WO1999039127A1

WO1999039127A1 - Pressurized, closed lubrication and hydraulic oil system

Info

Publication number: WO1999039127A1
Application number: PCT/SE1998/001300
Authority: WO
Inventors: Tore Wiklund
Original assignee: Tore Wiklund
Priority date: 1998-01-28
Filing date: 1998-07-01
Publication date: 1999-08-05
Also published as: EP1049898A1; AU8137498A

Abstract

A closed, hoseless, pressurized lubrication and hydraulic oil system for a hydraulic piston-cylinder apparatus (1, 2), in which the cylinder part (1), with one end thereof (3, 5) is rotatably mounted in a stationary bearing block (7), and in which hydraulic oil is transported between the piston side (10) of the piston-cylinder apparatus and the piston rod side (11) thereof through telescopic tubes (21), and in which both the pressure lubrication system (24-30) for lubrication of bearings between the piston-cylinder apparatus (1, 2) and the stationary bearing block (7), and means (12-18) for supply of hydraulic fluid under pressure to the two sides of the piston-cylinder apparatus are provided in a bearing pin (6) about which the piston-cylinder apparatus is adapted to rotate.

Description

PRESSURIZED, CLOSED LUBRICATION AND HYDRAULIC OIL SYSTEM

The present patent application relates to a grease lubrication system combined with a system for transportation of hydraulic oil, and the invention is more particularly directed to such a lubrication and hydraulic oil system, which is formed as a closed and pressurized system which is fully sealed and eliminates the risk of spill of grease and hydraulic oil.

The invention has been developed especially in connection to hydraulic arms of the type which are rotated or are both swinged/turned and rotated about a bearing pin or a bearing ball, actuated by a piston-cylinder apparatus which at the bearing pin or bearing ball thereof is fixed in relation to a stationary bearing block.

The invention has been especially developed in connection to improvements of the type of hoseless hydraulic piston-cylinder apparatus, generally referred to as hydraulic cylinders or hydraulic arms which are shown for instance in the patent publication WO 83/0281 4 (in the name of the present applicant).

The invention is especially useful in connection to said type of hoseless hydraulic cylinders, and in the following it will be described with reference to axial motors of piston-cylinder type, especially hydraulic cylinders which are rotatable in one plane of a slide bearing or which are universally rotatable over a ball bearing.

PROBLEMS TO BE SOLVED

In many cases grease lubrication is made so that the machine, the vehicle etc. has to be stopped at predetermined intervals, and that new grease is filled in that the grease is forced into the lubrication places, either by tightening a grease cup, or by means of a grease injector until the lubrication place is filled up. This is done also in such types of machines which are used in connection to road and ground construction works, in forestry works, in agricultural works, for instance for tractors, digging machines, logging machines and other types of machines which are normally used in places where there is no near-by located place having service stations, repairing workshops etc.

Normally there are no means for checking the degree of filling at the lubrication places, and therefore grease or oil is introduced until grease or oil is forced out through one or more evacuation places at the terminal end of the lubrication or oil system. In machines and vehicles etc. of the said type which operate mobile outdoor a certain amount of grease or oil will be forced out and will be left in the nature. In other cases, especially in trucks and other mobile vehicles the lubrication system can be time programmed so that a grease pump is activated after a certain number of driven miles or at certain predetermined time intervals, etc., whereby grease is, in an automatic way, pressed into the lubrication place or places. Also in this case it is necessary that the lubrication place is evacuated so that grease can be forced through the entire lubrication system, and whereby also in this case a certain amount of grease is generally pressed out at the end of the lubrication system and is left at the road or in the nature.

Most machines of the said type which operate with movable arms, or other working implements are formed with flexible hoses for supply of hydraulic oil to the hydraulic piston-cylinder apparatus, in the following generally referred to as hydraulic cylinders. This has been considered the most simple structure, perhaps even necessary in order to give the hydraulic arms the desired mobility. The hydraulic hoses are subjected to very high stresses, both depending on the high pressure of the hydraulic oil, and also depending on the very frequent bending of the hoses, and also for reason that the hoses may be subjected to abrasion against adjacent objects. Therefore it happens, not so rarely, that the hydraulic hoses crack or burst straight across, whereby often great volumes of hydraulic oil is sprayed out into the nature.

There are great disadvantages involved in pressing or spraying out grease and oil and allowed same to stay in the nature, and the system also leads to unnecessary high consumption of grease and oil; the time-controlled grease lubrication systems also are rather expensive; and the manual grease lubrication system makes it necessary to lubricate the machine or the vehicle manually whereby the machine or vehicle has to be stopped at predetermined intervals. There are special problems involved for instance in underground working, like in mines, where the vehicles formed with hydraulic arms move over a relatively little distance, and whereby even small amounts of grease or oil, which has been pressed out, can lead to slipping accidents and other problems, and where it is of extreme importance that the lubrication and the supply of oil is made as good as ever possible so that no wear appears depending of lack of lubrication, since it is time consuming and expensive to transport the machines up to the ground level for service, maintenance and repairing.

PRIOR ART A system for long time lasting grease lubrication is known from GB-A-

1 ,185,718, used for a universally movable hydraulic arm operating with a ball bearing and a bearing socket, and in which the shaft of the bearings ball is formed with a supply chamber for a lubrication means and with a pressure means for continuously keeping the bearing surfaces of the bearing ball and bearing socket well lubricated.

The said patent solves the problem of providing a grease lubrication system which is formed so that there is normally no spill of grease into the nature, so that there is an optimum little consumption of grease at the lubrication places, so that the grease lubrication follows automatically and with a constant grease lubrication, so that the grease is pressed into the lubrication places with a constant pressure, so that the grease lubrication is made with long time action, and so that the machine or the vehicle must not be stopped recurrently for filling of grease.

The patent in question does not, however, solve the problem with leaking and cracked hydraulic hoses.

THE INVENTION

Therefore the object of the invention is to solve the problems involved in both two-dimensionally and universally movable arms actuated by hydraulic cylinders, both as concerns spill of lubrication grease, and also as concerns leaking, cracked or torn apart hydraulic hoses.

According to the invention the bearing pin for the bearing ball of the two-dimensionally or the universally movable arm is formed both with a pressurized, closed system for continuous lubrication of the bearing places between the bearing ball and the bearing sockets, and with means for pressurized, closed supply of hydraulic fluid to the two sides of the piston of the hydraulic piston-cylinder apparatus, without the need of using flexible hoses.

The supply of hydraulic fluid to the bearing pin is made by means of solid tubes, and the transportation of hydraulic fluid from said bearing pin to the piston rod side of the extendible piston is likewise made by means of solid tubes which are directly connected to a projecting part of the bearing pin.

For making it possible the turn/rotate the hydraulic cylinder universally in relation to the fixed bearing block the connection part between the bearing pin and the hydraulic tube extending between the two ends of the hydraulic cylinder can be formed with ball joints, through which hydraulic oil can flow in both directions.

Now the invention is to be described more in detail with reference to the accompanying drawings which disclose a lubrication system in a hydraulic piston-cylinder apparatus of hoseless type.

DESCRIPTION OF THE DRAWINGS

In the drawings figure 1 shows a hydraulic piston-cylinder apparatus of hoseless type in a partly cut open condition, which apparatus is formed with a closed, pressurized grease lubrication system and with hoseless means for supply of hydraulic fluid to the two ends of the hydraulic cylinder. Figure 2 is a diagrammatic side view of the apparatus of figure 1 , and figure 3 shows the opposite side of the hydraulic arm according to figure 2. Figure 4 is an enlarged view of the grease lubrication system according to the invention in a hydraulic arm having a ball joint for transmitting universal motion moments. Figure 5 shows a hydraulic arm having a slide bearing for transmitting rotary movements in one plane, and figure 6 shows, more in detail, the means for supply of lubrication grease and hydraulic fluid through the bearing pin to the movable hydraulic cylinder.

DETAILED DESCRIPTION

The hydraulic arm shown in the drawings comprises a cylinder part 1 , in which a piston 2 is displaceable. The cylinder 1 has a lower cylinder socket 3 and an upper cylinder socket 4. The lower cylinder socket 3 is formed with a cylinder ear 5 having a connection means for a bearing pin 6, which is mounted in a bearing block 7 which can be stationary in relation to the machine arm. In the case shown in figure 1 the bearing is a ball type bearing having a bearing ball 8, which is mounted in two annular ball bearing sockets 9 which are clamped to the cylinder ear 5.

HYDRAULIC FLUID SYSTEM

The hydraulic arm is special in that it is hoseless, and in that the hydraulic fluid is transmitted through the bearing pin 6 to and from both the piston side 10 and the piston rod side 1 1 . To this end the bearing pin has a first axial bore 12 extending from an outer pressure medium connection 13 halfway through the bearing ball 6. the bearing ball 6 has an all around extending slot 14, into which pressure medium is distributed through one or more radial bores 1 5 extending from the axial bore 12, and from there pressure medium is transmitted through a passageway 1 6 into the piston side 10 of the cylinder.

For transporting pressure fluid to and from the piston rod side 1 1 there is a slightly obliquely extending second bore 1 7 in the bearing pin 6, which bore 17, over connections 18, transmit hydraulic fluid into the lower end of a telescopic link 19. Over a ball joint 20 the hydraulic fluid is transmitted through a telescopic tube 21 and over a telescopic connection 22 having a ball joint 23, into the piston rod side 1 1 through the upper cylinder socket 4.

LUBRICATION SYSTEM

A lubrication system of the above described ball joint type, which is essential to the invention is shown most clearly in figures 4 and 6, and a corresponding lubrication system having a slide bearing is most clearly shown in figure 5. As evident from figure 4 the cylinder ear 5 is formed with two press nipples 24 (see figure 2), or one press nipple 24 and an evacuation plug. Said two connections are intended to make it possible to check that the entire grease lubrication system is filled up with lubrication grease. From the press nipple 24 distribution passageways 25 lead into the lubrication surfaces between the ball joint 8 and the bearing sockets 9, and from the ends of the bearing sockets 9 via radial passageways into a storage passageway 26, which opens in a pressure chamber 27 which is actuated by a piston 28 which is loaded by a biasing spring 29. A piston rod 30 to the piston 28, which projects outside the pressure medium connection 13 can be used as an indicator of the amount of grease remained in the pressure chamber 27. It is shown in the drawings that all ways for the grease from the lubrication nipple 24 to the pressure chamber 27 are sealed, so that no grease can escape from the system. The pressurized grease storage chamber 27 can be made so large that a filled up chamber can last for many days, weeks or months. The grease is pressed out, with practically constant pressure, to the lubrication surfaces between the bearing ball 8 and the bearing sockets 9. The apparatus shown in figure 5 differs from the above mentioned ball joint embodiment mainly only in that figure 5 relates to a slide bearing embodiment, in which the lubrication should be made between the slide surfaces between the bearing pin 6 and the bearing sockets 9. Otherwise the two embodiments are structurally analogous.

In figure 6 there is shown an alternative embodiment in which the hydraulic fluid from the piston rod side 1 1 is utilized as a source of pressure for the piston 28 in the pressure chamber 27. This is accomplished in that a branch conduit 31 connected at a place of the feeding side for the bearing pin 6, and in that said branch conduit 31 , over passageways 32, open in the cavity for the piston rod 30 through a specially designed pressure nipple 33. The pressure acts against the side of the piston formed eith the piston rod 30. The apparatus shown in figure 5 is suited for such fields of use in which the hydraulic arm can only rotate in a predetermined plane. In many cases the hydraulic arm can rotate/turn both sideways and in a predetermined plane of operation, whereby the joint place must be capable of receiving universal movements. In such cases the ball joint embodiment shown in figures 1 , 4 and 6 is best suited.

By forming both the closed, hoseless hydraulic system and the closed, pressurized lubrication system in the very bearing pin 6 there has been provided a simple and effective system which is wear resistant and practically maintenance free, and which has no projecting parts which can be damaged, as is usual in priorly known systems, and which in front of all eliminates the risk of spillage of grease and oil in the nature.

REFERENCE NUMERALS

1 cylinder part 21 telescopic tube

2 piston part 22 telescopic connection

3 lower cylinder socket 23 ball joint 4 upper cylinder socket 24 press nipple

5 cylinder ear 25 distribution passageway

6 bearing pin 26 storage passageway

7 bearing block 27 pressure chamber

8 bearing ball 28 piston 9 bearing socket 29 spring

1 0 piston side 30 piston rod

1 1 piston rod side 31 branch conduit

1 2 axial bore (first) 32 passageway

1 3 pressure medium connection 33 pressure nipple 14 slot

1 5 radial bore

1 6 passageway

1 7 bore (second)

1 8 connection 1 9 telescopic link

20 ball joint

Claims

8C L A I M S

1 . A closed, hoseless, pressurized lubrication and hydraulic oil system for a hydraulic piston-cylinder apparatus (1 , 2), in which the cylinder part ( 1 ), with one end thereof (3, 5) is rotatably mounted in a stationary bearing block (7), and in which hydraulic oil is transported through telescopic tubes (21 ) between the piston side (1 0) of the piston-cylinder apparatus and the piston rod side (1 1 ) thereof , characterized in that both the pressure lubrication system (24-30) for lubrication of bearings between the piston-cylinder apparatus ( 1 , 2) and the stationary bearing block (7), and means ( 1 2-1 8) for supply of hydraulic fluid under pressure to the piston-cylinder apparatus are provided in a bearing pin (6) about which the piston-cylinder apparatus is adapted to rotate.

2. A system according to claim 1 , characterized in that the pressure lubrication system comprises a storage chamber (27) arranged for being filled with lubrication grease, and means (28-39; 31 -33) for successively feeding a layer of grease to the actual surfaces to be lubricated.

3. A system according to claim 2, characterized in that the means for feeding grease to the surfaces to be lubricated comprises a pressurized piston (28) which over passageways (25, 26) directs grease to said surfaces to be lubricated.

4. A system according to claim 3, characterized in that the pressurized piston (28) is spring biased over a predetermined pressure, and in that the bearing surfaces are formed with sealed bearing sockets (9).

5. A system according to claim 3, characterized in that the pressurized piston (28) is loaded with a hydraulic fluid of a predetermined pressure over a branch conduit (31 -33) from the ordinary pressure conduit (1 7) leading to and from the piston-cylinder apparatus (1 , 2), which pressure is varied depending on the pressure that the pump motor for the hydraulic fluid transportation generates from start to stop.

6. A system according to any of the preceding claims, used for lubrication of two dimensionally rotatable arms having pressure lubricated slide bearings (figure 5), or for universally rotatable arms having pressure lubricated ball joint bearings (figures 1 , 4, 6), characterized in that the storage chamber (27) for the lubrication grease and the means for pressing out the lubrication grease to the places to be lubricated (for instance 8, 9) are provided in the bearing pin (6) by means of which the piston-cylinder apparatus (1 , 2) is rotatably or both rotatably and swingably mounted in a stationary part (7), whereby the storage chamber (27) for the grease is arranged axially in the bearing pin (6) and is in communication with the bearing places over co- operating passageways (25, 26) in the bearing pin (6).

7. A system according to any of the preceding claims, characterized in that the grease storage chamber (27) is arranged for being filled with grease, and alternatively for substituting the grease by new grease through one way lubrication nipples (24) which are available from outside the apparatus. 8. A system according to any of the preceding claims, characterized in that the means for supply of hydraulic oil comprises a pressure fluid connection (1 3), a first passageway (1 2) in the bearing pin (6) for supply of hydraulic fluid under pressure to the piston side (10) of the piston-cylinder apparatus (1 , 2) and a second passageway (1 7) in the bearing pin (6) for supply of hydraulic fluid under pressure to the piston rod side ( 1 1 ) of the piston-cylinder apparatus ( 1 , 2).

9. A system according to claim 8, characterized in that the first passageway (1 2) in the bearing pin (6) extends as far as to the axial centre of the bearing pin (6), through one or more radial bores ( 1 5) to an all around extending slot ( 14) in which the hydraulic fluid is distributed, and from which hydraulic fluid is supplied to the piston side (1 0) of the piston-cylinder apparatus.

10. A system according to claim 8 or 9, characterized in that the second passageway (1 7) in the bearing pin (6) is provided aside of the first passageway (1 2) and extends substantially axially through the bearing pin and is connected to a telescopic tube (21 ) transmitting hydraulic fluid to the piston rod side (1 1 ) of the piston-cylinder apparatus.

1 1 . A system according to claim 1 , characterized in that the telescopic tube (21 ) extending between the bearing pin (6) and the piston rod side (1 1 ) of the piston-cylinder apparatus is connected over a ball joint (20, 23) at both ends. 10

AMENDED CLAIMS

[received by the International Bureau on 08 April 1999 (08.04.99); original claims 1-11 replaced by amended claims 1-10 (3 pages)]

1 . An piston-cylinder apparatus ( 1 , 2) system having a closed, hoseless, pressurized hydraulic oil system, in which the cylinder part (1 ), with one end thereof (3, 5), is rotatably mounted in a stationary bearing block (7), and in which hydraulic oil is transported through telescopic tubes (21 ) between the piston side ( 1 0) of the piston-cylinder apparatus and the piston rod side ( 1 1 ) thereof , characterized in that the apparatus comprises, in addition to the hydraulic oil system, a closed, pressurized, hoseless lubrication system for lubrication of bearings between the piston-cylinder apparatus (1 , 2) and the stationary bearing block (7), that both the pressure lubrication system (24-30) , and means ( 1 2-1 8) for supply of hydraulic fluid under pressure to the piston-cylinder apparatus are provided in, or is connetected to, respectively, a bearing pin (6) about which the piston-cylinder apparatus is adapted to rotate. that the means for supply of hydraulic fluid comprises a pressuure fluid connection means at one side only of the piston-cylinder apparatus, from which projects a first passageway ( 1 2) in the bearing pin (6) for supply of hydraulic oil under pressure to the piston side ( 1 0) of the piston-cylinder apparatur (1 , 2) and a second passageway (1 7) in the bearing pin (6) for supply of hydraulic oil under pressure to the piston rod side ( 1 1 ) of the piston- cylinder apparatus, and in that said hydraulic oil passageways (1 2, 1 7) and the lubrication system (26-30) are separate from each other and extend substantially axially through the bearing pin (6).

3. A system according to claim 1 or 2, characterized in that the means for feeding grease to the surfaces to be lubricated comprises a pressurized piston (28) which over passageways (25, 26) directs grease to said surfaces to be lubricated.

AMENDED SHEET (ARTICLE 19J 11

5. A system according to claim 3, characterized in that the pressurized piston (28) is loaded by hydraulic fluid of a predetermined pressure over a branch conduit (31 -33) from the ordinary pressure conduit (1 7) leading to and from the piston-cylinder apparatus ( 1 , 2), which pressure is varied depending on the pressure that the pump motor for the hydraulic fluid transportation generates from start to stop. 6. A system according to any of the preceding claims, used for lubrication of two dimensionally rotatable arms having pressure lubricated slide bearings (figure 5), or for universally rotatable arms having pressure lubricated ball joint bearings (figures 1 , 4, 6), characterized in that the storage chamber (27) for the lubrication grease and the means for- pressing out the lubrication grease to the places to be lubricated (for instance 8, 9) are provided in the bearing pin (6) by means of which the piston-cylinder apparatus ( 1 , 2) is rotatably or both rotatably and swingably mounted in a stationary part (7), whereby the storage chamber (27) for the grease is arranged axially in the bearing pin (6) and is in communication with the bearing places over co- operating passageways (25, 26) in the bearing pin (6).

7. A system according to any of the preceding claims, characterized in that the grease storage chamber (27) is arranged for being filled with grease, and alternatively for substituting the grease by new grease through one way lubrication nipples (24) which are available from outside the apparatus.

8. A system according to any of the preceding claims, characterized in that the first passageway (1 2) in the bearing pin. (6) extends as far as to the axial centre of the bearing pin (6), through one or more radial bores ( 1 5) to an all around extending slot ( 1 4) in which the hydraulic fluid is distributed, and from which hydraulic fluid is supplied to the piston side ( 1 0) of the piston- cylinder apparatus.

9. A system according to claim 8, characterized in that the second passageway ( 1 7) in the bearing pin (6) is provided aside of the first passageway ( 1 2) and extends substantially axially through the bearing pin and is connected to a telescopic tube (21 ) transmitting hydraulic fluid to the piston rod side (1 1 ) of the piston-cylinder apparatus. 12

10. A system according to claim 9, characterized in that the telescopic tube (21 ) extending between the bearing pin (6) and the piston rod side (1 1 ) of the piston-cylinder apparatus is connected over a ball joint (20, 23) at both ends.