Machine arrangement

Abstract

A machine arrangement comprising a crankshaft which is supported by at least one roller bearing including bearing rings and roller elements between the bearing rings, wherein the roller bearing is connected with a device for delivering of a lubricant to the area of rolling contact between the bearing rings and the roller elements. To improve the supply of lubricant to the roller bearing and to supply the right amount of lubricant in dependence of the temperature of the roller bearing, the device for delivering of the lubricant comprises a lubricant reservoir and a flow path from the lubricant reservoir to the area of rolling contact, wherein a valve element is arranged in the flow path for controlling at least one of a flow of lubricant and a pressure of lubricant in dependence of the temperature of at least one of the roller bearing and the valve element.

Claims

1. A machine arrangement comprising a crankshaft which is supported by at least one roller bearing with bearing rings and roller elements between the bearing rings, wherein the roller bearing is connected with a device for delivering a lubricant to an area of rolling contact between the bearing rings and the roller elements, a lubricant reservoir integral with the device for delivering of the lubricant; a flow path from the lubricant reservoir to the area of rolling contact integral with the device for delivering of the lubricant, and a valve element arranged in the flow path wherein the valve element is adapted for controlling at least one of a flow of lubricant and a pressure of lubricant in dependence of a temperature of at least one of the roller bearing and the valve element, the valve element comprising a valve housing defining an opening to a first bore therein such that the opening is located at an upstream end of the first bore, the flow path traversing the valve housing through the opening and the first bore, a filter disposed in the flow path upstream of and in contact with the valve housing so as to cover the opening therein, wherein the filter substantially prevents any non-lubricant material from entering the opening of the valve housing, the valve element further comprising a flow restriction element which is biased by a spring element, the spring element biasing the flow restriction element proximate to a downstream end of the first bore, wherein a spring force of the spring element, which is exerted onto the flow restriction element, is dependent on the temperature of the at least one of the roller bearing and the valve element such that the at least one of the flow of lubricant and the pressure of lubricant is varied upon changes of the temperature without reliance on any sensor data.

2. The machine arrangement according to claim 1, wherein the valve element is designed to increase the at least one of the flow of the lubricant and the pressure of the lubricant with rising temperature of the at least one of the roller bearing and the valve element.

3. The machine arrangement according to claim 1, wherein the flow restriction element is a ball which cooperates with a seat wherein the seat is machined into the valve housing.

4. The machine arrangement according to claim 3, wherein the seat has a conical surface.

5. The machine arrangement according to claim 1, wherein the spring element consists of a material which has a coefficient of thermal expansion which is different from the coefficient of thermal expansion of surrounding parts of the valve element.

6. A machine arrangement comprising a crankshaft which is supported by at least one roller bearing with bearing rings and roller elements between the bearing rings, wherein the roller bearing is connected with a device for delivering a lubricant to an area of rolling contact between the bearing rings and the roller elements, a lubricant reservoir integral with the device for delivering of the lubricant; a flow path from the lubricant reservoir to the area of rolling contact integral with the device for delivering of the lubricant, and a valve element arranged in the flow path wherein the valve element is adapted for controlling at least one of a flow of lubricant and a pressure of lubricant in dependence of a temperature of at least one of the roller bearing and the valve element, the valve element further comprising a flow restriction element which is biased by a spring element, wherein a spring force of the spring element, which is exerted onto the flow restriction element, is dependent on the temperature of at least one of the roller bearing and the valve element, wherein the flow restriction element is a ball which cooperates with a seat wherein the seat is machined into a valve housing, wherein the spring element is designed as a sleeve with a hollow-cylindrical geometry, and wherein the ball is arranged at one axial end of the spring element.

7. The machine arrangement according to claim 1, wherein the lubricant is oil.

8. The machine arrangement according to claim 7, wherein the lubricant reservoir is a main oil gallery of the machine arrangement.

9. The machine arrangement according to claim 1, wherein the machine arrangement is a combustion engine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The drawings show an embodiment of the invention.

(2) FIG. 1 shows a schematic front view of a combustion engine with its crankshaft and

(3) FIG. 2 shows detail Z according to FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

(4) In FIG. 1 a machine arrangement 1 being a combustion engine is shown. The combustion engine 1 has a crankshaft 2 which is supported by a plurality of roller bearings; only one of the roller bearings 3 is depicted in a sectional front view in FIG. 1 (the axis of the crankshaft is perpendicular to the paper plane).

(5) The roller bearing 3 has an outer bearing ring 4 and an inner bearing ring 5. Between the bearing rings 4, 5 roller elements 6 are arranged, which are cylindrical rollers in the present embodiment.

(6) During the operation of the combustion engine 1 the temperature varies in dependence of the load situation of the engine. Thus, the temperature of the roller bearing 3 varies as well and respectively.

(7) To supply the roller bearing 3 with a sufficient amount of lubricant, i. e. oil in the present embodiment, the combustion engine 1 is equipped with a device 7 for delivering oil to the roller bearing 3. The device 7 comprises a lubricant reservoir 7 which is the main oil gallery of the combustion engine and a flow path 7 which extends from the oil gallery 7 to the region of the rolling contact 8 between the roller elements 6 and the raceways of the bearing rings 4, 5.

(8) For controlling the flow rate of oil into the region of rolling contact 8 and/or for controlling the pressure of the oil accordingly a valve element 9 is arranged in the flow path 7 before the flow path 7 ends in the region of the rolling contact 8.

(9) The valve element 9 is designed in such a manner that the flow rate through the flow path 7 is controlled such that more oil flows when the temperature of the roller bearing 3 and thus the temperature of the valve 9 (which is arranged adjacent to the roller bearing 3) gets higher. On the other hand, the flow rate is reduced when the temperature of the roller bearing 3 and thus of the valve element 9 is falling.

(10) A valve element 9 which has this property is shown as an example in FIG. 2.

(11) The valve element 9 has a valve housing 13. In the housing 13 first and second coaxial bores 15 and 16 are machined. The first bore 15 has a bigger diameter than the second bore 16. The transition zone between the two bores 15, 16 is formed by a seat 12, which has a conical surface. In the first bore 15, a ball 10 is arranged which forms a restriction element for the flow rate which passes the flow path 7.

(12) An end section of the ball 10, which is remote from the second bore 16, is arranged on a spring element, which is a sleeve 11 with a hollow-cylindrical base geometry. When the arrangement is assembled, the lower end of the sleeve 11 lies flush with a mounting plane 17 of the housing element of the bearing. That is, due to the geometry of the first and second bores 15, 16, the seat 12, the ball 10 and the sleeve 11 forming the spring element, the ball is pressed with a certain spring force F onto the seat 12. So, the flow of oil through the flow path 7 and the respective oil pressure is restricted.

(13) The material of the sleeve 11 is chosen in such a way that the Young's modulus (i. e. the elastic modulus in N/mm2) falls quite significantly when the material is warmed up. A material is preferredspecifically an elastomer materialwhich exhibits a drop in the elastic modulus of at least 15% when the material is warmed up from room temperature (20 C.) to 250 C.

(14) Due to this effect, the spring force F drops accordingly when the valve element 9 is getting warmer. Consequently, the ball 10 is then pressed with less force against the seat 12, so that more oil can pass the flow path 7; the flow rate is thus rising.

(15) To make sure that no contaminants reach the rolling contact region 8 a filter element 14 is arranged in the flow path 7 just before the valve housing 13.

(16) Of course, also other designs are possible to obtain the desired behavior of the valve element 9, i. e. that the flow rate rises with rising temperatures of the bearing 3 and the valve element 9 respectively.

(17) For example the coefficient of thermal expansion can be used to modify the opening between the ball 10 and the seat 12. As the coefficient of thermal expansion is bigger for elastomer materials than for steel, it is necessary in this case to choose another design concept. For example it is possible that a thermally expanding elastomeric element presses the annular gap between the ball 10 and the seat 12 open against an elastic steel spring acting on the ball to enlarge the flow rate in the flow path 7.

REFERENCE NUMERALS

(18) Ref. No. Description 1 Machine arrangement 2 Crankshaft 3 Roller bearing 4 Bearing ring (outer ring) 5 Bearing ring (inner ring) 6 Roller elements 7 Device for delivering of a lubricant 7 Lubricant reservoir 7 Flow path 8 Rolling contact 9 Valve element 10 Restriction element (ball) 11 Spring element 12 Seat 13 Valve housing 14 Filter element 15 First bore 16 Second bore 17 Mounting plane F Spring force