JPS6235552B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a friction plate type speed reducer that controls a friction clutch so as to obtain a steplessly decelerated rotation output from a constant speed rotation input source.

Conventionally, as a method of engaging the friction plates of a friction plate clutch using a hydraulic friction plate, or a friction plate type reducer that transmits power by applying slip to the friction plate and decelerating the rotation from a constant rotation input shaft. Pressure is applied to the pressure plate in contact with the end friction plate that pressurizes the overlapping friction plates.As a method of applying pressure, a hydraulic cylinder is constructed in the device and the cylinder or piston member of the hydraulic cylinder is applied to the pressure plate directly, indirectly, There are two types of hydraulic cylinders, one in which the hydraulic cylinder rotates together with the friction plate when the friction plate engages the other, and one in which the hydraulic cylinder is fixed. In the former case, a hydraulic cylinder is constructed on the shaft that transmits power and the hydraulic cylinder is supported on the shaft, but the construction becomes complicated;
The moment of inertia of the rotating shaft increases, the rotating shaft becomes longer, and pressure oil must be guided to the hydraulic cylinder via a rotating joint that supplies pressure oil from some part. With a normal rotating joint, the normal pressure is 15
Since it is as low as about Kg/cm ² , the hydraulic cylinder is made large, which further increases the moment of inertia of the rotating shaft.

On the other hand, in the latter case where the pressing force of the friction plate is obtained by a hydraulic cylinder, the hydraulic cylinder is fixed, so the working pressure can be 70 kg/cm ² , which is usually determined from the rating of the hydraulic valve, or it can be changed if necessary. The above hydraulic pressure can be used. When the hydraulic cylinder is fixed and the friction plate is pressed, the friction plate engages and rotates, and also slides on some part, usually the surface of the pressing plate of the friction plate and the end of the piston of the hydraulic cylinder. Therefore, since this part slides under a large thrust, the PV value will also be large. Therefore, a rolling bearing is inserted into this part, but if a rolling bearing is used to transmit a large amount of power, it will generate a lot of noise and a large amount of heat. Also, if no measures are taken, the pressing force must be reduced and the number of friction plates must be increased. In a friction plate type reducer that performs control to reduce speed, it is difficult to control the output rotation speed, and the output rotation speed becomes unstable.

For the above, the piston of a single hydraulic cylinder, which is fixed to a housing containing the device and configured around the outer circumference of the rotating shaft, is brought into sliding contact with the sliding plate that rotates together with the pressing plate of the friction plate, and the hydraulic cylinder is moved through the inside of the piston. When pressure oil is supplied from the chamber to the sliding portion through an orifice, the pressure between the sliding plate and the piston is increased to increase the pressing force against the friction plate, and a high-output, compact power transmission device can be obtained. However, such a hydraulic cylinder has a large device, and as the piston diameter increases, it is difficult to accurately control the concentricity and cylindricity of the stepped part, and the sliding resistance of the O-ring of the piston seal is large. As a result, the piston becomes unable to move smoothly.

The present invention is a friction plate type speed reducer that engages friction plates to create a slip between the friction plates and provides an output shaft with a steplessly reduced rotation speed, in which a hydraulic cylinder is fixed and a large-capacity, small-sized device is obtained. The object of the present invention is to provide a friction plate pressing section that can be used as a friction plate.

The present invention connects an input shaft and an output shaft with a friction plate, and fixes a fixed hydraulic cylinder that presses the friction plate fixed to the input shaft and the output shaft in the axial direction to a housing that houses the device on the outer periphery of the output shaft. In a device that changes the rotational speed of an output shaft by adjusting the hydraulic pressure applied to the hydraulic cylinder and applying a slide to the friction plate, the piston of the hydraulic cylinder is configured to press a pressing plate that presses the friction plate. A plurality of hydraulic cylinders are fixedly arranged on the circumference, each of which has a piston in contact with the end surface of the main piston, which is guided by a fixed guide and moves toward a pressing plate that presses the main piston. A small hole is provided that passes through the piston via an orifice and is closely sealed to the main piston surface, and an oil hole is provided in the main piston to guide pressure oil to the lubricating groove between the main piston and the pressing plate. This increases the load capacity between the pressing plate and the piston.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of a friction plate type speed reducer of the present invention, and FIG. 2 is a partially enlarged view of FIG. 1.

The input shaft 1 is supported by two rolling bearings 2 on a bearing flange 3.
is attached to the housing 4. A seal cover 5 is attached to the bearing flange 3 and includes a shaft seal portion for preventing oil from leaking from the input shaft 1. An oil stop plate 6 is fixed to the lower part of the bearing flange 3 so that its upper end reaches the middle of the rolling elements at the bottom of the rolling bearing 2, and the space between it and the outer ring of the rolling bearing 2 serves as an oil stop when the bearing 2 is stopped. ing. An internal gear 7 is attached to the input shaft 1 by bolts 8 so as to transmit rotation of the input shaft 1.

The output shaft 9 is supported by being fitted into inner rings of a rolling bearing 10 housed in a bearing flange 11 fixed to the housing 4 and a rolling bearing 12 fitted into the input shaft 1. A seal cover 13 for sealing the output shaft 9 is attached to the bearing flange 11. A disc 14 is fitted into the bearing flange 11 in contact with the rolling bearing 10 so as to fix the rolling bearing 10 in the axial direction and to retain oil when stopped.
It is locked by a retaining ring 15 for the hole. Similarly, in the rolling bearing 12, the disc 16 is fixed by a hole stopper shaft 17, and an oil sump is also formed.

A gear 18 is fixed to the right side of the output shaft 9 by a set screw 19, and an electromagnetic rotation detector 20 whose sensing piece is the outer periphery of the gear 18 is mounted on the seal cover 13.
is screwed in and detects the rotation speed using an electrical signal. Further, the cover 21 is fixed to the seal cover 13 to prevent foreign matter from entering the rotation detection chamber 22 from the outside.

The outer ring of the rolling bearing 23 is fitted into the end of the bearing flange 11, and the inner ring thereof is fitted into the end of the internal gear 7.
An input shaft 1 is supported via an internal gear 7. An oil sump plate 24 is attached to the bearing flange 11 so that its upper end reaches the lower ball of the rolling bearing 23.

In FIG. 2, a cylinder 25 is press-fitted into the bearing flange 11, and this cylinder 25
A piston 26 is slid into. piston 26
There are a plurality of orifices 28 on the circumference of the cylinder 25, and orifices 28 are bored in two of the pistons 27 at symmetrical positions to allow pressure oil to flow from the right side of the piston 27 to the left side. It opens into hole 27'. A main piston 29 is slid into the bearing flange 11, and its left end surface is in sliding contact with a sliding plate 41 that rotates and pushes the friction plate. The pin 30 is driven into the bearing flange 11 to prevent the main piston 29 from rotating, and a bushing 31 is press-fitted into the main piston 29 so that the pin 3
0 moves smoothly in the axial direction.

A plurality of coil springs 32 are built into the outer periphery of the main piston 29. One end of the spring 32 is fitted into the bearing flange 11 and abuts against a disc 34 fixed by a retaining ring 33 for the hole, and the other end is The main piston 29 is in contact with the main piston 29, and the main piston 29 is pressed against the bearing flange 11 when there is no pressure oil in the cylinder chamber 35 or when the pressure is low.

Pressure oil that controls the pressing force of the friction plate passes through the oil passage 47 of the bearing flange 11 and enters the groove 36 on the circumference of the side surface of the cylinder 25, and then passes through the oil hole 40 and is distributed to each cylinder chamber 35. oil and acts on the pistons 27, 26. Two of the pistons 27 are provided with orifices 28 as described above, and the pressure oil escapes to the left, passes through the oil hole 57 of the main piston 29, and is led to the oil groove 58 on the left side circumference.

A plurality of friction plates 37 having a powder alloy sintered on both sides and having a large number of oil grooves are engaged with the internal gear 7 by the gears on the outer periphery. A mating plate 38, which is a steel plate, is inserted. A gear is cut on the inner periphery of the mating plate 38, and meshes with an external gear cut on the output shaft 9. At the right end of the friction plate portion, which is a combination of the plurality of friction plates 37 and the mating plate 38, a pressing plate 39 formed by cutting an external gear is engaged with the internal gear 7. Furthermore, the sliding plate 41 is attached to the bolt 4 on the pressing plate 39.
It is installed with 2. A piano wire snap ring 43 is fitted into the internal gear 7 to prevent the friction plate from falling off during assembly and disassembly.

Joint flanges 44 and 45 are attached to the housing 4 and serve as an oil connection port with the outside.The joint flange 44 is attached to the upper part and is connected to a hydraulic pipe for controlling the pressing force of the friction plate. That is, the pressure oil passes through the short pipe 46, the oil passage 47 of the bearing flange 11, and the oil hole 40 of the cylinder 25, and communicates with the cylinder chamber 35. The joint flange 45 has the same shape as the joint flange 44 but has a different size, and is attached to the side of the housing 4 at right angles to the plane of the paper.A hydraulic pipe for cooling the friction plate is connected here, and the pressure oil is connected to a short pipe (not shown). , through the bearing flange, cylinder 2
It communicates with a cooling oil passage 50 around the output shaft 9 through a port 49 that penetrates inside and outside in the radial direction of the output shaft 9 .

The outer side of the output shaft 9 of the cooling oil passage 50 is the output shaft 9
It is sealed by a rotary seal 51 provided for this purpose.

The external gear into which the mating plate 38 at the end of the output shaft 9 is fitted has partially missing teeth and an oil groove 52 in the axial direction.
An oil passage 53 is provided from the end of the input shaft 1 to communicate between the rolling bearings 2, and an orifice 54 is provided in the oil passage 53.
is screwed in. An oil passage 55 passing through the bearing flange 3 from the space between the seal cover 5 and the rolling bearing 2 is provided.

The pressure oil flowing into the oil groove 52 passes through a number of grooves provided on the surface of the friction plate 37 and returns to the bottom of the housing 4 through the radial hole 56 of the internal gear 7. Rolling bearing 1 from cooling oil passage 50
An oil passage 70 for supplying oil to the bearing flange 11 is provided in the bearing flange 11.

Place orifices 2 evenly on the circumference that has already been laid out.
8 is provided on the piston 27, and the orifice 28
A small hole 57 extending in the axial direction following the hole of the piston 27 is connected to an annular oil groove 58 . The oil groove 58 may be provided in the sliding plate 41.

An air breather 59 is installed at the top of the housing 4.
is installed to allow ventilation between the inside and outside, preventing internal pressure from increasing due to thermal expansion.

The circuit diagram on the right side of FIG. 1 shows the hydraulic equipment and electrical equipment attached to this machine. Hydraulic pump 60, 61
is driven by an electric motor 62, and oil sucked in from a flange connection port 63 of the housing 4 passes through a filter 64 and is discharged from the hydraulic pumps 60, 61. Pressure oil discharged from the hydraulic pump 60 passes through the oil cooler 65 and flows into the aforementioned cooling oil passage 50 as cooling oil. Valve 66 is a safety valve.
The oil discharged from the hydraulic pump 61 flows through the flow control valve 6.
After passing through 7, it flows into the cylinder chamber 35. Valve 6
Reference numeral 8 maintains the pump discharge pressure constant, and valve 69 is an electromagnetic proportional pressure control valve that controls the pressure in proportion to an electric signal. The amplifier 71 sends an electric signal to the valve 69, and in order to maintain the target output side rotation speed, it compares and determines an externally set electric signal 72 and an electric signal 73 from the electromagnetic rotation detector 20, and then controls the valve 69. It is an operational amplifier that outputs an electrical signal 74.

When the input shaft 1 is driven and rotated by the prime mover, the friction plate 37 coupled to the internal gear 7 rotates at the same speed. The pressure oil led to the cylinder chamber 35 is transferred to the valve 6
9 is controlled and raised, the pistons 26 and 27 push the main piston 29, the main piston 29 pushes the sliding plate 41 which rotates at the same time, and the friction plate 37 clamps the mating plate 38 via the pressing plate 39. , rotational force due to frictional force is transmitted to the mating plate 38. The mating plate 38 is connected to the output shaft 9, so that rotational force is transmitted to the output shaft 9 and drives the rotary machine connected to the output shaft 9.

The transmission torque T of the friction plate part is the effective radius of the friction surface R, the number of friction surfaces n, the pressing force W, the effective efficiency of the friction surface η, and the friction coefficient μ, then T=μ×R×w×n×η ……( 1). When the driven machine is a fluid machine, the driving torque T is the rotation speed N and the dimensionless coefficient C. Therefore, if the friction plate pressing force W is controlled, the friction plate 37 and the mating plate 38 will slip, making it possible to control the rotational speed of the driven machine. That is, by controlling the hydraulic pressure that presses the pistons 26 and 27, an arbitrary deceleration can be obtained. When the hydraulic pressure of the hydraulic pump 61 is reduced to below a certain value by controlling the valve 69, the pistons 26 and 27 move to the right in FIGS. 1 and 2 through the main piston 29 due to the force of the coil spring 32, and the sliding plate Since the pressing force of 41 is removed, the friction plate 3
7 and the mating plate 38 almost completely slide, and the rotation of the output shaft 9 becomes the minimum.

The hydraulic pressure that presses the main piston 29 against the sliding plate 41 passes through the orifice 28 and enters the oil groove 58 from the oil hole 57, and from the oil groove 58, the piston 29 and the sliding plate 4
The pressure oil flows in the radial direction through the sliding surface of No. 1, and the pressure drops. Pressure oil is discharged against the pressure force between the sliding plate 41 and the end surface of the main piston 29, and fluid lubrication can be achieved between them. Since the amount of lubricating oil required may be extremely small, it is desirable that the piston 26 and the sliding plate 41 be in mirror surface contact so that the amount of oil passing through them is small.

As shown in FIG. 2, the outer diameter of the main piston 29 in contact with the sliding plate 41 is R ₁ , the inner diameter of the main piston 29 is R ₄ , the outer diameter of the oil groove 58 is R ₂ , the oil groove 5
8 is selected so that the total reaction force due to the _pressure distribution of the supplied pressure oil between the main piston 29 and the sliding plate 41 is approximately equal to the thrust force of the cylinder chamber 35.

Now, assuming that the supply oil pressure to the cylinder chamber 35 is P, the cross-sectional area of one cylinder chamber 35 is a, the number of cylinder chambers 35 is n, the thrust force W ₁ of the main piston 29 is W ₁ =P×a×n, and the sliding Reaction force between plate 41 and main piston 29
W ₂ is However, since W ₁ is slightly larger than W _{2 and} W 1 ≈W ₂ , the surface pressure on the sliding surface can be extremely low, and the life of the sliding bearing is long.

These pressure oils are selected to be about 70 kg/cm ² as an example.

The pressure oil discharged from the hydraulic pump 60 has a set pressure of 1 to 2 kg/cm ² for lubrication and cooling.
The oil passes through the oil cooler 65, is cooled, reaches the joint flange 45, passes through a short pipe, passes through the port 49 of the piston 25, and reaches the cooling oil passage 50 on the outer periphery of the output shaft 9. This pressure oil flows to the left in FIG. 1, passes through the oil groove 52, lubricates the rolling bearing 12, and has its flow rate adjusted by the orifice 54.
The oil passes through the oil passage 53, lubricates the two rolling bearings 2 by crossfeed, and flows down the housing 4 through the oil passage 55, while overflowing from the oil stop plate 6 and flowing down.

The cooling hydraulic oil that has reached the oil groove 52 flows through the orifice 54.
The pressure drop caused by the orifice 54 is small, and the fluid passes between the friction plate 37 and the mating plate 38 and is discharged through the hole 56 of the internal gear 7. At that time, the oil that has lost some pressure is the internal gear 7.
The oil flows to the right in FIG. 1 through the tooth grooves, lubricates the rolling bearing 23 from the space in front of the disc 34, and flows down through the oil hole 75 of the oil receiver flange 11. On the other hand, the cooling oil that passes through the oil passage 70 from the cooling oil passage 50 and lubricates the rolling bearing 10 flows down through the oil escape hole 76 of the bearing flange 11.

When the friction plate 37 and the mating plate 38 are in a sliding state and the output shaft 9 is rotating at a reduced speed, the friction plate 3 generates heat.
7. It is designed to be taken away by pressure oil passing through the mating plate 38.

As described above, in the friction plate type reducer of the present invention, an oil groove is provided between the main piston and the sliding plate that applies a pressing force to the friction plate and the mating plate, and the pressure oil of the piston that presses the sliding plate is inserted into this oil groove. As a result, it is possible to provide a sliding bearing with a large load capacity and a long life between the main piston and the sliding plate while reducing the surface pressure on the sliding surface. An orifice is provided in the oil passage between the piston and the sliding plate, and the sliding surface is precisely finished to reduce leakage, and because it receives the thrust of the piston, the piston thrust and the reaction force of the sliding part are almost equal, so the pressure is reduced. This state is maintained even if the friction plate and the mating plate are changed, and the supplied hydraulic pressure can be varied over a wide range in the pressure control that causes the friction plate and the mating plate to slip.

Because the movement of the main piston relies on a plurality of circumferentially arranged small diameter pistons 26, 27, the pistons 26, 27 and cylinder 25 can be precisely finished and are suitable for applying high pressure oil. It is suitable for piston 26, since there is no need to use a sealing ring between the piston and cylinder due to the precision finish.
27 has little sliding resistance, and therefore, the main piston 29 has only sliding resistance between metals, so hydraulic pressure is effectively applied to the main piston 29, and when the main piston 29 is reciprocated, the pump pressure is increased. The difference in operating pressure when lowering and lowering is small. As for the cooling of the friction plate, since it passes through the outer periphery of the rotating shaft, it is easy to guide the oil passage for lubrication of each bearing, and there is no need for a rotating joint or a long hole oil passage passing through the shaft center.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of an embodiment of the present invention, FIG. 2 is a partially enlarged view of FIG. 1, and FIG. 3 is a cross-sectional view taken along line AA in FIG. 1...Input shaft, 4...Housing, 7...Internal gear, 9...Output shaft, 11...Bearing flange, 2
5...Cylinder, 26, 27...Piston, 28
... Orifice, 29 ... Main piston, 30 ...
Pin, 31...Button, 32...Coil spring,
33... Retaining ring for hole, 34... Disc, 35... Cylinder chamber, 36... Groove, 37... Friction plate, 38...
mating plate, 39...pressing plate, 41...sliding plate,
44, 45...Joint flange, 46...Short pipe, 5
7... Pore, 58... Oil groove.

Claims (1)

[Claims] 1. A device for decelerating and rotating an output shaft by applying sliding between friction plates, which comprises a plurality of hydraulic cylinders fixed to a housing housing the device and arranged around the outer periphery of a rotating shaft. Each piston of the hydraulic cylinder is pressed against the main piston so that the main piston, which is guided so as to be axially movable on the outer periphery, and the sliding plate that rotates together with the pressing plate of the friction plate are brought into sliding contact. An oil hole leading from the hydraulic cylinder chamber to the main piston surface via an orifice is provided in the piston of the section, and an oil hole that follows the oil hole is provided in the main piston to connect the sliding plate or the main piston or the sliding plate and the main piston. A friction plate type reducer that guides operating pressure oil through a provided oil groove. 2 Among the pistons of the plurality of hydraulic cylinders arranged around the outer periphery of the rotating shaft, two pistons arranged on the extension of the rotating shaft diameter are provided with oil holes that lead from the hydraulic cylinder chamber to the main piston surface via an orifice. A friction plate type speed reducer according to claim 1.