Abstract
A refrigerant compressor including a compressor housing, a drive shaft for driving a compression mechanism, which is arranged within the compressor housing, a main bearing via which the drive shaft is supported on the compressor housing and which includes an inner ring fixed to the drive shaft and an outer ring pressed into the compressor housing, wherein protruding tooth-like protrusions which press into an adjacent wall of the compressor housing are arranged on an end face of the outer ring in the direction of the ring axis of the outer ring. This is sufficient to prevent rotation of the outer ring even when there is no longer a press fit in the radial direction between the outer ring of the bearing and the compressor housing.
Claims
1-10. (canceled)
11. A refrigerant compressor, comprising: a compressor housing; and a drive shaft for driving a compression mechanism, which is arranged within the compressor housing, a main bearing via which the drive shaft is supported on the compressor housing and which comprises an inner ring fixed to the drive shaft and an outer ring pressed into the compressor housing, wherein protruding tooth-like protrusions which press into an adjacent wall of the compressor housing are arranged on an end face of the outer ring in a direction of a ring axis of the outer ring.
12. The refrigerant compressor according to claim 11, wherein a material of the compressor housing is plastically deformed through the tooth-like protrusions.
13. The refrigerant compressor according to claim 11, wherein there is a form-fit connection between the main bearing and the compressor housing.
14. The refrigerant compressor according to claim 11, wherein the tooth-like protrusions respectively extend individually in a radial direction over a complete width of the end face.
15. The refrigerant compressor according to claim 11, wherein the tooth-like protrusions are arranged uniformly distributed in a circumferential direction over a complete circumference of the outer ring.
16. The refrigerant compressor according to claim 11, wherein the outer ring is manufactured in one piece.
17. The refrigerant compressor according to claim 16, wherein the outer ring is manufactured in the one piece in a forging process.
18. The refrigerant compressor according to claim 17, wherein the tooth-like protrusions are created in a forging process together with the outer ring.
19. The refrigerant compressor according to claim 11, wherein the refrigerant compressor is a scroll compressor.
20. The refrigerant compressor according to claim 11, wherein the main bearing is a ball bearing.
Description
BRIEF DESCRIPTION OF DRAWINGS
[0020] In the drawings:
[0021] FIG. 1: shows a thermal compensation bearing, prior art,
[0022] FIG. 2: shows a sectional diagram of a portion of an electrical refrigerant compressor in the region of the main bearing of the shaft for driving the compression mechanism,
[0023] FIG. 3A: shows a perspective diagram of the outer ring of the main bearing,
[0024] FIG. 3B: shows a view of a section of the outer ring of the main bearing towards the ball race thereof, and
[0025] FIG. 4: shows a schematic diagram of the finishing of the outer ring, starting from a cast blank after casting.
DESCRIPTION OF AN EMBODIMENT
[0026] FIG. 1 shows a ball bearing A according to the prior art, which is designed as a thermal compensation bearing in order to prevent rotation of a bearing even in the case of a temperature increase. The ball bearing A comprises an outer ring B, an inner ring C, and a likewise annular bearing cage D, which is arranged in the radial direction between the outer ring B and the inner ring C and into which, distributed over the circumference of the bearing cage, balls E are inserted as rolling elements and are spaced from one another in order to reduce the frictional resistance. The ball bearing shown in FIG. 1 is a thermal compensation bearing as offered for example by SBN Walzlager GmbH & Co. KG, in which grooves F are milled into the outer ring B of the bearing. Plastic rings G are inserted into these grooves F. These plastic rings G have the same or a higher coefficient of thermal expansion than a compressor housing (not shown in FIG. 1), which consists of aluminum. The higher thermal coefficient of the plastic rings G ensures sufficiently high press-fitting even at higher temperatures. The disadvantage of such a solution is that multiple additional process steps are necessary to manufacture the thermal compensation bearing. Firstly, the outer ring B of the ball bearing A must be machined to produce the grooves F. Additionally, the plastic rings G must be manufactured using an injection molding method and introduced into the grooves F.
[0027] FIG. 2 shows a sectional diagram of a portion 1 of an electrical refrigerant compressor in which the main bearing 2 of a shaft 3, referred to below as drive shaft 3, is situated. In electrical refrigerant compressors, the drive shaft 3 is used to drive a compression mechanism, for example to drive the mechanism of a scroll compressor, wherein both the drive shaft 3 and the other components necessary for the compression mechanism are arranged inside a compressor housing 4. A scroll compressor, also referred to as a spiral compressor, comprises as components for the compression mechanism two interleaving spirals inside the compressor housing 4, one spiral being stationary, and the other spiral being movable eccentrically as an orbiting spiral on a circular trajectory, and the volume of compression chambers formed between the spirals can be changed cyclically by the movement of the spiral. In the scroll compressor, the drive shaft 3 drives the orbiting spiral.
[0028] To guide the drive shaft 3 and to ensure operation which is as wear-free as possible, the drive shaft is supported by the main bearing 2. The main bearing 2 has an outer ring 5 which is press-fitted in the compressor housing 4. This press fit ensures that the outer ring 5 cannot rotate. In the case shown in FIG. 2, the main bearing is a ball bearing 2 having the outer ring 5, an inner ring 6 which is fixed to the drive shaft 3, and balls 7 as rolling elements 7 arranged between the outer ring 5 and the inner ring 6.
[0029] As can be seen in FIG. 2, tooth-like protrusions 9, which are also referred to below as teeth 9, protruding axially, i.e., in the direction of the ring axis 8 of the outer ring 5, are arranged on an end face 5a of the outer ring 5 of the main bearing 2.
[0030] FIG. 2 schematically shows how the main bearing with the axially protruding teeth 9 on the outer ring 5 is pressed into the compressor housing 4 such that the teeth 9 press into an adjacent wall 4a of the compressor housing 4. This state is also referred to as axial toothing of the main bearing. The pressing-in force can be selected such that the teeth 9 plastically deform the material of the compressor housing 4. These plastic deformations in the compressor housing 4 have the same shape as the teeth 9 of the outer ring 5 of the main bearing 2. This results in a form-fit connection between these two components, i.e., the main bearing 2 and the compressor housing 4. This is sufficient to prevent rotation even when there is no longer a press fit in the radial direction, in relation to the outer ring 5, between the outer ring of the main bearing and the compressor housing. This means that, owing to the form-fit connection between the main bearing 2 and the compressor housing 4, securing against rotation of the outer ring 5 of the main bearing is independent of temperatures and the different press fits resulting therefrom.
[0031] FIG. 3A shows a perspective view of the outer ring 5 of the main bearing towards the circular ring-shaped end face 5a with a plurality of axially protruding teeth 9. The teeth 9, which respectively extend individually in the radial direction over the complete width of the end face 5a, are arranged uniformly distributed in the circumferential direction over the complete circumference of the outer ring 5. In the exemplary embodiment shown in FIG. 3A, the axially protruding teeth 9, of which there are 12 in total, are distributed over the circular ring-shaped end face 5a of the outer ring 5 in the manner of numerals on the face of a clock. On the inside of the outer ring 5, a ball race 10 with a concave cross-section adapted to the ball shape runs over the entire inner circumference of the outer ring 5. FIG. 3B shows a detail view of a section of the outer ring 5 of the main bearing towards the ball race 10 thereof. FIG. 3B also shows the axially protruding teeth 9 of this section. They are approximately 5 times wider in the circumferential direction than their height with which they axially protrude and which is approximately 0.2 mm. The dimensions should preferably be selected such that the pressing-in force is sufficient to deform the housing plastically until the teeth are fully embedded in the housing. In addition, it should be ensured that the plastic deformation remains so small that any influence on further functions and components of the compressor is excluded as far as possible. The use of twelve teeth 9 each having a width of 1 mm and an embedding depth of 0.2 mm has proven particularly advantageous and practicable for the specific application. The exact dimensions can be redefined and evaluated in each case for different applications.
[0032] FIG. 4 schematically shows the order in which the outer ring should practically be finished and how the manufacture of the outer ring is simplified thereby. In contrast to the thermal compensation bearing shown in FIG. 1, the outer ring of the axially toothed main bearing can be manufactured in one piece. In a thermal compensation bearing, the grooves must be milled into the outer ring; cf. FIG. 1. The plastic rings must then be inserted into the grooves. These additional work steps are not necessary in the main bearing used according to the invention, the outer ring of which is provided with axially protruding teeth, since the manufacture of the teeth can be part of the forging process for manufacturing the outer ring.
[0033] This means that the forging tool of the outer ring can be designed such that the teeth are already produced in the forging process. As a result, no further machining steps other than the machining steps I to IV mentioned below for machining the cast blank are necessary. No additional components are needed either.
[0034] First, the front side of the cast blank is post-machined in step I. In step II, the rear side is post-machined. In a subsequent step III, the cast blank is machined correspondingly in the region of the outer diameter. Finally, in step IV, the inner ball race is also subjected to post-machining.
LIST OF REFERENCE NUMERALS
[0035] 1 Portion of an electrical refrigerant compressor [0036] 2 Main bearing, ball bearing [0037] 3 Drive shaft [0038] 4 Compressor housing [0039] 4a Wall of compressor housing [0040] 5 Outer ring [0041] 5a End face of outer ring [0042] 6 Inner ring [0043] 7 Ball, rolling element [0044] 8 Ring axis of outer ring [0045] 9 Tooth-like protrusions, teeth [0046] 10 Ball race of outer ring
