JPH0124941B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic continuously variable transmission consisting of a combination of a fixed displacement hydraulic pump and a variable displacement hydraulic motor, and more specifically, to a hydraulic continuously variable transmission device that has its center of rotation at a pump cylinder connected to an input shaft. A hydraulic pump formed by sliding together a large number of pump plungers arranged in an annular arrangement surrounding the motor cylinder, connected to an output shaft and disposed so as to concentrically surround the pump cylinder, and a large number of motor plungers arranged in an annular arrangement surrounding the rotation center of the motor cylinder. A hydraulic closed circuit is formed between the motor cylinder and the hydraulic motor, and a pump swash plate is fixed to the motor cylinder to give reciprocating motion to each pump plunger as the motor cylinder and the pump cylinder rotate relative to each other. The present invention relates to a transmission case in which a motor swash plate is tiltably supported, which gives reciprocating motion to each motor plunger as the motor cylinder rotates, and can arbitrarily adjust the reciprocating stroke.

In such a transmission, a motor shoe that is in sliding contact with a motor swash plate is swingably connected to the outer end of each motor plunger, a common seat plate is stacked on the back of these shoes, and a motor shoe is slidably connected to the back of the seat plate. There is a known device in which a presser plate that comes into contact is fixed to a swash plate holder that supports the motor swash plate to prevent the motor shoe from floating even if the thrust of the motor plunger suddenly decreases due to pressure fluctuations within the motor cylinder. However, it is extremely difficult to maintain the motor shoe, the seat plate, and the presser plate in contact with each other at all times in terms of processing accuracy, so it is not easy in practice to obtain a satisfactory effect of preventing the motor shoe from lifting.

The present invention has been proposed in view of the above, and is capable of effectively suppressing the lifting and vibration of the motor shoe and preventing unnecessary side pressure from being applied to each of the motor plungers. The purpose of the present invention is to provide a step-change transmission.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Reference numeral 1 denotes a transmission case formed by combining two case halves 1a and 1b divided in the longitudinal direction, and a transmission device equipped thereon is a hydraulic pump P and It is composed of a hydraulic motor M.

The hydraulic pump P includes a pump cylinder 4 whose center portion is connected to an input shaft 2 by a spline joint 3, and a large number of cylinder holes 5, 5... provided in an annular arrangement surrounding the rotation center of the pump cylinder 4. It has a large number of pump plungers 6, 6, . On the other hand, the hydraulic motor M includes a motor cylinder 8 arranged to concentrically surround the pump cylinder 4 and rotate relative to it, and a motor cylinder 8 provided so as to surround the center of rotation of the motor cylinder 8. A large number of cylinder holes 9, 9 arranged in an annular manner have a large number of motor plungers 10, 10, which are slidably engaged with each other.

A pair of support shafts 11 and 11' are protruded from both axial end surfaces of the motor cylinder 8, and one support shaft 1
1 is supported by the end wall of the right case half 1b via a ball bearing 12, and the other support shaft 11' is supported by the end wall of the left case half 1a via a needle bearing 13. A retaining ring 14 that clamps the inner race 12a of the ball bearing 12 together with the motor cylinder 8 is attached to the outer end of one of the support shafts 11.
is locked, and another stop ring 15 that is locked to the outer edge of the outer race 12b is attached to the right case half 1.
a presser plate 17 that is engaged with the annular recess 16 on the outer surface of the end wall of b and further abuts the outer end of the outer race 12b;
is removably fixed to the right case half 1b by bolts 18, thus preventing the ball bearing 12 and the support shaft 11 from moving in the axial direction with respect to the right case half 1b.

The other support shaft 11' is integrally formed with a gear 19 to serve as an output shaft, and the output of the hydraulic motor M is taken out from the gear 19 and transmitted to the differential gear device 21 via the intermediate gear 20. It's getting old.

A pump swash plate 22 that is inclined at a certain angle with respect to each pump plunger 6 is fixed inside the motor cylinder 8, and a pump shoe 6a that is in sliding contact with the slope of the pump swash plate 22 is attached to the outer end of each pump plunger 6. It is attached so that it can be swung freely. Thus, the pump swash plate 22 can cause each pump plunger 6 to reciprocate as the pump cylinder 4 rotates, thereby repeating the suction and discharge strokes.

In the transmission case 1, a swash plate holder 24 surrounding the vicinity of the output shaft 11' of the motor cylinder 8 has a pair of trunnion shafts 24a protruding from both outer surfaces thereof.
A motor swash plate 23, which is tiltably supported via the swash plate holder 24 and faces the outer end of each motor plunger 10, is fitted into the swash plate holder 24. Therefore,
The motor swash plate 23 tilts together with the swash plate holder 24 around the trunnion shaft 24a, so that the angle of inclination with respect to the axis of the motor cylinder 8 can be arbitrarily changed.

Further, an integral annular motor shoe 70 is supported on the inclined surface of the motor swash plate 23. This motor shoe 70 has a radial bearing 71 on its outer peripheral surface.
The motor shoe 70 is supported by the swash plate holder 24 via a thrust bearing 74, and the outer peripheral step 70a on the rear surface of the motor shoe 70 is pressed by a presser plate 73 fixed to the swash plate holder 24 with bolts 72 via a thrust bearing 74. It can always rotate at a fixed position and slide on the motor swash plate 23.

The motor show 70 includes a motor plunger 10,
10... are all connected via a swingable connecting rod 75. That is, each motor plunger 10 has a cylindrical bottomed hole 76 that opens on its outer end surface,
The connecting rod 75 inserted into the hole 76 is swingably connected to the motor plunger 10 via a ball joint 75a at its inner end.
5 protrudes long outside the bottomed hole 76, and is swingably connected to the motor shoe 70 via a ball joint 75a at its outer end.

Further, the motor shoe 70 is connected to the motor cylinder 8 via a universal joint 77. Universal joint 77
is composed of a joint inner ring 79 spline-coupled to the outer periphery of the motor cylinder 8 at a proper location, and an annular flexible link 80 interposed between the joint inner ring 79 and the motor shoe 70. The flexible link 80 is connected to a pair of pivot shafts 81 , 81 to the joint inner ring 79, and via another pair of pivots 82, 82 to the motor shoe 70, respectively. At this time, the pivots 81, 81 and 82, 82 are respectively arranged on two mutually orthogonal diameter lines of the swivel link 80. 83 and 84 are respectively axis 8
This is a bearing for 1,82.

When the joint inner ring 79 is rotated from the motor cylinder 8, the rotational torque is transmitted to the flexible link 80 via the pivot shafts 82, 82, and
rotates while swinging according to the inclination of the motor swash plate 23 and transmits rotational torque to the motor shoe 70 via the pivot shafts 81, 81, so the motor shoe 70 rotates in synchronization with the motor cylinder 8. Thus, the motor swash plate 23 can cause each motor plunger 10 to reciprocate through the motor shoe 70 and the connecting rod 75 as the motor cylinder 8 rotates, thereby repeating the expansion and contraction strokes.

The stroke of the motor plungers 10 can then be adjusted steplessly from zero to the maximum by tilting the motor swash plate 23 from an upright position perpendicular to each motor plunger 10 to the maximum tilted position shown.

A hydraulic closed circuit is formed between the hydraulic pump P and the hydraulic motor M via a distribution panel D and a distribution ring 25, which will be described later. When the pump cylinder 4 is rotated by the input shaft 2, high-pressure hydraulic oil discharged from the cylinder hole 5 that accommodates the pump plunger 6 on the discharge stroke flows into the cylinder hole 9 that accommodates the motor plunger 10 on the expansion stroke. On the other hand, the hydraulic oil discharged from the cylinder hole 9 that accommodates the motor plunger 10 in the contraction stroke returns to the cylinder hole 5 that accommodates the pump plunger 6 in the suction stroke.
The pump plunger 6 in the discharge stroke is connected to the pump swash plate 22
The motor cylinder 8 is rotated by the sum of the reaction torque applied to the motor cylinder 8 via the motor cylinder 8 and the reaction torque that the motor plunger 10 receives from the motor swash plate 23 during the expansion stroke.

During operation of the motor cylinder 8, due to the inclination of the motor swash plate 23, the rotational loci of the centers of the ball joints 75a, 75b at both ends of the connecting rod 75 do not fit on the same cylindrical surface, so that the two rotational loci are misaligned. Accordingly, the connecting rod 75 swings about the ball joint 75a as a fulcrum within the bottomed hole 76 of the motor plunger 10, and its swing is not restrained by the motor plunger 10 in any way. Approximately half of the 10 groups of motor plungers are always in the expansion stroke, and the high oil pressure in the motor oil chambers on the rear side connects the half circumference of the annular motor shoe 70 to the motor swash plate 2 via the connecting rod 75.
3, the pressing force also extends to the other half of the motor shoe 70. Therefore, the entire sliding surface of the motor shoe 70 is covered with the motor swash plate 2.
As a result of being constantly pressed against the motor swash plate 3, even if a sudden pressure drop occurs for some reason in the motor oil chamber on the contraction stroke side, a part of the motor swash plate 70 will not touch the motor swash plate 2.
It never rises above 3.

In this case, the gear ratio of the motor cylinder 8 to the pump cylinder 4 is given by the following equation.

Speed ratio = rotation speed of pump cylinder 4 / rotation speed of motor cylinder 8 = 1 + capacity of hydraulic motor M / capacity of hydraulic pump P As is clear from the above equation, change the capacity of hydraulic motor M from zero to a certain value. For example, the gear ratio can be changed from 1 to a certain required value. Incidentally, since the capacity of the hydraulic motor M is determined by the stroke of the motor plunger 10, the gear ratio can be changed from 1 to a certain value by tilting the motor swash plate 23 from the upright position to a certain inclination angle as described above. Can be adjusted in stages. A hydraulic servo motor S ₁ is provided in the mission case 1 for tilting the motor swash plate 23 .

The motor show 70 has a motor plunger 1 on the front.
It has the same number of hydraulic pockets 85 as 0, 10, .
6, 87, and 88 are drilled. Therefore, during operation of the motor cylinder 8, the pressure oil inside the motor cylinder 8 is supplied to the hydraulic pocket 85, and the pressure oil is
Since pressure is exerted on the motor shoe 70 to support the thrust applied to the motor shoe 70 from the motor plunger 10, the contact pressure between the motor shoe 70 and the motor swash plate 23 is reduced, and at the same time, the sliding surface between the motor shoe 70 and the motor swash plate 23 is reduced. can be lubricated.

The motor cylinder 8 is composed of first to fourth parts 8a to 8d divided in the axial direction. A bearing hole 9a for guiding the sliding movement of the motor plunger 10 is provided in the cylinder hole 9, and a bearing hole 9a in the cylinder hole 9 is provided in the third and fourth portions 8c and 8d.
A series of oil chamber holes 9b having a slightly larger diameter than a are provided,
The third portion 8c constitutes a distribution board D.

The first portion 8a integrally has a connecting flange 26 at the end opposite to the second portion 8b, and the flange 26
is tightly fitted into the positioning hole 27 in the end face of the second portion 8b opposite thereto, and is fixed to the second portion 8b by a plurality of bolts 28. Also the second and third
The fourth portions 8b, 8c, and 8d are positioned relative to each other by inserting dowel pins 29 and 30 into their joint portions, and are integrally connected by a plurality of bolts 31.

The input shaft 2 is supported at its outer end at the center of the support shaft 11' via a needle bearing 32, and at its inner end at the center of the distribution board D via a needle bearing 33. .

An annular spring chamber 56 is formed between the opposing peripheral surfaces of the input shaft 2 and the pump cylinder 4 adjacent to the spline joint 3 thereof, and a compression spring 57 is accommodated in the chamber 56. , its right end is elastically brought into contact with a seat plate 58 that is latched to the pump cylinder 4, and its left end is elastically abutted against a seat plate 59 that is latched to the input shaft 2. On the other hand, a stopper plate 60 facing the inner end surface of the motor cylinder 8 is engaged with a portion of the input shaft 2 that protrudes from the left end surface of the pump cylinder 4, and a needle thrust bearing 61 is interposed between these opposing surfaces. Ru. Therefore, the elastic force of the spring 57 presses the pump cylinder 4 against the distribution board D via the seat plate 58 to prevent oil leakage from their rotating and sliding parts, and the reaction force of the elastic force is seat plate 5
9, motor cylinder 8 via input shaft 2, stopper plate 60 and needle thrust bearing 61
be transmitted and supported.

The support plate 17 has a support shaft 1 of the motor cylinder 8.
A fixed shaft 35 passing through D 1 is connected via a pin 36 , and a distribution board D is connected to the inner end of this fixed shaft 35 .
A distribution ring 25 in contact with the motor cylinder 8 is eccentrically supported by the distribution ring 25.
The hollow portion 37 of d is divided into an inner chamber 37a and an outer chamber 37b. On the other hand, the distribution board D is provided with discharge and suction ports 38 and 39, and the discharge port 38 communicates between the cylinder hole 5 of the pump plunger 6 in the discharge stroke and the inner chamber 37a, and the suction port 39 between the cylinder hole 5 of the pump plunger 6 in the suction stroke and the outer chamber 3
7b are communicated with each other. Further, the distribution board D is provided with a large number of communication ports 40, 40..., which are connected to the cylinder holes 9, 9... of the motor cylinder 8.
is communicated with the inner chamber 37a or the outer chamber 37b.

Therefore, when the pump cylinder 4 rotates, the high-pressure hydraulic oil generated by the discharge stroke of the pump plunger 6 is transferred from the discharge port 38 to the inner chamber 37a, and then via the communication port 40 in communication with the inner chamber 37a to the motor plunger in the expansion stroke. 10 cylinder holes 9
On the other hand, the hydraulic oil discharged by the motor plunger 10 on the contraction stroke flows into the pump plunger 6 on the suction stroke through the communication port 40 and suction port 39 communicating with the outer chamber 37b. The hydraulic oil is returned to the cylinder hole 5, and the above-mentioned transmission from the hydraulic pump P to the hydraulic motor M is performed by such circulation of the hydraulic oil.

The fixed shaft 35 has a center hole 41 and a plurality of (two in the figure) short-circuit ports 42 passing through the side wall thereof.
43, the inner ends of these shorting ports 42 and 43 are connected to the inner chamber 37a through the center hole 41, and the outer ends thereof are connected to the outer circumferential groove 4 of the fixed shaft 35.
4 and 45, and these short-circuit ports 42 and 43 are opened and closed by rightward and leftward movement of a clutch valve 48 that slides into the center hole 41. That is, when the clutch valve 48 is in the rightward movement position, the short-circuit ports 42 and 43 are opened to communicate between the inner and outer chambers 37a and 37b, and the hydraulic oil discharged from the discharge port 38 of the distribution panel D immediately flows to the suction port. 39 and hydraulic oil is not supplied to the hydraulic motor M, the hydraulic motor M becomes inactive, a so-called clutch-off state, and then the clutch valve 48 is moved to the left to close the short-circuit port 42. , 43 are both closed, the hydraulic fluid is circulated from the hydraulic pump P to the motor M, resulting in a clutch-on state. In the intermediate position of the clutch valve 48 between them, the short circuit ports 42, 4
Circulation of hydraulic oil occurs depending on the opening degree of No. 3, resulting in a half-clutch state.

A valve rod 50 is screwed onto the tip of the clutch valve 48, and an umbrella-shaped valve body 51 is swingably connected to its spherical end 50a.
8 can be brought into close contact with the distribution board D so as to close the discharge port 38 when it moves to the left beyond the clutch-on position. The discharge port 38 is closed by the valve body 51 when the motor swash plate 23 is placed in an upright position and the gear ratio is set to 1:1. The motor cylinder 8 can be mechanically driven via the pump plunger 6 group and the pump swash plate 22, so the thrust applied to the motor swash plate 23 of the motor plunger 10 disappears, reducing the burden on each part due to the thrust. It can be reduced.

For sliding operation of the clutch valve 48, a hydraulic servo motor _S2 is provided on the fixed shaft 35.

A replenishment pump F is installed on the outside of the left case half 1a, and the pump is driven by an input shaft 2 to suck oil from an oil reservoir (not shown) to generate hydraulic oil at a constant pressure. The discharge port 52 of this pump F is connected to the distribution board D via an oil passage 53 in the input shaft 2 and further via check valves 54 and 55.
and the outer chamber 37b, respectively. Therefore, when hydraulic oil leaks from the hydraulic closed circuit of the hydraulic pump P and the hydraulic motor M, the leaked amount can be automatically replenished from the replenishment pump F.

As described above, according to the present invention, the motor swash plate 23
An integral annular motor shoe 70 is slidably supported on the inclined surface of the motor shoe 70, and a plurality of motor plungers 10, 10, . Since the motor cylinder 8 is connected to the cylinder 8 via a universal joint 77 and the motor cylinder 8 rotates the motor cylinder 70 synchronously, the high hydraulic pressure applied to some motor plungers 10 causes the motor cylinder 8 to rotate.
0 can be pressed entirely against the inclined surface of the motor swash plate 23, thereby suppressing lifting and vibration of the motor shoe 70.
Furthermore, wear and damage to the motor swash plate 23 are extremely small, and there is no generation of noise due to vibration of the motor shoe 70 and no reduction in operating efficiency due to lifting.

In addition, the articulated rod 75, which is always swingable, can efficiently transmit and receive thrust between the motor swash plate 23 and the motor plunger 10 without applying much side pressure to the motor plunger 10. It always slides smoothly without causing any twisting phenomenon, resulting in less wear and tear, and can significantly reduce frictional loss of power.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional side view showing an embodiment of the apparatus of the present invention, and FIG. 2 is a sectional view thereof taken along the line --. M... Hydraulic motor, P... Hydraulic pump, 1... Mission case, 2... Input shaft, 4... Pump cylinder,
6...Pump plunger, 8...Motor cylinder, 1
0...Motor plunger, 11'...Output shaft, 22...
Pump swash plate, 23...Motor swash plate, 70...Motor shoe, 75...Connecting rod, 77...Universal joint.

Claims (1)

[Claims] 1 A hydraulic pump P formed by sliding a plurality of pump plungers 6, 6... in an annular arrangement surrounding the rotation center of the pump cylinder 4 connected to the input shaft 2, and a hydraulic pump P connected to the output shaft 11' with the pump cylinder 4 concentrically A hydraulic motor M is formed by sliding together a large number of motor plungers 10, 10, .
A hydraulic closed circuit is formed between the motor cylinder 8 and the pump cylinder 4, and a pump swash plate 22 is fixedly installed on the motor cylinder 8 to give reciprocating motion to each pump plunger 6 as the motor cylinder 8 and the pump cylinder 4 rotate relative to each other. A motor swash plate 2 is provided in the case 1, which gives reciprocating motion to each motor plunger 10 as the motor cylinder 8 rotates, and can arbitrarily adjust the reciprocating stroke.
3, an integral annular motor shoe 70 is slidably supported on the inclined surface of the motor swash plate 23, and the plurality of motor plungers 10, 10, . . .
are connected to each other via a swingable connecting rod 75, and the motor shoe 70 and the motor cylinder 8 are connected via a universal joint 77 so that they can rotate synchronously. Continuously variable transmission.