JPH0814306B2 - Hydrostatic continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention (1) Field of Industrial Application The present invention relates to a swash plate type hydraulic pump driven by an input shaft arranged in the center of a transmission, and concentric with the input shaft. And a swash plate type hydraulic motor having the output gear of FIG. 1 are connected to each other via a hydraulic closed circuit.

(2) Conventional technology A hydrostatic continuously variable transmission of this type is disclosed in, for example, Jikho Sho 61-28.
It is already known as disclosed in Japanese Patent No. 902.

(3) Problems to be Solved by the Invention In the conventional hydrostatic continuously variable transmission of this type, since the hydraulic motor is concentrically arranged around the outer circumference of the hydraulic pump, the motor cylinder of the hydraulic motor has a large diameter. Inevitably, therefore, a relatively small-diameter output gear suitable for decelerating the load cannot be formed on the outer circumference of the motor cylinder and extends from the motor cylinder to one side in the axial direction of the hydraulic pump. It is connected to the output shaft, and its structure is complicated.

The present invention has been made in view of the above circumstances, and enables the formation of an output gear having a relatively small diameter on the outer periphery of the motor cylinder, and further contributes to reducing the load on the bearing. The purpose is to provide.

B. Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention arranges a pump cylinder of a hydraulic pump and a motor cylinder of a hydraulic motor coaxially and integrally with each other. Combined to form a cylinder block, a pump swash plate at the outer end of the pump cylinder,
In addition, the motor swash plate is placed opposite to the outer end of the motor cylinder, and the pump that supports the pump swash plate is attached to the input shaft that has the end on the motor cylinder side as the input end by penetrating the center of the cylinder block in a relatively rotatable manner. A swash plate holder is connected, and an output gear is formed on the outer periphery of the end portion of the motor cylinder on the input shaft input end side.

(2) Operation According to the above configuration, the motor cylinder can be formed to have a small diameter similarly to the pump cylinder by the coaxial arrangement of the pump cylinder and the motor cylinder, so that the output gear having a relatively small diameter is formed on the outer periphery of the motor cylinder. It becomes possible.

Further, in the above coaxial arrangement, the motor cylinder is located closer to the input shaft input end than the pump cylinder, and an output gear is formed on the outer periphery of the motor cylinder on the input shaft input end side. Since the axial distance between the input end of the input gear and the output gear of the transmission can be minimized, there is no radial load applied to the output gear from the load side. The swinging moment or bending moment acting on the continuously variable transmission is reduced, and the load on the bearing supporting the continuously variable transmission is reduced accordingly.

(3) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, in FIG. 17, U is a power unit for an automobile, which is configured by accommodating and supporting an engine E, a hydrostatic continuously variable transmission T of the present invention and a differential device Df in a casing C.

The crankshaft 1 of the engine E and the input end 2a (left end) of the input shaft 2 of the continuously variable transmission T coaxially arranged on the right end side of the crankshaft 1 are connected via a torque damper D. Further, the output gear 3 of the continuously variable transmission T is arranged as close as possible to the engine E, and meshes with the ring gear of the differential device Df. Differential Df
The left and right drive shafts 4 and 4'are arranged in parallel with the crankshaft 1 and the input shaft 2 so as to drive the left and right axles (not shown).

1 and 2, the continuously variable transmission T is a constant displacement swash plate type hydraulic pump P disposed around an input shaft 2.
And a variable displacement type swash plate type hydraulic motor M disposed around the input shaft 2 on the left side thereof.

The hydraulic pump P includes an input cylinder shaft 5 connected to the input shaft 2 via a drive gear 39, and a pump cylinder which is relatively rotatably fitted to an inner peripheral wall of an intermediate portion of the input cylinder shaft 5 via a needle bearing 6. 7 and a large number of pump plungers 9, 9 ... Slidably fitted in a large number and odd numbered cylinder holes 8, 8 ... of an annular array provided in the pump cylinder 7 so as to surround the center of rotation thereof, and these pump plungers 9 The pump swash plate 10 abutting the outer ends of the pump cylinders 9, 9 ... And the pump swash plate 10 is inclined at a constant angle with respect to the axis of the pump cylinder 7 about a virtual trunnion axis O ₁ orthogonal to the axis of the pump cylinder 7. In order to maintain the state, a pump swash plate holder 12 which supports the back surface of the swash plate 10 via a thrust roller bearing 11 is constructed. The pump swash plate holder 12 is splined to the inner peripheral wall of the input cylinder shaft 5. Pump cylinder 7
Is rotatably supported by a needle bearing 13 on an input shaft 2 penetrating its central portion.

Thus, the pump swash plate 10 can reciprocate the pump plungers 9, 9 ... While the input cylinder shaft 5 is rotating to repeat the suction and discharge strokes.

The boss of the drive gear 39 is rotatably supported by the casing C via a ball bearing 41, and the input shaft 2
The split cotter 36 locked on the outer peripheral surface prevents movement outward in the axial direction.

In order to improve the followability of the pump plunger 9 with respect to the pump swash plate 10, a coil spring 15 that biases the pump plunger 9 in the extension direction is contracted in the cylinder hole 8.

On the other hand, the hydraulic motor M is arranged coaxially with the pump cylinder 7 on the left side thereof, that is, on the side closer to the input end 2a of the input shaft 2, and with the motor cylinder 17 surrounding the rotation center thereof. A large number of motor plungers 19, 19 ... which are respectively slidably fitted into a large number and odd number of cylinder holes 18, 18 ... In an annular array provided, and these motor plungers 19, 19
The motor swash plate 20 that contacts the outer end of
The trunnion shaft 22 having a half-moon-shaped cross section that supports the back surface of the trunnion through a thrust roller bearing 21 and the swash plate anchor 23 that rotatably supports the cylindrical surface of the trunnion shaft 22.
Composed of and. The swash plate anchor 23, together with a cylindrical cylinder holder 24 connected to the right end of the swash plate anchor 23, is bolted to the casing C with a bolt 26
It is fixed in.

The motor cylinder 17 is rotatably supported by the cylinder holder 24 via a ball bearing 25, and is also rotatably supported via the needle bearing 14 by the input shaft 2 passing through the center thereof.

The left end of this motor cylinder 17, that is, the input end of the input shaft
The output gear 3 is engraved on the outer peripheral surface of the end portion on the 2a side.

To prevent its axial movement while allowing rotation of the predetermined angle of the trunnion shaft 22, arc-shaped long holes 28 drilled in the swash plate anchor 23, the axis O ₂ of the trunnion shaft 22 centered
A bolt 29 is fixed to one end surface of the trunnion shaft 22 through the through hole (see FIGS. 2 and 16).

The motor swash plate 20 is adapted to be actuated by rotation of the trunnion shaft 22 between an upright position perpendicular to the axis of the motor cylinder 17 and a maximum inclined position inclining at a certain angle. In this state, the motor plungers 19, 19,... Reciprocate with the rotation of the motor cylinder 17 to repeat the expansion and contraction strokes.

In order to improve the followability of the motor plunger 19 to the motor swash plate 20, a coil spring 30 for urging the motor plunger 19 in the extension direction is contracted in the cylinder hole 18.

The pump cylinder 7 and the motor cylinder 17 are integrated with each other to form a cylinder block B, and the cylinder block B is provided with a flange 31 protruding from the outer circumference of the input shaft 2.
And the seat plate 33 that is locked to the outer peripheral surface of the input shaft 2 prevents the movement in the axial direction. These flange 31 and seat plate
The reference numeral 33 does not hinder the relative rotation of the input shaft 2 and the cylinder block B.

The left end portion of the input shaft 2 extends so as to penetrate the motor swash plate 20, the trunnion shaft 22, and the swash plate anchor 23, and is spline-connected to the outer periphery of the left end portion thereof and is fixed to the support cylinder 45 by a split cotter 44. Between the swash plate anchor 23 and
A retainer 46 and a thrust roller bearing 47 are sequentially interposed from the 23 side. The left end of the input shaft 2 is rotatably supported by the swash plate anchor 23 via the needle bearing 48 and the retainer 46.

The input shaft 2 is provided with a hemispherical aligning body 50 which is engaged with the inner peripheral surface of the pump swash plate 10 so as to be tiltable in all directions,
A hemispherical aligning body 51 is engaged with the inner peripheral surface of the pump swash plate 10 so as to be tiltable relative to all directions.
In addition, the centering action is given to the motor swash plate 20.

The centering action of each swash plate 10, 20 is strengthened, and the pump swash plate 1
0 and the pump plungers 9, 9 ... group, the motor swash plate 20 and the motor plungers 19, 19 ... group, in order to prevent slippage in the rotational direction between each group, each swash plate 10, 20 has a corresponding plunger 9, Spherical recesses 10a, 20a are formed to engage the 19 spherical ends 9a, 19a, respectively.

A hydraulic closed circuit is formed between the hydraulic pump P and the hydraulic motor M as follows.

In the cylinder block B, between the cylinder holes 8, 8 ... Group of the pump cylinder 7 and the cylinder holes 18, 18 ... Group of the motor cylinder 17, annular inner oil passages arranged concentrically around the input shaft 2 are provided. 52 and the outer oil passage 53, the annular partition between the oil passages 52, 53, and the outer peripheral wall of the outer oil passage 53 are radially penetrated. The same number of first valve holes 5 as the cylinder holes 8, 8 ... And 18, 18 ...
4, 54 ... and second valve holes 55, 55 ... and adjacent cylinder holes 8, 8 ...
And a large number of pump ports a, a ... Communicating the first valve holes 54, 54 ... With each other, adjacent cylinder holes 18, 18 ... And the second valve hole 5
Are provided with a large number of motor ports b, b,.

The inner oil passage 52 includes a cylinder block B and an input shaft 2.
The inner oil passage is formed as an annular groove
In order to prevent oil leakage from the inner oil passage 52, a pair of rotary sliding seal rings 43 are interposed between the input shaft 2 and the cylinder block B on both left and right sides of the inner oil passage 52.

As shown in FIGS. 4 and 5, the outer oil passage 53 has an annular dovetail groove 58 formed in the outer periphery of the cylinder block B and staggered arrangement on both side walls of the dovetail groove 58. It is composed of a plurality of semi-circular recessed portions 59, 59 ... Perforated, and the open surfaces of the dovetail groove 58 and the recessed portions 59, 59 ... Are closed by a sleeve 60 welded to the outer peripheral surface of the cylinder block B. The outer oil passage 52 having such a configuration is advantageous in minimizing the high pressure volume.

The first and second valve holes 54, 55 are arranged so as to pass through the bottom wall of the recesses 59, 59 in a staggered arrangement, and correspondingly, the cylinder holes 8, 8 of the hydraulic pump P are arranged. Hydraulic pump P
... are out of phase with the cylinder holes 18, 18 ... in the circumferential direction.

By doing so, while increasing the wall thickness of the cylinder block B between the first and second valve holes 54, 54, between the valve holes 54, 55,
The interval along the axial direction of the cylinder block B can be narrowed, which can contribute to downsizing of the cylinder block B.

Also, when high oil pressure is introduced to the outer oil passage 52,
Even if both side walls of 58 are expanded and deformed, rather, the deformation increases the surface pressure of the fitting portion of the cylinder block B and the sleeve 60, thereby preventing oil leakage from the fitting portion. .

The first valve holes 54, 54 ... have spool-type first distribution valves 61,
61 and the second valve holes 55 are slidably fitted with the spool type second distribution valves 62, 62, respectively. The first eccentric ring 63 surrounding the first distribution valves 61, 61 ...
However, a second eccentric ring 64 surrounding the second distribution valves 62, 62 ... Is engaged via ball bearings 65, 66, respectively. Distribution valve
The outer ends of 61, 61 ... are the first concentric relationship with the first eccentric ring 63.
The compulsory wheel 67 and the outer ends of the second distribution valves 62, 62 ... Are connected to each other by a second compulsory wheel 68 concentric with the second eccentric wheel 64. The connection structure thereof will be described later.

The first eccentric wheel 63 is fixed to the outer circumference of the input cylinder shaft 5, and
As shown in the figure, it is held at a position eccentric by a predetermined distance ε ₁ from the center of the input shaft 2 along the eccentric direction line X ₁ . The eccentric direction line X ₁ is set at a position a predetermined angle theta ₁ retard the rotational direction R of the input cylindrical shaft 5 from the virtual trunnion axis O ₁ of the pump swash plate 10.

Thus, when the relative rotation occurs between the input cylinder shaft 5 and the pump cylinder 7, each first distribution valve 61 is moved by the first eccentric ring 63 in the first valve hole 54 so as to have a distance of twice the eccentric amount ε _1. As a stroke, the pump cylinder 7 is reciprocated between a radially inner position and an outer position.

In FIG. 6, the discharge region of the hydraulic pump P is indicated by D, and the suction region is indicated by S. In the discharge region D, the first distribution valve 61 moves from the position N ₁ (hereinafter, referred to as an eccentric neutral position) perpendicular to the eccentric direction line X ₁ to the inside position side, and moves the corresponding pump port a to the outside oil position. Hydraulic oil is pumped from the cylinder hole 8 to the outer oil passage 53 by the pump plunger 9 during the discharge stroke, while being in communication with the passage 53 and not communicating with the inner oil passage 52.

In the suction region S, the first distribution valve 61 is moving from the eccentric neutral position N ₁ to the outer position side so that the corresponding pump seat a communicates with the inner oil passage 52 and does not communicate with the outer oil passage 53. , The inner oil passage 52 by the pump plunger 9 during the suction stroke
The hydraulic oil is sucked into the cylinder hole 8 from.

Further, at the eccentric neutral position N ₁ , the first distribution valve 61 makes the corresponding pump port a incommunicable with both oil passages 52 and 53. in this case,
As shown in FIG. 6A, the pump port a of the first distribution valve 61.
The land portion 61a for closing is provided with a predetermined valve closing margin l ₁ only on the outer oil passage 53 side.

In this way, the discharge area D of the hydraulic pump P is retarded by the angle θ ₁ as compared with the case where the eccentric direction line X ₁ is matched with the virtual trunnion axis O ₁ , and the suction area S is discharged.
Wider than is set.

As shown in FIGS. 1, 2 and 8, the second eccentric wheel 64 is provided between the clutch-on position n and the clutch-off position f via the pivot shaft 76 parallel to the input shaft 2 on the cylinder holder 24. Are swingably connected.

The eccentric direction line X ₂ of the second eccentric ring 64 is the trunnion axis line.
Set from the O ₂ to a position by a predetermined angle theta ₂ binary angle in the rotational direction R of the motor cylinder 17, the eccentricity is a clutch-on position n in epsilon _2, made larger than the clutch-off position f in epsilon ₂ epsilon It is ₃ .

Thus, when the motor cylinder 17 rotates when the second eccentric wheel 64 occupies the clutch-on position n, each second distribution valve 62 is rotated.
Is the eccentric amount ε in the second valve hole 55 due to the second eccentric ring 64.
_A stroke twice as long as two strokes is reciprocated between the radially inner position and the outer position of the motor cylinder 17.

In FIG. 9, the expansion region of the hydraulic motor M is indicated by Ex and the contraction region thereof is indicated by Sh. In expansion area Ex, the second distribution valve 62 from the eccentric neutral position N ₂ have moved the inner position, the corresponding motor port b to the normal to the inner oil passage 52 communicates with the outside oil passage 53, High-pressure hydraulic oil is supplied from the outer oil passage 53 to the cylinder hole 18 of the motor plunger 19 during the expansion stroke.

In shrinkage region Sh, the second distributing valves 62 is the eccentric neutral position N ₂ have shifts along the above to the corresponding motor port b in disconnected and outside oil passage 53 communicates with the inside oil passage 52, The working oil is discharged from the cylinder hole 18 of the motor plunger 19 to the inner oil passage 52 during the contraction stroke.

Further the eccentric neutral position N _2, the second distribution valve 62 is in disconnected and Ryoaburaro 52 and 53 the corresponding motor port b. in this case,
As shown in FIG. 9A, the land portion 62a that closes the motor port b of the valve 62 is provided with a predetermined valve closing margin l ₂ only on the outer oil passage 53 side.

In this way, the expansion region Ex of the hydraulic motor M is advanced by an angle θ ₂ compared with the case where the eccentric direction line X ₂ is aligned with the trunnion axis O ₂ , and the contraction region Sh is wider than the expansion region Ex. Is set to.

Further, when the motor cylinder 17 rotates when the second eccentric wheel 64 occupies the clutch-off position f, the second distribution valve 62 is eccentric in the second valve hole 55 by the second eccentric wheel 64 as shown in FIG. The stroke is set to a distance twice the amount ε _{3, and} the motor cylinder 17 is reciprocated between the radially inner position and the outer position. At the inner and outer positions, the second distribution valve 62 causes the outer oil passage 53 to move. It is designed to be opened to the outside of the cylinder block B.

A pair of the pump ports a is provided for one cylinder hole 8 and arranged in a direction perpendicular to the sliding direction of the first distribution valve 61. Also, the motor port b has one cylinder hole.
A pair of 18 is provided side by side in the direction perpendicular to the sliding direction of the second distribution valve 62. In this way, the pump port a
In addition, it is possible to open and close the corresponding ports a and b with a relatively short stroke of each of the distribution valves 61 and 62 while securing a large total passage area of the motor port b.

Referring again to FIG. 8, the second eccentric ring 64 has its pivot shaft 76
The contact plate 79 is fixed to the peripheral wall on the opposite side with screws 80, and the cam shaft 81 axially supported by the casing C is directed to the contact plate 79 and toward the clutch off position f of the second eccentric wheel 64. It is movably engaged. An operation wire 83 is connected to a clutch lever 82 fixed to the outer end of the cam shaft 81, and a return spring 84 of the lever 82 is compressed between the clutch lever 82 and the casing C. Also, the second eccentric ring 64 is a set spring 85.
Is urged toward the clutch-on position n. The set spring 85 is contracted between the retainer 87 fixed to the outer circumference of the second eccentric ring 64 with a screw 86 and the support ring 75.

Therefore, the second eccentric wheel 64 is normally held at the clutch-on position n by the force of the set spring 85, but when the cam shaft 81 is rotated as shown by the arrow by the pulling operation of the operation wire 83, the clutch-off position is set. It is swung to f.

In the above configuration, when the input cylinder shaft 5 of the hydraulic pump P is rotated from the input device 2 with the second eccentric wheel 64 held at the clutch-on position n, the pump swash plate 10 discharges and sucks the pump plungers 9, 9. The process is given alternately.

The pump plunger 9 pumps hydraulic oil from the cylinder hole 8 to the outer oil passage 53 while passing through the discharge region D, and pumps hydraulic oil from the inner oil passage 52 to the cylinder hole 8 while passing through the suction region S. Inhale.

The high-pressure hydraulic oil sent to the outer oil passage 53 is supplied to the hydraulic motor M
Cylinder hole of motor plunger 19 in the expansion region Ex
On the other hand, the hydraulic oil is discharged from the cylinder hole 18 to the inner oil passage 52 by the motor plunger 19 located in the contraction region Sh.

During this time, the reaction torque that the pump cylinder 7 receives from the pump swash plate 10 via the pump plunger 9 in the discharge stroke and the motor plunger 19 in the expansion stroke in the motor cylinder 17
, The cylinder block B is rotated by the sum of the reaction torque received from the motor swash plate 20 and the rotation torque is transmitted from the output gear 3 to the differential device Df.

In particular, the coaxial arrangement of the pump cylinder 7 and the motor cylinder 17 allows the motor cylinder 17 to be formed to have a small diameter like the pump cylinder 7.
Since there is no obstacle such as the input cylinder shaft 5 on the outer circumference of the output cylinder 3, the output gear 3 engraved on the outer peripheral surface of the motor cylinder 17 is
Has a relatively small diameter, and the differential device Df can be sufficiently decelerated.

The gear ratio of the output gear 3 to the input cylinder shaft 5 is given by the following equation.

Therefore, if the capacity of the hydraulic motor M is changed from zero to a certain value, the gear ratio can be changed from 1 to a certain required value. Moreover, since the capacity of the hydraulic motor M is determined by the stroke of the motor plunger 19, the gear ratio is continuously controlled from 1 to a certain value by tilting the motor swash plate 20 from the upright position to a certain tilt position. can do.

By the way, in the hydraulic pump P, since the suction region S is set to have a wider angle than the discharge region D, even if the back pressure of the pump plunger 9 in the suction stroke is much lower than that of the pump plunger 9 in the discharge stroke, the cylinder The suction efficiency of the holes 8 can be effectively increased. As a result, the ejection area D
However, the efficiency of the hydraulic pump P can be improved as a whole even if a certain amount is sacrificed.

In order to maximize the efficiency, it is best to set the suction area S to 180 °.

In addition, the discharge region D has an angle θ compared to the case where the eccentric direction line X ₁ of the first eccentric ring 63 is aligned with the virtual trunnion axis O _1.
Since it is retarded by ₁ , the pump plunger 9 receives a large compressive load from the pump swash plate 10 from when the pump plunger 9 contracts a certain amount past the maximum extension point. As a result, the maximum bending moment generated in the pump plunger 9 decreases,
The object of prying between the pump plunger 9 and the opening edge of the cylinder hole 8 is alleviated, and the friction loss due to the phenomenon is significantly reduced.

On the other hand, in the hydraulic motor M, since the contraction region Sh is set to have a wider angle than the expansion region Ex, the back pressure of the motor plunger 19 during the contraction stroke can be sufficiently reduced, and the expansion region Ex
, The efficiency of the hydraulic motor M can be improved as a whole.

In order to maximize the efficiency, it is best to set the shrinkage region Sh to 180 °.

Further, since the expansion region Ex is advanced by the angle θ ₂ compared to the case where the eccentric direction line X ₂ of the second eccentric ring 64 is aligned with the trunnion axis O ₂ , the motor plunger 19 in the expansion stroke has the maximum extension point. Before reaching, the thrust reaction force of the motor swash plate 20 is released early. As a result, the maximum bending moment generated in the motor plunger 19 is reduced, so that the prying phenomenon between the motor plunger 19 and the opening edge of the cylinder hole 18 is alleviated, and the friction loss due to the phenomenon is significantly reduced.

During such operation, if the second eccentric wheel 64 is swung to the clutch-off position f, the second distribution valve 62 causes the high-pressure outer oil passage.
Since 53 is opened outside the cylinder block B, high-pressure hydraulic oil is not supplied to the hydraulic motor M, and the power transmission between the hydraulic pump P and the hydraulic motor M is cut off. That is, a so-called clutch-off state is obtained.

During operation of the hydraulic pump P and the hydraulic motor M, the pump swash plate
10 is from the pump plungers 9,9 ... group and motor swash plate 20
Receives thrust loads in the opposite directions from the motor plungers 19, 19, respectively, but the thrust load received by the pump swash plate 10 is input through the thrust roller bearing 11, the pump swash plate holder 12, the drive gear 39 and the cotter 36. The thrust load received by the motor swash plate 20 is thrust roller bearing 21, trunnion shaft 22, swash plate anchor 2
3, thrust roller bearing 47, support cylinder 45 and cotter 4
It is also supported on input shaft 2 via 4. Therefore,
The thrust load only generates a tensile stress on the input shaft 2 and does not act on the casing C supporting the shaft 2 at all.

As shown in FIGS. 6 and 7, the connection structure of the first distribution valve 61 and the compulsory wheel 67 is such that a small-diameter neck portion 61b formed in the distribution valve 61 and the neck portion 61b are engaged with each other. The cylinder holder 24 is formed with a circumferentially elongated hole 89, and an enlarged diameter hole 90 is continuously provided at one end of the elongated hole 89 so that the large outer diameter portion of the distribution valve 61 can pass therethrough. Therefore, by inserting the distribution valve 61 into the enlarged diameter hole 90 and aligning the neck portion 61b with the elongated hole 89, and then rotating the compulsory wheel 67 in the circumferential direction, the neck portion 61b can be engaged with the elongated hole 89. You can In order to maintain this engaged state, the elastic plug 91 is fitted into at least one of the expanded diameter holes 90.

As shown in FIGS. 11 and 12, the connection structure between the second distribution valve 62 and the compulsory wheel 68 is the same as the above-mentioned first distribution valve 61 and the compulsory wheel.
Since it has the same structure as the connection structure with 67, the same reference numerals are given to the corresponding parts and the detailed description thereof will be omitted.

In FIGS. 1, 2, and 5, a gear change control device 93 for controlling the angle of the motor swash plate 20 is connected to the trunnion shaft 22. This shift control device 93 has a sector gear 96 fixed to the other end of the trunnion shaft 22 by a bolt 94 and a pair of knock pins 95, 95, a worm gear 97 meshing with the sector gear 96, and a drive shaft 98 for the worm gear 97. The worm gear 97 is formed of a direct-current / reverse-rotatable direct-current electric motor 99 that is coupled to the gear box 101.
It is rotatably supported via 3. Further, the stator of the electric motor 99 is fixed to a proper position of the casing C.

In the above, the sector gear 96 and the worm gear 97 are
Although the rotation of the drive shaft 98 can be decelerated and transmitted to the trunnion shaft 22, the speed reduction device 106 is configured to be in a locked state when receiving a reverse load from the trunnion shaft 22.

Thus, if the electric motor 99 is rotated forward or backward, the rotation is reduced and transmitted from the worm gear 97 to the sector gear 96, and further transmitted to the trunnion shaft 22, which transmits the rotation in the rising direction of the motor swash plate 20 or It can be rotated in the tilting direction.

When the electric motor 99 is stopped and the motor swash plate 20 is held at an arbitrary angle, the motor swash plate 20
9,19… Receive the moment in the standing or tilting direction from the group,
The moment is transmitted to the sector gear 96 via the trunnion shaft 22.
Cannot transmit the worm gear 97 from the sector gear 96, the two gears 96, 97 exhibit a locked state and do not allow the rotation of the trunnion shaft 22, and therefore, the motor swash plate 20 is in its current position. It is securely held.

In order to restrict the upright position and the tilted position of the motor swash plate 20 by the electric motor 99, the sector gear 96 is provided with an arcuate restriction groove 104 concentric therewith, and the restriction groove 104.
A stopper pin 105 slidably engaged with the gear box 101 is fixed to the gear box 101.

Referring again to FIGS. 1 and 2, a main oil passage 108 having a deep stop is bored at the center of the input shaft 2, and the main oil passage 108 extends over substantially the entire length thereof. Is installed.

The open end of the main oil passage 108 communicates with the oil sump 110 at the bottom of the casing C via the replenishment pump 38, and the replenishment pump 38 is driven by the drive gear 39. Therefore, while the input cylinder shaft 5 is rotating, the oil in the oil sump 110 is constantly supplied to the main oil passage 1 by the replenishment pump 38.
Delivered on 08.

The oil sent to the main oil passage 108 is filtered by the oil filter 109, and then the supply hole 111 in the radial direction is formed in the input shaft 2.
And is sent to the inner oil passage 52 via. In this manner, the hydraulic closed circuit between the hydraulic pump P and the hydraulic motor M is replenished with the leaked amount of hydraulic oil.

The replenishing hole 111 is provided with a first check valve 112 for blocking the reverse flow of oil from the inner oil passage 52, and the check valve 112 is closed by a leaf spring 114 surrounding the input shaft 2. It is urged in the valve direction.

Thus, during reverse load operation, that is, during engine braking, the hydraulic motor M acts as a pump and the hydraulic pump P acts as a motor, so that the outer oil passage 53 is at a low pressure and the inner oil passage 52 is at a high pressure. Change from the inner oil passage 52 to the supply hole
The hydraulic oil tries to flow back to 111, but the backflow is blocked by the first check valve 112. Thus, the hydraulic motor M
The reverse load is reliably transmitted from the hydraulic pump P to the hydraulic pump P, and a good engine braking effect is obtained.

C. Effects of the Invention As described above, according to the present invention, although the output gear of the continuously variable transmission is formed on the outer periphery of the motor cylinder, the motor cylinder is arranged coaxially with the pump cylinder. Since the output gear can be formed to have a relatively small diameter, the load can be decelerated with a simple structure.

Further, in the coaxial arrangement, the motor cylinder is located closer to the input shaft input end than the pump cylinder, and the output gear is formed on the outer periphery of the motor cylinder on the input shaft input end side. The axial distance between the input end of the input gear and the output gear that serves as the output of the transmission can be minimized as a result of the radial load applied to the output gear from the load side. Since the moment acting on the continuously variable transmission can be effectively reduced,
This can contribute to extending the life of the bearing that supports the continuously variable transmission.

[Brief description of drawings]

The drawings show one embodiment of the present invention. Fig. 1 is a vertical plan view of a hydrostatic continuously variable transmission, and Fig. 2 is a vertical rear view of Fig. 1, Fig. 3, Fig. 4, and Fig. Fig. 5 is the III-III line, IV of Fig. 2.
-IV line and VV line sectional drawing, FIG. 6 is VI-VI of FIG.
FIG. 6A is an enlarged sectional view around the first distributing valve when the eccentric neutral position is reached in FIG. 6, and FIG.
VII-VII line sectional view, FIG. 8 is a VIII-VIII line sectional view of FIG. 1, FIG. 9 is a IX-IX line sectional view of FIG. 1 (clutch ON state), and FIG. 9A is FIG. FIG. 10 is an enlarged cross-sectional view around the second distributing valve when the eccentric neutral position is reached, FIG. 10 is an operation diagram of FIG. 9 (clutch-off state), and FIG. 11 is a XI arrow view of FIG.
FIG. 12 is a front view of the second distributing valve, FIGS.
XIII-XIII line and XIV-XIV line sectional drawing of the figure, FIG.
FIG. 16 is a sectional view taken along the line XV-XV in FIG.
FIG. 7 is a vertical cross-sectional rear view of a main part of an automobile power unit including the hydrostatic continuously variable transmission. B ... Cylinder block, E ... Engine, M ... Hydraulic motor, P ... Hydraulic pump, T ... Hydrostatic type continuously variable transmission, 1 ... Crank shaft, 2 ... Input shaft, 2a ... Input Edge, 3 ...
... output gear, 5 ... input cylinder shaft, 7 ... pump cylinder,
9 ... Pump plunger, 10 ... Pump swash plate, 17 ... Motor cylinder, 19 ... Motor plunger, 20 ... Motor swash plate

Claims (1)

[Claims] 1. A swash plate hydraulic pump (P) driven by an input shaft (2) arranged at the center of a transmission (T), and an output gear (3) concentric with the input shaft (2). In a hydrostatic continuously variable transmission in which a swash plate type hydraulic motor (M) provided is mutually connected via a hydraulic closed circuit, a pump cylinder (7) of a hydraulic pump (P) and a hydraulic motor (M) are provided. The motor cylinder (17) is coaxially arranged and integrally coupled to each other to form a cylinder block (B), and the pump swash plate (10) is provided at the outer end of the pump cylinder (7).
The motor swash plate (2
0) are placed opposite each other, and the pump swash plate is attached to the input shaft (2) having the end portion on the motor cylinder (7) side as the input end (2a) penetrating the center portion of the cylinder block (B) in a relatively rotatable manner. A pump swash plate holder (12) that supports (10) is connected, and an output gear (3) is formed on the outer circumference of the end of the motor cylinder (17) on the input shaft input end (2a) side. , Hydrostatic continuously variable transmission.