WO1992014056A1

WO1992014056A1 - Radial-piston pump

Info

Publication number: WO1992014056A1
Application number: PCT/DE1992/000044
Authority: WO
Inventors: Siegfried Hertell
Original assignee: Barmag Luk Automobiltechnik Gmbh & Co. Kg
Priority date: 1991-01-30
Filing date: 1992-01-25
Publication date: 1992-08-20
Also published as: EP0522116A1; ES2076746T3; JPH05505440A; DE59202858D1; EP0522116B1

Abstract

The radial-piston pump disclosed has a cylinder block in which the pistons are fitted so that they can move radially in a straight line. The cylinder block has a surface facing radially outwards on which cylinder head pots (8) are mounted so that they surround the pistons, forming a pressure-tight seal. The cylinder block, together with the cylinder head pots (8) mounted on it, is enclosed in an outer casing (1), with which it forms the outlet chamber of the pump.

Description

DESCRIPTION

Radial piston pump

The invention relates to a radial piston pump according to the preamble of claim 1.

This radial piston pump is known from DE-OS 39 30 248 (IP-1656).

The object of the invention is to equip the known radial piston pump with low wear, low pulsation and to ensure a simple construction.

The solution results from the characterizing part of claim 1. Its special feature is that a very large outlet space is created between the housing jacket and the cylinder housing, that the major part of the cylinders, namely the cylinder pots, can be manufactured as individual components and can be provided with the exhaust valves before they are mounted on the cylinder housing so that the cylinder pots have a larger diameter than the pistons and can therefore be installed without the risk of misalignment.

An exemplary embodiment is described below with reference to the drawings.

The radial piston pump is shown in cross section. The radial piston pump is arranged in a circular cylindrical housing jacket 1. The axis 2 is concentric with the housing jacket 1. The eccentric 3 can be rotated about the axis 2. On the Eccentric 3, a support body 4 is freely rotatable. The support body 4 has the shape of a polygon, the number of pages of which corresponds to the number of pistons. Each surface 5 of the support body 4 rests on the end face of a piston 6.

The pistons 6 are slidably guided in a guide housing (cylinder housing) 7. The guide housing is also polygonal in cross-section with regard to its outer shape and its inner shape, so that the guide housing 7 forms a polygon ring. In the illustrated case, the guide housing has cylindrical guide bores in the polygon flanks, which are aligned radially to axis 2. A piston 6 is guided in each guide bore. The thickness of the guide housing is less than the piston length of the pistons 6. The width of the interior 14 of this polygon ring is matched to the width of the support body 4 such that the inner polygon of the guide housing forms a stop for the polygon of the support body 4. Therefore, the support body 4 can not make a relative rotation to the cylinder housing 7.

The interior 14 of the guide body is connected to the inlet channel of the pump (not shown). The pistons 6 are designed as hollow cylinders, which are open on the radially outward-facing end face, but form a closed end face radially inward. Each piston 6 has an inlet window 13 on the side, which is shown only once in FIG. 1 and has a rectangular shape in order to ensure the largest possible inlet cross section with little piston movement.

The guide housing 7 is covered with cylinder pots 8 on the outer circumference. These cylinder pots are circular cylinders which are closed on one end face 17 and open on the other. Each cylinder pot can be connected to the guide body with individual screws. Another fastening possibility consists in passing the cylinder pots into the space between the outer jacket 1 and the guide body 7 Tensioned spring force. For this reason, the end face of each cylinder pot is bulged outward and designed to be resilient, so that it is resiliently supported on the outer casing 1. As an alternative or in addition, the housing shell 1 can also be pressed in the area of the support in a spring-elastic manner. Furthermore, alternatively or additionally, spring-elastic compression spring elements can be inserted between the cylinder pots and the outer jacket.

Each cylinder pot has radial outlet channels 12. Each cylinder pot is surrounded by a valve band 10, which is made of plastic or steel and elastically encloses the cylinder pot. Each valve strip 10 therefore acts as a check valve with respect to the outlet space 11, which is formed on the outer circumference of the guide housing and within the housing shell 1. This outlet space is very large and therefore acts as a damping space. The outlet space is connected to an outlet duct.

Each piston is supported against the end wall 17 of its cylinder pot by a compression spring 18. As a result, each piston is pressed onto the polygon side of the support body 4 facing it and is moved outwards by the wobbling movement of the support surface and inwards by the spring force 18. Due to the flat contact of the end face of the pistons on the polygon side, the support body 4 is prevented from rotating with the eccentric 3. If it - e.g. B. by pollution - but should come to a turning, the corner between the polygon surfaces, which has reached its radially outer dead center, in front of the opposite inner wall of the guide housing. The width of the eccentric in the axial direction is larger than the piston diameter. The inner wall thus acts as a stop that holds the support body 4. This again creates the relative movement between the eccentric and the supporting body, which dissolves the pollution. Now the support body 4 is pushed back by the spring force 18 of the pistons and the flat one Restored system between the polygon surfaces of the support body and the end faces of the pistons.

Screws could be used to fasten the cylinder pots on the guide body. This is shown in the cylinder pot shown above. A cylinder pot is shown at the bottom right, in which the cylinder pot has a bushing 16 on the end facing away from the end face, which has a thread on its outer circumference. The guide bore of the guide body 7 is expanded accordingly and also has a thread, so that the cylinder pot can be screwed into the guide body 7. When screwed in, the end wall 17 of the cylinder pot no longer touches the housing jacket 1.

Another type of attachment is that the end faces 17 of the cylinder pots 8 are resilient. This is shown for the other cylinder pots. The height of the cylinder pots is selected in this case so that the cylinder pots are resiliently supported on the one hand between the guide body 7 and on the other hand the inner circumference of the housing shell 1 and are pressed with their foot onto the outer polygonal surfaces of the guide body 7.

Instead of or in addition to the resilient design of the end face 17, a spring element, e.g. B. a disc spring between the end face 17 and the housing shell 1 and ensure the resilient contact of the cylinder pot 8 on the facing polygonal surface of the guide body 7.

In Fig. 2 further possibilities are shown to prevent the support body 4 from rotating. For the rest of the description of FIG. 2, reference may be made in full to the previous description of FIG. 1. In Fig. 2, a recess 19 is created in an end wall of the support body 4. A pin 20 protrudes into this recess 19, which is attached to the cover of the pump housing, not shown here. The pin 20 and the recess 19 are axially directed. Another alternative is indicated by dashed lines in FIG. 2. Here, the support body 4 has a radial recess 21 which lies outside the polygon surfaces and the contact surfaces between the piston and the polygon surfaces. A pin 22 protrudes radially from the cylinder housing 7 into this recess 21.

REFERENCE SIGN LISTING

Housing, housing casing, axis, eccentric support body, wings, piston, cylinder housing, guide housing, cylinder head, cylinder pot, front surface of valve, exhaust valve, damping chamber, exhaust chamber, exhaust inlet, inlet window, interior stop, inner wall, bushing, end faces, compression spring, recess, pin, recess, pin

Claims

PATENT CLAIMS

1. Radial piston pump, the pistons (6) of which are movable in a cylinder housing (7) with radial piston guides and are actuated by eccentrics (3) and whose cylinder housings (7) are enclosed by a housing jacket (1) and with this the outlet space (11) form, characterized in that the cylinder housing (7) is covered on its outer circumference in the region of the piston guides with cylinder pots (8) which protrude into the outlet space (11) between the housing jacket (1) and the cylinder housing (7) and the outlet openings (12) and the valves (10).

2. Pump according to claim 1, characterized in that the cylinder pots (8) are circular cylinders, that the outlet openings are radial holes, and that the cylinder pots are each surrounded on their outer circumference by a radial band as an outlet valve (10).

3. Pump according to claim 1 or 2, characterized in that each cylinder pot (8) with the cylinder housing (7) is screwed by screws.

4. Pump according to claim 1 or 2, characterized in that each cylinder pot as a bushing (16) can be used in the piston guides of the cylinder housing.

5. Pump according to claim 4, characterized in that the cylinder pots can be screwed into the piston guides of the cylinder housing by means of threads.

6. Pump according to claim 1 or 2, characterized in that the cylinder pots (7) between the housing shell (1) and the cylinder housing (7) by a radial spring are elastically clamped, either the radially outwardly facing end face (17) of each cylinder pot and / or the housing jacket (1) is designed as a spring in the region of each cylinder pot and / or radially elastically flexible spring elements can be inserted between the housing jacket and the cylinder pot end face (17).

7. Radial piston pump according to the preamble of claim 1, in particular according to one of the preceding claims, characterized in that a support body is arranged on the eccentric of the pump, which is designed as a polygon, and that stops are provided in the cylinder housing, which in the movement circle of the polygon corners of the support body, but do not protrude into the movement circle of the center lines of the polygon surfaces of the support body.

8. Pump according to claim 7, characterized in that the stops are formed in that the cylinder housing is formed in the inner cross section as the support body-like polygon, the difference in diagonals being smaller than the eccentricity.