JP4929913B2 - Flow control valve - Google Patents

Description

  The present invention relates to a flow rate control valve that converts a rotational force applied from a stepping motor into an axial force and uses this axial force to manipulate the opening of a flow path.

Conventionally, for example, in order to control the amount of intake air when the engine is idling, a flow control valve as described above using a stepping motor as an actuator has been used.
This conventional flow control valve is provided with a valve body that converts a rotational force applied from a stepping motor into an axial force and is displaced in the axial direction in accordance with the axial force. (For example, refer to Patent Documents 1 and 2).

  Here, the rotational force applied from the stepping motor is converted into an axial force as follows. That is, a screw is provided on a rotor that is rotated by energizing the stepping motor, the screw of the rotor is screwed with a screw provided on the valve body, and the valve body is kept non-rotatable by a predetermined locking means. Accordingly, when the stepping motor is energized and the rotor is rotated, the rotational force applied to the valve body is converted into an axial force, and the valve body is displaced in the axial direction by this axial force.

  By the way, according to the conventional flow control valve, due to the presence of the degree of axial misalignment between the shaft center of the member (opening operation member) that forms the flow path to be operated and the shaft center of the valve body, Have problems with such valve leaks.

For example, as described in Patent Document 1, when the flow path opening and closing by the valve body is a spool valve system, it is necessary to widen the sliding gap according to the degree of shaft misalignment in order to prevent the valve body from being locked. Valve leakage is likely to occur due to the expansion of the sliding gap. In addition, as described in Patent Document 2, when the flow path opening and closing by the valve body is a poppet valve system, an inclination with respect to the seating position is generated according to the degree of shaft misalignment, and valve leakage is likely to occur due to this inclination.
JP 2006-37916 A JP-A-11-201004

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a flow control valve having a stepping motor as an actuator between an axis of an opening operation member and an axis of a valve body. The purpose is to improve the degree of shaft misalignment and reduce the risk of valve leakage.

[Means of Claim 1]
According to a first aspect of the present invention, the flow control valve converts the rotational force applied from the stepping motor into an axial force, and the shaft member is displaced in the axial direction according to the axial force. And a valve member that is displaced in the axial direction in response to the urging force applied from the urging means and the axial force transmitted from the shaft member, and displacing the shaft member in the axial direction, The valve member is displaced to manipulate the opening of the flow path.

  Thereby, the degree of freedom of an axis of a valve member improves rather than the conventional valve body. That is, the conventional valve body has two functions of a driving force conversion function that converts a rotational force into an axial force and an original valve function, and in order to realize the driving force conversion function, It has a threaded structure between them. The axial center of the valve body is strongly bound by this screwing structure.

  On the other hand, in the flow rate control valve according to claim 1, the conventional valve body is divided into a shaft member having a driving force converting function and a valve member having a valve function, and the valve member is provided by an urging means. Is in contact with the shaft member. Therefore, although the shaft center of the valve member is constrained by the urging force of the urging means and the abutting of the shaft member, the urging force of the urging means and the abutting of the shaft member are compared with the conventional screwed structure. The binding by is significantly weaker. As a result, the degree of freedom of the axial center of the valve member is improved as compared with the conventional valve body.

  For this reason, the axial center of the valve member can be changed so as to substantially coincide with the axial center of the opening operation member. The risk of valve leakage can be reduced.

According to the flow control valve of the first aspect, the valve member has the only sliding shaft portion that is inserted into the predetermined cylindrical portion and is slidably supported in the axial direction. The shaft portion is in sliding contact with the inner peripheral surface of the cylindrical portion in three or more locations in the circumferential direction.
Thereby, since the inclination of the valve member is eliminated, the displacement of the valve member becomes smooth, and the amount of valve leakage is reduced.

  The flow control valve of the best mode 1 converts the rotational force applied from the stepping motor into an axial force, and abuts against the shaft member by a predetermined urging means and a shaft member that is displaced in the axial direction according to the axial force. And a valve member that is displaced in the axial direction in accordance with the urging force applied from the urging means and the axial force transmitted from the shaft member, and the valve is displaced by moving the shaft member in the axial direction. The opening of the flow path is manipulated by displacing the member.

In addition, the valve member has a single sliding shaft portion that is inserted into a predetermined cylindrical portion and is slidably supported in the axial direction, and the sliding shaft portion is formed on the inner peripheral surface of the cylindrical portion, It is in sliding contact with three or more locations in the circumferential direction.

[Configuration of Example 1]
The structure of the flow control valve 1 of Example 1 is demonstrated using FIG. 1 and FIG.
The flow control valve 1 converts the rotational force applied from the stepping motor 2 into an axial force, and uses this axial force to operate the opening of the flow path. For example, an engine (not shown) In order to control the amount of intake air during idle operation, it is arranged in an intake air passage for idle operation (referred to as bypass passage 3) that bypasses the throttle valve, and the opening degree of the bypass passage 3 is manipulated.

  As shown in FIG. 1, the flow control valve 1 converts a rotational force applied from the stepping motor 2 into an axial force, and a shaft member 5 that is displaced in the axial direction according to the axial force, and a spring 6. 5, and a valve member 7 that is displaced in the axial direction in accordance with the urging force of the spring 6 and the axial force transmitted from the shaft member 5. And the flow control valve 1 operates the opening degree of the bypass flow path 3 by displacing the valve member 7 by displacing the shaft member 5 in the axial direction.

  The stepping motor 2 includes, for example, a rotor (not shown) having a permanent magnet and a stator (not shown) having a field coil, and responds to a command from an ECU (not shown). When the field coil is energized, it has a known structure that generates a rotational force that rotates the rotor.

  The shaft member 5 is provided with a male screw 9 on the outer periphery, and the male screw 9 is screwed into a female screw (not shown) provided on the rotor. Moreover, the shaft member 5 is kept non-rotatable by a predetermined locking means (not shown). When the stepping motor 2 is energized and the female screw rotates together with the rotor, the rotational force applied from the rotor to the shaft member 5 is converted into an axial force, and the shaft member 5 is displaced in the axial direction by this axial force. .

  The valve member 7 is inserted into the flange portion 11 and the predetermined cylindrical portion 12 which are abutted against the tip of the shaft member 5 and biased by the spring 6 from the opposite side of the surface where the shaft member 5 abuts. A sliding shaft portion 13 is slidably supported in the axial direction. The valve member 7 is displaced in the axial direction together with the shaft member 5 according to the axial force transmitted from the shaft member 5 and the urging force of the spring 6.

  Here, the cylindrical portion 12 forms a part of the bypass flow path 3 and opens into the valve chamber 15 that accommodates the valve member 7 and the spring 6 to form a circular opening, and a part of the bypass flow path 3 is formed. Eggplant. Moreover, the cylindrical part 12 is provided coaxially with the rotating shaft center of the stepping motor 2 which faces the axial direction.

  The flange portion 11 is provided with a tapered seating surface 18 seated on the opening edge 17 that forms the opening 16 on the side opposite to the surface that receives the contact of the shaft member 5. That is, the seating surface 18 is provided so as to be inclined with respect to the plane α parallel to the opening edge 17. Then, when the seating surface 18 is seated on the opening edge 17, the valve member 7 fully closes the opening degree of the bypass flow path 3. The inclination angle of the seating surface 18 with respect to the plane α, that is, the taper angle θ is set to 45 ° or less.

  As shown in FIG. 2, the sliding shaft portion 13 is provided with four flanges 21 slidably contacting the inner peripheral surface 20 of the cylindrical portion 12 at equal angular intervals in the circumferential direction, and is slid at four locations in the circumferential direction. It touches. In addition, although the sliding shaft part 13 of Example 1 is divided into four places in the circumferential direction and is in sliding contact with the inner peripheral surface 20, it may be divided into three places and may be in sliding contact. You may make sliding contact. Further, the portion that is in sliding contact with the inner peripheral surface 20 does not need to be in the form of the flange 21 and can be freely selected.

[Effect of Example 1]
The flow control valve 1 according to the first embodiment converts a rotational force applied from the stepping motor 2 into an axial force, and abuts against the shaft member 5 by a shaft member 5 that is displaced in the axial direction according to the axial force and a spring 6. And a valve member 7 that is displaced in the axial direction in accordance with the urging force of the spring 6 and the axial force transmitted from the shaft member 5. The valve member is displaced by moving the shaft member 5 in the axial direction. 7 is displaced to manipulate the opening degree of the bypass flow path 3.
Thereby, the valve member 7 can be displaced without the shaft center being restrained by the screwed structure of the shaft member 5 and the rotor. For this reason, the valve member 7 can be displaced by making its own axis substantially coincide with the axis of the cylindrical portion 12 regardless of the axis of the rotor, thereby reducing the risk of valve leakage. it can.

The seating surface 18 is provided so as to be inclined with respect to the plane α.
Thereby, for example, even if a negative pressure is generated in the cylindrical portion 12 and the seating surface 18 is temporarily strongly in close contact with the opening edge 17, the seating surface 18 can be easily opened. Can be separated from. In addition, this effect becomes large when the opening edge 17 is provided in the planar shape perpendicular | vertical to an axial direction, as shown in FIG.

Further, the taper angle θ is set to 45 ° or less.
When the taper angle θ exceeds 45 °, the opening edge 17 bites into the seating surface 18 violently. Therefore, by setting the taper angle θ to 45 ° or less, such biting can be alleviated.

The only sliding shaft portion 13 is in sliding contact with the inner peripheral surface 20 of the cylindrical portion 12 in four locations in the circumferential direction.
Thereby, since the inclination of the valve member 7 is eliminated, the displacement of the valve member 7 becomes smooth, and the amount of valve leakage is reduced.

It is explanatory drawing which shows the structure of a flow control valve. (A) is a front view of a valve member, (b) is a top view of a valve member.

Explanation of symbols

1 Flow control valve 2 Stepping motor 3 Bypass flow path (flow path)
5 Shaft member 6 Spring (biasing means)
7 Valve member 12 Tubular part 13 Sliding shaft part

Claims (1)

A shaft member that converts the rotational force applied from the stepping motor into an axial force and is displaced in the axial direction in accordance with the axial force;
A valve member that is urged to abut against the shaft member by predetermined urging means, and that is displaced in the axial direction in accordance with the urging force applied from the urging means and the axial force transmitted from the shaft member; With
By displacing the shaft member in the axial direction, the valve member is displaced to manipulate the opening of the flow path,
The valve member has a single sliding shaft portion that is inserted into a predetermined cylindrical portion and is slidably supported in the axial direction,
The flow control valve is characterized in that the sliding shaft portion is in sliding contact with the inner peripheral surface of the cylindrical portion at three or more locations in the circumferential direction.

Images