JPH0246824B2 - FUATSUSEIGYOBEN - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a negative pressure control valve, and more particularly to a negative pressure control valve using a cam mechanism.

The negative pressure control valve defines two chambers inside by a diaphragm whose outer peripheral part is fixed to a housing and whose inner peripheral part is fixed to a swinging member, and the swinging member is displaced by negative pressure introduced into one chamber. A rod fixed to the swinging member is used to open and close the valve member. However, when attempting to operate a negative pressure control valve in response to mechanical displacement of an accelerator or the like for exhaust control, the above-mentioned negative pressure control valve is not suitable. In order to operate the negative pressure control valve accurately in response to a small displacement angle of the accelerator, etc., it is necessary to convert the small displacement angle into a large stroke, and this stroke can always be obtained as a constant value. Must be.

The purpose of this invention is to enable a negative pressure control valve to accurately respond to even the slightest mechanical displacement. Basically, the negative pressure control valve according to this invention operates at a constant angle. It has a cam body that rotates within a range and a driven body that contacts the cam body through a rolling contact, and a slight rotation of the cam body is converted into a linear motion of the driven body with a large stroke, and this linear motion is converted into a swinging motion. The signal is transmitted to the valve member to accurately open and close the valve member.

Embodiments of the invention will be described with reference to the accompanying drawings.

The negative pressure control valve 1 includes a hollow body 3 fixed to a substrate 2, a first port 4 fixed to the body 3 and connected to a negative pressure source such as an intake manifold, and an exhaust recirculation valve etc. A case 6 having a second port 5 is provided.

The internal space defined by the body 3 and the case 6 is divided into two chambers 9 by a diaphragm 8 whose outer circumferential edge is held between the contact surfaces of the body 3 and the case 6 and whose inner circumferential edge is in close contact with the swinging member 7. , divided into 10. One chamber 9 is a passage 1 bored in the peripheral wall of the body 3.
1 to form an atmospheric pressure chamber, and the other chamber 10 has a passage 12 connected to the first port 4.
It communicates with a negative pressure source through a negative pressure source to create a negative pressure chamber. The swinging member 7 has a stepped central through hole, with a narrow diameter hole 1
A plurality of slits 14 are formed in the inner wall of the tube 15, which is press-fitted into the passage 12 through the slits.
A fluid path is provided between the outer peripheral wall of the end portion and the inner wall of the hole. A valve member 18, which receives the biasing force of a spring 17, is disposed in a large diameter hole 16 of the central through hole, and the valve member 18 is seated on a stepped portion 19 of the central through hole.
The movement of the swinging member 7 is controlled by its end 20 and the plate 2.
1, and the swinging member 7 receives the biasing force of springs 22 and 23 arranged opposite to each other. For example, a cam mechanism 24 interlocking with an accelerator mechanism is disposed within the body 3, and one end of the spring 22 is seated on the cam mechanism 24.

In the state shown in FIG. 1, the negative pressure on the first port 4 side enters the hole 13 through the tube 15 and is transmitted to the second port 5 through the slit 14.
On the other hand, when the cam body 25 constituting the cam mechanism 24 rotates due to the movement of the accelerator, etc., the driven body 26 moves linearly, biases the spring 22, transmits this linear movement to the swinging member 7, and the driven body 26 moves linearly.
The swinging member 7 is raised against the urging force of 3 (when installed as shown). Valve member 18 is tube 1
When the opening 5 is closed, communication between the first port 4 and the second port 5 is cut off. Further, as the swinging member continues to rise, the valve member 18 separates from the step 19 of the central through hole of the swinging member 7 while the valve member 18 closes the opening of the tube 15 . As a result, the hole 16 connected to the atmospheric pressure chamber 9 is opened to the slit 14, and the second port 5 is brought into communication with the atmospheric pressure chamber 9. In addition, 27 is a filter, and 28 is a ventilation hole.

As shown in FIG. 2, the cam body 25 constituting the cam mechanism 24 includes a shaft 27 that rotates in accordance with the movement of an accelerator or the like, and the shaft 27 is connected to a cylindrical wall body 25A. The cylindrical wall body 25A has a top wall 29 and a bottom wall 31 connected to the top wall 29 via a step 30, and has an inclined cam surface 32 between one end of the bottom wall 31 and one end of the top wall 29. Combine with . At least three cam surfaces 32 are arranged at equal intervals.

The driven body 26 constituting the cam mechanism 24 has a circular plate portion 33 that receives the spring 22, and a plurality of arms 34 extending radially outward from the plate portion 33 and arranged at equal intervals. The number of arms 34 corresponds to the number of cam surfaces 32, and at least three are provided. A bearing 35 is arranged on each arm 34, and the bearing 35 is connected to the bottom wall 31 of the cam body 25.
and the cam surface 32 can be brought into rolling contact (fourth
(see figure) Instead of the bearing 35, a ball 36 may be used (see figure 5).

The cam body 25 is disposed within the body 3 so that the shaft 27 extends from the base plate 2 to the outside. The driven body 26 connects the rolling contacts 35 and 36 to the cam body 2.
5, and at least one of the arms 34 is disposed within the body 3 so as to engage with a guiding slit 37 formed longitudinally in the inner wall of the body 3. The driven body 26 receives the urging force of the spring 22, and its rolling contacts 35, 36
is brought into contact with the bottom wall 31 of the cam body 25 (see FIG. 1).

In the above-described configuration, when the shaft 27 rotates in response to the movement of the accelerator or the like, the rolling contact in contact with the bottom wall 31 of the cam body 25 rotates, but when it reaches the cam surface 32, the driven Since the arm 34 of the body 26 is prevented from rotating by the slit 37, the driven body 26 is moved linearly against the biasing force of the spring 22, and after a predetermined stroke, the swinging member 7 is moved and the valve member 18 is moved. Performs opening and closing operations.

The guide slit 37 of the driven body 26 is treated with tetrafluoroethylene or the like to reduce frictional resistance and smooth the movement of the driven body. By applying the cam surface 32, the driven body 26 can be largely displaced in response to a small amount of displacement from the accelerator, etc., so that the responsiveness of the swinging member 7 and the valve member 18 is improved. Since a rolling contact is used for the driven body, there is very little wear on the cam surface, and even under the biasing force of the spring 22, there is no wear and deformation of the cam surface 32.
The driven body 26 can always be accurately displaced.

As is clear from the above, in the present invention, a small displacement can be converted into a large displacement using the cam surface, so the rocking body can be linearly moved in accordance with the movement of the accelerator, etc., and the valve member can be opened and closed. Furthermore, since the cam body and the driven body are in rolling contact, there is no wear and deformation of the cam surface, and the driven body can perform accurate linear motion while receiving the biasing force of the spring.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an example of the present invention, FIG. 2 is a perspective view of a cam body, FIG. 3 is a perspective view of a driven body, FIG. 4 is a partial sectional view showing an example of a rolling contact, and FIG. The figure is a partial sectional view showing another example of a rolling contact. In the diagram: 1... Negative pressure control valve, 4, 5... Port, 7...
Swinging member, 8...Diaphragm, 18...Valve member, 2
2... Spring, 24... Cam mechanism, 25... Cam body, 26... Followed body, 32... Cam surface, 35, 36...
Rolling contact.

Claims (1)

[Claims] 1 A diaphragm whose outer circumferential part is fixed to the housing and whose inner circumferential part is fixed to the swinging member defines the interior into a negative pressure chamber and an atmospheric pressure chamber, and the negative pressure that opens and closes the valve member according to the movement of the swinging member. In the control valve, a rolling contact of a driven body that receives the other end of a spring whose one end is locked to the swinging member is slidable on a cam surface of a cam body, and the rotational movement of the cam body is controlled by Negative pressure control valve converts linear motion.