Compensation mechanism for a displacement machine

Abstract

The invention relates to a compensation mechanism for a displacement machine according to the spiral principle, in particular a scroll compressor, wherein the compensation mechanism comprises a driveshaft (10) with a central axis S and a compensation device (20), which comprises a cylindrical hub element (30) that is mounted on a first eccentric pin (11) of the driveshaft (10) such that it can rotate about an axis of rotation P, and a compensation element (40) which is mounted on the hub element (30) such that it can rotate about an axis of rotation J and which has an eccentrically arranged slotted hole (42) extending in the radial direction relative to the axis of rotation J, wherein a second eccentric pin (12) of the driveshaft (10) is guided in the slotted hole (42) of the compensation element (40) such that a Scotch yoke is formed between the slotted hole (42) and the axis of rotation J of the compensation element (40). The invention also relates to a displacement machine comprising a compensation mechanism of this type.

Description

[0001] Compensation mechanism for a displacement machine

[0002] Description

[0003] The invention relates to a balancing mechanism for a positive displacement machine according to the spiral principle, in particular for a scroll compressor, and to a positive displacement machine according to the spiral principle with such a balancing mechanism.

[0004] Scroll compressors that include a balancing mechanism are known from the prior art, for example, DE 10 2020 121 442 A1, which is attributed to the applicant. The balancing mechanism serves to compensate for manufacturing tolerances and thus ensures that two nested displacement scrolls fit tightly together. Furthermore, existing oscillations, vibrations, and noise are reduced.

[0005] Other scroll compressors with such balancing mechanisms are known, for example, from US 4,824,346 A and DE 10 2019 108 079 Al.

[0006] Based on this prior art, the object of the invention is to further develop a balancing mechanism for a positive displacement machine based on the scroll principle, in particular a scroll compressor, in order to achieve improved vibration reduction with low component complexity. A further object of the invention is to provide a positive displacement machine based on the scroll principle, in particular a scroll compressor, with such a balancing mechanism.

[0007] Within the scope of the present invention, this object is achieved with regard to the compensation mechanism by the subject matter of patent claim 1 and with regard to the displacement machine by the subject matter of patent claim 15.

[0008] The invention is based on the idea of ​​specifying a balancing mechanism for a positive displacement machine according to the spiral principle, in particular a scroll compressor, wherein the balancing mechanism has a drive shaft with a central axis S and a balancing device. The balancing device has a cylindrical hub element which is rotatable about an axis of rotation P and is mounted on a first eccentric pin of the drive shaft. Furthermore, the balancing device has a balancing element which is mounted on the hub element so as to be rotatable about an axis of rotation J and has an eccentrically arranged elongated hole which extends in the radial direction with respect to the axis of rotation J. A second eccentric pin of the drive shaft is guided in the elongated hole of the balancing element such that a crank slider is formed between the elongated hole and the axis of rotation J of the balancing element.

[0009] The invention preferably uses a single compensating element to reduce vibrations and thus contribute to the smooth running of a positive displacement machine. The elongated hole in the compensating element ensures that movement of the compensating element in the radial direction relative to the center axis S of the drive shaft is limited. The elongated hole, together with the second eccentric pin, thus specifies a direction of movement for the compensating element, which essentially forms a crank slider. Essentially, a combined oscillating and linear movement occurs. It has been found that this movement in the form of a crank slider compensates for manufacturing tolerances particularly well and thus ensures a highly effective seal between two displacement spirals. At the same time, the compensating mechanism according to the invention reduces vibrations within a positive displacement machine.

[0010] In a preferred embodiment of the invention, a center of gravity of the compensating element has a pendulum component during operation, wherein the center of gravity oscillates about a connecting line JQ between the axis of rotation J of the compensating element and a center axis Q of the elongated hole. The center of gravity of the compensating element can be arranged radially outside the center axis Q of the elongated hole, in particular with respect to the center axis S of the drive shaft. In this position, the crank slider of the compensating element ensures that the center of gravity of the compensating element has a pendulum component and uses this efficiently to compensate for manufacturing tolerances in the circumferential direction of the drive shaft. The center of gravity of the compensating element can additionally have a linear component during operation, wherein the center of gravity moves along the connecting line JQ and wherein the linear component is greater than the pendulum component.The linear component is primarily determined by the elongated hole, which restricts any rotational or pendulum movement of the compensating element. The linear component of the movement of the compensating element's center of gravity, which is preferably aligned radially relative to the center axis of the drive shaft, is particularly advantageous for damping vibrations and sealing between displacement spirals.

[0011] The compensating element has the rotational axis J, and the hub element comprises a central axis C. In a particularly preferred variant of the invention, the rotational axis J of the compensating element is arranged concentrically with a central axis C of the hub element. In other words, the rotational axis J of the compensating element and the central axis C of the hub element can be congruent. This design reduces the complexity of the compensating mechanism and limits the degrees of freedom of movement of the compensating mechanism to a level suitable for reducing vibrations.

[0012] The hub element can further have an eccentric hub bore in which the first eccentric pin of the drive shaft is arranged. Overall, the compensation mechanism advantageously has multiple eccentricities in order to achieve a good seal between the displacement spirals and reduce noise during operation of a positive displacement machine through the resulting movement sequence.

[0013] In a further variant of the invention, the compensating element has a receiving bore, via which the compensating element is rotatably mounted on the hub element. In this way, the movement sequence, which is advantageous for reducing vibration, is transmitted from the drive shaft to the movable displacement spiral, with the receiving bore forming one of several pivot joints for the movement sequence. The compensating element itself can have a guide section and a compensating mass. The compensating mass preferably extends in an arc around the guide section. It has been shown that such a design of the compensating element leads to particularly good mass balance in every operating state of the compensating mechanism. The vibration reduction is thus achieved particularly well.

[0014] The receiving bore and the elongated hole are preferably arranged in the guide section. The guide section thus creates a connection between the rotational axis of the compensating element and the compensating mass, which is arranged as far radially outside the rotational axis of the compensating element as possible in order to be designed as small as possible due to the leverage effect. At the same time, the distance between the rotational axis of the compensating element and the compensating mass is kept so short that the compensating mechanism can be compactly integrated into a positive displacement machine.

[0015] A particularly preferred embodiment of the invention also contributes to the compactness of the balancing mechanism, in which the balancing mass extends in a semi-circular manner around the axis of rotation J of the balancing element.

[0016] It is particularly preferred, particularly for stability reasons, if the guide section and the compensating mass are formed as a single piece, in particular monolithic. Overall, the compensating element can be formed as a single-piece component or a monolithic component.

[0017] A further variant of the invention provides that the first eccentric pin of the drive shaft has a larger diameter than the second eccentric pin of the drive shaft. Alternatively or additionally, the first eccentric pin of the drive shaft can be longer than the second eccentric pin of the drive shaft. Furthermore, the hub element can protrude beyond the compensating element, in particular the compensating mass, along its central axis C. The first and second eccentric pins of the drive shaft transmit different forces and are therefore preferably dimensioned differently. This serves to optimize weight. The hub element, on the other hand, preferably extends into an orbiting displacement spiral and therefore projects beyond the compensating element in order to be able to transmit a rotary movement to the first displacement spiral.

[0018] In order to ensure the smoothest possible running of the hub element around the first eccentric pin, it can be provided that the hub element is rotatably mounted on the first eccentric pin of the drive shaft via a plain or needle bearing. Alternatively or additionally, the compensating element can be rotatably mounted on the hub element via a plain or needle bearing. A secondary aspect of the invention relates to a positive displacement machine according to the spiral principle, in particular a scroll compressor, with a compensation mechanism as described above. In the positive displacement machine according to the invention, it can be provided that the hub element carries a scroll bearing which is connected to a movable, in particular orbiting, displacement spiral, wherein the movable displacement spiral engages with a stationary displacement spiral.

[0019] The invention will be explained in more detail below using exemplary embodiments with reference to the attached schematic drawings.

[0020] Fig. 1 is a cross-sectional view of a displacement machine according to the invention based on the spiral principle with a balancing mechanism according to a preferred embodiment, wherein the hub element is in contact with a movable displacement spiral via a plain bearing;

[0021] Fig. 2 is a cross-sectional view of a displacement machine according to the invention based on the spiral principle with a balancing mechanism according to a further embodiment, wherein the hub element is connected to the movable displacement spiral via a ball bearing;

[0022] Fig. 3 is an exploded view of a balancing mechanism according to the invention according to a preferred embodiment; Fig. 4 is a perspective view of the balancing mechanism according to Fig. 3 in the assembled state; and

[0023] Fig. 5 is a plan view of the balancing mechanism according to Fig. 3

[0024] Figs. 1 and 2 each show positive displacement machines based on the spiral principle, which are largely identical in design. The embodiments shown in Figs. 1 and 2 differ only in the type of scroll bearing 32, which is arranged between a hub element 30 and a movable displacement spiral 4. While the embodiment shown in Fig. 1 uses a plain bearing 32a as the scroll bearing 32, the embodiment shown in Fig. 2 includes a ball bearing 32b as the scroll bearing 32.

[0025] In general, the positive displacement machine according to Figs. 1 and 2 each comprises a compressor housing 1, to which an electronics housing 2 is connected. Positioned within the compressor housing 1 is an electric motor 3 that drives a drive shaft 10. The drive shaft 10 acts via an eccentric mechanism on a movable displacement spiral 4, which executes an orbiting motion during operation. The movable displacement spiral 4 engages with a stationary displacement spiral 5, whereby the engagement and the orbiting motion create variable compression chambers between the spiral walls of the displacement spirals 4, 5.

[0026] The eccentric mechanism between the drive shaft 10 and the movable displacement spiral 4 is designed as part of a balancing mechanism, which is described in more detail below with reference to Figs. 3 to 5.

[0027] The balancing mechanism comprises the drive shaft 10 and a balancing device 20. The balancing device 20 essentially connects the drive shaft 10 to the movable displacement spiral 4. The balancing device 20 is constructed in several parts and, in particular, comprises a hub element 30 and a balancing element 40. The hub element 30 is rotatably arranged on a first eccentric pin 11 of the drive shaft 10. For this purpose, the hub element 30 has a hub bore 31 into which the first eccentric pin 11 engages. A plain bearing or a needle bearing can be formed between the first eccentric pin 11 and the hub bore 31. The hub element 30 comprises a receiving segment 34 and a scroll segment 35. The receiving segment 34 faces the drive shaft 10, whereas the scroll segment 35 faces the movable displacement spiral 4 and preferably carries the scroll bearing 32.The scroll segment 35 and the receiving segment 34 each have a cylindrical outer contour, wherein the receiving segment 34 has a smaller cross-sectional diameter than the scroll segment 35.

[0028] The receiving segment 34 receives the compensating element 40. Specifically, the compensating element 40 has a receiving bore 41 through which the scroll segment 35 extends. The scroll segment 35 extends beyond the receiving bore 41 in the direction of the drive shaft 10 and has an annular groove in the projecting portion for receiving a retaining ring 33. In this way, the compensating element 40 is secured longitudinally axially on the hub element 30.

[0029] Generally, the compensating element 40 is rotatably mounted on the hub element 30. The receiving segment 34 can thus form a plain bearing for the receiving bore 41 of the compensating element 40. By rotatably arranging the compensating element 40 on the hub element 30, the eccentric connection between the first eccentric pin 11 and the movable displacement spiral 4 is decoupled from the compensating mass 44 in the compensating device 20. This results in a particularly good seal between the displacement spirals 4, 5. The variable compression chambers are thus well sealed. At the same time, the decoupling of the compensating mass 44 achieves a high level of smoothness.

[0030] The compensating element 40 comprises a guide section 43 that supports the receiving bore 41. Furthermore, a compensating mass 44 is provided, which extends substantially in a semi-circular or arcuate manner around the guide section 43. In particular, the compensating mass 44 can extend in an arcuate manner around the receiving bore 41. The compensating mass 44 preferably has a greater depth than the guide section 43.

[0031] Furthermore, an elongated hole 42 is arranged in the guide section 43, which extends through the guide section 43 and whose longer transverse axis is aligned substantially radially with the rotational axis J of the compensating element. The elongated hole 42 accommodates a second eccentric pin 12 of the drive shaft 10, wherein a width of the elongated hole 42 along the shorter transverse axis of the elongated hole 42 substantially corresponds to the diameter of the second eccentric pin 12. The length of the elongated hole 42, measured along the longer transverse axis of the elongated hole 42, is correspondingly larger than the diameter of the second eccentric pin 12.

[0032] As shown in the assembled state of the compensating device 20 according to Fig. 4, the first eccentric pin 11 engages in the hub bore 31, and the second eccentric pin 12 engages in the elongated hole 42. Although the first eccentric pin 11 extends beyond the compensating element 40, it ends within the hub bore 31. The second eccentric pin 12 ends within the elongated hole 42, thus not extending beyond the elongated hole 42.

[0033] Fig. 5 shows a front view of the balancing device 20, showing the position of the various axes that are crucial for the movement of the balancing mechanism. The drive shaft 10 has a central axis S, which essentially forms the axis of rotation of the drive shaft 10.

[0034] The hub element 30 has a central axis C extending centrally through the hub element 30. The hub bore 31 of the hub element 30 is formed eccentrically in the hub element 30. A central axis of the hub bore 31 forms the rotation axis P of the hub element 30. The hub element 30 thus rotates about the rotation axis P, which is defined by the central axis of the hub bore 31 or the central axis of the first eccentric pin 11.

[0035] The compensating element 40 rotates about a rotation axis J, which is defined by the central axis of the receiving bore 41. In the present exemplary embodiment, the rotation axis J of the compensating element 40 coincides with the central axis C of the hub element 30. However, it is also possible for the receiving bore 41 to be aligned eccentrically to the central axis C of the hub element, so that the rotation axis J of the compensating element 40 is arranged outside the central axis C of the hub element 30. For example, the receiving segment 34 of the hub element 30 can be designed eccentrically. The elongated hole 42 has a central axis Q, which extends in the bore direction of the elongated hole 42, i.e. runs parallel to the central axis S of the drive shaft 10. The position of the central axis Q of the elongated hole 42 is defined by the intersection point of the two transverse axes of the elongated hole 42.

[0036] The compensating element 40 further has a center of gravity 45 located in the guide section 43. The center of gravity 45 is preferably located radially outside the elongated hole 42 or the central axis Q of the elongated hole 42, where "radially outside" is understood to mean the rotational axis J of the compensating element 40.

[0037] During operation, a crank loop forms between the axis of rotation P of the hub element 30, the axis of rotation J of the compensating element 40, and the center axis Q of the elongated hole 42. This ensures that the center of gravity 45 performs a movement during operation of the compensating device 20. This movement has, on the one hand, a linear component extending in the radial direction along the connecting line JQ between the axis of rotation of the compensating element 40 and the center axis Q of the elongated hole 42, and a pendulum component oriented essentially in the circumferential direction around the axis of rotation J of the compensating element 40. The linear component of the movement of the center of gravity 45 is greater than the circumferential component or pendulum component. This type of movement, in particular the linear component, brings about a significant reduction in vibrations within a positive displacement machine and a reduction in noise.

Claims

Claims Compensation mechanism for a positive displacement machine according to the spiral principle, in particular scroll compressor, wherein the compensation mechanism has a drive shaft (10) with a central axis S and a compensation device (20) which - a cylindrical hub element (30) which is rotatably mounted about an axis of rotation P on a first eccentric pin (11) of the drive shaft (10), and - comprising a compensating element (40) rotatably mounted on the hub element (30) about an axis of rotation J and having an eccentrically arranged elongated hole (42) extending radially with respect to the axis of rotation J, wherein a second eccentric pin (12) of the drive shaft (10) is guided in the elongated hole (42) of the compensating element (40) such that a crank loop is formed between the elongated hole (42) and the axis of rotation J of the compensating element (40). Compensating mechanism according to claim 1, characterized by the fact that a center of gravity (45) of the compensating element (40) exhibits a pendulum component during operation, wherein the center of gravity (45) oscillates about a connecting line JQ between the axis of rotation J of the compensating element (40) and a central axis Q of the elongated hole (42).Compensating mechanism according to claim 2, characterized by the fact that the center of gravity (45) of the compensating element (40) has a linear component during operation, wherein the center of gravity (45) moves along the connecting line JQ, and wherein the linear component is greater than the pendulum component. Compensating mechanism according to any of the preceding claims, characterized by the fact that the axis of rotation J of the compensating element (40) is concentric to a. central axis C of the hub element (30) is arranged.

5. Compensation mechanism according to one of the preceding claims, characterized by the fact that the axis of rotation J of the compensating element (40) is arranged eccentrically to a central axis C of the hub element (30).

6. Compensation mechanism according to one of the preceding claims, characterized by the fact that the hub element (30) has an eccentric hub bore (31) in which the first eccentric pin (11) of the drive shaft (10) is arranged.

7. Compensation mechanism according to one of the preceding claims, characterized by the fact that the compensating element (40) has a receiving bore (41) via which the compensating element (40) is rotatably mounted on the hub element (30).

8. Compensation mechanism according to one of the preceding claims, characterized by the fact that the compensating element (40) has a guide section (43) and a compensating mass (44), wherein the compensating mass (44) extends in an arc around the guide section (43).

9. Compensation mechanism according to claim 8, characterized by the fact that the receiving bore (41) and the elongated hole (42) are arranged in the guide section (43).

10. Compensation mechanism according to claim 8 or 9, characterized by the fact that the compensating mass (44) extends in a semi-ring shape around the axis of rotation J of the compensating element (40).

11. Compensation mechanism according to one of claims 8 to 10, dad u rch kenn zei ch net that The guide section (43) and the counterweight (44) are formed in one piece, in particular monolithically. A counterweight mechanism according to one of the preceding claims, characterized by the fact that the first eccentric pin (11) of the drive shaft (10) has a larger diameter and / or a greater length than the second eccentric pin (12) of the drive shaft (10). A counterweight mechanism according to one of the preceding claims, characterized by the fact that the hub element (30) projects along its central axis C beyond the counterweight element (40), in particular the counterweight (44). Compensating mechanism according to one of the preceding claims, characterized by the fact that the hub element (30) is rotatably mounted on the first eccentric pin (11) of the drive shaft (10) via a sliding or needle bearing and / or that the compensating element (40) is rotatably mounted on the hub element (30) via a sliding or needle bearing.A positive displacement machine based on the spiral principle, in particular a scroll compressor, with a balancing mechanism according to one of the preceding claims. A positive displacement machine according to claim 15, characterized in that the hub element (30) carries a scroll bearing which is connected to a movable, in particular orbiting during operation, displacer spiral, wherein the movable displacer spiral engages with a stationary displacer spiral.

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