JPH0790804B2 - Idling wheel support device for crawler type traveling device - Google Patents

Description

The present invention relates to an idle wheel support device in a crawler type traveling device used as a traveling device such as a bulldozer.

[Conventional technology]

The running resistance of the crawler type traveling device is as shown in Fig. 3,
It has a close relationship with the tension of the crawler belt, and there is an optimum tension depending on each traveling speed, and a curve a in the figure is a connection of the optimum tension at each speed.

By the way, in a conventional idler wheel support device in a crawler type traveling device, grease is filled with grease or the like in a cylinder of an elastic support portion by a spring, and a preload is applied by the filling pressure of the grease so that the crawler belt has a degree of tension. Has become.

[Problems to be solved by the invention]

In the conventional idle wheel support device, since the grease pressure in the cylinder is constant regardless of the traveling speed, it is not possible to obtain the degree of tension of the crawler belt that optimizes the traveling resistance for all vehicle speeds.

[Means and Actions for Solving Problems]

The present invention has been made in view of the above, and the tension of the crawler belt by the idler wheel support device can be optimally set for each vehicle speed according to the vehicle speed, whereby the running resistance at each vehicle speed is obtained. It is intended to provide an idler wheel supporting device in a crawler type traveling device which can minimize the fuel consumption of the engine and reduce the fuel consumption of the engine. In the idler wheel support device of the crawler track type traveling device that supports through the grease enclosed in the grease chamber, a grease supply device that is composed of a cylinder and a piston and that operates with the oil pressure acting on the piston in the cylinder is provided in the grease chamber. Connect to the pressure oil supply section of this grease supply device, connect the hydraulic pump via the electromagnetic switching valve, and connect the electromagnetic variable relief valve. The electromagnetic switching valve and the electromagnetic variable relief valve are connected to a controller that outputs an operation signal corresponding to the vehicle speed signal to each electromagnetic operation portion. The variable relief valve operates according to the vehicle speed, the grease pressure in the grease chamber of the idler wheel support device changes according to the vehicle speed, and the tension of the crawler belt is optimally set according to the vehicle speed.

〔Example〕

 An embodiment of the present invention will be described with reference to the drawings.

In the figure, reference numeral 1 designates an idle wheel supported by a front end portion of a track frame 2 via a bearing 3 movable in the front-rear direction, and reference numeral 4 designates a crawler belt wound around the idle wheel 1 and an activation wheel (not shown). Reference numeral 5 is an idler wheel supporting device for biasing the bearing 3 of the idler wheel 1 forward to give tension to the crawler belt 4. The idler wheel supporting device 5 is supported by the track frame 2. The idler wheel support device 5 comprises a rod 6 connected to the bearing 3, a spring chamber 8 connected to the rod 6 via a grease chamber 7, and a spring 9 for biasing the spring bearing 8 forward. The spring 9 buffers the impact force acting on the idler wheel 1, and the degree of tension of the crawler belt is adjusted by the amount of grease filled in the grease chamber 7.

The grease chamber 7 is connected to the grease supply device 10. The grease supply device 10 includes a cylinder 11 including a piston 11 having a small diameter portion 11a and a large diameter portion 11b, a small diameter chamber 12a into which the small diameter portion 11a is fitted, and a large diameter chamber 12b into which the large diameter portion 11b is fitted. The grease is injected into the small diameter portion 12a, and the small diameter chamber 12a is inserted into the grease chamber 7a.
Is in communication with. A hydraulic pressure supply circuit 13 is connected to the large diameter chamber 12b.

The hydraulic pressure supply circuit 13 includes a hydraulic pump 14, an electromagnetic switching valve 15 having a shutoff position 15a and a connection position 15b, a pilot check valve 16, and an electromagnetic variable relief valve 17. The electromagnetic operation portions 15c and 17a of the electromagnetic switching valve 15 and the electromagnetic variable relief valve 17 are connected to the controller 18. The controller 18 is connected to the vehicle speed signal output device 19 and the respective signal generators of the pressure sensor 20 that detects the pressure in the grease chamber 7.

The controller 18 operates as shown in the flowchart of FIG.

That is, the vehicle speed signal v from the vehicle speed signal output device 19 is read, and the optimum tension is calculated based on this vehicle speed signal. This optimum tension calculation calculates the optimum grease chamber pressure Pl _O according to the vehicle speed and the pressure P in the large diameter chamber 12b of the grease supply device 10.
Calculate _CO . Then, the pressure P _S is read from the pressure sensor 20, the pressure value filtering process is performed based on this value, and the current pressure value P _SO is calculated.

Compare this P _SO and grease chamber pressure optimum value Pl _O, P _SO is, Pl _O
Solenoid switching valve 15 and solenoid variable relief valve when lower
An actuation signal is output to each of the electromagnetic actuating portions 15c and 17a of 17 so that the electromagnetic switching valve 15 is in the connection position 15b, and the pressure oil passes through the pilot check valve 16 and the large diameter chamber of the grease supply device 10
Supplied to 12b. At the same time, the electromagnetic variable relief valve 17 is set to a predetermined relief pressure so that the pressure in the large diameter chamber 12b of the grease supply device 10 becomes a predetermined working pressure, whereby the piston 11 is operated and the grease in the small diameter chamber 12a is activated. Is supplied to the grease chamber 7 of the idle wheel support device 5, and the pressure in the grease chamber 7 becomes a pressure Pl _O suitable for the vehicle speed.

When the pressures Pl _O and P _SO reach a predetermined pressure, the calculation of the controller 18 ends, the signal to each electromagnetic actuation unit becomes zero, and the electromagnetic switching valve 15 becomes the shutoff position 15a. At this time, although the relief pressure of the electromagnetic relief valve 17 becomes low, the grease supply device 10 is stationary because the pilot check valve is interposed.

〔The invention's effect〕

According to the present invention, the tension of the crawler belt 4 by the idle wheel support device 5 can be optimally set for each vehicle speed in accordance with the vehicle speed, so that the running resistance at each vehicle speed can be minimized. As a result, wear of the crawler type traveling device is reduced, repair costs can be reduced, and fuel consumption of the engine can be reduced by reducing traveling resistance.

[Brief description of drawings]

FIG. 1 is a configuration explanatory view showing an essential part of the present invention, FIG. 2 is a flow chart showing an operation of a controller, and FIG. 3 is a diagram showing running resistance with respect to tension of a crawler belt at different vehicle speeds. 1 is an idler wheel, 3 is a bearing, 7 is a grease chamber, 9 is a spring, 10
Is a grease supply device, 11 is a piston, 12 is a cylinder, 14
Is a hydraulic piston, 15 is an electromagnetic switching valve, 17 is an electromagnetic variable relief valve, 15c and 17a are electromagnetic operating parts, and 18 is a controller.

Claims (1)

[Claims] 1. A floating wheel supporting device in a crawler type traveling device, which supports a bearing 3 supporting an idler wheel 1 through a spring 9 and a grease filled in a grease chamber 7, wherein a cylinder 12 and a piston are provided in the grease chamber 7. Consisting of 11 and piston
11 is connected to a grease supply device 10 that operates by hydraulic pressure acting on a cylinder 12, a hydraulic pump 14 is connected to the cylinder 12 of the grease supply device 10 via an electromagnetic switching valve 15, and an electromagnetic variable relief valve is connected. 17 are connected to each of the electromagnetic switching parts 15 and the electromagnetic variable relief valves 17 of the above-mentioned electromagnetic operation parts 15
An idle wheel support device in a crawler type traveling device, characterized in that a controller 18 for outputting an actuation signal corresponding to a vehicle speed signal to both electromagnetic actuating parts 15c, 17a is connected to c, 17a.