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] The invention relates to a balancing mechanism for a positive displacement machine based on the spiral principle, in particular for a scroll compressor, and to a positive displacement machine based on the spiral principle with such a balancing mechanism. A balancing mechanism according to the preamble of claim 1 is known, for example, from DE 33 38 737 A1.

[0002] Scroll compressors incorporating a compensation mechanism are known from the prior art, for example, from DE 10 2020 121 442 A1, which originates from the applicant. This compensation mechanism serves to compensate for manufacturing tolerances and thus ensure that two nested displacement spirals seal tightly against each other. It also reduces existing vibrations, oscillations, and noise.

[0003] From the aforementioned DE 33 38 737 A1, a balancing mechanism for a compressor based on the spiral principle is known. The balancing mechanism has a counterweight with a wedge that engages in a keyway. For this purpose, a disk is provided in which the keyway is formed and which is coupled to a crankshaft of the compressor.

[0004] Further scroll compressors with such compensation mechanisms are known, for example, from US 4,824,346 A, DE 10 2019 108 079 A1 and JP H04 321 785 A. Based on this prior art, the object of the invention is to further develop a compensation mechanism for a positive displacement machine based on the spiral 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 spiral principle, in particular a scroll compressor, with such a compensation mechanism.

[0005] Within the scope of the present invention, this problem is solved with regard to the compensation mechanism by the subject matter of claim 1 and with regard to the displacement machine by the subject matter of claim 15.

[0006] The invention is based on the concept of providing a balancing mechanism for a positive displacement machine based on the spiral principle, in particular a scroll compressor, wherein the balancing mechanism comprises a drive shaft with a central axis S and a balancing device. The balancing device has a cylindrical hub element rotatably mounted about an axis of rotation P and supported on a first eccentric journal of the drive shaft. Furthermore, the balancing device has a balancing element rotatably mounted about an axis of rotation J on the hub element and having an eccentrically arranged elongated hole extending radially with respect to the axis of rotation J. A second eccentric journal of the drive shaft is guided in the elongated hole of the balancing element such that a crank loop is formed between the elongated hole and the axis of rotation J of the balancing element.

[0007] The invention preferably utilizes a single compensating element to reduce vibrations and thus contribute to the smooth running of a positive displacement machine. The elongated hole of the compensating element ensures that its movement in the radial direction relative to the central axis S of the drive shaft is limited. Together with the second eccentric pin, the elongated hole defines a direction of movement for the compensating element, essentially forming a crank loop. This results in a combined oscillating and linear motion. It has been found that this crank loop movement is particularly effective at compensating for manufacturing tolerances and thus ensures a highly effective seal between two displacer spirals. Simultaneously, the compensating mechanism according to the invention reduces vibrations within a positive displacement machine.

[0008] In a preferred embodiment of the invention, the center of gravity of the compensating element exhibits 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 central axis Q of the elongated hole. The center of gravity of the compensating element can, in particular, be arranged radially outside the central axis Q of the elongated hole with respect to the central axis S of the drive shaft. In this position, the crank loop of the compensating element ensures that the center of gravity of the compensating element exhibits a pendulum component and efficiently utilizes this to compensate for manufacturing tolerances in the circumferential direction of the drive shaft.

[0009] The center of gravity of the compensating element can additionally exhibit a linear component during operation, whereby the center of gravity moves along the connecting line JQ and the linear component is greater than the oscillatory component. The linear component is primarily determined by the elongated hole, which restricts any rotational or oscillatory movement of the compensating element. The linear component of the movement of the center of gravity of the compensating element, which is preferably oriented radially with respect to the central axis of the drive shaft, is particularly advantageous for damping vibrations and sealing between displacement spirals.

[0010] The compensating element has a rotational axis J, and the hub element comprises a central axis C. In a particularly preferred embodiment 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 coincident. 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.

[0011] The hub element can further feature an eccentric hub bore in which the first eccentric pin of the drive shaft is arranged. Overall, the compensating mechanism advantageously exhibits multiple eccentricities in order to achieve, through the resulting movement sequence, a good seal between the displacer spirals and a reduction in noise during the operation of a displacer machine.

[0012] In a further embodiment of the invention, the compensating element has a receiving bore through which it is rotatably mounted on the hub element. In this way, the movement sequence advantageous for vibration reduction is transmitted from the drive shaft to the movable displacer spiral, with the receiving bore forming one of several pivot joints for the movement sequence.

[0013] The compensating element itself can comprise 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 results in particularly good mass balancing in every operating state of the compensating mechanism. Vibration reduction is thus achieved especially effectively.

[0014] The receiving bore and the slot are preferably arranged in the guide section. The guide section thus creates a connection between the axis of rotation of the compensating element and the compensating mass, which is positioned as far radially outside the axis of rotation of the compensating element as possible in order to be as small as possible due to leverage. At the same time, the distance between the axis of rotation of the compensating element and the compensating mass is kept so short that the compensating mechanism can be compactly integrated into a 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-ring shape around the axis of rotation J of the balancing element.

[0016] Particularly preferred, especially for reasons of stability, is the formation of the guide section and the compensating mass as a single piece, particularly monolithically. Overall, the compensating element can be designed as a single-piece or monolithic component.

[0017] Another embodiment 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 may have a greater length than the second eccentric pin of the drive shaft. Furthermore, the hub element may project along its central axis C beyond the compensating element, in particular the compensating mass. 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 thus projects beyond the compensating element in order to transmit a rotary motion to the first displacement spiral.

[0018] To ensure the smoothest possible running of the hub element around the first eccentric pin, the hub element can be 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 based on the spiral principle, in particular a scroll compressor, with a previously described compensating mechanism. In the positive displacement machine according to the invention, the hub element can be provided with a scroll bearing connected to a movable, in particular orbiting, displacer spiral, wherein the movable displacer spiral engages with a stationary displacer spiral.

[0019] The invention is explained in more detail below with reference to exemplary embodiments and the accompanying schematic drawings. These show Fig. 1 a cross-sectional view of a displacement machine according to the invention based on the spiral principle with a compensating mechanism according to a preferred embodiment, wherein the hub element is in contact with a movable displacement spiral via a sliding bearing; Fig. 2 a cross-sectional view of a displacement machine according to the invention based on the spiral principle with a compensating mechanism according to a further embodiment, wherein the hub element is connected to the movable displacement spiral via a ball bearing; Fig. 3 an exploded view of a compensating mechanism according to the invention based on a preferred embodiment; Fig. 4 a perspective view of the compensating mechanism according to Fig. 3in the assembled state; and Fig. 5 a top view of the balancing mechanism according to Fig. 3

[0020] In the Figs. 1 and 2 Each of the following is a positive displacement machine based on the spiral principle, which is largely identical in construction. The exemplary embodiments according to Figs. 1 and 2 They differ only in the type of scroll bearing 32, which is arranged between a hub element 30 and a movable displacement spiral 4. Whereas in the embodiment according to Fig. 1 where a sliding bearing 32a is provided as a scroll bearing 32, the embodiment according to Fig. 2 a 32b ball bearing as a 32 scroll bearing.

[0021] In general, the displacement machine comprises according to Figs. 1 and 2Each compressor housing 1 has an electronics housing 2 connected to it. An electric motor 3 is positioned inside the compressor housing 1, driving a drive shaft 10. The drive shaft 10 acts via an eccentric mechanism on a movable displacement spiral 4, which performs an orbiting motion during operation. The movable displacement spiral 4 engages with a stationary displacement spiral 5, and the engagement and the orbiting motion create variable compression chambers between the spiral walls of the displacement spirals 4 and 5.

[0022] The eccentric mechanism between the drive shaft 10 and the movable displacement spiral 4 is designed as part of a balancing mechanism, which will be described in more detail below. Figs. 3 to 5 is described.

[0023] The compensating mechanism comprises the drive shaft 10 and a compensating device 20. The compensating device 20 essentially connects the drive shaft 10 to the movable displacer spiral 4.

[0024] The compensating device 20 is designed in multiple parts and comprises, in particular, a hub element 30 and a compensating 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 provided between the first eccentric pin 11 and the hub bore 31.

[0025] 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 displacer spiral 4 and preferably carries the scroll bearing 32. The scroll segment 35 and the receiving segment 34 each have a cylindrical outer contour, with the receiving segment 34 having a smaller cross-sectional diameter than the scroll segment 35.

[0026] The receiving segment 34 accommodates 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 its projecting section for receiving a retaining ring 33. In this way, the compensating element 40 is secured longitudinally on the hub element 30.

[0027] In general, the compensating element 40 is rotatably mounted on the hub element 30. The receiving segment 34 can thus form a sliding bearing for the receiving bore 41 of the compensating element 40. By rotatably mounting the compensating element 40 on the hub element 30, the compensating device 20 achieves a decoupling of the eccentric connection between the first eccentric pin 11 and the movable displacement spiral 4 from the compensating mass 44. This results in a particularly good seal between the displacement spirals 4 and 5. The variable compression chambers are therefore well sealed. At the same time, the decoupling of the compensating mass 44 ensures smooth running.

[0028] The compensating element 40 comprises a guide section 43 which carries the receiving bore 41. Furthermore, a compensating mass 44 is provided, which extends substantially in a semi-circular or arc-shaped manner around the guide section 43. In particular, the compensating mass 44 can extend in an arc-shaped manner around the receiving bore 41. The compensating mass 44 preferably has a greater depth than the guide section 43.

[0029] Furthermore, a slot 42 is arranged in the guide section 43, extending through the guide section 43 and whose longer transverse axis is oriented substantially radially to the axis of rotation J of the compensating element. The slot 42 accommodates a second eccentric pin 12 of the drive shaft 10, the width of the slot 42 along its shorter transverse axis being substantially equal to the diameter of the second eccentric pin 12. The length of the slot 42, measured along its longer transverse axis, is correspondingly greater than the diameter of the second eccentric pin 12.

[0030] As in the assembled state of the compensating device 20 according to Fig. 4As shown, the first eccentric pin 11 engages in the hub bore 31 and the second eccentric pin 12 engages in the elongated hole 42. The first eccentric pin 11 extends beyond the compensating element 40, but ends within the hub bore 31. The second eccentric pin 12 ends within the elongated hole 42, i.e., it does not extend beyond the elongated hole 42.

[0031] Fig. 5 Figure 1 shows a front view of the compensating device 20, illustrating the position of the different axes that are crucial for the movement of the compensating mechanism. The drive shaft 10 has a central axis S, which essentially forms the axis of rotation of the drive shaft 10.

[0032] The hub element 30 has a central axis C that extends through the center of the hub element 30. The hub bore 31 of the hub element 30 is eccentrically formed within the hub element 30. A central axis of the hub bore 31 forms the axis of rotation P of the hub element 30. The hub element 30 therefore rotates about the axis of rotation P, which is defined by the central axis of the hub bore 31 or the central axis of the first eccentric pin 11.

[0033] The compensating element 40 rotates about an axis of rotation J, which is defined by the central axis of the receiving bore 41. In the present embodiment, the axis of rotation J of the compensating element 40 coincides with the central axis C of the hub element 30. However, it is also possible that the receiving bore 41 is oriented eccentrically to the central axis C of the hub element, so that the axis of rotation J of the compensating element 40 is located 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.

[0034] The elongated hole 42 has a central axis Q that extends in the bore direction of the elongated hole 42, i.e., 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 of the two transverse axes of the elongated hole 42.

[0035] The compensating element 40 further has a center of gravity 45, which is 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 to be understood in relation to the axis of rotation J of the compensating element 40.

[0036] Between the axis of rotation P of the hub element 30, the axis of rotation J of the compensating element 40, and the central axis Q of the elongated hole 42, a crank loop is formed during operation. This loop causes the center of gravity 45 to undergo a movement during operation of the compensating device 20. This movement has a linear component extending radially along the line connecting the axis of rotation JQ of the compensating element 40 and the central axis Q of the elongated hole 42, and a pendulum component oriented essentially circumferentially around the axis of rotation J of the compensating element 40. The linear component of the center of gravity 45's movement is greater than the circumferential and pendulum components. This type of movement, particularly the linear component, significantly reduces vibrations within a positive displacement machine and also reduces noise.

Claims

1. A compensation mechanism for a positive displacement machine based on the spiral principle, in particular, scroll compressor, wherein the compensation mechanism comprises a drive shaft (10) with a central axis (S) and a compensating device (20) which comprises - a cylindrical hub element (30) that is supported on a first eccentric pin (11) of the drive shaft (10) so that it can rotate about a rotational axis (P), and - a compensating element (40) that is supported on the hub element (30) so that it can rotate about a rotational axis (J), characterized in that the compensating element (40) comprises an eccentrically arranged oblong hole (42) which extends in a radial direction with respect to the rotational axis (J), wherein a second eccentric pin (12) of the drive shaft (10) is guided in the oblong hole (42) of the compensating element (40) in such a way that a sliding crank is formed between the oblong hole (42) and the rotational axis (J) of the compensating element (40).

2. The compensation mechanism according to Claim 1, characterized in that a centre of gravity (45) of the compensating element (40) has a pendulum component in operation, wherein the centre of gravity (45) oscillates around a connecting line (JQ) between the rotational axis (J) of the compensating element (40) and a central axis (Q) of the oblong hole (42).

3. The compensation mechanism according to Claim 2, characterized in that the centre of gravity (45) of the compensating element (40) has a linear portion in operation, wherein the centre of gravity (45) moves along the connecting line (JQ), and wherein the linear portion is greater than the pendulum portion.

4. The compensation mechanism according to any one of the preceding claims, characterized in that the rotational axis (J) of the compensating element (40) is arranged concentrically to a central axis (C) of the hub element (30).

5. The compensation mechanism according to any one of the preceding claims, characterized in that the rotational axis (J) of the compensating element (40) is eccentrically arranged to a central axis (C) of the hub element (30).

6. The compensation mechanism according to any one of the preceding claims, characterized in that the hub element (30) comprises an eccentric hub bore hole (31) in which the first eccentric pin (11) of the drive shaft (10) is arranged.

7. The compensation mechanism according to any one of the preceding claims, characterized in that the compensating element (40) comprises a mounting hole (41), via which the compensating element (40) is rotatable on the hub element (30).

8. The compensation mechanism according to any one of the preceding claims; characterized in that the compensating element (40) comprises a guide section (43) and a compensating mass (44), wherein the compensating mass (44) extends in an arc shape around the guide section (43).

9. The compensation mechanism according to Claim 8, characterized in that the mounting hole (41) and the oblong hole (42) are located in the guide section (43).

10. The compensation mechanism according to Claim 8 or 9, characterized in that the compensating mass (44) extends in a semi-ring shape around the rotational axis (J) of the compensating element (40).

11. The compensation mechanism according to any one of the Claims 8 to 10, characterized in that the guide section (43) and the compensating mass (44) are a single piece, in particular, monolithic.

12. The compensation mechanism according to any one of the preceding claims; characterized in that the first eccentric pin (11) of the drive shaft (10) has a larger diameter and / or length than the second eccentric pin (12) of the drive shaft (10).

13. The compensation mechanism according to any one of the preceding claims, characterized in that the hub element (30) protrudes along its central axis (C) over the compensating element (40), in particular, the compensating mass (44).

14. The compensation mechanism according to any one of the preceding claims, characterized in that the hub element (30) is mounted on the first eccentric pivot (11) of the drive shaft (10) in a rotatable manner by means of a plain or needle bearing and / or that the compensating element (40) is rotatable on the hub element (30) by means of a plain or needle bearing.

15. A spiral positive displacement machine, in particular, a scroll compressor, with a compensation mechanism according to any one of the preceding claims.

16. The positive displacement machine according to Claim 15, characterized in that the hub element (30) carries a scroll bearing which is connected to a movable displacement spiral, which orbits, in particular, during operation, wherein the moveable displacement spiral engages with a stationary displacement spiral.

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