JP2003287001A - Hydraulic motor operating circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an operating circuit for a hydraulic motor wherein cost is reduced by sharing a pilot pump for supplying pressure oil for a pilot to a hydraulic pilot valve and a charge pump for supplying pressure oil for a charge to a charge circuit, and further the cost is reduced by simplifying an oil passage. <P>SOLUTION: The hydraulic motor operating circuit is provided with the hydraulic motor M having the charge circuit 21 for supplying the pressure oil, a hydraulic negative brake B for providing braking force to the hydraulic motor M by operation by the hydraulic pilot valve V3, and a pilot circuit 20 for supplying the pressure oil for operation to the hydraulic pilot valve V3, and is so structured that the charge circuit 21 is branched off from the pilot circuit 20 to supply the pressure oil from the pilot circuit 20 to the hydraulic motor M. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic motor having a charge circuit for replenishing pressure oil, a hydraulic negative brake operated by a hydraulic pilot valve to apply a braking force to the hydraulic motor, and the hydraulic pressure. Type pilot valve and a pilot circuit for supplying pressure oil for operation to a hydraulic motor operation circuit.

[0002]

2. Description of the Related Art Such a hydraulic motor operating circuit is used, for example, to turn a backhoe turntable to the left or right. An operation circuit as shown in FIG. 3 is conventionally known. Was there. The conventional operation circuit shown in FIG. 3 is constituted by a turning hydraulic motor M having a charge circuit 21 for replenishing pressure oil, a brake disc 11 fixed to a drive shaft 10 of the hydraulic motor M, and a brake cylinder C5. Hydraulic negative brake B, and hydraulic pilot valve V for operating the negative brake B
3, the pilot circuit 20 for supplying pressure oil for operation to the pilot valve V3, the drain circuit 28, etc. are incorporated in the hydraulic motor block BL, and the charge circuit 21
The charging connection oil passage 30 is connected to. And
In the hydraulic motor block BL, two turning ports P1 and P2 for supplying pressure oil to the turning hydraulic motor M, and a brake port P for supplying pressure oil to the brake cylinder C5.
3, pilot port P4 for supplying pressure oil for pilot to hydraulic pilot valve V3, port P for drain
In addition to 5, the charging port P6 to the charging connection oil passage 30 is provided, the pilot port P4 is connected to the pilot pump, and the charging port P6 is connected to the charge pump.

[0003]

Therefore, in the conventional hydraulic motor operating circuit, in addition to the pilot pump for supplying the pilot pressure oil to the hydraulic pilot valve V3, the charging circuit 21 is supplied with the charging pressure oil. A charge pump was also needed. Further, when the hydraulic pilot valve V3 and the charge circuit 21 are incorporated in the hydraulic motor block BL, the pilot port P
In addition to 4, the charging port P6 is required, and the number of ports provided in the hydraulic motor block BL is increased, so that the oil passage connected to the port is complicated.

The present invention focuses on such a conventional problem, and an object thereof is to provide a pilot pump for supplying pilot pressure oil to a hydraulic pilot valve and a charge circuit for charging pressure oil. It can be shared with the supply charge pump to reduce costs and
An object of the present invention is to provide a hydraulic motor operating circuit capable of cost reduction by simplifying an oil passage.

[0005]

[Structure] The characteristic structure of the invention of claim 1 is that a hydraulic motor having a charge circuit for replenishing pressure oil and a braking force to be applied to the hydraulic motor by being operated by a hydraulic pilot valve. A hydraulic motor operating circuit comprising a hydraulic negative brake to be applied and a pilot circuit for supplying pressure oil for operation to the hydraulic pilot valve, wherein the charge circuit is branched from the pilot circuit. , Is configured to replenish the hydraulic motor with pressure oil from the pilot circuit.

[Operation / Effect] According to the characterizing feature of the invention of claim 1, the charge circuit for replenishing the hydraulic motor with the pressure oil is branched from the pilot circuit for supplying the pressure oil for operation to the hydraulic pilot valve. The hydraulic pump is configured to replenish the hydraulic motor with pressure oil from the pilot circuit, so that the pilot pump that supplies pressure oil for operation to the hydraulic pilot valve supplies pressure oil for charging to the charge circuit. The charge pump can also be used as a dual charge pump. This pilot pump can replenish the hydraulic motor with pressure oil only when operating hydraulic oil is supplied by supplying pressure oil for operation to the hydraulic pilot valve and releasing the braking force of the negative brake. Since the occurrence of cavitation that requires replenishing pressure oil for charging is mainly limited to the time when the hydraulic motor is operating, even if replenishing the pressure oil from the pilot pump, the cavitation phenomenon in the hydraulic motor can be achieved as desired. Can be avoided. Therefore, it is possible to reduce the cost by sharing the pump while preventing the occurrence of cavitation due to the hydraulic motor as in the conventional case.

[Structure] The characteristic structure of the invention of claim 2 is that the hydraulic motor, the charge circuit, the negative brake, and the hydraulic pilot valve and the pilot circuit are incorporated in a hydraulic motor block. It is in.

[Operation / Effect] According to the characterizing feature of the invention of claim 2, the hydraulic motor, the charge circuit, the negative brake, and the hydraulic pilot valve and the pilot circuit are incorporated in the hydraulic motor block. Therefore, it is not necessary to use a large number of pipes as an oil passage for connecting each element, the oil passage can be simplified, and the conventionally required charging port is not required. The oil passage connected to the work block is also simplified, and the cost can be further reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a hydraulic motor operating circuit according to the present invention will be described with reference to the drawings. Such a hydraulic motor operating circuit is used, for example, to turn a backhoe turning platform, and as shown in FIG. 1, a backhoe traveling platform 2 equipped with a pair of left and right crawler type traveling devices 1L and 1R. A swivel base 5 on which the engine 3 and the boarding operation unit 4 are mounted is mounted on the upper side so as to be fully swivel around the vertical axis X1. Boom 6, arm 7, and bucket 8 are sequentially connected to the front part of swivel base 5, and the front work is configured to be driven by hydraulic boom cylinder C1, arm cylinder C2, and bucket cylinder C3, respectively. The device uses the swing cylinder C4 to set the vertical axis X2.
It is equipped so as to be able to swing left and right around, and an excavation plate 9 for dozer work is provided at the front part of the traveling platform 2.

As shown in FIG. 2, the swivel base 5 is driven to swivel left and right by a swivel hydraulic motor M, and a brake disc 11 is fixed to a drive shaft 10 of the swivel hydraulic motor M, and A brake cylinder C5 that elastically applies a braking force to the disk 11 is provided, and a braking force is applied to the turning hydraulic motor M by a hydraulic negative brake B composed of the disk 11 and the brake cylinder C5. The turning hydraulic motor M and the negative brake B are incorporated in the hydraulic motor block BL. The turning hydraulic motor M has a neutral position N.
And a left turning position L and a right turning position R are controlled by a three-position switching type turning control valve V1. Therefore, a left turning operation connected to the output side of the turning control valve V1. The oil passage 12L is connected to the turning hydraulic motor M via the left turning port P1 of the hydraulic motor block BL, and the right turning operation oil passage 12R is connected to the turning hydraulic motor M via the right turning port P2. The turning control valve V1
It is configured to be operated by the pilot pressure from the operation pilot valve V2 via the pair of pilot oil passages 13 and 14.

The pilot pump PM2 for supplying the pilot pressure and the operating pump PM1 for supplying pressure oil to the turning hydraulic motor M are driven by the engine 3, and the operating pump PM1 has a swash plate angle change. A variable displacement pump whose discharge amount is changed is used, and its operating pump PM1 and the input side of the turning control valve V1 are connected by an operation oil passage 15, and the turning control valve V1 is drained. The path 16 is also connected. Pilot pump PM2
Is a constant-capacity gear pump, the pilot pump PM2 and the operating pilot valve V2 are connected by a pilot pressure supply passage 17, and the operating pilot valve V2 is also connected to an oil discharge passage 18. By operating the operation pilot valve V2 by the operation lever 19 provided in the control tower of the boarding operation unit 4, the pilot pressure from the pilot pump PM2 is changed to the pair of pilot oil passages 1.
It is configured such that it can be switched between a state in which it is supplied to any one of 3 and 14 and a state in which it is not supplied to any of the pilot oil passages 13 and 14.

The brake cylinder C5 of the negative brake B is operated by a hydraulic pilot valve V3, so that the hydraulic pilot valve V3 is a pilot oil serving as a pilot circuit for supplying pressure oil for operation to the pilot valve V3. A passage 20 is provided, and the pilot oil passage 20 and the hydraulic pilot valve V3 are also incorporated in the hydraulic motor block BL. The turning hydraulic motor M has a charge circuit 21 for replenishing the motor M with pressure oil, and specifically, includes a one-way valve 22L and is connected to the left turning operation oil passage 12L. Charge oil passage 21L and a right-turning charge oil passage 21R connected to the right-turning operation oil passage 12R with a one-way valve 22R. The connected oil passage 23 is connected to the pilot oil passage 20.
It is connected to the. In other words, the charge circuit 21
It is configured to be branched from the pilot oil passage 20 via the connection oil passage 23 so as to replenish the turning hydraulic motor M with the pressure oil from the pilot oil passage 20, and the charge circuit 21 and the connection oil passage 23 also. It is incorporated in the hydraulic motor block BL.

A brake oil passage 24 for supplying pressure oil to the brake cylinder C5 of the negative brake B via the hydraulic pilot valve V3 is also incorporated in the hydraulic motor block BL, and the brake port P3 thereof is
A brake pump PM3 driven by the engine 3 is connected. A connecting oil passage 25 is connected to the pilot port P4 of the pilot oil passage 20, and the connecting oil passage 25 is connected to the pair of pilot oil passages 26 and 27 via the shuttle valve V4, and one pilot oil passage Road 2
6 in the pilot oil passage 13 to the turning control valve V1,
The other pilot oil passages 27 are respectively connected to the pilot oil passages 14 to the turning control valve V1. Then, in the hydraulic motor block BL, a drain circuit 28 for collecting drain oil from the hydraulic pilot valve V3, the brake cylinder C5, and the turning hydraulic motor M.
A drain oil passage 29 is connected to the drain port P5.

Next, the operation of this hydraulic motor operating circuit will be described. To turn the turning base 5, the operating pilot valve V2 is operated by the operating lever 19 of the boarding operation unit 4, and the pilot pump PM2 is operated. The turning control valve V1 is switched to the left turning position L or the right turning position R by the pilot pressure oil. Then, the pressure oil from the operation pump PM1 is supplied to the left turning operation oil passage 12L.
Alternatively, the oil is supplied to the turning hydraulic motor M through the right turning operation oil passage 12R, and at the same time, the pair of pilot oil passages 1
The pressure oil from any one of 3 and 14 is supplied to the hydraulic pilot valve V3 via the shuttle valve V4, the connecting oil passage 25, the pilot port P4, and the pilot oil passage 20, so that the pilot valve V3 becomes It is moved to the right as shown in FIG. As a result, the pressure oil from the brake pump PM3 is supplied to the cylinder chamber of the brake cylinder C5 in the negative brake B,
The cylinder rod is moved against the elastic force of the elastic member installed in the cylinder C5 to release the braking force, and the swivel base 5 is swung left or right.

While the swivel base 5 is turning, the oil pressure from either one of the pair of pilot oil passages 13 and 14 acts on the pilot oil passage 20, so that the oil pressure is charged via the connecting oil passage 23. It also acts on the circuit 21, for example
When cavitation occurs in the turning hydraulic motor M while the turning base 5 is turning to the left, the pilot oil passage 20
The pressure oil from is replenished to the turning hydraulic motor M via the one-way valve 22L and the left turning charge oil passage 21L, and the hollow phenomenon is avoided. Then, by operating the operation pilot valve V2 with the operation lever 19 to switch the turning control valve V1 to the neutral position N, the supply of the pressure oil to the turning hydraulic motor M is stopped, and at the same time, the pilot valve V1 is stopped. V3 returns to the left side, and the braking force acts on the turning hydraulic motor M again by the elastic force of the elastic member provided in the brake cylinder C5, so that the turning base 5 stops at the desired position.

[Other Embodiment] (1) In the above embodiment, the turning hydraulic motor M, the negative brake B, the hydraulic pilot valve V3, the pilot oil passage 20, the charge circuit 21, and the like are used as a hydraulic motor block. Although the configuration incorporated in the BL is shown, this hydraulic motor block BL does not necessarily mean a single block, but also includes a block configured by connecting a plurality of blocks to each other. Further, the hydraulic motor block BL is not always essential, and it can be implemented without incorporating the negative brake B, the hydraulic pilot valve V3, and the like into the hydraulic motor block BL.

(2) In the previous embodiment, the configuration was described in which the hydraulic motor operating circuit according to the present invention swivels the backhoe swivel base 5. This hydraulic motor operating circuit swivels the backhoe swivel base 5. It can be applied to various hydraulic motor operations including, for example, traveling machines for various construction machines and agricultural work machines, etc., and the hydraulic motor is not limited to those that rotate in the forward and reverse directions. It can also be applied to a hydraulic motor that rotates only in the forward direction.

[Brief description of drawings]

1] Overall side view of backhoe

[Fig. 2] Hydraulic motor operation circuit diagram

[Fig. 3] Conventional hydraulic motor operation circuit diagram

[Explanation of symbols]

20 Pilot circuit 21 Charge circuit B Negative brake BL hydraulic motor block M hydraulic motor V3 hydraulic pilot valve

Claims (2)

[Claims] 1. A hydraulic motor having a charge circuit for replenishing pressure oil, a hydraulic negative brake operated by a hydraulic pilot valve to apply a braking force to the hydraulic motor, and a hydraulic pilot valve for operation. And a pilot circuit for supplying pressure oil, wherein the charge circuit is branched from the pilot circuit to replenish the hydraulic motor with pressure oil from the pilot circuit. Hydraulic motor operating circuit configured. 2. The hydraulic motor operation circuit according to claim 1, wherein the hydraulic motor and charge circuit, the negative brake, and the hydraulic pilot valve and pilot circuit are incorporated in a hydraulic motor block.