MIXING VALVE ARRANGEMENT FOR A HYDRAULIC SYSTEM, INCLUDING AN OIL COOLING SYSTEM AND COMPRESSOR SYSTEM

Abstract

A mixing valve arrangement for a hydraulic system is provided with a medium cavity, in which a mixing cylinder, a first and a second inlet chamber as well as an outlet are provided. A mixing piston is axially mounted and movable in the mixing cylinder, provided with a flow path with an inlet opening, a variable cross-section of said inlet opening culminating into the first and/or the second inlet chamber, according to the axial position of the mixing piston, and with an outlet opening culminating in the outlet of the mixing cylinder. A thrust rod is axially mounted and movable and connected to the mixing piston, to change the axial position thereof. A drive is connected as an actuator to the thrust rod, for the axial movement of the same. The drive is an electrical motor, which is completely arranged inside the medium cavity.

Claims

1. A mixing valve arrangement (01) for a hydraulic system, the mixing valve arrangement comprising: a medium cavity (03), in which a mixing cylinder (04), at least one first and a second inlet chamber (08) as well as an outlet (13) are provided, said inlet chambers (08) being axially offset and each connected to an assigned medium supply channel (09), and culminating in the mixing cylinder (04), whereby via the medium supply channels (09) at least two medium components are supplied for their mixing; a mixing piston (05), which is axially mounted and movable in the mixing cylinder (04), showing at least one flow path with at least one inlet opening (11), a variable cross-section of which, according to the axial position of the mixing piston (05) culminates in the first and/or the second inlet chamber (08), and with an outlet opening (12), culminating in the outlet (13) of the mixing cylinder (04); a thrust rod (18), which is axially mounted and movable and connected to the mixing piston (05), in order to change the axial position thereof; and a drive, said drive being connected as an actuator to the thrust rod (18), for the axial movement thereof; characterized in that the drive is an electrical motor (15), which is completely arranged inside the medium cavity (03).

2. The mixing valve arrangement (01) according to claim 1, characterized in that the electrical motor (15) is a step motor with an axially movable drive rod (18), which is connected to the thrust rod or integrated with said thrust rod.

3. The mixing valve arrangement (01) according to claim 1, characterized in that the electrical motor (15) is arranged pressure-open in the mixing cavity (03), in order to avoid any pressure differences along its axial extension, irrespective of the axial position of the mixing piston (05).

4. The mixing valve arrangement (01) according to claim 1, characterized in that the inlet chambers (08) are formed as annular cross-section expansions of the mixing cylinder (04).

5. The mixing valve arrangement (01) according to claim 1, characterized in that the mixing piston (05) is formed as a cylindrical sleeve, provided with several slot-shaped inlet openings (11) circumferentially distributed.

6. The mixing valve arrangement (01), according to claim 1, characterized in that the axial opposite ending of the mixing cylinder (05) is sealed

7. The mixing valve arrangement according to claim 6, characterized in that one pressure equalization channel (22) passes from the mixing cylinder (04) into the closing plate (16), in order to provide a pressure equalization on all sides of the electrical motor (15).

8. The mixing valve arrangement (01) according to claim 1, characterized in that said valve arrangement is configured in an oil circuit for the temperature control, whereby oil is supplied via the first inlet chamber (08a) at a first temperature and via the second inlet chamber (08b) at a second temperature, and whereby a temperature sensor is provided for the recording of the medium temperature at least at the outlet (13) of the mixing cylinder (04).

9. An oil cooling system with a closed oil circuit, a cooler for the cooling of the circulated oil, with a heating source for the supply of the cooled oil at a pre-set inlet temperature, and with a temperature control unit for the setting of the pre-set inlet temperature, characterized in that said temperature control unit comprises a mixing valve arrangement (01) according to claim 1.

10. A compressor system with an oil-injected compressor unit for the generation of pressurized air and with an oil cooling system according to claim 9.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Further advantages and singularities of the invention are provided by the following description of a preferred embodiment in accordance with the drawing.

[0022] The single FIGURE shows a section view of a section of an inventive mixing valve arrangement.

DETAILED DESCRIPTION

[0023] Before any embodiments of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure is capable of supporting other embodiments and of being practiced or of being carried out in various ways.

[0024] The mixing valve arrangement 01 has a housing 02, said housing being an integrated part of a hydraulic system, e.g. an oil cooling system. Within the housing 02, a medium cavity 03 is formed, in which a medium is passed during operation. A section of the medium cavity 03 forms a mixing cylinder 04, in which a mixing piston 05 is arranged, said mixing piston movable in axial direction. A coil spring 07 has an axial effect on the mixing piston 05 and presses it into a zero condition.

[0025] The wall sections of a mixing cylinder 04 are adjacent to a first inlet chamber 08a and a second inlet chamber 08b. The inlet chambers 08 extend as annular sections around the mixing cylinder 04 and are opened inside them, provided this opening is not closed by the wall of the mixing piston 05. The inlet chambers are connected respectively to a medium supply channel 09a, 09b, along which the medium components are supplied for their mixing. The mixing cylinder 04 has several inlet openings 11 in its wall, said inlet openings being formed as slots oriented at the circumference. Should due to the appropriate axial positioning of the mixing piston, the inlet openings 11 be in any case congruent with the inlet chambers 08, the corresponding medium component passes inside the medium piston. The flow path then runs through an outlet opening 12 located at the end face of the mixing piston 05 to an outlet 13 of the mixing cylinder 04.

[0026] The mixing valve arrangement further comprises an electrical motor 15, said electrical motor preferably being a step motor and operating as and adjusting drive for the mixing piston 05. The electrical motor is fitted to a closing plate 16, said closing plate sealing tightly the medium cavity 03 at the end of the mixing cylinder 04. The complete motor is so arranged inside the medium cavity, meaning that equal pressure ratios are available on all sides.

[0027] In the illustrated embodiment, the electrical motor section averted from the closing plate 16 partially intrudes into an integrated section 17 of the mixing piston 05. The electrical motor 15 is connected as an actuator to the mixing piston 05 via an axially movable drive rod 18. The drive rod 18 functions as a thrust rod, which by the actuation of the electrical motor, performs an axial movement of the mixing piston 05 in the mixing cylinder 04. At the ending on the piston side, the drive rod 18 is mounted e.g. on an intermediate plate 19 of the mixing piston 05. The intermediate plate is preferably provided with openings (not shown), so that equal pressure ratios are available at both sides of the intermediate plate 19. At the opposite axial side, the drive rod 18 is directed out of the motor housing with one pressure ending 21, said pressure ending 21 being located in the medium cavity 03 and subject to the same pressure as the mixing piston 05. If other constructive measures are not already sufficient for the manufacturing of a pressure-open connection, a separate pressure equalization channel 22 is provided, connecting the mixing cylinder 04 to the rear side of the electrical motor and the open pressure ending 21 of the drive rod 18.

REFERENCE SIGN LIST

[0028] 1 Mixing valve arrangement [0029] 2 Housing [0030] 3 medium cavity [0031] 4 Mixing cylinder [0032] 5 Mixing piston [0033] 6 [0034] 7 Coil spring [0035] 8 Inlet chambers [0036] 9 Medium supply channels [0037] 10 [0038] 11 Inlet opening [0039] 12 Outlet opening [0040] 13 Outlet [0041] 14 [0042] 15 Electrical motor [0043] 16 Closing plate [0044] 17 Integrated section [0045] 18 Drive rod/Thrust rod [0046] 19 Intermediate plate [0047] 20 [0048] 21 Pressure ending [0049] 21 Pressure equalization channel

[0050] Various features and advantages of the disclosure are set forth in the following claims.