HYDRAULIC MACHINE WITH A THREADED CENTRAL PIN FOR SETTING MACHINE PRELOAD
Systems and methods for a hydraulic machine. The hydraulic machine includes, in one example, a rotational shaft, a central pin rotationally coupled to the rotational shaft and threadingly engaged with a cylinder block via a threaded interface, and pistons coupled to the rotational shaft and mated with cylinders in the cylinder block. The hydraulic machine further includes a distribution plate in fluidic communication with the cylinders and a fluid inlet and a fluid outlet.
1 . A hydraulic machine, comprising:
a rotational shaft;
a central pin rotationally coupled to the rotational shaft and threadingly engaged with a cylinder block via a threaded interface;
a plurality of pistons coupled to the rotational shaft and mated with a plurality of cylinders in the cylinder block; and
a distribution plate in fluidic communication with the plurality of cylinders and a fluid inlet and a fluid outlet.
2 . The hydraulic machine of claim 1 , further comprising a threaded retainer ring positioned in the cylinder block and axially delimiting the central pin.
3 . The hydraulic machine of claim 1 , further comprising a tailstock pin threadingly engaged with the distribution plate and mated with a central recess in the cylinder block.
4 . The hydraulic machine of claim 3 , further comprising a seal formed between the tailstock pin, the cylinder block, and the distribution plate.
5 . The hydraulic machine of claim 1 , further comprising a seal formed between the distribution plate and the cylinder block.
6 . The hydraulic machine of claim 1 , wherein an interface between the central pin and the cylinder block does not include a spring.
7 . The hydraulic machine of claim 1 , further comprising a bearing coupled to the rotational shaft and a housing.
8 . The hydraulic machine of claim 1 , wherein the hydraulic machine is a bent axis hydraulic motor.
9 . The hydraulic machine of claim 8 , wherein the bend axis hydraulic motor is included in a hydrostatic transmission.
10 . A method for operation of a first hydraulic machine, comprising:
rotating a rotational shaft while a preload force is exerted on a distribution plate by a cylinder block;
wherein an amount of preload force is dictated by an amount of threaded engagement between a central pin and the cylinder block; and
wherein the first hydraulic machine includes:
the rotational shaft;
the central pin rotationally coupled to the rotational shaft and threadingly engaged with the cylinder block;
a plurality of pistons coupled to the rotational shaft and mated with a plurality of cylinders in the cylinder block; and
the distribution plate in fluidic communication with the plurality of cylinders and a fluid inlet and a fluid outlet.
11 . The method of claim 10 , further comprising flowing a fluid from the fluid outlet to a second hydraulic machine.
12 . The method of claim 11 , wherein the second hydraulic machine is a hydraulic pump.
13 . The method of claim 12 , wherein the hydraulic pump is included in a hydrostatic transmission.
14 . A bent axis hydraulic machine, comprising:
a rotational shaft;
a central pin rotationally coupled to the rotational shaft and threadingly engaged with a cylinder block;
a plurality of pistons coupled to the rotational shaft and mated with a plurality of cylinders in the cylinder block; and
a distribution plate in fluidic communication with the plurality of cylinders and a fluid inlet and a fluid outlet;
wherein the cylinder block exerts a preload force on the distribution plate that is based on an amount of threaded engagement between the central pin and the cylinder block.
15 . The bent axis hydraulic machine of claim 14 , further comprising a tailstock pin threadingly engaged with the distribution plate, mated with a central recess in the cylinder block, and in face sharing contact with an end of the central pin.
16 . The bent axis hydraulic machine of claim 14 , further comprising a sealing assembly configured to seal the cylinder block and the distribution plate.
17 . The bent axis hydraulic machine of claim 16 , wherein the sealing assembly includes a first seal which is arranged between the cylinder block and the distribution plate and positioned radially outward from the fluid inlet and the fluid outlet.
18 . The bent axis hydraulic machine of claim 17 , wherein the sealing assembly includes a second seal which is arranged between the cylinder block, the distribution plate, and a tailstock pin threadingly engaged with the distribution plate, mated with a central recess in the cylinder block.
19 . The bent axis hydraulic machine of claim 14 , wherein the bent axis hydraulic machine is a bent axis motor that is in fluidic communication with a hydraulic pump.
20 . The bent axis hydraulic machine of claim 14 , wherein the central pin does not include a spring positioned therein or directly coupled thereto.