Seal unit, joint, industrial device and method
A seal unit for being installed in a joint, the seal unit having a first adapting ring concentric with a seal unit axis; a dynamic seal in contact with, and allowed to slide relative to, the first adapting ring; and a holding device configured to adopt two states, at least one of the states being associated with a unique seal unit width of the seal unit along the seal unit axis; wherein the holding device is configured to hold the dynamic seal compressed against the first adapting ring in at least one of the states. A joint, an industrial device and a method of installing a seal unit are also provided.
1 . A seal unit for being installed in a joint, the seal unit comprising:
a first adapting ring concentric with a seal unit axis;
a dynamic seal in contact with, and allowed to slide relative to, the first adapting ring; and
a holding device configured to adopt two states, at least one of the states being associated with a unique seal unit width of the seal unit along the seal unit axis;
wherein the holding device is configured to hold the dynamic seal compressed against the first adapting ring in at least one of the states.
2 . The seal unit according to claim 1 , wherein the holding device is configured to hold the dynamic seal compressed against the first adapting ring in a first state prior to installation of the seal unit in the joint.
3 . The seal unit according to claim 1 , wherein the dynamic seal and the holding device are at least partly positioned in a common plane transverse to the seal unit axis in at least one of the states of the holding device.
4 . The seal unit according to claim 1 , wherein the holding device is connected to the first adapting ring in at least one of the states of the holding device.
5 . The seal unit according to claim 4 , wherein the holding device is disconnected from the first adapting ring in one of the states of the holding device.
6 . The seal unit according to claim 1 , wherein the dynamic seal is arranged to be forced against the first adapting ring in each of the states of the holding device.
7 . The seal unit according to claim 6 , further comprising a seal force device arranged to force the dynamic seal against the first adapting ring in each of the states of the holding device.
8 . The seal unit according to claim 1 , further comprising a second adapting ring concentric with the seal unit axis, wherein the dynamic seal is in contact with, and allowed to slide relative to, the second adapting ring.
9 . The seal unit according to claim 1 , further comprising a separation force device, separated from the dynamic seal and arranged to force the first adapting ring in a direction relaxing the dynamic seal.
10 . The seal unit according to claim 1 , wherein the seal unit comprises a bearing having a first bearing element and a second bearing element, and wherein the first bearing element is immobile with respect to the first adapting ring.
11 . The seal unit according to claim 10 , wherein the bearing is a rolling-element bearing and constitutes the holding device.
12 . A joint comprising:
a first part and a second part rotatable relative to each other about a rotation axis;
a gap between the first part and the second part; and
a seal unit provided in the gap, the seal unit having:
a first adapting ring concentric with a seal unit axis;
a dynamic seal in contact with, and allowed to slide relative to, the first adapting ring; and
a holding device configured to adopt two states, at least one of the states being associated with a unique seal unit width of the seal unit along the seal unit axis;
wherein the holding device is configured to hold the dynamic seal compressed against the first adapting ring in at least one of the states.
13 . The joint according to claim 12 , wherein the gap defines a gap width, and wherein a seal unit width associated with one of the states is defined by the gap width.
14 . An industrial device, such as an industrial robot, comprising:
a joint which has:
a first part and a second part rotatable relative to each other about a rotation axis;
a gap between the first part and the second part; and
a seal unit provided in the gap, the seal unit having:
a first adapting ring concentric with a seal unit axis;
a dynamic seal in contact with, and allowed to slide relative to, the first adapting ring; and
a holding device configured to adopt two states, at least one of the states being associated with a unique seal unit width of the seal unit along the seal unit axis;
wherein the holding device is configured to hold the dynamic seal compressed against the first adapting ring in at least one of the states.
15 . A method of installing a seal unit in a joint, the method comprising:
providing a joint including a first part and a second part rotatable relative to each other about a rotation axis;
providing a seal unit including a first adapting ring concentric with a seal unit axis, a dynamic seal in contact with, and allowed to slide relative to, the first adapting ring; and
adjusting, by means of the seal unit, a seal unit width on a basis of a predefined preload in the dynamic seal.
16 . The seal unit according to claim 2 , wherein the dynamic seal and the holding device are at least partly positioned in a common plane transverse to the seal unit axis in at least one of the states of the holding device.
17 . The seal unit according to claim 2 , wherein the holding device is connected to the first adapting ring in at least one of the states of the holding device.
18 . The seal unit according to claim 2 , wherein the dynamic seal is arranged to be forced against the first adapting ring in each of the states of the holding device.
19 . The seal unit according to claim 2 , further comprising a second adapting ring concentric with the seal unit axis, wherein the dynamic seal is in contact with, and allowed to slide relative to, the second adapting ring.