JPH08326649A - Axial piston motor - Google Patents

Abstract

PURPOSE: To provide an axial piston motor by which axial force can be efficiently converted into rotational force. CONSTITUTION: A cylinder block 23 is rotatively fitted to an upper half part in a motor main body 10. Five piston insert holes 23b are axially opened on the concentric circle of the cylinder block 23, and each piston 25 is axially slidably fitted to each piston insert hole 23b. A distributing valve 31 is arranged, by which operating fluid is sequentially supplied to these pistons 25. A cam mechanism 41 by which the axial force of each piston 25 is converted into the rotational force of the cylinder block 23 is arranged to a lower half part in the motor main body 10. A cam follower 48 journalled to a cross head 47 integrated with the pistons 25 and a cam groove 42a on the outer circumferential surface of a column cam main body 42 are fitted to the cam mechanism 41. The cross head 47 applies the rotational force to a york guide 46 while being axially moved so as to rotate the cylinder block 23 and a center shaft 51.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial piston motor which can be used in both pneumatic and hydraulic fields.

[0002]

2. Description of the Related Art Various conventional fluid pressure motors are shown in FIGS.

In the vane motor shown in FIG. 6, a rotor 62 is axially supported at an eccentric position of a cam ring 61, a vane 63 is slidably fitted in a radial direction of the rotor 62, and a tip of the vane 63 is cam-ringed. The inner surface of 61 is slidably contacted. Then, the working fluid pressurized and supplied from the high pressure port Pin is caused to act on the vane 63 to rotate the rotor 62, and a rotation output is obtained from the rotor 62. The used fluid is discharged to the outside from the low pressure port Po.

The gear motor shown in FIG. 7 has a casing.
Two gears 66 and 67, which are rotatably supported inside the gear 65, are engaged with each other, and the gear 6 is driven by the working fluid supplied under pressure from the high pressure port Pin of the casing 65 and discharged from the low pressure port Po.
The rotation output is obtained by rotating 6, 67 in the direction of the arrow.

The radial piston motor shown in FIG. 8 has three to six cylinders 71 arranged radially in a star shape,
The reciprocating motion of the piston 72 in each cylinder 71 is controlled by the crank mechanism.
It is converted by the 73 into rotational movement of the output shaft 74. A rotary valve 75 provided coaxially with the output shaft 74 switches the working fluid sequentially pressurized and supplied into each cylinder 71 from the high pressure port Pin.

FIG. 9 shows a principle diagram of an axial piston motor, in which a working fluid pressurized and supplied to a high pressure port (not shown) is passed through an arcuate port PI or PII of a fixed valve plate 76 to form a plurality of cylinders in a cylinder block 77. By acting on the piston 78, the axial thrust generated in each piston 78 is converted into a rotational force by the fixed swash plate 79, and the output shaft 80 is rotated together with the cylinder block 77.

This axial piston motor has a valve plate 76
When the working fluid is introduced to one port PI of the cylinder block, the piston 78 positioned in the phases b to e is pressed against the swash plate 79 by the working fluid and tries to slide in the direction of the arrow I, so that the cylinder block is blocked.
77 and the output shaft 80 integrated therewith are rotated in the direction of arrow I. On the contrary, when the working fluid is guided to the port PII of the valve plate 76, the piston 78 positioned in the phases f to i tries to slip in the direction of arrow II and rotates the output shaft 80 in the direction of arrow II.

The vane motor and the gear motor have a simple structure, but the working fluid easily leaks under high load, and the characteristics at the time of starting and at low speed are not good. On the other hand, although the radial piston motor and the axial piston motor have complicated structures, they are suitable for applications requiring low speed rotation and have excellent starting torque.

The radial piston motor has a large size because a plurality of cylinders 71 are arranged in a star shape in the radial direction, whereas the axial piston motor has a large number of cylinders fitted in the axial direction of the cylinder block 77. Since the axial force of the piston 78 is converted into the rotational force by the swash plate 79, it is smaller and lighter than the radial piston motor.

[0010]

As described above, the axial piston motor has the advantages of generating maximum output at a low speed, rotating smoothly, and being relatively small and lightweight. Since the axial force of the piston 78 is converted into rotational force, the friction between the piston 78 and the swash plate 79 reduces the efficiency in converting the axial force into rotational force.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an axial piston motor having means for efficiently converting an axial force into a rotational force in place of a conventional swash plate. It is what

[0012]

According to a first aspect of the present invention, there is provided at least a motor body which is formed in a substantially cylindrical shape and is hermetically sealed, and at least one of which is axially rotatably fitted in the motor body. A cylinder block formed by concentrically forming three or more axial piston insertion holes, a plurality of pistons axially slidably fitted in the respective piston insertion holes of the cylinder block, and these pistons A distribution valve mechanism for sequentially supplying a working fluid, a cam mechanism provided on the other axial side in the motor body for converting the axial force of each piston into a rotational force of a cylinder block, and a central portion of the cylinder block. And an output shaft that is integrally provided in the motor body and protrudes outside the motor body.

According to a second aspect of the present invention, in the axial piston motor according to the first aspect, the distribution valve mechanism is integrally formed with the cylinder block on the outer peripheral surface of the valve body integrally provided with the motor body. A working fluid supply groove that rotatably fits the inner peripheral surface of the provided rotary valve body and receives a working fluid from the outside at the same axial position on one side and the other side of the outer peripheral surface of the valve body, A working fluid discharge groove for discharging the working fluid to the outside is provided in the circumferential direction, and working fluid supply / discharge holes for supplying / discharging the working fluid to / from each piston are opened on the inner peripheral surface of the rotary valve body, respectively, and the valve body The working fluid supply / discharge holes of the rotary valve body are opposed to either one of the working fluid supply groove and the working fluid discharge groove according to the rotation angle.

According to a third aspect of the present invention, in the axial piston motor according to the first aspect, the cam mechanism comprises:
A cylindrical cam body having a cam groove formed in a sinusoidal curve on the outer peripheral surface is provided integrally with the motor main body at the center of the motor main body, and a plurality of cylinder cams are axially provided along the outer peripheral surface of the cylindrical cam main body. Of the above-mentioned guide bodies are integrally projected, and a plurality of axial-direction moving bodies integrally connected to each piston are fitted between these guide bodies so as to be slidable in the axial direction. A roller-like cam follower that is rotatably supported by the above is rotatably fitted in the cam groove of the cylindrical cam body.

[0015]

According to the first aspect of the present invention, when the working fluid is supplied to the piston by the distribution valve mechanism and the piston is actuated in the axial direction, the axial force of the piston is converted into the rotational force by the cam mechanism. Therefore, the cylinder block moves in the rotational direction together with the piston, and the output shaft rotates and is output to the outside.

According to the invention described in claim 2, when the cylinder block rotates, the rotary valve body also rotates integrally.
The positional relationship of the working fluid supply / discharge holes of the rotary valve body with respect to the working fluid supply groove and the working fluid discharge groove of the valve body changes, and the working fluid is supplied from the working fluid supply groove to the piston located in the phase corresponding to the piston pushing stroke. While supplying pressure, the working fluid extruded by the piston positioned in the phase corresponding to the piston retracting stroke is discharged to the outside through the working fluid discharge groove.

According to the third aspect of the present invention, when the piston is extruded by the working fluid, the cam follower axially supported by the axial moving body integral with the piston moves in the cam groove of the cylindrical cam body simultaneously with the axial movement. Because of the rotational movement along the axis, the axial moving body applies a rotational force to the guide body while moving in the axial direction, and this rotational force is taken out from the output shaft via the cylinder block.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to an embodiment shown in FIGS. 1 is a sectional view taken along the line I-I in FIGS. 2 to 4, FIG. 2 is a sectional view taken along the line II-II in FIG. 1, and FIG. 3 is a sectional view taken along line III-III in FIG.
FIG. 4 is a sectional view taken along line IV-IV in FIG.

As shown in FIG. 1, a base 11 having a mounting flange 11a at the bottom and an O on the top of the base 11.
Cylindrical casing fitted with a ring 12 and fixed to the upper flange 11b of the base 11 with bolts 13.
14, a head base 17 fitted to the upper part of the casing 14 through an O-ring 15 and fixed by hexagon socket head bolts 16, and a valve head 19 fixed to the head base 17 by hexagon socket head bolts 18. Thus, the motor body 10 is formed in a substantially cylindrical shape and sealed.

The casing 14 has an oil plug 21 for injecting or discharging lubricating oil into the motor body 10.
And an oil window 22 made of transparent resin or the like for visually observing the oil level Oil in the motor body 10 from the outside.
And screw each.

A cylindrical cylinder block 23 is rotatably fitted in the upper half of the motor body 10. The cylinder block 23 has a center hole 23a at a lower end shaft portion 19b provided below the lower small diameter portion 19a of the valve head 19.
Is rotatably fitted in the ball bearing 24.

As shown in FIG. 3, five piston insertion holes 23b are axially bored in a concentric circle of the cylinder block 23, and each piston insertion hole of the cylinder block 23 is formed.
The pistons 25 are fitted in the respective 23b so as to be slidable in the axial direction. As shown in FIG. 1, the upper part of the connecting rod 26 is fitted in the center of each piston 25, and the connecting rod 26 is
The flange portion 26a is integrated with the collar 27 by locking it with a retaining ring 28.

A distribution valve mechanism 31 for sequentially supplying a pressurized working fluid (working air or working oil) to these pistons 25 is provided on the upper portion of the motor body 10. This distribution valve mechanism 31
As shown in FIGS. 1 and 2, the valve head 19 provided integrally with the motor body 10 is used as a valve body, and the outer peripheral surface of the lower small diameter portion 19a of the valve head 19 serving as the valve body, An inner peripheral surface of a valve rotor 32 as a rotary valve body is rotatably fitted. The valve rotor 32 is concentrically and integrally provided on the upper surface of the cylinder block 23 with hexagon socket head cap screws 33.

A working fluid supply port 34 and a working fluid discharge port (not shown) are provided on the outer peripheral surface of the upper portion of the valve head 19, while the lower small diameter portion 19a of the valve head 19 is provided.
As shown in FIG. 2, a working fluid supply groove 35 and a working fluid discharge groove 36 are circumferentially provided at the same axial position on one side and the other side of the outer peripheral surface.

The working fluid supply groove 35 is formed in correspondence with the piston pushing stroke, receives the working fluid through a working fluid supply hole 37 formed in the working fluid supply port 34 in the axial direction, and operates. The fluid discharge groove 36 is formed corresponding to the piston retracting stroke, and discharges the working fluid to the outside from a working fluid discharge port (not shown in the figure) via a working fluid discharge hole 38 formed in the axial direction. The upper end opening of the working fluid supply hole 37 is closed with a plug 37a after perforation.

On the other hand, a working fluid supply / discharge hole 39 for supplying / discharging the working fluid to / from each piston 25 is formed in the axial direction and the radial direction of the valve rotor 32 from the upper part of each piston insertion hole 23b of the cylinder block 23. The working fluid supply / discharge holes 39 are opened in the inner peripheral surface of the valve rotor 32, respectively. The outer peripheral side of the working fluid supply / discharge hole 39 bored in the radial direction is closed by a plug 39a after the bore is bored.

Each working fluid supply / discharge hole 39 of this valve rotor 32
2 faces either one of the working fluid supply groove 35 and the working fluid discharge groove 36 of the valve head 19 depending on the rotation angle of the valve rotor 32 as shown in FIG.

A cam mechanism 41 for converting the axial force of each piston 25 into the rotational force of the cylinder block 23 is provided in the lower half of the motor body 10.

As shown in FIGS. 1, 4 and 5,
The cam mechanism 41 includes a cylindrical cam body 42, a peripheral surface O-ring 43, and an end surface O-ring, which are formed in a central recess of the base 11 of the motor body 10.
It is fitted via 44, and is fixed integrally with hexagon socket head cap bolt 45. On the outer peripheral surface of the cylindrical cam body 42, there is provided a cam groove 42a formed in a sinusoidal curve as shown in FIG.

Furthermore, as shown in FIG. 4, on the lower surface of the cylinder block 23, rod-shaped rods as five guides are arranged concentrically in the circumferential direction along the outer peripheral surface of the cylindrical cam body 42. The yoke guide 46 is screwed in and is integrally provided in the axial direction along the outer peripheral surface of the columnar cam body 42 so as to project.

Between the respective yoke guides 46, five cross heads 47 as axial moving bodies integrally connected to each piston 25 via the connecting rod 26 are provided with concave grooves provided on both side surfaces thereof. It is fitted slidably in the axial direction at 47a.

A radial cam follower shaft 48a is fixed to each of the cross heads 47 by a nut 49 screwed to the shaft, and a roller-like cam follower 48 protruding inside the cross head 47 is rotatably supported. The cam follower 48 is rotatably fitted in the cam groove 42a of the cylindrical cam body 42.

In the cam mechanism 41, when the piston 25 is pushed out by the working fluid, the cam follower 48 axially supported by the cross head 47 integral with the piston 25 moves axially and simultaneously the cam of the cylindrical cam body 42 is cammed. Since the crosshead 47 makes a rotational movement along the groove 42a, the crosshead 47 gives a rotational force to the yoke guide 46 while moving in the axial direction to rotate the cylinder block 23 integrated with the yoke guide 46.
The center shaft 51 as the next output shaft provided integrally with the above is rotated.

A center shaft 51 is integrally fitted into a shaft hole 23c formed in the center of the cylinder block 23 via a key 52, and its flange portion 51a is engaged with the lower end edge of the shaft hole 23c. , The center shaft 51 is integrally formed in the center of the cylinder block 23 by tightening the nut 54 that is screwed with the screw shaft portion 51b at the upper end of the center shaft through the washer 53 engaged with the upper end edge of the shaft hole 23c. Fix it.

The lower portion of the center shaft 51 penetrates the center hole 42b of the cylindrical cam body 42, and the tip portion provided with the key groove 51c is projected to the outside of the base 11. A space between the lower part of the center shaft 51 and the base 11 is kept liquid-tight by an oil seal 55 fitted between them.

The axial load applied to the center shaft 51 is received by the thrust needle bearing 56 provided between the flange portion 51a and the upper surface of the cylindrical cam body 42, and the radial load is applied to the center shaft 51 and the cylindrical cam. Body
It is received by a radial needle bearing 57 and a ball bearing 58 provided between the inner peripheral surface of 42. The ball bearing 58 is fixed by a lock nut 59.

Next, the operation of the embodiment shown in FIGS. 1 to 5 will be described.

A working fluid (working air or working oil) is supplied from the working fluid supply port 34 of the distribution valve mechanism 31 to the upper surface of the piston 25 through the working fluid supply hole 37, the working fluid supply groove 35 and the working fluid supply / discharge hole 39. When the pistons 25 are pushed down by the fluid pressure by supplying by pressurizing, the axial force of each piston 25 causes the cam follower 48 of the cross head 47 and the cam groove 42a of the cylindrical cam body 42 to engage with each other in the cam mechanism 41. Is converted into rotational force. This rotational force is transmitted from the cross head 47 to the yoke guide 46, the cylinder block 23 integrated with the yoke guide 46 also rotates, and the center shaft 51 integrated with the cylinder block 23 also rotates. Therefore, the piston 25 rotates while moving up and down.

In the distribution valve mechanism 31, since the valve rotor 32 also integrally rotates when the cylinder block 23 rotates, the working fluid supply groove 35 and the working fluid discharge groove 36 of the valve head 19 are provided.
The positional relationship of the working fluid supply / discharge hole 39 of the valve rotor 32 with respect to is changed. The working fluid supplied under pressure from the working fluid supply port 34 through the working fluid supply hole 37 to the working fluid supply groove 35 formed in the region of the phase corresponding to the piston pushing stroke (down stroke) It acts on the two or three pistons 25 located in the phase corresponding to the stroke, and the working fluid is supplied and discharged by the two or three pistons 25 located in the phase corresponding to the piston retracting stroke (upstroke). The working fluid discharged into the hole 39 is discharged to the outside through the working fluid discharge hole 38 and the working fluid discharge port (not shown in the figure) from the working fluid discharge groove 36 formed in the phase region corresponding to the piston retracting stroke. Is discharged.

[0040]

According to the invention described in claim 1, the cam mechanism provided in the motor body converts the axial force of the piston into the rotational force of the cylinder block.
Rather than the swash plate in the conventional axial piston motor,
The axial force can be efficiently converted into a rotational force, and for example, a smooth rotational output can be obtained even by the pneumatic pressure used in a region where the supply pressure of the working fluid is significantly lower than the hydraulic pressure.

According to the second aspect of the invention, as a working fluid distribution valve mechanism, a working fluid supply groove and a working fluid discharge are provided on the outer peripheral surface of the valve body and the inner peripheral surface of the rotary valve body which are fitted to each other. Since the groove and the working fluid supply / discharge hole are opposed to each other, the working fluid leakage between the supply groove / discharge groove on the valve body side and the supply / discharge hole on the rotary valve body side is made possible by the simple peripheral surface fitting structure. Can be effectively suppressed.

According to the third aspect of the invention, an axially slidable axial movement is possible between the cam groove formed on the outer peripheral surface of the cylindrical cam body in a sinusoidal curve shape and the guide body projecting from the cylinder block. Since the roller-like cam follower provided on the body is fitted, the axial force can be efficiently converted into the rotational force, and the rotational force can be efficiently transmitted from the axial moving body to the cylinder block via the guide body. it can.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an axial piston motor according to the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a development view of an outer peripheral surface of a cylindrical cam body showing a cam groove shape of the cam mechanism.

FIG. 6 is a cross-sectional view showing a conventional vane motor.

FIG. 7 is a cross-sectional view showing a conventional gear motor.

FIG. 8 is a cross-sectional view showing a conventional radial piston motor.

9A is an explanatory view showing the principle of a conventional axial piston motor, and FIG. 9B is a front view showing a valve plate thereof.

[Explanation of symbols]

 10 Motor body 19 Valve head as valve body 23 Cylinder block 23b Piston insertion hole 25 Piston 31 Distribution valve mechanism 32 Valve rotor as rotary valve body 35 Working fluid supply groove 36 Working fluid discharge groove 39 Working fluid supply and discharge hole 41 Cam mechanism 42 Cylindrical cam body 42a Cam groove 46 Yoke guide as guide 47 Cross head as axial moving body 48 Cam follower 51 Center shaft as output shaft

Claims (3)

[Claims] 1. A motor body which is formed in a substantially cylindrical shape and is hermetically sealed, and at least three or more axial piston insertion holes which are rotatably fitted to one side in the motor body in the axial direction and are concentrically arranged. A bored cylinder block; a plurality of pistons axially slidably fitted in the piston insertion holes of the cylinder block; and a distribution valve mechanism for sequentially supplying a working fluid to these pistons, A cam mechanism provided on the other side in the axial direction of the motor body for converting the axial force of each piston into the rotational force of the cylinder block, and the cam mechanism integrally provided at the center of the cylinder block and projected to the outside of the motor body. And an output shaft, the axial piston motor. 2. A distribution valve mechanism, wherein an inner peripheral surface of a rotary valve body provided integrally with a cylinder block is rotatably fitted to an outer peripheral surface of a valve body integrally provided with a motor body, At the same axial direction position on the outer peripheral surface one side and the other side of the valve body,
A working fluid supply groove for receiving the working fluid from the outside and a working fluid discharge groove for discharging the working fluid to the outside are provided in the circumferential direction, and the working fluid is supplied to each piston on the inner peripheral surface of the rotary valve body. Each of the working fluid supply / discharge holes to be discharged is opened, and each working fluid supply / discharge hole of the rotary valve body is opposed to either the working fluid supply groove or the working fluid discharge groove of the valve body depending on the rotation angle. The axial piston motor according to claim 1, which is characterized in that. 3. A cam mechanism, wherein a cylindrical cam body having a cam groove formed in a sinusoidal curve on the outer peripheral surface is integrally provided with the motor body at the center of the motor body, and the cylinder block is connected to the cylindrical cam body. A plurality of guide bodies are integrally provided in the axial direction along the outer peripheral surface, and a plurality of axial moving bodies integrally connected to the pistons are fitted between the guide bodies so as to be slidable in the axial direction. 2. An axial piston motor according to claim 1, wherein a roller-like cam follower rotatably supported by each of the axial moving bodies is rotatably fitted in a cam groove of the cylindrical cam body. .