KR200204719Y1 - Radial piston pump - Google Patents

Abstract

Radial piston pump according to the present invention is a spiral portion of the spiral cam member that causes the stroke of the piston to the left and right helix and the portion connecting these spirals to the curved portion and the maximum position of the piston, that is, top dead center is divided into four In this case, the discharge flow rate is overlapped by placing the bottom dead center at the boundary line between the 3rd, 4th and 4th and 4th quadrants, especially in the hydraulic pump having an odd number of pistons. Can be minimized. In addition, by adjusting the position of the top dead center of the spiral cam profile to compensate for the loss due to the compressibility of the fluid as well as the geometric flow rate pulsation characterized in that the discharge flow rate theoretically completely constant.

Description

Radial Piston Pump

The present invention relates to a radial piston pump that can significantly reduce the pulsation phenomenon and the pulsation noise of the discharge flow rate. In particular, the discharge flow rate of the radial piston pump having an odd number of pistons is made constant. In general, as shown in FIG. 9, the radial piston pump rotates the eccentric cam or cylinder block so that the piston inserted into the cylinder block causes the stroke to be driven based on the eccentric cam. Has a structure. The radial piston pump discharges fluids sequentially and independently while each piston performs a linear reciprocating motion. Each radial piston pump discharges fluid in the form of a sine wave. Therefore, when the discharge amount by a plurality of pistons overlaps, the shape becomes a superimposed sine wave. This happens. In general, the pulsation phenomenon of the discharge flow rate of the hydraulic pump is known to be due to the geometric characteristics or the loss due to the compressibility of the fluid. The pulsation state of the discharge flow rate by such two reasons is well shown in FIG. Since the pulsation phenomenon appears in the axial piston pump as it is, in order to reduce the flow rate pulsation, an axial ball piston pump is proposed in Korean Patent Application No. 99-55337 and PCT Application PCT / KR99 / 00746.

In the two applications, as shown in Fig. 72 of FIG. 11, a spiral plate using a spiral profile is applied, but in the present invention, a spiral cam having a spiral profile deployed in a circumferential direction is applied.

The present invention applies a spiral cam that circumferentially applies a spiral profile applied to the spiral plate of the axial ball piston pump of FIG. 11 instead of the radial pump using the conventional eccentric one cam of FIG. In order to improve and to solve the problem of durability degradation due to the point contact of the axial ball piston pump applied to the two applications, the purpose of the present invention is to make the pulsation characteristics of the discharge flow rate of the radial piston pump constant In anticipation of a quiet operation, instead of using a pintle valve or a ring valve generally applied to a radial pump, an axial piston pump is used and a valve plate having an elongated groove is used to reduce the radial pump, and to reduce the hydraulic pump geometry. Radial which can greatly reduce pulsation of discharge flow rate due to characteristics and compressibility of fluid To provide a stone pump.

In order to realize the object of the present invention, a lower housing coupled to the upper housing with the upper housing and the spiral cam having a port for injecting and discharging the fluid;

A drive shaft rotatably installed to penetrate the upper and lower housings;

A cylinder block coupled to the drive shaft and rotating together with the shaft inside the housing;

An odd number of pistons arranged in the cylinder block at equal intervals and arranged in a radial direction to enable a linear reciprocating motion;

A spiral cam which causes a stroke of the pistons by a spiral cam surface on which rollers (or balls) provided at one end of the pistons are positioned and is fixed between the upper housing and the lower housing;

It includes a valve plate located between the cylinder block and the upper housing,

In the spiral cam, an axial displacement of the left and right spirals of the spiral profile applied to the spiral plate of the axial ball piston pump, hereinafter referred to as spiral (left spiral, right spiral), is developed in a radial direction from the central axis. These spirals also provide a radial piston pump which is connected by a curved portion which is developed in the radial direction from the central axis, hereinafter referred to as curved portion.

1 is an assembly cross-sectional view of a radial piston pump using a spiral cam as a first embodiment of the present invention

Figure 2 is a schematic diagram showing a profile of a spiral cam applied to the first embodiment of the present invention

3 is a displacement and discharge flow rate diagram of one piston located in a spiral cam applied to the first embodiment of the present invention;

Figure 4 is a view for explaining the positional relationship of the seven pistons located in the spiral cam applied to the first embodiment of the present invention

5 is a view for explaining the speed relationship according to the position of the seven pistons in the radial piston pump using a spiral cam applied to the first embodiment of the present invention

6 is a view for explaining that the discharge flow rate becomes constant due to the sequential flow compensation performed by the seven pistons in the radial piston pump using the spiral cam applied to the first embodiment of the present invention.

FIG. 7A is a view for explaining the geometrical flow compensation of the first piston a and the fourth piston d in FIG. 5 according to the first embodiment of the present invention.

Figure 7b is a flow rate pulsation diagram when considering the influence of the compressibility of the fluid when seven pistons according to the first embodiment of the present invention when the flow is compensated geometrically from each other according to the principle of Figure 7a

8A is a sectional view showing a profile of a spiral cam according to a second embodiment of the present invention;

8B is a view for explaining that the first piston (a) and the fourth piston (d) compensate for the compressibility of the fluid to the loss flow rate in FIG. 5 according to the second embodiment of the present invention.

FIG. 8C is an overall flow rate pulsation diagram when seven pistons are flow-compensated with each other according to the principle of FIG. 8B according to the second embodiment of the present invention.

9 is a cross-sectional view of the radial piston pump using a conventional eccentric cam

10 is a pulsation state diagram of the discharge flow rate of the radial piston pump using an eccentric cam

11 is an assembled cross-sectional view of an axial ball piston pump of the prior art to which a spiral plate is applied using a spiral profile.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in more detail.

1 is an assembled cross-sectional view of a radial piston pump using a spiral cam member 30, wherein the upper housing member 2 and the spiral cam member 30 having a predetermined space therebetween have an upper housing member 2 therebetween. It is located in the space of the lower housing member 4 coupled to shield the inner space of the drive shaft member 6 and the upper and lower housing member rotated by a rotation generating means (not shown), a plurality of cylinder bores in the radial direction And a cylinder block member 10 having an eight.

The upper housing member 2 is provided with a port 12 for introducing a fluid and a port 14 for discharging the fluid.

The piston members 16 inserted in the cylinder bores 8 and linearly reciprocating, respectively, have a pocket 18 formed thereon, and a roller (or ball) member 20 is rolled on the pocket 18. The exercise is inserted.

Another pocket 22 is formed at the lower portion of the piston member 16 so that the piston member 16 always provides elastic force in the radial direction by the elastic member 24 positioned between the cylinder block members 10. I'm getting it.

The drive shaft member 6 penetrates through the lower housing member 4 and the cylinder block member 10 in order so that the tip thereof is inserted into the needle bearing member 26 assembled to the upper housing member 2 so as to be rotatable. .

The spline 28 is formed on the outer circumference of the drive shaft member 6, and the spline 28 is splined with the through portion of the cylinder block member 10 so that the cylinder block member 10 rotates together at all times when the drive shaft rotates. Configured to do so.

A spiral cam member 30 is installed between the upper housing member 2 and the lower housing member 4.

The spiral cam member 30 is formed on the inner circumference of the spiral 32 in which the axial displacement of the spiral applied to the axial ball piston pump of FIG. 11 is developed in the radial direction, and a cylinder is formed on the spiral cam surface 34. The roller (or ball) members 20 provided on the top of the piston members 16 inserted into the cylinder bore 8 of the block member 10 are placed circumferentially. The spiral cam member 30 is fixed between the upper housing member 2 and the lower housing member 4 by the bolt member 36. At this time, the cylinder block member 10 is supported by the spring member 40, the spring member 40 is in close contact with the cylinder block member 10 toward the valve plate member 38 having a suction and discharge passage in an elongated shape. There is no leakage between the cylinder block member 10 and the valve plate member 38 to make it slide. At this time, the spring member 40 is provided in the cylinder block member 10 toward the lower housing member 4 side and is supported by the collar 42 member.

2 is a schematic view of the spiral cam member 30 mentioned in FIG. The spiral cam member 30 has two spiral portions 44 positioned apart from each other and two curved portions 46 connecting these spiral portions.

One of the two spirals is the left helix 48 and the other is the right helix 50. The circumferential length of the helix is in the x-axis, and the radial displacement and the velocity are developed in the y-axis. .

The spiral is the stroke of the piston when the portion closest to the center point of the spiral cam member 30 is called the top dead center 52 and the furthest part is the bottom dead center 54.

The top dead center 52 and the bottom dead center 54 exist in each curved portion, and in particular, when the spiral cam member 30 is divided into four, the curved portion in which the top dead center 52 exists is shown in FIG. 2. 52) are formed in 1, 4 and 2, 4 quadrants so as to be biased toward the 2, 4 quadrant side, and the curved portion where the bottom dead center 54 exists is formed by the bottom dead center 54 at It is formed over 3rd and 4th and 4th and 4th quadrants to coincide with the boundary line. The displacement and speed diagram of one piston member 16 during one rotation of the cylinder block member 10 are as shown in FIG. 3, and the speed of the piston member 16 is displayed corresponding to the displacement.

This configuration makes the discharge section longer than the suction section. That is, the discharge section is longer than the discharge section of the conventional eccentric cam, as the top dead center of the curved portion corresponds to the distance deviated from the boundary line between the 1, 4 and 2, 4 quadrants.

Figure 4 shows the position of the seven pistons located on such a spiral cam surface.

Each of the pistons (a, b, c, d, e, f, g) is equally located on the helical cam surface, and the second, third and fourth pistons are discharged when the first piston is located at the bottom dead center. The spirals 44 and the curved sections 46 are designed so that the fifth, sixth and seventh pistons can be located in the suction section. And in Figure 4, while driving the discharge section is longer than the suction section, the left and right helix section is increased and the curve section is reduced, or the left and right helix section is reduced by increasing the curve section, etc. It can optimize the characteristics of noise and abrasion.

When the spiral cam member 30 is applied to the radial piston pump of FIG. 1 to rotate the cylinder block member 10 through the drive shaft member 6, the piston a discharges as shown in 1) of FIG. From the starting position, the speed is gradually increased, and at the same time, 2) and 3) of FIG. 5 have the same speed of the pistons b and c, and 4) of FIG. 5 starts to slowly decrease the speed of the piston d at the same time. At the same time, 5) of FIG. 5 slowly decreases the speed of the piston e in the suction section, 6) of FIG. 5 maintains the same speed in the suction section, and 7) of FIG. It shows that the speed is gradually increasing in the suction section.

It can be seen that the flow rate discharged by the operation of the pistons are sequentially overlapped as shown in FIG. 6 so that the pulsation of the discharge flow rate is eliminated and becomes constant.

1) to 7) of FIG. 6 show an overlapped state of the discharge flow rates by the seven pistons when the cylinder block member 10 rotates two times from the piston a to the piston g, and FIG. It explains the principle of being constant.

FIG. 7A shows that the flow rate is sucked out by two pistons, the first piston a and the fourth piston d. The overlap flow rate 56 compensates for the missing flow rate 58 so that the total discharge flow rate becomes constant. Can be. However, the flow rate pulsation still occurs as shown in Fig. 7B due to leakage due to the compressibility of the fluid.

Thus, a second embodiment of the present invention will be described in detail from Figs. 8A to 8C.

As shown in Fig. 8A, the discharge section is extended by extending the left spiral portion so that the top dead center 52 'is further biased into the second and fourth quadrants by a predetermined angle (k.) Than the top dead center 52 of the spiral cam of the first embodiment. To compensate for the loss of flow due to the compressibility of the fluid. Fig. 8b shows the principle, but it can be understood that the discharge flow rate pulsation can be made constant by comparing the excess discharge flow rate 60 with the compensating loss flow rate 62 due to the compressibility of the fluid. . Of course, the suction section is also reduced by a certain angle (k。). 8C shows the pulsation state of the total discharge flow rate when the seven pistons are rotated in contact with the spiral cam constructed by the second embodiment, and it can be seen that they are completely constant.

In addition, the pulsation state of the discharge flow rate of the radial piston pump having a constant pulsation state of the discharge flow rate is shown in FIG. 8C and a general eccentric circle cam.

As described above, the hydraulic pump according to the present invention has a constant flow rate pulsation by changing the camp profile, and can be applied to low noise and low pulsation for all applications in which a conventional radial piston pump is used. The plate-type valve which has a flow path and is used for an axial piston pump is applied, so the pump is small and can be used as an alternative to an axial piston pump.

Claims (4)

A lower housing coupled to the upper housing with an upper housing and a spiral cam member interposed therebetween for introducing fluid and discharging fluid; A drive shaft rotatably installed to penetrate the upper and lower housings; A cylinder block coupled to the drive shaft and rotating together with the shaft inside the housing; An odd number of pistons arranged at equal intervals on the cylinder block and arranged to allow piston movement; A spiral cam member inducing a stroke of the pistons and fixedly positioned between the upper and lower housings by a spiral cam surface on which roller (or ball) members provided at one end of the pistons are located; It includes a valve plate located between the cylinder block and the upper housing, The spiral of the spiral cam member includes a left spiral and a right spiral, and these spirals are connected by a curved portion, and when the spiral cam is divided into four quadrants, a bottom dead center is positioned at a boundary between the third and fourth quadrants. The top dead center is located at the position offset from the boundary line of quadrant 4 and 2,4 quadrant, so that the longer circumferential distance between the top dead center and the bottom dead center becomes the discharge section, and the short section becomes the suction section. Radial piston pump with improved geometric flow pulsation The method of claim 1, wherein the position of the top dead center of the spiral cam member is biased further to the second and fourth quadrant sides by a predetermined angle than the position of the top dead center of the spiral cam member used in claim 1 to compensate for the loss flow rate due to the compressibility of the fluid. Radial piston pump with improved pulsation characteristics of discharge flow rate. The radial piston pump according to claim 1, wherein the range of the left spiral section, the right spiral section, and the curved section of the spiral cam member can be freely adjusted to optimize driving characteristics, noise, and abrasion. The radial piston pump according to claim 1, wherein the curved portion has a spiral cam member formed over a discharge section and a suction section.