WO2018073620A1

WO2018073620A1 - Rotary piston pump

Info

Publication number: WO2018073620A1
Application number: PCT/IB2016/056247
Authority: WO
Inventors: Станиславс МИРОПОЛЕЦС; Павелс МИРОПОЛЕЦС
Original assignee: Станиславс МИРОПОЛЕЦС; Павелс МИРОПОЛЕЦС
Priority date: 2016-10-18
Filing date: 2016-10-18
Publication date: 2018-04-26
Also published as: EP3521624A1

Abstract

The invention relates to hydraulic and pneumatic pumps having a working rotor, which can be used for pumping liquid and gas between vessels or for supplying a working fluid for cooling, lubricating and hydraulic driving purposes, particularly in internal combustion engines. An increase in capacity, performance and operating accuracy with minimal surge by comparison with other types of pumps of the same dimensions and mass is achieved in that a novel design of a working chamber inside a sleeve is used in the present pump.

Description

ROTARY PISTON PUMP

Technical field

The invention relates to mechanical engineering and can be used for power drive, cooling and lubrication systems serving various mechanisms where increased accuracy in flow and pressure is required without significant pulsation in the stream, in particular in engines and devices for pumping liquid and gas between containers.

State of the art

Known trochoidal pump according to patent Nr. LV 15039 (WO / 2015/104597), comprising a housing with two fittings, an internal pumping mechanism with a shaft and a piston, two covers with an opening for a shaft support mounted on the ends of the housing, where the covers are machined along the inner end for sliding contact with the piston, inside the case there is a sleeve that has surface grooves, which are communication channels, to which channel holes are made in the sleeve body from the inner passage, the cross-sectional profile of which is a broken epitrochoid curve with the formulas: X = e / 7 (24sinx + 25sin3x), Y = e / 7 (24cosx + 2 5cos3x), where the free parameter is τ = 0.2t; moreover, the shaft has a cylindrical cam for movable landing of the piston with an eccentricity e to the axis of the shaft and an output part connected to the rotation drive; moreover, the piston has flat ends for sliding contact with the ends of the covers, a central hole for movable seating on the shaft cam and the outer surface formed by a hyprochoid with formulas in rectangular coordinates: X = е (5sinx - sin2x), Y = е (5cos τ + cos2x) , where the free parameter is τ = 0, ..., 2t.

Due to the appearance of a gap caused by the absence at some sites of contact between the inner epitrochoidal surface of the sleeve and hypotrochoidal surface of the piston, harmful overflow occurs. This leads to pump disadvantages such as pulsation up to 15% in supply and pressure and inability to work at high pressures.

Disclosure of the invention

The aim of the invention is to improve the accuracy of operation and efficiency of the pump, disclosed in WO / 2015/104597, while ensuring extremely low ripple and the ability to work at low and high pressures.

The stated goal is achieved by using a sleeve with a newly developed inner surface. This design improvement, combined with well-known designs, provides for the following. The sleeve from the ends is closed by covers and inserted into the housing, made in the form of a shell with inlet and outlet fittings. The covers are the supports of the cam shaft, through one of them the shaft shaft protrudes outward, allowing rotation in both directions to change the pumping direction. The processes of suction and discharge occur due to the fact that the contact lines of the piston with the sleeve divide the internal space into four variables by volume of the cavity. When the shaft and the piston rotate, the cavities are connected to the suction nozzle at the moment of their expansion, sucking in liquid or gas, and they are connected to the pumping nozzle at the time of contraction, displacing these substances. Stable pumping occurs.

Brief Description of the Drawings

Figure 1 shows one embodiment of a pump device in longitudinal and transverse section.

The proposed rotary piston pump contains: sleeve 1 having a through longitudinal passage 8, housing 2, shaft 3, piston 4, through cover 5, blind cover 6, cam 9 of shaft 3, surface grooves 10 on sleeve 1 for seals, inlet and outlet fittings 11 and 1, boss 12 , communication channels 13 and 13 "on the sleeve 1 and / or on the housing 2, channel openings 14 and 14

In accordance with the above structural and functional principle, the device of the main components and parts of the pump can be performed as follows.

The shaft 3, known for the above technical solution (WO / 2015/104597), has the following characteristics. Shaft 3 consists of sections with different sizes of external surfaces. The output section is supported on the through cover 5 through the bearing or flange. The middle section of the shaft 3 serves for a fixed fit of the cam 9. The inner end section of the shaft 3 is supported on the central part of the blind cover 6 through a sliding or rolling bearing. The output section of the shaft 3 is used to connect the power drive. The configuration of this section may vary depending on known connection methods. The shaft 3 should be equipped with a cam 9, which can be made in the form of a cylinder with a longitudinal hole. The longitudinal axis of the hole and shaft 3 is offset from the axis of the large cylindrical surface by an eccentricity e, which determines the parameters of the piston 4 and the contour curve of the cross section of the inner surface of the sleeve 1. The piston 4 is movably mounted on the cylindrical surface of the cam 9. The length of the cam 9 must be less than the length of the piston four.

The sleeve 1 serves as the main link of the pump, providing the above advantages, and is a device in which the rotary pumping mechanism is located. The outer surface of the sleeve 1 is stationary in contact with the inner surface of the shell of the housing 2 and preferably has five surface grooves: three for seals 10, and two are communication channels 13 and 13 "of the same pressure cavities inside the sleeve 1 through four channel openings 14 and 14 \ These grooves and channels can also be made on the housing 2. The distance between the communication channels 13 and 13 "should be equal to the distance between the holes 14 and 14" in the housing under the nozzle 11 and 11 ". The ends of the sleeve 1 have threaded holes for fastening the covers 5 and 6. Inside the sleeve 1, a through longitudinal passage 8 is made, the cross-section contour of which, similar to the above prototype (WO / 2015/104597), has two symmetry axes: long L = 14е and short 1 = 10e shown in section BB of FIG. Unlike WO / 2015/104597, the contour line of the cross section of the inner passage is a new curve derived for this pump and for use in other devices. This curve is given the name “Miropolec curve”, which has the following formulas in rectangular coordinates:

X = e [5 sin (r + ω) - sin (2r - ω) + sin3a],

Υ = ± e [S cos v + ω) + COS (2T - ω) + cos3o],

where ω = arc tg 5 ^ "^ 2 COST ' ^CB ° 6 ° A ^HbIH parameter τ =] -22 ° 8.54' ... + 22 ° 8.54 '[.

The Miropolec curve provides accurate contact with sliding and rolling of the piston relative to the liner in all areas.

The remaining links, known from the above prototype (WO / 2015/104597), have the following characteristics.

The piston 4 has an axial longitudinal hole for landing on the cam 9 of the shaft 3 directly, but movably or through sliding and rolling bearings. In the first case, the piston 4 or cam 9 of the shaft should be made of the corresponding antifriction material, for example, bronze, etc. The contour of the curve of the cross section of the outer surface of the piston 4 is a closed hypotrochoid curve with three vertices and a radius of the circumscribed circle equal to no. Formulas curve in rectangular coordinates: X = e (5 sin t - sin 2t), Y = e (5 cos t + cos 2t), where the free parameter t = 0, ..., 2π.

The housing 2 consists of a sheet sheath that extends outside the sleeve 1 and two bosses 12 that are hermetically connected to the sheath, one above each communication channel 13 and 13 "of the sleeve 1. The channels 13 and 13" can also be made on the housing 2. The bosses have threaded through holes holes for connecting the fittings 11 and 1. The distance between the axes of the holes should be equal to the distance between the communication channels 13 and 13 "on the sleeve 1.

The caps 5 and 6 serve to center the shaft relative to the sleeve 1 and to limit the longitudinal displacement of the piston 4. The end of the piston 4 should slide freely, but without gaps, along the inner end of the cap 5. This inner part of the cap 5 and 6 is inserted into the end bore of the sleeve 1, centering it, and has a groove under the seal on the centering surface. On the covers 5 and 6 there are simple mounting holes opposite the threaded holes on the ends of the sleeve 1. The covers 5 and 6 differ only in the central part. In the through cover 5 there is a central hole for placing the bearing or flange under the outgoing part of the shaft 3. In the blind cover 6 there is a central recess for the rolling or sliding bearing of the shaft 3.

The device must be equipped with o-rings made of a material resilient and resistant to the pumped substance.

Based on the details of the design of the device described above, the sequence of operation of the pump during pumping, for example, liquid, is analyzed below.

For the initial take the pump position shown in figure 1, taking into account the following conditions:

- one of the peaks of the piston 4 is located vertically in the upper position; - the shaft 3 rotates at a constant speed pz clockwise;

- the ratio of the rotational speeds of the piston 4 and the shaft 3 is: n ₄ / pz = 1/3. At any moment in time in the cross-section of the device, the piston 4 has four or three points of contact with the sleeve 1, which divide the space between the piston 4 and the sleeve 1 into variable volume parts.

When turning the shaft 3 with the cam 9 at an angle a clockwise, the piston 4, leaving position 7, will occupy the position 7 _a , shown in thin lines, turning around its axis by the angle oc / 3. In this case, a fluid is displaced from the cavities M and w, which through the channel openings 14 and the peripheral communication channel 13 (located behind the channel 13 ") enters the right-hand discharge fitting 11. At the same time, the cavities N and n expand, sucking the liquid through the other channel openings 14" and another circumferential communication channel 13 "from the left suction fitting 11". With further rotation of the shaft 3 and the piston 4, this incoming fluid is forced into the right-hand discharge fitting 11 as described above at the beginning of the process. This fluid pumping occurs continuously when the shaft 3 rotates in any position of the piston 4. When the shaft 3 rotates in the opposite direction - counterclockwise, the above fluid flow changes direction and pumping will occur in the opposite direction.

Obviously, in one revolution, the presented pump sucks in and further squeezes out more liquid (about twice) than the gears of the gear pump, conventionally inserted into the internal dimensions in figure 1 (due to the limited height of the teeth).

Claims

CLAIM

1. A rotary piston pump containing

(i) housing (2) with two fittings (11 and 11 "),

(ii) a shaft (3) provided with a cam (9) with an eccentricity e to the axis of the shaft (3) and an outer part configured to attach the shaft (3) to the rotation drive,

(W) piston (4) with a central bore for movable

landing on the cam (9) and the hypotrochoidal outer surface,

(iv) two covers (5 and 6) with an opening for the shaft support (3) mounted on the ends of the housing (2) and machined along the inner end for sliding contact with the piston (4),

(v) and a sleeve (1) placed inside the housing (2), provided with grooves (10) for seals and grooves for communication channels (13 and 13 ") characterized in that two channel openings are made in the body of the sleeve (1) ( 14 and 14 ") to each communication channel (13 and 13") from the inner passage, the cross-section contour of which is a curve with formulas in rectangular coordinates:

X = e [5 sin (r + ω) - sin (2r - ω) + sin3a],

Υ = ± e [5 COS (T + ω) + COS (2T - ω) + cos3o],

, „.., 5 sin 2T + 2sinr

where e is the shaft eccentricity (3), ω = arc tg ^ ₂ T-2COST '

free parameter τ =] -22 ° 8.54; + 22 ° 8.54 '[.

2. The pump according to claim 1, characterized in that the piston (4) has flat ends for sliding contact with the ends of the covers (5 and 6) and an outer surface, the cross section of which is a hyprochoid with formulas in rectangular coordinates:

X = e (5 sin τ – sin 2τ), Υ = e (5 cos τ + cos 2τ), where the free parameter is τ = 0, ..., 2π.