JP2022108380A - Valve timing control mechanism - Google Patents

Abstract

To provide a valve timing control mechanism which can be reduced in a size as a whole, and can suppress the intrusion of foreign matters.SOLUTION: A valve timing control mechanism comprises a valve-timing control motor having a conductor for constituting a motor coil, a circuit baseboard having a drive circuit for driving the motor, and a resin-made box body arranged between the motor and the circuit baseboard. A terminal being an end part of the conductor at a winding-end side is connected to the circuit baseboard through a terminal insertion hole which is formed at the box body, and an annular seal member is arranged at a periphery of the terminal insertion hole so as to surround the terminal insertion hole.SELECTED DRAWING: Figure 3

Description

The present invention relates to valve timing control mechanisms.

Automobiles are equipped with an electric valve timing control mechanism as a mechanism that can continuously change the opening and closing timing of the intake valve according to the engine speed and load. Modern valve timing control mechanisms are becoming more compact in order to improve engine mountability. In a conventional valve timing control mechanism, an ECU (Electronic Control Unit) and a resolver unit are connected via a harness.

The next-generation valve timing control mechanism has an electromechanical integrated structure for the purpose of miniaturization. An electromechanical integrated structure refers to a structure in which mechanical parts and electrical parts are integrated. For example, the technique described in Patent Document 1 is known as a conventional technique related to the electromechanical integrated structure. Japanese Patent Laid-Open No. 2002-200003 describes a technique related to "a control circuit-integrated brushless motor that can prevent foreign matter from entering a control circuit accommodating portion by a simple method". In the technique described in Patent Literature 1, the end frame of the motor body has a board housing recess that houses the circuit board of the control circuit and a communication hole that communicates with the inside of the motor body. are separated by reinforcing ribs functioning as separation walls, bearing accommodating portions, and terminal portions.

JP 2017-192214 A

However, in the technology described in Patent Document 1, it is necessary to connect the conductors protruding from the terminal portion of the motor and the circuit board of the control circuit via a relay terminal such as a bus bar, which increases the size of the entire mechanism. was inviting Further, when there is no separation wall between the substrate housing recess and the communication hole, the communication hole is wide open, so there is a drawback that foreign matter is likely to enter.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a valve timing control mechanism that can reduce the size of the mechanism as a whole and that can suppress the intrusion of foreign matter.

In order to solve the above problems, for example, the configurations described in the claims are adopted.
The present application includes a plurality of means for solving the above problems. One of them is a valve timing control motor having conductors forming a motor coil and a circuit board having a drive circuit for driving the motor. and a resin housing provided between the motor and the circuit board. The terminal, which is the winding end of the conductor wire, is connected to the circuit board through a terminal insertion hole formed in the housing, and an annular sealing member is arranged around the terminal insertion hole so as to surround the terminal insertion hole. It is

According to the present invention, it is possible to reduce the size of the mechanism as a whole and to prevent foreign matter from entering.
Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

1 is an exploded perspective view showing the overall configuration of a valve timing control mechanism according to an embodiment; FIG. FIG. 4 is a vertical cross-sectional view showing a state in which the motor, circuit board, and housing are fixed to each other in the valve timing control mechanism according to the embodiment; FIG. 3 is a longitudinal sectional view enlarging a B portion of FIG. 2 ; FIG. 4 is a longitudinal sectional view enlarging a part of FIG. 3;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this specification and the drawings, elements having substantially the same function or configuration are denoted by the same reference numerals, and overlapping descriptions are omitted.

FIG. 1 is an exploded perspective view showing the overall configuration of the valve timing control mechanism according to the embodiment.
In FIG. 1, a valve timing control mechanism 1 is a mechanism for controlling opening/closing timing of an intake valve provided in an automobile engine (not shown). A valve timing control mechanism 1 includes an electronic control device 2 and a motor 3 . In the embodiment, by stacking the electronic control device 2 on the motor 3, an integrated electromechanical structure is adopted in which the electronic control device 2 and the motor 3 are integrated.

The electronic control unit 2 controls driving of the motor 3 based on a control command given from an ECU (Electronic Control Unit) of the automobile or the like. The motor 3 functions as a drive source for the valve timing control mechanism 1 . A motor shaft 19 (see FIG. 2), which is an output shaft of the motor 3, is connected to the reduction gear 6. As shown in FIG. As a result, the speed reducer 6 rotates according to the direction and speed of rotation of the motor 3 . The speed reducer 6 is connected to a camshaft (not shown) having a cam for opening and closing an intake valve, and transmits the driving force of the motor 3 to the camshaft. Although FIG. 1 shows the speed reducer 6 as a separate element from the valve timing control mechanism 1, the valve timing control mechanism 1 may be configured to include the speed reducer 6. FIG.

The electronic control unit 2 includes a circuit board 4 having a drive circuit for driving the motor 3, a housing 5 that houses the circuit board 4, and a circuit board 4 housed in the housing 5 that is covered so as to be shielded from the outside. a cover 7; The circuit board 4 and the housing 5 are fixed together with the motor 3 described above by screws or the like. The housing 5 and the cover 7 are also fixed to each other by screws or the like.

The circuit board 4 is configured by a printed wiring board or the like. A plurality of electronic components constituting the drive circuit are mounted on the circuit board 4 . An opening 11 is formed in the circuit board 4 . The opening hole portion 11 penetrates the circuit board 4 in the board thickness direction. The opening hole portion 11 is formed in a circular shape in plan view in accordance with the shape of the bearing accommodating portion 13 of the housing 5 . The inner diameter of the bearing accommodating portion 13 is set larger than the outer diameter of the bearing 15 . Thereby, the bearing 15 can be accommodated in the bearing accommodating portion 13 . Moreover, the inner diameter of the opening hole portion 11 is set larger than the outer diameter of the bearing accommodating portion 13 . Accordingly, when the circuit board 4 is housed in the board housing portion 12 of the housing 5 , the bearing housing portion 13 of the housing 5 can be inserted into the opening hole portion 11 of the circuit board 4 . Further, the circuit board 4 is formed with a connector connecting portion 17 and a plurality of terminal receiving holes 25 . In the circuit board 4 , the openings 11 are formed between the connector connecting portion 17 and the plurality of terminal receiving holes 25 . The connector connection portion 17 is connected to the connector portion 14 of the housing 5 by a plurality of connector pins which will be described later.

The housing 5 is made of an electrically insulating resin. The housing 5 is formed with a substrate accommodating portion 12 that accommodates the circuit board 4, a bearing accommodating portion 13 that accommodates the bearing 15 of the motor 3, and a connector portion 14 for electrically connecting to the outside. . The board accommodating portion 12 is a concave space surrounded by the peripheral wall 16 of the housing 5 . The peripheral wall 16 is formed along the contour of the circuit board 4 . The bearing housing portion 13 is formed in a circular shape in plan view in accordance with the shape of the bearing 15 . The connector portion 14 is formed in a flat tubular shape so as to match the shape of a connector socket provided at the end of a wiring leading to an ECU of an automobile, for example, so that the connector socket can be pulled out. A plurality of connector pins (not shown) are arranged on the far side of the connector portion 14 in the direction in which the connector socket is inserted. The plurality of connector pins are pins for electrically connecting the connector socket inserted into the connector portion 14 and the connector connection portion 17 provided on the circuit board 4 . The plurality of connector pins are preferably integrally formed with housing 5 by insert molding.

FIG. 2 is a longitudinal sectional view showing a state in which the motor 3, the circuit board 4 and the housing 5 are fixed to each other in the valve timing control mechanism 1 according to the embodiment. Moreover, FIG. 3 is the longitudinal cross-sectional view which expanded the B section of FIG.
2 and 3, the motor 3, circuit board 4 and housing 5 are fixed together by screws 18. In FIG. As shown in FIG. 1, the circuit board 4 is formed with a screw insertion hole 23 through which the male screw portion of the screw 18 is inserted, and the housing 5 is also formed with a screw insertion hole 29b. Further, the flange portion 8 of the motor 3 is formed with a screw hole 9 that meshes with the male thread portion of the screw 18 . The male screw portion of the screw 18 is engaged with the screw hole 9 of the motor 3 through the screw insertion holes 23 and 29b.

The motor 3 has a motor shaft 19 which is an output shaft of the motor 3, a bearing 15 attached to the motor shaft 19 to rotatably support the motor shaft 19, and a conductor 22 constituting a motor coil. 22 constitutes a terminal 22a of the motor 3 as it is. Specifically, the end of the coiled wire 22 on the winding end side serves as a terminal 22 a of the motor 3 . The conducting wire 22 corresponds to a coil wire forming a motor coil.

Motor 3 is, for example, a three-phase motor. Bearing 15 is configured by, for example, a ball bearing. As shown in FIG. 2, two circumferential grooves 15a are formed on the outer peripheral surface of the bearing 15 so as to be offset in the axial direction of the motor shaft 19. As shown in FIG. An O-ring 41 is attached to the circumferential groove 15a. The O-ring 41 is arranged in close contact with the inner peripheral surface of the bearing accommodating portion 13 when the bearing 15 of the motor 3 is accommodated in the bearing accommodating portion 13 of the housing 5 . As a result, the clearance caused by the dimensional difference between the inner diameter of the bearing accommodating portion 13 and the outer diameter of the bearing 15 is maintained at a constant dimension over the entire circumference of the bearing 15 due to the presence of the O-ring 41 . Therefore, positional displacement of the bearing 15 can be suppressed. Further, the O-ring 41 functions as a cushioning material (cushion material) when the motor shaft 19 rotates or vibrates. Therefore, damage to the housing 5 due to contact with the bearing 15 can be suppressed. A lid member 26 is attached to the upper surface of the bearing accommodating portion 13 . Lid member 26 is made of, for example, an adhesive sheet. The cover member 26 closes the hole 13a formed in the bearing accommodating portion 13 so that dust and the like do not enter from the hole 13a.

A plurality of terminals 22 a are provided for one motor 3 . Each terminal 22a is bent like a crank and extends upward in FIG.

A plurality of terminal receiving holes 25 (see FIG. 3) are formed in the circuit board 4 . The terminal receiving holes 25 are through holes for soldering terminals 22 a of the motor 3 . On the other hand, the housing 5 is formed with a plurality of terminal insertion holes 27 (see FIG. 3). The terminal insertion hole 27 is a through hole through which the terminal 22a of the motor 3 is inserted. The terminal insertion hole 27 has a tapered shape in which the cross-sectional area gradually decreases from the motor 3 side to the circuit board 4 side. Specifically, as shown in FIG. 3, the terminal insertion hole 27 includes a first tapered portion 271 whose cross-sectional area gradually decreases from the motor 3 side to the circuit board 4 side, and a circuit opening from the motor 3 side. and a second tapered portion 272 whose cross-sectional area gradually increases toward the substrate 4 side. The inner diameter of the terminal insertion hole 27 is the minimum diameter at a boundary portion 273 between the first tapered portion 271 and the second tapered portion 272 . In the following description, the minimum diameter of terminal insertion hole 27 is referred to as the inner diameter of terminal insertion hole 27 . The inner diameter of the terminal insertion hole 27 is set larger than the outer diameter of the terminal 22a. Moreover, the inner diameter of the terminal insertion hole 27 is set smaller than the inner diameter of the terminal receiving hole 25 . The terminals 22 a of the motor 3 are electrically connected to the circuit board 4 by soldering portions 30 while being inserted into the terminal insertion holes 27 of the housing 5 and the terminal receiving holes 25 of the circuit board 4 .

Here, the dimensional difference (mm) between the inner diameter (minimum diameter) of the terminal insertion hole 27 and the outer diameter of the terminal 22a is ΔD1, and the dimensional difference (mm) between the inner diameter of the bearing accommodating portion 13 and the outer diameter of the bearing 15 is Assuming ΔD2, ΔD1 is smaller than ΔD2. Accordingly, the clearance caused by the dimensional difference between the inner diameter (minimum diameter) of the terminal insertion hole 27 and the outer diameter of the terminal 22a is smaller than the clearance caused by the dimensional difference between the inner diameter of the bearing accommodating portion 13 and the outer diameter of the bearing 15. Become.

A groove 45 is formed around the terminal insertion hole 27 in the housing 5 . The groove 45 is annular in plan view so as to surround the terminal insertion hole 27 . An O-ring 42 is attached to the groove 45 . The O-ring 42 is formed in an annular shape that is circular in plan view. The O-ring 42 is provided as an example of a sealing member. The O-ring 42 is compressed and deformed while being in close contact with the bottom surface of the groove 45 and the bottom surface of the circuit board 4 . The sealing member is not limited to the O-ring 42, and may be an annular elastic body surrounding the terminal insertion hole 27. FIG.

In the valve timing control mechanism 1 according to this embodiment, the terminals 22a of the motor 3 are directly connected to the circuit board 4 through the terminal insertion holes 27 of the housing 5 without passing through relay terminals such as bus bars. . As a result, there is no need to secure a space inside the valve timing control mechanism 1 for arranging a relay terminal or the like. Therefore, the size of the entire valve timing control mechanism 1 can be reduced. Further, in this embodiment, an O-ring 42 is arranged around the terminal insertion hole 27 . Therefore, the following effects can be obtained as compared with the case where the O-ring 42 is not arranged. First, when the O-ring 42 is not arranged, foreign matter 40 generated on the electronic control unit 2 side may enter the motor 3 side through the terminal insertion hole 27 of the housing 5 as indicated by the arrow in FIG. For example, if the foreign matter 40 entering the motor 3 gets caught in the O-ring 41 existing in the gap between the bearing housing portion 13 and the bearing 15, the O-ring 41 may be damaged. On the other hand, in the case where the O-ring 42 is arranged, when foreign matter 40 generated on the side of the electronic control unit 2 enters between the circuit board 4 and the housing 5 as shown in FIG. The O-ring 42 prevents the movement of the foreign object 40 toward the . Therefore, the O-ring 42 can prevent the foreign matter 40 generated on the electronic control unit 2 side from entering the motor 3 side through the terminal insertion hole 27 of the housing 5 .

Further, in this embodiment, the terminal insertion hole 27 has a tapered shape in which the cross-sectional area gradually decreases from the motor 3 side to the circuit board 4 side. Thereby, the terminal 22 a of the motor 3 can be guided by the terminal insertion hole 27 and led to the terminal receiving hole 25 .

Further, in the present embodiment, the O-ring 42 constitutes the sealing member that exhibits the effect of preventing foreign matter from entering as described above. Therefore, it is possible to suppress the intrusion of foreign matter 40 from the electronic control unit 2 side to the motor 3 side at low cost.

Further, in the present embodiment, the dimensional difference between the inner diameter of the terminal insertion hole 27 and the outer diameter of the terminal 22 a is smaller than the dimensional difference between the inner diameter of the bearing accommodating portion 13 and the outer diameter of the bearing 15 . Therefore, even if a foreign object 40a that may be caught in the gap between the bearing housing portion 13 and the bearing 15 exists inside the O-ring 42 as shown in FIG. You can prevent it from falling. As a result, it is possible to prevent the foreign matter 40 a from getting caught in the gap between the bearing housing portion 13 and the bearing 15 .

Incidentally, the foreign matter 40a generated inside the O-ring 42 may be a solder ball generated when the terminals 22a of the motor 3 are soldered to the terminal receiving holes 25 of the circuit board 4 by reflow. The size (diameter) of solder balls generated by reflow is about 0.15 mm. For this reason, the dimensional difference between the inner diameter of the terminal insertion hole 27 and the outer diameter of the terminal 22a is preferably less than 0.15 mm (excluding zero), and more preferably less than 0.12 mm (excluding zero). not included). By setting the dimensional difference between the inner diameter of the terminal insertion hole 27 and the outer diameter of the terminal 22a in this way, it is possible to prevent foreign matter 40a such as solder balls generated during reflow from entering the motor 3 side through the terminal insertion hole 27. can be effectively suppressed.

<Modifications, etc.>
In addition, the present invention is not limited to the above-described embodiments, and includes various modifications. For example, in the above-described embodiments, the details of the present invention have been described for easy understanding, but the present invention is not necessarily limited to having all the configurations described in the above-described embodiments. Also, part of the configuration of one embodiment can be replaced with the configuration of another embodiment. It is also possible to add the configuration of another embodiment to the configuration of one embodiment. Moreover, it is also possible to delete a part of the configuration of each embodiment, add another configuration, or replace it with another configuration.

REFERENCE SIGNS LIST 1 valve timing control mechanism 3 motor 4 circuit board 5 housing 13 bearing housing 15 bearing 22 wire 22 a terminal 27 terminal insertion hole 42 O-ring ( sealing material)

Claims (5)

a motor for valve timing control, which has conductors forming a motor coil;
a circuit board having a drive circuit for driving the motor;
a resin housing provided between the motor and the circuit board,
a terminal, which is an end of the winding end of the conductor wire, is connected to the circuit board through a terminal insertion hole formed in the housing;
A valve timing control mechanism in which an annular sealing member is arranged around the terminal insertion hole so as to surround the terminal insertion hole. 2. The valve timing control mechanism according to claim 1, wherein the terminal insertion hole has a tapered shape with a cross-sectional area gradually decreasing from the motor side to the circuit board side. 2. The valve timing control mechanism according to claim 1, wherein said sealing member is an O-ring. A bearing is attached to the motor shaft, which is the output shaft of the motor,
The housing is formed with a bearing accommodating portion that accommodates the bearing,
2. The valve timing control mechanism according to claim 1, wherein a dimensional difference between an inner diameter of said terminal insertion hole and an outer diameter of said terminal is smaller than a dimensional difference between an inner diameter of said bearing accommodating portion and an outer diameter of said bearing. 5. The valve timing control mechanism according to claim 4, wherein a dimensional difference between the inner diameter of the terminal insertion hole and the outer diameter of the terminal is less than 0.15 mm (excluding zero).

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