Shift Control System for Industrial Vehicle

• US 20120296531A1
• Filed: 12/14/2010
• Published: 11/22/2012
• Est. Priority Date: 12/14/2009
• Status: Active Grant

• Current Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Inventors: Hyodo, Koji, Shimazu, Atsushi, Oouchi, Hirofumi, Aoki, Tadayoshi
• Granted Patent: US 8,775,034 B2
• Time in Patent Office: Days
• US Class Current: 701/50
• CPC Class Codes: B60Y 2200/145 Haulage vehicles, trailing trucks
• CPC Class Codes: E02F 9/2079 Control of mechanical transmission for hydrostatic transmission or hydraulic torque converter E02F9/2253
• CPC Class Codes: E02F 9/2253 Controlling the travelling speed of vehicles, e.g. adjusting travelling speed according to implement loads, control of hydrostatic transmission
• CPC Class Codes: E02F 9/264 Sensors and their calibration for indicating the position of the work tool
• CPC Class Codes: F16H 59/08 Range selector apparatus
• CPC Class Codes: F16H 59/50 Inputs being a function of the status of the machine, e.g. position of doors or safety belts
• CPC Class Codes: F16H 61/0213 characterised by the method for generating shift signals
• CPC Class Codes: F16H 61/16 Inhibiting or initiating shift during unfavourable conditions, e.g. preventing forward reverse shift at high vehicle speed, preventing engine over speed unintentional control input F16H61/18

Abstract

A shift control system for an industrial vehicle includes: a vehicle speed detection device that detects a vehicle speed; a transmission device that shifts up and shifts down a speed stage of a transmission; a shift control device that permits shift up when a vehicle speed becomes equal to or greater than a shift up permission vehicle speed; a height position detection device that detects a height position of a working machine device; a forward/backward switch device that switches the industrial vehicle between forward travel and backward travel; and a shift up control switch selection device that switches between normal control, in which shift up is performed by the transmission device when the vehicle speed becomes equal to or greater than the shift up permission vehicle speed, and delay control, in which shift up timing is delayed with respect to the normal control.

Claims

1. A shift control system for industrial vehicle, comprising:

a vehicle speed detection device that detects a vehicle speed of an industrial vehicle;

a transmission device that shifts up and shifts down a speed stage of a transmission;

a shift control device that permits shift up by the transmission device when a vehicle speed detected by the vehicle speed detection device becomes equal to or greater than a shift up permission vehicle speed;

a height position detection device that detects a height position of a working machine device;

a forward/backward switch device that switches the industrial vehicle between forward travel and backward travel; and

a shift up control switch selection device that switches between normal control, in which shift up is performed by the transmission device when the vehicle speed becomes equal to or greater than the shift up permission vehicle speed, and delay control, in which shift up timing is delayed with respect to the normal control.

2. A shift control system for industrial vehicle according to claim 1, wherein:

speed stages at the transmission include 3 speeds or more;

when the delay control has been selected by the shift up control switch selection device, if forward travel is selected by the forward/backward switch device;

the shift control device sets the shift up permission vehicle speed to a first shift up permission vehicle speed if a height position of the working machine device that is detected by the height position detection device is lower than a setting value, and sets the shift up permission vehicle speed to a second shift up permission vehicle speed that is greater than the first shift up permission vehicle speed if a height position of the working machine device is equal to or greater than the setting value; and

when a height position of the working machine device is equal to or greater than the setting value, the shift control device controls the transmission device so that a speed stage at the transmission is shifted up from speed 2 to speed 3 if the vehicle speed has continued to be equal to or greater than the second shift up permission vehicle speed for a forward travel setting time.

3. A shift control system for industrial vehicle according to claim 1, wherein:

speed stages at the transmission include 3 speeds or more;

when the delay control has been selected by the shift up control switch selection device, if backward travel is selected by the forward/backward switch device;

the shift control device sets the shift up permission vehicle speed to a second shift up permission vehicle speed that is greater than a first shift up permission vehicle speed, regardless of a height of the working machine device, and controls the transmission device so that a speed stage at the transmission is shifted up from speed 2 to speed 3 if the vehicle speed has continued to be equal to or greater than the second shift up permission vehicle speed for a backward travel setting time.

4. A shift control system for industrial vehicle according to claim 1, wherein:

speed stages at the transmission include 3 speeds or more;

the shift control device sets the shift up permission vehicle speed to a first shift up permission vehicle speed when the normal control has been selected by the shift up control switch selection device regardless of a height of the working machine device and setting of the forward/backward switch device, and controls the transmission device so as to shift up a speed stage at the transmission from speed 2 to speed 3 when the vehicle speed becomes equal to or greater than the first shift up permission vehicle speed.

5. A wheel loader, comprising a shift control system according to claim 1.

6. A shift control system for industrial vehicle according to claim 2, wherein:

speed stages at the transmission include 3 speeds or more;

when the delay control has been selected by the shift up control switch selection device, if backward travel is selected by the forward/backward switch device;

the shift control device sets the shift up permission vehicle speed to a second shift up permission vehicle speed that is greater than a first shift up permission vehicle speed, regardless of a height of the working machine device, and controls the transmission device so that a speed stage at the transmission is shifted up from speed 2 to speed 3 if the vehicle speed has continued to be equal to or greater than the second shift up permission vehicle speed for a backward travel setting time.

7. A shift control system for industrial vehicle according to claim 2, wherein:

speed stages at the transmission include 3 speeds or more;

the shift control device sets the shift up permission vehicle speed to a first shift up permission vehicle speed when the normal control has been selected by the shift up control switch selection device regardless of a height of the working machine device and setting of the forward/backward switch device, and controls the transmission device so as to shift up a speed stage at the transmission from speed 2 to speed 3 when the vehicle speed becomes equal to or greater than the first shift up permission vehicle speed.

8. A shift control system for industrial vehicle according to claim 3, wherein:

speed stages at the transmission include 3 speeds or more;

the shift control device sets the shift up permission vehicle speed to a first shift up permission vehicle speed when the normal control has been selected by the shift up control switch selection device regardless of a height of the working machine device and setting of the forward/backward switch device, and controls the transmission device so as to shift up a speed stage at the transmission from speed 2 to speed 3 when the vehicle speed becomes equal to or greater than the first shift up permission vehicle speed.

9. A shift control system for industrial vehicle according to claim 6, wherein:

speed stages at the transmission include 3 speeds or more;

the shift control device sets the shift up permission vehicle speed to a first shift up permission vehicle speed when the normal control has been selected by the shift up control switch selection device regardless of a height of the working machine device and setting of the forward/backward switch device, and controls the transmission device so as to shift up a speed stage at the transmission from speed 2 to speed 3 when the vehicle speed becomes equal to or greater than the first shift up permission vehicle speed.