CN217355289U - Hydraulic anti-backlash coupling with automatic pressure adjustment function - Google Patents

Abstract

The utility model belongs to the technical field of mechanical parts and discloses a hydraulic anti-backlash coupler with automatic pressure adjustment, wherein a housing of the coupler is provided with a cavity; the first opening is sleeved in the cavity and is in limit connection with the shell through a clamping structure; the piston is inserted into the first opening sleeve and connected with the first opening sleeve, and a first pressure cavity is formed between the piston and the first opening sleeve; the first end cover is inserted in the cavity, sleeved on the piston and fixedly connected with the first opening sleeve, and a second pressure cavity is formed between the piston and the first end cover; the second open sleeve is sleeved on the piston, a spiral chute is arranged on the second open sleeve, a second connecting piece penetrates through the spiral chute, and the second connecting piece is fixed with the piston; the second end cover is sleeved on the piston and is fixedly connected with the shell; the first and second pressure control assemblies are in communication with the first and second pressure chambers, respectively. The utility model discloses a two-way zero clearance transmission of single nut screw drive pair, the practicality is high.

Description

Hydraulic anti-backlash coupling with automatic pressure adjustment function

Technical Field

The utility model relates to a machine parts technical field, in particular to pressure automatically regulated's hydraulic pressure gap shaft coupling that disappears.

Background

In a high-end precision numerical control machine tool which is widely used at present, in order to eliminate a reverse clearance which affects the transmission precision of a screw nut pair, a precision ball screw pair with a double-nut structure is one of main precision functional parts which are most frequently used, and the precision ball screw pair almost occupies most markets of precision transmission functional parts with good precision characteristics and the characteristic of long-term use.

However, the existing double-nut structure has a fatal defect, in order to eliminate the reverse gap, the double-nut screw pair is realized by adjusting the thickness of a gasket between the double nuts, and when the thickness of the gasket is too large, the load of the screw can be increased, the abrasion of the screw is accelerated, and the service life of the screw pair is reduced; when the thickness of the gasket is too small, the reverse clearance cannot be completely eliminated, so that the transmission precision is reduced; therefore, when a new lead screw leaves a factory, the lead screw and the gasket need to be matched and ground, which wastes time and labor; moreover, because the new lead screw product is frequently used only in a certain section of the lead screw stroke after being installed, after a period of time of use, the frequently used section is seriously worn, and the reverse clearance of the ball screw in the section of the stroke which cannot ensure the uniform use of the full stroke is inevitably larger than that of the section which is not frequently used; in this case, the reverse clearances at different positions of the same screw cannot be completely compensated for by either mechanical or electrical methods, and therefore, certain disadvantages are inevitably caused to the transmission accuracy of the ball screw assembly and cannot be eliminated at present. Once the excessive uneven wear occurs in a certain stroke of the screw, the whole machine tool transmission part needs to be disassembled, the screw is taken out, and the whole machine tool transmission part needs to be replaced integrally, so that high maintenance cost is brought.

In the single-nut ball screw transmission pair, besides increasing the interference between the balls and the raceways in the nut and adopting a point-by-point compensation mode of an electrical system, no method for better eliminating the reverse clearance exists, and the defects of the two methods are obvious.

SUMMERY OF THE UTILITY MODEL

The utility model provides a pressure automatically regulated's hydraulic pressure gap shaft coupling that disappears to overcome the problem that exists among the above-mentioned prior art.

The technical scheme of the utility model is that:

a hydraulic anti-backlash coupling with automatic pressure adjustment, comprising:

a housing, on which a cavity is opened;

the first opening sleeve is inserted into the cavity and is in limit connection with the shell through a clamping structure;

the piston is inserted into the first opening sleeve and connected with the first opening sleeve through a guide transmission structure, and a first pressure cavity is formed between the piston and the first opening sleeve;

the first end cover is inserted into the cavity, sleeved on the piston and fixedly connected with the first opening sleeve, and a second pressure cavity is formed between the first end cover and the piston;

the second opening sleeve is sleeved on the piston, a spiral sliding groove is formed in the second opening sleeve, a second connecting piece penetrates through the spiral sliding groove, and the second connecting piece is fixedly connected with the piston;

the second end cover is sleeved on the piston and is fixedly connected with the shell;

and the first pressure control assembly and the second pressure control assembly are respectively communicated with the first pressure cavity and the second pressure cavity and are used for injecting pressure medium into the first pressure cavity or the second pressure cavity to push the piston to move.

Preferably, the guide transmission structure includes:

the piston is characterized in that the piston comprises a circular boss arranged on the end face of the piston, an external spline is arranged on the outer circumference of the circular boss, the external spline is meshed with an internal spline on the first opening sleeve, and the internal spline is arranged in a groove on the first opening sleeve.

Preferably, the external splines are replaced by external straight-toothed gears and the internal splines are replaced by internal straight-toothed gears.

Preferably, the straight-tooth external gear is replaced by a helical-tooth external gear, the straight-tooth internal gear is replaced by a helical-tooth internal gear, and the spiral chute is replaced by a straight chute.

Preferably, the clamping structure comprises an annular boss arranged at one end of the first opening sleeve, the annular boss is clamped on a step groove, and the step groove is formed in the shell.

Preferably, a first planar thrust bearing is further arranged between the annular boss and the step groove, a second planar thrust bearing is arranged between the first end cover and the second end cover, and the second planar thrust bearing is sleeved on the second opening sleeve.

Preferably, at least one first sealing element is arranged between the first opening sleeve and the shell, a second sealing element is arranged between the first opening sleeve and the piston, a third sealing element is arranged between the piston and the first end cover, and a fourth sealing element is arranged between the first opening sleeve and the first end cover.

Preferably, the first pressure control assembly is identical in construction to the second pressure control assembly.

Preferably, the first pressure control assembly includes a first channel provided on the housing, one end of the first channel is communicated with the first pressure chamber, the other end of the first channel is provided with a first interface, the first interface is communicated with an external first pressure medium source, and a first pressure adjusting system for adjusting pressure of a medium in the first pressure chamber is provided between the first pressure medium source and the first interface.

Preferably, the first pressure regulating system comprises a first electro-hydraulic proportional overflow valve and a first pressure sensor, one end of the first electro-hydraulic proportional overflow valve is connected to an outlet of the first pressure medium source, the other end of the first electro-hydraulic proportional overflow valve is connected to one end of a first reversing valve, the other end of the first reversing valve is connected to the first interface, the first electro-hydraulic proportional overflow valve is further electrically connected to a first signal amplifier, the first signal amplifier and the first pressure sensor are in signal connection with an external controller, and the controller is electrically connected to the power supply through a control switch.

The utility model discloses a first pressure control subassembly pours into pressure medium into or the first pressure chamber of discharge into, pour into pressure medium into or the second pressure chamber of discharge through second pressure control subassembly, according to the pressure differential between the first pressure chamber of load condition control and the second pressure chamber, promote piston reciprocating motion, and the cooperation of the spiral spout of seting up and second connecting piece is sheathe in through the second opening, when the drive lead screw is in the reversal, produce a required in the twinkling of an eye, arbitrary angle's additional rotation, thereby can realize the vice two-way zero clearance transmission of single nut screw drive, reverse clearance in the vice transmission of single nut screw has been eliminated, and simultaneously, can also be according to the load situation of change, adjust the inside hydraulic pressure of piston at any time, rigidity when being used for guaranteeing the transmission.

Compared with the prior art, the utility model provides a pair of pressure automatically regulated's hydraulic pressure gap eliminating shaft coupling, its beneficial effect is:

1. the utility model can completely eliminate the reverse transmission clearance with any value at any reverse point, and can greatly improve the use precision of the single-nut lead screw with common precision grade if being matched with the pitch error compensation function of a numerical control system;

2. the pressure difference between the first pressure cavity and the second pressure cavity of the utility model can be pre-tensioned and adjusted in real time through the control system according to the load condition, thereby reducing the abrasion of the screw-nut pair in the use process and prolonging the service life of the screw-nut pair;

3. the utility model discloses the transmission precision of improvement system that can be very big, the transmission rigidity is good, and the practicality is strong, is worth using widely.

Drawings

Fig. 1 is a schematic structural view of the present invention;

FIG. 2 is a cross-sectional view of the present invention taken along line C-C;

fig. 3 is a cross-sectional view of the present invention taken along line D-D;

fig. 4 is a cross-sectional view of the invention taken along line E-E;

fig. 5 is a cross-sectional view of the present invention taken along line F-F;

fig. 6 is a G-G cross-sectional view of the present invention;

FIG. 7 is a first usage state diagram of the present invention;

fig. 8 is a second usage state diagram of the present invention.

Description of reference numerals:

1. a first connection end; 2. a first open sleeve; 3. a housing; 4. a first planar thrust bearing; 5. a first connecting member; 6. a first seal member; 7. a second seal member; 8. a fourth seal; 9. a first end cap; 10. a piston; 11. a second planar thrust bearing; 12. a third seal member; 13. a second end cap; 14. a second connecting member; 15. a second open sleeve; 16. a third connecting member; 17. a second connection end; 18. a first interface; 19. a second interface; 20. a straight chute.

Detailed Description

An embodiment of the present invention will be described in detail with reference to fig. 1 to 8 of the drawings, but it should be understood that the scope of the present invention is not limited by the embodiment.

Example 1

As shown in fig. 1, the hydraulic anti-backlash coupling with the automatic pressure adjustment function has a specific structure including a housing 3, wherein one end face of the housing 3 is provided with a cavity, the cross section of the cavity is stepped, a first open sleeve 2 is inserted into the stepped cavity, and the first open sleeve 2 is in limit connection with the housing 3 through a clamping structure.

Specifically, the clamping structure comprises an annular boss arranged at one end of the first opening sleeve 2, and the annular boss is clamped on a step groove formed in the shell 3, so that the first opening sleeve 2 is axially limited in a single direction.

A piston 10 is also inserted in the first open sleeve 2, the piston 10 is connected with the first open sleeve 2 through a guide transmission structure, and a first pressure cavity is formed between the piston 10 and the first open sleeve 2.

Specifically, the guide transmission structure comprises a circular boss arranged on the end face of the piston 10, an external spline is arranged on the outer circumference of the circular boss, the external spline is in meshed transmission connection with an internal spline on the first opening sleeve 2, and the internal spline is arranged in a groove on the first opening sleeve 2. The external splines are engaged with the internal splines, which can not only realize the transmission of circumferential rotation force on the first split sleeve 2 and the piston 10, but also allow the axial displacement of the first split sleeve 2 and the piston 10.

In addition, a first end cover 9 is sleeved on the piston 10, the first end cover 9 is inserted into the cavity and fixedly connected with the first opening sleeve 2 through screws, and a second pressure cavity is formed between the piston 10 and the first end cover 9.

As shown in fig. 1 and 6, a second open sleeve 15 is sleeved on one end of the piston 10 away from the first open sleeve 2, a spiral chute is formed in the second open sleeve 15, the cross section of the spiral chute is preferably trapezoidal, a second connecting piece 14 penetrates through the spiral chute, and the second connecting piece 14 is fixedly connected with the piston 10.

Preferably, the second connecting member 14 is a pin, and the cross section of the pin is a trapezoid matched with the cross section of the spiral chute, and the trapezoid is large at the top and small at the bottom, so that the second connecting member 14 can be conveniently inserted.

The first opening sleeve 2, the piston 10, the first end cover 9 and the shell 3 form a main body structure of the rotary oil cylinder, the second connecting piece 14 can move in the spiral sliding groove, and the spiral sliding groove is matched with the second connecting piece 14 to convert the linear movement of the piston 10 into the rotation of the rotary oil cylinder and provide additional rotation of any angle as required.

The piston 10 is sleeved with a second end cover 13, and the second end cover 13 is fixedly connected with the shell 3 to realize the sealing of the whole structure.

Further, a first pressure control assembly is communicated with the first pressure chamber and used for injecting or discharging pressure medium into or out of the first pressure chamber so as to push the piston 10 to move left and right. The second pressure chamber is communicated with a second pressure control assembly, the second pressure control assembly is used for injecting or discharging pressure medium into or out of the second pressure chamber, the first pressure chamber is injected or discharged with the pressure medium through the first pressure control assembly, the second pressure chamber is injected or discharged with the pressure medium through the second pressure control assembly, and the pressure difference between the first pressure chamber and the second pressure chamber is controlled to push the piston 10 to move left and right.

Preferably, a first plane thrust bearing 4 used for guaranteeing smooth proceeding of relative rotation is further arranged between the annular boss and the step groove, a second plane thrust bearing 11 used for guaranteeing smooth proceeding of relative rotation is arranged between the first end cover 9 and the second end cover 13, and the second plane thrust bearing 11 is sleeved on the second opening sleeve 15.

Preferably, as shown in fig. 1 and 3, two first sealing members 6 are disposed between the first split sleeve 2 and the housing 3, the two first sealing members 6 are disposed at intervals, a second sealing member 7 is disposed between the first split sleeve 2 and the piston 10, a third sealing member 12 is disposed between the piston 10 and the first end cap 9, and a fourth sealing member 8 is disposed between the first split sleeve 2 and the first end cap 9. The first seal 6, the second seal 7 and the third seal 12 may each preferably be a sealing rubber ring and the fourth seal 8 is preferably a non-metallic sealing gasket. The use of the first seal 6, the second seal 7, the third seal 12 and the fourth seal 8 makes the air tightness of the device good.

Preferably, the first pressure control assembly is identical in structure to the second pressure control assembly.

Preferably, the first pressure control assembly has a structure including a first passage opened in the housing 3, one end of the first passage is communicated with the first pressure chamber, as shown in fig. 4, the other end is provided with a first interface 18, the first interface 18 is communicated with an external first pressure medium source, and a first pressure adjusting system for adjusting the pressure of the medium in the first pressure chamber is arranged between the first pressure medium source and the first interface 18. The specific structure of the first pressure adjusting system comprises a first electro-hydraulic proportional overflow valve and a first pressure sensor, wherein one end of the first electro-hydraulic proportional overflow valve is connected with the outlet of a first pressure medium source, the other end of the first electro-hydraulic proportional overflow valve is connected with one end of a first reversing valve, the other end of the first reversing valve is connected with a first interface 18, the first electro-hydraulic proportional overflow valve is further electrically connected with a first signal amplifier, the first signal amplifier and the first pressure sensor are in signal connection with a peripheral controller, and the controller is electrically connected with a power supply through a control switch.

Preferably, the structure of the second pressure control assembly includes a second channel opened on the housing 3, one end of the second channel is communicated with the second pressure chamber, as shown in fig. 5, the other end is provided with a second interface 19, the second interface 19 is communicated with an external second pressure medium source, and a second pressure adjusting system for adjusting the pressure of the medium in the second pressure chamber is arranged between the second pressure medium source and the second interface 19. The second pressure adjusting system comprises a second electro-hydraulic proportional overflow valve and a second pressure sensor, wherein one end of the second electro-hydraulic proportional overflow valve is connected with an outlet of a second pressure medium source, the other end of the second electro-hydraulic proportional overflow valve is connected with one end of a second reversing valve, the other end of the second reversing valve is connected with a second interface 19, the second electro-hydraulic proportional overflow valve is further electrically connected with a second signal amplifier, and the second signal amplifier and the second pressure sensor are in signal connection with an external controller.

As a first alternative to the above, the external splines may be replaced by external straight toothed gears and the internal splines may be replaced by internal straight toothed gears. This also allows both the transmission of a circumferential rotational force on the first split sleeve 2 and the piston 10 and a slight axial displacement of the first split sleeve 2 and the piston 10.

As a second alternative to the above, as shown in fig. 8, the external straight-tooth gears are replaced with external helical gears, the internal straight-tooth gears are replaced with internal helical gears, and the spiral chutes are replaced with straight chutes 20. This also enables the transmission of a circumferential rotational force on the first split sleeve 2 and the piston 10, but also allows a slight axial displacement of the first split sleeve 2 and the piston 10.

The working principle of the utility model is further explained by taking the hydraulic anti-backlash coupler installed between the ball screw of the Z shaft of the numerically controlled lathe and the servo motor as an embodiment.

A hydraulic anti-backlash coupling with automatic pressure adjustment comprises a mechanical structure part:

the structure comprises a first split sleeve 2, a shell 3, a first end cover 9, a first plane thrust bearing 4, a piston 10, a second end cover 13, a second connecting piece 14 and a second split sleeve 15.

As shown in fig. 7, the first opening sleeve 2 is used to connect with the first connection end 1, as shown in the C-C sectional view shown in fig. 2, the first connection end 1 is inserted into the first opening sleeve 2, and when the first connection member 5 is screwed, the first opening sleeve 2 and the first connection end 1 can be fixedly connected through the first connection member 5.

Wherein, the first opening sleeve 2, the piston 10, the first end cover 9, the shell 3 and the structure form the main structure of the rotary oil cylinder, and the first opening sleeve 2 plays the role of the cylinder body of the rotary oil cylinder in the structure of the device.

The second connecting end 17 is inserted into the second opening sleeve 15 and connected with the second connecting end 17 through a third connecting piece 16, and specifically, the third connecting piece 16 is preferably a connecting bolt.

The first opening sleeve 2 is sleeved on the end 1 of the lead screw shaft and can be fixedly connected with the excircle of the end 1 of the lead screw shaft through the first connecting piece 5, the second connecting piece 14 is arranged on the piston 10, the second opening sleeve 15 with the spiral chute is fixedly connected with the second connecting end 17, and the spiral chute penetrates through the inner surface and the outer surface of the second opening sleeve 15.

In particular, the first connecting member 5 is preferably a bolt or other standard fastener.

The piston 10 is pushed to reciprocate by injecting pressure media with different pressures into two sides of the piston 10, the driving shaft and the driven shaft generate relative rotation by the gapless sliding of the second connecting piece 14 fixedly connected with the piston 10 along the spiral chute on the second open sleeve 15, and finally the purpose of eliminating the reverse gap during the transmission of the single-nut lead screw is achieved.

The hydraulic anti-backlash coupling comprises an electrical control part:

the first pressure control assembly and the second pressure control assembly are identical in structure, wherein the first pressure control assembly comprises a first channel arranged on the housing 3, one end of the first channel is communicated with the first pressure cavity, the other end of the first channel is provided with a first interface 18, the first interface 18 is communicated with an external first pressure medium source, and a first pressure adjusting system used for adjusting the pressure of the medium in the first pressure cavity is arranged between the first pressure medium source and the first interface 18. The specific structure of the first pressure adjusting system comprises a first electro-hydraulic proportional overflow valve and a first pressure sensor, wherein one end of the first electro-hydraulic proportional overflow valve is connected with the outlet of a first pressure medium source, the other end of the first electro-hydraulic proportional overflow valve is connected with one end of a first reversing valve, the other end of the first reversing valve is connected with a first interface 18, the first electro-hydraulic proportional overflow valve is further electrically connected with a first signal amplifier, the first signal amplifier and the first pressure sensor are in signal connection with a peripheral controller, and the controller is electrically connected with a power supply through a control switch.

Preferably, the structure of the second pressure control assembly includes a second channel provided on the housing 3, one end of the second channel is communicated with the second pressure chamber, the other end of the second channel is provided with a second interface 19, the second interface 19 is communicated with an external second pressure medium source, and a second pressure adjusting system for adjusting the pressure of the medium in the second pressure chamber is provided between the second pressure medium source and the second interface 19. The second pressure adjusting system specifically comprises a second electro-hydraulic proportional overflow valve and a second pressure sensor, one end of the second electro-hydraulic proportional overflow valve is connected to the outlet of the second pressure medium source, the other end of the second electro-hydraulic proportional overflow valve is connected with one end of a second reversing valve, the other end of the second reversing valve is connected with a second interface 19, the second electro-hydraulic proportional overflow valve is further electrically connected with a second signal amplifier, and the second signal amplifier and the second pressure sensor are in signal connection with an external controller.

The utility model discloses a theory of operation:

as shown in fig. 1, the hydraulic anti-backlash coupler of the present invention is installed at the installation position of the original coupler, and then the first connecting member 5 and the third connecting member 16 are used to fix the second opening sleeve 15 and the first opening sleeve 2 at the shaft end of the servo motor and the shaft end of the lead screw respectively; then, hydraulic oil with different pressures is respectively injected into a first pressure cavity and a second pressure cavity at two ends of the piston 10 through a pressure medium injection/discharge first interface 18 or a second interface 19, the hydraulic anti-backlash coupling drives the screw rod to rotate for an angle, and the driving edge of the screw rod raceway pushes the balls to tightly lean against the driven edge of the nut raceway without gaps; when the servo motor drives the lead screw to rotate reversely, firstly, when the servo motor decelerates to stop, the servo motor can keep the stop state under the action of a numerical control system of a machine tool, meanwhile, a control system can send a reverse signal to the servo motor, a control system of the coupler can simultaneously receive the reverse signal, and the reverse signal can control the electro-hydraulic proportional reversing overflow valve to complete all actions of switching the coupler from pressure to driving the lead screw to rotate for a certain angle within tens of milliseconds; since the servo motor is kept in a relative static state under the action of an enabling (rotation/keeping allowing) signal of a numerical control system of the machine tool, the relative rotation of the two ends of the hydraulic anti-backlash coupling is only possible to be the rotation of the screw shaft. Once the control system of the electric part of the hydraulic anti-backlash coupling receives a reverse signal, the pressure is immediately switched to change the low-pressure end into a high-pressure end, so that the piston 10 and the second connecting piece 14 are pushed to slide along the spiral chute on the second open sleeve 15, the screw shaft rotates relative to the stationary motor shaft, and the driving edge of the screw raceway pushes the balls to tightly lean against the driven edge of the nut raceway without clearance. Once the roller path and the ball are in gapless contact, motion resistance is generated for the rotation of the screw rod, so that the hydraulic pressure for pushing the piston to move is increased, a control signal is triggered, the oil inlet hole is sealed (or the hydraulic pressure on two sides of the piston is the same), and the rotation of the screw rod shaft is stopped and kept unchanged at the position. As can be seen from FIG. 7, at this time, if the driving motor drives the screw rod to rotate clockwise, so that the section of the raceway shown in FIG. 7 moves leftwards, the raceway of the screw rod pushes the nut through the balls and moves leftwards at the same time, and gapless transmission is realized; when the screw rod moves reversely, in a tiny time period of tens of milliseconds before the motor drives the screw rod to rotate anticlockwise and the cross section of the raceway moves rightwards as shown in fig. 7, the pressures on both sides of the piston 10 are adjusted by the first pressure control assembly and the second pressure control assembly, the piston 10 pushes the screw rod to rotate anticlockwise, the screw rod pushes the balls to move along the screw spiral raceway to the right side of the screw raceway in fig. 7 until the balls abut against the right side of the screw raceway, at this time, the motor does not start to rotate anticlockwise, and is in a feed holding (rotation locking) stage, at this time, as long as the moving distance of the screw raceway caused by the rotation angle of the screw rod due to the movement stroke of the piston does not exceed a reverse clearance, the position of the moving part (workbench) does not change, and at this time, the screw raceway and the balls, the three nut raceways are kept in close contact; therefore, if the driving motor starts to drive the screw to rotate counterclockwise, and the section of the raceway moves rightward as shown in fig. 7, the raceway of the screw directly pushes the nut through the balls and moves rightward at the same time, and the transmission is also gapless.

Therefore, the reversing of the screw driven by hydraulic pressure is firstly completed within a time period of tens of milliseconds during the rotation reversing of the screw, so that the transmission of the single-nut screw pair is ensured to be the transmission without reverse gaps; at this time, the screw rod does not start to drive the nut to move, so that the relative position of the transmission pair is kept unchanged. In addition, when the ball screw drive nut is in a state of continuously moving towards a certain direction, because the first port 18 or the second port 19 of the inlet/outlet of the piston is in a closed state, when the force applied to the two sides of the piston is unbalanced due to the change of the movement load, the hydraulic media sealed on the two sides of the piston generate opposite acting forces to restore the balanced state of the two ends of the piston.

The feasibility conclusion of this embodiment can be examined as to whether it is correct by the following calculation.

From Newton's second law, F ═ ma, the same principle applies

Mn＝ε*I＝Ft*2R (1)

Then epsilon is Ft 2R/I (2)

In the above formula, Mn is a torque generated when the conical pin is driven by hydraulic pressure to move in the spiral chute to drive the screw rod to rotate;

epsilon is the angular acceleration of the lead screw and the coupler fixedly connected with the lead screw when the lead screw rotates in a clearance eliminating way;

i is the moment of inertia of the lead screw (including the coupler) during anti-backlash rotation,

I＝(m1*r1 ² +m2r2 ² )/2 (3)

m1 is the total mass of the screw as it rotates;

m2 is the mass of the co-moving coupling;

r1 is the radius of rotation of the lead screw;

r2 is the turning radius of the coupling;

the driving force F for driving the conical pins to move along the spiral line direction of the spiral chute can be divided into an axial component Fr and a circumferential component Ft, and when 2 conical pins are uniformly stressed, the conical pins are uniformly stressed

Fr＝p*S/2 (4)

Ft＝Mn/2R； (5)

Ft/Fr＝tanθ； (6)

Wherein the content of the first and second substances,

p is the pressure difference of the pressure medium acting on both ends of the piston;

s is the piston area acted on by the pressure medium:

theta is the helix angle of the helical chute;

r is the radius of a stress point of a contact surface of the conical pin and the sliding chute for driving the lead screw to rotate;

according to newton's law of kinematics, the angular velocity and the angle of rotation of the rotor are related as follows:

ω＝ε*t

wherein the content of the first and second substances,

phi is the angle which needs to be rotated when the screw rod rotates in a clearance eliminating way;

epsilon is the angular acceleration of the lead screw during the anti-backlash rotation;

t is the time length for the gap eliminating rotation of the screw rod;

assuming that the back clearance at the lead screw reversal point is Δ L and the angle of rotation required to remove Δ L the lead screw is φ, the following holds according to the similar triangle theorem:

ΔL/φ＝h/2π (8)

phi is equal to delta L2 pi/h (9)

Wherein, the first and the second end of the pipe are connected with each other,

h is the lead of the lead screw;

epsilon is the angular acceleration of the screw rod during gap eliminating rotation;

t is the time length for the gap eliminating rotation of the screw rod;

as can be seen from the above formula, when the influence of the movement resistance is not considered,

if delta L is 0.1mm (when a test screw (model 4016, nominal diameter 40mm, lead 16mm and length 1000mm) is assembled, the factory clearance is 0.1mm, the mass of the screw is 10kg), the turning radius of a conical pin of the coupler is 20mm, the total mass of the coupler is 0.6kg, the stress area S of a piston is 1.0446 x 10-3m2, and the helix angle of the spiral chute is less than 4 degrees of the sliding self-locking angle.

As can be seen from equation (10):

that is, when the pressure difference between both ends of the piston is 0.25MPa, T is 67.2 ms.

It should be noted that this result does not take into account the frictional resistance as the lead screw rotates and the hydraulic valve switching frequency.

The pressure of a hydraulic station which is configured by a numerical control machine tool in a standard mode and uses a ball screw transmission pair at present can reach more than 3.5MPa, the reverse rotation starting time is about 50-100 ms, the action frequency of a known reversing valve is up to 120Hz, namely about 8.3ms, and T is 75.5 ms.

Therefore, the result of the simple calculation shows that the utility model can be applied to the lead screw with the nominal diameter less than or equal to 40mm and the length less than 1000 mm.

According to the formula (10), when the coupler is used for lead screw products of other specifications, the maximum duration requirement required by the anti-backlash rotation can be met by properly adjusting the piston area of the hydraulic anti-backlash coupler and the oil supply pressure of hydraulic oil due to the fact that the time for the anti-backlash rotation is in inverse proportion to the piston area and the pressure of a pressure medium.

In addition, it can be known from the formula (10) that the hydraulic pressure required for driving the nut to perform the backlash elimination movement is directly proportional to the mass of the nut, inversely proportional to the action area of the pressure medium on the piston, and inversely proportional to the square of the time t required for the nut to perform the backlash elimination movement.

The time for eliminating the clearance of the coupler can be controlled within 50-100 ms, so that the machining error caused by nut stagnation when the screw rod is reversed due to the reverse clearance can be avoided in the process of reversing the screw rod.

In addition, as can be seen from fig. 1 and 7, when the coupling drives the lead screw to rotate, even if the pressure sensor fails to close the oil supply line in time, the rotation of the drive lead screw is stopped by controlling the stroke end point of the coupling piston. Therefore, as long as the time required by the anti-backlash rotation is less than 50ms by properly adjusting the parameters of the coupler and increasing the area of the piston, the stroke of the piston can be controlled by adjusting the mechanical structure, so that the aim of eliminating the reverse clearance of the single-nut ball screw is fulfilled, and the transmission of the driving force of the screw is finally transmitted to a load through the screw raceway-ball-nut raceway.

Additionally, the utility model discloses the product is owing to adopt the pressure medium's of piston both sides pressure value change to control the lead screw and carry out reverse clearance's elimination motion, consequently, because the temperature influence in the lead screw working process, when producing new pitch error when taking place length change, hydraulic system also can compensate automatically. Therefore, the pretensioning work of the lead screw is not required.

In addition, when needs are adapted to the situation of inclined axis or vertical axis, the utility model provides a hydraulic pressure anti-backlash shaft coupling's the area of force receiving of piston 10 both sides can be different.

Compared with the prior art, the utility model provides a pair of pressure automatically regulated's hydraulic pressure crack shaft coupling that disappears, the pressure differential of the pressure medium through the piston both sides injection in adjustment and the rotatory hydro-cylinder of lead screw fixed connection, promote piston reciprocating motion, and through fixing the round pin axle of piston tip and with it the spout on the sliding sleeve outer ring of complex and motor shaft fixed connection's shaft coupling, the drive screw is when the reversal, produce a required in the twinkling of an eye, the additional rotation of arbitrary angle, thereby can realize the vice two-way zero clearance transmission of single nut lead screw transmission, reverse clearance in the vice transmission of single nut lead screw has been eliminated, high practicability, and is worth promoting.

The above disclosure is only for a few specific embodiments of the present invention, however, the present invention is not limited to the embodiments, and any changes that can be considered by those skilled in the art shall fall within the protection scope of the present invention.

Claims (10)

1. The utility model provides a pressure automatically regulated's hydraulic pressure gap eliminating shaft coupling which characterized in that includes:

a shell (3) which is provided with a cavity;

the first opening sleeve (2) is inserted into the cavity and is in limit connection with the shell (3) through a clamping structure;

the piston (10) is inserted into the first open sleeve (2) and connected with the first open sleeve (2) through a guide transmission structure, and a first pressure cavity is formed between the piston (10) and the first open sleeve (2);

the first end cover (9) is inserted into the cavity, sleeved on the piston (10) and fixedly connected with the first opening sleeve (2), and a second pressure cavity is formed between the first end cover (9) and the piston (10);

the second opening sleeve (15) is sleeved on the piston (10), a spiral sliding groove is formed in the second opening sleeve (15), a second connecting piece (14) penetrates through the spiral sliding groove, and the second connecting piece (14) is fixedly connected with the piston (10);

the second end cover (13) is sleeved on the piston (10) and is fixedly connected with the shell (3);

and the first pressure control assembly and the second pressure control assembly are respectively communicated with the first pressure cavity and the second pressure cavity and are used for injecting pressure medium into the first pressure cavity or the second pressure cavity to push the piston (10) to move.

2. The hydraulic anti-backlash coupling of claim 1, wherein said guided drive structure comprises:

set up circular boss on piston (10) terminal surface, the outer spline has been seted up on the outer circumference of circular boss, the outer spline with the internal spline meshing on first opening cover (2), the internal spline sets up in the recess on first opening cover (2).

3. The automatic pressure adjusting hydraulic anti-backlash coupling of claim 2, wherein the external splines are replaced by external straight teeth gears and the internal splines are replaced by internal straight teeth gears.

4. The hydraulic anti-backlash coupling with automatic pressure adjustment according to claim 3, wherein the external straight-tooth gears are replaced by external helical gears, the internal straight-tooth gears are replaced by internal helical gears, and the helical chutes are replaced by the straight chutes (20).

5. The hydraulic anti-backlash coupling with automatic pressure regulation according to claim 1, wherein the clamping structure comprises an annular boss arranged at one end of the first open sleeve (2), the annular boss is clamped on a stepped groove, and the stepped groove is arranged in the housing (3).

6. The hydraulic anti-backlash coupling with the automatic pressure regulation function according to claim 5, wherein a first plane thrust bearing (4) is further arranged between the annular boss and the step groove, a second plane thrust bearing (11) is arranged between the first end cover (9) and the second end cover (13), and the second plane thrust bearing (11) is sleeved on the second opening sleeve (15).

7. A pressure self-adjusting hydraulic anti-backlash coupling according to claim 1, wherein at least one first seal (6) is arranged between the first split sleeve (2) and the housing (3), a second seal (7) is arranged between the first split sleeve (2) and the piston (10), a third seal (12) is arranged between the piston (10) and the first end cap (9), and a fourth seal (8) is arranged between the first split sleeve (2) and the first end cap (9).

8. The self-adjusting pressure hydraulic anti-backlash coupling of claim 1, wherein said first pressure control assembly is identical in construction to said second pressure control assembly.

9. The hydraulic anti-backlash coupling with automatic pressure regulation according to claim 8, wherein the first pressure control assembly comprises a first channel opened on the housing (3), one end of the first channel is communicated with the first pressure chamber, the other end of the first channel is provided with a first interface (18), the first interface (18) is communicated with an external first pressure medium source, and a first pressure regulation system for regulating the pressure of the medium in the first pressure chamber is arranged between the first pressure medium source and the first interface (18).

10. The hydraulic anti-backlash coupling with the automatic pressure regulation function as claimed in claim 9, wherein the first pressure regulation system comprises a first electro-hydraulic proportional overflow valve and a first pressure sensor, one end of the first electro-hydraulic proportional overflow valve is connected to an outlet of a first pressure medium source, the other end of the first electro-hydraulic proportional overflow valve is connected to one end of a first reversing valve, the other end of the first reversing valve is connected to the first interface (18), the first electro-hydraulic proportional overflow valve is further electrically connected to a first signal amplifier, the first signal amplifier and the first pressure sensor are in signal connection with an external controller, and the controller is electrically connected to a power supply through a control switch.

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