Compensation mechanism for positive displacement machinery

Abstract

The present invention relates to a compensation mechanism for a positive displacement machine, in particular a scroll compressor, according to the spiral principle, comprising a drive shaft (10) with a central axis S and a compensation device (20), the latter comprising a cylindrical hub element (30) rotatably supported about a rotation axis P on a first eccentric pin (11) of the drive shaft (10) and a compensation element (40) rotatably supported about a rotation axis J on the hub element (30) and having an eccentrically arranged slot (42) extending radially relative to the rotation axis J, the second eccentric pin (12) of the drive shaft (10) being guided in the slot (42) of the compensation element (40) such that a Scotch yoke mechanism is formed between the slot (42) and the rotation axis J of the compensation element (40).Furthermore, the present invention relates to a positive displacement machine equipped with such a compensation mechanism.

Description

Technical Field

[0001] The present invention relates to a positive displacement machine based on the spiral principle, particularly a compensation mechanism for a scroll compressor, and a positive displacement machine based on the spiral principle provided with such a compensation mechanism.

Background Art

[0002] Scroll compressors having a compensation mechanism are known from the prior art, such as German Patent Application DE102020121442Al belonging to the applicant of the present application. The compensation mechanism serves to compensate for manufacturing tolerances and ensure that two nested push-out spirals adhere well to each other. Furthermore, existing rocking, vibration, and noise are reduced. Another scroll compressor provided with such a compensation mechanism is known, for example, from US Patent Application US4,824,346A and German Patent Application DE102019108079Al.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Starting from this prior art, the problem of the present invention is to improve a compensation mechanism for a positive displacement machine based on the spiral principle, particularly a scroll compressor, and achieve improved reduction of vibration with low component complexity. Another problem of the present invention is to provide a positive displacement machine based on the spiral principle, particularly a scroll compressor, provided with such a compensation mechanism.

Means for Solving the Problems

[0004] Within the framework of the present invention, the above problems are solved by the subject matter of claim 1 with respect to the compensation mechanism and by the subject matter of claim 15 with respect to the positive displacement machine.

[0005] Therefore, the present invention is based on the idea of ​​providing a compensation mechanism for positive displacement machines based on the spiral principle, particularly for scroll compressors, the compensation mechanism comprising a drive shaft having a central axis S and a compensation device. The compensation device has a cylindrical hub element rotatably supported on a first eccentric pin of the drive shaft about a rotation axis P. Furthermore, the compensation device has a compensation element rotatably supported on the hub element about a rotation axis J, and having an eccentrically positioned slot extending radially with respect to the rotation axis J. The second eccentric pin of the drive shaft is guided into the slot of the compensation element such that a Scotch yoke mechanism is formed between the slot and the rotation axis J of the compensation element.

[0006] The present invention preferably uses a single compensating element to achieve vibration reduction and contribute to the smooth operation of a positive displacement machine. The slots in the compensating element act to restrict the compensating element from moving radially with respect to the central axis S of the drive shaft. Thus, the slots, together with the second eccentric pin, specify the direction of movement of the compensating element, which substantially forms a Scotch yoke mechanism. Thus, a motion substantially combining vibration and linear motion occurs. Motion in the form of this Scotch yoke mechanism has been found to compensate for manufacturing tolerances particularly well and to very effectively ensure a tight seal between the two displacement spirals. The compensating mechanism according to the present invention simultaneously reduces vibrations within the positive displacement machine.

[0007] In a preferred embodiment of the present invention, the center of gravity of the compensating element has a pendulum component during operation, and this center of gravity reciprocates about a connecting line JQ between the rotation axis J of the compensating element and the central axis Q of the slot. The center of gravity of the compensating element can be positioned radially outward of the central axis Q of the slot with respect to the central axis S of the drive shaft. At this position, the Scotch yoke mechanism of the compensating element works to ensure that the center of gravity of the compensating element has a pendulum component, and that this pendulum component is efficiently utilized to compensate for circumferential manufacturing tolerances of the drive shaft.

[0008] The center of gravity of the compensation element may also have a linear component during operation, and the center of gravity moves along the connecting line JQ, in which case the linear component is greater than the pendulum component. The linear component is mainly specified by the slot, thereby limiting the rotational or oscillating motion of the compensation element. The linear component of the movement of the center of gravity of the compensation element is preferably radially aligned with respect to the central axis of the drive shaft, which is particularly advantageous for vibration damping and sealing between the displacement spirals.

[0009] The compensation element has a rotation axis J, and the hub element has a central axis C. In a particularly preferred modification of the present invention, the rotation axis J of the compensation element is concentric with the central axis C of the hub element. In other words, the rotation axis J of the compensation element and the central axis C of the hub element can coincide perfectly. This design reduces the complexity of the compensation mechanism and limits the degrees of freedom of motion of the compensation mechanism to a degree suitable for vibration reduction.

[0010] The hub element may further have an eccentric hub hole in which the first eccentric pin of the drive shaft is located. Overall, the compensation mechanism has multiple eccentricities, and the resulting motion sequence can achieve good sealing between the displacement spirals and noise reduction during the operation of the positive displacement machine.

[0011] In another modification of the present invention, the compensating element has a retaining hole through which the compensating element is rotatably supported on a hub element. In this way, a motion sequence favorable for vibration reduction is transmitted from the drive shaft to the movable displacement spiral, and the retaining hole forms one of a plurality of rotary couplings for the motion sequence.

[0012] The compensation element itself may have a guide section and a balance weight. Preferably, the balance weight extends in an arc around the guide section. Such a design of the compensation element has been shown to result in particularly good mass equilibrium under all operating conditions of the compensation mechanism. Thus, vibration reduction is achieved with particularly good results.

[0013] It is preferable that the retaining holes and slots are located in the guide section. Therefore, the guide section connects the rotation axis of the compensation element to the balance weight, and the balance weight is positioned as far as possible radially outward from the rotation axis of the compensation element so that it can be designed to be as small as possible due to the lever effect. At the same time, the distance between the rotation axis of the compensation element and the balance weight is kept as small as possible so that the compensation mechanism can be compactly incorporated into a positive displacement machine.

[0014] In order to contribute to the miniaturization of the compensation mechanism, in a particularly preferred embodiment of the present invention, the balance weight extends in a semi-ring shape around the rotation axis J of the compensation element.

[0015] It is particularly preferable, for reasons of stability, that the guide section and the balance weight be formed integrally, especially monolithically. Overall, the balance weight can be formed as an integrated or monolithic component.

[0016] In another modification of the present invention, 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 have a longer length than the second eccentric pin of the drive shaft. Furthermore, the hub element can protrude from the compensating element, particularly the balance weight, along its central axis C. The first and second eccentric pins of the drive shaft transmit different forces and are therefore preferably designed to have different dimensions. This contributes to weight optimization. In contrast, the hub element preferably extends to the revolving displacement spiral and therefore protrudes beyond the compensating element so that it can transmit rotational motion to the first displacement spiral.

[0017] To ensure that the hub element rotates as smoothly as possible around the first eccentric pin, the hub element may be rotatably supported on the first eccentric pin of the drive shaft via a sliding bearing or a needle bearing. Alternatively or additionally, a compensation element may be rotatably supported on the hub element via a sliding bearing or a needle bearing. A second aspect of the present invention relates to a positive displacement machine based on the spiral principle, in particular a scroll compressor, comprising the above-described compensation mechanism. In the positive displacement machine according to the present invention, the hub element carries a scroll bearing connected to a movable displacement spiral, in particular a displacement spiral that revolves during operation, and this movable displacement spiral may engage with a fixed displacement spiral.

[0018] The present invention will be described in more detail below with reference to the attached schematic drawings. [Brief explanation of the drawing]

[0019] [Figure 1] Figure 1 is a cross-sectional view of a positive displacement machine of the present invention based on the spiral principle, equipped with a compensation mechanism according to a preferred embodiment, in which the hub element is in contact with the movable displacement spiral via a sliding bearing. [Figure 2] Figure 2 is a cross-sectional view of a positive displacement machine of the present invention based on the spiral principle, which includes a compensation mechanism according to another embodiment, in which the hub element is in contact with the movable displacement spiral via a ball bearing. [Figure 3] Figure 3 is an exploded perspective view of the compensation mechanism of the present invention according to a preferred embodiment. [Figure 4] Figure 4 is a perspective view of the compensation mechanism shown in Figure 3 in its assembled state. [Figure 5] Figure 5 is a plan view of the compensation mechanism shown in Figure 3. [Modes for carrying out the invention]

[0020] Figures 1 and 2 each show a positive displacement machine based on the spiral principle, and they have substantially the same structure. The difference between the embodiments shown in FIGS. 1 and 2 is only in the form of the scroll bearing 32 arranged between the hub element 30 and the movable push-off spiral 4. In the embodiment according to FIG. 1, a sliding bearing 32a is provided as the scroll bearing 32, while the embodiment according to FIG. 2 includes a ball bearing 32b as the scroll bearing 32.

[0021] Generally, the positive displacement machines shown in FIGS. 1 and 2 each have a compressor housing 1, to which an electronic equipment housing 2 is connected. Inside the compressor housing 1, an electric motor 3 for driving the drive shaft 10 is arranged. The drive shaft 10 acts on a movable push-off spiral 4 that performs a revolution motion during operation via an eccentric mechanism. The movable push-off spiral 4 engages with a fixed push-off spiral 5, and this engagement and the revolution motion create a variable compression chamber between the spiral walls of the push-off spirals 4 and 5.

[0022] The eccentric mechanism between the drive shaft 10 and the movable push-off spiral 4 is designed as part of a compensation mechanism that will be described in detail below with reference to FIGS. 3 to 5.

[0023] The compensation mechanism includes a drive shaft 10 and a compensation device 20. The compensation device 20 substantially connects the drive shaft 10 and the movable push-off spiral 4. The compensation device 20 is composed of a plurality of parts, particularly including a hub element 30 and a compensation element 40. The hub element 30 is rotatably arranged on the first eccentric pin 11 of the drive shaft 10. For this purpose, the hub element 30 has a hub hole 31 into which the first eccentric pin 11 fits. A sliding bearing or a needle bearing can be formed between the first eccentric pin 11 and the hub hole 31.

[0024] The hub element 30 includes a holding portion 34 and a scroll portion 35. The holding portion 34 faces the drive shaft 10, while the scroll portion 35 faces the movable push-off spiral 4 and preferably carries a scroll bearing 32. The scroll portion 35 and the holding portion 34 each have a cylindrical outer contour, and the holding portion 34 has a smaller cross-sectional diameter than the scroll portion 35.

[0025] The holding portion 34 holds the compensation element 40. Specifically, the compensation element 40 has a holding hole 41, and the scroll portion 35 penetrates this. The scroll portion 35 extends towards the drive shaft 10 beyond the holding hole 41 and has an annular groove for accommodating the fixing ring 33 in the protruding portion. In this way, the compensation element 40 is fixed to the hub element 30 in the longitudinal axis direction.

[0026] Generally, the compensation element 40 is rotatably supported on the hub element 30. For this purpose, the holding portion 34 can form a sliding bearing for the holding hole 41 of the compensation element 40. By arranging the compensation element 40 rotatably on the hub element 30, it is achieved that the eccentric connection between the first eccentric pin 11 and the movable push-off spiral 4 in the compensation device 20 is disconnected from the balance weight 44. As a result, the space between the push-off spirals 4 and 5 is sealed particularly well. Thereby, the variable compression chamber is well sealed. At the same time, by disconnecting the balance weight 44, a very smooth operation is achieved.

[0027] The compensation element 40 includes a guide portion 43 that carries the holding hole 41. Further, a balance weight 44 that extends substantially in a semi-ring shape or an arc shape around the guide portion 43 is provided. In particular, the balance weight 44 can extend in an arc shape around the holding hole 41. The balance weight 44 preferably has a greater depth than the guide portion 43.

[0028] Furthermore, a slot 42 is positioned in the guide portion 43, extending through the guide portion 43, and the longer transverse axis of the slot 42 is substantially radially aligned with respect to the rotation axis J of the compensation element. The slot 42 receives the second eccentric pin 12 of the drive shaft 10, and the width of the slot 42 along its shorter transverse axis is substantially equal to the diameter of the second eccentric pin 12. The length of the slot 42, measured along its longer transverse axis, is considerably larger than the diameter of the second eccentric pin 12.

[0029] As shown in the assembled state of the compensation device 20 in Figure 4, the first eccentric pin 11 is fitted into the hub hole 31, and the second eccentric pin 12 is fitted into the slot 42. The first eccentric pin 11 extends beyond the compensation element 40 but ends inside the hub hole 31. The second eccentric pin 12 ends inside the slot 42 and therefore does not extend beyond the slot 42.

[0030] Figure 5 is a front view of the compensation device 20, showing the positions of different axes that are deterministic to the motion of the compensation mechanism. The drive shaft 10 has a central axis S that substantially forms the axis of rotation of the drive shaft 10.

[0031] The hub element 30 has a central axis C that extends through the center of the hub element 30. The hub hole 31 of the hub element 30 is formed eccentrically within the hub element 30. The central axis of the hub hole 31 forms the rotation axis P of the hub element 30. Therefore, the hub element 30 rotates about the rotation axis P defined by the central axis of the hub hole 31 or the central axis of the first eccentric pin 11.

[0032] The compensation element 40 rotates around a rotation axis J defined by the central axis of the holding hole 41. In this embodiment, the rotation axis J of the compensation element 40 coincides with the central axis C of the hub element 30. However, it is also possible for the holding hole 41 to be eccentrically aligned with respect to the central axis C of the hub element, so that the rotation axis J of the compensation element 40 is positioned outside the central axis C of the hub element 30. For example, the holding portion 34 of the hub element 30 can be formed eccentrically.

[0033] Slot 42 has a central axis Q that extends in the direction of drilling of slot 42, that is, parallel to the central axis S of the drive shaft 10. The position of the central axis Q of slot 42 is defined by the intersection of the two transverse axes of slot 42.

[0034] The compensation element 40 further has a center of gravity 45 located within the guide portion 43. The center of gravity 45 is preferably located radially outward from the slot 42 or the central axis Q of the slot 42, and “radially outward” should be understood with respect to the rotation axis J of the compensation element 40.

[0035] During operation, a Scotch yoke mechanism is formed between the rotation axis P of the hub element 30, the rotation axis J of the compensation element 40, and the central axis Q of the slot 42. This causes the center of gravity 45 to perform motion during the operation of the compensation device 20, having a linear component extending radially along the connecting line JQ between the rotation axis of the compensation element 40 and the central axis Q of the slot 42, and a pendulum component substantially aligned circumferentially around the rotation axis J of the compensation element 40. The linear component of this motion of the center of gravity 45 is larger than the circumferential or pendulum component. This type of motion, particularly the linear component, results in a significant reduction in vibration and noise within the positive displacement machine.

Claims

1. A compensation mechanism for a positive displacement machine based on the spiral principle, wherein the compensation mechanism comprises a drive shaft (10) having a central axis (S) and a compensation device (20), and the compensation device (20) is A cylindrical hub element (30) is rotatably supported on the first eccentric pin (11) of the drive shaft (10) about a rotation axis (P), The hub element (30) is rotatably supported on the hub element (30) about a rotation axis (J), and the compensation element (40) has a slot (42) that is eccentrically positioned and extends radially with respect to the rotation axis (J), A compensation mechanism in which the second eccentric pin (12) of the drive shaft (10) is guided into the slot (42) of the compensation element (40) such that a Scotch yoke mechanism is formed between the slot (42) and the rotation axis (J) of the compensation element (40).

2. The compensation mechanism according to claim 1, characterized in that the center of gravity (45) of the compensation element (40) has a pendulum component during operation, and the center of gravity (45) reciprocates about the connecting line (JQ) between the rotation axis (J) of the compensation element (40) and the central axis (Q) of the slot (42).

3. The compensation mechanism according to claim 2, characterized in that the center of gravity (45) of the compensation element (40) has a linear component during operation, the center of gravity (45) moves along the connecting line (JQ), and in that case the linear component is larger than the pendulum component.

4. The compensation mechanism according to any one of claims 1 to 3, characterized in that the rotation axis (J) of the compensation element (40) is concentric with the central axis (C) of the hub element (30).

5. The compensation mechanism according to any one of claims 1 to 3, characterized in that the rotation axis (J) of the compensation element (40) is eccentrically positioned with respect to the central axis (C) of the hub element (30).

6. The compensation mechanism according to any one of claims 1 to 3, characterized in that the hub element (30) has an eccentric hub hole (31) in which the first eccentric pin (11) of the drive shaft (10) is located.

7. The compensation mechanism according to any one of claims 1 to 3, characterized in that the compensation element (40) has a retaining hole (41), and the compensation element (40) is rotatably supported on the hub element (30) by the retaining hole (41).

8. The compensation mechanism according to any one of claims 1 to 3, characterized in that the compensation element (40) has a guide portion (43) and a balance weight (44), and the balance weight (44) extends in an arc shape around the guide portion (43).

9. The compensation element (40) has a retaining hole (41) and a guide portion (43), The compensation mechanism according to any one of claims 1 to 3, characterized in that the retaining hole (41) and the slot (42) are arranged in the guide portion (43).

10. The compensation mechanism according to claim 8, characterized in that the balance weight (44) extends in a semi-ring shape around the rotation axis (J) of the compensation element (40).

11. The compensation mechanism according to claim 8, characterized in that the guide portion (43) and the balance weight (44) are integrally formed.

12. The compensation mechanism according to any one of claims 1 to 3, characterized in that the first eccentric pin (11) of the drive shaft (10) has a larger diameter and / or a larger length than the second eccentric pin (12) of the drive shaft (10).

13. The compensation mechanism according to any one of claims 1 to 3, characterized in that the hub element (30) protrudes from the compensation element (40) along the central axis (C) of the hub element (30).

14. The compensation mechanism according to any one of claims 1 to 3, characterized in that the hub element (30) is rotatably supported on the first eccentric pin (11) of the drive shaft (10) via a sliding bearing or a needle bearing, and / or the compensation element (40) is rotatably supported on the hub element (30) via a sliding bearing or a needle bearing.

15. A positive displacement machine based on the spiral principle, comprising a compensation mechanism according to any one of claims 1 to 3.

16. The positive displacement machine according to claim 15, characterized in that the hub element (30) supports a scroll bearing connected to a movable displacement spiral, and the movable displacement spiral engages with a fixed displacement spiral.

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