JP5523980B2 - Hydraulic motor with slip suppression and startup efficiency improvement functions - Google Patents

Description

  The present invention relates to a hydraulic motor, and more particularly to slip suppression and startup efficiency in a hydraulic motor mounted on a construction machine such as a hydraulic excavator.

  As the above-described hydraulic motor, as shown in Patent Document 1, a cylinder block is rotatably provided with a shaft in a housing, and a piston is fitted into a cylinder hole of the cylinder block to constitute a cylinder chamber. A variable piston motor is known in which a cylinder block rotates with a shaft by making the cylinder chamber slidable along a swash plate and alternately communicating the cylinder chamber with a hydraulic pressure source and a tank.

  As a brake device of the hydraulic motor, a rotation side friction plate and a fixed side friction plate are alternately attached to a cylinder block and a housing, a piston is provided opposite to the friction plate, and this piston is pushed by a spring to rotate with the fixed side friction plate. The cylinder block is fixed and braked by crimping the side friction plate, and the piston is moved against the spring by supplying high pressure oil to the piston pressure receiving chamber of the piston, and the fixed side friction plate and the rotation side friction plate are moved. The cylinder block can be rotated apart and is in a non-braking state.

  Such a brake device of a hydraulic motor is not braked when high pressure oil is supplied to the piston pressure receiving chamber, and is braked when high pressure oil is discharged from the piston pressure receiving chamber.

  By the way, when the above-described hydraulic motor is used as a swinging or traveling motor for a construction machine, in operation, that is, in a non-braking state, the supply of pressure oil to the hydraulic motor is stopped by a switching valve and Even when traveling is stopped, it may be necessary for the construction machine to maintain a state in which its posture is inclined, for example, on an inclined ground. In such a state, which is not intended by the operator, the swivel mounted with the boom and arm is affected by gravity, and a rotational load is applied to the hydraulic motor shaft. There is a problem in that the outlet side becomes high pressure and leakage occurs through the clearance of the valve plate, so that its posture gradually changes or the stop position gradually changes. In order to prevent such problems, a small piston is provided in the valve plate, and the generated high pressure is used to press the valve plate against the end face of the cylinder block to prevent unintentional changes in posture and position due to gravity. ing. Details will be described with reference to FIGS.

  FIG. 2 is a longitudinal sectional view in the front axial direction along the axial direction of a conventional hydraulic motor adopted by the applicant of the present application, and FIG. 3 is a longitudinal sectional view perpendicular to the section in FIG. 4A and 4B are views showing the shape of the valve plate, where FIG. 4A is a front view and FIG. 4B is a cross-sectional view taken along the line z-z in FIG.

  In FIG. 2, reference numeral 10 denotes a hydraulic motor housing. The housing 10 is provided with a cylinder block 16 rotatably supported by a cylindrical roller bearing 12 and a needle bearing 14 and an output shaft 18 integral therewith. Yes. A plurality of equally spaced cylinders are provided on the circumference inside the cylinder block 16, and a piston PS is slidably accommodated in each cylinder. The head of the left end of the piston PS is engaged with an annular retainer 20 so that the left end surface of the retainer 20 slides on the swash plate 22.

  Reference numeral BP denotes a valve plate whose left end surface is in contact with the right end surface of the cylinder block 16, and whose right end surface is in contact with the left end surface of the motor cover 30 fastened to the housing 10. The motor cover 30 is provided with a port for supplying and discharging pressure oil. Reference numeral 40 is a brake of a hydraulic motor generally referred to as a parking brake, and includes a stationary friction plate and a rotation friction plate 40b paired with a piston 40a, a spring 40c, and an inner peripheral surface of the housing 10. And a pressure oil supply cylinder 40d formed between the two. When pressure oil, for example, pilot pressure oil for a construction machine, is applied to the pressure oil supply cylinder 40d, the piston 40a moves to the right and compresses the spring 40c that has pressed the fixed-side friction plate and the rotation-side friction plate 40b until then. At the same time, the fixed friction plate and the rotation side friction plate 40b are separated. As a result, the cylinder block 16 can rotate.

  On the other hand, when the supply of the pilot pressure is released, the piston 40a goes to the left, the spring 40c is released, and the fixed side friction plate and the rotation side friction plate 40b are pressed tightly by the elastic force of the spring 40c, resulting in the cylinder. The block 16 is integrated with the housing 10 and is prevented from rotating. That is, even when the engine of the construction machine is stopped and the main pump and the pilot pump (not shown) are stopped, the rotation is prevented.

  A small piston SPS is provided inside the valve plate BP. As shown in FIG. 4B, a plurality of (two) cylinders 30a are provided on the motor cover 30 side of the small piston SPS, and the small piston SPS is accommodated therein. Reference numeral 50 is a partially formed annular groove, and a pair is formed vertically as shown in FIG. Reference numerals 50a and 50b are ports for supplying and discharging the pressure oil, and the pressure oil is exchanged with the oil chamber HR in which each piston PS in the cylinder block 16 is accommodated within the range of the angular positions of these ports. In FIG. 4A, if one of the ports 50a and 50b is for discharge, the other is for supply, and both ports have both functions. Here, for the sake of explanation, the port 50a will be described as discharging and the port 50b will be described as supplying.

  In FIG. 3, reference numerals 60a and 60b are bushes and flat springs, and are set so that the sliding surfaces of the valve plate BP and the cylinder block 16 have an appropriate oil film thickness. Reference symbol RF is a relief valve.

  Now, the main pump and the pilot pump of the construction machine are in the drive state, but when the rotation of the hydraulic motor for driving the swivel is stopped, that is, in the state where the pressure oil is not supplied / discharged, it is described above. As described above, if the construction machine is located on the inclined surface, a rotation load may act on the output shaft 18 of the hydraulic motor to rotate the cylinder block 16. Due to this action, the piston PS located on the discharge side tries to discharge the oil in the oil chamber HR through the port 50a, but the outlet is blocked, so that the pressure is applied from the groove 50 to the flow path 30b (FIG. 4). Acting on the small piston SPS via (b). Therefore, the right end surface of the piston SPS presses the motor cover 30 with the force F. On the other hand, since the motor cover 30 is fixed to the housing 10, the valve plate BP is eventually pressed against the right end surface of the cylinder block 16 by the reaction force F, and the rotation of the cylinder block 16, that is, slippage is prevented by frictional force or the like. To do.

Japanese Patent Laid-Open No. 08-177899

  In the above-described prior art, a static friction force is generated between the valve plate BP and the cylinder block 16 using the pressure oil discharged from the small piston, thereby preventing the rotation of the turning hydraulic motor, that is, slipping. However, when the hydraulic motor is switched from the stopped state to the driven state, the blocking state is maintained. Therefore, when the hydraulic motor is started, a pressure higher than that is applied to the valve plate BP so that the right end surface of the cylinder block 16 is subjected to dynamic friction. It is necessary to slip in the state. Since such switching from stop to start frequently occurs during a series of work of the construction machine, the energy for the start force required every time is not negligible in the work on the slope.

  The present invention is intended to solve the above problems, and an object of the present invention is to provide a hydraulic motor capable of achieving both suppression of slip at the time of stop and improvement of start efficiency at the time of start. .

  In order to achieve the above object, a hydraulic motor having slip suppression and start-up efficiency improvement functions according to the present invention is provided with a cylinder block in a housing so as to be rotatable integrally with an output shaft, and a plurality of cylinders formed in the cylinder block. Pistons are respectively inserted into the holes to form cylinder chambers, the pistons are slidable along the swash plate, and the cylinder chambers are alternately communicated with a hydraulic pressure source and a tank so that the cylinder block is connected to the output shaft. A rotating fixed displacement or variable displacement piston motor, one side of which is in contact with the end face of the cylinder block opposite to the output shaft, and an opening for alternately communicating the cylinder chamber with a hydraulic pressure source and a tank. A motor plate having a pressure oil supply / discharge port that is in contact with the other side surface of the valve plate and fixed to the end surface of the housing. And a pressing means provided between the motor cover and the valve plate for pressing the valve plate against the cylinder block end face with a predetermined spring force, and between the outer periphery of the cylinder block and the motor cover in the housing. First brake means for parking brake provided and second brake means for pressing the other side surface of the valve plate with a predetermined hydraulic pressure, the second brake means facing the other side surface of the valve plate and A plurality of oil chambers provided on the motor cover side, a small piston housed in each oil chamber, a small piston pressurizing port communicating with each oil chamber, and a pressure applied to each oil chamber via the port. A switching valve for supplying and stopping oil is provided, and a pilot operation signal or a signal from an inclination detection sensor is used as a command signal for supplying and stopping the pressure oil.

  In that case, the first brake means can use the pilot pump pressure of the construction machine.

  Further, the second brake means can use a pressure reduced pressure oil of a main pump of a construction machine.

  In this case, the hydraulic motor can be preferably a hydraulic motor for driving a swivel of a construction machine.

  In this case, the hydraulic motor can be a hydraulic motor for traveling a construction machine.

  According to the present invention, a cylinder block is provided in a housing so as to be rotatable integrally with an output shaft, and a piston is fitted into each of a plurality of cylinder holes formed in the cylinder block to constitute a cylinder chamber. A fixed displacement piston motor that rotates the cylinder block together with the output shaft by alternately communicating the cylinder chamber with a hydraulic power source and a tank along the swash plate, on the side opposite to the output shaft One side surface is in contact with the cylinder block end surface, and a valve plate having an opening for alternately communicating the cylinder chamber with a hydraulic pressure source and a tank, and is in contact with the other side surface of the valve plate and is fixed to the housing end surface. A motor cover having a pressure oil supply / discharge port, and the valve plate is provided between the motor cover and the valve plate, and the valve plate is disposed on the end face of the cylinder block. A pressing means for pressing with a spring force, a first brake means for a parking brake provided between the outer periphery of the cylinder block and the motor cover in the housing, and pressing the other side of the valve plate with a predetermined hydraulic pressure The second brake means, the second brake means facing the other side of the valve plate, a plurality of oil chambers provided on the motor cover side and a small piston housed in each oil chamber, A port for pressurizing a small piston communicating with the oil chamber, and a switching valve for supplying and stopping the pressure oil to each oil chamber via the port, and a pilot signal as a command signal for supplying and stopping the pressure oil Slip can be suppressed by using the operation signal or the signal from the tilt detection sensor, and even when the construction machine works on a sloping ground, the construction machine swivel rotates during the stoppage. In addition, when starting from a stopped state, the slip suppression state can be instantly released by operating the switching valve, so that no excessive energy is used and smooth operation is possible. It is possible to start up, and the start-up efficiency can be improved.

  Further, in the conventional slip suppression, as shown in FIG. 4B, the reaction force F is provided by the small piston SPS on the discharge side. However, in the present invention, both grooves 50 are fed from the main pump to the slip suppression. It is possible to give the decompressed pressure oil, and it is possible to press the valve plate toward the end face of the cylinder block more reliably.

  Furthermore, in the conventional example, as shown in FIG. 4 (b), the oil chamber 30 a that houses the small piston SPS is located on the opposite side of the groove 50 in the valve plate BP that is relatively thin compared to other adjacent members. Due to the necessity of forming, there is a problem that labor, accuracy and rigidity are required for processing. However, in the present invention, since the oil chamber that houses the small piston SPS is provided on the motor cover side, such a problem with the valve plate BP is eliminated.

It is a longitudinal cross-sectional view of the front of the hydraulic motor of the Example by this invention. It is a block diagram explaining the relationship between the control signal SG to the switching valve 110 of FIG. 1A, the pressure oil supply unit to the switching valve 110, and the control signal SG generating unit. It is a longitudinal cross-sectional view of the front along the axial direction of the conventional hydraulic motor. FIG. 3 is a longitudinal sectional view in a direction perpendicular to the section of FIG. 2. It is a figure which shows the shape of a valve plate, Comprising: (a) is a front view, (b) is the zz sectional drawing of (a).

  Hereinafter, preferred embodiments of the present invention will be described in detail.

  In the following description, the reference numerals in FIG. 1A that correspond to those in FIGS. 2 to 4 are the same components and will not be described in order to avoid duplication.

  In FIG. 1A, reference numeral 100 denotes a small piston pressurizing port provided on the outer peripheral portion of the motor cover 30. The port 100 is connected to an oil chamber 100a facing the right end surface of the valve plate BP and a flow path 100b. A small piston SPS is accommodated in the oil chamber 100a.

  Reference numeral 110 is a switching valve for ON and OFF, and is supplied with pressure oil from a pilot pump such as a trochoid pump that supplies pressure oil to a remote control valve of a construction machine (not shown). The outlet side of the valve 110 is connected to the port 100. Reference symbol SG is an ON / OFF command signal, and this signal SG may be a hydraulic signal using a pilot operation pressure signal or a corresponding electrical signal. Therefore, when the hydraulic motor is stopped, the pressure oil decompressed from the main pump is applied to the small piston SPS via the flow path 100b, so that the left end surface of the piston presses the valve plate BP, resulting in the valve plate The BP presses the left end surface of the cylinder block 16 to suppress the slip. Therefore, even if there is a rotational load acting on the output shaft 18 of the hydraulic motor in a stopped state on an inclined ground or the like, the cylinder block 16 is prevented from rotating by the slip suppressing action due to static friction. Note that the pressure oil from the main pump can be used by depressurizing as the pressure oil to the switching valve 110.

  Further, the hydraulic oil sealed in the oil chamber HR in addition to the slip suppression action due to friction leaks from the gap between the cylinder block 16 and the valve plate BP as the pressure rises, and the cylinder block 16 rotates a little. In order to reduce the amount of leakage of the hydraulic oil, the valve plate BP presses the right end surface of the cylinder block 16 and is prevented from rotating.

  When the control signal SG for starting is given from the stop state of the construction machine, the switching valve 110 is cut off, so that the pressure of the pressure oil depressurized from the main pump applied to the small piston SPS disappears, and the valve plate The gap between the BP and the cylinder block 16 returns to the gap due to the predetermined pressure set by the bush 60a and the flat spring 60b. Since the static friction force does not act on the cylinder block 16, the start-up becomes smooth and the state of dynamic friction is further increased. Will be migrated.

  FIG. 1B is a block diagram illustrating the relationship between the control signal SG to the switching valve 110 of FIG. 1A, the pressure oil supply unit to the switching valve 110, and the control signal SG generation unit. In the figure, the switching valve 110 has two switching positions (a) and (b). In the state shown in the figure, the control signal SG to the pressure receiving part 110c is at a low pressure L and is in the switching position (b) by the force of the spring 110e, and the pressure oil from the pressure oil supply part 110b is supplied to the pump port 100. Has been. In this state, as described above, the cylinder block 16 and the valve plate BP are in a state in which slip is suppressed.

  On the other hand, when the control signal SG from the slip suppression release signal generation unit 110a is high pressure H, the switching valve 110 is switched to the switching position (a) by the pressure oil acting on the pressure receiving unit 110c, and the pressure oil from the pressure oil supply unit 110b. Is closed and the port 100 communicates with the tank T, so that the state in which the slip is suppressed is released. Reference numeral 110d is an electro-oil converting unit when the signal from the slip suppression cancellation signal generating unit 110a is an electric signal. In addition, when the pressure receiving part 110c is a solenoid type solenoid valve, this electro-oil conversion part is unnecessary.

In the present invention, the slip suppression release signal generation unit 110a is classified into a remote control valve operation (pressure) signal method and an inclination angle sensor method. As an inclination angle sensor system, for example, a magnet operation type float switch (manufactured by NA Corporation) can be provided in a tank of a construction machine or an oil chamber in a pump. A small wide angle tilt angle sensor (manufactured by Green Sokki Co., Ltd.) having a hybrid mechanism that uses both a weight and a float can also be used.

  As another example, a commercially available gyro sensor or gyroscope can be used. The electrical signal when the tilt detection sensor S detects the tilt state from the non-tilt state normally changes from L to H, and H and L obtained by inverting this signal correspond to the control signal SG. .

  In Table 1 below, in the state where the engine of the construction machine is not stopped, the detection signals L (non-tilt) and H (tilt) of the tilt detection sensor provided in the construction machine and the control signal SG according to the presence / absence of the start command The generation conditions of are shown. In addition, (a), (b) described in each frame of the switching valve ON / OFF column corresponds to the switching position of the valve 110.

  In the case of a swing-up operation on a sloping ground where slip is a particular concern, if the timing of the release command of the slip suppression function is almost the same as the operation of the hydraulic motor, the swinging body tends to fall in the direction of gravity, so it starts. It may be a load of time. In such a case, it is preferable to cancel the slip suppression function immediately before the hydraulic motor starts to operate. Here, in detail, the operation of the hydraulic motor means that the output shaft starts to rotate by overcoming the internal frictional resistance and the external reaction force.

  Although the preferred embodiments of the present invention have been described with reference to the drawings, those skilled in the art can naturally make various modifications based on the above drawings and descriptions.

DESCRIPTION OF SYMBOLS 10 Housing 12 Cylindrical roller bearing 14 Needle bearing 16 Cylinder block 18 Output shaft 20 Retainer 22 Swash plate 30 Motor cover 30a Oil chamber 30b Flow path 40 Brake device 40a Piston 40b Fixed side friction plate and rotation side friction plate 40c Spring 40d Cylinder 50 Groove 50a Discharge side port 50b Supply side port 60a Bushing 60b Sarah spring 100 Port for pressurizing small piston 100a Oil chamber 100b Flow path 110 Switching valve HR Oil chamber PS Piston RF Relief valve SPS Small piston SG Command signal BP Valve plate

Claims (5)

A cylinder block is provided in the housing so as to be rotatable integrally with the output shaft, and a piston is fitted into each of a plurality of cylinder holes formed in the cylinder block to form a cylinder chamber. The piston is moved along the swash plate. A fixed capacity type or variable capacity type piston motor that is slidable and rotates the cylinder block together with the output shaft by alternately communicating the cylinder chamber with a hydraulic pressure source and a tank, wherein the piston chamber is opposite to the output shaft. One side surface is in contact with the end surface of the cylinder block, a valve plate having an opening for alternately communicating the cylinder chamber with a hydraulic pressure source and a tank, and another side surface of the valve plate is in contact with and fixed to the end surface of the housing. A motor cover having an oil supply / discharge port; and the valve plate disposed between the motor cover and the valve plate on the end face of the cylinder block. A pressing means for pressing with a force, a first brake means for a parking brake provided between the outer periphery of the cylinder block and the motor cover in the housing, and pressing the other side of the valve plate with a predetermined hydraulic pressure. Second braking means
The second brake means includes a plurality of oil chambers provided on the motor cover side facing the other side surface of the valve plate, a small piston housed in each oil chamber, and a small piston addition communicating with each oil chamber. A pressure port and a switching valve for supplying and stopping the pressure oil to each oil chamber via the port, and from the pilot operation signal or the inclination detection sensor as a command signal for supplying and stopping the pressure oil A hydraulic motor having a slip suppression and start-up efficiency improving function characterized by using the above signal.   2. The hydraulic motor having a slip suppression and start efficiency improving function according to claim 1, wherein the first brake means uses a pilot pump pressure of a construction machine.   The hydraulic motor having a slip suppression and start efficiency improving function according to claim 1, wherein the second brake means uses pressure oil decompressed from a main pump of a construction machine.   4. The hydraulic motor having a slip suppression and startup efficiency improving function according to claim 1, wherein the hydraulic motor is a hydraulic motor for driving a swivel of a construction machine.   The hydraulic motor having a slip suppression and start-up efficiency improving function according to any one of claims 1 to 3, wherein the hydraulic motor is a hydraulic motor for traveling a construction machine.

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