Bent axis machine

A bent axis machine is a device that is used in hydraulics as an axial piston pump to convert mechanical energy ( torque , speed ) into hydraulic energy ( volume flow , pressure) or as an axial piston motor to convert hydraulic energy (volume flow, pressure ) into mechanical energy (torque, speed) is used. The bent axis machine was registered for a patent in 1929 by the engineers Hans Thoma and Heinrich Kosel . According to the system of the hydraulic designer and pioneer Hans Molly , the bent axis machine is also referred to as the MH machine .

construction

Basic structure

Inside the bent-axis machine there is a ring with circularly arranged cylinder bores into which finger pistons (hereinafter referred to as “pistons”) are inserted in the same arrangement ; the ring is called the piston housing (hereinafter “housing”). Similar to the swashplate machine , the pistons are connected to a wheel-shaped sliding disk via articulated bearings. The axis of the housing (and thus the piston) forms an angle with the axis of the sliding washer . With adjustable machines, the angle can be changed. This type of connection between piston and sliding washer is called axial. ${\ displaystyle \ alpha}$ ${\ displaystyle \ alpha}$

The angle has the effect that the penetration depth of a piston in the housing passes through a maximum and a minimum during one rotation. ${\ displaystyle \ alpha}$

Pumps and motors are similar in structure. If the machine is used as a hydraulic pump , the pistons are pulled out of the housing on one side and pushed in on the other side. This creates suction on the side on which the pistons emerge from the housing, while pressure on the other side, with which the machine transports a delivery or absorption volume . Conversely, this volume is zero as long as the sliding washer and housing are in one line ( ). ${\ displaystyle \ alpha = 0}$

Conversely, if the machine is used as a hydraulic motor , different pressures on different sides of the housing cause the sliding disk to rotate. This pressure can in turn be generated by a hydraulic pump , so that both applications of the bent axis machine are combined. Such a combination forms a hydrostatic transmission .

Patent drawings from US1736754

Types

Three different types of axial piston machines with an inclined axis are common:

Bevel gear drive (Volvo type)

The cylinder drum is synchronized with the drive shaft by means of bevel gears. The axis angle is not adjustable here, but the mechanism is particularly robust and durable.

propeller shaft

Here the cylinder drum is synchronized by means of a cardan shaft with cardan joints or curved tooth couplings . The axis angle is adjustable, but the mechanics are sensitive to jerky, reversing operation.

Entrainment by the piston

The cylinder is taken along by the pistons (Bosch-Rexroth)

A bent axis pump in section
animation

Individual evidence

^ Hans Jürgen Matthies , Karl Theodor Renius: Introduction to oil hydraulics. 6th, updated and expanded edition. Vieweg + Teubner, Wiesbaden 2008, ISBN 978-3-8351-0238-5 . P. 20.
^ Hans Jürgen Matthies, Karl Theodor Renius: Introduction to oil hydraulics. 6th, updated and expanded edition. Vieweg + Teubner, Wiesbaden 2008, ISBN 978-3-8351-0238-5 . P. 71 .
↑ pump or motor - US 1736754 A . From google.com, accessed October 16, 2016

[Eidöh20-1] Hans Jürgen Matthies , Karl Theodor Renius: Introduction to oil hydraulics. 6th, updated and expanded edition. Vieweg + Teubner, Wiesbaden 2008, ISBN 978-3-8351-0238-5 . P. 20.

[Eidöh71-2] Hans Jürgen Matthies, Karl Theodor Renius: Introduction to oil hydraulics. 6th, updated and expanded edition. Vieweg + Teubner, Wiesbaden 2008, ISBN 978-3-8351-0238-5 . P. 71 .

[US1736754-3] pump or motor - US 1736754 A . From google.com, accessed October 16, 2016