Patent ID: 8720535

Claim:
A heat exchanger for heat transfer between a first fluid and a second fluid, the heat exchanger comprising: a block for separated and heat-exchanging guiding of the first and second fluid, the block having a plurality of flow channels through which the first fluid is flowable; at least one box that is assigned to the block and that is flow-connected to the flow channels; and at least one base, which is provided with one or more through openings for feeding through the flow channels between the block and the box, at least one through opening being configured as a passage with a collar, wherein the collar is configured to mitigate damage due to thermal cycling, the collar having on at least one side a near-bottom section and an end-side section, wherein, between the near-bottom section and end-side section, at least one shoulder is disposed that has a shoulder contour forming an outer side surface of the collar, the outer side surface extending transverse to a passage axis of the openings, such that a wall thickness of the end-side section is smaller than a wall thickness of the near-bottom section, and wherein an outer edge of the shoulder is aligned with an outer edge of the near-bottom section, and wherein the end-side section is inclined away from the passage axis, such that outer edges of the end-side section extend outside of outer edges of the near-bottom section in the direction extending away from the passage axis.