Variable throttle hydrostatic bearing

Abstract

A variably throttleable hydrostatic bearing comprising: a hydrostatic pocket (2a, 2c, 5a) formed in a bearing surface (2); a fluid supply device (11) supplying a fluid to the hydrostatic pocket (2a, 2c, 5a); a fluid channel (4) forming a channel for a fluid extending from the fluid supply device (11) to the hydrostatic pocket (2a, 2c, 5a); a variable throttle (3) provided in the center of the fluid channel (4) which throttles the flow rate of the fluid so that the fluid is introduced into the hydrostatic pocket (2a, 2c, 5a), wherein the variable throttle (3) comprises: a fluid storage chamber (32a); a fluid supply chamber (31a) with a projecting section (31b) in its central section;a diaphragm (33) separating the fluid supply chamber (31a) from the fluid storage chamber (32a) and in which a surface of the diaphragm (33) faces the projecting section (31b) perpendicular to a direction of the thickness of the diaphragm (33) via a predetermined gap (t2), and a channel (31c) provided in the projecting section (31b) and connected to the hydrostatic pocket (2a, 2c, 5a), wherein the variable throttle (3) sets a throttling amount by using a degree of opening of the gap (t2) between the diaphragm (33) and the projecting section (31b), a piston, a cylinder (32b) which receives the piston (34) in such a way that the piston (34) is displaceable, and together with the piston (34) forms a fluid chamber (32c);characterized in that the piston at its first end (34c) comes into contact with a surface on the side of the diaphragm (33) which is opposite the surface which faces the projecting section (31b); and the variable throttle (3) has an elastic element (35) which is received in the cylinder (32b) and presses a second end of the piston (34).

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The invention relates to a variably throttleable hydrostatic bearing with a variable throttle of the diaphragm type. 2. Description of the associated technology

[0002] According to an associated technology, a variably throttled hydrostatic bearing with a variable throttle of the diaphragm type has a variable throttle section in a central section of a diaphragm surface that is perpendicular to the direction in which the diaphragm is movable. This is intended to enhance the vibration damping effect of the diaphragm for damping vibrations in a fluid circuit that includes a hydrostatic pocket and the variable throttle. In the variably throttled hydrostatic bearing, a gap is formed between an outer circumferential section of the diaphragm and a diaphragm retaining element. This gap represents a small space and is filled with a hydrostatic fluid to suppress diaphragm vibration (see Fig. 7 of the Japanese patent disclosure no. H10-196655 (JP H10-196655 A)).

[0003] The displacement of the membrane is greatest in its central section and small in its edge section, and therefore, in the associated technology described in JP H10-196655 A, the displacement in the edge section of the membrane, which contributes to suppressing the vibration, is small, which may make it difficult to generate a sufficient damping effect. SUMMARY OF THE INVENTION

[0004] It is an object of the present invention to provide a variably throttleable hydrostatic bearing with a variable diaphragm-type throttle, which makes it possible to easily achieve a desired damping capability by arranging a damping mechanism at a desired position.

[0005] According to one aspect of the present invention, a variably throttleable hydrostatic bearing has the following characteristics: a hydrostatic pocket formed in a storage area; a fluid supply device that supplies a fluid to the hydrostatic pocket; a fluid channel that forms a conduit for a fluid extending from the fluid supply device to the hydrostatic pocket; and a variable throttle that is provided in the middle of the fluid channel and throttles the flow of fluid in order to introduce the fluid into the hydrostatic pocket.

[0006] The variable throttle has a fluid storage chamber, a fluid supply chamber with a projecting section in its central portion, a diaphragm separating the fluid supply chamber from the fluid storage chamber, and in which a surface of the diaphragm, perpendicular to a direction of the diaphragm's thickness, faces the projecting section via a predetermined gap, and a channel provided in the projecting section that connects to the hydrostatic pocket. The variable throttle adjusts the throttle amount by varying the degree of opening of the gap between the diaphragm and the projecting section.

[0007] The variably throttleable hydrostatic bearing also features the following: a piston which at its first end comes into contact with a surface on the side of the membrane that is opposite to the surface facing the projecting section; a cylinder that accommodates the piston in such a way that the piston is movable and, together with the piston, forms a fluid chamber; and an elastic element that pushes a second end of the piston and is contained within the cylinder.

[0008] In the case of the variably throttleable hydrostatic bearing according to the previously described point of view, the cylinder can be closed at its first end and a fluid in the fluid chamber flows into and out of the cylinder via a gap between the piston and an inner circumferential surface of the cylinder.

[0009] In the variable-throttle hydrostatic bearing, as described above, the viscosity resistance of the fluid flowing out of the fluid chamber impedes the movement of the diaphragm in one direction, away from the protruding section. When the fluid circuit with the hydrostatic pocket and the variable throttle oscillates, and the diaphragm oscillates in the direction of its thickness, a damping effect is provided to prevent diaphragm oscillation. The piston is separate from the diaphragm and can therefore be positioned at a desired location on the surface of the diaphragm opposite the surface facing the protruding section. This enables a variable-throttle hydrostatic bearing that simplifies the adjustment of the desired damping effect.

[0010] In the case of the variably throttleable hydrostatic bearing according to the previously described point of view, the piston can have sections with a large diameter at opposite ends of a section with a small diameter in one axial direction.

[0011] The variable-throttling hydrostatic bearing, as described above, allows for individual adjustment of the sum of the axial lengths of the large-diameter piston sections and the maximum axial distance between the ends of these sections. The sum of the axial lengths of the large-diameter sections affects the viscosity resistance. The maximum axial distance between the ends of the large-diameter sections affects the piston's angular deflection. Because the sum of the axial lengths and the maximum axial distance can be individually adjusted, a variable-throttling hydrostatic bearing can be provided that prevents excessive piston angular deflection and allows for optimal adjustment of the viscosity resistance.

[0012] In the case of the variably throttleable hydrostatic bearing according to the previously described point of view, the first end of the piston can have a smaller cross-sectional area than the large diameter sections of the piston.

[0013] The variably throttled hydrostatic bearing, as described above, allows for a reduction in the contact area between the piston and the diaphragm, thereby increasing the contact pressure. This prevents the formation of a fluid film in the contact area. A fluid film can impair the response to a resisting force and thus reduce the damping effect. Therefore, preventing the formation of the fluid film improves the damping effect. Consequently, a variably throttled hydrostatic bearing with an improved damping effect can be provided.

[0014] In the case of the variably throttleable hydrostatic bearing according to the previously described point of view, a section of the diaphragm that does not face the protruding section may have a channel that connects the fluid supply chamber and the fluid storage chamber.

[0015] In the variable-throttling hydrostatic bearing, as described above, the diaphragm incorporates the channel connecting the fluid supply chamber and the fluid storage chamber, eliminating the need for an external channel. This simplifies the design of the variable throttle, allowing for the cost-effective manufacture of the variable-throttling hydrostatic bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The preceding and further features and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings, wherein the same reference numerals are used to represent the same elements, and wherein:

[0017] Fig. 1 is a schematic diagram representing a general configuration of a table conveyor according to the present embodiment;

[0018] Fig. 2 a sectional view along line AA from Fig. 1 shows;

[0019] Fig. 3 a detailed diagram of a variable throttle in a section B of Fig. 2 shows;

[0020] Fig. 4 shows a detailed diagram of a piston section;

[0021] Fig. 5 shows a detailed diagram of a variable throttle in one variation; and

[0022] Fig. 6 a diagram of the variable throttle seen in one direction of an arrow C from Fig. 5 shows. DETAILED DESCRIPTION OF EXAMPLES OF EXECUTION

[0023] An embodiment of the present invention is described, in which, as an example, the present invention is used for a table conveyor device.

[0024] As in Fig. As shown in 1, it has a table-top loading device. 1 a table 2 , which is attached to a sliding section of a base 10 It is mounted in a sliding manner, and it is a pair of back plates. 5 has, which are located at the lower sections of opposite ends of the table 2 are attached so that the table 2 It can only be moved in one X-axis direction.

[0025] As in Fig. As shown in section 2, there are two hydrostatic pockets. 2a in a storage area of ​​the table 2trained, who are the basis 10 are oriented in such a way that the hydrostatic pockets 2a Open downwards. A pair of hydrostatic pockets. 2c , which are facing each other in a transverse direction, is also in a storage area of ​​the table 2 trained. Variable throttles 3 are equipped with hydrostatic bags 2a and 2c in connection. An oil pipeline 4 is compatible with each of the variable throttles 3 in connection. A pump 11 (Fluid feeder) is used to feed a fluid to the oil supply line 4 coupled.

[0026] The backplates 5 They also have hydrostatic pockets 5a , which open upwards. The variable throttles 3 are equipped with hydrostatic bags 5a in connection. The oil pipeline 4 is compatible with each of the variable throttles 3 in connection.

[0027] Fig. 3 shows the variable throttle 3 in detail. The variable throttle 3 has a variable-throttle basis 31 with a fluid supply chamber 31a , and a lid 32 with a fluid storage chamber 32a , so that the fluid supply chamber 31a and the fluid storage chamber 32a are facing each other and form an outer circumferential section of the membrane 33 between the variable-throttle base 31 and the lid 32 It is intermediate. The variable-throttle basis 31 has an excellent section 31b and a delivery connection 31c , both of which are located in a central section of the fluid supply chamber 31a are located. The lid 32 has a cylinder 32b , which is a cylindrical blind hole, in a central section of the fluid storage chamber 32a A piston 34 is inside the cylinder 32bMounted in a sliding position. A coil spring. 35 is compressible inside a fluid chamber 32c , which the piston 34 and the cylinder 32b has, arranged so that the piston 34 towards the membrane 33 is pressed. This pressing force pushes the piston. 34 against the membrane 33 .

[0028] If the membrane 33 If it is in a neutral position, then the protruding section 31b and the membrane 33 facing each other across a gap t2. The oil supply line 4 is with the fluid storage chamber 32a through one in the lid 32 trained channel 32d in connection. The oil pipeline 4 is connected to the fluid supply chamber 31a through one in the variable-throttle base 31 trained channel 31d and the canal 32d in connection. The delivery connection31c is with the hydrostatic bag 2a through an inlet 2b in the table 2 in connection.

[0029] Based on Fig. 4. Details of the piston will be given. 34 described.

[0030] The piston 34 has a section 34b with small diameter and sections 34a with a large diameter, located at opposite ends of the section 34b with a small diameter relative to its axial direction. The present embodiment has two sections. 34a with a large diameter. The piston 34 has also ended 34c , the one with the membrane 33 is in contact. The two sections 34a Those with a large diameter have a diameter D2. The section 34b With a small diameter, it has a diameter that is approximately 80% of the diameter D2 of the sections. 34ais set with a large diameter. The end 34c has a diameter that is equal to or less than 50% of the diameter D2 of the sections 34a is set with a large diameter. The section 34a with a large diameter, extending from the end 34c further away, has a length L1, and the section 34a with a large diameter, closer to the end 34c The section lies and has a length L2. 34b With a small diameter, it has a length L3.

[0031] Based on Fig. Section 3 describes the functioning of the variably throttleable hydrostatic bearing.

[0032] If through the line 4 When a fluid is supplied, a fluid storage chamber is created 32a filled with the fluid that flows through the channel 32d has flowed. Furthermore, the fluid chamber 32cfilled with the fluid that passes through the gap (the throttle) between the insertion sections of the cylinder 32b and the piston 34 has flowed. On the other hand, the fluid supply chamber 31a filled with the fluid that flows through the channel 32d and the canal 31d has flowed. The fluid in the fluid supply chamber 31a flows across a gap between the membrane 33 and the outstanding section 31b and the delivery connection 31c into the hydrostatic bag 2a The fluid in the hydrostatic bag 2a flows through a gap between the hydrostatic pocket 2a and the base 10 , which represents an interval t1.

[0033] This also happens in hydrostatic pockets. 2c , which are located in a horizontal direction of the table 2 open, and in the hydrostatic pockets 5a in the backplate 5As a result, the basis 10 and the table 12 held by the gap t1, which passes through each of the hydrostatic pockets 2a is defined.

[0034] If the membrane 33 from the outstanding section 31b When the membrane is moved away, it presses down. 33 the piston 34 , which then goes into the cylinder 32b is pressed so that the volume of the fluid chamber increases. 32c The fluid decreases. Consequently, the fluid flows out of the fluid chamber. 32c via the gap (the throttle) between the insertion sections of the piston 34 and the cylinder 32b out. Thus, the piston 34 subject to a force that causes a piston displacement rate 34 The force is reduced due to the viscosity resistance of the fluid flowing between the insertion sections. The force is then applied to the membrane. 33 transferred and a displacement rate of the membrane 33will also be reduced.

[0035] When a fluid circuit, which has the hydraulic pockets and the variable throttles, oscillates, then the diaphragm acts 33 so that it oscillates, and the viscosity resistance acts on the piston. 34 to prevent oscillation. That is, the variable throttle provides a damping effect.

[0036] If the membrane 33 on the other hand, closer to the outstanding section 31b If it is displaced, then one of the pistons will be affected. 34 The deceleration force does not act on the membrane. 33 transferred. That is, the displacement rate of the membrane. 33 will not be reduced.

[0037] To improve the damping effect, it is effective that when the membrane 33 from the outstanding section 31b is displaced, the membrane 33 and the piston 34are constantly in contact with each other, thus maximizing the time in which damping occurs. Even if the membrane 33 closer to the outstanding section 31b The piston must be moved 34 at the right time for the displacement of the membrane 33 to achieve this, the oscillation frequency of a vibration system that drives the piston can be adjusted. 34 and the coil spring 35 exhibits a higher frequency than the oscillation frequency of the membrane 33 to be adjusted, or the mass of the piston 34 and the compressive force of the coil spring 35 can be adjusted so that the acceleration of the piston 34 higher than the maximum acceleration of the membrane's vibration 33 is.

[0038] As in Fig. As shown in section 4, in the present embodiment the section 34bwith the small diameter, which has a diameter that is approximately 80% of the outer diameter D2 of the sections 34a with a large diameter, in the middle of the piston 34 provided with regard to the axial direction, and the sections 34a Large diameter elements, which produce a throttling effect, are located at opposite ends of the section. 34b with a small diameter. This achieves the desired throttling characteristic and facilitates the operation of the piston. 34 It is made more stable. The throttling property is determined by using as a parameter the dimension D1 – D2 of a gap, which is the difference between the bore diameter D1 of the cylinder. 32b and the outer diameter D2 of the sections 34a with a large piston diameter 34 is, and the sum L1 + L2 of the lengths of the sections 34a with a large diameter. If, on the other hand, the piston 34with reference to the cylinder 32b If it is tilted, the opposite ends of the section will appear. 34a with a large diameter and an inner wall of the cylinder 32b in contact. A large tilt causes the piston to seize in the cylinder, preventing any smooth movement of the cylinder. The degree of tilt increases with an increase in the distance L between the opposite ends of the sections. 34a with a large diameter. The desired throttling characteristic and the stability of the piston's operation. 34 This can be achieved by setting the value for L3 such that L = L1 + L2 + L3, which is determined by the lengths L1 + L2 of the sections. 34a with a large diameter, on which the appropriate throttling characteristic can be achieved, and the acceptable value of the piston's tilt. 34 is certain.

[0039] The diameter of the end 34cthe membrane 33 , the one with the membrane 33 The contact area is 50% or less of the diameter D2 of the sections. 34a Set with a large diameter. A small cross-sectional area at the end. 34c contributes to an increase in the surface pressure of a contact section between the piston 34 and the membrane 33 (the section where the piston 34 and the membrane 33 (are in contact with each other) which hinders the formation of an oil film in the contact area. The presence of an oil film causes a reduction in the friction of the piston. 34 on the membrane 33 transmitted force, which impairs the damping effect. Therefore, it is effective to increase the diameter of the end. 34c to reduce it in order to prevent the damping effect from deteriorating.

[0040] In the previously described embodiment, the fluid is routed through the channel 31d to the fluid supply chamber 31a supplied. As in Fig. As shown in section 5, channels can 330a in sections of the membrane 33 be trained, which is not an outstanding section 310b are facing each other, so that the fluid from the fluid storage chamber 320a via the channels 330a to a fluid supply chamber 310a is supplied. As in Fig. As shown in 6, the channels can 330a They can be arranged at equal intervals around a circumference. This allows for a simplified setup on a single channel in a variable-throttle configuration. 310 can be dispensed with.

[0041] In the previously described embodiment, the piston 34 through the coil spring 35 pressed. However, another elastic element, such as a rubber band or an air spring, can be used.

[0042] Reference sign 310 , 310a , 310b , 320 , 320a , 320d and 330 in Fig. 5 and Fig. 6 correspond to the reference symbols 31 , 31a , 31b , 32 , 32a , 32d and 33 in Fig. 3.

[0043] A variably throttled hydrostatic bearing has a diaphragm. 33 , which is an outstanding section 31b is faced across a predetermined gap, and has a delivery port 31c , which is in the outstanding section 31b is designed to be equipped with a hydrostatic bag 2a is connected, and it represents a throttling amount based on the dimension of a gap between the membrane. 33 and the outstanding section 31b one. The variably throttled hydrostatic bearing also has a piston. 34, which has a surface on the side of the membrane at its first end 33 , which is opposite a surface that is opposite the projecting section 31b is facing, comes into contact, a cylinder 32b , which the piston 34 so that the piston 34 is movable, and which, together with the piston 34 a fluid chamber 32c forms, and a coil spring 35 , which are in the fluid chamber 32c is recorded to form a second end of the piston 34 to press. QUOTES INCLUDED IN THE DESCRIPTION

[0044] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0045] JP 10-196655 A [0002, 0003]

Claims

[1] Variable throttle hydrostatic bearing with: a hydrostatic pocket formed in a storage area; a fluid supply device that supplies a fluid to the hydrostatic pocket; a fluid channel that forms a channel for a fluid extending from the fluid supply device to the hydrostatic pocket; a variable throttle, which is provided in the middle of the fluid channel and throttles the flow rate of the fluid, so that the fluid is introduced into the hydrostatic pocket, the variable throttle has the following features: a fluid storage chamber; a fluid supply chamber with a protruding section in its central section; a membrane that separates the fluid supply chamber from the fluid storage chamber and in which a surface of the membrane is perpendicular to a direction of the thickness of the membrane facing the projecting section via a predetermined gap, and a channel that is provided in the projecting section and is connected to the hydrostatic pocket, wherein the variable throttle sets a throttling amount using an opening degree of the gap between the diaphragm and the projecting section, a piston which at its first end comes into contact with a surface on the side of the membrane that is opposite to the surface facing the projecting section; a cylinder that accommodates the piston in such a way that the piston is movable, and which together with the piston forms a fluid chamber; and an elastic element that pushes a second end of the piston and is contained within the cylinder. [2] Variable throttle hydrostatic bearing according to claim 1, wherein the cylinder is closed at its first end and a fluid in the fluid chamber flows into and out of the cylinder via a gap between the piston and an inner circumferential surface of the cylinder. [3] Variable throttle hydrostatic bearing according to claim 1 or 2, wherein the piston has large diameter sections at axially opposite ends of a small diameter section. [4] Variable throttle hydrostatic bearing according to any one of claims 1 to 3, wherein the first end of the piston has a smaller cross-sectional area than the large diameter sections of the piston. [5] Variable throttle hydrostatic bearing according to any one of claims 1 to 4, wherein a section of the diaphragm which is not facing the projecting section has a channel connecting the fluid supply chamber and the fluid storage chamber.