Hydraulic motor

Claim 2

An hydraulic motor comprising an input shaft, an output shaft, a stationary member, an inlet and outlet for hydraulic fluid, a motor operable to move the output shaft relative to the stationary member, said motor comprising a plurality of pistons located one in each of a like plurality of cylinders, the pistons cooperating with a cam surface whereby when the working spaces within the cylinders behind the pistons are pressurized and exhausted in appropriate sequence the output shaft is moved relative to the stationary member, the motor being characterized by a ported device a first part of which is fixed with respect to the stationary member, a second part of which is fixed with respect to the input shaft and a third part of which is fixed with respect to the output shaft, the ported device serving to control hydraulic fluid flow between the inlet and outlet and the working spaces, the arrangement being such that when the position of the output shaft corresponds to the position of the input shaft communication between the inlet and outlet and the working spaces is prevented by the ported device, and that displacement of the input shaft and said second part of the ported device relative to the stationary member causes communication between the working spaces and the inlet and outlet to be so created that the output shaft and with it the third part of the ported device is moved by the motor to a position corresponding to the new position of the input shaft at which position communication between the working spaces and the inlet and outlet is prevented by the ported device, and that displacement of the output shaft and with it the third part of the ported device relative to the stationary member and the input shaft causes communication between the working spaces and the inlet and outlet to be so created that the output shaft is returned by the motor to a position corresponding to that of the input shaft and when so returned communication between the working spaces and the inlet and outlet is prevented by the ported device; there are two sets of passages in the third part of the ported device on opposite sides of and connecting with passages in the second part of the ported device, the passages on one side of the third part being angularly offset from the passages on the other side of the third part by a predetermined angle equal to the angle subtended at the axis of the motor by one of said passages in the second part.

Claim 3

A servomotor according to claim 1 characterized by this, that the motor is driven by an electric stepping motor, the servomotor being employed to amplify the torque of the electric stepping motor.

Claim 4

A hydraulic motor in which at least one piston reciprocates within at least one cylinder and having a stationary member, an input member and an output member, in which the output member follows the movements of the input member and having: a. a supply of high pressure fluid; b. an exhaust outlet; c. first valve means controlled by relative movement of input member and output member; d. second valve means operated by relative movement of output member and stationary member to connect all each cylinder sequentially to said supply of high pressure fluid and to said exhaust outlet; e. first conduits connecting each cylinder to said first valve means; f. second conduits connecting said first valve means to said second valve means; and g. third conduits connecting said second valve means to said supply of high pressure fluid and to said exhaust outlet.

Claim 5

A hydraulic motor in which at least one piston reciprocates within at least one cylinder and having a stationary member, an input member and an output member, in which the output member follows the movements of the input member and having: a. a supply of high pressure fluid; b. an exhaust outlet; c. first valve means controlled by relative movement of input member and output member; d. second valve means operated by relative movement of output member and stationary member to connect all each cylinder sequentially to said supply of high pressure fluid and to said exhaust outlet; e. first conduits connecting each cylinder to said first valve means; f. second conduits connecting said first valve means to said second valve means; and g. third conduits connecting said second valve means to said supply of high pressure fluid and to said exhaust outlet.

Claim 6

A hydraulic motor according to claim 3, having: a. each cylinder carried by the output member, and b. a cooperating cam track, carried by the stationary member, the driving force of the motor being obtained from the reaction of each piston against this track.

Claim 7

A hydraulic motor according to claim 3, in which: a. said second conduits comprise a first and a second set of conduits, and b. said first valve means is operated by relative movement of Said input and output members to connect said first conduits to one only of said first and second sets, according to the sense of displacement between said input and output members.

Claim 8

A hydraulic motor according to claim 4 in which: a. the output member rotates; and b. the cam track is of the multilobe type, so that each piston reciprocates more than once per revolution of the output member.

Claim 9

An hydraulic motor comprising an input shaft, an output shaft, a stationary member, an inlet and outlet for hydraulic fluid, a motor operable to move the output shaft relative to the stationary member, said motor comprising a plurality of pistons located one in each of a like plurality of cylinders, the pistons cooperating with a cam surface whereby when the working spaces within the cylinders behind the pistons are pressurized and exhausted in appropriate sequence the output shaft is moved relative to the stationary member, the motor being characterized by a ported device a first part of which is fixed with respect to the stationary member, a second part of which is fixed with respect to the input shaft and a third part of which is fixed with respect to the output shaft, the ported device serving to control hydraulic fluid flow between the inlet and outlet and the working spaces, the arrangement being such that when the position of the output shaft corresponds to the position of the input shaft communication between the inlet and outlet and the working spaces is prevented by the ported device, and that displacement of the input shaft and said second part of the ported device relative to the stationary member causes communication between the working spaces and the inlet and outlet to be so created that the output shaft and with it the third part of the ported device is moved by the motor to a position corresponding to the new position of the input shaft at which position communication between the working spaces and the inlet and outlet is prevented by the ported device, and that displacement of the output shaft and with it the third part of the ported device relative to the stationary member and the input shaft causes communication between the working spaces and the inlet and outlet to be so created that the output shaft is returned by the motor to a position corresponding to that of the input shaft and when so returned communication between the working spaces and the inlet and outlet is prevented by the ported device; there are two sets of passages in the third part of the ported device on opposite sides of and connecting with passages in the second part of the ported device, the passages on one side of the third part being angularly offset from the passages on the other side of the third part by a predetermined angle different from the angle subtended at the axis of the motor by a predetermined angle, whereby the axes of adjacent passages are out of alignment by a predetermined amount.

Claim 10

An hydraulic motor comprising an input shaft, an output shaft, a stationary member, an inlet and outlet for hydraulic fluid, a motor operable to move the output shaft relative to the stationary member, said motor comprising a plurality of pistons located one in each of a like plurality of cylinders, the pistons cooperating with a cam surface whereby when the working spaces within the cylinders behind the pistons are pressurized and exhausted in appropriate sequence the output shaft is moved relative to the stationary member, the motor being characterized by a ported device a first part of which is fixed with respect to the stationary member, a second part of which is fixed with respect to the input shaft and a third part of which is fixed with respect to the output shaft, the ported device serving to control hydraulic fluid flow between the inlet and outlet and the working spaces, the arrangement being such that when the position of the output shaft corresponds to the position of the input shaft communication between the inlet and outlet and the working spaces is prevented by the ported device, and that displacement of the input shaft and said second part of the ported device relative to the stationary member causes communication between the working spaces and the inlet and outlet to be so created that the output shaft and with it the third part of the ported device is moved by the motor to a position corresponding to the new position of the input shaft at which position communication between the working spaces and the inlet and outlet is prevented by the ported device, and that displacement of the output shaft and with it the third part of the ported device relative to the stationary member and the input shaft causes communication between the working spaces and the inlet and outlet to be so created that the output shaft is returned by the motor to a position corresponding to that of the input shaft and when so returned communication between the working spaces and the inlet and outlet is prevented by the ported device; there are two sets of passages in the third part of the ported device on opposite sides of and connecting with passages in the second part of the ported device, the passages on one side of the third part being angularly offset from the passages on the other side of the third part by a predetermined angle different from the angle subtended at the axis of the motor by a predetermined angle, whereby the axes of adjacent passages are out of alignment by a predetermined amount.

Claim 11

The hydraulic motor of claim 1 wherein said pistons are all ball-shaped.

Claim 12

The hydraulic motor of claim 1 wherein said output shaft executes linear movement.

Claim 13

The hydraulic motor of claim 1 wherein said output shaft rotates.