JPH04108649U - bulldozer hydraulic system - Google Patents

Abstract

(57) [Summary] [Purpose] To avoid shortening the life of the oil cooler of a bulldozer equipped with an impact ripper device and an oil cooler in the hydraulic circuit. [Structure] The oil in the oil tank 1 is pumped through the operating valves 3, 4, 5, 6, and 7 by the hydraulic pump 2 to the hydraulic cylinder 1 for the work machine.
0, 11, 12, 13 and the hydraulic circuit of the bulldozer, the return oil of the hydraulic cylinder and the oil relieved from the relief valve 15 are cooled through the oil cooler 16 in the circuit 21, thereby maintaining the heat balance of the entire circuit. The oil returned from the hydraulic breaker 14 is returned to the oil tank 1 via the oil filter 17 in the circuit 22 without passing through the oil cooler. [Effect] The return oil of the hydraulic breaker is affected by hydraulic pulsation,
Although pulsation occurs on the low pressure side and peak pressure occurs, the return oil does not pass through the oil cooler, so the service life does not decrease.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention relates to the hydraulic system of bulldozers, especially for bulldozers equipped with impact rippers. Regarding the hydraulic system.

0002

[Conventional technology]

Figure 2 shows a conventional bulldozer working machine hydraulic circuit, where 1 is an oil tank; 2 is a hydraulic pump, 3 is a hydraulic breaker operating valve, and 4 is a blade lift system. A blade lift operation valve that controls the cylinder 10, 5 is a ripper operation valve, 6 is a circuit switching between the ripper lift cylinder 11 and the ripper tilt cylinder 12. 7 is a switching valve that controls the blade tilt cylinder 13. 14 is a hydraulic breaker, and 15 is a hydraulic breaker circuit release. 16 is an oil cooler, and 17 is an oil filter.

0002 The pressure oil discharged from the hydraulic pump 2 can be used to operate each operating valve as necessary. is sent to each cylinder to perform the necessary work. Return from cylinder The oil passes through the circuit 23, passes through the oil filter 17, and is returned to the oil tank 1. . When operating the hydraulic breaker 14, the hydraulic breaker is operated from the hydraulic breaker operation valve 3. Send oil to engine 14. The returned oil and the oil relieved from the relief valve 15 are The oil is sent to the oil filter 16 to be cooled, and then passes through the oil filter 17 to the oil tank 1. be returned. In other words, the heat balance of the entire circuit is maintained by cooling a portion of the total flow. Ru.

0003

[Problem that the idea aims to solve]

According to the above configuration, the return oil from the hydraulic breaker is passed through the oil cooler. are doing. However, the hydraulic pulsation of the hydraulic breaker affects the low pressure return oil. Pulsation also occurs and peak pressure occurs, reducing the lifespan of the oil cooler.

0004 This invention was developed focusing on the above problem, and it reduces the lifespan of the oil cooler. The purpose is to provide a bulldozer hydraulic system that does not cause damage.

[0005]

[Means to solve the problem]

In order to achieve the above purpose, the hydraulic system of the bulldozer according to the present invention uses hydraulic pressure. A full dozer work machine equipped with an impact ripper that impacts the shank with a breaker. In hydraulic equipment equipped with an oil cooler in the hydraulic circuit for A circuit that connects the return side of the cylinder and the oil tank via an oil cooler, and A circuit that connects the return side of the pressure breaker and the oil tank without going through the oil cooler. It is characterized by having a road.

[0006]

[Effect]

According to the above configuration, the return side of the hydraulic breaker does not go through the oil cooler, so The oil cooler is not affected by hydraulic pulsations. In addition, work machine hydraulic cylinder Since the returned oil goes through the oil cooler, the overall heat balance is maintained.

[0007]

【Example】

Examples of the hydraulic system for a bulldozer according to the present invention will be described below with reference to the drawings. explain. Figure 1 is a hydraulic circuit diagram of the hydraulic system of the present invention, and shows the oil cooler circuit and other parts. The names, relative positions, and functions of the parts are otherwise the same as the conventional one, so explanations are omitted. Only the different parts will be explained. Return circuit 21 and return circuit from hydraulic cylinder for work equipment The oil relieved from the leaf valve 15 passes through the oil cooler 16 and passes through the oil filter. 17 and is returned to the oil tank 1. The return oil of the hydraulic breaker 14 is sent to the circuit 22. The oil is then returned to the oil tank 1 via an oil filter 17. Therefore, the oil cooler Peak pressure due to hydraulic pulsation is not applied to the rubber 16. Also, the return from the hydraulic cylinder By passing the oil through the oil cooler 16, a part of the flow is cooled and the entire circuit is heated. I try to maintain a balance.

[0008]

[Effect of the idea] As mentioned above, in this invention, the return oil of the hydraulic cylinder passes through the oil cooler, and The oil returned from the oil cooler is returned directly to the oil tank without passing through the oil cooler. Therefore, the oil cooler is not affected by hydraulic pulsations and therefore has a long service life. Wear. Also, the beat balance of the entire circuit is to cool the return oil of the hydraulic sitanda. It can be kept in

[Brief explanation of drawings]

FIG. 1 is a hydraulic circuit diagram of a hydraulic system for a bulldozer according to the present invention.

FIG. 2 is a hydraulic circuit diagram of a conventional bulldozer hydraulic system.

[Explanation of symbols]

1 Oil tank 2 Hydraulic pump 3 Hydraulic breaker operation valve 14 Hydraulic breaker 15 Relief valve 16 Oil cooler 17 Oil filter 21, 22 circuit

Claims (1)

[Scope of utility model registration request] Claim 1: In a hydraulic system equipped with an oil cooler in the hydraulic circuit for a working machine of a bulldozer equipped with an impact ripper that applies an impact to the shank with a hydraulic breaker, the return side of a hydraulic cylinder for operating the working machine and an oil tank. A hydraulic system for a bulldozer, comprising a circuit that connects the return side of the hydraulic breaker and an oil tank without going through the oil cooler.