TWI422764B - Spool-type constant-flow valve - Google Patents

Description

Slider type flow valve

Hydrostatic bearing, equal flow valve

When the input pressure keeps the fixed output pressure as the working load changes, the pressure difference actuation mechanism of the equal flow valve makes the throttle length become smaller as the outlet pressure increases, reducing the flow resistance and making up for the pressure reduced by the increase of the outlet pressure. Poor; on the contrary, the export pressure is reduced, The actuating mechanism increases the throttling length, increases the flow resistance, and compensates for the increased pressure difference due to the decrease in outlet pressure; thus maintaining the flow constant.

There are three types of conventional equal flow valves, the first type being illustrated in Figure 1 (a), quoted on page 22 of Bassani, R., Piccigallo, B., Hydrostatic Lubrication, Elsevier Science Publishers BV, Amsterdam, (1992). 2.11.

The second type is illustrated in Figure 1 (b) and is quoted in Figure 12 on page 20 of Rippel, HC, Cast Bronze Hydrostatic Bearing Design Manual , Cast Bronze Bearing Institute, Inc., Cleveland, Ohio (1964).

The third type is illustrated in Figure 1 (c), quoted in Chen Yansheng, Principle and Design of Hydrostatic Support , National Defense Industry Press, Beijing (1980), Figure 3-12 on page 47.

A sliding rod type flow valve, which is composed of a sliding rod, a spring, a valve body and an end cover, uses a sliding rod to throttle, as shown in FIG. 2, the oil supply pressure is used as an inlet pressure, and the outlet pressure is used as a working pressure, The balance of the inlet pressure, the outlet pressure and the spring force on the ends of the sliding rod and the balance piston, adjusting the effective throttle length of the sliding rod, and controlling the flow rate to a constant value so that the flow rate does not change due to the change of the working pressure; The working principle is as follows:

Flow through the throttle bar throttling length among them For the slider throttle constant, d _s and l ₀ are the diameter and length of the slider, g _s is the gap between the slider and the hole, μ is the oil viscosity coefficient, and R ₂ is the initial flow resistance through the entire length of the slider. The dotted line shows the slider and piston position of the original displacement, and P _r and P _s are the output and input pressure, respectively. For the pressure ratio, x is the sliding rod displacement, which is proportional to the output pressure and the net force of the spring preload force, as shown below: Where C _s is the proportional coefficient of displacement, P ₀ is the initial pressure acting on the right end of the equilibrium piston; substituting equation (2) into equation (1) and dividing each by P _s R ₂ ^-1 among them It is a dimensionless displacement coefficient. When the flow rate is equal to = fixed value, numerator and denominator (1- ) should be eliminated, so the denominator of equation (3) can be broken down as follows: when When the upper right side of the upper equal sign becomes 1 in the right parenthesis So the above formula is simplified Equation (5) reveals that the flow rate does not change due to the output pressure, so the design conditions for maintaining the constant value are as follows: among them and The correspondence between the fixed values and the fixed values is shown in Figure 3. will and The design conditions for substituting the above equation to satisfy the equal flow rate are as follows: C _s (P _s -P ₀ )-1= l ₀ (6b)

The equal flow rate controlled by it is calculated by equations (1) and (3) as follows:

A spool-type flow valve with preloading, acting on the free end face of the balance piston using a preload adjustment mechanism With proper pre-pressure to match the length of the slider, the spring constant, and the area of the piston, the flow can be controlled to a constant value so that it does not change due to changes in operating pressure.

The pre-pressure adjusting mechanism is composed of a pre-pressing washer, a spring, a spring end cover and a valve body itself, the pre-pressing washer is made of a male thread, the outer end of the piston hole of the valve body is made with a female thread, and the pre-pressing washer is screwed in. Inside the piston bore of the valve body, it compresses the spring, adjusts the position of the pre-pressure washer to the required pre-pressure, and locks the spring end cap to the outside.

The present invention is a "slider type equal flow valve" which is composed of a slide bar 31, a spring 14, a valve body 18, an outlet end cover 341 and a spring end cover 342, and is throttled by a slide bar 31, as shown in Fig. 2. It is shown that the oil supply pressure is used as the inlet pressure, and the outlet pressure is the working pressure, and the force balance achieved by the inlet pressure, the outlet pressure and the spring force on both ends of the slide rod 31 and the balance piston 33 adjusts the effective throttle of the slide rod 31. The length and control flow are fixed values and are not changed due to changes in working pressure.

The sliding rod 31 is integrally formed with the balance piston 33, and moves together in the valve body 18. The valve body 12 is formed into a hollow cylinder body, and one end inner hole is formed into a sliding rod valve hole 32, and the sliding rod 31 is accommodated for translation. The length is equal to the sliding rod, and the inner hole at the other end is made into a piston hole 35. The balance piston 33 is internally translated, and the valve body 18 is formed with a radial throttle outlet 12 and an oil supply inlet 11, and the throttle outlet 12 is formed at the end of the spool valve bore 32, and the oil supply inlet 11 is adjacent to the oil inlet 11 The valve body where the piston hole 35 of the slider valve hole 32 is located, the end surface of the slider valve hole 32 of the valve body is closed by the outlet end cover 341, the other end is closed by the spring end cover 342, and the spring end cover 342 is installed between the balance piston 342 and the balance piston 33. The spring 14, the oil supply pressure acts on the end of the balance piston 33 at the end of the slide bar 31, the working pressure acts on the free end face of the slide bar 31, and the force of the spring 14 acts on the free end face of the balance piston 33, the force achieved by the three. The balance displaces the slide bar 31 and the balance piston 33, changes the length of the slide bar 31 in the slide valve hole 32, and is used to adjust the effective throttle length of the slide bar 31 to adjust the oil supply from the oil supply inlet 11 to the throttle outlet. The flow resistance of 12, the oil supply is throttled from the oil supply inlet 11 through the length of the slide rod 31 in the slide valve hole 32, and the preloading adjustment mechanism shown in Fig. 4 and the preload washer 36 shown in Fig. 5 are used. The preloaded spiral capillary module 40 can be adjusted to give an appropriate preload on the free end face of the balance piston 33. , A length, a constant of the spring 14 with the slider 31, the balance piston 33 and the free end area, the flow is controlled to a constant value, it does not work due to changes in pressure varies.

In the description of the invention, the design parameter condition of the equation (6b) is equal flow rate, and the equal flow value is obtained as shown in the formula (7). According to the two-type design, an implementation of one of them is as follows: when applied to the balance piston 33 pre-pressure P ₀ =100,000Pa, oil supply pressure P _s =10 ⁶ Pa, unit spring displacement coefficient C _s =4×10 ^-5 mm/Pa, the length of the valve stem 31 should be 35mm, the slide rod 31 and The gap between the valve hole 32 of the slider is 500μm, the diameter of the stem is 20mm, and the viscosity coefficient of the oil is μ=0.01Pa. When s, the constant flow rate of the equal flow valve is 392.5 cc / min.

The pre-pressure adjusting mechanism of the present invention uses the pre-pressure washer 36. As shown in FIG. 4, the pre-pressure washer 36 is formed with a male screw, the outer end of the piston hole 35 of the valve body 18 is formed with a female thread, and the pre-pressure washer 36 is screwed into the valve body. The spring 14 is compressed within the piston bore 35. The more the preload washer 36 is screwed in, the greater the preload pressure applied to the spring 14, the position of the preload washer 36 is adjusted to the desired preload, and the spring is externally locked. The end cap 342 completes the adjustment of the pre-pressure.

11‧‧‧ Oil supply entrance

12‧‧‧ throttle exit

13‧‧‧ piston rod

14‧‧‧ Spring

15‧‧‧port piston

16‧‧‧Back pressure piston

17‧‧‧Adjustable constant throttle valve

18‧‧‧ valve body

191‧‧‧Inlet regulating valve port

192‧‧‧Exit adjustment valve port

20‧‧‧throttle piston

211‧‧‧Cylindrical stem

212‧‧‧Cone stem

22‧‧‧Constant throttle valve hole

23‧‧‧Exit valve seat

31‧‧‧ Slider

32‧‧‧Slider valve hole

33‧‧‧balanced piston

341‧‧‧Export end caps

342‧‧‧Spring end cap

35‧‧‧Piston hole

36‧‧‧Pre-pressure washer

37‧‧‧ female thread

Figure 1 Construction diagram of the prior art

(a) Export-regulated export constant-throttle dual-variable pressure feedback type

(b) inlet adjustment outlet constant throttle dual variable pressure feedback type

(c) Export regulation inlet constant throttle outlet variable pressure feedback type

Figure 2 Design and construction diagram of the slider type flow valve

(a) Displacement of the slide bar and the balance piston

(b) Slider and balance piston in the initial position

Fig.3 Design conditions and equal flow rate of equal flow valve with design parameters

Figure 4: Pre-pressed slide-type equal flow valve

11‧‧‧ Oil supply entrance

12‧‧‧ throttle exit

14‧‧‧ Spring

18‧‧‧ valve body

31‧‧‧ Slider

32‧‧‧Slider valve hole

33‧‧‧balanced piston

341‧‧‧Export end caps

342‧‧‧Spring end cap

35‧‧‧Piston hole

Claims (1)

A "sliding rod type equal flow valve" is composed of a sliding rod, a balance piston, a spring, a valve body, an outlet end cover, a pre-pressure adjusting mechanism, and a spring end cover, and the sliding rod is integrated with the balance piston. Moving together in the valve body, the valve body is made into a hollow cylinder body, and one end inner hole is made into a sliding rod valve hole, and the sliding rod is accommodated for translation, and the length thereof is equal to the sliding rod, and the other end inner hole accommodates the balance piston to translate. The valve system has a radial throttle outlet and an oil supply inlet, the throttle outlet is formed at the end of the sliding valve hole, and the oil supply inlet is formed in the valve body of the piston adjacent to the valve hole of the sliding rod, and the sliding rod of the valve body The valve end is closed by the outlet end cover, the other end is closed by a spring end cover, and a spring is installed between the spring end cover and the balance piston, the oil supply pressure acts on the end of the balance piston at the slide bar, the working pressure acts on the end face of the slide bar, and The spring force balances the free end face of the piston, and the force balance achieved by the three causes the slide rod and the balance piston to be displaced, and the length of the slide rod in the valve hole of the slide rod is changed, and the effective throttle length of the slide rod is adjusted to be adjusted. Oil supply from entrance to exit section The oil supply is throttled from the supply inlet through the length of the slide rod in the valve hole of the slide rod, and a pre-pressure adjustment mechanism is used to give an appropriate pre-pressure on the free end surface of the balance piston to match the length of the slide rod, the spring constant, And the piston area, the flow rate can be controlled to a constant value so that it does not change due to the change of working pressure; the pre-pressure adjusting mechanism uses a pre-pressure washer, the pre-pressure washer has a male thread, and the piston hole of the valve body is the outermost The female thread is made at the end, and the pre-pressure washer is screwed into the piston hole of the valve body to compress the spring, adjust the position of the pre-pressure washer to the required pre-pressure, and lock the spring end cover outside.