
The air pressure inside is kept equal to the air pressure outside the output shaft 7 through the ventilation groove 31.

As described above, this embodiment has the following effects. (1) In order to prevent the rotation of the output shaft 7, the fixed end 26b of the locking rod 26 is fixed to the casing 13. Therefore, the rotation of the output shaft 7 can be stopped by fixing only the fixed end 26b to the casing 13 regardless of the size of the stroke of the output shaft 7, thus preventing the motor from expanding in the axial direction and increasing the mounting flexibility. be able to.

(2) Even if the locking rod 26 reciprocates inside the output shaft 7 and the volume of the space 30 changes, the atmospheric pressure inside the space 30 is equal to the atmospheric pressure outside the output shaft 7. Therefore, stress due to the pressure difference between the atmospheric pressure in the space 30 and the outside of the output shaft 7 is not generated, and the operation loss of the output shaft 7 and the unintentional foreign matter from the outside when the atmospheric pressure in the space 30 becomes low ( Water etc.)
Can be prevented from entering.

(3) The insertion hole 27 is provided with two locking grooves 27a and 27b having the same shape so as to be aligned on the diameter of the insertion hole 27. The locking projection 26a is engaged with one of the locking grooves 27a to serve to restrict the rotation of the output shaft 7, and the other locking groove 27b serves as the ventilation groove 31 because nothing is inserted. To do. Therefore, the locking grooves 27a, 2
Since it is not necessary to separately form 7b and the ventilation groove 31, the output shaft 7 can be easily processed. Further, even when the locking rod 26 is inserted into the output shaft 7, it is not necessary to distinguish which locking groove 27a the locking protrusion 26a is inserted into, and the output shaft 7 and the locking rod 26 can be easily assembled. be able to.

(4) Since the ventilation groove 31 is formed by the locking groove 27b in which the locking projection 26a is not inserted, the ventilation groove 31 is always irrespective of the inserted state of the locking projection 26a.
Can be maintained in a constant state. Therefore, the space 30 is always connected to the outside of the output shaft 7 through the ventilation groove 31, and even if the space 30 increases or decreases due to the reciprocating movement of the output shaft 7 in the axial direction, the air pressure in the space 30 does not change. Through 31 it is possible to keep the pressure equal to the atmospheric pressure outside the output shaft 7.

(5) Space 3 formed inside the output shaft 7
Since the atmospheric pressure inside 0 is kept equal to the atmospheric pressure outside the output shaft 7, stress due to the atmospheric pressure difference between the atmospheric pressure inside the space 30 and the outside of the output shaft 7 does not occur, and the output shaft 7 smoothly moves. A round trip is performed. Therefore, the action of the reciprocating movement of the output shaft 7 on the brake pads 4 and 5 is promptly performed, and the braking performance can be improved.

The embodiment of the present invention may be modified as follows. In the above embodiment, the output shaft 7 having the cylindrical locking rod 26 and the corresponding cylindrical insertion hole 27 is used, but the locking rod is inserted into the output shaft to rotate the output shaft. It is sufficient that the structure has a ventilation groove that prevents the above and at the same time communicates the space 30 with the outside of the output shaft. Therefore, as shown in FIG. 6, the locking rod 40 is formed into a substantially square column shape, and the insertion hole 42 of the output shaft 41 is formed into a substantially square column shape corresponding to the size of the locking rod 40. The concave grooves 43, 44 directed toward the center may be provided at the side facing positions. With this configuration, the four corners of the locking rod 40 having a substantially quadrangular shape are inserted in the four corners of the insertion hole 42, which also have a substantially quadrangular shape, in a state of sliding contact with each other. The stop rod 40 does not rotate with respect to the output shaft 41. Therefore, it is not necessary to provide the engaging protrusion and the engaging groove for restricting the rotation of the output shaft 41 in the engaging rod 40 and the insertion hole 42, and the product can be easily manufactured.

In the above embodiment, the engaging grooves 27a and 27b are formed on the output shaft 7 at two places, and the engaging projection 26a is formed on the engaging rod 26. However, the engaging rod is inserted into the output shaft. It is sufficient that the structure has a ventilation groove that prevents the output shaft from rotating and at the same time connects the space 30 to the outside of the output shaft. Therefore,
As shown in FIG. 7, the output shaft 50 is formed with a locking projection 50a directed inward in the radial direction, and the locking rod 51 is provided with locking grooves 51a and 51b extending from the circumferentially opposed position toward the radial center at two positions. You may form. Even when the output shaft 50 and the locking rod 51 are formed in this way, the locking projection 50a is engaged with the one locking groove 51a to serve to restrict the rotation of the output shaft 50, and the other locking is performed. The groove 51b acts as a ventilation groove because nothing is engaged. Therefore, even when the locking rod 51 is inserted into the output shaft 50, the locking protrusion 50a is formed in which locking groove 51a,
It is not necessary to distinguish whether to engage with 51b, and the output shaft 50 and the locking rod 51 can be easily assembled.

In the embodiment shown in FIG. 6 described above, the ventilation groove is formed by providing the concave groove 43 in the center direction from the position facing both side surfaces of the locking rod 40, but from the space 30 to the outside of the output shaft 41. It suffices if there is a gas passage connected thereto. Therefore, a groove extending outward in the radial direction of the output shaft 41 from the insertion hole 42 provided in the output shaft 41 may be formed as a ventilation groove.

In the above embodiment, the example shown in FIG. 6 and the example shown in FIG. 7, two locking grooves are provided.
It suffices to have a ventilation groove that connects the space 30 and the outside of the output shaft when the locking rod is inserted, and three or more locking grooves may be provided.

In the above embodiment and the embodiment shown in FIG. 7, the positions where the locking grooves 27a and 27b are formed and the locking groove 5 are formed so that the locking rod can be easily assembled to the output shaft.
The locking groove was formed so that the formation positions of 1a and 51b were point-symmetrical. However, any structure may be adopted as long as the locking rod is inserted into the output shaft to prevent the output shaft from rotating and at the same time the ventilation groove for communicating the space 30 with the outside of the output shaft is provided. Therefore, the formation position of the locking groove does not have to be point-symmetrical, and for example, the angle formed by the two straight lines connecting the central axis of the locking rod and the locking groove may be a right angle.

In the above embodiment, the example shown in FIG. 6 and the example shown in FIG. 7, the locking projection and the locking groove were not mixed between the output shaft and the locking rod. However, any structure may be adopted as long as the locking rod is inserted into the output shaft to prevent the output shaft from rotating and at the same time the ventilation groove for communicating the space 30 with the outside of the output shaft is provided. Therefore, for example, both the locking projection and the locking groove may be formed on the output shaft.

The technical ideas that can be understood from the above embodiments will be described below. (A) In the electric brake motor according to claim 1 or 2, for inserting the locking rod (40) formed inside the locking rod (40) and the shaft portion (41). A motor for an electric brake, wherein each of the insertion holes (42) has a corresponding polygonal cross section. With this configuration, the rotation stopper for the shaft portion of the locking rod is prevented by the polygonal corner shape without using a locking member such as a key structure between the locking rod and the insertion hole into which the locking rod is inserted. It can be performed.

(B) In the electric brake motor according to the above (a), the locking rod (40) and the insertion hole (42) are substantially triangular or quadrangular in cross section. With this configuration, the insertion hole and the locking rod are less likely to slip in the circumferential direction of the shaft portion, and the rotation of the locking rod with respect to the shaft portion can be more reliably prevented.

(C) In the electric brake motor according to any one of claims 1 to 3, the rotation stopping mechanism (26a, 27a) is provided inside the shaft portion (7). An electric brake motor, characterized by being formed by engagement of a stop groove (27a) and a locking projection (26a) protruding from the locking rod (26).

(D) In the electric brake motor according to any one of claims 1 to 3, the detent mechanism (50a, 51a) is provided inside the shaft portion (50). An electric brake motor, characterized by being formed by engagement of a stop groove (50a) and a locking projection (51a) protruding from the locking rod (51).

[0047]

As described above in detail, according to the invention described in claims 1 to 3, there is provided the rotation-linear conversion mechanism capable of preventing the axial expansion regardless of the size of the stroke. An electric brake motor can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a disc brake device of the present embodiment.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an explanatory diagram of an output shaft.

FIG. 4 is a cross-sectional view of the locking rod at a locking projection position.

5 is a cross-sectional view taken along line DD of FIG.

FIG. 6 is a cross-sectional view of an output shaft and a locking rod of another example.

FIG. 7 is a sectional view of an output shaft and a locking rod of another example.

[Explanation of symbols]

7 ... Output shaft as shaft part, 8 ... Actuator as rotation-linear conversion mechanism, 11 ... Rotation shaft as shaft part accommodating part, 26 ... Locking bar as shaft part, 26a ... Locking as detent mechanism Convex portion, 27a ... locking groove as a detent mechanism, 27b ... locking groove as a void, 30 ... space,
31 ... Ventilation groove as a communication groove.

Continued front page    (72) Inventor Yuta Iwasaki             Asumo Corporation, 390 Umeda, Kosai City, Shizuoka Prefecture             In the company F term (reference) 3J058 AA48 AA53 AA63 AA78 AA87                       BA67 CC15 CC63 CC77 DC05                       DD09 FA01

Claims (3)

[Claims] 1. A shaft portion (7) and a shaft portion accommodating portion (11) into which the shaft portion (7) is screwed, and the shaft portion accommodating portion (11) is rotated to rotate the shaft portion accommodating portion (11). In a motor for an electric brake provided with a rotation-linear conversion mechanism (8) for converting a rotary motion into a linear motion so that the shaft part (7) moves straight, a detent mechanism (26a, 27) in the shaft part (7).
A motor for an electric brake, characterized in that a) is formed inside the shaft portion (7). 2. A locking rod (26) inside the shaft (7).
And a space (30) formed between the shaft portion (7) and the locking rod (26) in at least one of the shaft portion (7) and the locking rod (26). The electric brake motor according to claim 1, wherein a communication groove (31) is formed to communicate with the outside of the shaft portion (7). 3. The detent mechanism (26a, 27a)
Is performed by providing a locking projection (26a) and a locking groove (27a) on the shaft portion (7) and the locking rod (26) and engaging them with each other. (31) is the anti-rotation mechanism (26a, 2
The motor for an electric brake according to claim 2, wherein at least one of the locking rod (26) and the shaft portion (7) is recessed at a position different from 7a).