Hybrid construction machine
First Claim
1. A hybrid construction machine comprising:
- a prime mover;
a hydraulic pump driven by the prime mover;
a swing structure;
an electric motor for driving the swing structure;
a hydraulic motor for driving the swing structure, and the hydraulic motor being driven by the hydraulic pump;
an electricity storage device connected to the electric motor;
a swing control lever device which outputs a command regarding the driving of the swing structure;
a first control device which switches a swing mode regarding the driving of the swing structure between;
a hydraulic/electric hybrid swing mode for driving the swing structure by a total torque of the electric motor and the hydraulic motor by driving both the electric motor and the hydraulic motor when the swing control lever device is operated, anda hydraulic-alone swing mode for driving the swing structure by a torque of the hydraulic motor alone by driving only the hydraulic motor when the swing control lever device is operated;
a second control device which controls transfer of electric power between the electricity storage device and the electric motor; and
a swing hydraulic system which includes a swing spool for controlling the flow of hydraulic fluid supplied from the hydraulic pump to the hydraulic motor and the flow of the hydraulic fluid returned from the hydraulic motor to a tank,wherein the swing hydraulic system is switchable between a first mode in which a maximum output torque of the hydraulic motor equals a first torque and a second mode in which the maximum output torque of the hydraulic motor equals a second torque that is higher than the first torque, andwherein the first control device includes;
a hydraulic/electric hybrid swing control unit which switches the swing hydraulic system to the first mode and which outputs a torque command to the second control device and thereby drives the electric motor when the swing control lever device is operated,a hydraulic-alone swing control unit which switches the swing hydraulic system to the second mode and stops the output of the torque command to the second control device, andswitching between the hydraulic/electric hybrid swing mode and the hydraulic-alone swing mode by selecting one of the hydraulic/electric hybrid swing control unit and the hydraulic-alone swing control unit.
1 Assignment
0 Petitions
Accused Products
Abstract
A hybrid construction machine is capable of performing satisfactory operations even when trouble occurs that disables the electric motor from outputting torque. The hybrid construction has both a hydraulic motor and an electric motor driving the swing structure and a controller for switching between a hydraulic/electric hybrid swing mode (using both the hydraulic motor and the electric motor) and a hydraulic-alone swing mode (using only the hydraulic motor). The switching is executed while achieving satisfactory operability and performance in each mode. Normally, an energy saving operation is performed in the hydraulic/electric hybrid swing mode. When the electric amount of an electricity storage device has gone out of a prescribed range or an abnormality has occurred in an electric system (e.g., failure of an inverter), the swing mode is switched to the hydraulic-alone swing mode so that driving with normal braking torque is possible by the hydraulic motor alone.
15 Citations
14 Claims
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1. A hybrid construction machine comprising:
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a prime mover; a hydraulic pump driven by the prime mover; a swing structure; an electric motor for driving the swing structure; a hydraulic motor for driving the swing structure, and the hydraulic motor being driven by the hydraulic pump; an electricity storage device connected to the electric motor; a swing control lever device which outputs a command regarding the driving of the swing structure; a first control device which switches a swing mode regarding the driving of the swing structure between; a hydraulic/electric hybrid swing mode for driving the swing structure by a total torque of the electric motor and the hydraulic motor by driving both the electric motor and the hydraulic motor when the swing control lever device is operated, and a hydraulic-alone swing mode for driving the swing structure by a torque of the hydraulic motor alone by driving only the hydraulic motor when the swing control lever device is operated; a second control device which controls transfer of electric power between the electricity storage device and the electric motor; and a swing hydraulic system which includes a swing spool for controlling the flow of hydraulic fluid supplied from the hydraulic pump to the hydraulic motor and the flow of the hydraulic fluid returned from the hydraulic motor to a tank, wherein the swing hydraulic system is switchable between a first mode in which a maximum output torque of the hydraulic motor equals a first torque and a second mode in which the maximum output torque of the hydraulic motor equals a second torque that is higher than the first torque, and wherein the first control device includes; a hydraulic/electric hybrid swing control unit which switches the swing hydraulic system to the first mode and which outputs a torque command to the second control device and thereby drives the electric motor when the swing control lever device is operated, a hydraulic-alone swing control unit which switches the swing hydraulic system to the second mode and stops the output of the torque command to the second control device, and switching between the hydraulic/electric hybrid swing mode and the hydraulic-alone swing mode by selecting one of the hydraulic/electric hybrid swing control unit and the hydraulic-alone swing control unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification