Testing device for ball screw devices

Abstract

The test apparatus for a ball screw device comprises a support section that rotatably supports the rotating component of the ball screw device and linearly supports the other linear component, a first motor that generates torque, and a load device that applies a load to the linear component. The load device comprises a movable component positioned in a first direction relative to the linear component and movable in the axial and orthogonal directions, a reaction force generating mechanism positioned in a first direction relative to the movable component and pressing the movable component from the first direction, and a radial load mechanism that moves the movable component in an orthogonal direction. The movable component is relatively movable in an orthogonal direction relative to the reaction force generating mechanism. The movable component has a connecting section capable of transmitting loads to the linear component in a second direction and an orthogonal direction.

Description

Technical Field

[0001] The present disclosure relates to a test apparatus for a ball screw device.

Background Art

[0002] A ball screw device is a device that converts rotational motion into linear motion or converts linear motion into rotational motion. Conventionally, a test apparatus for a ball screw device has been used to confirm the operation of this ball screw device and evaluate its efficiency. Further, as an example of a test apparatus for a ball screw device, those of the following patent documents can be cited. Hereinafter, the test apparatus for a ball screw device may sometimes be simply referred to as a test apparatus.

[0003] The test apparatus of the following patent document includes an axial load mechanism that generates an axial load (hereinafter referred to as an axial load) and a radial load mechanism that generates a radial load (hereinafter referred to as a radial load). The axial load mechanism is disposed between two nuts of the axial load mechanism. The radial load mechanism includes a block disposed outside the axial load mechanism in the radial direction, a rail, a slider movable along the rail, and a spacer interposed between the block and the slider. Further, by replacing the spacers with different thicknesses, the magnitude of the radial load is changed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, ball screw devices are mounted on electric brake systems that press brake pads. When an electric brake system presses the brake pads, it receives an axial load opposite to the direction of pressure on the brake pads and a load in the direction of rotation of the brake pads. The load in the direction of rotation of the brake pads is converted into a radial load and transmitted to the ball screw device. Furthermore, the radial load transmitted to the ball screw device fluctuates depending on the load applied to the brake pads and the rotation speed of the tires. Thus, the radial load acting on the ball screw device is not constant.

[0006] On the other hand, with the above-mentioned test apparatus, the spacer cannot be changed during the test, and the magnitude of the radial load remains constant during the test. Therefore, it is not possible to conduct tests that simulate environments in which the magnitude of the radial load changes.

[0007] This disclosure is made in view of the above and aims to provide a test apparatus for a ball screw device that can change the magnitude of the radial load during testing. [Means for solving the problem]

[0008] To achieve the above objective, a test apparatus for a ball screw device according to one aspect of the present disclosure comprises: a support portion that rotatably supports one of the rotating parts of the ball screw device, the screw shaft and the nut, and linearly supports the other linear part; a first motor that generates torque to rotate the rotating part; and a load device that applies a load to the linear part, wherein the direction parallel to the central axis of the screw shaft is defined as the axial direction, one of the axial directions is defined as the first direction, the other of the axial directions is defined as the second direction, and the direction perpendicular to the axial direction is defined as the orthogonal direction; the load device comprises: a movable part arranged in the first direction relative to the linear part and movable in the axial direction and the orthogonal direction; a reaction force generating mechanism arranged in the first direction relative to the movable part and pressing the movable part from the first direction; and a radial load mechanism that moves the movable part in the orthogonal direction. The movable part is movable relative to the reaction force generating mechanism in the orthogonal direction. The movable part has a connecting portion capable of transmitting loads to the linear part in the second direction and the orthogonal direction.

[0009] In the ball screw device testing apparatus of this disclosure, when the linear component moves in a first direction, the moving component is pressed and moves in the first direction. At the same time, the moving component receives a reaction force (load in a second direction) from the reaction force generating mechanism corresponding to the amount of movement in the first direction. Therefore, an axial load is applied to the linear component. The moving component is also movable relative to the reaction force generating mechanism in a direction perpendicular to it. When the radial load mechanism moves the moving component in a direction perpendicular to it, a load in a direction perpendicular to it (radial load) is applied to the linear component. As the amount of movement in the direction perpendicular to it by the moving component increases, the radial load increases. Thus, according to this disclosure, the magnitude of the radial load can be changed during testing.

[0010] Furthermore, in the ball screw device testing apparatus described above, the connecting portion may be formed from the same material as the moving component and may be formed integrally with the moving component. Alternatively, the connecting portion may be a separate component from the moving component. Alternatively, the connecting portion may be able to be fitted onto the linear motion component.

[0011] Furthermore, in the ball screw device testing apparatus described above, the loading device comprises a housing having a through hole that penetrates in the axial direction, into which the movable component is inserted, and which supports the movable component so as to be movable in the axial direction, and a guide mechanism that supports the housing so as to be movable in the orthogonal direction. The radial loading mechanism abuts against or connects to the housing from the orthogonal direction.

[0012] According to the above configuration, when the radial loading mechanism moves the housing in an orthogonal direction, the moving parts supported by the housing also move in an orthogonal direction, and a radial load is applied to the linear moving parts.

[0013] Furthermore, in the ball screw device testing apparatus described above, at least two guide mechanisms are provided. At least two of the guide mechanisms are arranged apart from each other in the axial direction.

[0014] The reaction force generation mechanism is a mechanism for applying a load in a second direction (axial load) to a linear motion component. However, when the moving component is moved in a perpendicular direction by the radial load mechanism, the moving component may tilt with the linear motion component as the pivot point. When the moving component tilts, the load in the second direction acting on the linear motion component from the reaction force generation mechanism also tilts, resulting in a radial load. In this way, the reaction force generation mechanism can apply a radial load to the linear motion component, potentially causing the magnitude of the radial load to deviate from a predetermined value. On the other hand, with the above configuration, the moving component is supported by two or more guide mechanisms arranged axially apart, making it less likely to tilt. Therefore, the radial load acting on the linear motion component is limited to the radial load generated by the radial load mechanism, and the magnitude of the radial load can be kept within a predetermined value.

[0015] Furthermore, in the ball screw device testing apparatus described above, the moving part has a contact surface facing the first direction. The reaction force generating mechanism has an opposing surface facing the second direction and in contact with the contact surface. One of the contact surface and the opposing surface is provided with a plurality of rolling elements to reduce friction between the contact surface and the other opposing surface.

[0016] Due to the reaction force from the reaction force generation mechanism, a large axial load acts between the contact surface and the opposing surface. This increases the frictional force between the contact surface and the opposing surface, which may hinder the smooth movement of the moving part in the orthogonal direction. On the other hand, with the above configuration, the frictional force between the contact surface and the opposing surface is reduced. Therefore, the movement of the moving part in the orthogonal direction becomes smoother. Furthermore, when the frictional force between the contact surface and the opposing surface is reduced, it becomes difficult to transmit the load in the second width direction (radial load) from the moving part to the reaction force generation mechanism. Therefore, the radial load acting on the linear motion part falling below a predetermined value is avoided.

[0017] Furthermore, in the ball screw device testing apparatus described above, one of the orthogonal directions is designated as the first orthogonal direction. The other of the orthogonal directions is designated as the second orthogonal direction. The apparatus includes a biasing support portion arranged in the second orthogonal direction with respect to the movable part and movable in the orthogonal direction, a biasing portion arranged between the movable part and the biasing support portion and exerting a biasing force in the orthogonal direction, and a moving device for moving the biasing support portion in the orthogonal direction. When the biasing support portion moves in the first orthogonal direction and the length of the biasing portion in the orthogonal direction becomes smaller than its natural length, the biasing portion exerts a biasing force that biases the movable part in the first orthogonal direction.

[0018] If the moving device directly presses the moving part in the first orthogonal direction, the radial load acting on the moving part will increase, potentially leading to damage to the moving part. On the other hand, with the above configuration, the moving part is pressed in the first orthogonal direction by the biasing force of the biasing part, thus reducing the radial load acting on the moving part. Therefore, damage to the moving part is avoided.

[0019] Furthermore, in the ball screw device testing apparatus described above, the moving device comprises a radial motor and a radial ball screw device that operates using the torque generated by the radial motor to move the biasing support in the orthogonal direction.

[0020] According to the above configuration, when the radial motor is driven, the radial ball screw device converts the rotational motion into a linear motion and moves the support portion for the biasing portion. As a result, the length of the biasing portion changes, and the magnitude of the biasing force is also changed.

Advantages of the Invention

[0021] According to the test device for a ball screw device of the present disclosure, the magnitude of the radial load can be changed during the test.

Brief Description of the Drawings

[0022] [Figure 1] FIG. 1 is a schematic view of the test device for a ball screw device according to Embodiment 1 as viewed from above. [Figure 2] FIG. 2 is a schematic view of the reaction force generating mechanism, the moving parts, the support part, and the operating device according to Embodiment 1 as viewed from the first width direction, and more specifically, it is a schematic view as viewed from the direction indicated by arrow II in FIG. 1. [Figure 3] FIG. 3 is a schematic view of the moving parts and its vicinity according to Embodiment 1 as viewed from above. [Figure 4] FIG. 4 is a schematic view of the radial load mechanism and the moving parts according to Embodiment 1 as viewed from the second direction, and more specifically, it is a schematic view as viewed from the direction indicated by arrow IV in FIG. 1. [Figure 5] FIG. 5 is a schematic view of the reaction force generating mechanism, the moving parts, the support part, and the operating device during the test in Embodiment 1 as viewed from the first width direction. [Figure 6] FIG. 6 is a schematic view of the radial load mechanism and the moving parts during the test in Embodiment 1 as viewed from the second direction. [Figure 7] FIG. 7 is a schematic view of the reaction force generating mechanism, the moving parts, the support part, and the operating device in the test device for a ball screw device according to Embodiment 2 as viewed from the first width direction. [Figure 8] FIG. 8 is a schematic view of the test device for a ball screw device according to Embodiment 3, with the jig device and its vicinity enlarged and viewed from the horizontal direction.

Modes for Carrying Out the Invention

[0023] The forms for implementing this disclosure will be described in detail with reference to the drawings. This disclosure is not limited by the contents described below. Furthermore, the components described below include those that are readily conceivable to a person skilled in the art, and those that are substantially the same. In addition, the components described below can be combined as appropriate.

[0024] (Embodiment 1) Figure 1 is a schematic diagram of the test apparatus for the ball screw device of Embodiment 1, viewed from above. Before describing the test apparatus 100 for the ball screw device of Embodiment 1, the ball screw device 110 will be briefly described. As shown in Figure 1, the ball screw device 110 comprises a screw shaft 111, a nut 112 into which the screw shaft 111 is inserted, and a plurality of balls (not shown) arranged between the screw shaft 111 and the nut 112. Hereinafter, the direction parallel to the central axis O of the screw shaft 111 will be referred to as the axial direction.

[0025] In the ball screw device 110, torque is transmitted to one of the components, the screw shaft 111 and the nut 112, causing that component (which may be referred to as the rotating component) to rotate. The other component of the screw shaft 111 and the nut 112 (which may be referred to as the linear motion component) then moves linearly in the axial direction (which may be referred to as linear motion). In the ball screw device test apparatus 100 of Embodiment 1, the screw shaft 111 corresponds to the rotating component, and the nut 112 corresponds to the linear motion component.

[0026] Next, the test apparatus 100 for ball screw devices will be described. In the following description, the test apparatus 100 for ball screw devices will be described using the ball screw device 110 to be tested already installed as an example.

[0027] As shown in Figure 1, the ball screw device test apparatus 100 of Embodiment 1 comprises a base 101, a support part 1 for supporting the ball screw device 110 to be tested, an actuator 2 for operating the ball screw device 110, and a load device 3 for applying a load to the ball screw device 110. The load device 3 also comprises a movable part 50, a reaction force generating mechanism 10, and a radial load mechanism 60.

[0028] Figure 2 is a schematic diagram of the reaction force generating mechanism, movable parts, support part, and operating device of Embodiment 1, viewed from the first width direction, and more specifically, a schematic diagram viewed from the direction indicated by arrow II in Figure 1. As shown in Figure 2, the base 101 of this embodiment extends in the horizontal direction. The installation surface 102 of the base 101 faces upward Y1 in the vertical direction. Therefore, in the following description, the direction that the installation surface 102 of the base 101 faces will be referred to as upward Y1, and the direction opposite to the direction that the installation surface 102 faces will be referred to as downward Y2.

[0029] In this embodiment, the base 101 is horizontal, but the present disclosure also allows the base 101 to be inclined with respect to the horizontal direction, or the normal to the base 101 to extend in the horizontal direction, and there are no particular restrictions on the orientation of the base 101.

[0030] The support part 1 rotatably supports the screw shaft 111 and supports the nut 112 so that it can move in the axial direction. The support part 1 also supports the ball screw device 110 so that the central axis O of the screw shaft 111 is horizontal.

[0031] A movable component 50 is positioned on one side of the axial direction when viewed from the support part 1 (screw shaft 111), and an actuator 2 is positioned on the other side of the axial direction. Hereinafter, the direction in which the movable component 50 is positioned when viewed from the support part 1 will be referred to as the first direction X1, and the direction in which the actuator 2 is positioned when viewed from the support part 1 will be referred to as the second direction X2. Furthermore, the horizontal direction perpendicular to the axial direction will be referred to as the width direction.

[0032] As shown in Figure 1, the radial loading mechanism 60 is positioned on one side in the width direction relative to the movable component 50. Hereinafter, the direction in which the radial loading mechanism 60 is positioned, as viewed from the movable component 50, will be referred to as the first width direction Z1, and the direction opposite to the first width direction Z1 will be referred to as the second width direction Z2. In this embodiment, the width direction is perpendicular to the axial direction, and may therefore be referred to as the orthogonal direction.

[0033] As shown in Figure 2, the actuator 2 comprises a first motor 20 and a torque sensor 23 arranged in order from the second direction X2. The first motor 20 generates torque to operate the ball screw device 110. The first motor 20 has a main body 21 and an output shaft 22.

[0034] The torque sensor 23 is positioned between the support unit 1 (ball screw device 110) and the first motor 20, and measures the torque transmitted to the ball screw device 110. The torque sensor 23 has a main body 24, a first shaft 25 extending from the main body 24 in a second direction X2, and a second shaft 26 extending from the main body 24 in a first direction X1.

[0035] The output shaft 22 and the first shaft 25 are connected by a coupling 90. The second shaft 26 and the screw shaft 111 are connected by a coupling 91.

[0036] As described above, when the first motor 20 is driven, torque is transmitted to the screw shaft 111 via the torque sensor 23. Then the screw shaft 111 rotates, and the nut 112 moves in the axial direction.

[0037] The reaction force generating mechanism 10 is positioned in a first direction X1 relative to the movable part 50. Furthermore, when the movable part 50 moves in the first direction X1, the reaction force generating mechanism 10 presses the movable part 50 in a second direction X2, thereby applying a reaction force to the movable part 50. This reaction force generating mechanism 10 allows an axial load to be applied to the nut 112 that moves in the first direction X1 during testing of the ball screw device 110. The reaction force generating mechanism 10 of this embodiment includes an axial motor 30 arranged in order from the first direction X1, a load-side first ball screw device 33, a first support part 37 for the biasing part, a first biasing part 45, a load cell 47, and a pressing part 48.

[0038] The axial motor 30 generates power to adjust the axial length of the first biasing unit 45. The axial motor 30 comprises a main body 31 and an output shaft 32.

[0039] The load-side first ball screw device 33 converts the rotational motion generated by the axial motor 30 into linear motion. The load-side first ball screw device 33 comprises a screw shaft 34, a nut 35, and a number of balls (not shown). The base 101 is also provided with a load-side first support portion 36 that supports the load-side first ball screw device 33. The load-side first support portion 36 rotatably supports the screw shaft 34 and axially movable supports the nut 35. The screw shaft 34 is connected to the output shaft 32 of the axial motor 30 by a coupling 92.

[0040] The first support portion 37 for the biasing portion comprises a main body portion 38 and a rod 39 supported by the main body portion 38 so as to be movable in the axial direction. The rod 39 extends from the main body portion 38 in a second direction X2. A flange 40 is provided at the end of the rod 39 in the second direction X2.

[0041] The first biasing part 45 is a component that exerts a biasing force. The first biasing part 45 is positioned between the end face of the main body 38 in the second direction X2 and the flange 40, and biases the flange 40 in the second direction X2. Specific examples of the first biasing part 45 include coil springs and disc springs. In the case of disc springs, multiple disc springs may be arranged in the axial direction.

[0042] In this embodiment, the main body 38 is supported so as to be movable in the axial direction by a linear guide 41 fixed to the base 101. The linear guide 41 has a rail 42 that extends in the axial direction and a slider 43 that is movable in the axial direction along the rail 42. A nut 35 of the load-side first ball screw device 33 is connected to the end of the main body 38 in the first direction X1. In this disclosure, the nut 35 may rotate and the screw shaft 34 may move in the axial direction.

[0043] The load cell 47 measures the axial load. The load cell 47 is fixed to the flange 40 of the first support portion 37 for the biasing portion in the second direction X2.

[0044] The pressing portion 48 is attached to the load cell 47 from a second direction X2. The surface of the pressing portion 48 facing the second direction X2 is the opposing surface 49. The opposing surface 49 is a plane that extends in the vertical and width directions. The opposing surface 49 is in contact with the moving part 50 from a first direction X1.

[0045] Figure 3 is a schematic diagram of the movable component of Embodiment 1 and its vicinity, viewed from above. As shown in Figure 3, the movable component 50 is a shaft-shaped component that extends in the axial direction. The movable component 50 is supported by a housing 51. The housing 51 is a cylindrical component with a through hole 52 that penetrates in the axial direction. The movable component 50 is inserted into the through hole 52. The movable component 50 is also supported by the housing 51 so as to be movable in the axial direction.

[0046] The housing 51 is supported by a linear guide (guide mechanism) 53 installed on the base 101. The linear guide 53 has a rail 54 extending in the width direction and a slider 55 (see Figures 2 and 4) that is movable axially along the rail 54. Thus, the housing 51 is supported on the base 101 so as to be movable in the width direction. In other words, the movable part 50 can move in the width direction together with the housing 51.

[0047] In this embodiment, two linear guides 53 are provided. The two linear guides 53 are positioned axially apart from each other. This prevents the housing 51 (movable part 50) from tilting. Although this embodiment has two linear guides 53, this disclosure may also have three or more. This would more reliably prevent the housing 51 (movable part 50) from tilting. In addition, this disclosure may also have only one linear guide 53.

[0048] The movable part 50 has a greater axial length than the housing 51. Therefore, both ends of the movable part 50 protrude axially from the housing 51. The end face of the movable part 50 in the first direction X1 is a contact surface 56. The contact surface 56 is a plane that extends in the vertical and width directions. The contact surface 56 is in contact with the opposing surface 49 of the pressing part 48. In other words, the movable part 50 is not connected to the pressing part 48. Therefore, the movable part 50 is movable relative to the pressing part 48 (reaction force generating mechanism 10) in the width direction (orthogonal direction).

[0049] The width of the opposing surface 49 is greater than the width of the contact surface 56. Therefore, even when the moving part 50 moves in the width direction, the contact surface 56 comes into contact with the opposing surface 49.

[0050] Furthermore, the movable part 50 has a connecting part 11 to transmit loads in the second direction X2 and the width direction (orthogonal direction) to the rotating part, the nut 112. In this embodiment, the connecting part 11 is a separate part from the movable part 50 and can be separated from the movable part 50.

[0051] The connecting portion 11 connects the movable part 50 and the nut 112 (rotating part). The connecting portion 11 in this embodiment includes a connecting portion body 12, a first fitting portion 13 protruding from the connecting portion body 12 in a first direction X1, and a second fitting portion 14 protruding from the connecting portion body 12 in a second direction X2.

[0052] A recess 58 is formed on the second end face 57 of the movable part 50 in the second direction X2, recessed in the first direction. The first fitting part 13 is fitted into the recess 58 of the movable part 50. The second fitting part 14 is fitted to the inner circumference of the nut 112. Thus, the connecting part 11 is detachably attached to both the movable part 50 and the nut 112. Furthermore, when the connecting part 11 (movable part 50) moves in the width direction, the outer circumferential surface of the second fitting part 14 presses against the inner circumferential surface of the nut 112 in the width direction. Therefore, the connecting part 11 can transmit a load in the width direction to the nut 112. In addition, the end face of the connecting part body 12 facing the second direction X2 abuts against the end face of the nut 112. Therefore, the connecting part 11 can transmit a load in the second direction X2 to the nut 112.

[0053] The first fitting portion 13 may be fitted into the recess 58 with a gap fit or fitted tightly. Similarly, the second fitting portion 14 may be fitted into the nut 112 with a gap fit or fitted tightly. During the test, the connecting portion 11 receives a load from the nut 112 in the first direction X1. The connecting portion 11 also receives a load (load in the second direction X2) from the reaction force generating mechanism 10. Therefore, even if the first fitting portion 13 is fitted into the recess 58 with a gap fit, or the second fitting portion 14 is fitted into the nut 112 with a gap fit, the connecting portion 11 will not detach from the movable part 50 and the nut 112.

[0054] As shown in Figure 3, the support portion 1 of this embodiment has a bearing 4 that rotatably supports the screw shaft 111. The support portion 1 also has a cylindrical portion 5 located radially outward from the nut 112. A groove (not shown) extending in the axial direction is formed in this cylindrical portion 5. An anti-rotation mechanism (not shown) that fits into the groove is provided on the outer circumferential surface of the nut 112. Therefore, the nut 112 is supported by the support portion 1 in a way that prevents rotation and allows movement in the axial direction.

[0055] Figure 4 is a schematic diagram of the radial load mechanism and movable part of Embodiment 1 viewed from a second direction, and more specifically, a schematic diagram viewed from the direction indicated by arrow IV in Figure 1. The radial load mechanism 60 is a mechanism for moving the movable part 50 in the width direction. This radial load mechanism 60 allows a radial load to be applied to the nut 112. As shown in Figure 4, the radial load mechanism 60 includes a radial motor 61 arranged in order from the first width direction Z1, a load-side second ball screw device 64, a second support part 68 for the biasing part, and a second biasing part 75.

[0056] The radial motor 61 generates power to adjust the length of the second biasing unit 75. The radial motor 61 comprises a main body 62 and an output shaft 63.

[0057] The load-side second ball screw device 64 converts the rotational motion generated by the radial motor 61 into linear motion. The load-side second ball screw device 64 comprises a screw shaft 65, a nut 66, and a plurality of balls (not shown). The base 101 is provided with a load-side second support portion 67 that supports the load-side second ball screw device 64. The load-side second support portion 67 rotatably supports the screw shaft 65 and supports the nut 66 so that it can move in the axial direction. The screw shaft 65 is connected to the output shaft 63 of the radial motor 61 by a coupling 93. In this disclosure, the nut 66 may rotate and the screw shaft 65 may move in the axial direction.

[0058] The second support portion 68 for the biasing portion comprises a main body portion 69 and a rod 70 supported by the main body portion 69 so as to be movable in the width direction. The rod 70 extends from the main body portion 69 in the second width direction Z2.

[0059] A flange 71 is provided at the end of the rod 70 in the second width direction Z2. The flange 71 abuts against the side surface 59 of the housing 51 in the first width direction Z1. The flange 71 is also connected to the side surface 59. In other words, the flange 71 is connected to the side surface 59 of the housing 51 in the first width direction Z1. The rod 70 (flange 71) and the housing 51 are integrated.

[0060] The second biasing part 75 is a component that exerts a biasing force. The second biasing part 75 is positioned between the end face of the main body 69 in the second width direction Z2 and the flange 71, and biases the flange 71 in the second width direction Z2. Specific examples of the second biasing part 75 include coil springs and disc springs. In the case of disc springs, multiple disc springs may be arranged in the axial direction.

[0061] In this embodiment, the main body 69 is supported so as to be movable in the axial direction by a linear guide 72 fixed to the base 101. The linear guide 72 has a rail 73 that extends in the axial direction and a slider 74 that is movable in the axial direction along the rail 73. A nut 66 of the load-side second ball screw device 64 is connected to the end of the main body 69 in the first width direction Z1.

[0062] Next, we will explain how to use the ball screw device testing apparatus 100.

[0063] Figure 5 is a schematic diagram of the reaction force generating mechanism, movable part, support part, and operating device in Embodiment 1, viewed from the first width direction during testing. In this description, the state before the start of the test is as shown in Figure 5, with the movable part 50 (connecting part 11) and the linear motion part (nut 112) already in contact. Also, the axial length of the first biasing part 45 is its natural length, and the first biasing part 45 is not exerting a biasing force (see arrow F1 in Figure 5). Therefore, there is no axial load on the nut 112 (see arrow F3 in Figure 5).

[0064] Furthermore, in the radial loading mechanism 60 in its pre-test state, the length of the second biasing part 75 is its natural length, and the second biasing part 75 is not exerting any biasing force. In other words, the radial loading mechanism 60 is not pressing the movable part 50 in the second width direction Z2. Therefore, no radial load is applied to the nut 112.

[0065] As shown in Figure 5, in the test, the first motor 20 is driven to move the nut 112 in the first direction X1 (see arrow A1 in Figure 5). When the nut 112 moves, the moving part 50 is pressed and moves in the first direction X1 (see arrow A2 in Figure 5). Also, the pressing part 48 is pressed in the first direction X1 by the moving part 50, and the flange 40 moves in the first direction X1 (see arrow A3 in Figure 5).

[0066] As a result, the axial length of the first biasing part 45 is reduced. In other words, the first biasing part 45 exerts a biasing force (see arrow F1 in Figure 5) that biases the flange 40 in the second direction X2. This causes the pressing part 48 to press the moving part 50 in the second direction X2 (see arrow F2 in Figure 5). The moving part 50 then presses the nut 112 in the second direction X2. Therefore, the nut 112 moves in the first direction X1 while receiving an axial load (see arrow F3 in Figure 5).

[0067] Furthermore, as the amount of movement of the nut 112 in the first direction X1 increases, the axial length of the first biasing part 45 decreases further. In other words, the biasing force of the first biasing part 45 that biases the flange 40 in the second direction X2 (see arrow F1 in Figure 5) increases. Consequently, the load that the pressing part 48 applies to the moving part 50 in the second direction X2 (see arrow F2 in Figure 5) also increases, and the axial load acting on the nut 112 (see arrow F3 in Figure 5) increases. From the above, as the amount of movement of the nut 112 in the first direction X1 increases, the axial load acting from the reaction force generating mechanism 10 (see arrow F3 in Figure 5) increases.

[0068] Furthermore, during the test, the torque sensor 23 measures the torque transmitted to the screw shaft 111 of the ball screw device 110. The load cell 47 measures the axial load acting on the moving part 50. The efficiency of the ball screw device 110 is then calculated from the data measured by the torque sensor 23 and the load cell 47. This allows for the evaluation of the characteristics of the ball screw device 110.

[0069] Furthermore, when the axial motor 30 is driven during the test, the main body 38 of the first support part 37 for the biasing part moves in the axial direction. If the main body 38 moves in the second direction X2 (see arrow A4 in Figure 5), the axial length of the first biasing part 45 decreases, and the biasing force of the first biasing part 45 increases. On the other hand, if the main body 38 moves in the first direction X1 (see arrow A5 in Figure 5), the axial length of the first biasing part 45 increases, and the biasing force of the first biasing part 45 decreases. From the above, it can be seen that, according to this embodiment, the magnitude of the reaction force generated by the reaction force generating mechanism 10 can be changed during the test. In other words, the magnitude of the axial load acting on the nut 112 (see arrow F3 in Figure 5) can be changed.

[0070] Figure 6 is a schematic diagram of the radial load mechanism and moving parts during testing in Embodiment 1, viewed from a second direction. As shown in Figure 6, when a radial load is applied to the nut 112, the radial motor 61 of the radial load mechanism 60 is driven, moving the main body 69 of the second support part 68 for the biasing part in the second width direction Z2 (see arrow B1 in Figure 6). This reduces the length of the second biasing part 75. In other words, the second biasing part 75 biases the flange 71 toward the second width direction Z2 (see arrow F4 in Figure 6). As a result, the housing 51 and the moving parts 50 move toward the second width direction Z2 (see arrow B2 in Figure 6).

[0071] Here, the movable part 50 is movable relative to the pressing part 48 (reaction force generating mechanism 10) in the width direction (orthogonal direction). Therefore, as shown in Figure 3, the contact surface 56 of the movable part 50 slides against the opposing surface 49 of the pressing part 48 (see arrow B3 in Figure 3). On the other hand, the second fitting part 14 of the connecting part 11 catches on the inner circumferential surface of the nut 112, pressing the nut 112 in the second width direction Z2. As a result, a radial load (see arrow F5 in Figure 3) is applied to the nut 112.

[0072] Furthermore, as the amount of movement of the main body 69 in the second width direction Z2 increases, the amount of movement of the movable part 50 in the second width direction Z2 (see arrow F4 in Figure 6) increases, and the radial load on the nut 112 (see arrow F5 in Figure 3) increases.

[0073] From the above, the ball screw device test apparatus 100 of Embodiment 1 can apply or not apply a radial load to the nut 112. Furthermore, the magnitude of the radial load can be changed. Moreover, the radial load mechanism 60 that generates the radial load is a mechanism independent of the reaction force generating mechanism 10 that generates the axial load (see arrow F3 in Figure 3). Therefore, the magnitude of the radial load can be set regardless of the magnitude of the axial load.

[0074] Although Embodiment 1 has been described above, this disclosure is not limited to the above example. For example, a reduction gear may be further provided to increase the torque of the first motor 20, the axial motor 30, and the radial motor 61. Also, if the test is not for testing efficiency but for confirming operation such as whether abnormal noise occurs, or for evaluating durability, the ball screw device test apparatus 100 does not need to be equipped with a torque sensor 23 or a load cell 47. Furthermore, a temperature sensor or the like may be added to the ball screw device test apparatus 100 to measure the temperature of the ball screw device 110 during testing. In addition, although the actuator 2 is arranged in the second direction X2 with respect to the support part 1, it may be arranged in the width direction Z and the torque may be transmitted to the screw shaft 111 by a pulley or the like. In this way, the configuration of the ball screw device test apparatus 100 may be changed as needed. Furthermore, although the reaction force generating mechanism 10 in Embodiment 1 has a pressing part 48, this disclosure does not require the pressing part 48 to be included.

[0075] Furthermore, the reaction force generating mechanism 10 of Embodiment 1 includes an axial motor 30 and a load-side first ball screw device 33 as a moving device for moving the main body 38 of the biasing part first support part 37 in the axial direction. However, in this disclosure, a hydraulic actuator or an air actuator may be used instead of the axial motor 30 and the load-side first ball screw device 33.

[0076] Similarly, in this embodiment, the radial load mechanism 60 is equipped with a radial motor 61 and a load-side second ball screw device 64 as a moving device for moving the main body 69 in the width direction. However, in this disclosure, a hydraulic actuator or an air actuator may be used instead of the radial motor 61 and the load-side second ball screw device 64.

[0077] Furthermore, in this embodiment, the movable component 50 is pressed in the second width direction Z2 by the biasing force of the second biasing unit 75. However, it is also possible to move the movable component in the width direction by a moving device (such as a radial motor 61 and a load-side second ball screw device 64, or a hydraulic actuator or an air actuator) without using the second biasing unit 75. However, if the movable component 50 is moved directly by the moving device, the load acting on the movable component 50 will be large, which may lead to damage to the movable component 50, etc. Therefore, by using the second biasing unit 75 as in this embodiment, the load acting on the movable component 50 can be reduced, and damage to the movable component 50, etc. can be avoided.

[0078] Furthermore, in the embodiment, the description of how to use the ball screw device testing apparatus 100 gave an example where the axial length of the first biasing part 45 is its natural length at the start of the test. However, in this disclosure, at the start of the test, the axial length of the first biasing part 45 may be less than its natural length, and an axial load (see arrow F3 in Figure 5) may be applied to the nut 112.

[0079] Furthermore, this disclosure states that, regarding the state before the start of the test, the movable part 50 (connecting part 11) and the linear motion part (nut 112) do not necessarily have to be in contact. In other words, the test may be started with an axial gap between the movable part 50 (connecting part 11) and the linear motion part (nut 112). In this case, after the test has started and the linear motion part (nut 112) has moved to a certain extent in the first direction X1, the linear motion part (nut 112) will come into contact with the movable part 50 (connecting part 11) and receive the load. Furthermore, regarding the axial gap, this disclosure states that the test may be started with an axial gap between the movable part 50 (connecting part 11) and the pressing part 48. Moreover, the test may be started with an axial gap between the movable part 50 (connecting part 11) and the pressing part 48, and also with an axial gap between the movable part 50 (connecting part 11) and the linear motion part (nut 112). In addition, the axial gap is not limited to the locations described above, but may be present at other connection points.

[0080] Furthermore, regarding the second fitting portion 14 of the connecting portion 11, although it is cylindrical in this embodiment, this disclosure may also be hemispherical in shape that can be inserted into the nut 112, and there are no particular limitations on the shape of the second fitting portion 14. Also, although the second fitting portion 14 in the embodiment is fitted to the inner circumference of the nut 112, this disclosure may also be configured so that the second fitting portion 14 is fitted to the outer circumference of the nut 112.

[0081] Furthermore, although the connecting portion 11 in the embodiment is connected to the linear motion component (nut 112) by fitting, this disclosure is not limited to this method of connection with the linear motion component. In other words, the connecting portion 11 does not have to have a second fitting portion 14. For example, the connecting portion and the linear motion component may be connected by fastening with fasteners such as bolts and nuts. Alternatively, the connecting portion may be designed to clamp the linear motion component from both sides in the width direction. In short, this disclosure is not particularly limited in shape as long as the connecting portion 11 can transmit loads in the second direction X2 and the width direction to the linear motion component.

[0082] Furthermore, with respect to the first fitting portion 13 of the connecting portion 11, this disclosure may also describe a first fitting portion 13 that fits onto the outer circumference of the movable part 50. Also, although the connecting portion 11 is connected to the movable part 50 by fitting, it may be connected by a method other than fitting. In addition, although the connecting portion 11 in this embodiment is a separate part from the movable part 50, this disclosure may also describe a connecting portion that is formed from the same material as the movable part 50 and is integrally formed with the movable part 50 (inseparable). Thus, there are no particular limitations on the shape of the connecting portion 11 in this disclosure.

[0083] Furthermore, in this embodiment, the opposing surface 49 of the pressing portion 48 and the contact surface 56 of the movable part 50 are simply in contact, but in this disclosure, rolling elements may be placed between the opposing surface 49 and the contact surface 56. Examples of rolling elements include balls, cylindrical rollers, and needles. This reduces the frictional force between the opposing surface 49 and the contact surface 56, allowing the movable part 50 to move smoothly in the width direction. Also, when the frictional force between the opposing surface 49 and the contact surface 56 is reduced, it becomes more difficult to transmit the load (radial load) in the second width direction Z2 from the movable part 50 to the pressing portion 48. Therefore, the radial load acting on the nut 112 being smaller than a predetermined value is avoided. In addition to interposing rolling elements, in order to reduce the frictional force, in this disclosure, lubricating oil may be applied to the opposing surface 49 or the contact surface 56.

[0084] Incidentally, as shown in Figure 3, the bearing 4 supporting the ball screw device 110 has gaps between the outer ring and the balls, and between the balls and the inner ring. Therefore, the entire ball screw device 110 may tilt due to radial loading during testing. The pivot point P (see Figure 3) when the ball screw device 110 tilts is the center of the bearing 4 of the support part 1. In addition, the ball screw device 110 has gaps between the nut 112 and the balls, and between the balls and the screw shaft 111, so the nut 112 may tilt relative to the screw shaft 111.

[0085] As described above, when the frictional force between the opposing surface 49 and the contact surface 56 is small due to the rolling elements and lubricant, if the entire ball screw device 110 or only the nut 112 tilts, the movable part 50 connected via the connecting part 11 may also tilt. The dashed line Q in Figure 3 indicates the position when the movable part 50 is tilted. When the movable part 50 tilts, the load in the second direction X2 generated by the reaction force generating mechanism 10 also tilts, resulting in the generation of a load in the second width direction Z2. As a result, a radial load other than the radial load generated by the radial load mechanism 60 is generated, and it may not be possible to set the magnitude of the radial load acting on the nut 112 to a predetermined value.

[0086] However, in this embodiment, the movable part 50 supports the housing 51 with two linear guides 53, making it difficult for the movable part 50 and the housing 51 to tilt. Therefore, the radial load acting on the nut 112 is limited to the radial load generated by the radial load mechanism 60, and the magnitude of the radial load acting on the nut 112 can be set to a predetermined value.

[0087] In addition, in the above-described embodiment, the reaction force generating mechanism 10 is configured such that the main body 38 of the first support portion 37 for the biasing portion moves in the axial direction. However, in this disclosure, the main body 38 may be fixed. Embodiment 2 in which the main body 38 is fixed will be described below.

[0088] (Embodiment 2) Figure 7 is a schematic diagram of the ball screw device test apparatus of Embodiment 2, showing the reaction force generating mechanism, moving parts, support part, and operating device viewed from the first width direction. As shown in Figure 7, the ball screw device test apparatus 100A of Embodiment 2 differs from Embodiment 1 in that the reaction force generating mechanism 10A does not include an axial motor 30, a load-side first ball screw device 33, and a linear guide 41. In other words, it differs from Embodiment 1 in that the main body of the support part for the biasing part is fixed to the base 101. According to Embodiment 2, it is not possible to intentionally increase or decrease the biasing force exerted by the first biasing part 45 during testing.

[0089] Embodiment 2 has been described above. In the embodiment described above, the screw shaft 111 is a rotating part and the nut 112 is a linear motion part, but in this disclosure, as will be described in Embodiment 3 below, the nut 112 may be a rotating part and the screw shaft 111 may be a linear motion part.

[0090] (Embodiment 3) Figure 8 is a schematic diagram of the ball screw device testing apparatus of Embodiment 3, showing an enlarged view of the jig and its vicinity from the horizontal direction. As shown in Figure 8, the support portion 1B of the ball screw device testing apparatus 100B of Embodiment 3 differs from Embodiment 1 in that it supports the screw shaft 111 so that it is immobile but movable in the axial direction, and the nut 112 is rotatably supported by the bearing 4B. In addition, a recess 113 is formed on the end face of the screw shaft 111 in the first direction X1, recessed in the second direction X2. The second fitting portion 14 of the connecting portion 11 is fitted into the recess 113. Even in this Embodiment 3, as with the other embodiments, the magnitude of the radial load acting on the screw shaft 111 can be changed during testing.

[0091] Although each embodiment has been described above, the ball screw device tested with the ball screw device test apparatus of this disclosure may be a ball screw device other than a ball screw device mounted on an electric brake device, and the type and size of the ball screw device are not particularly limited. Furthermore, in the description of the usage method of Embodiment 1, it was described that the pressing part 48 and the movable part 50 are in contact at the start of the test, but in this disclosure, the pressing part 48 and the movable part 50 are not in contact at the start of the test.

[0092] Furthermore, although the housing 51 in the embodiment supports the movable part 50 on the inner circumferential surface of the through hole 52, the present disclosure may also provide a ball spline on the inner circumferential surface of the housing 51 and support the movable part 50 via the ball spline. This allows for smooth axial movement by the movable part 50.

[0093] Furthermore, in this embodiment, the reaction force generating mechanism 10 (pressing part 48) and the movable part 50 are separable, but they may be connected. However, this disclosure requires that the movable part 50 be able to move relative to the reaction force generating mechanism 10 in the width direction (orthogonal direction). Therefore, when connecting the reaction force generating mechanism 10 (pressing part 48) and the movable part 50, it is necessary to connect them via a linear guide. This linear guide allows the movable part 50 to move in the width direction. Moreover, it also prevents the movable part 50 from tilting (see dashed line Q in Figure 3).

[0094] Furthermore, in this embodiment, the movable component 50 is supported so as to be movable in the axial direction by a cylindrical housing 51, but the movable component 50 may also be supported so as to be movable in the axial direction by a linear guide that extends in the axial direction, for example. Thus, there are no particular restrictions on the components that support the movable component 50 in this disclosure.

[0095] Furthermore, in the embodiment, a first support portion 37 for the biasing portion is provided to support the first biasing portion 45, but in this disclosure, only the first biasing portion 45 may be interposed between the nut 35 and the load cell 47. In this case, the first biasing portion 45 may be supported by methods such as fixing the end of the first biasing portion 45 in the first direction X1 to the end of the nut 35 in the second direction X2. This eliminates the need for the first support portion 37 for the biasing portion, thereby reducing the number of parts. Similarly, in the radial load mechanism 60, only the second biasing portion 75 may be interposed between the nut 66 and the housing 51, which eliminates the need for the second support portion 68 for the biasing portion, thereby reducing the number of parts.

[0096] Furthermore, regarding the guide mechanism that supports the housing 51 so as to be movable in the orthogonal direction, in this embodiment an example using a linear guide 53 was given, but the present invention may also be a linear guide device having a ball, such as a ball slider in which a ball is interposed between the rail 54 and the slider 55. Similarly, the present invention may use a linear guide device having a ball instead of the linear guides 41 and 72 that movably support the main body 38 and the main body 69.

[0097] Furthermore, this disclosure may supply air from the base 101 toward the housing 51 (movable part 50). Alternatively, magnets may be provided on the base 101 and the housing 51 (movable part 50) so that the base 101 and the housing 51 (movable part 50) repel each other due to magnetic force. In such an example, the gravitational force on the housing 51 (movable part 50) is reduced, and the radial load of the radial load mechanism 60 is more easily applied to the housing 51 (movable part 50).

[0098] Furthermore, this disclosure may also be a combination of the following configurations. (1) A support part that rotatably supports one of the rotating parts of a ball screw device, the screw shaft and the nut, and linearly supports the other linear part, A first motor that generates torque to rotate the aforementioned rotating part, A loading device that applies a load to the aforementioned linear motion component, Equipped with, The direction parallel to the central axis of the screw shaft is defined as the axial direction. One of the axial directions is designated as the first direction, The other direction in the axial direction is designated as the second direction. The direction perpendicular to the aforementioned axial direction is defined as the orthogonal direction. The aforementioned load device is A movable component is positioned in the first direction relative to the linear motion component and is movable in the axial direction and the orthogonal direction, A reaction force generating mechanism is positioned in the first direction relative to the moving part and presses the moving part from the first direction, A radial loading mechanism that moves the moving component in the orthogonal direction, Equipped with, The moving component is movable relative to the reaction force generating mechanism in the direction perpendicular to the said direction. The aforementioned moving component has a connecting portion capable of transmitting loads in the second direction and the orthogonal direction to the linear motion component, and is a test device for a ball screw device. (2) The connecting portion is formed from the same material as the movable part and is integrally formed with the movable part. (1) Test apparatus for ball screw devices as described above. (3) The connecting portion is a separate component from the movable part. (1) Test apparatus for ball screw devices as described above. (4) The connecting portion is designed to be fitted into the linear motion component. A test apparatus for a ball screw device as described in any one of (1) to (3). (5) The aforementioned load device is A housing having a through hole that penetrates in the axial direction, into which the movable component is inserted, and which supports the movable component so as to be movable in the axial direction, A guide mechanism that supports the housing so as to be movable in the orthogonal direction, Equipped with, The radial loading mechanism abuts against or connects to the housing from the orthogonal direction. A test apparatus for a ball screw device as described in any one of (1) to (4). (6) The guide mechanism is provided in at least two or more locations. At least two of the guide mechanisms are arranged apart from each other in the axial direction. (5) Test apparatus for ball screw devices as described above. (7) The moving part has a contact surface facing the first direction, The reaction force generating mechanism has opposing surfaces that face the second direction and contact the contact surface, One of the contact surface and the opposing surface is provided with a plurality of rolling elements to reduce friction between the contact surface and the opposing surface. A test apparatus for a ball screw device as described in any one of (1) to (6). (8) One of the aforementioned orthogonal directions is designated as the first orthogonal direction. The other of the aforementioned orthogonal directions shall be the second orthogonal direction. A support portion for a biasing part is arranged in the second orthogonal direction with respect to the moving part and is movable in the orthogonal direction, A biasing part is positioned between the moving part and the support part for the biasing part, and exerts a biasing force in the orthogonal direction, A moving device for moving the support portion for the biasing portion in the orthogonal direction, Equipped with, When the support portion for the biasing portion moves in the first orthogonal direction and the length of the biasing portion in the orthogonal direction becomes smaller than its natural length, the biasing portion exerts a biasing force that biases the moving component in the first orthogonal direction. A test apparatus for a ball screw device as described in any one of (1) to (7). (9) The aforementioned mobile device is Radial motor and A radial ball screw device that operates using the torque generated by the radial motor to move the biasing support in the orthogonal direction, It is equipped with (8) Test apparatus for ball screw devices as described above. [Explanation of Symbols]

[0099] 1, 1B support part 2 Actuator 3 Load device 10, 10A Reaction force generation mechanism 11 Connecting part 20 First motor 21, 24, 38, 69 Main body 23 Torque Sensor 30 Axial Motors 33 Load-side first ball screw device 37 First support part for biasing part 40, 71 flange 41, 53, 72 Linear guides 45 1st biasing section 47 Load Cells 48 Pressing part 49 Opposite side 50 movable parts 51 Housing 52 Through hole 56 Contact surface 60 Radial Load Mechanism 61 Radial motor 64 Load-side second ball screw device 68 Second support part for biasing part (support part for biasing part) 75 Second biasing section Testing apparatus for 100, 100A, and 100B ball screw devices. 101 Base 110 Ball screw device 111 Screw shaft 112 Nut

Claims

1. A support part that rotatably supports one of the rotating parts of a ball screw device, the screw shaft and the nut, and linearly supports the other linear part, A first motor that generates torque to rotate the aforementioned rotating part, A loading device that applies a load to the aforementioned linear motion component, Equipped with, The direction parallel to the central axis of the screw shaft is defined as the axial direction. One of the axial directions is designated as the first direction, The other direction in the axial direction is designated as the second direction. The direction perpendicular to the aforementioned axial direction is defined as the orthogonal direction. The aforementioned load device is A movable component is positioned in the first direction relative to the linear motion component and is movable in the axial direction and the orthogonal direction, A reaction force generating mechanism is positioned in the first direction relative to the moving part and presses the moving part from the first direction, A radial loading mechanism that moves the moving component in the orthogonal direction, Equipped with, The moving component is movable relative to the reaction force generating mechanism in the direction perpendicular to the said direction. The moving component has a connecting portion that can transmit loads in the second direction and the orthogonal direction to the linear component. Testing device for ball screw devices.

2. The connecting portion is formed from the same material as the movable part and is integrally formed with the movable part. A test apparatus for a ball screw device according to claim 1.

3. The connecting portion is a separate component from the movable part. A test apparatus for a ball screw device according to claim 1.

4. The connecting portion is designed to be fitted into the linear motion component. A test apparatus for a ball screw device according to claim 1.

5. The aforementioned load device is A housing having a through hole that penetrates in the axial direction, into which the movable component is inserted, and which supports the movable component so as to be movable in the axial direction, A guide mechanism that supports the housing so as to be movable in the orthogonal direction, Equipped with, The radial loading mechanism abuts against or connects to the housing from the orthogonal direction. A test apparatus for a ball screw device according to claim 1.

6. The guide mechanism is provided in at least two or more locations. At least two of the guide mechanisms are arranged apart from each other in the axial direction. Test apparatus for ball screw device according to claim 5.

7. The moving part has a contact surface facing the first direction, The reaction force generating mechanism has opposing surfaces that face the second direction and contact the contact surface, One of the contact surface and the opposing surface is provided with a plurality of rolling elements to reduce friction between the contact surface and the opposing surface. A test apparatus for a ball screw device according to claim 1.

8. One of the aforementioned orthogonal directions is designated as the first orthogonal direction. The other of the aforementioned orthogonal directions shall be the second orthogonal direction. A support portion for a biasing part is arranged in the second orthogonal direction with respect to the moving part and is movable in the orthogonal direction, A biasing part is positioned between the moving part and the support part for the biasing part, and exerts a biasing force in the orthogonal direction, A moving device for moving the support portion for the biasing portion in the orthogonal direction, Equipped with, When the support portion for the biasing portion moves in the first orthogonal direction and the length of the biasing portion in the orthogonal direction becomes smaller than its natural length, the biasing portion exerts a biasing force that biases the moving component in the first orthogonal direction. A test apparatus for a ball screw device according to any one of claims 1 to 7.

9. The aforementioned mobile device is Radial motor and A radial ball screw device that operates using the torque generated by the radial motor to move the biasing support in the orthogonal direction, It is equipped with Test apparatus for ball screw device according to claim 8.

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