JPS63190986A - Driving force transfer part for valve pressure setting driving part - Google Patents

Abstract

PURPOSE:To prevent a locking state from occurring, by making the extent of resistance in a direction of rotation of an adjusting screw smaller at a time when overmovement is regulated at a moving end of the adjusting screw. CONSTITUTION:With rotation of a motor 6, the rotation is decelerated by a speed reducer 7 and outputted out of an output shaft 8, whereby an adjusting screw 4 is rotated, and an energized state in a pressure setting spring 1 is changed. When the adjusting screw 4 is moved down ward and reached to a lower limit position, a screwing portion between an external thread part 4a and a nut 5 comes into a state of being clamped, but since a thrust bearing 20 is interposed therein, such a fear that the adjusting screw 4 is stopped at the lower limit position and becomes unmoved is in no case caused. Even in the case of the adjusting screw 4 moving upward, such a fear that it comes to a stop at an upper limit position and becomes unmoved will not happen owing to another thrust bearing 21.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to a pressure reducing valve that adjusts the elastic force of a pressure setting spring that sets the pressure on the secondary side by changing the forward/backward position of an adjusting screw. Vacuum adjustment valve related to the drive force transmission part of the automatic pressure setting drive part that moves the screw forward and backward using an actuator.

It can be applied to pressure setting drives such as differential pressure valves (differential pressure regulating valves), relief valves, and secondary pressure regulating valves.

<Prior Art> The pressure setting section of a conventional pressure reducing valve generally connects one end of a male screw to one end of a pressure setting spring via a spring holder. A nut portion screwed onto the male thread in J contact is fixed, and the male thread is moved forward or backward by manually rotating it, and the elastic force of the pressure setting spring is adjusted depending on the forward/backward position. The other end of the pressure setting spring abuts or is connected to one side of the diaphragm so as to apply a set pressure, and a secondary pressure acts on the other side of the diaphragm. In addition,
As a pressure reducing valve, a change in the secondary pressure is detected, for example, by the tire flam changing convexly from the spring side to the secondary work side, and the change in the diaphragm is detected via the pilot valve or directly. The valve is opened to compensate for the pressure drop on the secondary side.

In contrast to such a manual pressure setting section, it has become possible to use an actuator, such as a stepping motor, to rotate the wire screw to move it forward and backward. This is so that the desired pressure setting state can be automatically set without manual operation by using an appropriate control section. A prototype was manufactured for this purpose, as shown in Fig. 4.

What is shown in FIG. 4 is a pressure setting drive unit for a steam pressure reducing valve, in which the upper end of a pressure setting spring l is in contact with the lower end of an adjusting screw 4 via a spring receiver 2 and a steel ball 3. By displacing the adjustment screw 4 in the vertical direction, the biasing state of the pressure setting spring 4 changes, and the set pressure is changed. 5 is fixedly provided with a nut, and the male threaded portion 4a of the adjusting screw 4 is screwed into this nut 5. 6 is a motor, 7 is a reduction gear, and 8 is an output shaft of the reduction gear. A spline shaft 9 is coupled and fixed so as to extend the output shaft 8, and the lower end of the spline shaft 9 is fitted into a fitting portion IO formed in the adjustment screw 4. The spline shaft 9 is provided with three grooves 9a. The fitting portion 1O has a cylindrical retainer 11 fixed in a circular hole to hold the steel balls 12 so that each of the steel balls 12 is inserted approximately halfway into each groove 9a. In this configuration, the rotation of the output shaft 8 is controlled by a spline shaft 9, a steel ball 12. The axial movement of the adjusting screw 4 is transmitted through the retainer 11 to the adjusting screw 4, or the axial movement of the adjusting screw 4 is transmitted to the groove 9a.
This is permissible because the steel ball I2 moves relative to it. Therefore, when the adjusting screw 4 is rotated by the rotation of the output shaft 9, the nut 5 and the male threaded portion 4a are screwed together, so that the adjusting screw 4 is rotated.
This means that the biasing state of the pressure setting spring 1, that is, the degree of compression or tension, is changed depending on the position of the adjusting screw 4.

<Problems to be Solved by the Invention> The configuration of the driving force transmission section of the pressure setting drive section shown in FIG. It is restricted by a stepped portion 4b provided at the top and a portion 13 of the main body opposite to the stepped portion 4b. Also,
The limit position of the upward movement of the adjustment screw 4 is regulated by the lower end surface 9b of the spline shaft 9 and the bottom surface 4c of the fitting portion 10 of the adjustment screw 4 facing this lower end surface. . That is, excessive movement of the adjustment screw 4 beyond a predetermined movement range is regulated. However, it turns out that this configuration has the following problems. In other words, when the adjusting screw 4 is moved downward and the stepped portion 4b and the portion 13 come into contact, since this is a surface contact, the nut 5 and the male threaded portion 4a are engaged in a locked state. It's easy to become. Therefore, when the adjusting screw 4 has moved to the limit of downward movement, it may not move even if the next torque to move it upward is applied from the output shaft 8. Further, even when the adjusting screw has moved to its upper limit, it may become locked due to the surface contact between the lower end surface 9b and the bottom surface 4c and may not move. When the spline shaft 9 is further pushed up 3, its upper end surface 9C and the main body portion 14 come into surface contact, resulting in an even stronger locking state, or an excessive thrust load is applied to the reducer 7 via the output shaft 8. It is also possible that damage may occur.

SUMMARY OF THE INVENTION An object of the present invention is to provide a driving force transmission section for setting the pressure of a valve that can restrict excessive movement of the adjustment screw out of the movement range so as not to become locked.

Means for Solving the Problems> The means of the present invention is to prevent excessive movement of the adjustment screw that adjusts the set pressure out of the predetermined movement range by using a fixed part that does not move in the forward/backward movement direction of the adjustment screw. It is characterized in that it is formed to restrict movement, and a ball is interposed between the fixed portion and the adjustment screw so as to reduce resistance in the rotational direction of the adjustment screw.

<Function> According to the present invention, a ball is interposed between the fixed part and the part abutting the fixed part at both end positions of the moving range of the adjusting screw, so that excessive movement or restriction is prevented at the moving end of the adjusting screw. When the adjustment screw is in a point contact state and the resistance in the rotational direction of the adjustment screw is small, it will not become locked.

<Example> A first example is shown in FIG. In the figure, parts equivalent to those in FIG. 4 are designated by the same reference numerals and their explanation will be omitted. The main difference from the one in Figure 4 is that the thrust ball bearing 20
．． 21 is provided, and the upper part of the adjustment screw 4 is extended upward to form a contact surface 4d.

The thrust ball bearing 20 is provided above the nut 5, and has an inner hole through which the lower part of the adjusting screw 4 passes so as not to prevent the adjusting screw 4 from moving within a predetermined movement range, and has a lower race 20a. An upper race 20 is fixedly provided on the main body portion 22 and abuts thereon via a ball 20b.
A contact member 23 is provided above the upper race 20c so as to rotate together with the upper race 20c, and the upper end 23a of the contact member 23 is connected to the stepped portion 4b of the adjusting screw 4.
is facing.

The upper end 23a and the stepped portion 4b are provided in a positional relationship that abuts each other and restricts the downward movement limit position of the adjusting screw 4.

The thrust ball bearing 21 is provided in a main body portion 24 from which the output shaft 8 protrudes, an upper race 21a is fixedly provided, and a lower race 21c that contacts this via a ball 21b is rotatably provided. , the lower race 21c is held in position at the -L end of the spline shaft 9 by connecting the spline shaft 9 to the output shaft 8. In the figure, 25 is a connecting bottle. The outer diameter of the spline shaft 9 is smaller than the outer diameter of the lower race 21c, and a portion of the lower surface of the lower race 21c faces the contact surface 4d of the upper end of the adjusting screw 4. The contact surface 4d and the lower surface of the lower race 21c are provided in such a positional relationship that they contact each other and restrict the upward movement limit position of the adjusting screw 4.

The pressure setting drive section of this pressure reducing valve is driven by the rotation of a motor 6, which is decelerated by a reducer 7 and output from an output shaft 8, and according to the rotation of the output shaft 8, an adjustment screw is rotated via a spline shaft 9. This causes the pressure setting spring 1 to be displaced in the vertical direction, thereby changing the biasing state of the pressure setting spring 1 via the steel ball 3 and the spring receiver 2. In that case, when the adjusting screw 4 moves downward and reaches the lower limit position, the stepped portion 4b of the adjusting screw 4 comes into contact with the upper end 23a of the abutting member 23. At this time, the threaded part between the male threaded part 4a and the nut 5 is tightened, but the return torque to loosen it is applied to the thrust bearing 20.
Because of the presence of this, it is smaller than the conventional one where this does not exist. Therefore, the adjusting screw 4 does not stop at the lower limit position and become immovable. Further, when the adjusting screw moves upward and reaches the upper limit position, the contact surface 4d of the upper end of the adjusting screw 4 comes into contact with the lower surface of the lower race 21c of the thrust ball bearing 21, as shown in the figure. In this case as well, the thrust bearing 2
1 will not cause it to stop at the upper limit position and become motionless.

In FIG. 0 showing the second embodiment in FIG. 2, the same parts as those in the first embodiment shown in FIG. The main difference from the first embodiment is that the spline shaft 9
The ball 30 is interposed between the lower end surface of the adjusting screw 4 and the bottom of the spline fitting part lO of the adjusting screw 4 facing the lower end surface, and the thrust ball bearing 21 is omitted and the adjusting screw 4
and the structure of the upper end of the spline shaft 9 is the same as that of the conventional one shown in FIG.

In this embodiment, when the adjusting screw 4 reaches the lower limit position, the thrust ball bearing 20 acts in the same manner as in the first embodiment to prevent the adjusting screw 4 from becoming stuck. Further, when the adjusting screw 4 reaches the upper limit position t, the lower end surface of the spline shaft 9 and the bottom of the spline fitting part 10 of the adjusting screw 4 come into contact via the ball 30, and the spline shaft 9 moves in the axial direction. As long as it is supported by a fixed part that does not move, the presence of the ball 30 prevents the adjustment screw 4 from becoming stuck at the upper limit position, with the same effect as the thrust ball bearing link 21 in the first embodiment. In this embodiment, since the thrust ball bearing 21 as in the first embodiment is not present, the output shaft 8 receives an upward thrust load from the spline shaft 9. Therefore, a configuration is required in which the output shaft 8 is supported within the reduction gear I17 by a thrust ball bearing.

Since such a configuration is quite commonly adopted when the output shaft 8 is used in a vertical position, the thrust ball bearing 21 may be omitted as in this embodiment. If the output shaft 8 is not supported by a thrust bearing, the configuration will be as shown in the third embodiment shown in FIG.

In FIG. 3, the only difference from the second embodiment is that the same thrust ball bearing 21 as in the first embodiment is added. This allows the ball 30 to be adjusted from the adjusting screw 4.
Since the thrust load acting on the spline shaft 9 can be received through the spline shaft 9, the decelerator 7 side will not be damaged even if the output shaft 8 is not supported by a thrust bearing.
The adjustment screw 4 does not stop at the upper limit position.

<Effects of the Invention> According to the present invention, the conventional problem of the adjustment screw stopping at the moving end of a valve having a pressure setting spring in which the adjustment screw of the pressure setting part of the valve is driven by an actuator is solved. be done. Therefore, it becomes possible to put into practical use a self-regulating valve in which pressure is automatically set in response to commands from the control section.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional front view showing the main parts of a first embodiment of the invention, FIG. 2 is a partially sectional front view showing the main parts of the second embodiment, and FIG. 3 is a main part of the third embodiment. FIG. 4 is a partially sectional front view showing a drive section of an adjusting screw of a pressure setting section of a conventional steam pressure reducing valve. l...Pressure setting spring, 4...adjustment screw, 4a...
...Male thread part, 5... Nut, 9b... Lower end surface of spline shaft (fixed part), 22.24... Main body part (fixed part), 20b, 21b, 30...
··ball. Patent applicant Chiinil Buoy Chemical Co., Ltd. Professor Satoshi Kiyoshiki and 2 other father-in-laws 2
figure

Claims (1)

[Claims] (1) The setting pressure of the valve is adjusted by rotating the adjustment screw and moving it forward and backward to change the biasing state of the pressure setting spring, and the adjustment screw is moved forward and backward by an actuator. In the pressure setting drive unit of the valve, the adjustment screw is formed so that a fixed part restricts the excessive movement when the adjustment screw advances or retreats out of its movement range, and the fixed part and the adjustment screw are connected to each other. 1. A driving force transmission section for a pressure setting drive section of a valve, characterized in that a ball is interposed between the adjustment screws so as to reduce resistance in the rotational direction.