Latching pin assembly and deactivating rocker arm assembly
A latch assembly ( 500 ) can comprise a main latch pin assembly ( 531, 532 ) comprising a first diameter (D 1 ) on a first main pin face ( 512, 522 ), and a secondary latch piston ( 541, 561 ) comprising a second diameter (D 2 ) on a secondary piston face ( 543, 563 ). The secondary latch piston can be configured to selectively act on the main latching pin assembly. The main latch pin assembly can be biased to oppose the secondary latch piston. The first diameter can be greater than the second diameter. A rocker arm assembly ( 10 ) can comprise the latch assembly. A primary arm ( 100 ) can be configured to receive the main latch pin assembly. A secondary arm ( 300 ) can be configured to receive the secondary latch piston.
1. A latch assembly, comprising:
a main latch pin assembly comprising a first diameter on a first main pin face and a main pin body that is stepped from an outer diameter to the first diameter, and
a secondary latch piston comprising a second diameter on a secondary piston face,
wherein the secondary latch piston is configured to selectively act on the main latching pin assembly,
wherein the main latch pin assembly is biased to oppose the secondary latch piston, and
wherein the first diameter is greater than the second diameter.
2. The latch assembly of claim 1 , wherein the main pin body comprises at least one anti-rotation flat.
3. A rocker arm assembly, comprising the latch assembly of claim 1 and further comprising:
a primary arm configured to receive the main latch pin assembly; and
a secondary arm configured to receive the secondary latch piston.
4. The rocker arm assembly of claim 3 , wherein:
the primary arm comprises a latch shelf proximal a primary rocker shaft bore, and the main latch pin assembly is installed in a primary latch bore in the latch shelf,
the secondary arm comprises a latch extension proximal a secondary rocker shaft bore, and the secondary latch piston is installed in a secondary latch bore in the latch extension.
5. The rocker arm assembly of claim 4 , wherein the secondary latch bore is stepped from a first inner diameter guiding the secondary latch piston to a second inner diameter that is larger than the first inner diameter.
6. The rocker arm assembly of claim 5 , wherein the main latch pin assembly is biased to abut the second inner diameter when the secondary latch piston is passive.
7. The rocker arm assembly of claim 4 , wherein:
the primary arm comprises a primary travel limit,
the secondary arm comprises a secondary travel limit, and
the secondary travel limit contacts the primary travel limit when the latch assembly is latched, but the secondary travel limit is configured to swing away from the primary travel limit when the latch assembly is unlatched.
8. The rocker arm assembly of claim 4 , wherein the latch shelf comprises an anti-rotation bore and an anti-rotation pin installed in the anti-rotation bore, and wherein the main latch pin assembly comprises at least one anti-rotation flat configured to reciprocate across the anti-rotation pin.
9. The rocker arm assembly of claim 3 , comprising a lost motion spring assembly spanning from the primary arm to the secondary arm.
10. The rocker arm assembly of claim 3 , comprising a bearing end on the secondary arm and a valve end on the primary arm.
11. The rocker arm assembly of claim 10 , wherein the bearing end, the valve end, and the latch assembly are configured to surround a rocker shaft in a triangular distribution.
12. The rocker arm assembly of claim 3 , wherein the primary arm comprises a lubrication port to the main latch pin assembly.
13. The rocker arm assembly of claim 3 , wherein the secondary arm comprises an actuation port to the secondary latch piston.
14. The rocker arm assembly of claim 13 , wherein the secondary latch piston comprises a piston body cupped to receive an actuation fluid.
15. A latch assembly of claim 1 , comprising:
a main latch pin assembly comprising a first diameter on a first main pin face, and
a secondary latch piston comprising a second diameter on a secondary piston face,
wherein the secondary latch piston comprises a piston body cupped to receive an actuation fluid,
wherein the secondary latch piston is configured to selectively act on the main latching pin assembly,
wherein the main latch pin assembly is biased to oppose the secondary latch piston, and
wherein the first diameter is greater than the second diameter.
16. The latch assembly of claim 15 , wherein the piston body is crenelated to form an actuation fluid passage.
17. A rocker arm assembly, comprising:
a latch assembly comprising:
a main latch pin assembly comprising a first diameter on a first main pin face, and
a secondary latch piston comprising a second diameter on a secondary piston face,
wherein the secondary latch piston is configured to selectively act on the main latching pin assembly,
wherein the main latch pin assembly is biased to oppose the secondary latch piston, and
wherein the first diameter is greater than the second diameter;
a primary arm configured to receive the main latch pin assembly, the primary arm comprises a latch shelf proximal a primary rocker shaft bore, and the main latch pin assembly is installed in a primary latch bore in the latch shelf; and
a secondary arm configured to receive the secondary latch piston, the secondary arm comprises a latch extension proximal a secondary rocker shaft bore, and the secondary latch piston is installed in a secondary latch bore in the latch extension,
wherein the secondary latch bore is stepped from a first inner diameter guiding the secondary latch piston to a second inner diameter that is larger than the first inner diameter,
wherein the main latch pin assembly is biased to abut the second inner diameter when the secondary latch piston is passive,
wherein the main latch pin assembly comprises a main pin body that is stepped from an outer diameter to the first diameter, and wherein a step abuts the second inner diameter when the secondary latch piston is passive.