CN204646822U - A kind of hydraulic control system for loader - Google Patents

Abstract

The utility model discloses a hydraulic control system for a loader, which comprises a gear pump 1 and a filling valve group 3. The oil outlet of the gear pump 1 is connected to the filling valve group 3 through an oil filter 2, and the filling valve The oil circuit from group 3 is divided into N oil circuit and M oil circuit. The M oil circuit controls the brake cylinder 5 through the electromagnetic reversing valve. The hydraulic oil is respectively connected to the accumulator 4 and the alarm switch 7 at the oil inlet of the electromagnetic reversing valve. The parking brake and brake release of the brake cylinder are realized by controlling the electromagnetic reversing valve, and the parking brake is no longer realized by means of air top oil; at the same time, the pilot steering oil circuit and the pilot control oil circuit are provided by the pressure reducing valve. Hydraulic oil, the oil circuit system is stable in operation and compact in structure.

Description

A hydraulic control system for loader

technical field

The utility model relates to the field of loader equipment, specifically a hydraulic control system for a loader.

Background technique

At present, the parking brake of the loader is the same as the service brake, and the parking brake is completed by the air top oil method. This kind of air top oil method has a large air compressibility and a long feedback time, resulting in slow braking response and The braking effect is not good, and the phenomenon of insufficient pressure is easy to occur, which affects the reliability of the system; at the same time, the pressure oil circuit system required by other executive units, such as the steering system and the operating system, is complex and the oil circuit layout is messy, which is not conducive to the installation of the oil circuit Laying and subsequent maintenance.

Contents of the invention

In order to solve the above-mentioned technical problems, the utility model provides a hydraulic control system for a loader, which realizes the parking brake and brake release of the brake cylinder by controlling the electromagnetic reversing valve, and no longer passes the gas cap oil The parking brake is realized by the way; at the same time, hydraulic oil is provided for the pilot steering oil circuit and the pilot control oil circuit through the pressure reducing valve. The oil circuit system is stable in operation and compact in structure.

In order to achieve the above object, the technical solution adopted in the utility model is:

Including the gear pump and the charging valve group, the oil outlet of the gear pump is connected to the charging valve group through the oil filter, the oil circuit from the charging valve group is divided into N oil circuit and M oil circuit, and the M oil circuit is replaced by an electromagnetic switch. The directional valve controls the brake cylinder, and the N oil circuit provides hydraulic oil for the steering system and the operating system through the pressure reducing valve and the overflow valve, and the oil inlet of the electromagnetic directional valve is respectively connected to the accumulator and the alarm switch.

When the parking brake is required, the pressure oil in the brake cylinder is removed by controlling the electromagnetic reversing valve, and the brake cylinder realizes the parking brake through the spring force; when the brake needs to be released, the electromagnetic reversing valve is controlled again to The brake cylinder provides pressure oil, and the pressure oil compresses the spring to release the brake. Due to the design of the accumulator and the alarm switch, the pressure oil flows into the accumulator in advance to provide a stable pressure for the release of the brake. At the same time, the alarm switch implements low pressure alarm. , when the pressure of the accumulator is lower than the set pressure of 15Mpa, the filling valve group opens to fill the accumulator again; the N oil circuit of the system provides hydraulic oil for the actuator, which meets the operating pressure oil required by the actuator , improve the utilization rate of the gear pump and avoid the waste of pressure oil.

The utility model is designed that the electromagnetic reversing valve is set as a two-position four-way electromagnetic reversing valve, the pressure reducing valve is set as a pilot type pressure reducing valve, and the overflow valve is set as a pilot type overflow valve. The control oil ports of the pilot-operated pressure reducing valve and the pilot-operated relief valve are respectively connected to the oil return port of the two-position four-way electromagnetic reversing valve 8.

The utility model is designed, the pressure upper limit of the overflow valve control system is 16Mpa, and the lower limit of the liquid filling pressure of the accumulator is set by the spring value of the two-position three-way variable reversing valve in the liquid filling valve group Set the low pressure alarm value of the accumulator filling pressure to 12Mpa through the alarm switch, and set the oil outlet pressure of the pilot pressure reducing valve to 3Mpa.

Description of drawings

Fig. 1 is the schematic diagram of the oil circuit of the utility model.

Detailed ways

The utility model is described in detail below in conjunction with accompanying drawing and specific embodiment:

As shown in Figure 1, it is a specific embodiment of the utility model. The hydraulic control system for loaders includes a gear pump 1 and a filling valve group 3. Liquid valve group 3, filling valve group 3 is composed of a two-position three-way variable directional valve and a three-position two-way hydraulic control directional valve, which can be set by setting the spring value of the two-position three-way variable directional valve Change the oil outlet pressure value of the filling valve group 3. The oil circuit from the filling valve group 3 is divided into N oil circuit and M oil circuit. For pressure oil, an accumulator 4 and an alarm switch 7 are respectively set between the check valve and the oil outlet of the two-position four-way electromagnetic reversing valve 8, and the built-in relief valve and the two-position three-way The upper and lower limits of the pressure value of the variable reversing valve ensure that the pressure oil of the accumulator 4 is stable within a certain value range, and one working port of the two-position four-way electromagnetic reversing valve 8 is connected to the brake cylinder 5 and the other. One working oil port can be blocked or reserved first. When the two-position four-way electromagnetic reversing valve 8 is powered off, as shown in Figure 1, the pressure oil in the brake cylinder 5 is in a depressurized state at this time, which is realized by spring force. Parking brake; when the two-position four-way electromagnetic reversing valve 8 is energized, the valve core moves to the right and fills the brake cylinder 5 with oil, and the oil pressure in the cylinder overcomes the spring force, thereby releasing the parking brake; N The oil circuit is connected to the pilot relief valve 9 through the pilot relief valve 10, and the control oil ports of the pilot relief valve 10 and the pilot relief valve 9 are respectively connected to the oil return port of the two-position four-way electromagnetic reversing valve 8. Finally, the pressure oil from the pilot pressure reducing valve 9 provides pressure oil for the pilot steering system and the pilot control system respectively,

In this example, the hydraulic oil from the filling valve group 3 can lead to a reserved port B2, which can provide pressure oil for service braking,

In this example, the upper limit of the system pressure is controlled by the relief valve inside the gear pump 1 to 16Mpa, and the charge of the accumulator 4 is controlled by the spring value of the two-position three-way variable reversing valve in the filling valve group 3. The lower limit of the hydraulic pressure is set to 15Mpa, the low pressure alarm value of the liquid filling pressure of the accumulator 4 is set to 12Mpa through the alarm switch 7, and the oil outlet pressure of the pilot pressure reducing valve 9 is set to 3 Mpa.

The technical effect of the utility model is:

1. Due to the design of the gear pump 1 (built-in relief valve type), the liquid filling valve group 3, the electromagnetic reversing valve to control the brake cylinder 5, the energy storage 4 and the alarm switch 7, by controlling the connection of the electromagnetic reversing valve The release and start of the parking brake are realized through power failure and power failure. At the same time, the pressure oil in a certain range is stored through the accumulator 4, which ensures the release of parking and the parking brake of the brake cylinder 5, and no longer passes through the gas cap oil. The parking brake is realized by the method, and the control is convenient and the operation is reliable.

2. Due to the design of the built-in overflow valve type gear pump 1, the liquid filling valve group 3, the alarm switch 7, and the accumulator 4, it is ensured that the pressure oil in the accumulator 4 is within a certain value range, and it is the brake cylinder. The operation of 5 provides reliable pressure oil and improves the safety of the system.

3. Due to the design of the N oil circuit to provide hydraulic oil for the pilot steering system and the pilot control system through the pressure reducing valve and the overflow valve, the utilization rate of the pressure oil pumped by the gear pump 1 is improved, and the waste of pressure oil is avoided.

Of course, the above description is not a limitation of the present utility model, and the present utility model is not limited to the above-mentioned examples, and changes, modifications, additions or replacements made by those skilled in the art within the essential scope of the present utility model are also acceptable. Should belong to the protection scope of the utility model.

Claims (3)

1. A hydraulic control system for a loader, characterized in that it includes a gear pump (1) with a built-in relief valve (11) and a filling valve group (3), and the oil outlet of the gear pump (1) is connected to The oil filter (2) is connected to the filling valve group (3). The oil circuit from the filling valve group (3) is divided into N oil circuit and M oil circuit. The M oil circuit controls the brake cylinder ( 5), the N oil circuit provides hydraulic oil for the pilot steering system and the pilot control system through the pressure reducing valve and the overflow valve, and the oil inlet of the electromagnetic reversing valve is respectively connected to the accumulator (4) and the alarm switch (7) . 2. A hydraulic control system for a loader according to claim 1, characterized in that: the electromagnetic reversing valve is set as a two-position four-way electromagnetic reversing valve (8), and the pressure reducing valve is set It is a pilot-operated pressure reducing valve (9), and the relief valve is set as a pilot-operated relief valve (10), and the control oil ports of the pilot-operated pressure-reducing valve (9) and the pilot-operated relief valve (10) are respectively Connect to the oil return port of the two-position four-way solenoid valve (8). 3. A hydraulic control system for a loader according to claim 2, characterized in that: the pressure upper limit of the overflow valve (11) control system is 16Mpa, through the two valves in the filling valve group (3) Set the lower limit of the liquid filling pressure of the accumulator (4) to 15Mpa for the spring value of the three-way variable reversing valve, and alarm the low pressure of the liquid filling pressure of the accumulator (4) through the alarm switch (7). Set the value to 12Mpa, and set the outlet pressure of the pilot pressure reducing valve (9) to 3 Mpa.