EP-4737723-A1 - LINEAR COMPRESSOR, COOLING SYSTEM, AND HOUSEHOLD APPLIANCE

Abstract

Disclosed is a linear compressor 100, 100' comprising a cylinder component 3, 3' and a piston 5 extending into an inner space of the cylinder component. The linear compressor 100, 100' further comprises a linear motor 1 configured to generate a reciprocation of the cylinder component 3 and the piston 5 relative to each other, and a spring system 4, 4', 4", 4‴ configured to elastically cushion said reciprocation. Therein, a stiffness of the spring system 4, 4', 4", 4‴ depends on a deflection thereof. Further disclosed are a cooling system and a household appliance respectively comprising such linear compressor 100, 100'.

Inventors

• ORAVEC, Matej
• Kovac, Daniel
• Roetzer, Marco

Assignees

• BSH Hausgeräte GmbH
• Robert Bosch GmbH

Dates

Publication Date

20260506

Application Date

20241104

Claims (7)

1. Linear compressor (100, 100') comprising - a piston (5), - a cylinder component (3, 3') whose cylinder wall (3 w ) at least partially encompasses the piston (5'), - a linear motor (1) configured to generate a reciprocation of the cylinder component (3) and the piston (5) relative to each other, and - a spring system (4, 4', 4", 4‴) configured to elastically cushion said reciprocation, characterised in that a stiffness of the spring system (4, 4', 4", 4‴) depends on a deflection thereof.
2. Linear compressor according to claim 1, wherein the spring system (4, 4', 4", 4‴) comprises - a first spring (4a', 4a"), and a second spring (4b', 4b") which is configured to be deflected, in the linear compressor, only when the first spring (4a', 4a") exceeds a predetermined deflection; and/or - at least one non-linear spring (4a, 4a‴).
3. Linear compressor according to one of claims 1 or 2, wherein the spring system (4, 4', 4", 4‴) has a progressive spring characteristic.
4. Linear compressor according to claim 3, wherein the spring characteristic of the spring system (4', 4") is progressive with at least one knee.
5. Cooling system comprising a linear compressor (100, 100') according to one of the preceding claims.
6. Household appliance comprising a linear compressor (100, 100') according to one of claims 1 to 4.
7. Household appliance according to claim 6, which is a refrigerator, a freezer, or an air conditioner.

Description

The present invention concerns a linear compressor. The invention further is directed to a cooling system and a household appliance respectively comprising such linear compressor. According to conventional construction, a linear compressor typically comprises a piston and a cylinder component which together enclose a compression space at a bottom of the cylinder component. A linear motor is configured to linearly reciprocate the piston and the cylinder component relative to each other in a direction of a centre axis of the cylinder component and, thereby varying a volume of the compression space. Such linear compressor may in particular be included in a cooling system. Typically, the linear compressor is powered by synchronous input voltage, i.e., by an alternating current whose maximum and minimum have the same absolute value. Such driven, the movement of the piston relative to the cylinder component is synchronous, too. In applications in which the compressor forms part of a cooling system, such symmetric mode is commonly used for lower cooling capacity, and it ensures a quite stable state of the whole cooling circuit. To boost the mass flow rate of the linear compressor (such as, in respective applications, in order to increase a cooling power thereof), the alternating current driving the linear motor is conventionally supplemented by a direct current. Thereby, an asymmetric current is generated which causes an offset in the movement of the piston and the cylinder component relative to each other, meaning that maximum and minimum amplitudes thereof are different. Due to such asymmetric current, however, high power losses occur, such that the efficiency of the whole system is reduced. Moreover, to introduce the direct current and to control the resulting signals according to said conventional approach, a complex control system is required. It is an object of the present invention to provide an improved linear compressor, an improved cooling system, and an improved household appliance. The objects are achieved with a linear compressor according to claim 1, with a cooling system according to claim 5, and with a household appliance according to claim 6. Advantageous embodiments are disclosed in the dependent claims, the description, and the figures. A linear compressor according to the present invention comprises a piston and a cylinder component whose cylinder wall at least partially encompasses the piston. The linear compressor further comprises a linear motor which is configured to generate a reciprocation of the cylinder component and the piston relative to each other. As is to be understood, in operation of the linear compressor, such reciprocation causes a compression space formed between the piston and the cylinder component to alternatingly expand or diminish. The linear compressor further comprises a spring system which is configured elastically cushion said reciprocation. Therein, the spring system has a stiffness (thus, a resistance to load) which depends on a deflection of the spring system. In particular, such varying stiffness may be achieved by the spring system comprising, for example, at least one non-linear spring and/or two (or more) springs a second one of which comes into effect (i.e., is deflected) only after a first one of the springs exceeds a predetermined deflection. The spring system's stiffness thus depends on a position of the cylinder component and the piston relative to each other. Accordingly, an offset of the movement of the piston and the cylinder component relative to each other can be generated mechanically, even with a synchronous alternating input voltage. As a consequence, by varying an input power, an asymmetry in the reciprocation can be generated, without introducing a direct current and, thereby, without causing a loss of efficiency and without needing a complex control system. According to advantageous embodiments, the linear compressor is included or configured to be included in a cooling system. A cooling system according to the present invention comprises a linear compressor according to an embodiment of the present invention. In these cases, the linear compressor may in particular be configured to compress a refrigerant within its compression space. In particular, the cooling system may form part of a refrigerator, a freezer, or an air conditioner. A household appliance according to the present invention comprises a linear compressor according to an embodiment of the present invention. In particular, the household appliance may comprise a cooling system according to the present invention. As specific examples, the household appliance may be a refrigerator, a freezer, or an air conditioner. The spring system according to the present invention may comprise one or various tension spring/s and or one or various compression spring/s. It may in particular support the cylinder component and/or the piston against each other and/or (directly and/or via some further comp